One in five people who contract the COVID-19 virus don ’t get sick. A gene variant may explain why

SARS-CoV-2 kills some of the people it infects and makes many others miserable. But a fortunate few skate through a bout of COVID-19 without suffering symptoms. One key to avoiding illness, according to a new study, is a version of a particular immune system gene that only some people carry. When individuals with this gene variant are exposed to common coronaviruses that cause colds, the research shows, they gain protection against SARS-CoV-2. “I love this paper,” says immunologist Shane Crotty of the La Jolla Institute for Immunology, who wasn’t connected to the research. The study, he says, provides “the strongest genetic evidence to date” that people who come down with the cold-causing coronaviruses produce immune cells that can fight off SARS-CoV-2. About 20% of people infected with SARS-CoV-2 say they don’t feel ill, but researchers haven’t uncovered why they remain symptom-free. At the top of the list of potential protectors are human leukocyte antigen ( HLA ) genes, which encode proteins that help the body fight off pathogens. If a virus sets up shop in one of our cells, HLA proteins on the cell’s surface display shards of the invader’s proteins, alerting the immune system. T cells—which recognize and “remember” pathogens—then kill the infected cell, short-circuiting the virus’ replication. HLA genes come in thousands of varieties, many of which influence how vigorously people’s immune systems ...
Source: ScienceNOW - Category: Science Source Type: news