Researchers at the Berlin Institute of Health (BIH) and the Charité Hospital, together with colleagues from university hospitals in Bonn and Aachen, have linked a certain type of T cells with especially deadly cases of the disease caused by the coronavirus.
The culprit is a molecule called CD16, which the scientists discovered on the T cells of patients suffering from particularly severe Covid-19. Normally, CD16 helps the immune system recognize recognize and kill virally infected cells. But its presence is harmful in the case of the coronavirus.
“It’s dangerous because T cells have a built-in safety mechanism,” said Brigit Sawitzki, director if the NIH’s department of translational immunology, in a statement. “With their T-cell receptors, they recognize foreign protein elements so that their activity is directed only at infected or altered bodily cells. When they are activated by CD16, this safety mechanism is disabled, and non-infected vessel cells can be attacked as well.”
“We seem to have discovered an important new connection,” she added. “If this connection is confirmed, inhibiting the complement system [part of the immune system] could help minimize severe cases [of the disease].”