Serum tumor necrosis factor-alpha concentrations in children hospitalized for acute lower respiratory tract infection.

Tumor necrosis factor-alpha (TNF alpha) concentrations were measured by radioimmunoassay in sera of 118 children (median age, 1.7 years; range, 2 months-15 years) hospitalized for acute lower respiratory tract infection (ALRI). Both viral and bacterial ALRI were associated with elevated concentrations of TNF alpha. Concentrations greater than 40 ng/l were seen in children with bacterial or mixed ALRI in 64% and with viral ALRI in 50% of cases. Elevated concentrations were associated with longer duration of fever before admission (P less than .05) and with a higher serum C-reactive protein concentration (P less than .05). There were no significant differences in TNF alpha concentrations between gram-positive and gram-negative infections, nor was there an association with clinical severity of ALRI. TNF alpha concentrations decreased in most patients to normal within 5 days of hospitalization, irrespective of the etiology of the infection.