MHC class II compatibility in aborted fetuses and term infants of couples with recurrent spontaneous abortion

Evidence that exposure to progesterone alone is a sufficient stimulus to cause a precipitous rise in the immunomodulatory protein the progesterone induced blocking factor (PIBF)

PURPOSE

To determine if exposure to progesterone alone is sufficient to increase the production of the immunomodulatory protein known as the progesterone induced blocking factor (PIBF). Also to determine what method of progesterone delivery or form of P best stimulates PIBF secretion.

METHODS

Serum samples from patients with infertility and paid volunteers were evaluated for both PIBF and progesterone at various times during the follicular phase and the luteal phase in both natural cycles and cycles involving embryo transfer after endogenous and exogenous progesterone exposure and after various synthetic progestins. PIBF was measured by a non-commercial research ELISA assay. Comparisons were made of serum PIBF before and after exposure to progesterone, 17-hydroxyprogesterone, and oral contraceptives. PIBF was also measured before and after transfer of embryos.

RESULTS

Progesterone alone without exposure to the fetal allogeneic stimulus was able to produce a marked increase in serum PIBF. Neither a synthetic progestin (19-nortestosterone derivative) nor 17-hydroxyprogesterone caused an increase in PIBF. Some PIBF is generally detected even in the follicular phase.

CONCLUSIONS

A previous concept considered that an allogeneic stimulus, e.g., from the fetal semi-allograft, was necessary to induce de novo progesterone receptors in gamma delta T cells, which, in turn, when exposed to a high concentration of progesterone, would secrete high levels of PIBF. These data show that exposure to an allogeneic stimulus is not needed to cause a marked rise in PIBF, merely progesterone alone is sufficient.

HLA associations and HLA sharing in recurrent miscarriage: A systematic review and meta-analysis

PROBLEM

The aim of this meta-analysis was to evaluate whether specific maternal HLA alleles and HLA sharing of couples are associated with the occurrence of recurrent miscarriage (RM).

METHOD OF STUDY

A systematic literature search was performed for studies that evaluated the association between HLA alleles, HLA sharing and RM. RM was defined as three or more consecutive unexplained miscarriages and a control group was included of women with at least one live birth and no miscarriages in their history. Meta-analyses were performed and the pooled odds ratio (OR) was calculated.

RESULTS

We included 41 studies. Selection bias was present in 40 studies and information bias in all studies. Meta-analyses showed an increased risk of RM in mothers carrying a HLA-DRB1*4 (OR 1.41, 95% CI 1.05-1.90), HLA-DRB1*15 (OR 1.57, 95% CI 1.15-2.14), or a HLA-E*01:01 allele (OR 1.47, 95% CI 0.20-1.81), and a decreased risk with HLA-DRB1*13 (OR 0.63, 95% CI 0.45-0.89) or HLA-DRB1*14 (OR 0.54, 95% CI 0.31-0.94). Pooling results for HLA sharing showed that HLA-B sharing (OR 1.39, 95% CI 1.11-1.75) and HLA-DR sharing (OR 1.57, 95% CI 1.10-1.25) were both associated with the occurrence of RM.

CONCLUSION

Although the present systematic review and meta-analysis demonstrates that specific HLA alleles and HLA sharing are associated with RM, a high degree of bias was present and therefore observed results should be interpreted carefully.

Maternal HLA-C2 and 14 bp insertion in HLA-G is associated with recurrent implantation failure after in vitro fertilization treatment

The major rate-limiting step in in vitro fertilization (IVF) success appears to be the implantation of the semi-allogeneic embryo into the maternal endometrium. To determine possible risk factors of recurrent failure of embryos to implant, we investigated immunogenetic determinants as level of human leukocyte antigen (HLA) histocompatibility, frequency of killer-cell immunoglobulin-like receptors (KIR) and HLA-C alleles and HLA-G polymorphism. We DNA typed women with recurrent implantation failure (RIF) and their partners for classical HLA Class I, HLA Class II, HLA-G and KIR alleles and compared these results with couples with successful embryo implantation after their first IVF and normal fertile couples. No association was found between RIF and the degree of histocompatibility between partners or sharing of a specific antigen. Also, no significant difference in KIR haplotype or combination of HLA-C group and KIR was observed. We did find a higher frequency of HLA-C2 and a higher frequency of 14 base pair (bp) insertion in HLA-G in women with RIF. Therefore we conclude that the degree of histocompatibility between partners is not a determining factor for the occurrence of RIF. However, presence of the HLA-C2 allotype and the HLA-G allele with a 14 bp insertion is a significant risk factor.

