Were you one of the, what felt like fairly few, people who never got COVID-19 when it seemed like everyone else did? Well, maybe you did and you were asymptomatic with COVID-19. I remember when my whole family was sick with this virus, except for me. I always thought it was just luck, and you might have as well, but what if certain gene mutations can prevent the symptoms of this virus.
In a study done by the National Institute of Health, researchers looked into the genetic variations and how they affected T cells in the immune system. The focus of the study was the human leukocyte antigen complex (HLA). The proteins of these genes prevented people from people feeling symptoms of COVID-19. The proteins of HLA helped the immune system react to the SARS-CoV-2 virus by recognizing the infected cells by presenting pieces of pathogens to the T cells.
At the University of California, San Francisco, researchers studied unvaccinated bone marrow donated from The National Marrow Donor Program/Be The Match. Out of 1,428 donors, 136 were asymptomatic for two weeks before and after testing positive COVID-19. The HLA variant, HLA-B*15:01, had a strong association with the asymptomatic donors. The team, along with researchers from La Trobe University in Australia, studied T-cell memory. They found that the T cells in people who had the HLA-B15 gene, and were never exposed to the COVID-19 virus, responded to the NQK-Q8 peptide in the virus and were able to have a faster immune response. Therefore, people who contain the HLA-B15 gene are prone to being asymptomatic to COVID.
In AP Biology we learned about the immune system’s response to viruses, like SARS-CoV-2. We learned that T-cells and Helper T Cells are part of cell-mediated immunity and are crucial for recognizing antigens and releasing cytokines to trigger immune responses. Then, B and T cells create antibodies and cytotoxic cells to kill off the virus. Memory B and T cells are also formed in order to generate a faster immune response if the body is exposed to the same virus again. Therefore, the immune response stimulated when a person contains the HLA-B15 gene is similar to one where the body uses memory cells to fight an infection.
So, have you never caught COVID-19, or are you one of the lucky people to contain the HLA-B15 gene?
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