Different T cell related immunological profiles in COVID-19 patients compared to healthy controls

Abstract

In various pathological conditions, cellular immunity plays an important role in immune responses. Among immune cells, T lymphocytes pdomote cellular and humoral responses as well as innate immunity. Therefore, careful investigation of these cells has a significant impact on accurate knowledge in COVID-19 disease pathogenesis. In current research, the frequency and function of various T lymphocytes involved in immune responses examined in SARS‐CoV-2 patients with various disease severity compared to normal subjects. In order to make an accurate comparison among patients with various disease severity, this study was performed on asymptomatic recovered cases (n=20), ICU hospitalized patients (n=30), non-ICU hospitalized patients (n=30), and normal subjects (n=20). To precisely evaluate T cells activity following purification, their cytokine secretion activity was examined. Similarly, immediately after purification of Treg cells, their inhibitory activity on T cells was investigated. The results showed that COVID-19 patients with severe disease (ICU hospitalized patients) not only had a remarkable increase in Th1 and Th17 but also a considerable decrease in Th2 and Treg cells. More importantly, as the IL-17 and IFN-γ secretion was sharply increased in severe disease, the secretion of IL-10 and IL-4 was decreased. Furthermore, the inhibitory activity of Treg cells was reduced in severe disease patients in comparison to other groups. In severe COVID-19 disease, current findings indicate when the inflammatory arm of cellular immunity is significantly increased, a considerable reduction in anti-inflammatory and regulatory arm occurred.

An Early Th1 Response Is a Key Factor for a Favorable COVID-19 Evolution

“…A work conducted by Salehi Khesht et al that studied the responses to SARS-CoV-2 with different immunological profiles of T-cells found a positive correlation between the severity of the disease and the Th1 response [57], which could contradict our results. However, Salehi Khesht et al did not carry out a phenotypic study of the lymphocytic population and their study also did not indicate at what point in time of the infection the immune profiles were evaluated (acute or convalescent), so it is not possible to assess whether they mediated a rapid action against the infection or if it occurred.…”

Imbalanced Immune Response of T-Cell and B-Cell Subsets in Patients with Moderate and Severe COVID-19

“…Our study highlights the importance of a Th17-like decrease associated with COVID-19 severity. In contrast with previous studies that identified high levels of Th17 cells in the peripheral blood of patients infected with SARS-CoV-2 [ 4 , 55 , 56 ], our data revealed that the frequency of Th17-like cells in patients with severe COVID-19 was significantly lower than that in the HD ( Figure 5 ). In agreement with our data, De Biasi et al showed that patients with COVID-19 displayed a lower level of Th17 cells with CCR6+CD4+CD3+ and CCR6+CD161+CD4+CD3+ phenotypes [ 38 ], and Gutiérrez-Bautista J. et al demonstrated a persistently low frequency of markers associated with Th1, Th17, and Th1/Th17 memory-effector T cells compared to healthy donors [ 39 ].…”

Potential Immune Indicators for Predicting the Prognosis of COVID-19 and Trauma: Similarities and Disparities

“…Moreover, new findings confirm that high activation of Th17 cells and high signaling of IL-17 are significantly associated with severe COVID-19 (231,246). A recent study showed exhausted T cell profiles are associated with increased Th17 responses in COVID-19 patients with pneumonia (247). It has been reported that Th17 cells increase during the period 2 to 3 weeks post-symptom onset can predict a poor prognosis for COVID-19 complications.…”