Association of HLA genotypes, AB0 blood type and chemokine receptor 5 mutant CD195 with the clinical course of COVID-19

Abstract

Background: COVID-19, the pandemic disease caused by infection with 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, AB0 blood group antigens, and the presence or absence of near-loss-of-function delta 32 deletion mutant of the C-C chemokine receptor type 5 (CCR5).

Patient and methods: An exploratory observational study including 157 adult COVID-19 convalescent patients was performed with a median follow-up of 250 days. The impact of different HLA genotypes, AB0 blood group antigens, and the CCR5 mutant CD195 were investigated for their role in the clinical course of COVID-19. In addition, this study addressed levels of severity and morbidity of COVID-19. The association of the immunogenetic background parameters were further related to patients' humoral antiviral immune response patterns by longitudinal observation.

Results: 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). They were associated with reduced durations of disease instead decreased (rather than increased) total anti-S IgG levels. They had a higher virus neutralizing capacity compared to non-carriers. Conversely, analyses also identified HLA alleles (HLA class II DQB1*03:02 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 suggestive association of a heterozygous CCR5 delta 32 mutation status with prolonged disease duration was implied by univariate analyses but could not be confirmed by hierarchical multivariate testing.

Conclusion: The current study shows that the presence of HLA class II DRB1*01:01 and HLA class I B*35:01 is of even stronger association with reduced disease duration in mild and moderate COVID-19 than age or any other potential risk factor assessed. Prospective studies in larger patient populations also including novel SARS-CoV-2 variants will be required to assess the impact of HLA genetics on the capacity of mounting protective vaccination responses in the future.

Keywords: ABO blood group; CCR5; COVID-19; Chemokine receptor; Clinical course; HLA class I genotypes; Neutralizing antibodies; SARS-CoV-2.

Fig. 1

SARS-CoV-2 viral protein-specific antibody levels in plasma drawn up to 250 days following the end of the symptoms from individuals with different disease severity. Disease severity was according to WHO classification (Blue indicates WHO °1, green WHO °2, gold WHO °3). Shown are the results of the first blood draw after including the individual into the study. A S1 protein-specific IgA antibody levels, measured with the Euroimmun assay. Results are expressed as ratio. B S1 protein-specific IgG antibody levels, measured with the Euroimmun assay. Results are expressed as ratio. C Nucleocapsid (N)-specific IgG antibody levels measured with the Euroimmun assay. Results are expressed as ratio. D N-specific Ig antibody levels detected with Elecsys®, Roche. E The SARS-CoV-2 serum neutralization titer, determined by microscopic inspection as the highest serum dilution without virus-induced cytopathic effect. Outliers are presented as circles (more than 1.5 IQR out of the box) or stars (more than 3 IQR out of the box). Day after end of symptoms was divided into quartiles (d20 to d31, d32-d47, d48-d76, > d77, range between d20 to d120)

Fig. 2

SARS-CoV-2 viral protein-specific antibody levels in plasma samples sequentially drawn from infected individuals between day 10 and day 188 following symptom onset. SARS-CoV-2 viral protein-specific antibody levels were determined as described in the legend of Fig. 1

Fig. 3

Significantly lower SARS-CoV-2 viral protein-specific antibody levels and significantly longer disease duration in individuals carrying the CCR5 delta 32 mutation heterozygously with WHO° 1 and WHO° 2a disease following SARS-CoV-2 infection. SARS-CoV-2 viral protein-specific antibody levels were determined as described in the legend of Fig. 1 in 23 individuals carrying the CCR5 delta 32 mutation heterozygously and in 105 individuals carrying the wild type CCR5 gene (A). Disease duration in individuals with WHO° 1 and WHO° 2a disease following SARS-CoV-2 infection is shown in B for 8 heterozygous carriers of the CCR5 delta mutation and 39 non carriers

Fig. 4

Association of HLA-DRB1*03:01, HLA-DRB1*01:01 and/ or HLA-B*35:01 allele expression with shorter COVID19 disease duration in SARS-CoV-2 infected individuals. A The disease duration related to HLA DRB1* 03:01 expression, B The disease duration related to HLA*DBR1*01:01 expression, C Disease duration related to HLA B* 35:01 expression. D The disease duration related to the combination of HLA: DRB1*01:01 and or HLA B* 35:01 expression. (0) indicates the 81 individuals who express neither allele, (1) indicates the 22 individuals who express HLA: DRB1*01:01 (n = 13) or HLA B* 35:01 allele (n = 9), and (2) indicates the 6 individuals expressing both alleles

Fig. 5

Association of “protective” HLA alleles with SARS-CoV-2 viral protein-specific antibody levels. A and E show similar levels of S1-specific IgA antibodies in the individuals who express “protective” HLA alleles and those who do not. B and C show a significantly lower level of S1-specific IgG antibodies and N-specific antibodies in the 15 individuals who express the HLA-B*35:01 allele (green) than in the 94 individuals who do not express (blue). F and G show a significantly lower level of S1-specific IgG antibodies and N-specific antibodies in the 19 individuals who express the HLA-DRB1*01:01 allele (green) than in the 100 individuals who do not express (blue). D and H show no detectable difference in the titer of neutralizing antibodies between individuals who express “protective” HLA alleles and those who do not

Fig. 6

Effect of concomitant infection on the association of AB0 blood group heterozygosity with prolonged disease duration. A shows the disease duration in 43 individuals in whom infection event affected less than 3 individuals. B shows disease duration in 68 individuals in whom the infection event affected at least 3 individuals

Fig. 7

Association of AB0 blood group heterozygosity with development of WHO° 2b and WHO° 3 disease. A logistic regression analysis included as covariates gender, age, multispreading (whether infection event affected at least 3 individuals), ‘‘protective “ HLA alleles (as defined on the Results section), the further class I HLA alleles C2 and HLA-Bw4 (included on this analysis for their binding to distinct killer-cell immunoglobulin-like receptors (KIRs) expressed by natural killer-cells), the heterozygous CCR5 delta 32 mutation and AB0 blood group allele heterozygosity. Odds ratios and their confidence intervals for individuals with COVID 19 WHO° 1 to WHO° 3 are shown

Fig. 8

HLA alleles as most informative prognostic biomarkers of disease duration. A Cox regression analysis included as covariates gender, age, number of ‘‘protective “ HLA alleles, HLA encoded NK-KIR ligand for KIR2DL1/ KIR2DS1 (HLA-C2) and KIR3DL1/KIR3DS1 (HLA-Bw4), heterozygous CCR5 delta 32 mutation, as well as AB0 blood group allele homozygosity. A The results of a Cox regression analysis performed in 81 individuals for whom all the listed information is available. B shows the results of a Cox regression analysis performed in 51 individuals with WHO° 1 and WHO° 2a disease. C The results of a Cox regression analysis performed in 30 individuals with WHO° 2a and WHO° 3 disease. Hazard ratio for disease duration and respective 95% confidence interval is shown for the first step and the last step after backward conditional regression