Nasopharyngeal aspirate & blood cytokine profile in infants hospitalized for respiratory syncytial virus bronchiolitis: A pilot study from south India.

BACKGROUND & OBJECTIVES: Following a respiratory syncytial virus (RSV) bronchiolitis, only some infants develop serious illness, and a proportion of them develop recurrent wheeze subsequently. Studies have revealed that cytokine expression following RSV infection may influence the severity and also the risk for subsequent reactive airway disease. This present study was conducted to determine the blood, and nasopharyngeal aspirate (NPA) cytokine profile among infants admitted for RSV bronchiolitis. METHODS: In this prospective pilot study, a sample size of 15 cases and 15 controls was included. Detailed history, physical examination, blood sample and NPA collection were done. Cytokines (IFNγ and IL-4) estimation was done in the blood and NPA samples of cases and blood samples of controls. RESULTS: The mean levels of interferon gamma in controls (blood) and cases (NPA and blood) were 5.95, 9.54 and 32.02 pg/ml, respectively. The mean levels of interleukin-4 in controls (blood), and cases (NPA and blood) were 1280.77, 956.08 and 692.37 pg/ml, respectively (P<0.05). INTERPRETATION & CONCLUSIONS: Our study showed that infants with RSV bronchiolitis evoked a Th1 response in both blood and NPA. Large multicentre studies are needed to validate our findings.