Intrauterine viral infection and the cell-mediated immune response.

In 8 of 23 infants with congenital central nervous system (CNS) anomalies, we observed an increased cell-mediated immune (CMI) response (lymphocyte blastogenesis) to one of six simultaneously tested viral antigens, without detection of concomitant elevation in humoral antibody to that virus. These data suggest possible intrauterine viral exposure in a significant number of anomalous infants and a possible role of that exposure in the pathogenesis of congenital CNS anomalies. The CMI response may offer another approach to the identification of etiologic agents of a significant number of birth defects.