DRB1 Alleles Research Articles

HLA Genetic Variants in COVID-19 Susceptibility: Assessing Diversity in Indian and Global Populations

Background: The rapid spread of the SARS-CoV-2 virus has had a global impact on various ethnic groups. In order to assess the genetic predisposition of the Indian population towards COVID-19, a comparative analysis was conducted using the Human Leukocyte Antigen (HLA) to investigate the frequencies of polymorphisms directly or potentially associated with COVID-19 susceptibility, severity, immune response, and fatal outcomes in comparison to other major populations. Objectives: The objective of this study is to evaluate the genetic predisposition of the Indian population to COVID-19 by analyzing the frequencies and associations of Human Leukocyte Antigen (HLA) polymorphisms. In addition, by delineating the role of specific HLA variants in the Indian context, the study seeks to enhance our understanding of genetic factors influencing COVID-19 impact and contribute to personalized approaches for disease management and prevention across diverse ethnic groups. Methods: We collected allelic information for DRB1 gene from 653 populations globally, as documented in The Allele Frequency Net Database (AFND). Data on COVID-19 susceptibility, severity, mortality, and protective factors were obtained from a previous global study. This study aimed to compare the specific frequencies of HLA-DRB1* in different ethnic groups, including other Indian populations with COVID-19-associated alleles and protective factors. Results: HLA-DRB1*01 was identified as a significant determinant of COVID-19 susceptibility among patients in 28 states of Mexico, whereas DRB1*08 in Saudi Arabian populations, DRB1*09:01 in Japanese populations, and DRB1*15:01 in Italian populations also showed this association. Likewise, DRB1*04 in the Iranian population played a role in disease severity, and DRB1*08 in the Italian population was associated with mortality in COVID-19 patients. In addition, alleles DRB1*01:01 and DRB1*04:01 were found to exhibit a protective role in Northeast England, whereas DRB1*04 demonstrated protective effects in Saudi Arabian populations. Conclusion: The involvement of HLA in COVID-19 requires further investigation, and epidemiological studies should focus on HLA profiles as determinants of the host immune system. Prolonged homozygosity in particular genomic regions could potentially increase susceptibility to COVID-19 infection. Therefore, prudent management strategies are recommended for this pandemic in isolated communities in India and worldwide.

Frequency and relationship of HLA allele in Turkish patients with Fanconi anemia

Purpose: Fanconi anemia (FA) is a childhood disorder inherited in an autosomal recessive manner. It is characterized by bone marrow failure, a range of congenital physical abnormalities, increased susceptibility to cancer, chromosomal instability, and heightened sensitivity to cross-linking agents. The aim of this study was to determine the role of the HLA Class I and Class II alleles in genetic susceptibility to Fanconi anemia in Turkish patients. Materials and Methods: In this study, we retrospectively evaluated the HLA-A, -B, and -DRB1 allele frequencies of patients with Fanconi anemia who underwent hematopoietic stem cell transplantation between 2010 and 2021. HLA-A, -B, -DR of all patients and healthy Turkish individuals were genotyped. Results: The study included 86 patients with Fanconi anemia and 300 healthy controls. The most common antigens in patients with Fanconi were HLA-A*02, HLA-B*35 and DRB1*11. Moreover, in the patient group, the HLA-A*23 allele was significantly lower than the control group. When we evaluated the patient group according to gender the HLA-A*01 allele was significantly higher in the female patient group. Conclusion: Our study provides valuable insights into the genetic susceptibility of Turkish patients with Fanconi anemia, focusing on the role of HLA Class I and Class II alleles. HLA-B*14 may be a risk factor and HLA-A*23 may be protective for Fanconi anemia. These results contribute to our understanding of the complex genetic factors underlying Fanconi anemia and may have implications for improved diagnosis, prognosis, and potential therapeutic interventions for affected individuals.

Prevalence of Human Leukocyte Antigen Alleles Polymorphism in North Indian Population

Background Human leukocyte antigens (HLA) are highly polymorphic glycoproteins required for immune response and recognizing self or non-self. Knowing the HLA diversity in a population may be helpful in the selection of organ allocation for transplantation. We aimed to retrospectively analyze the prevalence of HLA, A, B, C, DRB1, and DQA1 alleles frequency in the north Indian population. Materials and Methods HLA antigen allele data were retrospectively analyzed from a transplant cohort of 2259 subjects. HLA-A, B, and DRB1 frequency were determined in 2259, HLA-C in 759 and DQA1 in 751 subjects. Results The most abundant HLA-A antigen alleles were HLA-A*01(25.41%), HLA-A*02 (24.83%), HLA-A*11 (17.53%), HLA-A*24 (10.27%), HLA-A*03 (9.07%). HLA-B antigen alleles were HLA-B*35 (20.54%), HLA-B*15 (15.36%), HLA-B*40 (13.59%), HLA-B*07 (10.14%), HLA-B*44 (7.79). HLA-C antigen alleles were HLA-C*07 (28.06%), HLA-C*04 (20.42%), HLA-C*03 (15.55%), HLA-C*06 (13.04%), HLA-C*12 (5.27%). HLA-DRB1 alleles were HLA-DRB1*07 (21.60%), HLA-DRB1*04 (19.74%), HLA-DRB1*10 (13.15%), HLA-DRB1*03 (10.80%), HLA-DRB1*11 (8.63%). HLA-DQA1 antigen alleles were HLA-DQA1*03 (35.42%), HLA-DQA1*02 (30.89%), HLA-DQA1*05 (21.84%), HLA-DQA1* 06 (10.12%), HLA-DQA1*04 (1.07%). Conclusion The most frequent HLA alleles were HLA-A*01(25.41%), HLA-B*35 (20.54%), HLA-C*07 (28.06%), HLA-DRB1*07(21.60%), HLA-DQA1*03(35.42%) in north Indian population.

