HLA class I (-A, -B, -C) and class II (-DR, -DQ) polymorphism in the Mauritanian population

Genetic variation of TLR3 gene is associated with the outcome of hepatitis b infection in mauritanian patients: case control study

BACKGROUND

Toll-Like receptors (TLRs) play an important role in the immune response during hepatitis B virus (HBV) infection. In this study, we evaluated the association between two SNP variants (TLR3 rs3775290 and TLR4 rs4986790) and susceptibility to chronic HBV infection in Mauritania.

SUBJECTS AND METHODS

A total of 188 subjects were recruited for this study: 102 chronically infected patients and 86 individuals with spontaneously resolved HBV infection who were considered controls. Targeted PCR products were sequenced using Sanger sequencing.

RESULTS

We found that TLR3 rs3775290 was significantly more frequent in patients with chronic HBV than in the control population (p = 0.03). However, no association was found between the TLR4 rs3775290 polymorphism and chronic infection.

CONCLUSION

Our results suggest that the TLR3 rs3775290 polymorphism may be a risk factor for susceptibility to chronic HBV infection in the Mauritanian population.

Can presence of HLA type I and II alleles be associated with clinical spectrum of CHIKV infection?

Host immune response and virulence factors are key to disease susceptibility. However, there are no known association studies of human leukocyte antigen (HLA) class I and II alleles with chikungunya virus (CHIKV) infection in the Latin American population. Here, we aimed to identify HLA alleles present in patients with CHIKV infection versus healthy controls as well as the allelic association with the clinical spectrum of the disease. We conducted a cross-sectional analysis of a community cohort and included patients aged 18 years and older with serologically confirmed CHIKV infection. HLA typing of HLA-A, HLA-B, and HLA-DRB1 alleles was performed. Two-by-two tables were used to establish associations between allele presence and clinical characteristics. Data from 65 patients with confirmed CHIKV infection were analyzed for HLA typing. CHIKV infection was significantly associated with the presence of HLA-A*68 [p = .005; odds ratio (OR): 8.90; 95% confidence interval (CI): 1.88-42.13], HLA-B*35 (p = .03; OR: 2.01; 95% CI: 1.06-3.86), HLA-DRB*01 (p <.001; OR: 5.70; 95% CI: 1.95-16.59), HLA-DRB1*04 (p <.001; OR: 7.37; 95% CI: 3.33-16.30), and HLA-DRB1*13 (p = .004; OR: 3.75; 95% CI: 1.50-9.39) alleles in patients versus healthy subjects. A statistically significant relationship was found between the presence of a rash on the face or abdomen and the presence of HLA-DRB1*04 (p = .028; OR: 3.2; 95% CI: 1.11-9.15 and p = .007; OR: 4.33; 95% CI: 1.45-12.88, respectively). Our study demonstrated that, in our cohort, HLA type I and type II alleles are associated with CHIKV infection, and an HLA type II allele is associated with dermatological symptoms. Further research is needed to establish a path for future investigation of genes outside the HLA system to improve knowledge of the pathophysiology of CHIKV infection and its host-pathogen interaction.

SARS-CoV-2: Origin, Intermediate Host and Allergenicity Features and Hypotheses

The goal of this study is to investigate the probable intermediate hosts and the allergenicity of the notorious virus SARS-CoV-2 to understand how this virus emerged. The phylogenetic analysis of the virus spike proteins indicates that SARS-CoV-2 falls into various small subclades that include a bat coronavirus RaTG13, suggesting bats as a likely natural origin. Refined alignment of the spike protein in NCBI found several fragments that are specific to SARS-CoV-2 and/or SARS-CoV are specific to Rattus norvegicus and/or Mus musculus, suggesting that rodents are the intermediate reservoir of SARS-CoV-2 and SARS-CoV. To evaluate the allergenicity values, the binding affinities of human leukocyte antigen (HLA) class I or II molecules with the spike proteins were calculated, and the results showed that both SARS-CoV-2 and SARS-CoV are predicted to bind to fourteen HLA class I and II molecules with super-high HLA allele-peptide affinities. The infection rate of individuals who have HLA alleles with very high binding affinities who might become infected and develop into refractory patients if there were no medical or non-medical interventions is about 7.36% and 4.78% of Chinese and Americans, respectively. Extremely high temperature and exceptionally low precipitation, the common climate factors between the outbreak sites of COVID-19 in Wuhan in 2019 and SARS in Guangdong in 2002, might have promoted coronavirus evolution into more virulent forms. Our hypothesis suggests that early immunization with an allergenically-engineered virus, in combination with continued surveillance of meteorological factors and viral mutations, may be one of the most powerful prophylactic modalities to fight this virus.

Mutation profile of glaucoma candidate genes in Mauritanian families with primary congenital glaucoma

Purpose

Intraocular pressure leading to glaucoma is a major cause of childhood blindness in developing countries. In this study, we sought to identify gene variants potentially associated with primary congenital glaucoma (PCG) in the Mauritanian population.

Methods

Using next-generation sequencing (NGS), a panel of PCG candidate genes was screened in a search for DNA mutations in four families with multiple occurrences of PCG.

Results

Targeted exome sequencing analysis revealed predicted pathogenic mutations in four genes: CYP1B1 (c.217_218delTC, p.Ser73Valfs*150), MYOC (878C>A, p.T293K), NTF4 (c.601T>G, p.Cys201Gly), and WDR36 (c.2078A>G, p.Asn693Ser), each carried by a different family.

Conclusions

Genetic variation associated with PCG in this study reflects the ethnic heterogeneity of the Mauritanian population. However, a larger cohort is needed to identify additional families carrying these mutations and confirm their biologic role.