Adult reference intervals for IgG subclasses with Siemens immunonephelometric assays in Chinese population

Allergy, Asthma & Clinical Immunology, Oct 2017

To determine the adult reference intervals for the Siemens IgG subclass reagents. 636 blood samples of healthy adults were analyzed to determine the level of IgG subclass using the reagents of Siemens immunonephelometric assay with molecular biology kits. IgGSc reference intervals were as follows: IgG1 4.45–9.76 g/L, IgG2 2.07–8.57 g/L, IgG3 0.08–0.80 g/L and IgG4 0.05–1.54 g/L. There was an excellent correlation between the total IgG and the sum of the IgG subclasses. No significant gender and age differences were observed. Our data provide the missing reference intervals and enable the use of the nephelometric IgG subclass reagents in Chinese. The study can offer reference on clinic diagnose.

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Adult reference intervals for IgG subclasses with Siemens immunonephelometric assays in Chinese population

Li et al. Allergy Asthma Clin Immunol Adult reference intervals for IgG subclasses with Siemens immunonephelometric assays in Chinese population Ping Li 0 Zhongjuan Liu 1 Ziyan Wu 0 Xiaoting Wen 0 Liubing Li 0 Shulan Zhang 0 Yingchun Xu 1 Yongzhe Li 0 0 Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing 100730 , China 1 Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Beijing 100730 , China Objective: To determine the adult reference intervals for the Siemens IgG subclass reagents. Methods: 636 blood samples of healthy adults were analyzed to determine the level of IgG subclass using the reagents of Siemens immunonephelometric assay with molecular biology kits. Results: IgGSc reference intervals were as follows: IgG1 4.45-9.76 g/L, IgG2 2.07-8.57 g/L, IgG3 0.08-0.80 g/L and IgG4 0.05-1.54 g/L. There was an excellent correlation between the total IgG and the sum of the IgG subclasses. No significant gender and age differences were observed. Conclusions: Our data provide the missing reference intervals and enable the use of the nephelometric IgG subclass reagents in Chinese. The study can offer reference on clinic diagnose. Immunoglobulin subclasses; Immunonephelometric assays; Chinese population Background Four distinct heavy chain subgroups of human IgG were first demonstrated in the 1960s by using polyclonal antisera prepared in animals immunized with human myeloma proteins [ 1, 2 ]. Since then, determination of selective immunoglobulin subclasses (IgGSc) has become an established tool in the diagnosis of many diseases, such as immunologic deficiencies and adult IgG4-related disease (IgG4-RD) [ 3, 4 ]. Recurrent respiratory tract infections that are poorly responsive to antibiotics are common presentations of immunoglobulin (Ig) deficiency in adults and children. There is a group of patients with similar clinical presentation, but who have serum IgG levels within or close to the bottom of the normal range and in whom one or more of the IgG subclasses 1–4 is entirely lacking or present in greatly reduced amounts [ 5, 6 ]. IgG4-RD is a recently recognized fibroinflammatory condition that has tumefactive lesions, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, and this disease is typically associated to an increase of serum IgG4 level. Serum IgG4 elevation becomes from this date a biological marker of IgG4-RD, and serum IgG4 elevation (> 1.35 g/L) is considered as a diagnosis criteria for IgG4RD [ 7, 8 ]. The immunonephelometric determination of IgG subclasses in serum is based upon the specific reaction of the respective human IgG subclass with a polyclonal (mono) specific, highly avid anti-IgG subclass antiserum. Immunonephelometric assays were designed for fast, fully automated and specific quantification of human IgG subclasses profile (IgG1, IgG2, IgG3 and IgG4). Although more and more serum IgG subclasses assays were performed by the Dade Behring IgG subclass reagents (Siemens Healthcare Diagnostics Products GmbH BN™) in China, a limitation of IgGSc is the lack of larger cohorts providing populational serum concentration measurements in order to establish normal reference values, and published reference intervals are limited to a certain geographical area. Therefore, the purpose of this study was to assess IgGSc reference intervals in healthy, mostly Chinese adults, using fully automated and reproducible immunonephelometric assays. We performed the whole experiment process according to the test method recommended by Clinical and Laboratory Standards Institute (CLSI) [ 9 ]. Methods Information of the recruited subjects The study population included 636 clinically healthy adults (309 males and 327 females) from 18 to 85  years of age who were admitted to Peking Union Medical College Hospital for health physical examination. Good health was confirmed by a clinical questionnaire and blood parameters within reference intervals. The serum was frozen within less than 4 h in sterile at −80 °C until measurement. All specimens included for analysis were the first received on each patient during the period, duplicates being excluded. The study was approved by the ethics committee of the Peking Union Medical College hospital and all subjects gave informed consent. Measurements of reference intervals All IgGSc were measured by nephelometry according to the manufacturer’s instructions (BN2 nephelometer, Dade Behring GmbH, Marburg, Germany). The inter-assay coefficients of variation (CV) are 1.9–5.3% with total CV of 2.6–6.2%. We used the following concentrations for the CVs: Level SL-H: IgG1  =  7.33  g/L, IgG2  =  3.87  g/L, IgG3  =  0.482  g/L, IgG4  =  0.779  g/L; for Level SL-L: IgG1  =  3.78  g/L, IgG2  =  1.94 (...truncated)


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Ping Li, Zhongjuan Liu, Ziyan Wu, Xiaoting Wen, Liubing Li, Shulan Zhang, Yingchun Xu, Yongzhe Li. Adult reference intervals for IgG subclasses with Siemens immunonephelometric assays in Chinese population, Allergy, Asthma & Clinical Immunology, 2017, pp. 44,