5 research outputs found
Characterization of memory T cell subsets and common Îłâchain cytokines in convalescent COVID-19 individuals
T cells are thought to be an important correlates of protection against SARSâCoV2 infection. However, the composition of T cell subsets in convalescent individuals of SARSâCoV2 infection has not been well studied. The authors determined the lymphocyte absolute counts, the frequency of memory T cell subsets, and the plasma levels of common Îłâchain in 7 groups of COVIDâ19 individuals, based on days since RTâPCR confirmation of SARSâCoVâ2 infection. The data show that both absolute counts and frequencies of lymphocytes as well as, the frequencies of CD4(+) central and effector memory cells increased, and the frequencies of CD4(+) naĂŻve T cells, transitional memory, stem cell memory T cells, and regulatory cells decreased from Days 15â30 to Days 61â90 and plateaued thereafter. In addition, the frequencies of CD8(+) central memory, effector, and terminal effector memory T cells increased, and the frequencies of CD8(+) naĂŻve cells, transitional memory, and stem cell memory T cells decreased from Days 15â30 to Days 61â90 and plateaued thereafter. The plasma levels of ILâ2, ILâ7, ILâ15, and ILâ21âcommon Îłc cytokines started decreasing from Days 15â30 till Days 151â180. Severe COVIDâ19 patients exhibit decreased levels of lymphocyte counts and frequencies, higher frequencies of naĂŻve cells, regulatory T cells, lower frequencies of central memory, effector memory, and stem cell memory, and elevated plasma levels of ILâ2, ILâ7, ILâ15, and ILâ21. Finally, there was a significant correlation between memory T cell subsets and common Îłc cytokines. Thus, the study provides evidence of alterations in lymphocyte counts, memory T cell subset frequencies, and common Îłâchain cytokines in convalescent COVIDâ19 individuals
Dynamic alterations in monocyte numbers, subset frequencies and activation markers in acute and convalescent COVID-19 individuals
Monocytes are thought to play an important role in host defence and pathogenesis of COVID-19. However, a comprehensive examination of monocyte numbers and function has not been performed longitudinally in acute and convalescent COVID-19. We examined the absolute counts of monocytes, the frequency of monocyte subsets, the plasma levels of monocyte activation markers using flowcytometry and ELISA in seven groups of COVID-19 individuals, classified based on days since RT-PCR confirmation of SARS-CoV2 infection. Our data shows that the absolute counts of total monocytes and the frequencies of intermediate and non-classical monocytes increases from Days 15â30 to Days 61â90 and plateau thereafter. In contrast, the frequency of classical monocytes decreases from Days 15â30 till Days 121â150. The plasma levels of sCD14, CRP, sCD163 and sTissue Factor (sTF)âall decrease from Days 15â30 till Days 151â180. COVID-19 patients with severe disease exhibit higher levels of monocyte counts and higher frequencies of classical monocytes and lower frequencies of intermediate and non-classical monocytes and elevated plasma levels of sCD14, CRP, sCD163 and sTF in comparison with mild disease. Thus, our study provides evidence of dynamic alterations in monocyte counts, subset frequencies and activation status in acute and convalescent COVID-19 individuals