Eosinophils and COVID-19 prognosis

Abstract

Since the discovery of COVID-19 in December 2019, many key questions were raised on the potential relationship between eosinophil count and the course and severity of COVID-19.

Evaluate the value of eosinophil count (EC) on admission as a predictive marker of severity, ICU transfer and death in Covid-19 patients

Retrospective study conducted from March 2020 to January 2021 in the pulmonary department B of Abderrahmen Mami hospital on confirmed COVID-19 pneumonia. We compared the clinical data, lab findings, including inflammatory markers, radiological findings, course and severity (mortality, ICU admission, and need for mechanical ventilation) in 2 groups: patients with eosinophilia (G1) to those without eosinophilia (G2).

One hundred ninety six cases of COVID-19 were included in our study, The median age was 61,32±2,5 years. The sexe-ratio was 1,8. The most common comorbidities were hypertension (46%),diabetes(40%) and obesity(32%). Laboratory tests revealed that 18.7 % had mild eosinophilia (500<EC <1500/μL). Patients with eosinophilia had significantly lower CRP (87 mg /dl vs 187 mg/dl ; p=0.04) and had usually mild CT severity (25-50%)(64% vs 12% ; p=0,05) compared to patients without eosinophilia. They also had a lower ICU admission (4% vs 51%; p=0,001), mechanical ventilation (4% vs 42% ; p=0,003) and mortality (3% vs 18%; p=0,05). The eosinophils count was correlated negatively with the duration of ICU admission, mechanical ventilation and with CRP level (r:- 0.34,-0.32,-0.61 and - 0.39, respectively) (p< 0.01).

Patients with eosinophilia had milder clinical course and better disease outcomes. This protective role of eosinophils needs to be validated by further prospective studies.