Serological Studies on Lymphocytotoxic Antibodies in Primiparous Women

24 sera from primiparous women were studied. The HL—A phenotypes of both husbands and wives were determined in 21 cases out of 24. A comparative study was performed between the specificity of the antibodies detected and that of the antibodies expected from the husband's HL—A phenotype. In 4 cases, the specificity of the antisera could not be defined. In 8 cases, the antisera contained a single antibody directed against a single HL—A antigen. In 12 cases, the specificities of the antibodies were broader than expected. In 3 cases, antibodies were detected against an antigen of a given cross‐reacting group (CREG) in women already carrying an antigen belonging to the same CREG. They concerned two anti‐HL—A2 antibodies detected in woman carrying Da15 (W28) antigen and an anti‐FJH antibody in a woman carrying an HL—A7 antigen. The strength of the sera from primiparous women was compared with that of sera from multiparous women. No significant difference was observed between the two groups of sera. The persistence of antibodies is variable: some antibodies disappear within less than 17 weeks after delivery; some others remain present for over 4 years.