Moroccan study of HLA (-A, -B, -C, -DR, -DQ) polymorphism in 647 unrelated controls: Updating data

HLA class I and class II alleles and haplotypes of Algerian population from Algiers and neighbouring area

In this study, we aimed to investigate the current genetic diversity and provide additional insights into the origins of the Algerian population by analyzing the frequencies of HLA -A,-B,-DRB1,-DQB1 alleles and associated haplotypes. We analyzed 1,082 unrelated healthy Algerian individuals, who were potential kidney donors, recruited and assessed in the Immunology Department of CHU Mustapha in Algiers over a 10-year period (2009-2019). HLA genotyping was performed by Polymerase Chain Reaction Sequence Specific Primers (PCR-SSP). The allelic typing estimate and haplotype frequencies were calculated using the R studio® software and Haplotype frequency estimation from the website https://hla-net.eu/. We identified a total of 20 HLA-A alleles, 31 HLA-B alleles, 13 HLA-DRB1 alleles and5 HLA-DQB1 alleles. Regarding the allele frequency, the haplotype frequency and the distribution with other population database, we were able to provide a description of Algerian genetic background and draw some anthropogenetic conclusions. This study of HLA polymorphism in the Algerian population shows a strong genetic similarity with the populations of southern Europe and North Africa (Morocco, Tunisia and Libya) with which it has shared a common history since antiquity. In addition to its contribution to anthropogenetics, our study, serve as a reference database for studies exploring associations between the HLA system and certain pathologies.

HLA haplotype frequencies and diversity in patients with hemoglobinopathies

The genetic diversity of the human leukocyte antigen (HLA) system was shaped by evolutionary constraints exerted by environmental factors. Analyzing HLA diversity may allow understanding of the underlying pathways and offer useful tools in transplant setting. The aim of this study was to investigate the HLA haplotype diversity in patients with sickle cell disease (SCD, N = 282) or β-thalassemia (β-Thal, N = 60), who received hematopoietic cell transplantation (HCT) reported to Eurocord and the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC). We identified 405 different HLA-A-B-DRB1 haplotypes in SCD and 108 in β-Thal patients. Using data from African and European populations of the "1000 Genomes Project" for comparison with SCD and β-Thal, respectively, we found that the haplotypes HLA-A*30-B*14-DRB1*15 (OR 7.87, 95% CI: 1.66-37.3, p b = 0.035), HLA-A*23-B*08 (OR 6.59, 95% CI: 1.8-24.13, p b = 0.023), and HLA-B*14-DRB1*15 (OR 10.74, 95% CI: 3.66-31.57, p b = 0.000) were associated with SCD, and the partial haplotypes HLA-A*30-B*13 and HLA-A*68-B*53 were associated with β-Thal (OR 4.810, 95% CI: 1.55-14.91, p b = 0.033, and OR 17.52, 95% CI: 2.81-184.95, p b = 0.011). Our results confirm the extreme HLA genetic diversity in SCD patients likely due to their African ancestry. This diversity seems less accentuated in patients with β-Thal. Our findings emphasize the need to expand inclusion of donors of African descent in HCT donor registries and cord blood banks.

HLA-C Genotyping Reveals Haplotype C*07 as a Potential Biomarker of Late Psoriasis Onset in Moroccan Patients

Psoriasis still has an unknown etiology. Genetic predisposition shows the association between HLA-Cw6 allele and psoriasis. Although biotherapies have been proven effective in psoriasis treatment, methotrexate (MTX) is still used as a first-line systemic therapy due to its efficacy/affordability, but the differential response to MTX is mostly related to interindividual genetic variability and remains an issue. Our study aimed to analyze HLA-C allele frequencies in a sample of Moroccan psoriatic patients and assess the therapeutic response to MTX. Whole blood of 54 Moroccan psoriatic patients was collected and DNA was extracted. Patients' HLA-C locus was genotyped by PCR-SSO. Results were analyzed with Luminex xMAP Technology and Match-it DNA Evolution 3.4. HLA-C typing results of 77 sex- and age-matched unrelated non-psoriatic healthy subjects were included. We observed no difference in the allelic distribution of HLA-C between patients and healthy controls, suggesting that none of the HLA-C alleles were significantly associated with psoriasis. Moreover, the HLA-C*07 allele was associated with a late age at disease onset (>30 years old) (p = 0.007). No statistically significant association was found between HLA-C allele expression and response to MTX, despite a higher frequency of HLA-C*06 in responders compared to non-responders. Thus, HLA-C*07 could be a biomarker of late psoriasis onset in the Moroccan population.

