Immunoglobulin concentrations in first-degree relatives of epileptic patients with drug-induced IgA deficiency.

Serum immunoglobulins A, G and M were studied in parents and siblings of 16 patients being treated for epilepsy. Five healthy families served as controls. Seven of the patients were low IgA-responders and the rest of the patients had shown normal IgA-levels during treatment. None of the parents and siblings studied showed a serum-IgA deficiency, with the exception of one mother who was being treated for rheumatoid arthritis with naproxen. Low serum concentrations of IgG and IgM were not found. A significantly increased IgM-level was found in first-degree relatives of the low IgA-responders, and the siblings of low 2gA-responders had significantly raised IgA in their sera.