Hypothetical COVID-19 protection mechanism: hints from centenarians.

The risk of serious complications and the fatality rate due to COVID-19 pandemic have proven particularly higher in older persons, putting a further strain in healthcare system as we dramatically observed.COVID-19 is not exclusively gerophile (géro "old" and philia "love") as young people can be infected, even if older people experience more severe symptoms and mortality due to their greater frailty. Indeed, frailty could complicate the course of COVID-19, much more than the number of years lived. As demonstration, there are centenarians showing remarkable capacity to recover after coronavirus infection.We hypothesize that centenarian's portfolio could help in identifying protective biological mechanisms underlying the coronavirus infection.The human leukocyte antigen (HLA) is one of the major genetic regions associated with human longevity, due to its central role in the development of adaptive immune response and modulation of the individual's response to life threatening diseases. The HLA locus seems to be crucial in influencing susceptibility and severity of COVID-19.In this hypothesis, we assume that the biological process in which HLA are involved may explain some aspects of coronavirus infection in centenarians, although we cannot rule out other biological mechanisms that these extraordinary persons are able to adopt to cope with the infection.