Howard Hughes Medical Institute — Medical X Press — 25 June 2020
Women generally mount a more effective immune response against the virus SARS-CoV-2, a new study suggests. The study is the first to delve into sex differences in how the immune system defends itself against the virus, and could help explain why men can fall more severely ill from COVID-19.
A two-part immune response is key. When a viral infection begins, infected cells send out cytokine proteins that summon immune cells to fight. This inflammation can be dangerous if not controlled — in COVID-19, runaway inflammation known as a cytokine storm can cause death. Within days, the second immune layer enlists T and B cells that learn to recognize the enemy and eradicate it.
The team found that female patients had more of the virus-fighting T cells, while men had higher levels of inflammation-promoting cytokines. “This suggests men are stuck in the first layer of the immune response,” said Howard Hughes Medical Institute Investigator Akiko Iwasaki of Yale University. Men whose condition remained stable generated strong T cell responses, not unlike the women’s. However, men lacking a strong T-cell response fared worse — they needed ICU care or ventilators. While men’s T cell levels declined with age, levels remained strong for women into their 90s.