Thursday June 11, 2020
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Some people rarely develop symptoms after being infected with the coronavirus, others become life-threatening. The blood values can be used to make predictions about the course of the disease. This would enable risk patients to be identified early and treated more effectively.
With Covid-19 disease, two types of immune cells in the blood can be used to predict whether a patient will develop severe or mild symptoms. This is the result of a study on 40 Covid-19 patients in Wuhan, China. The findings have been confirmed in several patients in Germany, says co-author Ulf Dittmer, director of the Institute of Virology at Essen University Hospital and Vice President of the Society for Virology. Several media had previously reported on the study published in the journal “EBioMedicine”.
According to Dittmer, one of the two types of immune cells is a so-called killer T cell with a certain surface marker (CD8). They kill virus-infected body cells and thus interrupt the multiplication of the coronavirus Sars-CoV-2. “If the patients have only a few of these cells, they are at high risk of developing severe symptoms such as pneumonia or coagulation disorders,” explains Dittmer.
The other cell type are so-called neutrophils. “They are actually there to ward off bacteria. But they can also suppress the function of T cells.” Accordingly, only a few T cells were found in blood samples with many neutrophils, which was associated with a more severe course of the disease. “Patients with pre-existing conditions that lead to a decrease in the number of T cells, such as patients after transplants who receive medication to suppress rejection reactions, were particularly affected,” says Dittmer.
Cancer patients under chemotherapy, the elderly with a decrease in the number of T cells due to age, or obese patients are also affected. “We know that overweight people have weaker and fewer T cells.” At the University Hospital Essen, more than 70 percent of the severe Covid 19 courses were overweight men.
Patients are missing for a more detailed study
For Covid-19 therapy, this means that one could try to stimulate the killer T cells at the beginning of an infection – certain vaccines could do that. Vitamins A and C could also improve the function of T cells. In the case of transplant patients, the dose of the drugs for defense suppression could be reduced, in cancer patients one would have to interrupt the chemotherapy in the case of a Sars-CoV-2 infection.
Dittmer emphasized that a more detailed study on this is now difficult in Germany because fortunately there are not enough patients anymore. For example, in the last week of May at Essen University Hospital there was not a single new Covid 19 admission, and only one in the first week of June.
The immunologist Michael Lohoff, who was not involved in the study, sees the finding as positive. “A safe test that would allow a prognostic statement about the expected severity of a Covid 19 disease would be very helpful,” emphasizes the director at the Institute for Medical Microbiology and Hospital Hygiene at the University of Marburg.
One could then admit patients at risk early and receive intensive medical treatment if necessary. “The findings of the study are quite attractive here.” However, the number of patients examined is very small, says Lohoff. “You should definitely confirm this finding in other patients, preferably in another part of the world – to exclude any possible contribution from the patient’s genetics.”
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