The HLA antigens in women with recurrent abnormal pregnancies of unknown etiology

HLA allele associations in idiopathic recurrent spontaneous abortion patients from India

BACKGROUND:

Rejection of semiallogenic foetus in recurrent spontaneous abortion (RSA) has been postulated to be a consequence of genetic and immunological phenomena.

AIM:

To evaluate the role of human leukocyte antigen (HLA) alleles in RSA in Indian couples.

SETTINGS AND DESIGN:

A case-control study.

MATERIALS AND METHODS:

Eighty-one randomly selected couples with unexplained three or more RSAs and a control group of 97 couples with live birth belonging to the same ethnic background, referred to the Gynaecology Department, KEM Hospital were included in the case-control study. Serological HLA A and B typing was done followed by molecular subtypes, defined using PCR-SSOP technique for HLA A, B, and C in 40 couples and DRB1* and DQB1* in 28 couples which were then compared with appropriate case 46 and 88 controls.

RESULTS:

Serologically A3 (15.43% vs. 4.43%; odds ratio (OR) = 4.34; P = 0.0002) and B17 (25.3% vs. 11.34%; OR = 3.49; P = 0.0001) were increased. Haplotype A1-B17 was significantly increased. Molecular subtyping revealed that A*030102 (11.25% vs. 4.34%; OR = 3.00; P = 0.07), B*5701 (11.25% vs. 1.08%; OR = 13.10; P = 0.003), Cw*120201 (25% vs. 4.34%; OR = 10.50; P = 2.05E-05), HLA DRB1*030101 (17.85% vs. 3.40%; OR = 7.6; P = 0.0001), DRB1*150101 (32.14% vs. 13.63%; OR = 4.8; P = 0.0003), and DQB1*060101 (35.71% vs. 29.34%; OR = 2.3; P = 0.004) were significantly increased in patients. A differential association was noticed when compared with reported world RSA patients.

CONCLUSION:

The HLA alleles A*030101, B*5701, Cw*120201, DRB1*030101, and DRB1*150101 as well as their associated ancestral haplotype may play a significant role in development of RSA in India.

HLA sharing, anti-paternal cytotoxic antibodies and MLR blocking factors in women with recurrent spontaneous abortion

OBJECTIVE

To study the prevalence of HLA sharing between spouses and its correlation with presence of antipaternal cytotoxic antibody (APCA) and mixed lymphocyte reaction (MLR) blocking factors in recurrent spontaneous aborters (RSA).

DESIGN

Study was carried out at Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGI), Lucknow, from 1988-1992. Hundred couples with 3 or more consecutive recurrent spontaneous abortions and equal number of age, parity and ethinically matched normal controls were selected for studying HLA, APCA and MLR blocking factors. Meta-analysis was performed using standard formula and significance was tested by Chi-square analysis.

RESULTS

Significant HLA sharing was observed in couples with RSA at A and DR loci compared to normal controls (p < 0.001). Twenty-seven point eight percent of couples with RSA were positive for APCA compared to 49% of controls (p < 0.01). MLR blocking factors were detected in 26% couples with RSA compared to 78% in controls (p < 0.001). An inverse correlation between HLA sharing and APCA and MLR positivity was demonstrated.

CONCLUSION

The study supports that greater HLA sharing between spouses, associated with lack of an appropriate immune response to them could be responsible for RSA.

Immunogenetic and serological investigations in nonpregnant and in pregnant women with a history of recurrent spontaneous abortions. German RSA/IVIG Study Group

In the context of a controlled multicenter study on intravenous immunoglobulin (IVIG) treatment of patients with a history of unexplained recurrent spontaneous abortions (RSA), a number of controversial immunological parameters were evaluated prior to and during pregnancy with respect to their diagnostic and/or prognostic significance. A total of 390 serum samples from 52 patients were investigated. Sharing of 2 or more HLA (A, B, DR, DQ) antigens was significantly more frequent in RSA couples than in controls. The rate of cytotoxic or Fc-receptor (FcR)-blocking antibodies was not significantly lower in RSA patients than in individuals with normal pregnancies. Both tumor necrosis factor-alpha (TNF-alpha) levels and IgG anticardiolipin antibodies (IgG-ACA) were significantly increased in the patient group. While the occurrence of HLA sharing, cytotoxic/FcR-blocking antibodies and IgG-ACA did not correlate with the outcome of pregnancy, TNF-alpha levels were found to be significantly higher in patients with subsequent miscarriage than in those with successful pregnancy. IgG-ACA, if present, significantly decreased during the course of successful pregnancy but remained high in patients with subsequent abortion. It is concluded that the diagnostic and/or prognostic value of HLA sharing and cytotoxic/FcR-blocking antibodies has been overestimated while TNF-alpha and ACA levels are potential diagnostic markers and/or exhibit prognostic significance in subgroups of RSA patients.

