Sequential Shifting in T-helper and T-cytotoxic Subset Cell Population in Mild and Severe COVID-19 Patients Infected With Variant B.1.61

Aim: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) modulates antiviral immunity via T cells, but whether these cells are active or abundant in coronavirus disease 2019 (COVID-19) patients is unknown. The present study aimed to investigate the temporal shifting T-cell population and their subsets, T-Helper (Th) cell (CD4) T-Cytotoxic (Tc) (CD8) COVID-19 patients. Method: Thirty confirmed (nasal swab reverse transcription-polymerase chain reaction (RT-PCR) confirmed) were enrolled. On basis of oxygen saturation (SpO2) levels, stratified into two categories: (i) mild (n=11) having fever SpO2 level >95%, (ii) severe (n=19) on ventilator, intensive care unit (ICU) as per Indian Council Medical Research (ICMR) guidelines. age-sex-matched controls without infectious diseases unrelated also enrolled study. Patients with inflammatory comorbidities that compromise excluded from Immunophenotyping flow cytometry assay was used evaluate viability, Th, Tc day 1 (at admission) 4 (decreasing infection load) second wave (variant: B.1.61). Categorical variables expressed frequency percentage p-values calculated by Chi-square test. All represented median Q1 (25 percentile) Q3 (75 percentile). Mann-Whitney test compare groups. Δ mean differences using Paired samples t-test. statistically significant taken p<0.05. Results: Hemoglobin, total leukocyte count (TLC), lymphocytes, monocytes, eosinophils significantly reduced (p<0.05). A decrease CD4 CD8 vs. (CD4, 49; CD8, 40.12; p>0.05) seen. Th-EM (effector memory)-Tim-3 (T-cell immunoglobulin domain mucin 3)+ higher (p=0.002) however, Tc-EMRA memory re-expressing)-Tim-3+, Tc-Naive-Tim-3+, Tc-EM-PD1+ Tc-CM (central memory)-Tim-3+ (p<0.05) than controls. Similarly, patients, Th-EMRA-Tim-3+, Th-Naive-PD1+, Th-EM-PD1+, Th-EM-Tim 3+ Th-CM-Tim-3+ showed a reduction Tc-EMRA-Tim-3+, Tc-EM-PD1+, Tc-CM-Tim-3+ similar results. In group, decreased T-cells (p=0.001), Th-EMRA-Tim-3+ (p=0.024), Th-Navie-Tim-3+ (p=0.005), increased Tc-Naive-Tim3+ Tc-EM-Tim-3+ (p=0.031), (p=0.08) observed. increase Th-Naive-Tim3+ (day 4-day 1; δ43, p=0.019), Th-EM-Tim3+ (δ 16.24, p=0.033), Th-CM-Tim3+ 13.57, p=0.041). Conclusion: populations subset help differentiate Monitoring especially changes, has important implications for diagnosing treating being critically ill.