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

Correlation analysis between HLA-DQA1*0102/DQB1*0602 genotypes and narcolepsy patients in China

Background and objective

At present, the etiology of narcolepsy is not fully understood, and it is generally believed to be an autoimmune reaction caused by interactions between environmental and genetic factors. Human leukocyte antigen (HLA) class II genes are strongly associated with this gene, especially HLA-DQB1*0602/DQA1*0102. In this study, we mainly analyzed the correlation between different genotypes of HLA-DQB1*0602/DQA1*0102 and clinical manifestations in Chinese patients with narcolepsy.

Experimental method

Narcolepsy patients who were treated at the Department of Neurology, The First Affiliated Hospital of Shandong First Medical University from January 2021 to September 2023 were selected. General information, sleep monitoring data, cerebrospinal fluid (CSF) orexin levels, and human leukocyte antigen gene typing data were collected. The statistical analysis was performed using SPSS 26.0, and the graphs were drawn using GraphPad Prism 9.5.

Main results

A total of 78 patients were included in this study. The DQA1 and DQB1 gene loci were detected in 54 patients, and only the DQB1 gene locus was detected in 24 narcoleptic patients. The most common allele at the HLA-DQB1 locus was *0602 (89.7%), and the most common genotype at this locus was *0602*0301 (19.2%), followed by *0602*0602 (17.9%). The most common phenotype of the HLA-DQA1 locus is *0102 (92.6%), and the most common genotype of this locus is *0102*0102 (27.8%), followed by *0102*0505 (14.8%). There were significant differences (p < 0.05) between HLA-DQB1*0602-positive and HLA-DQB1*0602-negative patients in terms of orexin-A levels, presence or absence of cataplexy, UNS, PSG sleep latency, REM sleep latency, N1 sleep percentage, oxygen depletion index, and average REM latency on the MSLT. The HLA-DQA1*0102-positive and HLA-DQA1*0102-negative patients showed significant differences (p < 0.05) in disease course, presence or absence of sudden onset, PSG REM sleep latency, N1 sleep percentage, and average REM latency on the MSLT. There were significant differences in the average REM latency of the MSLT between HLA-DQB1*0602/DQA1*0102 homozygous and heterozygous patients p < 0.05, and no differences were found in the baseline data, orexin-A levels, scale scores, or other sleep parameters.

Conclusion

Different genotypes of HLA-DQA1*0102/DQB1*0602 are associated with symptoms of cataplexy in Chinese narcoleptic patients. Homozygous individuals have a shorter mean REM latency in the MSLT, greater genetic susceptibility, and relatively more severe sleepiness.

The Influence of Maternal KIR Haplotype on the Reproductive Outcomes after Single Embryo Transfer in IVF Cycles in Patients with Recurrent Pregnancy Loss and Implantation Failure-A Single Center Experience

(1) Background: Recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) have in common a deficient maternal adaptation to the semi-allogeneic fetus, in which killer immunoglobulin-like receptor (KIR) family expressed by natural killer (NK) cells play an important role. The aim of this study was to evaluate the influence of maternal KIR haplotype on the reproductive outcomes after single embryo transfer in IVF cycles in patients with RPL and RIF. (2) Methods: Patients with RIF and RPL who presented at Origyn Fertility Center from Iasi, Romania, were prospectively enrolled between January 2020 and December 2022. Clinical and paraclinical data was examined. Descriptive statistics and a conditional logistic regression model were used to analyze our data. (3) Results: Patients with a KIR AA haplotype had significantly more chances of miscarriage if they underwent an IVF procedure (aOR: 4.15, 95% CI: 1.39-6.50, p = 0.032) compared with those who spontaneously achieved a pregnancy. Moreover, it appeared that the same haplotype increased the chances of obtaining a pregnancy for patients who underwent an IVF procedure (aOR: 2.57, 95% CI: 0.85-6.75, p = 0.023). (4) Conclusions: Determination of KIR haplotype could be beneficial for patients with RPL or RIF in order to offer an individualized management.

