INTRATHECAL SYNTHESIS OF VIRUS-SPECIFIC OLIGOCLONAL IGG, AND OF FREE KAPPA-OLIGOCLONAL AND FREE LAMBDA-OLIGOCLONAL BANDS IN ACUTE MONOSYMPTOMATIC OPTIC NEURITIS - COMPARISON WITH BRAIN MRI

Twenty-seven patients with acute monosymptomatic optic neuritis were r andomly selected from a population-based cohort of patients extensivel y screened for known etiologies of ON. Paired serum and CSF obtained m edian 20 days from onset were examined for oligoclonal IgG, free kappa and free lambda chains, and virus-specific oligoclonal IgG antibodies by on affinity-mediated capillary blot technique. CSF-restricted olig oclonal IgG bonds, free kappa and free lambda chain bonds were observe d in 17, 15 and nine patients, respectively In addition, 16 patients s howed a polyspecific intrathecal synthesis of oligoclonal IgG antibodi es against one or more viruses (12 measles, nine varicella tester, six rubella, six mumps) compared to all the 18 examined patients with def inite multiple sclerosis (P=0.0014). The presence of virus-specific ol igoclonal IgG was significantly related to the results of oligoclonal IgG (P=0.0034), free kappa chain bonds (P=0.0020), and brain MRI abnor malities (P=0.0402). At 1 year follow-up five patients had developed c linically definite multiple sclerosis; all had virus-specific oligoclo nal IgG antibodies, oligoclonal IgG and abnormal MRI at onset.