INTERACTION BETWEEN ABO BLOOD-GROUPS AND ADA GENETIC-POLYMORPHISM DURING INTRAUTERINE LIFE - A COMPARATIVE-ANALYSIS OF COUPLES WITH HABITUAL ABORTION AND NORMAL PUERPERAE DELIVERING A LIVE-BORN INFANT

A total of 203 couples with unexplained habitual abortions and 364 con secutive normal puerperae along with their live-born babies were studi ed. The analysis of wife-husband joint ABO blood group distribution in couples with habitual abortion showed an excess of A incompatible mat ing type and a defect of B incompatible type as compared with expected proportions assuming random mating. The joint wife-husband ABO blood group distribution was further analysed in relation to the adenosine d eaminase (ADA) genotype. A defect of O-A and A-O couples when the wife carries the ADA1/*1 genotype and the husband carries the ADA*2 allel e, and a defect of O-O and A-A when the wife carries the ADA2 allele were observed. In the sample of normal puerperae, analysis of the join t mother-newborn ABO distribution in relation to the ADA genotype show ed a pattern similar to that observed in couples with habitual abortio n, i.e. there is a defect of O-A and A-O when the mother carries the A DA1/*1 genotype and the newborn carries the ADA*2 allele and a defect of O-O and A-A types when the mother carries the ADA2 allele. Altoge ther the data suggest an early loss of O-A and A-O zygotes when they c arry the ADA2 allele and an early loss of O-O and A-A zygotes when th e mother carries the ADA2 allele resulting in a deficit of these zygo tic classes among both spontaneously aborted fetuses and live-born inf ants, The pattern of association observed in the mother-fetus type O-A (incompatible according to conventional terminology) appears similar to that observed for the reciprocal A-O type (compatible according to conventional terminolgy). Therefore strictly conventional immunologica l mechanisms cannot explain the whole pattern of associations. Cell to cell interactions involving ABO antigens may have an important role a t implantation: ADA, through the control of local adenosine concentrat ion, could modulate these interactions influencing the probability of successful implantation.