T cell exhaustion plays a crucial role in reducing the antiviral activity of lymphocytes.
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LAG-3, TIM-3, TIGIT, and PD-1 as co-inhibitory receptors involved in the T cell exhaustion in Covid-19 patients.
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T-bet and Eomes as transcription factors involved in the T cell exhaustion in Covid-19 patients.
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Severe Covid-19 patients represented a higher level of the co-inhibitory receptor gene expressions compared to mild patients.
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Severe Covid-19 patients represented a higher level of the transcription factor gene expressions compared to mild patients.
Abstract
During viral infections, especially Covid-19, Tcell exhaustion plays a crucial role in reducing the activity of lymphocytes and the immune system's antiviral activities. This research aimed to investigate the co-inhibitory receptors and transcription factors involved in the Tcell exhaustion process in ICU-admitted (ICUA) compared to non-ICU admitted (non-ICUA) Covid-19 patients. A total of 60 Covid-19 patients (30 patients in the severe group who were admitted in the ICU (ICUA) and 30 patients in the mild group who were admitted in departments other than the ICU (non-ICUA)) and 10 healthy individuals were included in this study. Laboratory tests and the level of gene expressions related to 4 inhibitory co-receptors, including LAG-3, TIM-3, TIGIT, PD-1, and T-bet and Eomes transcription factors involved in the process of Tcell exhaustion in severe and mild patients of Covid-19 were investigated. The results showed lymphopenia and an increase in other hematologic laboratory factors such as NLR, PLR, CRP, ALT, and AST in people with a severe form of the disease (ICUA) compared to mild groups (non-ICUA) (P < 0.001). Furthermore, a significant increase in 3 co-inhibitory receptors, TIM-3, LAG-3, and PD-1, was observed in severe patients compared to mild and healthy people (P < 0.001). An increase in TIGIT gene expression was lesser than the other three mentioned receptors (P < 0.05). Concerning the transcription factors, we observed a significant increase in Eomes in ICUA patients compared to the non-ICUA group (P < 0.001), and this increment in T-bet gene expression was minor compared to Eomes (P < 0.05). In conclusion, Patients with a severe form of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represented a higher level of gene expressions in terms of co-inhibitory receptors and transcription factors involved in the T cell exhaustion process.
Graphical abstract
Abbreviations
PD-1
programmed cell death protein 1
LAG-3
lymphocyte-activation gene 3
TIM-3
T cell immunoglobulin and mucin domain-containing protein 3
TIGIT
T-cell immunoglobulin and ITIM domain
EOMES
eomesodermin
T-bet
T-box expressed in T
ICU
intensive care units
Keywords
Tcell exhaustion
Covid-19
Co-inhibitory receptors
Transcription factors
Data availability
All the data was used for the research described in the article