Protective HLA alleles against severe COVID-19: HLA-A*68 as an ancestral allele in Mexico

HLA is a polymorphic antigen presenter which has provided valuable information on the susceptibility of populations to viruses. Therefore, the study of HLA can reveal specific susceptibility or resistance alleles to severe COVID-19 in an ethnically dependent manner. This pilot study investigated HLA alleles associated with COVID19 severity in Tapachula, Chiapas, Mexico. A total of 146 Mexican Mestizos were typed for HLA class I and II using PCR-SSP. The patients were classified according to the outcome (death or improvement) and the infection's severity (mild or severe). In addition, a group of exposed uninfected individuals was included. HLA-A*68 was found to be a protective allele against the severe infection and fatal outcome; pC = 0.03, OR = 0.4, 95% CI =0.20-0.86, and pC =0.009, OR = 0.3, 95% CI =0.13-0.71 respectively. HLA-DRB1*03 also appears to be a protective factor against fatal outcome pC = 0.009, OR = 0.1, 95%IC = 0.01-0.66; however, the low frequency of this allele in the studied population limits the statistical power. The severity and fatal outcome of COVID-19 patients in Tapachula, Chiapas depend more on the lack of resistance than susceptibility HLA alleles.

Automated summary

This study investigated the association between HLA alleles and the severity of COVID-19 in Tapachula, Chiapas, Mexico. The results showed that HLA-A*68 and HLA-DRB1*03 may have a protective effect against severe infection and fatal outcome. However, the low frequency of HLA-DRB1*03 in the population limited the statistical power. The study suggests that the severity and fatal outcome of COVID-19 patients in this region depend more on the lack of resistance HLA alleles.