INFLUENCE OF HISTOCOMPATIBILITY ANTIGENS IN RECURRENT SPONTANEOUS-ABORTION COUPLES AND ON THEIR REPRODUCTIVE PERFORMANCES

PROBLEM: To determine if human leukocyte antigens (HLA) play any role in the aetiology of recurrent spontaneous abortion (RSA), a substantia l group of RSA couples were studied, and their reproductive performanc es in a 3-year follow-up recorded. METHODS: HLA typing was performed f or HLA-A, -B, and DR antigens in both partners of 75 couples with unex plained RSA, and compared with a control group of 30 fertile couples t hat never experienced abortion. A further 57 couples of this group wer e studied for their reproductive performance in a 3-year follow-up, an d subdivided into three subgroups: 1) couples that achieved successful pregnancy during the follow-up; 2) couples that experienced abortion and no livebirth during the follow-up; and 3) couples that experienced infertility during the follow-up. RESULTS: There were no significant differences for antigen frequency in all the different HLA loci, and H LA antigen sharing between all the RSA couples and controls. Significa nt increase of sharing for HLA-DR locus was observed in the couples th at aborted during the follow-up with respect to the couples that achie ved livebirth and controls (P < 0.03 and P < 0.02 respectively), and s ignificantly increased frequency of B44, DR5 antigen combination in th e same comparison (P < 0.03). No significant differences were observed in terms of the interval between conceptions in couples without antig en sharing with respect to couples with 1, 2 or more antigens shared, and antigen sharing in Locus A, B or DR. CONCLUSIONS: The results sugg est that gene(s) disadvantageous for reproduction may exist between th e HLA-B and -DR chromosomal region which influences the pregnancy outc ome in RSA couples, and that HLA-antigen sharing itself does not influ ence the outcome.