Anti-IgA antibodies in epileptic patients with a low serum IgA concentration.

Sera from 22 phenytoin-treated epileptic patients with a serum IgA less than 0.30 g/l were examined for anti-IgA antibodies using an ELISA. Only one patient had a complete IgA deficiency. Anti-IgA antibodies of restricted specificity were detected in serum from two of the patients. Their serum IgA concentrations were 0.03 and 0.27 g/l. The serum concentrations of IgM, IgG and the IgG subclasses were normal in both these patients. The frequency of this type of anti-IgA antibody is not higher in epileptic patients with a low serum IgA than in healthy controls, and class-specific anti-IgA antibodies are not a pathogenetic factor in the IgA deficiency occurring in epilepsy.