HLA-A, -B, -C and -DRB1 Association with Autism Spectrum Disorder Risk: A Sex-Related Analysis in Italian ASD Children and Their Siblings.

Autism Spectrum disorders (ASD) are diagnosed more often in males than in females, by a ratio of about 3:1; this is likely to be due to a difference in risk burden between the sexes and/or to "compensatory skills" in females, that may delay the diagnosis of ASD. Identifying specific risk factors for ASD in females may be important in facilitating early diagnosis. We investigated whether HLA- class I: -A, -B, -C and class II -DRB1 alleles, which have been suggested to play a role in the development of ASD, can be considered as sex-related risk/protective markers towards the ASD. We performed HLA allele genotyping in 178 Italian children with ASD, 94 healthy siblings, and their parents. HLA allele distribution was compared between children with ASD, sex-matched healthy siblings, and a cohort of healthy controls (HC) enrolled in the Italian bone marrow donor registry. Allele transmission from parents to children with ASD and their siblings was also assessed. Our findings suggest that HLA-A*02, B*38, and C*12 alleles are more frequently carried by females with ASD compared to both HC and healthy female siblings, indicating these alleles as potential risk factors for ASD in females. Conversely, the HLA-A*03 allele was more commonly transmitted to healthy female siblings, suggesting it might have a protective effect. Additionally, the HLA-B*44 allele was found to be more prevalent in boys with ASD, indicating it is a potential risk factor for male patients. This is the first Italian study of sex-related HLA association with ASD. If confirmed, these results could facilitate early ASD diagnosis in female patients, allowing earlier interventions, which are crucial in the management of neurodevelopmental disorders.

Moderate Genetic Diversity of MHC Genes in an Isolated Small Population of Black-and-White Snub-Nosed Monkeys (Rhinopithecus bieti).

Genetic diversity is an essential indicator that echoes the natural selection and environmental adaptation of a species. Isolated small populations are vulnerable to genetic drift, inbreeding, and limited gene flow; thus, assessing their genetic diversity is critical in conservation. In this study, we studied the genetic diversity of black-and-white snub-nosed monkeys (Rhinopithecus bieti) using neutral microsatellites and five adaptive major histocompatibility complex (MHC) genes. Two DQA1 alleles, two DQB1 alleles, two DRB1 alleles, two DRB5 alleles, and three DPB1 alleles were isolated from a population. The results indicate that neutral microsatellites demonstrate a high degree of heterozygosity and polymorphism, while adaptive MHC genes display a high degree of heterozygosity and moderate polymorphism. The results also show that balancing selection has prominently influenced the MHC diversity of the species during evolution: (1) significant positive selection is identified at several amino acid sites (primarily at and near antigen-binding sites) of the DRB1, DRB5, and DQB1 genes; (2) phylogenetic analyses display the patterns of trans-species evolution for all MHC loci. This study provides valuable genetic diversity insights into black-and-white snub-nosed monkeys, which dwell at the highest altitude and have experienced the harshest environmental selection of all primates globally since the Pleistocene. Such results provide valuable scientific evidence and a reference for making or amending conservation strategies for this endangered primate species.

DRB1 locus alleles of HLA class II are associated with modulation of the immune response in different serological profiles of HIV-1/Epstein-Barr virus coinfection in the Brazilian Amazon region.

