Significance of serological markers in the disease course of ulcerative colitis in a prospective clinical cohort of patients
Significance of serological markers in the disease course of ulcerative colitis in a prospective clinical cohort of patients
Gyorgy Kovacs 0 1 2
Nora Sipeki 0 1 2
Boglarka Suga 0 1 2
Tamas Tornai 0 1 2
Kai Fechner 0 2
Gary L. Norman 0 2
Zakera Shums 0 2
Peter Antal-Szalmas 0 2
Maria Papp 0 1 2
0 Funding: Supported by Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences (BO/00426/11), Internal Research Grant (RH/885/ 2013) of University of Debrecen and Research Grant of University National, Research, Development and Innovation Office (K 115818, 2015/1), IOIBD Research Grant (2012-2015). These funders had no role in study design , data
1 Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary, 2 Institute of Experimental Immunology , Euroimmun AG, LuÈ beck, Germany, 3 Inova Diagnostics , Inc., San Diego, California, United Statesof America, 4 Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen , Debrecen , Hungary
2 Editor: Matti Waterman, Rambam Health Care Campus , ISRAEL
Background & aims To determine the prognostic potential of classic and novel serologic antibodies regarding unfavorable disease course in a prospective ulcerative colitis (UC) patient cohort, since few and conflicting data are available in the literature regarding this matter.
187 consecutive patients were studied prospectively (median follow-up: 135 months) from a
single referral IBD center in Hungary. Sera were tested for different IgA/IgG type
autoantibodies (anti-neutrophil cytoplasmic [ANCA], anti-DNA-bound-lactoferrin [anti-LFS],
antigoblet cell [anti-GAB] and anti-pancreatic [PAB: anti-CUZD1 and anti-GP2)]) by indirect
immunofluorescence technique and for anti-microbial (anti-Saccharomyces cerevisiae
[ASCA] IgG/IgA and anti-OMP Plus™ IgA) antibodies by enzyme-linked immunosorbent
A total of 73.6%, 62.4% and 11.2% of UC patients were positive for IgA/IgG type of atypical
perinuclear-ANCA, anti-LFS and anti-GAB, respectively. Occurrences of PABs were 9.6%,
while ASCA IgA/IgG and anti-OMP IgA were 17.6% and 19.8%, respectively. Antibody
status was stable over time. IgA type PABs were more prevalent in patients with primary
sclerosing cholangitis (37.5% vs. 4.7% for anti-CUZD1 and 12.5% vs. 0% for anti-GP2, p<0.001
for both). IgA type ASCA and anti-CUZD1 antibodies were associated with higher risk of
requirement for long-term immunosuppressant therapy in Kaplan-Meier analysis (pLogRank
<0.01 for both). However, in multivariate Cox-regression analysis only ASCA IgA (HR: 2.74,
95%CI: 1.46±5.14, p<0.01) remained independent predictor. UC-related hospitalization due
to disease activity was only associated with multiple antibody positivity (for 3 or more; HR
collection and analysis, decision to publish, or
preparation of the manuscript. They only provided
financial support in the form of authors' salaries
and/or research materials. Inova Diagnostics, Inc.,
as a funder provided support in the form of salaries
for authors [GLN, ZS] and partially research
material (QUANTA Lite® ELISA for the detection of
ASCA IgG /IgA and anti-OMP PlusTM antibodies),
but the commercial company itself did not have
any additional role in the study design, data
collection and analysis, decision to publish, or
preparation of the manuscript; only the co-authors
(GLN, ZS) did.
Competing interests: Regarding financial conflicts
of interest Gary L. Norman, Zakera Shums are
employed by Inova Diagnostics, Inc., San Diego,
California and are getting personal fees from the
company, while Kai Fechner works for the Institute
of Experimental Immunology, Euroimmun AG,
23560 Luebeck, Germany. For the remaining
authors none were declared. Inova Diagnostics,
Inc., as a funder provided support in the form of
salaries for authors [GLN, ZS] and partially
research material (QUANTA Lite® ELISA for the
detection of ASCA IgG/IgA and anti-OMP Plus TM
antibodies), but the commercial company itself did
not have any additional role in the study design,
data collection and analysis, decision to publish, or
preparation of the manuscript; only the co-authors
(GLN, ZS) did. This does not alter our adherence to
PLOS ONE policies on sharing data and materials.
Abbreviations: ANCA, anti-neutrophil cytoplasmic
antibodies; ASCA, anti-Saccharomyces cerevisiae
antibody; AZA, azathioprine; BT, bacterial
translocation; CD, Crohn's disease; CI, confidence
interval; CUZD1, CUB and zona pellucida-like
domains 1; ELISA, enzyme-linked immunosorbent
assay; GP-2, glycoprotein 2; HR, hazards ratio;
IBD, inflammatory bowel diseases; Ig,
immunoglobulin; IIFT, indirect
immunofluorescence test; IQR, inter quartile range;
LFS, lactoferrin; OR, odd ratio; PAB, pancreatic
antibody; P-ANCA, perinuclear anti-neutrophil
cytoplasmic antibodies; PSC, primary sclerosing
cholangitis; TNF, tumor necrosis factor; UC,
2.03 [95% CI: 1.16±3.56]; p = 0.013). None of the individual antibodies or their combination
was associated with the risk of development of extensive disease or colectomy.
Even with low prevalence rates, present study gives further evidence to the role of certain
antibodies as markers for distinct phenotype and disease outcome in UC. Considering the
result of the multivariate analysis the novel antibodies investigated do not seem to be
associated with poor clinical outcome in UC, only a classic antibody, IgA subtype ASCA
remained an independent predictor of long-term immunosuppressive therapy.
Enhanced antibody formation in the serum is a well-known feature of inflammatory bowel
diseases (IBD). A wide range of anti-microbial and autoantibodies have been reported to be
associated with either Crohn's disease (CD) or ulcerative colitis (UC) [
antibodies are formed against different surface carbohydrate (glycans [
]) or protein antigens of
various gut microbes [
], while autoantibodies are directed against host proteins. Currently,
the most relevant anti-microbial antibody is the ASCA (anti-Saccharomyces cerevisiae
antibody), while the major autoantibody is the ANCA (anti-neutrophil cytoplasmic antibody).