Explore the distribution of (rs35742686, rs3892097 and rs1065852) genetic polymorphisms of cytochrome P4502D6 gene in the Moroccan population

Background

The CYP2D6 gene encodes a crucial enzyme involved in the metabolic pathways of many commonly used drugs. It is a highly polymorphic gene inducing an interethnic and interindividual variability in disease susceptibility and treatment response. The aim of this study is to evaluate the frequency of the three CYP2D6 most investigated alleles (CYP2D6*3, CYP2D6*4, and CYP2D6*10 alleles) in Morocco compared to other populations.

This study enrolled 321 healthy Moroccan subjects. CYP2D6 genotypes and allele frequencies were assessed using a restriction fragment length polymorphism–polymerase chain reaction genotyping method. The Principal Component Analysis (PCA) and dendrogram were conducted to evaluate genetic proximity between Moroccans and other populations depending on CYP2D6 allele frequencies.

Results

According to the current study, the results observed the homozygous wild type of the three studied SNPs were predominant among the Moroccan population, while 1.4% of Moroccans carried the CYP2D6*4 allele responsible for a Poor Metabolizer phenotype and associated with low enzyme activity which may induce a treatment failure. The PCA and cluster dendrogram tools revealed genetic proximity between Moroccans and Mediterranean, European and African populations, versus a distancing from Asian populations.

Conclusion

The distribution of CYP2D6 polymorphisms within Morocco follows the patterns generally found among the Mediterranean, European and African populations. Furthermore, these results will help to lay a basis for clinical studies, aimed to introduce and optimize a personalized therapy in the Moroccan population.

Association between the Lymphotoxin-α A252g Gene Polymorphism and the Risk of Sepsis and Mortality: A Meta-Analysis

Background

The association between the lymphotoxin-α (LTA) A252G polymorphism and sepsis risk has been extensively studied, but the results have been controversial. This study is aimed at investigating the overall association between the LTA A252G polymorphism and the risk of sepsis/septic shock and sepsis-related mortality.

Methods

We searched the PubMed and EMBASE databases to identify studies that investigated the association between the LTA A252G polymorphism and risks of sepsis, septic shock, and mortality. The relevant data were extracted, and statistical analyses were performed using the Revman 5.0 and STATA 12 software.

Results

A total of 32 publications were included in the meta-analysis. The results demonstrated that the LTA A252G polymorphism showed no significant association with sepsis risk (GG+GA vs. AA: OR = 0.92, 95%CI = 0.79–1.07, p = 0.27) or with sepsis shock risk (GG+GA vs. AA: OR = 1.01, 95%CI = 0.84–1.22, p = 0.91). However, in the subgroup analyzed by ethnicity, the LTA A252G polymorphism significantly decreased sepsis risk in the Asian population for the recessive model [GG vs. GA+AA: OR = 0.82, 95%CI = 0.68–0.99, p = 0.04] but not in the Caucasian population. Moreover, comparisons between sepsis patients who survived and those who did not suggested that the LTA A252G polymorphism decreases the risk of mortality [GG+GA vs. AA: OR = 0.57, 95%CI = 0.41–0.80, p < 0.01].

Conclusion

Our results suggested that the A252G polymorphism in the LTA gene decreased the risk of sepsis in Asians and may reduce mortality in septic individuals.

Genetic Distribution of the LTA +252 A>G and TNFA -308 G > A Polymorphisms in the Moroccan Population

Introduction: The LTA and TNFA genes encode key proinflammatory cytokines with diverse activities in the immune responses. Single nucleotide polymorphisms (SNPs) in the LTA rs909253 (+252 A > G) and TNFA rs1800629 (-308 G > A) genes have been associated with susceptibility to many complex diseases. The aim of this study was to assess the frequency for these two key polymorphisms in the Moroccan population. Materials and Methods: A total of 338 unrelated healthy Moroccan subjects were genotyped for the two alleles using a restriction fragment length polymorphism-polymerase chain reaction method. Results: The LTA (+252 A > G) and TNFA (-308 G > A) were the most common alleles with 67.9% and 74.8% frequencies, respectively. In addition to the linkage disequilibrium between the two SNPs, significant differences in allele frequencies were observed in Moroccan population compared with Mediterraneans, Europeans, Africans, South Americans, and Asians (p < 0.05). Finally, genetic proximities between Moroccan, European, and West African populations were found by means of the principal component analysis. Conclusion: The LTA +252 A>G and TNFA -308 G > A polymorphisms among Moroccan population follow the patterns commonly encountered in other Mediterranean, European, and African populations. The result of this study could contribute in developing a genetic database on the healthy Moroccan population.

