COVID-19 Recoverees Show Sustained Cellular Immune Dysregulation

Investigative studies looking at underlying immune characteristics are needed to understand disease pathogenesis.

SARS-CoV-2, the virus which causes the coronavirus disease 2019 (COVID-19), has troubled physicians and investigators alike due to its abnormal path which is rarely uniform. Infected patients can have mild or no symptoms at all, while others can develop severe disease.

Observational clinical research has become a central priority to help gain a better understanding of how the virus acts, which will help to inform new therapies to treat the ongoing pandemic.

In a recent study published in the Journal of Clinical Investigation, investigators at the University of Alabama at Birmingham found that some individuals who are recovering from an infection from COVID-19 show sustained cellular immune dysregulation.

The team of investigators gathered blood samples, along with clinical data, from 46 patients who were hospitalized with an active COVID-19 infection and 39 who had been discharged and were recovering. The two groups were compared against healthy individuals who were tested and had a negative result.

They then separated from the blood samples separate specific immune cell subsets, allowing them to analyze surface markers on the cells. With the information obtained, immunologists are able to see how immune systems in individuals respond during an infection and during convalescence. This can help reveal whether immune cells have become activated and exhausted, which may increase susceptibility to a secondary infection or worsen the development of protective immunity to the disease.

Investigators were also able to observe changes in the immune system over time, and found that the non-hospitalized patients had activated upregulated markers and several activated and exhausted markers were expressed at higher frequencies, showing apparent immune dysregulation.

The investigators plan on further research looking at whether the observed immunologic changes are associated in anyway with symptoms experienced beyond the acute infection, which has been called “Long COVID”.

"The importance of these studies to provide context for the interpretation of immune responses generated by participants in COVID-19 vaccine trials, including how those responses change over time, cannot be over-emphasized,” Phillip Mudd and Kenneth Remy said in a commentary on the study. “This information will be key in potential modifications to existing COVID-19 vaccines and treatments."