IgG reactivity against citrullinated myelin basic protein in multiple sclerosis

An increased level of citrullinated myelin basic protein (MBP-C8) has been reported in the brains of multiple sclerosis (MS) patients. However, the in volvement of the immune response to post-translational modified MBP in the pathophysiology of MS remains speculative. The aim of this study was to com pare the levels of immunoglobulin G antibodies to several MBP epitopes, bef ore and after citrullination, in the cerebrospinal fluid (CSF) and sera of MS patients using enzyme-linked immunosorbent assay (ELISA). We analyzed an tibody reactivity against various MBP-peptides in the CSF and sera of 60 MS patients, and 30 patients with other neurological diseases (OND) as contro ls. The peptides tested were: MBP75-98 (peptide 1), native (peptide 2) and citrullinated (peptide 3) MBP108-126 (ARG(122) --> Cit(122)), and native (p eptide 4) and citrullinated (peptide 5) MBP151-170 (ARG(159,170) --> Cit(15 9,170)). All selected peptides could support an immune reactivity in CSF an d sera of MS and OND patients. A higher reactivity against peptide 4 was fo und in the CSF of MS patients compared with OND patients (P < 0.0001), but not against citrullinated peptides (peptides 3 and 5). However, we observed that the citrullination state of peptide 2 modified the patterns of immune reactivity more markedly in MS patients (P < 0.0001) than in OND patients (P < 0.02). Although some MBP epitopes could be a potential target in MS, o ur data did not demonstrate any difference of antibody response to ME P pep tides in their citrullinated forms. (C) 2001 Elsevier Science B.V. All righ ts reserved.