Influence of Foetal A and B Blood‐Group Substances on the Immunization of Pregnant Women¹

Abstract

Laboratory (Chief: F. Kissmeyer-Nielsen, M.D.), k h u s Kommunehospital, and State Maternity Hospital for Jutland (Chief: Professor M. Ingerslev, M.D.), Arhus R h immunization of pregnant women is assumed t o occur through the passage of foetal erythrocytes into the circulation of the mother. The R h antigens are presumably present only in the erythrocytes in alcohol-soluble form [l]. The presence of R h antigens outside the erythrocytes is questionable [ll]. ABO immunization may also occur through the passage of foetal red cells across the placental barrier, but unlike the R h antigens, the ABO antigens are present outside the erythrocytes in large quantities in tissues and tissue fluids not only in alcohol-soluble form but also in water-soluble form. Various observations support the assumption that the foetal water-soluble A and B blood-group substances are of significance for the immunization of pregnant women. The A and B blood-group substances causing ABO immunization may originate from the serum of the foetus or from the amniotic fluid. Specific blood-group substance in the serum can be demonstrated in the majority of new-born infants of groups A, B and AB.Secretors have a little more substance than non-secretors, but the difference is slight [8]. The amniotic fluid also contains specific bloodgroup substance when the foetus is group A, B or AB [17, 191. FREDA [7] showed that the occurrence in the amniotic fluid depended on the secretor properties of the foetuses, since when the mother was a non-secretor, the amniotic fluid contained either no blood-group substance or a t the most only traces. Aided by grants from Kebmand i Odense Johann og Hanne Weimann f. Seedorffs Legat and Girdejer P. L. Pedersens Legat.

Lewis and ABH Substances in Amniotic Fluid Obtained by Amniocentesis

“…That there was possible maternal contribution to the ABH blood group activity of the amniotic fluid in some cases have been reported [4,6,7]. Freda [4] found in his study that only when the mother was a secretor could her blood group substances be found in the amniotic fluid.…”

“…Both Freda [4] and Hostrup [6] found ABH substances in the amniotic fluids of both secretor and nonsecretor infants; however, the concentration was higher among their infants who were secretors. In Hostrup's study [6], this was true for all his cases of ABO-homospecific motherinfant pairings in which at least one of the pair was a secretor. As pointed out earlier, in ABO-homospecific mother-infant pairs in which both are secretors, there is no way to determine whether the ABH blood group substance present in amniotic fluid is fetal and/or maternal in origin.…”

“…Freda [4] found in his study that only when the mother was a secretor could her blood group substances be found in the amniotic fluid. Hostrup [6] reported maternal blood group substances in the amniotic fluid of some mothers who were secretors but not in all cases, and thus suggested that the presence of maternal blood group substances could have been due to contamination of the amniotic fluid during sampling. Both Freda [4] and Hostrup [6] found ABH substances in the amniotic fluids of both secretor and nonsecretor infants; however, the concentration was higher among their infants who were secretors.…”

“…Hostrup [6] reported maternal blood group substances in the amniotic fluid of some mothers who were secretors but not in all cases, and thus suggested that the presence of maternal blood group substances could have been due to contamination of the amniotic fluid during sampling. Both Freda [4] and Hostrup [6] found ABH substances in the amniotic fluids of both secretor and nonsecretor infants; however, the concentration was higher among their infants who were secretors. In Hostrup's study [6], this was true for all his cases of ABO-homospecific motherinfant pairings in which at least one of the pair was a secretor.…”

“…Although the soluble blood group substances A, B, and H are known to be present in amniotic fluid at the time of delivery [4,6,10] and as early as 9-24 weeks of gestation [5], the presence of Lewis substances in amniotic fluid at any stage of pregnancy has not been previously studied. In this report, we present our results from semiquantitative measurements of Lewis substances Le a , Le b , and Le x and of ABH in amniotic fluid obtained by amniocentesis at different stages of gestation.…”