Large-scale MHC class II genotyping of a wild lemur population by next generation sequencing

The critical role of major histocompatibility complex (MHC) genes in disease resistance, along with their putative function in sexual selection, reproduction and chemical ecology, make them an important genetic system in evolutionary ecology. Studying selective pressures acting on MHC genes in the wild nevertheless requires population-wide genotyping, which has long been challenging because of their extensive polymorphism. Here, we report on large-scale genotyping of the MHC class II loci of the grey mouse lemur (Microcebus murinus) from a wild population in western Madagascar. The second exons from MHC-DRB and -DQB of 772 and 672 individuals were sequenced, respectively, using a 454 sequencing platform, generating more than 800,000 reads. Sequence analysis, through a stepwise variant validation procedure, allowed reliable typing of more than 600 individuals. The quality of our genotyping was evaluated through three independent methods, namely genotyping the same individuals by both cloning and 454 sequencing, running duplicates, and comparing parent-offspring dyads; each displaying very high accuracy. A total of 61 (including 20 new) and 60 (including 53 new) alleles were detected at DRB and DQB genes, respectively. Both loci were non-duplicated, in tight linkage disequilibrium and in Hardy-Weinberg equilibrium, despite the fact that sequence analysis revealed clear evidence of historical selection. Our results highlight the potential of 454 sequencing technology in attempts to investigate patterns of selection shaping MHC variation in contemporary populations. The power of this approach will nevertheless be conditional upon strict quality control of the genotyping data.

Molecules and mating: positive selection and reproductive behaviour in primates

Sexual reproduction is generally thought to be more costly than asexual reproduction. However, it does have the advantage of accelerating rates of adaptation through processes such as recombination and positive selection. Comparative studies of the human and nonhuman primate genomes have demonstrated that positive selection has played an important role in the evolutionary history of humans and other primates. To date, many dozens of genes, thought to be affected by positive selection, have been identified. In this chapter, we will focus on genes that are associated with mating behaviours and reproductive processes, concentrating on genes that are most likely to enhance reproductive success and that also show evidence of positive selection. The genes encode phenotypic features that potentially influence mate choice decisions or impact the evolution and function of genes involved in the perception and regulation of, and the response to, phenotypic signals. We will also consider genes that influence precopulatory behavioural traits in humans and nonhuman primates, such as social bonding and aggression. The evolution of post-copulatory strategies such as sperm competition and selective abortion may also evolve in the presence of intense competition and these adaptations will also be considered. Although behaviour may not be solely determined by genes, the evidence suggests that the genes discussed in this chapter have some influence on human and nonhuman primate behaviour and that positive selection on these genes results in some degree of population differentiation and diversity.

Gestational dermatosis shortly after implantation associated with parental class II HLA compatibility and maternal immune activation: preliminary report of a prospective case series

BACKGROUND

Pregnancy represents a semi-allograft, subject to similar immune responses as allogeneic organ transplants. Tolerance of pregnancy appears best with maximal class II HLA heterogeneity between mother and father, while compatibilities are associated with increased pregnancy loss and maternal autoimmunity. Tolerance abnormalities often involve skin reactions. Abnormalities in tolerance of the fetal graft may do the same.

OBJECTIVE

To define the characteristics of a newly described dermatosis in very early pregnancy.

METHODS

Prospective case series of 7 couples/12 clinical episodes.

RESULTS

The dermatosis was observed in 7 out of 285 women undergoing in vitro fertilization (IVF; 2.5%; 95% CI 0.66-4.26%) and in 12 out of 277 total IVF cycles reaching embryo transfer (4.3%; 95% CI 1.93-6.73%). Prior to IVF all women reported autoimmune clinically significant allergies. All but 1 couple demonstrated class II HLA compatibility. Two of 4 pregnancies miscarried. All rashes erupted within days from embryo implantation.

CONCLUSIONS

The 'implantation rash' reported here is uncommon but not rare. It may be the consequence of abnormal maternal immune responses to embryo implantation in women with prior immune activation, associated with class II HLA compatibility between parents. Further prospective studies are required to better define this condition.

