Cerebrospinal fluid detection of interleukin-1β in phase of remission predicts disease progression in multiple sclerosis

Silvia Rossi 0 1 3 4 Valeria Studer 0 1 3 4 Caterina Motta 0 1 3 4 Giorgio Germani 0 1 3 4 Giulia Macchiarulo 0 1 3 4 Fabio Buttari 0 1 3 4 Raffaele Mancino 2 Maura Castelli 0 1 3 4 Valentina De Chiara 0 1 3 4 Sagit Weiss 0 1 3 4 Gianvito Martino 5 Roberto Furlan 5 Diego Centonze 0 1 3 4 0 Fondazione Santa Lucia/Centro Europeo per la Ricerca sul Cervello (CERC) , Via del Fosso di Fiorano 64, 00143 Rome , Italy 1 Clinica Neurologica, Dipartimento di Medicina dei Sistemi, Universita Tor Vergata , Via Montpellier 1, 00133 Rome , Italy 2 Clinica Oculistica, Dipartimento di Medicina Sperimentale e Chirurgia, Universita Tor Vergata , Via Montpellier 1, 00133 Rome , Italy 3 Fondazione Santa Lucia/ Centro Europeo per la Ricerca sul Cervello (CERC) , Via del Fosso di Fiorano 64, 00143 Rome , Italy 4 Clinica Neurologica, Dipartimento di Medicina dei Sistemi, Universita Tor Vergata , Via Montpellier 1, 00133 Rome , Italy 5 Neuroimmunology Unit, Institute of Experimental Neurology (INSpe), Division of Neuroscience, San Raffaele Scientific Institute , Via Olgettina 58, 20132 Milan , Italy Background: Absence of clinical and radiological activity in relapsing-remitting multiple sclerosis (RRMS) is perceived as disease remission. We explored the role of persisting inflammation during remission in disease evolution. Methods: Cerebrospinal fluid (CSF) levels of interleukin 1 (IL-1), a major proinflammatory cytokine, were measured in 170 RRMS patients at the time of clinical and radiological remission. These patients were then followed up for at least 4 years, and clinical, magnetic resonance imaging (MRI) and optical coherence tomography (OCT) measures of disease progression were recorded. Results: Median follow-up of RRMS patients was 5 years. Detection of CSF IL-1 levels at the time of remission did not predict earlier relapse or new MRI lesion formation. Detection of IL-1 in the CSF was instead associated with higher progression index (PI) and Multiple Sclerosis Severity Scale (MSSS) scores at follow-up, and the number of patients with sustained Expanded Disability Status Scale (EDSS) or Multiple Sclerosis Functional Composite worsening at follow-up was higher in individuals with detectable levels of IL-1. Patients with undetectable IL-1 in the CSF had significantly lower PI and MSSS scores and a higher probability of having a benign MS phenotype. Furthermore, patients with undetectable CSF levels of IL-1 had less retinal nerve fiber layer thickness and macular volume alterations visualized by OCT compared to patients with detectable IL-1. Conclusions: Our results suggest that persistence of a proinflammatory environment in RRMS patients during clinical and radiological remission influences midterm disease progression. Detection of IL-1 in the CSF at the time of remission appears to be a potential negative prognostic factor in RRMS patients. - Background Relapsingremitting multiple sclerosis (RRMS) was originally described as a disease characterized by alternating symptomatic and asymptomatic periods, which were perceived to reflect, respectively, disease activity and remission. With the advent of conventional and, later, unconventional magnetic resonance imaging (MRI) technologies, it appeared that the disease could be active in asymptomatic patients, leading to an extension of diagnostic criteria for RRMS and response to treatment to radiological parameters. Hints suggesting that disability in RRMS patients has additional causes beyond clinical and radiological relapses came from observations in patients with brain atrophy and reduction of N-acetyl aspartate, a marker for axonal loss. Brain atrophy appeared to progress in patients who were not active [1], whereas brain atrophy progression [2] and reduction of N-acetyl aspartate [3] correlated with disability progression, indicating that disease severity was not determined by relapses only. In line with these observations, researchers who have conducted pathological studies have reported synapse, neuronal and glial loss independent of demyelination [3-9]. Further, investigators have reported evidence of neuronal and glial excitotoxicity in MS [10-12], a central nervous system (CNS)specific cellular death pathway triggered by an excess of excitatory glutamate signaling. In this respect, we have recently demonstrated that, during MS relapses, cerebrospinal fluid (CSF) concentrations of the proinflammatory cytokine interleukin 1 (IL-1) increase to a level high enough to boost excitatory transmission and excitotoxic damage in neurons [13]. These premises prompted us to explore whether persistence of IL-1 signaling during remission phases of MS could affect the severity of the disease. In accord with this hypothesis, our results show that detection of the proinflammatory cytokine IL-1 in the CSF of early RRMS patients at the time of remission was associated with pronounced neuronal damage and accumulating disability in the following years. Methods This study was conducted in compliance with the principles of the Declaration of Helsinki and was approved by the Ethical Committee of the Policlinico Universit Tor Vergata in Rome. All the participants gave their written informed consent to be included in the study. Multiple sclerosis patients and cerebrospinal fluid collection A total of 170 central-southern Italian subjects with a diagnosis of RRMS according to the 2005 McDonald criteria [14] were included in this study (Figure 1). CSF was collected at the time of diagnosis from patients in clinical and radiological remission. In particular, patients who had experienced a clinical relapse within the preceding 60 days or had shown gadolinium (Gd)-enhanced lesions or new lesions visualized by T2-weighted MRI were excluded. Relapses were defined as the development of new or recurrent neurological symptoms not associated with fever or infection lasting for at least 24 hours. Lumbar puncture and brain MRI were performed within 24 hours of each other. Blood sample collection, CSF withdrawal and clinical assessments were performed at the MS Center of the Tor Vergata University Hospital of Rome by MS specialist neurologists. To be recruited into the study, patients had to have had at least 4 years of clinical, MRI and optical coherence tomography (OCT) follow-up after CSF collection. In addition, only patients clinically in the remitting phase of MS and without MRI evidence of new or active lesions at the time of CSF withdrawal were considered for inclusion in the present investigation. Accordingly, only transient elevation of proinflammatory cytokines has been reported during MRI or clinical reactivation in MS patients [13,15]. Demographic and clinical information were derived from medical records. MS disease onset was defined as the first episode of focal neurological dysfunction indicative of MS. Disease duration was estimated as the number of years from onset to the most recent assessment of disability. The Bayesian Risk Estimate for M (...truncated)