Epstein-Barr virus (EBV) infection involves distinct clinical and serological profiles. We evaluated the frequency of alleles of locus DRB1 of HLA class II in different serological profiles of EBV infection among HIV-1 infected patients. We recruited 19 patients with primary infection, 90 with serological transition and 467 with past infection by EBV, HIV-1 co-infection was 100% in primary infection and approximately 70% in other serological profiles. EBV viral load was quantified by real-time PCR, T lymphocyte quantification and cytokine level analysis were performed by flow cytometry, and HLA locus genotyping was performed by PCR-SSO. The DRB1*09 allele was associated with primary infection (p: 0.0477), and carriers of the allele showed changes in EBV viral load (p: 0.0485), CD8(+) T lymphocyte counts (p: 0.0206), double-positive T lymphocyte counts (p: 0.0093), IL-4 levels (p: 0.0464) and TNF levels (p: 0.0161). This allele was also frequent in HIV-coinfected individuals (p: 0.0023) and was related to the log10 HIV viral load (p: 0.0176) and CD8(+) T lymphocyte count (p: 0.0285). In primary infection, the log10 HIV viral load was high (p: 0.0060) and directly proportional to the EBV viral load (p: 0.0412). The DRB1*03 allele correlated with serological transition (p: 0.0477), EBV viral load (p: 0.0015), CD4(+) T lymphocyte count (p: 0.0112), CD8(+) T lymphocyte count (p: 0.0260), double-negative T lymphocyte count (p: 0.0540), IL-4 levels (p: 0.0478) and IL-6 levels (p: 0.0175). In the serological transition group, the log10 HIV viral load was high (p: 0.0060), but it was not associated with the EBV viral load (p: 0.1214). Past infection was related to the DRB1*16 allele (p: 0.0477), with carriers displaying IgG levels (p: 0.0020), CD4(+) T lymphocyte counts (p: 0.0116) and suggestive CD8(+) T count alterations (p: 0.0602). The DRB01*16 allele was also common in HIV-1 patients with past EBV infection (p: 0.0192); however, the allele was not associated with clinical markers of HIV-1 infection. Our results suggest that HLA class II alleles may be associated with the modulation of the serological profiles of the immune response to Epstein-Barr virus infection in patients coinfected with HIV-1.

Association of Human Leukocyte Antigen (HLA) Class II Alleles of DQB1 (DQB1*03:02) (DQB1*06:02) and DRB1 (DRB1*04:01) with Type-1 Diabetes Patients of Khyber Pakhtunkhwa, Pakistan

Type-1 diabetes (T1D), an autoimmune disease, significantly impacts global health, with varying prevalence across different geographies. This study investigates the association of specific Human Leukocyte Antigen (HLA) Class II alleles, namely DQB1*03:02, DQB1*06:02, and DRB1*04:01, with T1D in the Khyber Pakhtunkhwa (KP) population of Pakistan. Conducted as a 1:1 matched case-control study, this research involved 33 T1D patients and an equal number of age- and gender-matched healthy controls. Our findings reveal a weak association of alleles DRB1*04:01 and DQB1*03:02 with T1D (OR = 2.065 and 1.393, respectively, p > 0.05). DQB1*06:02 allele, which is considered to have a protective effect against T1D was more prevalent in control as compared to cases (93.9% vs 90.9%), however, the association was non-significant (OR 0.645, p > 0.05). These insights contribute to understanding genetic influences on T1D in the KP region and underscore the need for further research with larger, diverse cohorts to refine the genetic markers of T1D risk and protection

The 18th International HLA & Immunogenetics workshop project report: Creating fully representative MHC reference haplotypes.

A fundamental endeavor of the International Histocompatibility and Immunogenetics Workshop (IHIW) was assembling a collection of DNA samples homozygous through the MHC genomic region. This collection proved invaluable for assay development in the histocompatibility and immunogenetics field, for generating the human reference genome, and furthered our understanding of MHC diversity. Defined by their HLA‐A, ‐B, ‐C and ‐DRB1 alleles, the combined frequency of the haplotypes from these individuals is ∼20% in Europe. Thus, a significant proportion of MHC haplotypes, both common and rare throughout the world, and including many associated with disease, are not yet represented. In this workshop component, we are collecting the next generation of MHC‐homozygous samples, to expand, diversify and modernize this critical community resource that has been foundational to the field. We asked laboratories worldwide to identify samples homozygous through all HLA class I and/or HLA class II genes, or through whole‐genome SNP genotyping or sequencing, to have extensive homozygosity tracts within the MHC region. The focus is non‐Europeans or those having HLA haplotypes less common in Europeans. Through this effort, we have obtained samples from 537 individuals representing 294 distinct haplotypes, as determined by their HLA class I and II alleles, and an additional 50 haplotypes distinct in HLA class I or II alleles. Although we have expanded the diversity, many populations remain underrepresented, particularly from Africa, and we encourage further participation. The data will serve as a resource for investigators seeking to characterise variation across the MHC genomic region for disease and population studies. [Correction added on [24 July 2024], after first online publication: the Abstract was inadvertently remove and has been reinstated in this version.]

Frequency of the Main Human Leukocyte Antigen A, B, DR, and DQ Loci Known to Be Associated with the Clearance or Persistence of Hepatitis C Virus Infection in a Healthy Population from the Southern Region of Morocco: A Preliminary Study.