The panel of serologic antibodies, however, has continuously been expanding [
] calling for
clarification of whether these new markers are superior or add value to the conventional
markers. Existence of serologic markers might be considered as a reflection of the enhanced
microbial challenge to the gut [
] due to a disturbed gut innate immune system that triggers an
exaggerated adaptive immune response. These serologic antibodies may also be actively
involved in the pathophysiology of gut inflammation in IBD [
Serologic antibodies play a potential role in providing an insight into the etiopathogenesis
of IBD, establishing the diagnosis of IBD and to differentiating CD from UC. Currently, their
most fascinating and relevant potential is to stratify the risk of evolving a complicated disease
course that might dictate earlier more aggressive treatment [
]. This latter issue was extensively
studied in CD [
], however, data are few and conflicting regarding the association of serologic
markers to the disease course [9±14], medical treatment and response to therapy [
9, 10, 13
patients with UC, especially with the newly discovered antibodies. Thus a comprehensive
evaluation of a panel of serologic antibodies in a large prospectively followed UC cohort is
The aims of the present study were to investigate: (1) long-term stability of a panel of
serologic antibodies comprising classic and newly discovered markers, (2) associations between
the presence of antibodies and the clinical phenotype of the disease, (3) prognostic potential of
these antibodies with regards to the long-term disease course in a large prospective referral
adult UC cohort.
Materials and methods
We performed a cohort study among adult UC patients in a Hungarian tertiary IBD referral
center (Gastroenterology Department of Institute of Medicine, University of Debrecen). The
baseline clinical data regarding this cohort overlap with our previous studies [
2 / 18
hereby we present an extended follow up time with nearly 2 and a half years and re-evaluation
of the outcomes. We used the same step by step thorough statistical evaluations; therefore the
text appeared to reproduce information already reported in detail elsewhere.
Diagnosis of IBD was based on the Lennard±Jones criteria [
]. Detailed clinical
phenotypes were captured at inclusion. Clinical data were determined by thorough review of
patients' medical records, which had been collected in a uniform format described in detail in
our previous studies [
]. Medical records that documented age at presentation, disease
extent , presence of extraintestinal manifestations [EIM] and familial IBD, smoking habits,
medication use, UC-related hospitalization due to disease activity, development of extensive
disease (from E1/E2 to E3) and need for colectomy, were retrospectively analyzed for the
period prior to the prospective follow-up. At enrolment, clinical disease activity was calculated
according to the partial Mayo score [
]. Mayo score 3 was defined as a state of remission
and >4 as a state of active disease. Endoscopic activity was determined according to the
endoscopic component of the Mayo score [
]. A state of active disease was defined as 1 points
according to endoscopic partial Mayo score.
Phenotypical characterization of IBD patients during prospective
183 of 187 UC patients were available to be enrolled into a prospective follow-up study, where
the treating IBD physicians registered laboratory data, endoscopic and imaging findings,
disease activity, medical treatment, date of UC-related hospitalization, development of extensive
disease (from E1/E2 to E3) and colectomy during regular and extraordinary outpatient
followup visits and inpatient stays. Maximal disease extent (proctitis, left-sided colitis, and extensive
], observed during endoscopic follow-up was also registered. UC-related
hospitalization was defined as any admission for the treatment of UC disease activity. Colectomy
performed for medically refractory disease was considered in analyses. In Hungary, a follow-up
visit is usually scheduled for every 6 months at a specialized gastroenterology center (the actual
interval varies between 3±6 months). The treatment algorithms, both the medical and the
surgical, are harmonized and followed the ECCO guidelines. Need for colectomy and its timing is
a consistent multidisciplinary decision with the collaboration of the gastroenterologist,
radiologist, and surgeon [21±23]. Collected data were transferred and stored in a database for
analysis. In May 31, 2015, all patients' charts and database were reviewed and updated for the data
points mentioned above. Follow-up for a particular patient was terminated if there was no
further record available.
The treating physicians were aware of the antibody seropositivity of the patients, but did
not incorporate them into their regular clinical decision making (e.g. treatment choices),
except only in case of selected differential diagnostic problems (using ASCA and pANCA
status to distinguish CD, especially patients with only colonic localization [L2 according to
Montreal classification], from UC), alongside with ECCO guidelines on this matter [
1, 24, 25
Serologic antibody determination
Sera obtained at enrolment were separated from venous whole blood and stored at -80ÊC.
Atypical P-ANCA, anti-LFS, anti-goblet, anti-GP2 and anti-CUZD1 IgA and IgG were
detected using cell-based indirect immunofluorescence tests (IIFT) [Morbus-Crohn Mosaic 1,
Euroimmun Medizinische Labordiagnostika AG, LuÈbeck, Germany] in a manner previously
]. A specific fluorescence at a dilution of 1:32 or higher was considered positive
for P-ANCA and anti-LFS and 1:10 or higher for anti-goblet, anti-CUZD1 and anti- GP2
3 / 18
antibodies. The interpretation of ANCA pattern was based on the behavior of the specimens
on ethanol- and formalin- fixed slides according to previously reported [
Both serum IgG and IgA levels of anti-Saccharomyces cerevisiae antibodies (ASCA) and
anti-OMP Plus™antibodies were evaluated by enzyme-linked immunosorbent assay (ELISA)
separately [QUANTA Lite1, Inova Diagnostics, San Diego, CA]. The results are presented as
arbitrary units with a cut-off value for positivity of 25 Units.
Sera were documented both, in absolute values and in frequency of positivity. Additionally,
in case of each antibody, a highest quartile was defined by titers above laboratory cut-off values
belonging to the Q3-Q4 range (75th-100th percentiles). We used these in the quantitative
analysis of associations between antibody titers and poor disease outcomes.
To evaluate the stability of various serologic antibodies [status of positive or negative for a
respective antibody], we analyzed samples from the same patient over various arbitrary
timepoints during the disease course. At least two serum samples were taken from each of the
majority of UC patients [n = 106] and re-tested for all different serologic antibodies.
Variables were tested for normality using Shapiro Wilk's W test. Continuous variables were
summarized as means (standard deviation [SD]) or as medians (interquartile range [IQR])
according to their homogeneity. To evaluate differences within patient subgroups, the
following statistical methods were used. Categorical variables were compared with Fisher's exact test
or χ2 test with Yates correction, linear-by-linear association, as appropriate. Continuous
variables were compared with Student's t test, one-way analysis of variance [ANOVA], or
MannWhitney's U test or Kruskal-Wallis H test with post hoc analysis [Dunn's multiple comparison
test]. Kaplan-Meier survival curves were plotted for analyzing the association between
categorical clinical variables or serologic antibodies and unfavorable disease outcomes during
followup with LogRank testing or Cox-regression analysis in the time-dependent models.
Associations are given as odds ratio [OR] and hazard ratio [HR] with a 95% confidence intervals [CI].
A 2-sided probability value < 0.05 was considered to be statistically significant. A post-hoc
power analysis was performed in Stata (v13.0) with a detailed description of the evaluation and
results provided in the Supplementary Material (S1 File). For statistical analysis, GraphPad
Prism 6 [San Diego, CA] and SPSS 22.0 [SPSS, Chicago, IL], Stata (v13.0) [StataCorp. 2013.
