Association between antibody response against cytomegalovirus strain-specific glycoprotein H epitopes and HLA-DR

SARS-CoV-2: An immunogenetics call to arms

Susceptibility to viral infection, development of immunity, response to treatment and patient clinical outcomes are all under the control of heritable factors in the host. In the context of the current SARS-Cov-2 pandemic, this review considers existing immunogenetic knowledge of virus-immune system interactions. A major focus is to highlight areas in which work is required in order to improve understanding of antiviral immune responses and to move towards improved patient management.

A role for human leucocyte antigens in the susceptibility to SARS-Cov-2 infection observed in transplant patients

We analysed data from 80 patients who tested positive for SARS‐CoV‐2 RNA who had previously been HLA typed to support transplantation. Data were combined from two adjacent centres in Manchester and Leeds to achieve a sufficient number for early analysis. HLA frequencies observed were compared against two control populations: first, against published frequencies in a UK deceased donor population (n = 10,000) representing the target population of the virus, and second, using a cohort of individuals from the combined transplant waiting lists of both centres (n = 308), representing a comparator group of unaffected individuals of the same demographic. We report a significant HLA association with HLA‐ DQB1*06 (53% vs. 36%; p < .012; OR 1.96; 95% CI 1.94–3.22) and infection. A bias towards an increased representation of HLA‐A*26, HLA‐DRB1*15, HLA‐DRB1*10 and DRB1*11 was also noted but these were either only significant using the UK donor controls, or did not remain significant after correction for multiple tests. Likewise, HLA‐A*02, HLA‐B*44 and HLA‐C*05 may exert a protective effect, but these associations did not remain significant after correction for multiple tests. This is relevant information for the clinical management of patients in the setting of the current SARS‐CoV‐2 pandemic and potentially in risk‐assessing staff interactions with infected patients.

Reinfection of cytomegalovirus in renal transplantation

Cytomegalovirus (CMV) is the most important pathogen affecting the outcome of renal transplantation. Reinfection of CMV can occur in CMV-seropositive donors and CMV seropositive recipients (D+/R+) settings because the protection against CMV conferred by preexisting immunity is limited due to its strain-dependent immune responses. To analyze the influence of CMV reinfection in renal transplantation, ELISA using fusion proteins encompassing epitope of glycoprotein H(gH) from both AD169 and Towne strains was employed before transplantation. The CMV-gH seropositive rate increased with increases in age and the rate of samples which contained antibodies against both AD169 and Towne were significantly high in the age of 50 years or over. Antibodies from HLA-DR10 and DR11 were associated with a significantly lower response rate against CMV-gH. In renal transplantation, the high degrees of antigenemia and high incidences of CMV disease are more prevalent in the CMV gH antibody-mismatched group in D+/R+ setting. The nucleotide sequence of the region of the gH epitope in the CMV-DNA extracted from the transplant recipients who showed high degree of antigenemia revealed the CMV reinfection from the donors. As a CMV indirect effect, the incidence of acute rejection in the mismatched gH antibody group was higher than that observed in the matched and D+/R- groups. The adverse events were more likely to occur in cases of D+/R+ renal transplantation with mismatched strain-specific antibodies which would indicates the risk of CMV reinfection after transplantation.

Human cytomegalovirus: an enormous variety of strains and their possible clinical significance in the human host

Human cytomegalovirus (HCMV) does not exist as one defined virus genotype, but as a variety of different strains. Several studies have investigated the significance of specific viral genotypes for the clinical course of HCMV infection. Upon reinfection, patients may acquire additional HCMV strains, and infections with a mixture of HCMV strains appear to be quite common. The analysis of such mixed infections has become increasingly important, not only for investigating the clinical implications of mixed-genotype infections, but also for understanding the pathogenesis of subsequent reinfections with HCMV strains, and this is also of importance for HCMV vaccine development. This article summarizes the clinical implications of infection with individual HCMV genotypes and focuses on infection with mixed populations of HCMV strains.