Hepatitis C Virus (HCV) infection represents a significant global health challenge, with its natural course largely influenced by the host's immune response. Human Leukocyte Antigen (HLA) molecules, particularly HLA class I and II, play a crucial role in the adaptive immune response against HCV. The polymorphism of HLA molecules contributes to the variability in immune response, affecting the outcomes of HCV infection. This study aims to investigate the frequency of HLA A, B, DR, and DQ alleles known to be associated with HCV clearance or persistence in a healthy Moroccan population. Conducted at the University Hospital Center Mohammed VI, Marrakech, this study spanned from 2015 to 2022 and included 703 healthy Moroccan individuals. HLA class I and II typing was performed using complement-dependent cytotoxicity and polymerase chain reaction-based methodologies. The results revealed the distinct patterns of HLA-A, B, DRB1, and DQB1 alleles in the Moroccan population. Notably, alleles linked to favorable HCV outcomes, such as HLA-DQB1*0301, DQB1*0501, and DRB1*1101, were more prevalent. Conversely, alleles associated with increased HCV susceptibility and persistence, such as HLA-DQB1*02 and DRB1*03, were also prominent. Gender-specific variations in allele frequencies were observed, providing insights into genetic influences on HCV infection outcomes. The findings align with global trends in HLA allele associations with HCV infection outcomes. The study emphasizes the role of host genetics in HCV infection, highlighting the need for further research in the Moroccan community, including HCV-infected individuals. The prevalence of certain HLA alleles, both protective and susceptibility-linked, underscores the potential for a national HLA data bank in Morocco.

The Polymorphism Analysis of HLA Class II Alleles Based on Next-Generation Sequencing and Prevention Strategy for Allele Dropout

To investigate the accuracy of next-generation sequencing technology (NGS) in detecting the polymorphisms of HLA-DRB1, DQB1, DQA1, DRB3, DRB4, DRB5, DPA1 and DPB1 alleles in randomly-selected unrelated healthy individuals from Shenzhen Han population, investigate the potential reason for HLA-DRB1 allele dropout in routine NGS, and establish an internal quality control system. NGS-based HLA class II genotyping was performed on 1 012 samples using the MiSeqDxTM platform. The suspected missed alleles indicated by the quality control software and HLA-DRB1 homozygotes were confirmed by PCR-SSOP or PCR-SBT methods. A total of 139 alleles were detected, including HLA-DRB1(45), DRB3(7), DRB4(5), DRB5(7), DQA1(17), DQB1(21), DPA1(10) and DPB1(27). HLA-DRB1*09:01(17.09%),15:01(10.72%); DRB3*02:02(25.99%),03:01(10.18%); DRB4*01:03(36.46%); DRB5*01:01(15.42%); DQA1*01:02(20.01%),03:02(17.19%); DQB1*03:01(19.47%),03:03(17.98%), 05:02(11.66%), 06:01(10.67%); DPA1*02:02(54.45%), 01:03(31.18%) and DPB1*05:01(39.13%), 02:01(16.90%) alleles were the most common alleles in Shenzhen Han population (frequencies >10%). There was no statistical difference between the gene frequencies of HLA-DRB1 and DQB1 loci in our study. The HLA Common and Well-Documented Alleles in China (CWD2.4) (χ2=12.68, P >0.05). 94 cases of HLA-DRB1 homozygous samples detected by NGS were retested by PCR-SSOP or SBT method, and one case of allele dropout at HLA-DRB1 locus was found. SBT method confirmed that the allele of DRB1*04:03 was missed. The laboratory internal quality control system was established. Two cases of new alleles were detected and named by WHO Nomenclature Committee for Factors of the HLA System. The HLA genotyping results based on NGS showed a significantly lower ambiguity rate. The HLA class II alleles exhibit genetic polymorphism in the Han population of unrelated healthy individuals in Shenzhen. The independent method based on NGS in clinical histocompatibility testing has limitations and requires internal quality control strategies to avoid allele-dropout events.

HLA-DQB1*05 subtypes and not DRB1*10:01 mediates risk in anti-IgLON5 disease.

Anti-IgLON5 disease is a rare and likely underdiagnosed subtype of autoimmune encephalitis. The disease displays a heterogeneous phenotype that includes sleep, movement and bulbar-associated dysfunction. The presence of IgLON5-antibodies in CSF/serum, together with a strong association with HLA-DRB1*10:01∼DQB1*05:01, supports an autoimmune basis. In this study, a multicentric human leukocyte antigen (HLA) study of 87 anti-IgLON5 patients revealed a stronger association with HLA-DQ than HLA-DR. Specifically, we identified a predisposing rank-wise association with HLA-DQA1*01:05∼DQB1*05:01, HLA-DQA1*01:01∼DQB1*05:01 and HLA-DQA1*01:04∼DQB1*05:03 in 85% of patients. HLA sequences and binding cores for these three DQ heterodimers were similar, unlike those of linked DRB1 alleles, supporting a causal link to HLA-DQ. This association was further reflected in an increasingly later age of onset across each genotype group, with a delay of up to 11 years, while HLA-DQ-dosage dependent effects were also suggested by reduced risk in the presence of non-predisposing DQ1 alleles. The functional relevance of the observed HLA-DQ molecules was studied with competition binding assays. These proof-of-concept experiments revealed preferential binding of IgLON5 in a post-translationally modified, but not native, state to all three risk-associated HLA-DQ receptors. Further, a deamidated peptide from the Ig2-domain of IgLON5 activated T cells in two patients, compared with one control carrying HLA-DQA1*01:05∼DQB1*05:01. Taken together, these data support a HLA-DQ-mediated T-cell response to IgLON5 as a potentially key step in the initiation of autoimmunity in this disease.

