Interleukin-18 binding protein in infants and children hospitalized with pneumonia in low-resource settings.

Abstract

Pneumonia is the leading infectious cause of death in children, with especially high mortality in low- and middle-income countries. Interleukin-18 binding protein (IL-18BP) is a natural antagonist of the pro-inflammatory cytokine interleukin-18 and is elevated in numerous autoimmune conditions and infectious diseases. We conducted a prospective cohort study to determine the association between admission IL-18BP levels and clinical severity among children admitted to two hospitals in Uganda for hypoxemic pneumonia. A total of 42 children (median age of 1.2years) were included. IL-18BP levels were higher in patients with respiratory distress, including chest indrawing (median 15ng/mL (IQR 9.8-18) versus 4.5ng/mL (IQR 3.8-11) without chest indrawing, P=0.0064) and nasal flaring (median 15ng/mL (IQR 9.7-19) versus 11ng/mL (IQR 5.4-14) without nasal flaring, P=0.034). IL-18BP levels were positively correlated with the composite clinical severity score, Pediatric Early Death Index for Africa (PEDIA-e, ρ=0.46, P=0.0020). Patients with IL-18BP>14ng/mL also had slower recovery times, including time to sit (median 0.69days (IQR 0.25-1) versus 0.15days (IQR 0.076-0.36) with IL-18BP<14ng/mL, P=0.036) and time to fever resolution (median 0.63days (IQR 0.16-2) versus 0.13days (IQR 0-0.42), P=0.016). In summary, higher IL-18BP levels were associated with increased disease severity and prolonged recovery times in Ugandan children with pneumonia.