American scientists around Professor Janko Nikolich-Zugich of the University of Arizona in Tucson and other experts in the field of virology are currently trying to understand why especially older people die of the lung disease COVID-19. According to this, there is not only a certain reaction of the body to the corona virus SARS-CoV-2 but also a series of specific processes in the body. A weakening of the immune response, especially in older people, is called immune senescence, which is described as the „dusk of the immune system“ in old age. Various parts of the immune system react with sometimes excessive reactions against unwanted pathogenic germs such as corona viruses. There are an innate unspecific immune response and an adaptive specific immune defence. Both try to render the intruder harmless. The former defence reacts within a very short time with granulocytes, macrophages and natural killer cells, but is unspecific. The more precise and not so fast starting adaptive immune system consists of T-lymphocytes and B-lymphocytes. The T-lymphocytes recognize and fight foreign antigens. They are produced in the bone marrow and mature in the thymus. However, so-called naive T-cells are formed, which have not yet had contact with the intruder. However, this number of naive T-cells decreases rapidly with age, in contrast to T-memory cells, which remain constant in number and enable a rapid reaction after a renewed confrontation with a germ. However, the communication between the two cells is also disturbed with increasing age, which means that the T-cells‘ attack no longer functions properly, according to a possible explanation provided by the scientists in the online news portal „Stat“. The B-lymphocytes, which become plasma cells after contact with the antigen, for example, coronavirus, produce antibodies, but this production also decreases with age. But there are also discrepancies between the unspecific and the specific series of defence, with increased pro-inflammatory cytokines being released in response, which leads to a worsening of the condition of cornavirus patients and then possibly to death because the age-related overproduction of such messenger substances that cause inflammation can get out of control. However, this overproduction of cytokines is still in the early stages of research and needs to be analysed in greater detail. However, it is already clear that the overproduction and its extent also depends on the age and sex of the patients. For example, older and male patients show a stronger reaction of their innate immune defence, but also higher activity of proinflammatory processes than women and younger people. This explains the correlation and the fact that men in particular, at 62 percent, are among the fatalities in the COVID 19 pandemic. According to the RKI, 86 percent of older people over 70 years of age also died of lung disease, while only 16 percent were younger than 70 years of age.
