Lymphocyte abnormalities in infants born to drug-abusing mothers.

To evaluate the possible effects of maternal intravenous drug use on infant immunity, we measured the in vitro peripheral blood mononuclear cell proliferative responses to phytohemagglutinin (PHA) and pokeweed mitogen, T cell subset numbers, immunoglobulin levels, and titers of antibodies to cytomegalovirus (CMV) and human immunodeficiency virus (HIV) in a group of drug-abusing mothers and their infants. Infants of drug abusers had a lower proliferative response to mitogen, associated with altered kinetics of the maximum response to PHA. The OKT4/OKT8 ratio decreased with age in the drug-exposed infants compared with control infants (P less than 0.005). There was no evidence of CMV infection in either group. One mother and her infant had antibody to HIV. Our data demonstrate that infants of intravenous drug-using mothers have distinct immunologic differences at birth compared with non-drug-exposed infants and that these persist throughout the first year of life. The cause appears unrelated to intrauterine viral infection, suggesting a direct toxic effect of the drugs on fetal immunologic development.