Prognostic value of cerebrospinal fluid IgA and IgG in multiple sclerosis

IgA antibodies do not activate complement and may compete with and protect against myelin degradation caused by IgM and IgG in multiple sclerosis (MS). We retrospectively evaluated cerebrospinal fluid (CSF) IgA and IgG (as indices and extended indices) from 1980 to 1988 in 68 patients with definitive MS. Sixty-one of them had survived since the time of sampling (11-19 years). IgA Extended Index was significantly higher for surviving patients (median 0.65) than for the dead patients (median 0.33). CSF IgA or IgG indices did not correlate with disability, walking distance, or time from onset of symptoms to the need of walking aid. The retrospective experimental design allowed an unusually long follow-up time, but it also had the disadvantages of such a study. Thus the results warrant a prospective study to verify the prognostic vale of CSF IgA in MS.