T cell immunobiology and cytokine storm of COVID-19.

Abstract

2019 coronavirus disease (COVID‐19) presents as a newly recognized pneumonia and could rapidly progress into acute respiratory distress syndrome which has brought about a global pandemic. Until now, no curative therapy has been strongly recommended for COVID‐19 except for personalized supportive care. T cells and virus‐specific T cells are essential to protect against virus infection, including COVID‐19. Delayed immune reconstitution (IR) and cytokine storm (CS) remain serious obstacles for the cure of COVID‐19. Most COVID‐19 patients, especially among elderly patients, had marked lymphopenia and increased neutrophils, but T cell counts in severe COVID‐19 patients surviving the disease gradually restored later. Elevated pro‐inflammatory cytokines, particularly IL‐6, IL‐10, IL‐2 and IL‐17, and exhausted T cells are found in peripheral blood and the lungs. It suggests that Thymosin α1 and adoptive COVID‐19‐specific T cells could improve IR, while convalescent plasma, IL‐6 blockade, mesenchymal stem cells and corticosteroids could suppress CS. More clinical studies in this field worldwide are urgently warranted to pave the way for therapy of COVID‐19 in the future.