Phenytoin-induced depression of salivary IgA and gingival hyperplasia.

IgA concentrations were determined in saliva from epileptic patients taking phenytoin and in saliva from healthy controls, by single radial immunodiffusion technique. Mean salivary IgA in epileptic children was 7.23 mg/ml; in healthy children, 16.44 mg/ml. Corresponding values for adults were 13.53 and 19.48 mg/ml, respectively. In 14 out of 84 samples, salivary IgA levels were too low for quantitative analysis. Salivary IgA levels were normal in untreated patients and fell during treatment with phenytoin. Gingival inflammation was commonly accompanied by an increase of salivary IgG and serum-derived IgA, whereas compensatory increase of IgM was infrequent. Phenytoin-induced deficiency of salivary IgA can result in increased susceptibility to gingival inflammation, which is considered one of the predisposing factors for subsequent development of gingival hyperplasia.