Exhaustion and over-activation of immune cells in COVID-19: Challenges and therapeutic opportunities

Adaptive immune dysfunction in patients with COVID-19 and impaired kidney function during the omicron surge

“…As a major subset of T lymphocytes, Th cells play a crucial part in the adaptive immune response by viral infections. Th cells modulate the activity of other immune cells, such as B cells, Ts cells, neutrophils, and macrophages in antiviral and immune activity [ 14 , 31 ]. Recent data have shown that Th cells can also act similarly to Ts cells, inducing cell death through interacting with peptides presented on MHC II [ 32 ].…”

“…Immune disorders take part in the pathogenesis of COVID-19 and lead to poor prognosis. Impaired adaptive immune response to viral infection, cytokine storm, and hyperinflammation status could result in systemic tissue injury, multiorgan disorder, and mortality [ 13 , 14 ]. Lymphocyte and its subsets play a crucial part in the immune response against viral infections.…”

Regulatory T Cells (Tregs) and COVID-19: Unveiling the Mechanisms, and Therapeutic Potentialities with a Special Focus on Long COVID

“…The so-called COVID-19 pandemic, which has caused severe damage to humankind, was caused by the novel form of the coronavirus named SARS-CoV-2. The SARS-CoV-2 infection has shown variability in the prognosis of the COVID-19 disease, which can cause flu-like symptoms, viral pneumonia, multiple organ damage, or acute respiratory distress syndrome (ARDS) [ 1 , 2 , 3 , 4 ]. Comparing the SARS-CoV-2 infection to earlier coronavirus infections, one may see unique patterns of cellular and humoral immunological abnormalities [ 1 , 4 ].…”

“…The SARS-CoV-2 infection has shown variability in the prognosis of the COVID-19 disease, which can cause flu-like symptoms, viral pneumonia, multiple organ damage, or acute respiratory distress syndrome (ARDS) [ 1 , 2 , 3 , 4 ]. Comparing the SARS-CoV-2 infection to earlier coronavirus infections, one may see unique patterns of cellular and humoral immunological abnormalities [ 1 , 4 ]. In the early and moderate phases, it may cause exhaustion of T cells, dendritic cells (DCs), and natural killer (NK) cells; however, excessive stimulation of such immune cells has been reported in severe instances, leading to a cytokine storm [ 5 ].…”

“…In the early and moderate phases, it may cause exhaustion of T cells, dendritic cells (DCs), and natural killer (NK) cells; however, excessive stimulation of such immune cells has been reported in severe instances, leading to a cytokine storm [ 5 ]. Cytokine storm has been proposed as the leading cause of death in COVID-19-infected patients [ 1 ].…”