Serum IL-6 levels were significantly elevated in children with pneumonia (median: 47.37 ng/L, IQR: 32.63–61.63) compared to controls (median: 13.14 ng/L, IQR: 9.69–17.19; p < 0.001), with a threshold of >18.06 ng/L achieving 96% sensitivity and 100% specificity. The gene discussed is IL6; the disease is pneumonia.