An Optimal Multi-Locus HLA-Typing in Potential Donors of Allogeneic Hematopoietic Stem Cells

Background. HLA-typing and matched donor selection as well as the detection of donor-specific anti-HLA antibodies are essential for allogeneic hematopoietic cell transplantation (allo-HSCT). In accordance with the guidelines of the Center for International Blood and Marrow Transplant Research (CIBMTR) optimal HLA-typing is performed on 11 HLA genes (-A, ‐B, ‐C, ‐DRB1, ‐DRB3/4/5, ‐DQA1, ‐DQB1, ‐DPA1, and ‐DPB1) with an adequate coverage aiming to obtain the values at the two-field level.
 Aim. To assess the results of multi-locus HLA-typing in bone marrow/hematopoietic cell donors from the database at the National Research Center for Hematology in terms of their conformance with the CIBMTR guidelines for allo-HSCT and to analyze the frequency and distribution of HLA alleles and multi-locus HLA haplotypes.
 Materials & Methods. The study enrolled 3485 donors who were HLA-typed by next-generation sequencing.
 Results. In all donors, the alleles of HLA class I genes were identified at the fourth-field level (nucleotide sequence). When the results were reduced to the second-field level (amino acid sequence), 61 HLA-A, 92 HLA-B, and 49 HLA-C alleles were detected. The alleles of class II genes were discovered either at the two-field or high-resolution levels. Among the HLA-DRB locus genes, 57 DRB1, 11 DRB3, 6 DRB4, and 5 DRB5 alleles were identified. Also, 23 HLA-DQA1, 30 HLA-DQB1, 14 HLA-DPA1, and 33 HLA-DPB1 alleles were detected. There were reported 3289 different HLA haplotypes of A-B-C-DRB1-DQA1-DQB1-DPA1-DPB1 genes.
 Conclusion. The database created at the National Research Center for Hematology includes potential bone marrow/hematopoietic stem cell donors typed for 11 classical polymorphic genes HLA-A, ‐B, ‐C, ‐DRB1, ‐DRB3/4/5, ‐DQA1, ‐DQB1, ‐DPA1, and -DPB1, which is in line with the guidelines of CIBMTR. The frequency and distribution of HLA alleles and multi-locus HLA haplotypes in our donors correspond to those in populations of European origin. HLA-typing and donor selection with regard to 11 HLA genes will contribute to improving the outcomes of both unrelated and haploidentical HSCTs.

Exploration of potential immune mechanisms in cervical dystonia

BackgroundAlthough there are many possible causes for cervical dystonia (CD), a specific etiology cannot be identified in most cases. Prior studies have suggested a relationship between autoimmune disease and some cases of CD, pointing to possible immunological mechanisms. ObjectiveThe goal was to explore the potential role of multiple different immunological mechanisms in CD. MethodsFirst, a broad screening test compared neuronal antibodies in controls and CD. Second, unbiased blood plasma proteomics provided a broad screen for potential biologic differences between controls and CD. Third, a multiplex immunoassay compared 37 markers associated with immunological processes in controls and CD. Fourth, relative immune cell frequencies were investigated in blood samples of controls and CD. Finally, sequencing studies investigated the association of HLA DQB1 and DRB1 alleles in controls versus CD. ResultsScreens for anti-neuronal antibodies did not reveal any obvious abnormalities. Plasma proteomics pointed towards certain abnormalities of immune mechanisms, and the multiplex assay pointed more specifically towards abnormalities in T lymphocytes. Abnormal immune cell frequencies were identified for some CD cases, and these cases clustered together as a potential subgroup. Studies of HLA alleles indicated a possible association between CD and DRB1*15:03, which is reported to mediate the penetrance of autoimmune disorders. ConclusionsAltogether, the association of CD with multiple different blood-based immune measures point to abnormalities in cell-mediated immunity that may play a pathogenic role for a subgroup of individuals with CD.

