Bronchoalveolar interleukin-1 beta: A marker of bacterial burden in children with community-acquired pneumonia (CAP)

Objective: To assess the relationship between concentrations of bronchoalveolar cytokines and bacterial burden in children with CAP. Method: 58 children were divided into two subgroups: referral (n=28), and treated (n=30) CAP. Bronchoalveolar lavage was performed in the most abnormal area on chest radiograph by fiberoptic bronchoscope. Bronchoalveolar lavage fluid was processed for quantitative bacterial culture. The concentrations of bronchoalveolar lavage cytokines (tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6, interleukin-8, and interleukin-10) also were measured. Results: Thirty-two patients had a positive bacterial culture (bronchoalveolar lavage > or = 10 colony-forming units/mL), and made up 76% of pathogens recovered at high concentrations. The concentrations of bronchoalveolar lavage interleukin-1 beta were 181.1±16.3 and 45.1±10.6 pg/mL (mean ± se) in the children with positive and negative bacterial culture, respectively (p <.001). Bronchoalveolar lavage interleukin- 1 beta was significantly higher in the children with a high bacterial burden (p <.001), with mixed bacterial infection (p <.001), and with CAP (p <.001), compared with values in patients without these features. The relationship between bacterial load and concentrations of bronchoalveolar lavage interleukin-1 beta was very strong in the children with referral CAP but was borderline in treated CAP. Conclusions: Concentration of bronchoalveolar lavage interleukin-1 beta was correlated with bacterial burden in the alveoli, it may be a marker for progressive and ongoing inflammation in children who have not responded to CAP therapy.