A new observational study on Covid-19 stated that there has been a sustained cellular immune dysregulation reported in individuals who are recuperating from the infection.
The researchers from the University of Alabama, Birmingham, obtained blood samples and clinical data from 46 hospitalised Covid-19 patients and 39 non-hospitalised individuals who had recovered from confirmed Covid-19 infection. Both groups were compared to healthy, Covid-19-negative controls.
Their study, published in the journal Clinical Investigation, analysed how each individual’s immune system is responding during infection and during convalescence.
The researchers were able to analyse changes over time, in two ways. The first was observing changes in surface markers over time, defined as days since the onset of symptoms for non-hospitalised samples.
The second was directly comparing the frequencies of these markers between the first and second clinic visits for non-hospitalised patients who had blood samples collected at two sequential time points.
The most surprising finding involved non-hospitalised patients. The researchers saw upregulated activation markers in hospitalised patients. But they also found several activations and exhaustion markers were expressed at higher frequencies in non-hospitalised convalescent samples.
Looking at these markers over time, it was apparent that immune dysregulation in the non-hospitalised individuals did not quickly resolve, the researchers stated in their study.
Notably, this dysregulation of T cell activation and exhaustion markers in the non-hospitalised cohort was more pronounced in the elderly.
“To our knowledge, this is the first description of sustained immune dysregulation due to Covid-19 in a large group of non-hospitalised convalescent patients,” the researchers reported.
They also speculate that the immune dysregulation could also be associated with the Long Covid.