Fetal immune response following congenital toxoplasmosis.

Serum concentrations of IgA, its subgroups IgA1 and IgA2, IgM, IgG, and IgD were determined in a group of 14 mothers who contracted toxoplasmosis during pregnancy and their 14 offspring. Four newborns developed toxoplasmosis, 10 did not. The 4 infants with congenital toxoplasmosis had evidence of increased immunoglobulin synthesis in utero in sharp contrast to the 10 offspring of toxoplasmosis-infected mothers who failed to develop the disease. Three of these 4 affected children had elevated IgM levels; all 4 had significantly increased IgA values. The use of IgA subclass IgA1 and IgA2 was not helpful in distinguishing infants with congenital toxoplasmosis from unaffected infants. The present series is consistent with other studies from this laboratory, indicating that the fetal immune response to intrauterine infection may include IgA as well as IgM.