Correlation of HLA-DP/DQ polymorphisms with transplant etiologies and prognosis in liver transplant recipients

Relevance Between COVID-19 and Host Genetics of Immune Response

The outbreak of coronavirus disease 2019 (COVID-19) was caused by the newly emerged corona virus (2019-nCoV alias SARS-CoV-2) that resembles the severe acute respiratory syndrome virus (SARS-CoV). SARS-CoV-2, which was first identified in Wuhan (China) has spread globally, resulting in a high mortality worldwide reaching ~4 million deaths to date. As of first week of July 2021, ~181 million cases of COVID-19 have been reported. SARS-CoV-2 infection is mediated by the binding of virus spike protein to Angiotensin Converting Enzyme 2 (ACE2). ACE2 is expressed on many human tissues; however, the major entry point is probably pneumocytes, which are responsible for synthesis of alveolar surfactant in lungs. Viral infection of pneumocytes impairs immune responses and leads to, apart from severe hypoxia resulting from gas exchange, diseases with serious complications. During viral infection, gene products (e.g. ACE2) that mediate viral entry, antigen presentation, and cellular immunity are of crucial importance. Human leukocyte antigens (HLA) I and II present antigens to the CD8⁺ and CD4⁺ T lymphocytes, which are crucial for immune defence against pathogens including viruses. HLA gene variants affect the recognition and presentation of viral antigenic peptides to T-cells, and cytokine secretion. Additionally, endoplasmic reticulum aminopeptidases (ERAP) trim antigenic precursor peptides to fit into the binding groove of MHC class I molecules. Polymorphisms in ERAP genes leading to aberrations in ERAP’s can alter antigen presentation by HLA class I molecules resulting in aberrant T-cell responses, which may affect susceptibility to infection and/or activation of immune response. Polymorphisms from these genes are associated, in global genetic association studies, with various phenotype traits/disorders many of which are related to the pathogenesis and progression of COVID-19; polymorphisms from various genes are annotated in genotype-tissue expression data as regulating the expression of ACE2, HLA’s and ERAP’s. We review such polymorphisms and illustrate variations in their allele frequencies in global populations. These reported findings highlight the roles of genetic modulators (e.g. genotype changes in ACE2, HLA’s and ERAP’s leading to aberrations in the expressed gene products or genotype changes at other genes regulating the expression levels of these genes) in the pathogenesis of viral infection.

Human leukocyte antigen gene polymorphisms are associated with systemic inflammation in hepatitis B virus-related hepatocellular carcinoma

Background

Systemic inflammation (SI) is associated with tumor progression and overall survival (OS) in patients with hepatocellular carcinoma (HCC). The presence of some single nucleotide polymorphisms (SNPs) in the human leukocyte antigen (HLA) region can influence the prognosis of patients with hepatitis B virus (HBV)-related HCC, although the mechanism remains unknown. This study aimed to analyze the correlations between HLA gene polymorphisms and SI.

Patients and methods

This study included 330 patients with HCC. The clinical parameters were reviewed, and five SNPs, namely rs2647073, rs3997872, rs3077, rs7453920, and rs7768538, were genotyped using the MassARRAY system.

Results

The rs3997872, rs7453920, and rs7768538 genotypes were found to be significantly associated with OS (P<0.05). The rs7453920 genotype was significantly associated with the neutrophil/lymphocyte ratio (NLR; P=0.001), which was used as an SI index with a threshold determined by receiver operating characteristic analysis. An elevated NLR was also an independent predictor of OS according to univariate and multivariate analyses (P<0.001).

Conclusion

Our data show that HLA gene polymorphisms are associated with SI in patients with HBV-related HCC, and the absence of minor allele A (rs7453920) promotes SI and shortens OS.

The relationship between human leukocyte antigen-DP/DQ gene polymorphisms and the outcomes of HCV infection in a Chinese population

Background

Recently, human leukocyte antigen (HLA) class-II gene polymorphisms have been reported to be related to Hepatitis C virus (HCV) infection and chronicity. The objective of this study was to explore the relationship of HLA-DP rs9277535 and HLA-DQ rs7453920 with the outcomes of HCV infection.

Methods

The rs9277535 and rs7453920 were genotyped in 370 subjects with chronic HCV infection, 194 subjects with spontaneous HCV clearance, and 973 subjects with non-HCV infection from the Chinese population using the ABI TaqMan allelic discrimination assay.

Results

Logistic regression analyses showed that the minor allele A of rs7453920 significantly increased the susceptibility of HCV infection in dominant model (adjusted OR = 1.33, 95% CI: 1.04–1.71, P = 0.026) and additive models (adjusted OR = 1.30, 95% CI: 1.06–1.60, P = 0.012). Rs9277535 A allele significantly increased the risk of chronic HCV infection in dominant model (adjusted OR = 1.52, 95% CI: 1.01–2.28, P = 0.046). Haplotype AA showed a higher risk of HCV infection than the most frequent haplotype GG (adjusted OR = 1.37, 95% CI: 1.05–1.78, P = 0.018).

Conclusion

The HLA-DQ rs7453920 and -DP rs9277535 mutations were significantly associated with HCV infection susceptibility and chronicity, respectively.

Electronic supplementary material

The online version of this article (10.1186/s12985-017-0901-7) contains supplementary material, which is available to authorized users.