Scientists at Osaka University have identified the reasons why men endure COVID-19 more severely than women. The results of the study are published in the journal Proceedings of the National Academy of Sciences (PNAS).
It is known that when infected with SARS-Cov-2, a person may experience serious disruptions in humoral immunity, which is the synthesis of antibodies in response to the penetration of foreign bodies, in this case viruses. The immune response is regulated and controlled by regulatory T cells (Tregs), which normally suppress the immune response, but in the case of COVID-19, Treg function is often impaired.
The scientists used the method of single cell proteomics using mass cytometry, which allows to identify the molecular features of cells. They found sex differences in Treg, which may explain why men, on average, suffer from more severe symptoms than women. A specific type of Treg called T-follicular regulatory cells (Tfr) is responsible for controlling the production of antibodies. It turned out that in male patients there is a rapid loss of circulating Tfr.
In addition, sex differences were found in the entire network of immune cells responsible for antibody synthesis. Thus, the number of peripheral blood T-helpers, plasma blasts, proliferating and extrafollicular/atypical CD11c+ memory B cells positively correlated with the concentrations of neutralizing antibodies and negatively correlated with the level of cTfr.
An increase in antibody levels with a decrease in regulatory cells in men may indicate that these antibodies target proteins produced by the patient’s own cells, i.e. many of them are autoantibodies. This can lead to severe complications and organ damage.