Dr. Evelien Bunnik, lead author of the publication, explains that her team’s results indicate that differences in the quality of the immune response depending on the severity of the course COVID-19. It is primarily about memory cell level B (B lymphocytes) that respond to the SARS-CoV-2 virus spike protein.
For the purposes of the study, scientists analyzed blood samples of covid patients one month and five months after the onset of disease symptoms. They noticed that after one month, a significant proportion of the spike protein-specific B cells were active in all test subjects, but samples from convalescents less severely contaminated showed greater expression of markers associated with persistent memory in B cells compared to those who have experienced a more severe course of COVID-19. These markers were the proteins T-bet and FcRL5.
The authors then noted that five months after the infection, T-bet-positive B cells specific for the spike protein almost disappeared from the patients’ blood samplesbut again with some differences with the course of the disease: a more dysfunctional B cell response was observed after severe COVID-19 cases.
Lighter cases defined as undemanding supplemental oxygen administration or the use of invasive ventilation, while those in which the patient required invasive ventilation mechanical or extracorporeal membrane oxygenation (ECMO).
“Based on the results obtained, we can say that there are subtle differences in the B-cell response after mild and severe COVID-19. This suggests that the immune response elicited in mild COVID-19 is of slightly higher quality than that elicited in severe disease. This has an effect on long-term immunity, that is, protection against re-infection with SARS-CoV-2, and the severity of future infection “- conclude the authors of the study.