RESUMO
OBJECTIVES: The Bruton tyrosine kinase (BTK), an important element for the production of several inflammatory cytokines, may play a role in the pathogenesis of COVID-19. The aim of this study was to investigate the level of BTK gene expression in COVID-19 cases based on the severity and the outcome of the disease. METHODS: In this study, 33 hospitalized patients with COVID-19 were recruited and were divided into two groups based on the severity of the disease: "mild to moderate" and "severe to critical". A blood sample was taken from each patient, peripheral blood mononuclear cells (PBMCs) were extracted, and BTK gene expression was measured. The level of BTK gene expression was compared based on the demographic data, laboratory results, and the severity and outcome of the disease. RESULTS: Among 33 patients, 22 (66.7%) were male. Nearly half of the cases had at least one underlying disease. According to the severity of the disease, 12 patients were in the "mild to moderate" group, and 21 were in the "severe to critical" group; eight (24.2%) eventually died. Age, weight, and BMI had no significant relationship with BTK expression. BTK expression was significantly lower in "severe to critical" and ICU-admitted cases and in subjects with low O2 saturation. There was no significant difference in BTK expression between cured and dead patients (p=0.117). CONCLUSION: BTK gene expression in PBMCs had an inverse relationship with the severity of the disease of COVID-19. However, no correlation between BTK expression and disease outcome was observed.