MULTIPLE-SCLEROSIS AND INTRATHECAL IGA SYNTHESIS

A clinically definite diagnosis of multiple sclerosis was done in a 61 year-old woman who displayed severe cerebellar and pyramidal tract in volvement. Symptoms developed 5 years before with unsteadiness of gait and difficulties in walking. Diagnosis was supported by evoked potent ials studies and magnetic resonance imaging. However, the cerebrospina l fluid (CSF) analysis was very unusual. CSF albumin and IgG concentra tion were normal, as well as the IgG index. In contrast, the IgA level and the IgA index were markedly increased and the local synthesis of IgA was estimated at 31.36 mg/l. Reduction by dithiotreitol did not ch ange the IgA level. On affinity immunoblots, oligoclonal IgG bands wer e not detected but oligoclonal IgG bands were present. The strong loca l production of IgA in this patient seems to be therefore polyclonal.