Scientists have discovered a genetic trait related to white blood cells in 60% of the Japanese population that helps the body better fight Covid-19.
The study, led by the Riken Institute, was published in the British journal Communications Biology in December. It is part of an effort to further understand what causes the number of severe nCoV infections and mortality in Japan to be similar. relatively low.
The study focused on “killer” T cells, which are part of the immune response when a virus enters the body. These cells seek out and destroy infected cells, identifying them through peptide compounds or specific protein fragments from the virus.
The team from the Riken Institute looked at a type of human leukocyte antigen, called HLA-A24. It is located on the surface of cells and helps to stimulate T cells, which play an important role in the human self-defense mechanism.
HLA-A24 occurs in the blood of about 60% of the Japanese population. When a peptide called QYI from nCoV is introduced into the blood of volunteers with this antigen, the killer T cells respond rapidly. Those cells also respond similarly to other coronaviruses, which cause seasonal flu.
The study concluded that in people with Covid-19 who have HLA-A24, T cells in the body remember past infections with the seasonal flu corona virus, thereby creating an effective immune response. HLA-A24 is common in Asians, but is rarer in the West, occurring in about 10-20% of the population of Europe and America.
Shin-ichiro Fujii, the head of the immunotherapy experiment at the Riken Institute, who participated in the study, said: “This can be considered a mysterious factor (the low number of severe cases and deaths in Japan in Japan). )”. The test only checks for specific cells. Scientists need to study more about how the immune system of people with HLA-A24 responds after being infected with nCoV.
The number of Covid-19 cases in Japan in recent days is usually around 100, ie less than one case per million people, the lowest level in developed countries, outside of China. In recent days, Japan has not recorded any deaths.
Meanwhile in South Korea, with vaccination rates similar to Japan, the number of new cases increased to a record. This situation also happened in Singapore and Australia after the government eased travel restrictions.
Thuc Linh (Follow Nikkei)