Dr. Zein speaks of the relationship between eosinophil count and COVID-19 illness and mortality, especially as it related to inhaled corticosteroid use.
Recent literature on eosinophilia has hypothesized that an absolute eosinophil count >0.15 x103 cells/mL could result in protection against severe COVID-19 illness and mortality in patients with asthma.
In a new study, Joe Zein, MD, PhD, MBA, Department of Pulmonology at the Cleveland Clinic, evaluated the relationship between eosinophils and asthma as well as inhaled corticosteroid use among asthma patients.
The findings, which will be presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting (AAAAI) in Phoenix, noted that the association between eosinophilia and improved outcomes in COVID-19 was reliant on inhaled corticosteroid therapy.
“There was always a concern that people with low eosinophils may have issues with COVID-19,” Zein said. The reason is, we know eosinophils are not only there for allergy or for parasitic infection, they also have an antiviral effect…So this is why it was interesting to see whether they also fill have any role and COVID-19, and whether they are associated with better outcomes.”
Zein and colleagues examined a total of 46,397 patients, 19,506 of whom had eosinophilia and 5,011 of who received inhaled corticosteroids. From there, the team conducted a multivariate analysis that associated eosinophilia with lower risk of hospitalization and ICU admission, but only in asthma patients treated with inhaled corticosteroids.
Additionally, the increased risk of worse COVID-19 outcomes in patients with high eosinophils was mitigated by inhaled corticosteroid use. Zein recommended that future randomized controlled studies be conducted to support these findings.
“I think our paper has 2 messages, the first one (is that) your baseline immune profile or immune cell profile will kind of predict your outcome, and people who have a normal eosinophil count somewhere between 100 to 300, (they) have the best outcome,” Zein said. “The second one related to inhaled corticosteroids. We cannot make any recommendations at this time, (but) this was our message: If someone wants to start a study to check for the effect of inhaled corticosteroid in asthma and in COVID-19 they have to adjust or stratify that analysis by eosinophil (count).”
To hear more from Dr. Zein on the dynamic between iCS, eosinophilia, and COVID-19, watch the interview above.