Management of recurrent implantation failure: British Fertility Society policy and practice guideline

Recurrent implantation failure (RIF) is defined as the absence of a positive pregnancy test after three consecutive transfers of good quality embryos. There remains significant variation in clinical practice in the management of RIF. This British Fertility Society (BFS) Policy and Practice guideline analyses the evidence for investigations and therapies that are employed in RIF and provides recommendations for clinical practice and for further research. Evidence for investigations of sperm and egg quality, uterine and adnexal factors, immunological factors and thrombophilia, endocrine conditions and genetic factors and for associated therapies have been evaluated. This guideline has been devised to assist reproductive medicine specialists and patients in making shared decisions concerning management of RIF. Finally, suggestions for research towards improving understanding and management of RIF have also been provided.

Genomic Analysis of Spontaneous Abortion in Holstein Heifers and Primiparous Cows

Background: The objectives of this study were to identify loci, positional candidate genes, gene-sets, and pathways associated with spontaneous abortion (SA) in cattle and compare these results with previous human SA studies to determine if cattle are a good SA model for humans. Pregnancy was determined at gestation day 35 for Holstein heifers and cows. Genotypes from 43,984 SNPs of 499 pregnant heifers and 498 pregnant cows that calved at full term (FT) were compared to 62 heifers and 28 cows experiencing SA. A genome-wide association analysis, gene-set enrichment analysis–single nucleotide polymorphism, and ingenuity pathway analysis were used to identify regions, pathways, and master regulators associated with SA in heifers, cows, and a combined population. Results: Twenty-three loci and 21 positional candidate genes were associated (p < 1 × 10⁻⁵) with SA and one of these (KIR3DS1) has been associated with SA in humans. Eight gene-sets (NES > 3.0) were enriched in SA and one was previously reported as enriched in human SA. Four master regulators (p < 0.01) were associated with SA within two populations. Conclusions: One locus associated with SA was validated and 39 positional candidate and leading-edge genes and 2 gene-sets were enriched in SA in cattle and in humans.

KIR, LILRB and their Ligands' Genes as Potential Biomarkers in Recurrent Implantation Failure

Reproductive failure in humans is a very important social and economic problem, because nowadays women decide to conceive later in life and delay motherhood. Unfortunately, with increasing age they have less chance for natural fertilization and maintenance of pregnancy. Many of them need assisted reproductive technology. Approximately 10% of women after in vitro fertilization-embryo transfers experience recurrent implantation failure (RIF). Multiple factors may contribute to RIF, including oocyte and sperm quality, parental chromosomal anomalies, genetic or metabolic abnormalities of the embryo, poor uterine receptivity, immunological disturbances in the implantation site, and some gynecologic pathologies such as endometriosis, uterine fibroids, hydrosalpinx and endometrial polyps. Moreover, the procedure of in vitro fertilization itself could adversely influence the implantation. Nowadays, many studies are focused on the role of natural killer (NK) cells in normal and pathologic pregnancy because NK cells constitute the dominant cell population in the endometrium and they come in close contact with the allogeneic extravillous trophoblast cells in early pregnancy decidua. The majority of these cells are of CD56^bright phenotype. These cells can express killer immunoglobulin-like receptors (KIRs), which, upon recognition of HLA class I molecules (HLA-C and HLA-G) on trophoblasts, may either stimulate or inhibit NK cells to produce soluble factors, and display low cytotoxicity necessary for maintenance of the allogeneic embryo and fetus in the next steps of pregnancy. Moreover, some members of the leukocyte immunoglobulin-like receptor (LILR) family, also named ILT (immunoglobulin-like transcript), are present in the human placenta. LILRB1 (ILT2) was described mainly on stromal cells, while LILRB2 (ILT4), in addition to stromal cells, was also found around vessels in the smooth muscle layer. In this review we focus on the possible role of polymorphism of KIR, LILRB and their ligands (HLA-C, HLA-G) in susceptibility to recurrent implantation failure, which could serve as diagnostic biomarkers of this disease.

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.