Stata Statistical Software: Release 13. College Station, TX: StataCorp LP] programs were used.
The regional (the Institutional Review Board of the University of Debrecen) and national (the
Hungarian National Review Board) committee (DEOEC RKEB/IKEB 3515±2011, 3880/2012/
EKU [59/PI/2012]) for research ethics approved the study protocol. Each patient was informed
of the nature of the study and signed an informed consent form.
Clinical characteristics of UC patients
In all, 187 well-characterized, unrelated, consecutive UC patients with a complete clinical
follow-up (age range at presentation: 8±68 years, at first sampling: 17±85 years) seen at our
Outpatient Clinic were enrolled between January 1, 2005 and June 1, 2010. The clinical
characteristics of the patients at time of inclusion and sample procurement are presented in Table 1.
Median follow-up from the diagnosis months 135 [IQR]: 84±213.
4 / 18
: median (IQR)
☐: 183 UC patients had follow-up from the diagnosis
⃠180 data were available
Disease extent: E1: proctitis, E2: left-sided colitis, E3: extensive colitis
Frequency of serologic antibodies
A total of 73.6%, 62.4% and 11.2% of UC patients were positive for IgA/IgG type of atypical
P-ANCA, anti-LFS and anti-GAB, respectively. Both types of PAB occurred as well, 9% of the
patients were positive for anti-CUZD1 ( anti-rPAg1) and 0.6% for anti-GP2 ( anti-rPAg2)
IgA/IgG. ASCA IgA/IgG and anti-OMP IgA positivity was 17.6% and 19.8%, respectively.
Frequencies of the different antibodies in UC patients are summarized in Table 2.
5 / 18
Stability of serologic antibodies
Median time between sample procurements was 21.1 months [IQR, 11.2±41.1]. Interestingly,
the status of most serologic antibodies was very stable over time regarding both IgA and IgG
subtypes, with only 10% of cases changing their antibody status over time. Atypical
PANCA and anti-LFS antibodies, showed somewhat higher variation up to 23% of cases.
Stability data of various serologic antibodies are summarized in Table 3. In case of anti-OMP IgA
data regarding stability was available in only 23 UC patients, 82.6% of them were stable
negative, while 17.4% appeared to be stable positive. None of them changed their antibody status
In addition, no association was detected between the status of various serologic antibodies
and the clinical or endoscopic disease activity [actual partial or endoscopic part of Mayo] at
the time of sample procurement (data available in the public repository ªFigshareº with the
following related doi number: 10.6084/m9.figshare.4765102).
Associations of serologic antibody profiles to clinical phenotype of the
No significant association was demonstrated between presence of serologic antibodies and
gender, younger age at diagnosis (age 16 years), or colitis extent.
Presence of certain antibodies was less prevalent in patients with EIM: anti-LFS antibodies
in ocular diseases (20.0% vs. 64.9%, p = 0.004 for IgG subtype), while atypical P-ANCA (45.8%
vs. 74.0%, p = 0.005for IgG subtype) and anti-LFS antibodies (0.0% vs. 17.5%, p = 0.026 for IgA
6 / 18
ASCA: anti-Saccharomyces cerevisiae antibody, LFS: lactoferrin, CUZD1: CUB and zona pellucida-like domains 1,GP2: glycoprotein 2, P-ANCA: perinuclear
antineutrophil cytoplasmic antibodies
subtype) in arthritis. While other antibodies were more prevalent in patients with EIM: such as
GAB in ocular diseases (40.0% vs. 9.5%, p = 0.016for IgG/IgA subtype). None of the antibodies
was, however, associated with cutaneous manifestation of the disease.
IgA but not IgG types PABs were more prevalent in patients with PSC (37.5% vs. 4.7% for
anti-CUZD1 and 12.5% vs. 0% for anti-GP2, p<0.001 for both).
Lastly, presence of anti-LFS antibodies was negatively associated with current smoking
status (No vs. Yes, 65.6% vs. 33.3%, p = 0.01 for IgA/IgG subtype) as well.
All of these data are presented in Table 4.
Significance of serologic antibodies in the risk of unfavorable disease
In Kaplan-Meier analysis, the presence of certain antibodies was associated with an increased
cumulative probability of study-endpoint events compared to the absence of these antibodies
(summarized in Table 5 and S1 Table).
Further analyzing the quantitative associations with unfavorable disease outcomes, we did
not find the use of highest quartiles as cut-off values superior compared to the original ones.
Cumulative probability of UC-related hospitalization was significantly higher in
antiCUZD1 IgG (78.6% vs. 28.8%, pLogRank = 0.031), but not in IgA positive cases at 135 months of
the follow-up period. In case of the latter antibody, evaluating at higher titer as a cut-off point
( 1:1000; HRCUZD1IgA: 1.91 [95% CI: 0.69±5.30]; p = 0.214), similar result was found to that
one obtained at lower cut-off value ( 1:10; HRCUZD1IgA: 2.16 [95% CI: 0.91±5.10]; p = 0.077).
At the same time, cumulative probability of need for long-term immunosuppressant
therapy with azathioprine [AZA] was significantly higher either in anti-CUZD1 IgG (78.1% vs.
36.2%, pLogRank = 0.008) or IgA positive cases (84.1% vs. 36.8%, pLogRank = 0.005) as compared
to antibody negative ones. The risk of need for long-term immunosuppressant therapy did not
differ according to the extent of anti-CUZD1 IgA antibody positivity (HRCUZD1IgA: 2.53 [95%
CI: 1.09±5.91]; p = 0.032 for titer of 1:1000 and HRCUZD1IgA: 2.78 [95% CI: 1.31±5.89];
p = 0.007 for titer of 1:10). The presence of IgA as well as IgG type CUZD1 was associated
with the need of colectomy, however with only borderline significance without clinically
7 / 18
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relevant cumulative probability differences (0.0 vs. 5.5%; pLogRank = 0.026 and pLogRank = 0.027,
respectively). Comparing higher serum antibody titers ( 1:1000; HRCUZD1IgA: 5.58 [95% CI:
1.15±27.04]; p = 0.033) with lower ones ( 1:10; HRCUZD1IgA: 5.01 [95% CI: 1.03±24.28];
p = 0.045) carried the same risk.
