Role of children's sex in mixed mother-child lymphocyte culture reactivity.

One-way mixed mother-child lymphocyte cultures (MMCLC) 4 to 20 years after the last delivery were studied with maternal responding and children's or fathers' stimulating cells (MMFLC) in 14 multiple child families with 18 sons and 20 daughters. HLA antigen typing locus A, B, DR was performed for all family members. As reported previously for newborn cells, a significantly increased maternal response could be observed in MMCLC with male as compared to female children's stimulating cells. Although the number of cases studied was small, it seems that the increased stimulating effect of male children's cells could also be observed when MMCLC values from children of different sex, and identical A,B,DR haplotypes were compared. In contrast to this, A,B,DR haploidentical children of the same sex seem to have a similar stimulating effect on the maternal response in MMCLC. The results suggest that male children's Y-chromosome-correlated minor histocompatibility antigens may additionally stimulate the maternal immune response in MMCLC.