Maternal HLA class II alleles and haplotypes associated with altered risk of recurrent pregnancy loss: A case‐control study

AbstractProblemThis study analyzed the contribution of DRB1, DQB1, and DPB1 HLA class II alleles and resulting 3‐locus haplotypes to the overall risk of idiopathic recurrent pregnancy loss (RPL).Method of studyThe study participants included 188 Tunisian participants comprising 84 women with established diagnoses of RPL, and 104 matched multiparous females as controls. Genotyping of HLA alleles was done by PCR‐SSP.ResultsThe allelic frequencies of DPB1, DRB1, and DQB1 were consistent with Hardy‐Weinberg equilibrium among control subjects. Among class II alleles, DRB1*04:01:01 (p = .03), DRB1*08:01:01 (p = .04), and DPB1*01:01:01 (p = .04) were positively associated, whereas DPB1*04:01:01 (p = .012) and DPB1*14:01:01 (p = .006) were negatively associated with risk of RPL. The association of DRB1 and DPB1 alleles with RPL was lost after correction for multiple comparisons. The prevalence of the seven determined DQB1 alleles was not significantly different among case and control groups. Higher prevalence of DRB1*07:01:01∼ DQB1*02:01:01∼DPB1*04:01:01 (0.0417 vs. 0.000; p = .049) coupled with lower prevalence of DRB1*13:01:01∼DQB1*06:01:01∼DPB1*02:01:01 (0.0167 vs. 0.1000; p = .014) haplotypes was noted in women with RPL, thus could be considered as an RPL at‐risk and RPL‐protective haplotype, respectively.ConclusionThe study establishes weak/no contribution of class II alleles and corresponding 3‐locus haplotypes to the altered risk of RPL among Tunisian women and does not confirm previous findings on other Arab‐speaking populations of an HLA association with RPL.

The rare DRB1*04:08-DQ8 haplotype is the main HLA class II genetic driver and discriminative factor of Early-onset Type 1 diabetes in the Portuguese population.

Early-onset Type 1 diabetes (EOT1D) is considered a disease subtype with distinctive immunological and clinical features. While both Human Leukocyte Antigen (HLA) and non-HLA variants contribute to age at T1D diagnosis, detailed analyses of EOT1D-specific genetic determinants are still lacking. This study scrutinized the involvement of the HLA class II locus in EOT1D genetic control. We conducted genetic association and regularized logistic regression analyses to evaluate genotypic, haplotypic and allelic variants in DRB1, DQA1 and DQB1 genes in children with EOT1D (diagnosed at ≤5 years of age; n=97), individuals with later-onset disease (LaOT1D; diagnosed 8-30 years of age; n=96) and nondiabetic control subjects (n=169), in the Portuguese population. Allelic association analysis of EOT1D and LaOT1D unrelated patients in comparison with controls, revealed that the rare DRB1*04:08 allele is a distinctive EOT1D susceptibility factor (corrected p-value=7.0x10-7). Conversely, the classical T1D risk allele DRB1*04:05 was absent in EOT1D children while was associated with LaOT1D (corrected p-value=1.4x10-2). In corroboration, HLA class II haplotype analysis showed that the rare DRB1*04:08-DQ8 haplotype is specifically associated with EOT1D (corrected p-value=1.4x10-5) and represents the major HLA class II genetic driver and discriminative factor in the development of early onset disease. This study uncovered that EOT1D holds a distinctive spectrum of HLA class II susceptibility loci, which includes risk factors overlapping with LaOT1D and discriminative genetic configurations. These findings warrant replication studies in larger multicentric settings encompassing other ethnicities and may impact target screening strategies and follow-up of young children with high T1D genetic risk as well as personalized therapeutic approaches.

Association of HLA-C*07:359 with HLA-A, -B, and -DRB1 alleles in Taiwanese.

It is thought that Taiwanese indigenous people were the "first people" to populate Taiwan (Formosa) having been there for over 5000 years, preceding the Dutch colonization (from 1624 to 1662) and Spanish colonization (from 1626 to 1642). Taiwan's indigenes, represented by Austronesian language speakers, currently constitute approximately 2% of the total population in Taiwan. It is unknown whether they evolved from Taiwan's Paleolithic or Neolithic cultures, arrived during or after the Neolithic period from China or Southeast Asia or both. HLA studies on the Taiwanese indigenous population have found several intriguing genetic information showing one or two relatively frequently observed alleles and a small number of relatively less frequently observed ones. We report here a relatively frequently observed HLA-C*07:359 allele in the Taiwanese indigenous population, its linkage with HLA-B*39:01, and its probable associated HLA haplotype in two Taiwanese indigenous families. HLA-C*07:359 is a rarely observed allele in the HLA-C locus in the world populations. The objective of this study is to report the allele HLA-C*07:359 that is more frequently found in the Taiwanese population, especially in the Taiwanese indigenous people, to demonstrate that it has a close linkage with HLA-B*39:01 allele in the HLA-B locus and to show the plausible deduced HLA-A-C-B-DRB1-DQB1 haplotypes in association with HLA-C*07:359 in two families of Taiwanese indigenous unrelated individuals. The samples were peripheral whole blood, with dipotassium ethylenediaminetetraacetic acid and/or acid citrate dextrose anticoagulation additives. The sequence-based typing method was employed to confirm the low incidence of the allele of HLA-C*07:359 observed in Taiwanese. Polymerase chain reaction was carried out to amplify exons 2, 3, and 4 of the HLA-A,-B,-C,-DRB1 and-DQB1 loci with group-specific primer sets. Amplicons were sequenced using the BigDye Terminator Cycle Sequencing Ready Reaction Kit in both directions according to the manufacturer's protocol. C*07:359 is an uncommon allele in the HLA-C locus in the world general population, according to our literature review. However, in this study, it is observed in the general Taiwanese population (frequency 0.41%), especially in the Taiwanese indigenous people at a frequency of 0.23%. In addition, we deduced two probable HLA haplotypes in association with C*07:359 in two indigenous families: A*24:02-C*07:359-B*39:01-DRB1*04:36 and A*24:02-C*07:359-B*39:01-DRB1*04:04. The two deduced HLA haplotypes associated with the uncommon C*07:359 allele that we report here are valuable for HLA tissue typing laboratories for reference purposes and for stem cell transplantation donor search coordinators to determine the likelihood of finding compatible donors in unrelated bone marrow donor registries for patients bearing the uncommon HLA allele. Since C*07:359 was found mostly in the Taiwanese indigenous population, we think the allele and its haplotypes we report here are important in population and anthropological studies.

