The CXCL9/10/11-CXCR3 axis as a predictor of COVID-19 progression: a prospective, case-control study

Background: This study examined the relationship between levels of the chemokines CXCL9, CXCL10, CXCL11, and CXCR3 and mortality in patients with COVID-19.. Methods: A total of 71 patients hospitalized with COVID-19 and 35 health workers with no symptoms and negative SARS-CoV-2 PCR results were included in the study. CXCL9, CXCL10, CXCL11, and CXCR3 levels were measured in blood samples using enzyme-linked immunosorbent assays. Participants were divided into three groups: healthy individuals, patients with mild to moderate pneumonia, and patients with severe pneumonia. Patients were also divided into sub-groups according to the outcome: dead and survived. Results: Serum CXCL9, CXCL10, CXCL11, and CXCR3 levels were significantly higher in patients with severe COVID-19 than in those with non-severe COVID-19; were higher in both patient groups than in the control group; and were higher in patients who died than in those who survived. Lymphocyte counts, and fibrinogen and PaO2 /FiO2 levels were significantly lower in patients with severe COVID-19 than in those with moderate disease. Patients with COVID-19 also had elevated neutrophil/lymphocyte ratios, neutrophil counts, and lactate dehydrogenase, C-reactive protein, D-dimer, and ferritin levels. Conclusions: This study confirmed that CXCL9, CXCL10, CXCL11, and CXCR3 levels are associated with disease severity in patients with COVID-19. These laboratory parameters can help to estimate disease severity and predict outcomes, and are useful in clinical decision-making.