Transient phenytoin induced IgA deficiency and permanent IgE increase

This is a report of a 9-year-old epileptic boy, who was studied over a period of 7 years. The seizures started when he was 2 months old. He was treated with phenytoin from the age of 2 years and 7 months. Serum and salivary IgA were absent with high IgE serum total. The routine immunologic studies were normal. The IgA was normalized after phenytoin withdrawal, but IgE determination increased progressively without any atopic symptoms. The T4 (helper)/T8 (suppressor) ratio decreased (1.0 and 1.2) on two different days, although above the normal limit. The phenytoin only modified the IgA levels. These data suggest that a primary immunoregulatory abnormality may be present in drug induced IgA deficiency.