Serological testing is everywhere offered as the important tool for control of development of a pandemic of COVID-19. It plays a key role in disease severity assessment, definition of potential donors of therapeutic immune plasm and allows to track development of collective immunity. As well as at other system viral infections, practically at all patients with symptoms within several weeks after emergence of symptoms of a disease IgM and IgG of an antibody are developed. And though IgM usually precedes IgG, at some patients simultaneous increase in level of both antibodies is observed while the intensity of the answer considerably varies.
At the same time, the majority of the published data on COVID-19 was obtained from the hospitalized patients. Not numerous data demonstrate that easy or asymptomatic disease can cause significantly lower IgG-answer. If this assumption is confirmed, then this feature will be of great importance for assessment of population researches and identification of donors of rekonvalestsentny plasma. On the data which are available at the moment, the IgG level correlated with a caption of neutralized antibodies at insignificant number of patients that says that not all serological tests are equivalent in terms of a protektivnost or ability to be a donor of protective antibodys.
The urgent need of urgent granting research materials on SARS-CoV-2 led to emergence of articles with contradictory data on the humoral answer of an organism owner to a virus. Considerable communication between disease severity and the humoral answer was found in some works, and in others — no. Insufficiency of the data which are available today interfered with full clarification of dynamics of development of the humoral answer after infection and to the reliable statistical analysis of differences between clinical groups.
Exact understanding of quantitative parameters of the humoral answer to SARS-CoV-2 will be important both for a health care system, and for therapy. In the USA was the research in which investigated the humoral answer is executed and compared antiserum capacities at patients to a heavy and not heavy current of COVID-19, using clinically approved high-performance quantitative test for IgM and IgG.
In primary group analysis samples of residual serum or a blood plasma from daily clinical laboratory trials were used. All patients had positive takes on SARS-CoV-2 in polymerase chain reaction in real time (RT-PTsR) at capture of smears from a nasopharynx. Clinical data were taken from electronic medical records and included the demographic information, the basic associated diseases reported by the patient, date of emergence of symptoms, disease severity indicators. The analysis of time intervals in 3 weeks and more from the moment of emergence of symptoms, included additional collection of samples of blood serum of the patients who underwent screening on plasma donorship. Donors of plasma were selected according to medical records and through the addresses to the public.
Antibodies to SARS-CoV-2 (IgM and IgG) measured by means of the automated system of the immunoanalysis. In a research of a series of samples were estimated from the moment of conducting RT-PTsR-testirovaniya to an extract from a hospital. Dynamics and amplitude of the humoral answer differed between individuals, but the peak IgM and IgG levels were closely connected with disease severity.
In researches with participation of the people infected with SARS-CoV and MERS are suggested that antiserum capacities decrease over time, but are found more than in a year after hospitalization. Still too early to claim whether IgG credits to SARS-CoV-2 will remain, especially in mild cases with the low level of antibodies. In what degree the strong humoral answer to SARS-CoV-2 leads to neutralization of a virus or contributes to the development of pathology at a serious illness of COVID-19, it is still unknown. Antiserum capacities usually correlate with a protektivnost and neutralization of a virus, but in rare instances antibodies can promote progressing of a disease that leads to the phenomenon known as antitelozavisimy strengthening of an infection. For SARS-CoV, it was shown that at the same time absorption of a virus macrophages increases, leading to the raised products of inflammatory cytokines and acute injury of lungs. Higher antiserum capacities to SARS-CoV-2 in hard cases as it is possible to assume proceeding from our research, can start the similar mechanism for COVID-19.
Additional researches for characteristic of an avidnost and neutralized ability of antibodies to SARS-CoV-2 and also for definition of both the positive, and potentially pathological consequences connected with the level of the humoral answer are necessary.