Using next-generation sequencing for characterising HLA-DRB1 and DQB1 loci in a cohort of Colombian women

The Colombian population is characterised by a high genetic diversity, secondary to the ethnic mixture arising from colonisation. Unfortunately, few reports are available regarding HLA-DRB1 and DQB1 diversity in Colombia to date. HLA-DRB1 and DQB1 diversity was identified in this study using next-generating sequencing (NGS) on a cohort of Colombian women. Cervical samples taken from 276 women were used for typing DRB1 and DQB1 loci by Illumina MiSeq. Allele and haplotype frequencies were calculated using an expectation-maximisation algorithm. Hardy-Weinberg Equilibrium and linkage disequilibrium (LD) between loci were evaluated. Forty-seven DRB1 alleles and 14 DQB1 alleles were identified. DRB1*04:07:01G and DQB1*03:02:01G alleles occurred most frequently in the target population. Significant LD was found in 44 out of the 144 identified haplotypes, within which DRB1*04:07:01G-DQB1*03:02:01G occurred most frequently (6.56%). The alleles and haplotypes found with NGS agreed with that found in previous reports involving lower resolution for the Colombian population, and greater genetic variability was found, especially concerning DRB1. Comparing allele and haplotype frequency distribution in the target population to that of other populations denoted HLA system intra- and inter-population diversity.

HLA typing and haematopoietic stem cell transplantation in the histocompatibility unit of the Ibn Sina University Hospital in Rabat (Morocco)

PURPOSE OF STUDY

This study focuses on the search for a suitable related HLA-matched donor of haematopoietic stem cells in the context of allogeneic transplantation in Morocco. The aim of this work is to establish whether the related donor can meet graft needs in Moroccan patients.

PATIENTS AND METHODS

429 families (429 recipients and 965 donors) benefited from HLA typing, using microlymphocytotoxicity, polymerase chain reaction-sequence specific primer and/or high-resolution polymerase chain reaction-specific sequence oligonucleotide.

RESULTS

The recipients and donors are mostly men over 18 years of age. In total, 86.8% of the recipients have between 1 and 3 donors who are 96% of the collaterals. Malignant haemopathies account for 54% of allograft indications. Benign haemopathies are more frequent than malignant in children, whereas the profile is reversed in adults. Fifty percent of recipients have an HLA identical donor in their siblings and 42% and HLA haplo identical donor. The HLA typing of the recipients and the donors reveals very large polymorphism of the population.

CONCLUSION

The related donor of haematopoietic stem cells represents an important source of grafts but will not be able to satisfy all the needs of Morocco. The creation of national unrelated voluntary donors will open up new possibilities for recipients who do not have a compatible donor within his relatives.

North African-Mediterranean HLA genetic contribution in a population of the kidney transplant waiting list patients of Canary origin (Gran Canaria)

The peopling of the Canary Islands has been widely debated. The mitochondrial DNA and Y-chromosome data support the idea of a Berber genetic origin coming from the North of Africa (maternal) and a later contribution of the Spanish invaders (paternal). The frequencies of the HLA class II alleles from the Tenerife Island (another Canary Island) have previously been published, postulating a Berber and Atlantic/Iberian contributions to the current population. The HLA class I and class II allele frequencies, haplotype frequencies and phylogenetic comparisons were performed in 215 unrelated individuals from Gran Canaria Island (belonging to the kidney transplant waiting list), with at least three generations of ancestors from Canary Islands, in order to study the different ethnical HLA contributions to the genetic background of the Canary Islanders. Results showed the presence of a compound HLA haplotype of putative Phoenician-Berber origin, A*33:01-C*08:02-B*14:02-DRB1*03:01-DQB1*02:01, likely coming from the combination of haplotypes A*30:02-C*05:01-B*18:01-DRB1*03:01-DQB1*02:01 and A*33:01-C*08:02-B*14:02-DRB1*01:02-DQB1*05:01 of North African (probably Berber) and West Asian Mediterranean (probably Phoenician) origins, respectively. The latter haplotypes and others from the same origin (Berber/Phoenician) are also present in the population studied. Besides, other contributions from the North of Europe, North England-Iberian (Atlantic contribution), and Western Europe/Mediterraneans (Spanish colonization) are also discussed. These data conclude that the current genetic background of the Canary Islands inhabitants has been generated over the years by different ways with an original Phoenician-Berber substrate and several genetic contributions generated in different invasions.