Cumulative probability of UC-related hospitalization did not differ according to IgA or
IgG ASCA status. The use of higher cut-off value of IgA type ASCA ( 47 U; HRASCAIgA: 2.34
[95% CI: 0.85±6.50]; p = 0.102) in the analysis yielded similar results to lower titer ( 25 U;
9 / 18
HRASCAIgA: 1.65 [95% CI: 0.81±3.36]; p = 0.165). On the contrary, presence of IgA, but not the
IgG type ASCA was associated with an increased cumulative probability of the need for
longterm immunosuppressant therapy with AZA (64.2% vs. 34.7%, pLogRank = 0.003) (Fig 1). In
case of high ASCA IgA antibody titer ( 47 U; HRASCAIgA: 3.55 [95% CI: 1.53±8.25]; p = 0.003)
the risk of need for long-term immunosuppressant therapy was similar to those observed at
lower positive titer ( 25 U; HRASCAIgA: 2.43 [95% CI: 1.33±4.46]; p = 0.004). However only
the presence of IgG type ASCA was moderately associated with need of colectomy (13.6% vs.
3.8%, pLogRank = 0.014).
As for IgA or IgG type atypical P-ANCA, anti-LFS, GAB or IgA type anti-OMP antibodies,
no differences between antibody positive and negative patients were observed in terms of
either the study-endpoint events (Table 5).
Covariates. Analysis of clinical factors associated with UC-related hospitalization and
requirement for long-term immunosuppressant therapy with azathioprine using
KaplanMeier and univariate Cox-regression analysis is shown in Table 5. Colitis extent (Fig 1) and
male gender but neither age of onset nor smoking habits were significantly associated with
these study endpoints.
None of the clinical factors were significantly associated with need for colectomy (S1
Lastly, development of extensive disease was also considered as an unfavorable outcome. In
patient presenting with disease location E1 or E2 (n = 134) none of the examined serologic
antibodies were associated with a change to a more extended disease (E3 according to
Montreal classification) (S2 Table).
Multivariate analysis. Cox-regression analysis and the backward elimination procedure,
taking serologic antibodies and all clinical covariates into account, indicated that out of the
serologic markers, the presence of IgA type ASCA was independently associated with the
higher risk of need for long-term immunosuppressant therapy with AZA (HR: 2.51, 95%CI:
1.33±4.74, p = 0.005). None of the serologic antibodies were independently associated with the
higher risk of the UC-related hospitalization (Table 5).
From the clinical parameters, extensive colitis was associated with a higher risk of
UCrelated hospitalization (HR: 11.67, 95%CI: 1.59±85.56, p = 0.016), and the need for long-term
immunosuppressant therapy with AZA (HR: 3.15, 95%CI: 1.95±5.10, p<0.001) (Table 5).
Evaluation of multiple positivity for different antibodies was performed; co-existence of
three or more different types of antibodies was associated with UC-related hospitalization
along with long-term immunosuppressant therapy but not associated with development of
extensive disease or need for colectomy in univariate and multivariate time dependent analysis
as well. These result appeared to be superior to single antibody positivity in these unfavorable
disease outcomes (Table 5).
In the present study, we investigated the clinical importance of an extensive panel of serologic
antibodies comprising both classic and newly discovered auto- and anti-microbial antibodies
in the prediction of the long-term disease course in adult UC patients. To our knowledge, this
is the largest prospective referral cohort to date, which has been examined by such a wide
range of serologic antibodies.
In our cohort, the seropositivity rate of classic serologic antibodies, namely atypical
P-ANCA and ASCA, and also anti-OMP antibody corresponds to those previously reported in
UC (45±82%, 5±15%, and 20±24%, respectively) [
]. It should be noted, however, that IgA
type anti-OMP antibody examined in the present study is clearly different from anti-OmpC.
10 / 18
Fig 1. Kaplan±Meier survival plot of need for long-term immunosuppressant therapy with azathioprine in
ulcerative colitis during follow-up.
11 / 18
Similar prevalence rate of anti-OmpC (5±28%) [
] and resemblance in nomenclature
sometimes causes confusion in the literature. Anti-OMP antibody is directed against multiple
bacterial proteins derived from two species of intestinal bacteria (one gram positive and one gram
negative). Neither bacteria are from the phylum proteobacteria, of which Escherichia coli is a
member. At the same time, anti-OmpC antibody is specifically directed to the outer membrane
protein C transport protein of Escherichia coli. Fewer data are available regarding the
prevalence of target specific PABs (anti-GP2 and anti-CUZD1) in patients with UC. In the largest
study assessing UC patients (n = 136), both the anti-GP2 and the anti-CUZD1 seropositivity
rates were low, 2.9% and 5.9%, respectively, similar to our findings [
Prognostic value of serologic antibodies relies on documentation of their stability over
time. Accordingly, in the present study we extensively assessed the long-term stability of
various antibodies. We found the status of serologic antibodies was not associated with actual
disease activity, and positivity rates were stable over time. Most studies in UC that have measured
antibodies during active and inactive disease have shown no correlation between P-ANCA
and disease severity [
]. Regarding antibody stability, in a previous study of Vecchi et al.[
atypical p-ANCA IgG status remained constant over time (50.8 month time period) when
evaluated at more than one time point in a small cohort of UC patients (n = 40). Change in
antibody status occurred in 25% of patients, similar to our findings. In our cohort changes of IgG
subtype of atypical p-ANCA was 14.4%, while IgA subtype was 23.2%. ASCA and other
serologic antibodies showed even lower variation ( 10% of cases). This is consistent with previous
data provided by Rieder et al. [
]. Anti-glycan antibody (such as ASCA) status remained
unchanged from the status determined at the initial sample procurement in the vast majority
of UC and CD patients. The median time between sample procurements, however, was
relatively short (6.2 months).
Reports regarding association of serologic markers with long-term disease course in UC
have generally been restricted to the evaluation of atypical P-ANCA and ASCA. Newly
identified antibodies have not been well studied in this clinical setting. Possible differences according
to antibody subtypes (IgA or IgG type) have also not been within the scope of these studies.
Our previous findings that IgA, but not IgG types of PAbs, were associated with complicated
disease course in patients with CD support this latter approach [
]. In the present study we
aimed to fill these gaps.
In previous longitudinal clinical studies, association between serologic antibodies and
adverse disease outcome yielded somewhat discordant results, for various reasons. From the
clinical point of view, unfavorable disease outcomeÐbeyond colectomyÐwas not defined in
a unified manner in these studies. In addition, study populations were different as well as
regarding the sample size, study design (referral or population-based patient cohort) or
follow-up time. It is known that the proportion of IBD patients developing an unfavorable disease
outcome could be significantly different in referral and population-based cohorts [
Likewise reported prevalences of serologic antibodies are lower in population-based cohorts [
In the present study, four primary end-points were selected to define unfavorable disease
outcome in UC: development of extensive disease, need for colectomy, requirement for one or
more UC-related hospitalization due to disease activity and need for long-term
immunosuppressant therapy with AZA.