Analysis of Human Leukocyte Antigen Frequency among Renal Transplant Recipients and Donors in Nepal

ABSTRACT Background and Objectives: Kidney transplants are effective for advanced renal failure, but graft rejection can occur when the recipient’s immune system misidentifies the kidney as a foreign object. Human leukocyte antigen (HLA), a component of the host’s immunological defense system, acts as a barrier to graft rejection. Selecting potential kidney recipients and donors for transplantation requires careful consideration of histocompatibility for the HLA-A, HLA-B, and HLA-DRB1 antigens. Mismatches between donors and recipients prolong transplant therapy, leading to lower graft survival and higher mortality. The objective of the study was to analyze HLA-A, HLA-B, and HLA-DRB1 antigens frequency in live-related renal transplant recipients and donors visiting the Department of Histocompatibility and Immunopathology at the National Public Health Laboratory, Teku, Kathmandu, Nepal. Methods: A retrospective study was conducted by using data from 104 renal transplant recipients and donors whose samples had previously been collected, processed, and analyzed to identify the Class I loci (HLA-A and HLA-B) and Class II loci (DRB1) between November 2021 and February 2024. Results: The study found that the majority of donors were female, and the majority of recipients were male. In this study, 10, 17, and 12 different HLA-A, B, and DRB1 alleles were found in recipients and donors. Alleles found more frequently are A*11 (25.00%), A*24 (23.08%), sB*15 (22.60%), B*35 (12.98%), DRB1*15 (22.60%), and DRB1*12 (21.63%). Conclusions: The study suggests that both donors and recipients of renal transplants in Nepal have a diverse HLA antigen distribution, which could aid in selecting a genetically closer group as potential matched donors for transplant recipients.

HLA class II DRB1, DQA1, DQB1 loci in patients with HIV infection and tuberculosis in a Latvian cohort group.

Until the COVID-19 pandemic, tuberculosis (TB) was the leading cause of death from a single infectious agent, ranking above HIV/AIDS. It is also the key cause of death among people infected with HIV. Tuberculosis incidence in Latvia has decreased by 25% during the last 30 years, but the mortality level of TB remains significant. The HLA class II genes are responsible for antigen presentation and regulation of immune responses, which plays an important role in individual susceptibility to infection disease. Whether or not differential HLA polymorphism contributes to TB with HIV infection and TB without HIV infection in Latvian patients is unknown. For the detection of HLA class II DQA1, DQB1, and DRB1 alleles a total of 616 subjects were enrolled, including 80 primary active TB (PATB) patients, 168 HIV-1/TB patients, 168 HIV-1 patients and 200 HC individuals. For immunodeficiency caused by TB, HIV-1 or HIV-1/TB coinfection, alleles DRB1*12:01, 14:01, 16:01, DQA1*01:02, 01:03, 02:01, 06:01, DQB1*03:03, 06:01 are identified as protective, but DRB1*07:01, 11:01, 15:01, DQA1*02:01, 03:01, DQB1*03:01, 05:01 are identified as risk alleles. The results of our experimental pilot studies demonstrated that HLA class II genes may contribute to the genetic risk of TB and HIV-1/TB co-infection, possibly by reducing the presentation of protective Mycobacterium tuberculosis antigens to T-helpers. It is necessary to conduct repetitive, multicentre, and large sample studies in order to draw more scientific conclusions and to confirm the relationship between TB, HIV and HIV-1/TB co-infection susceptibility and gene polymorphisms.