HLA-A, -B, -C and -DRB1 allele and haplotype frequencies in the Macedonian population based on a family study

AIM

The aim of this study was to determine HLA allele and 2-, 3- and 4-loci haplotype frequencies in a sample from Macedonian population with defined haplotypes based on family history.

MATERIAL AND METHODS

We analysed 286 unrelated individuals with Macedonian origin, parents of patients who needed stem cell transplantation, in the period of 01.01.2003 till 31.12.2016. Allele and haplotype frequencies, as well as Hardy-Weinberg equilibrium were calculated using the Arlequin3.5 software. Population comparison was calculated using the PHYLIP software.

RESULTS

We identified 18 HLA-A, 26 HLA-B, 13 HLA-C and 13 HLA-DRB1 allele group families. The most frequent allele groups in our population were HLA-A*02 (29.0%), HLA-A*24 (13.8%), HLA-B*35 (16.1%), HLA-B*51 (14.7%), HLA-B*18 (14.7%), HLA-C*07 (27.9%), HLA-DRB1*11 (25.5%) and HLA-DRB1*16 (14.8%). The most frequent four loci haplotype was HLA-A*01-B*08-C*07-DRB1*03 (2.7%). Our comparison showed that the Macedonian population is closely related to the neighbouring countries in the Balkan Peninsula.

CONCLUSION

This study provides data about the HLA diversity in the Macedonian population, which can be very important in the process of unrelated donor search, and in addition yields control group for future disease association studies in our population.

HLA Typing and Celiac Disease in Moroccans

Genetic and environmental factors are responsible for differences in the prevalence of some diseases across countries. Human leukocyte antigen (HLA) allele frequencies in North African populations show some differences in their distribution compared to Europeans, Mediterraneans, and sub-Saharans, and some specific alleles and haplotypes could be clinically relevant. Celiac disease (CD) has been fast increasing in prevalence in North Africa; but few immunogenetic data are available for this area, in which a high prevalence of the disease has been described. In this report, we assess and discuss results of HLA class II (HLA-DQA1/DQB1/DRB1) typing in Moroccan patients with CD and compare them with a control population from Morocco—genetically well characterized—and with other North African, Mediterranean, and European populations. The classical HLA-DQ associations were confirmed in Moroccans with CD. The high frequency of DQ2.5 homozygosity (45.2%) found in Moroccans with CD was noteworthy as compared with other populations (23%–32%). The genetic risk gradient for CD, identified by previous studies, has been confirmed in Moroccans with some differences, mainly concerning DQ8 genotypes. This study provides the immunogenetic framework of CD in Moroccans and confirms the need to learn more about associations with additional HLA and non-HLA genetic factors.

The investigation of the origin of Southern Tunisians using HLA genes

The south of Tunisia is characterized by marked ethnic diversity, highlighted by the coexistence of native Berbers with Blacks, Jews and Arab-speaking populations. Despite this heterogeneity, genetic anthropology studies investigating the origin of current Southern Tunisians were rarely reported. We examined human leukocyte antigen (HLA) class I (A, B) and class II (DRB1, DQB1) gene profiles of 250 unrelated Southern Tunisians, and compared them with those of Arab-speaking communities, along with Mediterranean and sub-Sahara African populations using genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. In total, 137 HLA alleles were detected, which comprised 32 HLA-A, 52 HLA-B, 32 DRB1 and 21 DQB1 alleles. The most frequent alleles were HLA-A*02:01(18.02%), HLA-B*50:01 (9.11%), HLA-DRB1*07:01 (22.06%) and HLA-DQB1*02:01 (17.21%). All pairs of HLA loci show significant linkage disequilibrium. The four loci depict negative F_nd (the normalized deviate of the homozygosity) values indicating an overall trend to balancing selection. Southern Tunisians appear to be closely related to others Tunisian populations including Berbers, North Africans and Iberians. On the contrary, Southern Tunisians were distinct from Palestinian, Lebanese and Jordanian Middle Eastern Arab-speaking population, despite the deep Arab incursions and Arabization that affected Southern Tunisia. In addition, Southern Tunisians were distant from many sub-Saharan communities, evidenced by genetic distance analysis. Collectively, this indicates a limited genetic contribution of Arab invasion and Black caravans on the makeup of Southern Tunisian gene pool.