A change to a more extended disease (E3 according to Montreal classification) can be
considered as an unfavorable disease outcome worth to evaluate, however only limited data is
available in the literature regarding proximal disease progression over time, as well as the
related factors, especially serologic markers having an impact on this outcome. The majority of
studies were conducted on this matter more than 20 years ago [30±34].Rate of disease extent
progression reported previously varies from 15% to 53% depending on disease duration at the
12 / 18
end of follow-up time (5, 10 and 25 years) [30±43]. Until now, the most thorough over time
extent evaluation was presented in a Swiss IBD Cohort Study (n = 918), where 9.48% of UC
patients (E1 or E2) developed E3 disease during follow up (median time: 9 years) [
found similar progression rate to an extensive disease (n = 134) in our UC patients (12.7%)
with similar median follow up time (8.6 years). The strength of our study is that we analyzed
for the first time, whether the presence or absence of the classic and novel antibodies are
associated with a shorter time to development of an extensive disease, however we failed to prove
any significant association. Although, the lack of prognostic potential of these antibodies in
this particular outcome should be interpreted cautiously due to low event and patient numbers
in antibody positive groups. Former small-scale referral cohort studies demonstrated [
] that the presence of P-ANCA was associated with the need for colectomy in UC. However,
more recent large-scale studies, either in the population-based [
] or referral [
9, 10, 46
cohorts, have not been able to confirm these early reports. Two population-based studies
(Norwegian IBSEN study , n = 357 and EC-IBD multicenter study[
], n = 432) did not
demonstrate increased risk of colectomy in the presence of P-ANCA or ASCA seropositivity [
Two additional referral cohort studies from Canada [
] further confirmed the lack of
association between serologic antibodies and need for colectomy. Beyond P-ANCA and ASCA
seropositivity, other serologic antibodies, such as anti-OmpC or CBir1 , were also not
associated with the risk of colectomy. Only one single study [
] found that anti-OmpC positivity
was associated to the requirement for colectomy. In the present referral cohort study, we also
did not find clinically relevant associations between the requirement for colectomy and the
presence of either the classic or the newly identified serologic antibodies, including anti-OMP.
The anti-OMP assay used in current study is significantly different from anti-OmpC assay, as
Concerning UC-related hospitalization as an unfavorable diseases outcome, no significant
association was found with P-ANCA and ASCA seropositivity in a recent large-scale referral
cohort study of Kevans et al.[
](n = 230). Colitis extent was the single variable of the clinical
factors that associated with the study endpoint (HR 2.7, 95%CI: 1.5±4.6, p = 0.006). In
agreement with that study, only the disease extent, and not any of the serologic antibodies, was able
to predict UC-related hospitalization (HR 11.7, 95%CI: 1.6±85.6, p = 0.016) in our cohort.
Requirement for, or response to, certain medical therapies as an adverse outcome in UC
was also evaluated in former studies. Mainly corticosteroid or biological therapy was assessed
either individually [
] or in combination as components of prognostic profile groups
describing disease severity [
]. The need for more intense treatment with AZA was assessed in a
single study of Soleberg et al.[
]). P-ANCA positive patients had about 4-fold higher risk of
receiving AZA treatment during follow up (OR: 4.14, 95%CI: 1.73±9.82, p = 0.005). However,
in our study, ASCA, and not the P-ANCA seropositivity was associated with a more active
course of UC, as there was a significant relationship between presence of ASCA and the overall
use of AZA. Interestingly, only IgA, but not IgG type of antibody showed this link. Gut
mucosal immune system plays a central role in the IgA antibody formation, and this may at least
partly reflect an immune response against an overwhelming microbial challenge. In addition,
IgA type autoantibodies are considered as a sign of immunological response to enteric antigens
in other diseases associated with enhanced bacterial translocation. Our group reported that
IgA type antibodies have a pivotal role in the development of disease-specific complications
compared with the IgG antibody subtype [
]. Remarkably, in the present cohort the
occurrence of IgA type target specific PAbs but not IgG type was significantly higher in those
patients with concomitant PSC. The same association was reported previously [
] in a cohort
of our CD patients. That was confirmed later by Michaels et al. [
] in UC and CD as well.
13 / 18
These findings might serve as an additional hint towards the importance of gut mucosal
immune system dysfunction in the development of hepatobiliary manifestations [
Based on the experience gained from previous serological studies in IBD [
those performed by us as well, we know that an increasing number or magnitude of
seropositivity can yield higher association with disease complications than single markers. In the
present study, however we were not able to confirm that the use of highest quartiles as cut-off
values were superior compared to the original ones. Although, we have to highlight that the
lack of associations regarding highest antibody titers can be the result of a very limited number
of patients belonging to these categories. Distinctly, multiple seropositivity, namely the
coexistence of three or more different types of antibodies, results proved to be superior compared
to single antibody positivity regarding certain outcomes, such as UC-related hospitalization
and need for long-term immunosuppressant therapy.
This study has some limitations: (1) our hospital is a regional referral center for IBD
patients introducing a selection bias; (2) relatively small number of subjects underwent
colectomy but it is in accordance with previous reports from Eastern Europe [
]; thus any lack of
significant association could also be explained by insufficient statistical power (type 2 error);
(3) the wide range of seropositivity of the examined antibody panel (9±73%) did not make
possible an equally powered evaluation in case of each certain markers and warrants further
validation in larger patient cohort. (4) our patient cohort is followed prospectively and the
database is updated regularly for that concern. Serum sampling, however, occurred later in
subject's disease course rather than at or soon after diagnosis. Median disease duration was 4
years at serum drawing which is a significantly shorter interval than in previous studies. At the
same time, sufficient prospective follow-up (median, 11 years) was available after sampling.
Seventy-six percent of our patients had at least 5 years of follow-up which is the period
suggested by Silverberg et al.[
] that is required for evaluation of long-term outcomes. Based on
these and the stability data of the present study, we believe that our serologic findings provide
reliable prognostic information for the whole disease course of UC, including near the time of
the diagnosis as well.
In conclusion, consistent with the majority of previous reports, we have shown that
presence of atypical P-ANCA is not associated with unfavorable disease outcome in UC. We did
not demonstrate any association of newly identified serologic antibodies with the unfavorable
disease outcome. We demonstrated, however, a novel association between the presence of IgA,
but not the IgG type ASCA and requirement for long-term immunosuppressant therapy with
AZA. Assessment of serologic antibody subtypes may prove to be an important novel
parameter. Further studies are now needed to validate and extend these results.
S1 Table. Univariate and multivariate Cox-regression analysis evaluating association
between clinical and serologic variables and the omitted study end-point colectomy.
S2 Table. Summary of Kaplan-Meier survival analysis forthe probability of the
development of extensive disease (E3) in UC patients.
