Dynamics of immune system parameters in development of SARS-CoV-2-specific immunity in a patient with common variable immune deficiency

With the accumulation of data on the evolving SARS-CoV-2 infection pandemic, it became clear that the risk factors for severe course of COVID-19 among the patients with primary immunodeficiency include disorders associated with dysregulation of the immune response. In this regard, it is of interest to identify possible predictors of the pronounced inflammatory reaction upon infection with coronavirus in the patients with general variable immune insufficiency. For this purpose, the dynamics of immune system parameters was studied in a patient with CVID who underwent a severe clinical variant of COVID-19, as an example of clinical case. We present patient K., 49 years old, with CVID diagnosis verified at the age of 35 years who received regular replacement therapy with IVIG. He suffered from COVID-19 in severe form, received anti-cytokine therapy and an additional course of IVIG during the treatment. He was discharged in satisfactory condition. The quantitative and functional parameters of the T and B lineages of immune system were evaluated by flow cytofluorimetry during routine examinations before the infection and three months after the discharge from the hospital after COVID-19. It has been shown that, before the disease, there were changes in the parameters of B cells characteristic of CVID manifesting as a decrease in switched-memory B cells and plasmoblasts. Alterations in the T cell subsets were also revealed, as redistribution of the subpopulation composition towards T effectors with an increased cytolytic potential of these cells and a weakening of T cell suppression, due to decreased Treg in peripheral blood. After undergoing COVID-19, the patient developed specific IgM and IgG antibodies. The development of immune response was accompanied by an increase in the number of un-switched and switched memory B cells. At the same time, we have registered an increase in memory T cells ready for the proliferative response of T helper cells and Treg cells. The initial pro-inflammatory pattern of the T cell lineage system in our patient with CVID is explained by the implementation of the compensatory capabilities of the immune system, thus leading to activation of the cytolytic effects of cellular compartment in adaptive immune response, along with attenuation of the humoral component. Moreover, it is likely that these changes contributed to the clinical course of COVID-19 in this clinical case. Development of a specific humoral response to SARS-CoV-2 in a patient with CVID after a COVID-19 infection is accompanied by an increased proportion of memory B cells, coordinated dynamics of T cell suppression and activation parameters.