Novel alleles of HLA-DQ and -DR loci show association with recurrent miscarriages among South Indian women

BACKGROUND In this study, recurrent miscarriages (RMs) are defined as loss of two or more clinically detectable pregnancies before 20 weeks of gestation. HLA has been thought to play a role in RM. However, the results of earlier studies on the role of different human leucocyte antigen (HLA) genes were conflicting and inconclusive. In the present study, we investigate HLA genes (HLA-DRA, HLA-DRB1, HLA-DQA1 and HLA-DQB1) in RM couples with unknown etiology and normal couples. METHODS Blood samples from 143 RM couples and 150 control couples were analyzed, firstly to validate previously reported association studies and secondly to explore whether any novel alleles or haplotypes specific to Indian populations can be observed to be associated with RM. HLA typing was carried out by DNA sequencing. RESULTS Results suggest an association of the DQB1*03:03:02 allele with RM (odd ratio = 2.66; p(c) = 0.02; confidence interval = 1.47-4.84). Haplotypes of the DQA1 and DQB1 risk alleles also showed a significant association with RM, albeit not after Bonferroni correction for multiple comparisons. CONCLUSIONS HLA-DQB1 appears to have a strong involvement in the manifestation of RM in this population from South India. The current genetic analysis of RM and control couples not only highlights the genes exhibiting a strong etiological role but also reflects the protective nature of some HLA genes against RM. Nevertheless, most of these alleles/haplotypes were not those that are implicated in RM in other ethnic backgrounds, and hence require further validation in other populations of India, from different ethnic and/or geographic backgrounds.

Homozygosity at a class II MHC locus depresses female reproductive ability in European brown hares

The link between adaptive genetic variation, individual fitness and wildlife population dynamics is fundamental to the study of ecology and evolutionary biology. In this study, a Bayesian modelling approach was employed to examine whether individual variability at two major histocompatibility complex (MHC) class II loci (DQA and DRB) and eight neutral microsatellite loci explained variation in female reproductive success for wild populations of European brown hare (Lepus europaeus). We examined two aspects of reproduction: the ability to reproduce (sterility) and the number of offspring produced (fecundity). Samples were collected from eastern Austria, experiencing a sub-continental climatic regime, and from Belgium with a more Atlantic-influenced climate. As expected, reproductive success (both sterility and fecundity) was significantly influenced by age regardless of sampling locality. For Belgium, there was also a significant effect of DQA heterozygosity in determining whether females were able to reproduce (95% highest posterior density interval of the regression parameter [-3.64, -0.52]), but no corresponding effect was found for Austria. In neither region was reproduction significantly associated with heterozygosity at the DRB locus. DQA heterozygotes from both regions also showed a clear tendency, but not significantly so, to produce a larger number of offspring. Predictive simulations showed that, in Belgium, sub-populations of homozygotes will have higher rates of sterile individuals and lower average offspring numbers than heterozygotes. No similar effect is predicted for Austria. The mechanism for the spatial MHC effect is likely to be connected to mate choice for increased heterozygosity or to the linkage of certain MHC alleles with lethal recessives at other loci.

HLA-DQA1*0505 sharing and killer immunoglobulin-like receptors in sub fertile couples: report from the 15th International Histocompatibility Workshop

This aim of the study was to investigate whether human leukocyte antigen (HLA)-DQA1*0505 sharing or the maternal killer immunoglobulin-like receptor (KIR) repertoire is associated with recurrent spontaneous abortion (RSA) or repeated implantation failure (RIF). The study included 224 couples with RSA, 61 couples with RIF, 182 fertile couples, and 10 couples with successful in vitro fertilization and embryo transfer (IVF)/ET at first cycle. HLA-DQA1*0505 typing using polymerase chain reaction-sequence-specific oligonucleotide (PCR-SSO) was performed in 185 RSA (117 with alloimmune abnormalities and 68 of autoimmune etiology), 61 RIF and 182 control couples, and KIR genotyping using polymerase chain reaction-sequence-specific primer (PCR-SSP) in 167 RSA and 55 RIF cases as well as 46 RSA and 10 IVF controls. No differences in DQA1*0505 sharing were found between patients and controls. In RSA and RIF women, the ratio of inhibitory to activating KIRs was slightly lower (1.53 and 1.85 vs 2.03 in controls). The analysis of maternal inhKIR and fetal HLA-C molecule pairs showed that the 'less inhibiting' combination KIR2DL3-C1 was found in higher percentage in subfertile (mainly RIF) than in fertile couples. In contrast, the percentage of cases possessing the 'strong inhibiting' combination KIR2DL1-C2 was lower in the RSA and RIF groups in comparison with that in the control groups (17.36% vs 23.91 and 16.36% vs 40%, respectively). In women with >or= 6 implantation failures, the KIR2DL1-C2 combination was not found in any of them (P = 0.0014), and the KIR2DL3-C1 combination was not found in the control IVF group. The results oppose the suggestion that increased HLA-DQA1*0505 sharing predispose to RSA or RIF. The KIR2DL3-C1 combination (or lack of the KIR2DL1-C2 one) is associated with implantation failure.