HLA and red blood group antigens in pregnancy disorders

Total of 356 women with various types of pregnancy disorders as well as their husbands were classified in four groups regarding the type of the disorder as follows: 1. Recurrent spontaneous abortions (RSA) of unknown etiology (N = 105) and RSA - primary aborters only (N = 84); 2. Blighted ovum (N = 80); 3. Rh immunization in pregnancy (N = 90); 4. ABO immunization in pregnancy (N = 47). Two groups of couples were used as controls: 1. Couples randomly taken from forensic medicine cases of paternity evaluation (N = 104); 2. Couples having two or more children with HLA immunization in pregnancy (N = 78). The couples from all groups were typed for red blood group antigens of ABO, Rhesus, MNSs, Kell, Duffy, Lewis, Kidd and P systems and also for HLA antigens. Significantly higher frequency of antigen HLA-A9 was found in women with RSA (corr. p = 0.0003) and in women with pregnancy disorders caused by Rh immunization (corr. p = 0.0136). In couples with RSA the degree of HLA compatibility was significant (p = 0.0048) and the reactivity of spouses in MLR was significantly decreased (p = 0.0001). Significantly, more low responders in MLR were also found among the women with RSA as compared to the controls (p = 0.0217). Two possible pathologic mechanisms may explain the association between HLA antigens and RSA: 1. immunological defects which are linked to HLA-D/DR region causing malfunction of immunosuppressive mechanisms during pregnancy; 2. endocrinological defect which is linked to HLA region as 21-OH hydroxylase deficiency gene.

Preferential transmission of diabetic alleles within the HLA gene complex

Several studies suggest a higher incidence of insulin-dependent diabetes mellitus (IDDM) among the offspring of men with the disease than among those of female diabetics. Differential transmission by the father of genes that predispose to diabetes may explain this phenomenon. To test this hypothesis, we examined parent-to-offspring transmission of HLA haplotypes and DR (D-related) alleles in 107 nuclear families in which a child had IDDM. We observed that fathers with a DR4 allele were significantly more likely to transmit this allele to their diabetic or nondiabetic children than were mothers with a DR4 allele (72.1 vs. 55.6 percent, P less than 0.001). No differences between parents were observed for HLA-DR3; however, DR3 was transmitted significantly more than 50 percent of the time from either parent (P less than 0.001). These data suggest that differential parental transmission of the HLA-DR4-linked diabetes-predisposing allele may explain the higher risk of diabetes among children of diabetic fathers than among those of diabetic mothers. In addition, the excess transmission of diabetogenic HLA alleles from parent to offspring may explain how these deleterious genes continue to recur at such high frequencies in the general population.

Probabilistic assessment of the degree of antigen sharing in couples with impaired reproductive performance

Increased histocompatibility antigen sharing has been reported in couples experiencing recurrent infertility problems. Mathematical expressions describing the probability distribution of the number of antigens shared by randomly mating couples are derived for a single locus, two linked loci, and multiple independent systems. These theoretical frequencies are applied in concert with conventional statistical procedures to evaluate hypotheses concerning antigen distributions. Extensions for simultaneous consideration of other genetic systems are discussed.

Immunologic mechanisms in the maternal-fetal relationship

Until recently, the immunologic tolerance between a mother and her allogeneic fetus has been a highly speculative and poorly understood phenomenon. New data indicate that maternal acceptance of the fetal allograft necessitates a specific, protective immune response. This specific recognition apparently involves unique placental antigens with genes that are closely linked to HLA loci. Lack of recognition of these antigens, as in matings between partners with similar HLA profiles, may result in repeated spontaneous abortions caused by unsuppressed rejection mechanisms.

Histocompatibility in Italian couples with recurrent spontaneous abortions of unknown origin and with normal fertility

We investigated HLA antigen and haplotype frequencies in 47 couples with primary recurrent abortions of unknown origin, in 65 fertile couples, and in a control panel of 98 males and 92 females. A significant increase of HLA-B17 was found in abortion couples in comparison with fertile couples. No difference between abortion and control fertile couples was observed regarding HLA sharing.

HLA-DR locus and maternal-foetal relation

Antigen HLA-A, B sharing couples have been previously observed in abnormal pregnancies of unknown etiology. We have determined the HLA-A, B, C and DR antigens of 20 couples with recurrent spontaneous abortions (RSAs), 32 control couples and 100 normal controls. The results showed that in couples with more than two idiopathic repeated abortions, there is no significant increase in the HLA antigen sharing couples. But we were able to observe, in the affected couples, a significant increase in HLA-DR antigen sharing as regards the control couples. We also find a significant increase in the DR5 antigen, in both wives and husbands, in couples with repeated abortions of unknown etiology as previously described for the Dw5 antigen.