S1 File. Post-hoc power analysis of antibody seropositivity and poor disease outcome
(UCrelated hospitalization and need for long-term immunosuppressant therapy).
14 / 18
Conceptualization: Gyorgy Kovacs, Nora Sipeki, Peter Antal-Szalmas, Maria Papp.
Formal analysis: Nora Sipeki, Tamas Tornai, Maria Papp.
Funding acquisition: Kai Fechner, Gary L. Norman, Zakera Shums, Maria Papp.
Investigation: Gyorgy Kovacs, Nora Sipeki, Boglarka Suga, Tamas Tornai, Gary L. Norman,
Zakera Shums, Peter Antal-Szalmas, Maria Papp.
Methodology: Nora Sipeki, Tamas Tornai, Kai Fechner, Gary L. Norman, Zakera Shums,
Peter Antal-Szalmas, Maria Papp.
Project administration: Gyorgy Kovacs, Peter Antal-Szalmas, Maria Papp.
Resources: Nora Sipeki, Tamas Tornai, Kai Fechner, Gary L. Norman, Zakera Shums, Peter
Antal-Szalmas, Maria Papp.
Supervision: Maria Papp.
Validation: Peter Antal-Szalmas, Maria Papp.
Visualization: Nora Sipeki, Boglarka Suga, Tamas Tornai, Maria Papp.
Writing ± original draft: Gyorgy Kovacs, Nora Sipeki, Maria Papp.
Writing ± review & editing: Boglarka Suga, Tamas Tornai, Kai Fechner, Gary L. Norman,
Zakera Shums, Peter Antal-Szalmas.
15 / 18
16 / 18
Pouch Disorders. Journal of Crohn's and Colitis. 2017; 11(6):649±70. https://doi.org/10.1093/ecco-jcc/
jjx008 PMID: 28158501
17 / 18
1. Papp M , Lakatos PL . Serological studies in inflammatory bowel disease: how important are they? Current opinion in gastroenterology . 2014 ; 30 ( 4 ): 359 ± 64 . Epub 2014/05/09. https://doi.org/10.1097/MOG. 0000000000000076 PMID: 24811052 .
2. Lakatos PL , Papp M , Rieder F. Serologic antiglycan antibodies in inflammatory bowel disease . The American journal of gastroenterology . 2011 ; 106 ( 3 ): 406 ± 12 . Epub 2011/01/20. https://doi.org/10.1038/ ajg. 2010 .505 PMID: 21245832 .
3. Rieder F , Kugathasan S. Circulating antibodies against bacterial wall products: are there arguments for early immunosuppression? Digestive diseases (Basel, Switzerland). 2012 ; 30 Suppl 3 : 55 ± 66 . Epub 2013/01/18. https://doi.org/10.1159/000342603 PMID: 23295693 .
4. Terjung B , Sohne J , Lechtenberg B , Gottwein J , Muennich M , Herzog V , et al. p -ANCAs in autoimmune liver disorders recognise human beta-tubulin isotype 5 and cross-react with microbial protein FtsZ . Gut . 2010 ; 59 ( 6 ): 808 ± 16 . Epub 2009/12/03. https://doi.org/10.1136/gut. 2008 .157818 PMID: 19951907 .
5. Papp M , Sipeki N , Vitalis Z , Tornai T , Altorjay I , Tornai I , et al. High prevalence of IgA class anti-neutrophil cytoplasmic antibodies (ANCA) is associated with increased risk of bacterial infection in patients with cirrhosis . Journal of hepatology . 2013 ; 59 ( 3 ): 457 ± 66 . Epub 2013/05/04. https://doi.org/10.1016/j. jhep. 2013 . 04 .018 PMID: 23639483 .
6. Pavlidis P , Romanidou O , Roggenbuck D , Mytilinaiou MG , Al-Sulttan F , Liaskos C , et al. Ileal inflammation may trigger the development of GP2-specific pancreatic autoantibodies in patients with Crohn's disease . Clinical & developmental immunology . 2012 ; 2012 : 640835 . Epub 2012/11/03. https://doi.org/10. 1155/ 2012 /640835 PMID: 23118780 .
7. Roggenbuck D , Reinhold D , Werner L , Schierack P , Bogdanos DP , Conrad K. Glycoprotein 2 antibodies in Crohn's disease . Advances in clinical chemistry . 2013 ; 60 : 187 ± 208 . Epub 2013/06/04. PMID: 23724745 .
8. Prideaux L , De Cruz P , Ng SC , Kamm MA . Serological antibodies in inflammatory bowel disease: a systematic review . Inflamm Bowel Dis . 2012 ; 18 ( 7 ): 1340 ± 55 . Epub 2011/11/10. https://doi.org/10.1002/ ibd.21903 PMID: 22069240 .
9. Kevans D , Waterman M , Milgrom R , Xu W , Van Assche G , Silverberg M. Serological markers associated with disease behavior and response to anti-tumor necrosis factor therapy in ulcerative colitis . Journal of gastroenterology and hepatology . 2015 ; 30 ( 1 ): 64 ± 70 . Epub 2014/07/22. https://doi.org/10.1111/ jgh.12661 PMID: 25041458 .
10. Waterman M , Knight J , Dinani A , Xu W , Stempak JM , Croitoru K , et al. Predictors of Outcome in Ulcerative Colitis. Inflamm Bowel Dis . 2015 ; 21 ( 9 ): 2097 ± 105 . Epub 2015/07/16. https://doi.org/10.1097/MIB. 0000000000000466 PMID: 26177304 .
11. Hoie O , Aamodt G , Vermeire S , Bernklev T , Odes S , Wolters FL , et al. Serological markers are associated with disease course in ulcerative colitis. A study in an unselected population-based cohort followed for 10 years . Journal of Crohn's & colitis . 2008 ; 2 ( 2 ): 114 ± 22 . Epub 2008/06/01. https://doi.org/10.1016/ j.crohns. 2007 . 10 .001 PMID: 21172201 .
12. Vecchi M , Bianchi MB , Calabresi C , Meucci G , Tatarella M , de Franchis R. Long-term observation of the perinuclear anti-neutrophil cytoplasmic antibody status in ulcerative colitis patients . Scand J Gastroenterol . 1998 ; 33 ( 2 ): 170 ± 3 . Epub 1998/03/28. PMID: 9517528 .
13. Solberg IC , Lygren I , Cvancarova M , Jahnsen J , Stray N , Sauar J , et al. Predictive value of serologic markers in a population-based Norwegian cohort with inflammatory bowel disease . Inflamm Bowel Dis . 2009 ; 15 ( 3 ): 406 ± 14 . Epub 2008/11/15. https://doi.org/10.1002/ibd.20781 PMID: 19009607 .
