IgA deficiency, epilepsy, and phenytoin treatment

Area of Science:

• Immunology
• Pediatric Neurology
• Pharmacology

Background:

• Immunoglobulin A (IgA) deficiency is a common primary immunodeficiency.
• Phenytoin (diphenylhydantoin) is an anticonvulsant medication used to treat seizures.
• Febrile seizures in infancy are a common childhood neurological event.

Purpose of the Study:

• To investigate the effect of phenytoin treatment on serum immunoglobulin A (IgA) levels in children with seizures.
• To explore the potential mechanism by which phenytoin might influence IgA production.

Main Methods:

• Prospective study of 32 children with seizures treated with phenytoin.
• Measurement of serum IgA levels before and during 6 months of treatment.
• Analysis of lymphocyte populations with surface IgA in treated children with low IgA levels.

Main Results:

• Five of 32 children had low serum IgA before phenytoin treatment, primarily those with a history of febrile convulsions.
• Serum IgA levels significantly decreased in 14 patients during 6 months of phenytoin therapy.
• Children with low IgA on phenytoin treatment had normal numbers of B lymphocytes expressing surface IgA.

Conclusions:

• Phenytoin treatment may lead to a decrease in serum IgA levels in children.
• The findings suggest phenytoin could impair the terminal differentiation of B lymphocytes.
• This impairment represents a potential novel cause for common immunoglobulin deficiency.