An increase in NK like T cells (NKT; CD3+CD56+) in patients with COVID-19
Although CD3 positivity is accepted as a marker of adaptive T cells, CD3+CD56+ T cells represent a heterogeneous group of innate cells with their expression of restricted range of T cell receptor (TCR) that play roles in the immune response to tumors and pathogens(19, 20). In our study, the percentage of CD3+CD56+ population was found to be high in COVID-19 patients compared to controls (6.7%±4.3 vs 1.9%±2; p<0.01, Figure 6) No difference was found among patients.
Interestingly, we found that CD25 expression of T cells was very low (CD25 <15% on T cells) in all COVID-19 patients (data not shown).