Giant panda genomic data provide insight into the birth-and-death process of mammalian major histocompatibility complex class II genes

To gain an understanding of the genomic structure and evolutionary history of the giant panda major histocompatibility complex (MHC) genes, we determined a 636,503-bp nucleotide sequence spanning the MHC class II region. Analysis revealed that the MHC class II region from this rare species contained 26 loci (17 predicted to be expressed), of which 10 are classical class II genes (1 DRA, 2 DRB, 2 DQA, 3 DQB, 1 DYB, 1 DPA, and 2 DPB) and 4 are non-classical class II genes (1 DOA, 1 DOB, 1 DMA, and 1 DMB). The presence of DYB, a gene specific to ruminants, prompted a comparison of the giant panda class II sequence with those of humans, cats, dogs, cattle, pigs, and mice. The results indicated that birth and death events within the DQ and DRB-DY regions led to major lineage differences, with absence of these regions in the cat and in humans and mice respectively. The phylogenetic trees constructed using all expressed alpha and beta genes from marsupials and placental mammals showed that: (1) because marsupials carry loci corresponding to DR, DP, DO and DM genes, those subregions most likely developed before the divergence of marsupials and placental mammals, approximately 150 million years ago (MYA); (2) conversely, the DQ and DY regions must have evolved later, but before the radiation of placental mammals (100 MYA). As a result, the typical genomic structure of MHC class II genes for the giant panda is similar to that of the other placental mammals and corresponds to BTNL2∼DR1∼DQ∼DR2∼DY∼DO_box∼DP∼COL11A2. Over the past 100 million years, there has been birth and death of mammalian DR, DQ, DY, and DP genes, an evolutionary process that has brought about the current species-specific genomic structure of the MHC class II region. Furthermore, facing certain similar pathogens, mammals have adopted intra-subregion (DR and DQ) and inter-subregion (between DQ and DP) convergent evolutionary strategies for their alpha and beta genes, respectively.

Giant panda BAC library construction and assembly of a 650-kb contig spanning major histocompatibility complex class II region

Background

Giant panda is rare and endangered species endemic to China. The low rates of reproductive success and infectious disease resistance have severely hampered the development of captive and wild populations of the giant panda. The major histocompatibility complex (MHC) plays important roles in immune response and reproductive system such as mate choice and mother-fetus bio-compatibility. It is thus essential to understand genetic details of the giant panda MHC. Construction of a bacterial artificial chromosome (BAC) library will provide a new tool for panda genome physical mapping and thus facilitate understanding of panda MHC genes.

Results

A giant panda BAC library consisting of 205,800 clones has been constructed. The average insert size was calculated to be 97 kb based on the examination of 174 randomly selected clones, indicating that the giant panda library contained 6.8-fold genome equivalents. Screening of the library with 16 giant panda PCR primer pairs revealed 6.4 positive clones per locus, in good agreement with an expected 6.8-fold genomic coverage of the library. Based on this BAC library, we constructed a contig map of the giant panda MHC class II region from BTNL2 to DAXX spanning about 650 kb by a three-step method: (1) PCR-based screening of the BAC library with primers from homologous MHC class II gene loci, end sequences and BAC clone shotgun sequences, (2) DNA sequencing validation of positive clones, and (3) restriction digest fingerprinting verification of inter-clone overlapping.

