Some Individuals Have Remained Unaffected by COVID-19, Possibly Due to a Little-Known Genetic Factor

People who have managed to avoid COVID-19 for over four years may owe their immunity to a newly discovered immune response, according to a recent study. Researchers deliberately exposed volunteers to the virus and found that those with the heightened activity of a little-known immune gene called HLA-DQA2 did not sustain an infection after exposure to SARS-CoV-2.

Published in Nature on June 19, the study offers “unprecedented insights into how the immune system responds to the virus and how variations in this response may explain why some people get sick while others do not.”

Study Design and Unexpected Outcomes

The study involved a challenging trial in the UK where 36 young, healthy, unvaccinated individuals were exposed to the virus. Surprisingly, only six participants became ill, allowing researchers to closely examine immune responses in those who remained unaffected.

They discovered that some participants either never tested positive for the virus or quickly suppressed transient infections in their noses, preventing illness. These individuals showed early and robust immune responses in cells like monocytes and MAIT cells, which are critical for detecting and fighting viral threats.

Insights into Immune Responses

Participants who did become ill exhibited delayed interferon responses in their noses compared to healthy participants, suggesting that “swift local immune reactions may prevent the virus from establishing an infection.” Intriguingly, blood samples from those who fell ill showed interferon activity before their nasal cells did, highlighting complex immune dynamics during early infection.

Before exposure, individuals who avoided illness exhibited elevated activity of the HLA-DQA2 gene in specialized immune cells, potentially indicating a protective genetic signature. This finding raises the possibility of predicting susceptibility to infection based on genetic markers like HLA-DQA2.

Genetic Insights and Predictive Potential

While the study’s findings are valuable, subsequent challenge trials have faced difficulties replicating these conditions due to widespread immunity from infection or vaccination. Researchers recognize the unique opportunity this study provided and emphasize the need for broader, more diverse studies to understand varying immune responses across populations and over time. The study underscores the “importance of such research in informing future strategies for managing infectious diseases like COVID-19.”

Read the Original Article on: Science News

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