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.

SNPs in the TNF-α gene promoter associated with Behcet's disease in Moroccan patients.

OBJECTIVE: Behçet's disease (BD) is a multisystemic inflammatory disease, mainly characterized by recurrent oral and genital ulcers (GUs), skin lesions and uveitis. Several genetic factors such as the TNF-α gene have been evaluated as contributors to the pathogenesis of BD. We aimed to evaluate the association between six TNF-α SNPs and susceptibility to BD, or the major clinical manifestations, in Moroccan patients. The six SNPs studied were: c.-1211C>T (rs1799964), c.-1043C>A (rs1800630), c.-1037C>T (rs1799724), c.-556G>A (rs1800750), c.-488G>A (rs1800629) and c.-418G>A (rs361525), known as -1031T>C, -863C>A, -857C>T, -376G>A, 308G>A and -238G>A, respectively. METHODS: SNPs were genotyped by direct sequencing in 120 unrelated Moroccan BD and 112 ethnically matched healthy controls. Allele and genotype distributions were compared between groups using chi-square or Fisher's exact tests. RESULTS: The frequency of the -1211C allele was higher in (i) BD patients than in controls [P = 0.02, odds ratio (OR) = 1.68, 95% CI 1.10, 2.56] and in (ii) patients with GUs than in those without (P = 0.002, OR = 3.84, 95% CI 1.55, 9.49). The -418A frequency was lower in patients with uveitis (P = 0.0003, OR = 0.19, 95% CI 0.07, 0.5). CONCLUSION: We report the first association between BD and TNF-α SNPs in Moroccan patients. We mainly observed that -1211C constitutes a susceptibility allele for both BD and GU, as previously reported for other populations. The -418A allele could be considered as a good prognostic factor for anterior uveitis, in Moroccan BD patients.

Polymorphism of human leukocyte antigen-A, -B, and -DRB1 in a Moroccan population from Casablanca: study of the allelic and the haplotypic frequencies.

We have studied the distribution of HLA-A, -B and DRB1 alleles and haplotypes by sequence specific oligonucleotide amplification in a sample of 125 unrelated healthy Moroccan individuals from Casablanca in Morocco. The city of Casablanca is known of its big ethnic diversity, especially Arabs and Berbers. The most frequent alleles found were: HLA-A*02 (18.4%), -A*01 (11.2%), -A*03 (10.8%), -B*51 (8.06%),-B*44 (7.66%), -B*08 (6.85%), -DRB1*04 (15.98%), DRB1*03 and DRB1*07 (13.92%) and -DRB1*01 (10%). High frequency for five two-locus haplotypes was observed for A*03-B*51 (5%), A*02-DRB1*03 (5.5%), A*02-DRB1*04 and A*01-DRB1*04 (5%) and B*35-DRB1*04 (4%). No predominant haplotype was observed for HLA A-B-DRB1. Our results confirm and extend the current knowledge about genetic pattern of the Moroccan of Casablanca. This study will serve as a reference for further anthropological studies, as well as studies of HLA and disease associations in the Moroccan population.

HLA-B*27 allele associated to Behçet's disease and to anterior uveitis in Moroccan patients.

Human leukocyte antigen HLA-B51 is the most strongly associated gene with Behçet disease (BD) in different ethnic populations. We analyze the influence of HLA-B alleles in BD predisposition in Moroccan population and its association with clinical manifestations. The HLA-B phenotype frequencies were analyzed by serologic HLA class I typing and by polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) reverse dot blot hybridization in 120 unrelated Moroccan patients: all of whom fulfilled the international study group criteria for Behçet's disease, and in 112 ethnically matched healthy controls. Besides HLA-B*51 allele (20%), a significant increased frequency of the HLA-B*27 allele was found in Moroccans patients with Behçet's disease when compared to controls (13.3% of patients versus 2.7% of controls, chi square = 8.75, OR = 5.59, 95% IC [1.58-19.75] and particularly in the patients who presented an anterior uveitis (25% vs. 5.5%, p < 0.005).

The 752delG26 mutation in the RFXANK gene associated with major histocompatibility complex class II deficiency: evidence for a founder effect in the Moroccan population.

Major histocompatibility complex class II plays a key role in the immune response, by presenting processed antigens to CD4+ lymphocytes. Major histocompatibility complex class II expression is controlled at the transcriptional level by at least four trans-acting genes: CIITA, RFXANK, RFX5 and RFXAP. Defects in these regulatory genes cause MHC class II immunodeficiency, which is frequent in North Africa. The aim of this study was to describe the immunological and molecular characteristics of ten unrelated Moroccan patients with MHC class II deficiency. Immunological examinations revealed a lack of expression of MHC class II molecules at the surface of peripheral blood mononuclear cells, low CD4+ T lymphocyte counts and variable serum immunoglobulin (IgG, IgM and IgA) levels. In addition, no MHC class II (HLA DR) expression was observed on lymphoblasts. The molecular analysis identified the same homozygous 752delG26 mutation in the RFXANK genes of all patients. This finding confirms the association between the high frequency of the combined immunodeficiency and the defect in MHC class II expression and provides strong evidence for a founder effect of the 752delG26 mutation in the North African population. These findings should facilitate the establishment of molecular diagnosis and improve genetic counselling for affected Moroccan families.

HLA-A, -B, -DRB1 alleles and haplotypes frequencies in Moroccan patients with leukemia.

Previous studies have demonstrated some significant differences in HLA allele frequencies in leukemic patients and normal subjects. In Moroccan leukemic patients, the frequency of HLA alleles has not already been determined. We have analyzed HLA class I and class II alleles and haplotypes in 62 Moroccan leukemic patients and 98 unrelated normal subjects using PCR-SSO method. Significant positive association with the disease, in patients compared to controls, was found for three alleles: HLA-B*44 (12.7% vs 6.6%; p = 0.02), HLA-DRB1*13 (11.8% vs 9.79%; p = 0.04) and HLA-DRB*01 (4.5% vs 10.7%; p = 0.05). Regarding haplotypes analysis, no significant association was found between patients and control groups. It is suggested that HLA-B*44 and HLA-DRB1*13 alleles may play a presumptive predisposing factor while the HLA-DRB*01 allele could be a protective genetic factor against leukemia.