Association of HLA and Mutated CCR5 With the Clinical Course of the Disease in Subjects With mild / moderate disease following COVID-19 infection

Abstract

COVID-19, the pandemic infection caused by SARS-CoV-2, may take highly variable clinical courses, ranging from symptom-free and pauci-symptomatic to fatal disease. The goal of the current study was to assess the association of COVID-19 clinical courses controlled by patients’ adaptive immune responses without progression to severe disease with patients’ Human Leukocyte Antigen (HLA) genetics, the presence or absence of near-loss-of-function delta 32 deletion mutant of C-C chemokine receptor type 5 (CCR5) and AB0 blood group antigens. We further analyzed the association of these immunogenetic background characteristics with patients’ humoral antiviral immune response patterns, assessed longitudinally. The study enrolled 157 convalescent adult patients followed up for up to 250 days. Univariate HLA analyses identified putatively protective HLA alleles (HLA class II DRB1*01:01 and HLA class I B*35:01, with a trend for DRB1*03:01) associated with reduced durations of disease and decreased (rather than increased) total anti-S IgG levels providing virus neutralizing capacity comparable to non-carriers. Conversely, analyses also identified HLA alleles (HLA class II DQB1*03:2 und HLA class I B*15:01) not associated with such benefit in the patient cohort of this study. Hierarchical testing by Cox regression analyses confirmed the significance of the protective effect of the HLA alleles identified (when assessed in composite) in terms of disease duration, whereas AB0 blood group antigen heterozygosity was found to be significantly associated with disease severity (rather than duration) in our cohort. A seeming association of a heterozygous CCR5 delta 32 mutation with prolonged disease duration suggested by univariate analyses was not confirmed by hierarchical multivariate testing.In conclusion, the current study shows that the presence of certain "protective" HLA alleles is of even stronger association with reduced duration of mild and moderate COVID-19 than age or any other potential risk factor assessed. Prospective studies in larger patient populations assessing the impact of HLA genetics on the capacity of mounting protective vaccination responses may be warranted.