14. Elkadri AA , Stempak JM , Walters TD , Lal S , Griffiths AM , Steinhart AH , et al. Serum antibodies associated with complex inflammatory bowel disease . Inflamm Bowel Dis . 2013 ; 19 ( 7 ): 1499 ± 505 . Epub 2013/ 05/25. https://doi.org/10.1097/MIB.0b013e318281f2a1 PMID: 23702714 .
15. Papp M , Sipeki N , Tornai T , Altorjay I , Norman GL , Shums Z , et al. Rediscovery of the Anti-Pancreatic Antibodies and Evaluation of their Prognostic Value in a Prospective Clinical Cohort of Crohn's Patients: The Importance of Specific Target Antigens [GP2 and CUZD1] . Journal of Crohn's & colitis . 2015 ; 9 ( 8 ): 659 ± 68 . Epub 2015/05/15. https://doi.org/10.1093/ecco-jcc/jjv087 PMID: 25968583 .
16. Sipeki N , Davida L , Palyu E , Altorjay I , Harsfalvi J , Szalmas PA , et al. Prevalence, significance and predictive value of antiphospholipid antibodies in Crohn's disease . World journal of gastroenterology: WJG . 2015 ; 21 ( 22 ): 6952 ± 64 . Epub 2015/06/17. https://doi.org/10.3748/wjg.v21. i22 .6952 PMID: 26078573 .
17. Lennard-Jones JE . Classification of inflammatory bowel disease . Scand J Gastroenterol Suppl . 1989 ; 170 : 2±6; discussion 16±9 . Epub 1989/01/01. PMID: 2617184 .
18. Silverberg MS , Satsangi J , Ahmad T , Arnott ID , Bernstein CN , Brant SR , et al. Toward an integrated clinical, molecular and serological classification of inflammatory bowel disease: report of a Working Party of the 2005 Montreal World Congress of Gastroenterology . Canadian journal of gastroenterology = Journal canadien de gastroenterologie . 2005; 19 Suppl A:5a±36a. Epub 2005 /09/10. PMID: 16151544 .
19. Lewis JD , Chuai S , Nessel L , Lichtenstein GR , Aberra FN , Ellenberg JH . Use of the noninvasive components of the Mayo score to assess clinical response in ulcerative colitis . Inflamm Bowel Dis . 2008 ; 14 ( 12 ): 1660 ± 6 . Epub 2008/07/16. https://doi.org/10.1002/ibd.20520 PMID: 18623174 .
20. Schroeder KW , Tremaine WJ , Ilstrup DM . Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study . The New England journal of medicine . 1987 ; 317 ( 26 ): 1625 ± 9 . Epub 1987/12/24. https://doi.org/10.1056/NEJM198712243172603 PMID: 3317057 .
21. Dignass A , Eliakim R , Magro F , Maaser C , Chowers Y , Geboes K , et al. Second European evidencebased consensus on the diagnosis and management of ulcerative colitis part 1: definitions and diagnosis . Journal of Crohn's & colitis . 2012 ; 6 ( 10 ): 965 ± 90 . Epub 2012/10/09. https://doi.org/10.1016/j.crohns. 2012 . 09 .003 PMID: 23040452 .
22. Dignass A , Lindsay JO , Sturm A , Windsor A , Colombel JF , Allez M , et al. Second European evidencebased consensus on the diagnosis and management of ulcerative colitis part 2: current management . Journal of Crohn's & colitis . 2012 ; 6 ( 10 ): 991 ± 1030 . Epub 2012/10/09. https://doi.org/10.1016/j.crohns. 2012 . 09 .002 PMID: 23040451 .
23. Van Assche G , Dignass A , Bokemeyer B , Danese S , Gionchetti P , Moser G , et al. Second European evidence-based consensus on the diagnosis and management of ulcerative colitis part 3: special situations . Journal of Crohn's & colitis . 2013 ; 7 ( 1 ):1± 33 . Epub 2012/10/09. https://doi.org/10.1016/j.crohns. 2012 . 09 .005 PMID: 23040453 .
24. Harbord M , Eliakim R , Bettenworth D , Karmiris K , Katsanos K , Kopylov U , et al. Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 2 : Current Management . Journal of Crohn's and Colitis . 2017 ; 11 ( 7 ): 769 ± 84 . https://doi.org/10.1093/ecco-jcc/jjx009 PMID: 28513805
25. Magro F , Gionchetti P , Eliakim R , Ardizzone S , Armuzzi A , Barreiro-de Acosta M , et al. Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 1 : Definitions, Diagnosis, Extra-intestinal Manifestations , Pregnancy, Cancer Surveillance, Surgery, and Ileo-anal
26. Papp M , Altorjay I , Lakos G , Tumpek J , Sipka S , Dinya T , et al. Evaluation of the combined application of ethanol-fixed and formaldehyde-fixed neutrophil substrates for identifying atypical perinuclear antineutrophil cytoplasmic antibodies in inflammatory bowel disease . Clinical and vaccine immunology: CVI . 2009 ; 16 ( 4 ): 464 ± 70 . Epub 2009/02/06. https://doi.org/10.1128/CVI.00002-09 PMID: 19193830 .
27. Michaels MA , Jendrek ST , Korf T , Nitzsche T , Teegen B , Komorowski L , et al. Pancreatic Autoantibodies Against CUZD1 and GP2 Are Associated with Distinct Clinical Phenotypes of Crohn's Disease . Inflamm Bowel Dis . 2015 ; 21 ( 12 ): 2864 ± 72 . Epub 2015/08/15. https://doi.org/10.1097/MIB. 0000000000000564 PMID: 26273818 .
28. Rieder F , Schleder S , Wolf A , Dirmeier A , Strauch U , Obermeier F , et al. Serum anti-glycan antibodies predict complicated Crohn's disease behavior: a cohort study . Inflamm Bowel Dis . 2010 ; 16 ( 8 ): 1367 ± 75 . Epub 2009/12/22. https://doi.org/10.1002/ibd.21179 PMID: 20024902 .
29. Lakatos PL , Sipeki N , Kovacs G , Palyu E , Norman GL , Shums Z , et al. Risk Matrix for Prediction of Disease Progression in a Referral Cohort of Patients with Crohn's Disease . Journal of Crohn's & colitis . 2015 ; 9 ( 10 ): 891 ± 8 . Epub 2015/07/19. https://doi.org/10.1093/ecco-jcc/jjv127 PMID: 26188353 .
30. Niv Y , Bat L , Ron E , Theodor E. Change in the extent of colonic involvement in ulcerative colitis: a colonoscopic study . The American journal of gastroenterology . 1987 ; 82 ( 10 ): 1046 ± 51 . Epub 1987/10/01. PMID: 3661514 .