Conclusion

The identifications of genes and genomic regions of interest are greatly favored by the availability of this giant panda BAC library. The giant panda BAC library thus provides a useful platform for physical mapping, genome sequencing or complex analysis of targeted genomic regions. The 650 kb sequence-ready BAC contig map of the giant panda MHC class II region from BTNL2 to DAXX, verified by the three-step method, offers a powerful tool for further studies on the giant panda MHC class II genes.

14th International HLA and Immunogenetics Workshop: Report from the reproductive immunology component

The aim of the study was to investigate whether human leukocyte antigen (HLA) allele sharing between partners or the maternal killer immunoglobulin-like receptor (KIR) repertoire is associated with recurrent spontaneous abortion (RSA) and repeated implantation failure after in vitro fertilization (IVF)/embryo transfer. From a total population of 158 RSA couples, 40 couples with repeated implantation failures (IVF) and 81 control couples, reported by five different laboratories, analysis was performed for (a) HLA sharing in 50 RSA, 31 IVF and 31 control couples, (b) DQA1*0505 sharing/homozygosity among partners in 108 RSA, 40 IVF and 36 control couples, and (c) the women's KIR repertoire in 46 RSA, 26 IVF and 36 control wives. RSA couples were divided into alloimmune aborter (RSAallo) and autoimmune aborter (RSAauto). The results oppose to the suggestion that increased HLA sharing per se or a limited maternal KIR repertoire predisposes to RSA or IVF failure. However, the observation of a slightly higher percentage of DQA1*0505 sharing in the RSAauto and the IVF group needs further investigation. The ratio of inhibitory to activating KIR (actKIR) was slightly lower in RSAallo and IVF women (1.9 vs 2.6 in controls), while in a high percentage of these women, the standard receptors of the KIR A haplotype were combined with actKIR/s of the haplotype B (66.6% and 45.4% vs 20% and 15.3% in RSAauto and control groups). This may suggest a possible involvement of actKIRs in embryo implantation and the maintenance of pregnancy and also requires further investigation.

Molecular genetic studies on the compatibility of HLA class II alleles in patients with unexplained recurrent miscarriage in the Japanese population

It is hypothesized that patients having unexplained recurrent miscarriage lack an appropriate immune reaction against their partner's antigens, which means possible compatibility of HLA antigens between the patient couples. The conclusion, however, has not yet been achieved, so the purpose was to determine whether significant compatibility of HLA class II exists between the couples. The HLA-DRB1 and -DQB1 genotypes were determined using PCR-RFLP method in 91 patient couples and in 72 normal couples. The number of patient couples with zero-allele mismatch was not significantly different compared with that of control couples regarding HLA-DRB1 genotype and phenotype, as well as regarding HLA-DQB1 genotype and phenotype. While the number of patient couples with zero- and one-allele mismatch was significantly higher compared with that in control as to HLA-DR and -DQ phenotype (P=0.029 by Chi-square test). In conclusion, it is suggested that the compatibility of HLA class II antigens between couples might be involved in the genesis of unexplained recurrent miscarriage.

Association of human leucocyte antigen sharing with recurrent spontaneous abortions

An estimated 15% of clinically recognized pregnancies abort spontaneously. Recurrent spontaneous abortion (RSA) is defined as three or more consecutive miscarriages conceived with the same partner in the absence of uterine, genetic or autoimmune abnormalities. Evidence points to human leucocyte antigens (HLA) as playing a role in the successful development of the foetus. In particular, HLA compatibility is more prevalent in couples experiencing reproductive failure, especially RSA couples, compared to fertile couples. According to the immunological hypothesis, an adequate immune response is necessary for proper implantation of the embryo; conversely, a depressed response of maternal lymphocytes to the stimulation by paternal antigens because of HLA sharing can result in disorders, such as RSA. The genetic hypothesis implicates homozygosity for recessive lethal alleles in linkage disequilibrium with specific HLA haplotypes. The specificity of HLA alleles or haplotypes responsible for or linked to other RSA susceptibility genes remains unclear. In this study, we identified 40 observational studies (32 case-control, five cohort, one cross-sectional, one case series and one basic science) that examined the associations between HLA and RSA, focusing on HLA allele couple and maternal-foetal sharing, and the special role of HLA-G. We sought to identify consistent findings among studies examining similar questions. Evidence remains divided concerning the role of HLA allele couple sharing. Of major concern is the focus of many studies on couple sharing as a proxy measure of maternal-foetal sharing. Therefore, adequately powered studies are needed, which employ standard case definitions and reproducible methodologies to directly assess the role of maternal-foetal HLA sharing on the risk of RSA.