Генетические предикторы выживаемости и развития MACE в остром периоде инфекции, вызванной SARS-COV-2, у пациентов высокого кардиоваскулярного риска

Introduction. Despite the fact that the SARS-CoV-2 virus is highly contagious, the clinical manifestations of the disease caused by it can have significant differences: from a low-symptom course to extremely severe forms with the development of a fatal outcome. It is obvious that the observed polymorphism of the development of infection caused by SARS-CoV-2 is due, among other things, to genetic factors. These include single-nucleotide polymorphisms of genes involved in the stages of the pathogenesis of infection: from the penetration of the virus into target cells, the expression of its RNA to the response of the host organism. The study of genetic predictors that cause changes in susceptibility to the SARS-CoV-2 virus and differences in the severity of infection will help to better understand the pathogenesis of this disease and give an idea of promising areas of therapy and prevention. Aim. To study the relationship of genetic biomarkers with the severity of infection caused by SARS-CoV-2, cardiovascular complications and the risk of death in the early period of the disease. Design. A single-center retrospective study. Materials and methods. The study included 164 patients (90 men, 74 women) with infection caused by SARS-CoV-2. All patients were classified as high and very high cardiovascular risk. Concomitant somatic pathology: arterial hypertension in 164 (100%), coronary heart disease in 80 (48.9%), alimentary obesity in 100 (61%), prediabetes in 52 (31.74%), chronic kidney disease in 34 (20.7%) patients. At the first stage of the study, the relationship of genetic biomarkers with the severity of the disease was evaluated, at the second — with cardiovascular complications, and at the third — with the onset of death. Results. In the group of patients with severe disease, variant DD of ACE Alu I/D gene polymorphism, rs4646994 (p = 0.004), variant GG of IL-10 polymorphism 1082 G/A, rs1800896 (p = 0.043), allele *11 HLA-DRB1 (p = 0.015) were significantly more common. The genetic predictors of the development of cardiovascular complications were the genotype DD of the ACE gene (rs4646994) (p = 0.038), the allele *3 HLA-DRB1 (p = 0.041), the allele *13 HLA-DRB1 (p = 0.047) was less common. When searching for a correlation between the selected genetic biomarkers and mortality, only a negative contribution of the ACE Alu I/D polymorphism variant DD, rs4646994 (p = 0.015) was revealed. The survival analysis showed that in the DD variant of the ACE Alu polymorphism I/D, rs4646994, the median survival rate is lower than in the II variant (13 (9–15) days and 21 (12–n/o) days, respectively (p = 0.03)), and lower than in the ID (31 variant (14–n/ o) day (p < 0.0001)). The survival rate of patients with the heterozygous variant of the polymorphism MTRR –66 A/G, rs1801394 was 11.5 (9–16) days, with variant AA — 7 (3–n/o), and with variant GG — 6 (4–14), p = 0.013. With the *16 HLA DRB1 allele, survival was only 5.5 (2–n/o) days versus 22 (17–n/o) days in patients without it, p = 0.04. Conclusion. Predictors of an increased risk of severe infection caused by SARS-CoV-2 include the DD variant of the ACE Alu I/D gene polymorphism, rs4646994, the GG variant of the IL-10 1082 G/A gene polymorphism, rs1800896 and the *11 HLA-DRB1 allele. The negative effect of the DD variant of the polymorphism of the ACE Alu I/D gene, rs4646994, the *3 HLA-DRB1 allele and the protective effect of the *13 HLA-DRB1 allele have been proven in relation to the overall risk of major cardiovascular complications. The carriage of the *16 HLA-DRB1 allele and the DD variant of the ACE Alu I/D gene polymorphism, rs4646994, correlate with an increased risk of early hospital mortality in patients. At the same time, the heterozygous variant of the MTRR –66 A/G polymorphism, rs1801394, is a protective biomarker and is associated with better survival. Key words: COVID-19, SARS-CoV-2 virus, mortality, cardiovascular complications, cardiovascular risk, genetic biomarkers

Diversity of MHC class II DRB alleles and mitochondrial DNA in northern and eastern European pine marten, Martes martes (Mammalia: Mustelidae)

Abstract Four mitochondrial phylogroups are distinguished in the European pine marten (Martes martes), two of which, FNR1/2, are shared with the more easterly sister species, the sable (Martes zibellina). Here, we found that the phylogroup frequencies differed markedly between the southern Finland and western Russia populations in the eastern part of the range of Martes martes, suggesting differential introgression from M. zibellina in these regions. We also examined the diversity of a protein-coding gene, MHC class II DRB, in these two Martes species. We detected 16 functional Martes martes DRB alleles (Mama-DRBs), including several codons that seem to have undergone positive selection, and eight presumed pseudogenes (Mama-DRB*PSs); some alleles/pseudogenes were geographically widespread and others restricted. In a broader carnivoran DRB tree, all Mama-DRBs grouped within a mustelid clade, four in a basal group comprising alleles from early-diverged species and the others in a derived group containing alleles from more recently diverged species. Many alleles showed trans-species polymorphism, suggesting that Mama-DRBs have evolved under pathogen-driven balancing selection. Three of six Mama-DRBs and one of four pseudogenes shared with Martes zibellina were restricted to the FNR1/2 mitochondrial DNA phylogroups, pointing to the possibility that genetic introgression from Martes zibellina might have contributed to Mama-DRB diversity and thus adaptability.