A small study of high-risk COVID-19 patients may help explain why their health issues contribute to more severe cases of the illness. Chronic conditions like obesity, diabetes, liver disease, hypertension, and heart disease also cause inflammation. Researchers studied 16 COVID-19 patients with these conditions and found in all of them the enzyme caspase-1 and the inflammatory protein IL-18 – evidence of an immune-system process called the inflammasome, which leads to decreases in immune cells and a form of cell death called pyroptosis.

On top of their pre-existing inflammation, inflammasome activation may be what brings on the “hyper inflammation” and immune dysfunction that makes these patients so severely ill, the researchers from MedStar Georgetown Transplant Institute (MGTI) in Washington, DC and SUNY Downstate Medical Center in Brooklyn suggested.

Because the inflammasome plays a role in other viral infections, “there has been … speculation about the inflammasome and SARS-CoV-2 for many months,” coauthor Dr Alexander Kroemer of MGTI told Reuters, adding that his team is the first to demonstrate an activated inflammasome in COVID-19 patients.

These findings, published on Monday in the Journal of Hepatology, “help to explain why vulnerable patient groups are so severely affected by COVID-19,” he said.

Only certain patients likely to benefit from antibody-rich plasma

Doctors may need to be more selective about who to treat with blood plasma from recovered COVID-19 patients, with a preference toward those whose symptoms have just begun, new research suggests. Researchers have been testing whether infusions of antibody-rich convalescent plasma can help COVID-19 patients recover faster. Investigators in The Netherlands said they stopped their convalescent plasma trial prematurely after only 86 hospitalised patients had been enrolled because nearly 80 per cent were found to already have their own neutralising antibodies.

“These observations caused concerns about the potential benefit of convalescent plasma in the study population,” the authors wrote in a paper posted on medRxiv in advance of peer review. Half of the patients in the study had been symptomatic for more than 10 days before being hospitalised. Given the high prevalence of neutralising antibodies at hospital admission, they added, “screening for antibodies and prioritising convalescent plasma to risk groups with recent symptom onset will be key to identify patients that may benefit from convalescent plasma.”