Mixed Lymphocyte Reaction and Placentation

Abstract

THE duration of survival of an allograft is influenced by the degree of tissue genetic disparity between donor and recipient. This disparity can, to a limited extent, be defined by comparison of the histocompatibility antigens on the surface of lymphocytes from donor and recipient. Knowledge of these so-called HL-A antigens is, however, incomplete and because of this HL-A typing is of limited value in assessing histocompatibility. The mixed lymphocyte culture reaction can be used as an in vitro model of cell mediated immune reactions¹. The degree of reactivity correlates with the difference across strong transplantation antigens². Reactivity in mixed lymphocyte cultures may reflect more completely the tissue genetic disparity between cell donors than comparison of HL-A type. The foetus in human pregnancy may be thought of as an allograft and, as such, histocompatibility differences between it and the maternal host might influence graft survival. Animal experiments have indicated that greater histocompatibility differences between mother and conceptus may be associated with larger placentae. We have studied the relationship of reactivity in mixed leucocyte cultures of cells from mothers and their babies at delivery to placental weight.