Habitual abortion: parental sharing of HLA antigens, absence of maternal blocking antibody, and suppression of maternal lymphocytes

The immunologic responsiveness of eight women who habitually abort has been investigated. All shared an HLA-A or B antigen with their husbands. Sharing of an HLA-DR antigen was found in seven couples, one of which also had a second DR antigen in common. The probability for this high frequency of HLA-DR sharing is negligible (p = 0.0004), as calculated from the antigen frequencies among Europeans. Cells from the woman with two shared DR antigens displayed a minor response to her husband's cells but reacted strongly to control cells, whereas the other women's cells reacted normally to cells from both their husbands and controls in one-way mixed lymphocyte culture (MLC). Only minor cytotoxicity was displayed by women's cells in a direct cell-mediated lympholysis (CML) assay, but they mounted normal cytotoxic responses against both husbands' cells and control cells in an amplified CML assay. The sera from six of the habitually aborting women displayed no blocking activity in one-way MLC, and seven of them had no cytotoxic antibodies. Cells from all habitual aborters were suppressed in two-way MLC by cells from husbands and most controls. We hypothesize that increases in HLA compatibility between mother and fetus and in maternal susceptibility to suppressive influences are in some way linked to a deficiency in the development of antifetal antibody during pregnancy. As a consequence, the fetus may be deprived of the protection by maternal blocking antibody, which may allow maternal cytotoxic reactions to cause abortion.

Easily suppressed lymphocytes and absence of cytotoxic antibody in three women with habitual abortion

This investigation involves 3 women with habitual abortion and 2 women with multiple normal pregnancies. Extensive clinical investigations failed to reveal any cause for the abortions. All husbands were ABO-compatible with their respective wives. The women shared three, two, and zero of five identified HLA-A antigens with their respective husbands. None of the women had any cytotoxic antibody. Lymphocytes from all three women reacted normally in one-way mixed lymphocyte cultures to their husbands' alloantigens. Cell-mediated lympholysis was similar in couples with habitual abortion and in those with repeated normal pregnancies. The women's lymphocytes' proliferation was significantly suppressed by lymphocytes from their husbands and by those from most male controls in two-way mixed lymphocyte culture and double chamber experiments. Two women with 6 and 5 live-born children, respectively, served as controls. Their lymphocytes were not suppressed by lymphocytes from their respective husbands or by those from most male controls in two-way mixed lymphocyte cultures. Their reactions in one-way mixed lymphocyte cultures and in cell-mediated lympholysis, however, did not differ from those of the women with habitual abortion.

Absence of HLA association or linkage for variations in sensitivity to the odor of androstenone

Sensitivity to the odor of 5-androst-16-en-3-one (androstenone), a testosterone metabolite, shows wide variations among unrelated individuals. Analysis of correlations in sensitivity between monozygotic twin pairs, dizygotic twin pairs, and nontwin sib pairs now shows that at least a portion of this variation is genetically determined. However, although data from some mouse studies have suggested a relationship between olfaction and the murine histocompatibility system (H-2), we were unable to demonstrate any role of the human HLA system in explaining the wide individual variations in human sensitivity to androstenone. An additional analysis of HLA antigens among 61 human mating pairs also provided no evidence that HLA phenotypes play a role in human mating preference. These data fail to support a role for the human HLA system in the recognition of an odorant of potential biological significance.

Weight and lymphocyte content of the female rat's thymus following first mating

Eleven groups, each of ten Sprague-Dawley female rats, were sacrificed at 12 to 13 weeks of age; one group of virgins, the others at two-day intervals during the first ten days after either inbred or outbred mating. Observations were made on thymus weight, total white cell count, and thymic white cell density. Compared with the virgin group no significant differences were observed in the thymic weight at any stage after either inbred or outbred mating. In contrast the total white cell counts were significantly greater than the virgin count on the second postcoital day after both inbred and outbred mating. These increased total counts were maintained until the end of the observation period and were associated with significant increases in the thymic white cell densities. These observations suggest that mating and implantation initiate and sustain a mechanism of lymphocyte accumulation in the rat thymus.

Histocompatibility antigens in pregnancy, abortions, infertility, preeclampsia, and trophoblast neoplasms

The genetic makeup of an individual may determine the capacity of the individual to combat successfully cancer and other disease states, eg abnormal pregnancies, abortions, infertility, and preeclampsia. These factors appear to be based upon the individual's immunogenetics, as histocompatibility-restricted T-cell cytotoxicity may be deficient in the observed instances of increased histocompatibility between husband and wife found in trophoblast tumor patients and in other instances of abnormal pregnancies.

Immune response to first mating in the female rat

The iliac and popliteal lymph nodes were removed from 110 Sprague Dawley female rats taken from a closed colony. All were killed at age 12-13 wk in groups of 10 animals; one group of virgin controls, the others at 2-day intervals during the first 10 days of either inbred or allogeneic poregnancy. Every tenth section of the lymph nodes was stained with methyl green pyronin and counts were made of the large pyroninophilic cells in the thymus-dependent area of the cortex for evidence of T cell proliferation and the plasma cells in the medulla for evidence of B cell proliferation. After allogeneic mating significant T cell proliferation was evident in both the iliac and popliteal lymph nodes by the second post-coital day and this proliferative response was sustained until the sixth postcoital day and recurred on the tenth post-coital day. After inbred mating transient T cell proliferation was observed on the fourth post-coital day in the iliac lymph nodes. Significant B cell proliferation occurred in the iliac lymph nodes on the second day of allogeneic pregnancy and on the fourth day of inbred pregnancy, being sustained in both until the end of the observation period. These results suggest that allogeneic mating and possibly semi-allogeneic implantation induce an immune response in the female rat.