Inflammatory response in COVID-19 responsible for acute respiratory distress syndrome (ARDS) and multiorgan failure and play a major role in morbidity and mortality of patients. The present study was undertaken to assess serum level of cytokines and its association with other inflammatory markers and disease severity in COVID-19 and hence their prognostic significance.
This was a retrospective observational study of 175 admitted COVID-19 patients. The patient’s clinical data, laboratory investigations, inflammatory markers and serum level of cytokines [interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10) and tumour necrosis factor α (TNFα)] were extracted from their medical records. All patients were divided into three groups viz. group A had asymptomatic patients, group B had mild to moderate ill patients and group C had severe or critical ill patients. Above parameters were analysed and comparative evaluation with severity of disease was done.
& In present study 55% patients were asymptomatic, 24% patients were mild to moderate illness and remaining 21% patients had severe or critical illness. Fever, cough, dyspnoea and co-morbidities including hypertension and diabetes were more common in group C. Absolute lymphocyte count (ALC), lymphocyte monocyte ratio (LMR) showed decreasing trend whereas absolute neutrophil count (ANC), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and eosinophil-lymphocyte (ELR) showed increasing trend with increase in disease severity. Serum IL-6 was found to be significantly higher in group C (64.98±111.18pg/mL) as compared to group B (15.51±20.66pg/mL) and group A (5.04±56.1pg/mL) (P<0.001). Receiver operating characteristic (ROC) curve for IL-6 to differentiate the patients with severe disease from asymptomatic and mild symptomatic disease showed a cut-off of 6.75pg/ml.
Elevated IL-6 levels lead to adverse clinical events so IL-6 level might serve as a potential prognostic marker for severity of disease in COVID-19. Inhibition of IL-6 might be helpful to prevent serious adverse events in COVID-19 infection.

© Journal of the Association of Physicians of India 2011.