Major histocompatibility complex (MHC) molecules, also called human leukocyte antigens (HLA), are the product of a set of genes responsible for lymphocytes rejecting transplanted tissues and detecting foreign elements. These molecules also participate in the induction of the specific immune response, through the presentation of the antigen to T lymphocytes.

Within the characteristics of the MHC, it is established that it can have a Polymorphism, which indicates that within a population there are multiple alternative forms of a gene, therefore, the encoded proteins are also different between individuals of the same species. Among the alternative forms, there is HLA-B, whose function is to be Ag (TCR receptor) presenters, identify the own from the strange, and fight to eliminate the strange.

In the article, ARE THERE GENETIC VARIANTS THAT CAN MODIFY THE COURSE OF THE COVID-19 PANDEMIC ?, it is stated that The major histocompatibility complex contains numerous genetic variants and various studies showed that several polymorphisms correlated with susceptibility to SARS-Cov infection and MERS-CoV. An affinity assay study between HLA class I components and the SARS-CoV2 proteome postulates that carrying the HLA-B * 46:01 allele could confer vulnerability to COVID-19, while those with HLA-B * 15:03 could have protection by cross-immunity based on T10 cells .

What do you believe or understand is the variation of the allele, which is causing this effect in people who contract COVID and why? Remember that the function of HLA-B remains the same, but because there are variations, it can perform its function better against a pathogen or not.

Article reference: https://www.medicinabuenosaires.com/indices-de-2020/volumen-80-ano-2020-s-3-indice/variantes/