Phenotyping of lymphocyte subsets, Th-1/Th-2 cytokines and other parameters in high-risk contacts of SARS-CoV-2

Abstract

Background: The information on the pathophysiology of infection in high-risk contacts of SARS-CoV-2 is limited. Aims: The aim of the present study was to assess the various factors and their elucidation in the protection of SARS- CoV-2 infection in high-risk contacts. Settings and Design: Cross-sectional descriptive clinical study. Materials and Methods: A total of 136 subjects were recruited in the present study including 100 high-risk subjects and 36 control subjects. Out of 100 high-risk subjects, 44 subjects were found positive for SARS-CoV-2 RNA. Further, absolute blood counts of total T-cells (CD3+), T-helper cells (CD4+), T-cytotoxic cells (CD8+), B lymphocytes (CD19+) Natural Killer (NK) Cells (CD16+, CD56+), cytokines, and other parameters were measured in the samples of study subjects. Statistical Analysis Used: The continuous variables were analyzed by unpaired 't' test, analysis of variance and 'Tukey test' for multiple comparisons. Results: A significant reduction of total leukocyte counts and absolute lymphocyte count was found in the acute SARS-CoV-2 positive group as compared to control group (<0.05). Interestingly, IL-4 level was significantly elevated in SARS-CoV-2 negative high-risk subjects as compared to control and acute SARS-CoV-2 positive group (p < 0.05). A significant decrease of T-cytotoxic, B-cells, and NK cells were found in acute SARS-CoV-2 positive subjects as compared to control groups. Conclusion: The findings of this study may augment our knowledge about the pathogenesis of SARS-CoV-2 infection that could help in making future strategies to control its infection.

Keywords

• cellular immunity
• covid-19 disease
• cytokines
• flow cytometry
• lymphocytes