The Potential Role of HLA-G Polymorphism in Maternal Tolerance to the Developing Fetus

The mechanism by which the developing fetus survives the maternal immunity has eluded investigators and remains a central paradox in the field of stem cell research. If the mechanism can be defined, allogenic stem cells may find increased utility after transplantation. While several theories have been advanced, the differential expression of HLA antigens on trophoblasts has been the focus of many studies. Interestingly, an inverse relationship between HLA-G (nonclassical class I molecules) and class I MHC gene expression exists early in pregnancy. HLA-G transcripts are present in quite significant amounts in first-trimester placental tissue, particularly in the extravillous membranes, while the opposite occurs at term. This kind of expression is consistent with the theory that HLA-G might play a role in fetal protection. This could be consequent to either nonimmune (structural) or immune functions at the maternal-fetal interface. Current evidence suggest an immune function wherein HLA-G protects fetal cells from maternal uterine natural killer (NK) cells, which are found in large numbers within cells invading the trophoblasts. This effect has been attributed to maternal NK receptor alterations as well as inhibition of maternal NK cell traffic across the placenta. The recent identification of HLA-G polymorphism brings into play the potential role of these isoforms in fetal protection. Polymorphism may be associated with differential function or may effect linkage disequilibria with other HLA variants, providing fetal protection.

Linking olfaction with nausea and vomiting of pregnancy, recurrent abortion, hyperemesis gravidarum, and migraine headache

OBJECTIVE

The experience of women was sought about nausea and vomiting, its relation to olfaction, its occurrence among pregnant women with anosmia, and the potential association of hyperemesis gravidarum and migraine headache.

METHODS

We performed a community-based study with a physician/patient-directed questionnaire, and a retrospective analysis of hospital records.

RESULTS

Nearly all women (n = 163 parous women) experience nausea (98%) and vomiting (97%). The highest frequency causes of nausea and vomiting were "food poisoning" (65%), "flu" (58%), pregnancy (54%), and offensive odors (52%); vomiting occurred as frequently as nausea for the first 2 causes, and one half as often for the latter causes. Most women reported that the pain experienced during vomiting exceeded that of parturition. Among 9 women with hypogonadotropic anosmia with advanced reproductive technology-induced pregnancies, 2 experienced nausea and vomiting, one from "food poisoning." Among 37 women with migraine headache, 10 (27%) had experienced hyperemesis gravidarum, and among 16 who experienced hyperemesis gravidarum, 5 (37%) had migraine headaches.

CONCLUSIONS

The frequency of nausea and vomiting, caused most often by nonpregnancy-related triggers, is high among women. In a small sample of women with congenital anosmia, nausea and vomiting of pregnancy occurred in only 1 pregnancy, suggesting that olfaction is a highly selected trigger for nausea and vomiting of pregnancy. The shared nausea and vomiting experience of hyperemesis gravidarum and migraine headache among women suggests a common mechanism, possibly based on allelic variations within the DRD2 (dopaminergic receptor) gene. Because olfactory receptors, odor types, and MHC antigens are closely integrated, and because olfactory stimuli often incite episodes of pregnancy, nausea, and vomiting, hyperemesis gravidarum, and migraine headache, these genes and their products invite further scrutiny. The pregnancy-conserving effect of PNV and the MHC antigen overlap in couples with recurrent abortion are important clues possibly relating olfaction, MHC antigens, and reproductive success or failure.

A model for potential tumor immunotherapy based on knowledge of immune mechanisms responsible for spontaneous abortion

