OBJECTIVE: To analyze the cellular pattern of nasopharyngeal secretions in infants with acute bronchiolitis (AB), focusing on the presence or absence of neutrophils and eosinophils. METHODS: Hospitalized children with AB admitted to Hospital São Lucas, Porto Alegre, Brazil, between May and July 2002 were recruited. Nasopharyngeal aspirates were collected during the first 48 hours after admission. Slides were stained with May Grunwald and Giemsa. Total cell count and cellular viability were obtained in all samples. RESULTS: Thirty-eight infants with AB were enrolled. The mean age was 2.2 months (interquartile range: 1.2-3.5), and 21 subjects were male. Neutrophils were the predominant cells in the nasopharyngeal aspirates (median 95%, interquartile: 94-97). No eosinophils were found in the samples studied. CONCLUSIONS: Our results suggest that eosinophils do not play a significant role in the pathophysiogenesis of AB. Infants with AB present a specific inflammatory response to viral infections, which is distinct from the immune response observed in asthma.
Acute bronchiolitis; inflammation; neutrophil; eosinophil