CD1A, D and E gene polymorphisms in a North African population from Morocco

CD1 molecules are specialized in capturing and presenting lipids and glycolipids to distinct subsets of T and NKT cells. Glycolipid presentation could play a significant role in the immune response against microbial infections. There are five closely linked CD1 genes in humans, named CD1A, B, C, D, and E, which all show a limited polymorphism. In this study, exon 2 polymorphisms of CD1A, CD1D and CD1E were investigated and allele, genotype and haplotype frequencies of these loci were reported in a Moroccan population. A comparison with allele, genotype and haplotype frequencies observed in other geographic areas was also performed. Results confirmed the presence of ethnic differences in CD1 polymorphism, mainly in CD1D (in this population two additional CD1D variant alleles, CD1D(∗)03 and CD1D(∗)04, were described) and E genes. These data could be useful to evaluate a possible pathogenetic role of CD1 in diseases. Increasing the knowledge in this field may offer possibilities for the development of new immunotherapeutic approaches.

An initial examination of the potential role of T-cell immunity in protection against feline immunodeficiency virus (FIV) infection

The importance of vaccine-induced T-cell immunity in conferring protection with prototype and commercial FIV vaccines is still unclear. Current studies performed adoptive transfer of T cells from prototype FIV-vaccinated cats to partial-to-complete feline leukocyte antigen (FLA)-matched cats a day before either homologous FIVPet or heterologous-subtype pathogenic FIVFC1 challenge. Adoptive-transfer (A-T) conferred a protection rate of 87% (13 of 15, p < 0.001) against FIVPet using the FLA-matched T cells, whereas all 12 control cats were unprotected. Furthermore, A-T conferred protection rate of 50% (6 of 12, p<0.023) against FIVFC1 using FLA-matched T cells, whereas all 8 control cats were unprotected. Transfer of FLA-matched T and B cells demonstrated that T cells are needed to confer A-T protection. In addition, complete FLA-matching and addition of T-cell numbers > 13 × 10(6) cells were required for A-T protection against FIVFC1 strain, reported to be a highly pathogenic virus resistant to vaccine-induced neutralizing-antibodies. The addition of FLA-matched B cells alone was not protective. The poor quality of the anti-FIV T-cell immunity induced by the vaccine likely contributed to the lack of protection in an FLA-matched recipient against FIVFC1. The quality of the immune response was determined by the presence of high mRNA levels of cytolysin (perforin) and cytotoxins (granzymes A, B, and H) and T helper-1 cytokines (interferon-γ [IFNγ] and IL2). Increased cytokine, cytolysin and cytotoxin production was detected in the donors which conferred protection in A-T studies. In addition, the CD4(+) and CD8(+) T-cell proliferation and/or IFNγ responses to FIV p24 and reverse transcriptase increased with each year in cats receiving 1X-3X vaccine boosts over 4 years. These studies demonstrate that anti-FIV T-cell immunity induced by vaccination with a dual-subtype FIV vaccine is essential for prophylactic protection against AIDS lentiviruses such as FIV and potentially HIV-1.

[The HLA system in the Moroccan population: General review]

The Moroccan population is an interesting study model of Human Leukocyte Antigen (HLA) polymorphism given its ethnic and genetic diversity. Through an analysis of the literature, this work proposes to establish a balance of knowledge for this population in the field of histocompatibility: HLA diversity, anthropology, transplantation and HLA associations and diseases. This analysis shows that the HLA system has not been fully explored within the Moroccan population. However, the results obtained allowed us to initiate a database reflecting the specific healthy Moroccan population HLA polymorphism to identify immigration flows and relationships with different people of the world and to reveal the association of certain HLA alleles with frequent pathologies. We also propose to analyze the reasons hindering the development of this activity in Morocco and we will try to identify some perspectives.