Killer cell immunoglobulin-like receptor gene associations with autoimmune and allergic diseases, recurrent spontaneous abortion, and neoplasms

Killer cell immunoglobulin-like receptors (KIRs) are a family of cell surface inhibitory or activating receptors expressed on natural killer cells and some subpopulations of T lymphocytes. KIR genes are clustered in the 19q13.4 region and are characterized by both allelic (high numbers of variants) and haplotypic (different numbers of genes for inhibitory and activating receptors on individual chromosomes) polymorphism. This contributes to diverse susceptibility to diseases and other clinical situations. Associations of KIR genes, as well as of genes for their ligands, with selected diseases such as psoriasis vulgaris and atopic dermatitis, rheumatoid arthritis, recurrent spontaneous abortion, and non-small cell lung cancer are discussed in the context of NK and T cell functions.

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.

Killer immunoglobulin-like receptors (KIRs) and HLA-C allorecognition patterns implicative of dominant activation of natural killer cells contribute to recurrent miscarriages

BACKGROUND

Decidual natural killer (NK) cells play key developmental roles at the feto-maternal interface. Individual differences in NK-cell interactions are dependent on the combinations of variable killer immunoglobulin-like receptor (KIR) and HLA class-I gene products. As different receptor-ligand interactions may result in altered NK-cell-mediated immunity against pathogens, it is proposed that the relationship between these genes may be important in a state such as recurrent miscarriage (RM). We had earlier reported that the predisposition to RM is influenced by the maternal KIR gene content. In the present study, we have attempted to extend our findings in the light of contribution from the paternal antigens on the outcome of pregnancy, since maternal NK cells may potentially encounter non-self-paternal HLA-C alleles on trophoblasts. All HLA-C allotypes fall into two major KIR epitopes--C1 (HLA-C*01/*03/*07/*08/*12/*14/*16) and C2 (HLA-C*02/*04/*05/*06/*15/*17/*18)--on the basis of a dimorphism at position 80 of the α1 domain.

METHODS

PCR-sequence specific primer-based genotyping was used to determine the maternal KIR gene content and HLA-C genotypes down to allele level in couples experiencing RM and controls.

RESULTS

KIR2DL1 with both partners homozygous for HLA C2 was significantly higher in control couples when compared with the patients [P = 0.0004, odds ratio (OR) = 0.28, 95% confidence interval (CI) = 0.13-0.58]. The activating KIR2DS2 with both partners homozygous for HLA C1 was significantly higher in patients when compared with the controls (P = 0.002, OR = 2.83, 95% CI = 1.47-5.40).

CONCLUSIONS

Our results represented the 'top-end' of the activation spectrum of KIR-HLA-C compound genotype for NK cells and this may contribute to the immunological etiology of RM.

HLA sharing among couples appears unrelated to idiopathic recurrent fetal loss in Saudi Arabia

BACKGROUND

Recurrent fetal loss (RFL) is a prevalent problem affecting approximately 1% of all women of childbearing age. Many factors can lead to RFL; however, recent studies have indicated the important role of the maternal immune system in this process. The human leukocyte antigens (HLA), HLA-linked genes and regulatory factors play an important role in fetal loss and in fetal development. The current retrospective study was preformed to examine the HLA alleles shared between couples with RFL in Saudi Arabia, using a large cohort of women (having three or more RFL). Specific HLA alleles that could influence this condition, or the number of miscarriages experienced, were expected to be highlighted in this way.

METHODS

A total of 253 consecutive patients who visited the RFL clinic at the King AbdulAziz Medical City, National Guard Hospital in Riyadh were included in this study. They included 54 consanguineous couples, 132 non-consanguineous couples and another 67 couples shared only their tribal origin. Clinical examinations as well as laboratory investigations were carried out on each patient. Class I HLA, HLA-A, HLA-B and HLA-C, and Class II HLA, HLA-DR and HLA-DQ, were typed for each patient and their partner.

RESULTS

No relationship was seen between sharing of HLA alleles and the number of RFL experienced by the couples, among neither consanguineous nor non-consanguineous couples.

CONCLUSIONS

Although the results of this study suggest that HLA sharing is not an indicative factor in RFL, definitive conclusions on this topic must be based on large case-control studies.