Effect of antiepileptic drugs on serum and salivary IgA.

IgA, IgG, and IgM concentrations were determined in sera from 100 patients under treatment for epilepsy for at least 6 months. Low IgA was found in 25% of adult sera and in an even larger percentage of sera from children. IgM concentrations were also low, whereas there was no significant difference in the IgG concentrations compared with normal sera. IgA values were normal in untreated patients but fell during treatment with phenytoin, in one patient from 1.5 to 0.2 mg/ml within 2 months. Low or undetectable salivary IgA was a common finding, especially in gingival hyperplasia.