Attempts to treat various cancers by immunotherapy have been tried for about 50 years. Most studies have focused on improving cytotoxic T lymphocyte (CTL) responses against various tumors. Immunotherapy has been both active and passive, and results have been modest at best. Spontaneous abortion (SAB) of pregnancies could in some ways resemble remission of a tumor. Both tumors and conceptusses are faced with a similar problem -- how to grow in a host in a vascular rich area, and yet escape immune surveillance despite both entities being an allogenic stimulus. In general, the fetus is far more immunogenic than a spontaneous tumor, and yet abortuses seem to avoid CTL responses but are sometimes invaded by natural killer (NK) cells. There are data suggesting that SAB will occur if there is inhibition of production of an immunosuppressive protein called progesterone-induced blocking factor (PIBF). This protein inhibits NK cell cytolysis and influences TH2 cytokine dominance over TH1. If some tumors avoid NK cell destruction through a PIBF mechanism, perhaps an active rejection of these tumors could be achieved by inhibiting PIBF production by treating with a progesterone receptor antagonist. Passive immunization could also be considered by conjugative radionuclide or toxic chemical to a PIBF antibody which may be tumor specific since PIBF is not produced in normal tissue. The first step should be to see if PIBF can be detected in the peripheral circulation in patients with certain tumors.

Evidence for major histocompatibility complex-mediated effects on spermatogenesis in humans

Studies in fertile and infertile populations suggest an influence of genes of the major histocompatibility complex (MHC) on reproduction, although it remains unresolved if MHC-mediated effects on fertility are based on direct immunological or non-immunological effects of human leukocyte antigen (HLA) genes or rather on defects in MHC-associated non-HLA genes which affect gamete quality and embryonic development. We analysed allele frequencies for HLA class II loci DQA1, DQB1 and DRB1 and HLA class II haplotype frequencies in couples with tubal and andrological infertility who were treated with assisted reproductive techniques. Males with severe andrological infertility had significantly different allele frequencies for all three HLA loci when compared to males with normozoospermia, whereas no difference was found in the females. Differences in allele frequencies were stronger when only males whose partners achieved pregnancies after assisted reproduction treatment were compared. In those subgroups, we could also observe significant differences in three locus HLA class II haplotype frequencies. In summary, patients with male factor infertility differ in their HLA class II allele constitution from males with normozoospermia, which suggests that genes identical to or located in close vicinity to HLA class II genes may influence spermatogenesis and male gamete function.

Possible susceptibility of the HLA-DPB1*0402 and HLA-DPB1*04 alleles to unexplained recurrent abortion: analysis by means of polymerase chain reaction-restricted fragment length polymorphism method

PROBLEM

To clarify whether HLA-DP antigens are associated with patient population of unexplained recurrent abortion.

METHOD OF STUDY

The frequency of HLA-DPB1 alleles in patients with unexplained recurrent abortion, and the compatibility of HLA-DPB1 alleles between patient couples, were studied using a polymerase chain reaction (PCR)-restricted fragment length polymorphism (RFLP) method. Thirty patients who had a history of unexplained primary recurrent abortion, and their husbands, were typed for HLA-DPB1 genotype. Two hundred and ninety-nine base pair fragments from the second exon of HLA-DPB1 genes were selectively amplified using the PCR-primers. After amplification, the DNAs were digested with restriction endonucleases, and subjected to electrophoresis in a 12% polyacrilamide gel to determine HLA-DPB1 genotype.

RESULTS

The frequency of HLA-DPB1*0402 and DPB1*04 alleles in the patient group (n = 30) was significantly increased, as compared to that in the normal fertile women (n = 30). The frequency of HLA-DPB1*04 allele in the patient group was significantly increased, as compared to that in the general population (n = 112). No significant compatibility of HLA-DPB1 alleles could be observed between patient couples and normal fertile couples.

CONCLUSION

These findings suggest a possible new class II association with patient population of unexplained recurrent abortion.

Analyses of HLA-DQ alleles in recurrent spontaneous abortion (RSA) couples

PROBLEM

The influence of HLA sharing on pregnancy outcome is controversial. In renal transplantation, HLA-DQB1 donor-recipient mismatches have been shown beneficial for long-term transplant success. Since pregnancy is defined as Nature's allograft, we investigated the relevance of HLA-DQ mismatching in normal reproducing couples compared to couples experiencing RSA.

METHOD

Unexplained RSA couples referred to our laboratory for immunological testing were classified by immunological findings and obstetrical history. Primary RSA couples shared > or = 2 HLA-A, B, or DR antigens, had no cytotoxic anti-paternal antibodies, and no gestation beyond 20 weeks. Secondary RSA couples had cytotoxic anti-paternal antibodies and RSA after a live birth. HLA-DQA1 and DQB1 alleles were identified by PCR-SSP.

RESULTS

No differences in DQA1 and DQB1 mismatch were observed among RSA patients and controls. DQA1-DQB1 haplotype mismatches were not different among the three groups of couples.

