Role of IL-6 Levels in Predicting the Severity of Dengue Fever

Interleukin-6 (IL-6) may generate anti-platelet and anti-endothelial autoantibody coagulation defects leading to bleeding and plasma leakage in dengue infection. Vachher H. et al., in their study, included 60 children aged six months to 18 years and categorized them into nonsevere dengue (NSD) and severe dengue (SD) according to WHO 2009 Dengue Severity Criteria to assess whether IL-6 levels can predict the severity of dengue fever. They assessed the mean IL-6 levels on the 1st and 4th day of admission using enzyme-linked immunosorbent assay kits.

They found that among 60 patients, 25% belonged to SD on day 1 of admission, 16.67% belonged to SD on day 4, and 10% of patients expired within four days of admission. IL-6 levels of 616.1680 ± 449.0418 pg/ml (Mean ± Standard Deviation) on day 1 of admission and 747.2799 ± 558.9062 pg/ml (Mean ± Standard Deviation) on day 4 of admission corresponded to SD. Also, they observed that IL-6 levels on day 1 of admission of >265.4565 pg/ml were witnessed to predict mortality with a sensitivity of 67.30%, specificity of 75.00%, negative predictive value (NPV) of 26.09%, and positive predictive value (PPV) of 94.59%. On day 4 of admission, IL-6 levels of >495.7575 pg/ml were observed to predict mortality with a sensitivity of 84.62%, specificity of 100.00%, NPV of 20.00%, and PPV of 100.00%. Suharti et al. also showed increased IL-6 in dengue shock syndrome (DSS) non-survivors. 

This study clarifies that IL-6 levels at presentation can predict the severity of dengue and its clinical outcome with high diagnostic accuracy. Thus, IL-6 levels of >450 pg/ml on day 4 of admission should raise a high index of suspicion for a poor clinical outcome (mortality) in dengue fever.

Vachher H, Metgud T, Srikanth B. IL-6 Levels in Prediction of Severity of Dengue Fever. Indian J Pediatr. 2023. https://doi.org/10.1007/s12098-023-04514-y