Impaired cellular immunity to rubella virus in congenital rubella.

Specific cell-mediated immunity (CMI) responses to rubella virus were studied in 12 children with documented congenital rubella syndrome employing a (51)Cr lymphocytotoxicity microassay. Hemagglutination inhibition antibody was detected in 11 of the 12 children, with titers ranging from 1:4 to 1:128. CMI to rubella virus was demonstrated in only 3 of the 11 antibody-positive children. The 12th child was negative for both hemagglutination inhibition and CMI. Of the three children with a positive CMI response, two had histories of reinfection with rubella virus. These data suggest that congenital rubella infection produces an impaired CMI response which subsequently may be altered by reinfection with rubella virus. The lack of CMI in the presence of antibody and concurrent excretion of live virus in the child with documented congenital rubella infection suggest a factor to be explored in the pathogenesis of this disease.