A new study suggests immune responses to coronavirus in severely ill and critically ill patients are as strong or stronger than those of patients with milder illness. This adds to the evidence that the immune system itself is to blame for the most life-threatening form of the infection.
Immune cells known as T cells are responsible for recognizing pathogens, killing infected cells, and recruiting other branches of the immune system to combat infections.
However, according to the new study, T cell responses to the new coronavirus in critically ill patients appear to be just as robust as those with a less severe form of the illness.
The finding reinforces the conclusion that an inadequate immune response to SARS-CoV-2, the coronavirus that causes Covid-19, is not responsible for critical illness and death. Rather, an excessive immune response is to blame.
The team of researchers, led by Marien Hospital Herne and Ruhr-Universität Bochum in Herne, Germany, compared the T cell responses of 28 Covid-19 patients during the acute phase of the infection and after recovery in survivors. Of these infections, 7 were categorized as moderate, 9 were severe, and 12 were critical.
The scientists measured the concentration of two T cell types in blood samples from each patient: helper T cells and killer or “cytotoxic” T cells.
They also analyzed the strength of these cells’ responses to three distinct parts of the virus: the three proteins that make up its spikes, its membrane, and the shell or “nucleocapsid” surrounding its nuclear material.
PROMISING RESULTS FOR RUSSIAN VACCINE
A Covid-19 vaccine trialed in Russia elicited an immune response in all participants and caused no serious side effects. Still, confirming that the vaccine protects against the disease will require larger trials.
The number of Covid-19 cases in the United States has now passed 6 million, and the global total has exceeded 27 million.
With winter around the corner, hopes for an effective vaccine against Covid-19 are mounting. A vaccine developed at the Gamaleya Research Institute of Epidemiology and Microbiology, in Moscow, has received a lot of attention, though not all of it has been positive. The vaccine is based around an adenovirus, one from a family of viruses responsible for the common cold.
The researchers weakened the virus so that it cannot cause disease and modified it to express the spike protein from SARS-CoV-2, the virus that causes Covid-19.