CONCLUSIONS

In contrast to renal transplant, HLA-DQ incompatibility did not differ among RSA couples compared with successful reproducing couples.

Human leukocyte antigen DQ alpha sharing is not increased in couples with recurrent miscarriage

PROBLEM

The results regarding human leukocyte antigen (HLA) DQ alpha allele sharing in recurrent miscarriage couples are conflicting. The purpose of this study was to determine the frequency of HLA DQ alpha allele sharing in our unexplained recurrent spontaneous abortion (RSA) patients using modern DNA analytical techniques.

METHODS

DNA was extracted from whole blood samples of 1) 51 couples with at least three miscarriages, and 2) 43 fertile couples (with at least seven children and no known history of recurrent miscarriage). The polymerase chain reaction (PCR) was used to amplify the second exon of the HLA DQ alpha locus on chromosome 6. Genotypes were identified by allele specific hybridization with 12 sequence-specific oligonucleotide probes.

RESULTS

47% of recurrent miscarriage couples and 35% of fertile couples shared no alleles. 47% of recurrent miscarriage couples compared to 58% of fertile couples shared one allele, and 6% of recurrent miscarriage couples and 7% of fertile couples shared two alleles.

CONCLUSIONS

Reproductive partners with unexplained recurrent pregnancy loss have no increased frequency of HLA DQ alpha allele sharing. It is unlikely that HLA DQ alpha genotyping will be helpful in the management of patients with RSA.

Current topic: HLA and reproduction: lessons from studies in the Hutterites

The paradoxical observation that maternal-fetal incompatibility with respect to human leucocyte antigen (HLA) genes was not associated with spontaneous abortion, stillbirths or developmental abnormalities led to the hypothesis that fetuses with paternally-derived HLA that differ from maternal HLA may enjoy a selective advantage during pregnancy. If true, then couples who share HLA should experience poorer reproductive outcome than couples not sharing HLA. Numerous, retrospective studies of parental HLA sharing and fetal wastage in humans have yielded conflicting results and discrepancies are difficult to reconcile because of methodological differences among studies and potential heterogeneity among subjects. To explore the hypothesis that maternal-fetal HLA compatibility is deleterious in human pregnancy, we initiated prospective and population-based studies in the Hutterites, a religious isolate that lives communally and proscribes contraception. Our data suggest that HLA-DR-linked genes may affect fertilization or implantation and HLA-B-linked genes may contribute toward recognized fetal loss. Discrepant results among retrospective studies of outbred couples may be due to the fact that more than one HLA region influences reproductive outcome and that the genes influencing fertility may not be HLA genes per se, but loci in linkage disequilibrium with HLA-B and HLA-DR.

HLA-DQA1 and HLA-DQB1 haplotypes in aborted fetuses and couples with recurrent spontaneous abortion

HLA haplotypes may be associated with spontaneous abortion through a variety of mechanisms, including maternal hyporesponsiveness to fetal alloantigens, maternal autoimmunity, and HLA-linked t-locus homologues. HLA-DQA1 and HLA-DQB1 haplotypes were determined in 37 couples with a history of recurrent spontaneous abortion (RSAB), 40 of their abortuses, and 20 fertile control couples. The distribution of haplotype frequencies did not differ between control subjects and RSAB wives, RSAB husbands, or abortuses. The frequency of the HLA-DR5-linked haplotype, DQA1*501/DQB1*301, which was considered a marker for immune hyporesponsiveness, did not differ between RSAB wives and control subjects (P = 0.353). The frequency of the autoimmune-associated HLA-DR3-linked haplotype, DQA1*0501/DQB1*0201, did not differ significantly between RSAB wives and control subjects (P = 0.103). The frequency of the DQA1*0201/DQB1*0201 haplotype in RSAB husbands was greater than the 95th percentile confidence limit of the frequency of this haplotype in control subjects. Among seven RSAB husbands who were heterozygous for this haplotype and did not share a DQA1*0201 allele with his wife, the haplotype was transmitted to 6 of 7 abortuses (3.5 expected). Although the small size of this sample precludes drawing conclusions regarding HLA transmission biases in RSAB couples, these data have generated a specific hypothesis regarding the DQA1*0201/DQB1*0201 haplotype that can be investigated in future studies.