31. BrostroÈm O. Prognosis in Ulcerative Colitis. Medical Clinics of North America . 1990 ; 74 ( 1 ): 201 ± 18 . https://doi.org/10.1016/s0025- 7125 ( 16 ) 30596 - x PMID : 2404177
32. Riegler G , Manzione R , Esposito P , Carratu R. Change in the extent of idiopathic ulcerative proctocolitis . The Italian journal of gastroenterology . 1996 ; 28 ( 4 ): 211 ± 5 . Epub 1996/05/01. PMID: 8842836 .
33. Bresci G , Parisi G , Gambardella L , Banti S , Bertoni M , Rindi G , et al. Evaluation of clinical patterns in ulcerative colitis: a long-term follow-up . International journal of clinical pharmacology research . 1997 ; 17 ( 1 ): 17 ± 22 . Epub 1997/01/01. PMID: 9403349 .
34. Moum B , Ekbom A , Vatn MH , Elgjo K. Change in the extent of colonoscopic and histological involvement in ulcerative colitis over time . The American journal of gastroenterology . 1999 ; 94 ( 6 ): 1564 ± 9 . Epub 1999/06/11. https://doi.org/10.1111/j.1572- 0241 . 1999 . 01145 . x PMID : 10364026 .
35. Ayres RC , Gillen CD , Walmsley RS , Allan RN . Progression of ulcerative proctosigmoiditis: incidence and factors influencing progression . European journal of gastroenterology & hepatology . 1996 ; 8 ( 6 ): 555 ± 8 . Epub 1996/06/01. PMID: 8823569 .
36. Langholz E , Munkholm P , Davidsen M , Nielsen OH , Binder V . Changes in extent of ulcerative colitis: a study on the course and prognostic factors . Scand J Gastroenterol . 1996 ; 31 ( 3 ): 260 ± 6 . Epub 1996/03/ 01. PMID: 8833356 .
37. Etchevers MJ , Aceituno M , Garcia-Bosch O , Ordas I , Sans M , Ricart E , et al. Risk factors and characteristics of extent progression in ulcerative colitis . Inflamm Bowel Dis . 2009 ; 15 ( 9 ): 1320 ± 5 . Epub 2009/ 02/25. https://doi.org/10.1002/ibd.20897 PMID: 19235909 .
38. Gower-Rousseau C , Dauchet L , Vernier-Massouille G , Tilloy E , Brazier F , Merle V , et al. The natural history of pediatric ulcerative colitis: a population-based cohort study . The American journal of gastroenterology . 2009 ; 104 ( 8 ): 2080 ± 8 . Epub 2009/05/14. https://doi.org/10.1038/ajg. 2009 .177 PMID: 19436273 .
39. Solberg IC , Lygren I , Jahnsen J , Aadland E , Hoie O , Cvancarova M , et al. Clinical course during the first 10 years of ulcerative colitis: results from a population-based inception cohort (IBSEN Study) . Scand J Gastroenterol . 2009 ; 44 ( 4 ): 431 ± 40 . Epub 2008/12/23. https://doi.org/10.1080/00365520802600961 PMID: 19101844 .
40. Corrigendum . Alimentary pharmacology & therapeutics. 2015 ; 42 ( 11 ±12): 1334 . Epub 2015/10/30. https://doi.org/10.1111/apt.13425 PMID: 26510547 .
41. Safroneeva E , Vavricka S , Fournier N , Seibold F , Mottet C , Nydegger A , et al. Systematic analysis of factors associated with progression and regression of ulcerative colitis in 918 patients . Alimentary pharmacology & therapeutics . 2015 ; 42 ( 5 ): 540 ± 8 . Epub 2015/07/08. https://doi.org/10.1111/apt.13307 PMID: 26148503 .
42. Rinawi F , Assa A , Hartman C , Mozer Glassberg Y , Nachmias Friedler V , Rosenbach Y , et al. Long-term Extent Change of Pediatric-Onset Ulcerative Colitis . Journal of clinical gastroenterology . 2017. Epub 2017 /01/10. https://doi.org/10.1097/mcg.0000000000000741 PMID: 28067753 .
43. Sahami S , Konte K , Buskens CJ , Tanis PJ , Lowenberg M , Ponsioen CJ , et al. Risk factors for proximal disease extension and colectomy in left-sided ulcerative colitis . United European gastroenterology journal . 2017 ; 5 ( 4 ): 554 ± 62 . Epub 2017/06/08. https://doi.org/10.1177/2050640616679552 PMID: 28588887 .
44. Sandborn WJ , Landers CJ , Tremaine WJ , Targan SR . Association of antineutrophil cytoplasmic antibodies with resistance to treatment of left-sided ulcerative colitis: results of a pilot study . Mayo Clinic proceedings . 1996 ; 71 ( 5 ): 431 ± 6 . Epub 1996/05/01. https://doi.org/10.1016/S0025- 6196 ( 11 ) 64083 - 4 PMID: 8628021 .
45. Vecchi M , Bianchi MB , Sinico RA , Radice A , Meucci G , Torgano G , et al. Antibodies to neutrophil cytoplasm in Italian patients with ulcerative colitis: sensitivity, specificity and recognition of putative antigens . Digestion . 1994 ; 55 ( 1 ): 34 ± 9 . Epub 1994/01/01. https://doi.org/10.1159/000201120 PMID: 8112495 .
46. Seow CH , Newman A , Irwin SP , Steinhart AH , Silverberg MS , Greenberg GR . Trough serum infliximab: a predictive factor of clinical outcome for infliximab treatment in acute ulcerative colitis . Gut . 2010 ; 59 ( 1 ): 49 ± 54 . Epub 2009/08/05. https://doi.org/10.1136/gut. 2009 .183095 PMID: 19651627 .
47. Papp M , Norman GL , Vitalis Z , Tornai I , Altorjay I , Foldi I , et al. Presence of anti-microbial antibodies in liver cirrhosisÐa tell-tale sign of compromised immunity? PLoS One . 2010 ; 5 ( 9 ): e12957 . Epub 2010 / 10/05. https://doi.org/10.1371/journal.pone.0012957 PMID: 20886039 .
48. Navaneethan U. Hepatobiliary manifestations of ulcerative colitis: an example of gut-liver crosstalk . Gastroenterology report . 2014 ; 2 ( 3 ): 193 ± 200 . Epub 2014/06/22. https://doi.org/10.1093/gastro/gou036 PMID: 24951514 .
49. Lakatos L , Lakatos PL . Management of inflammatory bowel diseases in Eastern Europe . Postgraduate medical journal . 2006 ; 82 ( 966 ): 270 ± 3 . Epub 2006/04/07. https://doi.org/10.1136/pgmj. 2005 .043901 PMID: 16597815 .