Coronavirus COV-19/SARS-CoV-2 affects women less than men: clinical response to viral infection.

CoV-19/SARS-CoV-2 is a highly pathogenic virus that causes coronavirus-19 disease (COVID-19) an acute respiratory distress syndrome which provokes serious problems for global health. Studies suggest that there are many differences between men and women in the immune response to CoV-19 infection and inflammatory diseases. Women, compared to men, are less susceptible to viral infections based on a different innate immunity, steroid hormones and factors related to sex chromosomes. The presence of two X chromosomes in women emphasize the immune system even if one is inactive. The immune regulatory genes encoded by X chromosome in female gender causes lower viral load levels, and less inflammation than in man, while CD4+ T cells are higher with better immune response. In addition, women generally produce higher levels of antibodies which remain in the circulation longer. The levels of activation of the immune cells are higher in women than in men, and it is correlated with the trigger of TLR7 and the production of IFN. TLR7 is higher in women than in men and its biallelic expression leads to higher immune responses and increases the resistance to viral infections. TLR7 is expressed in innate immune cells which recognizes single strand RNA virus by promoting the production of antibodies against the virus and the generation of pro-inflammatory cytokines including IL-6 and IL-1 family members. Moreover, in women the production of inflammatory IL-6 after viral infection is lower than in males and is often correlated with a better longevity. In addition, on the X chromosome there are loci that code for the genes involved in the regulation of immune cells such as FOXP3, and transcription factor for Treg involved in virus pathogenesis. The X chromosome influences the immune system by acting on many other proteins, including TLR8, CD40L and CXCR3 which can be over-expressed in women, and influence the response to viral infections and vaccinations. However, the biallelic expression of the X-linked genes can promote harmful autoimmune and inflammatory responses. Cardiovascular diseases are more frequent in males and subjects without cardiovascular dysfunctions infected by CoV-19 have a better prognosis, but these effects are still under study. It is hoped that certain drugs, such as CoV-19 receptor blockers, anti-inflammatories (against rheumatic diseases), monoclonal antibodies, anti-IL-1 and anti-IL-6, the remdesevir drug (analogue adenosine, effective against ebola), hydroxychloroquine (for the treatment of malaria) and vaccines, will open up new strategies and new therapeutic ways to combat this terrible virus. Copyright 2020 Biolife Sas. www.biolifesas.org.