Aumento de interleuquinas proinflamatorias y de cortisol plasmático en bronquiolitis por virus respiratorio sincicial: relación con la gravedad de la infección / Levels of inflammatory cytokines and plasma cortisol in respiratory syncytial virus bronchiolitis

Background: An increased inflammatory innate response may play a role in pathogenesis of respiratory syncytial virus (RSV) infection. Aim: To quantify pro-inflammatory cytokines (IL-6-IL-8, ÍL-2-P and TNF-a) in nasopharyngeal aspirate (NPA) and plasma, and plasma cortisol in previously healthy infants with RSV bronchiolitis. Patients and Methods: We studied 49 infants aged less than one year of age with RSV bronchiolitis and 25 healthy controls. Severity was defined using a previously described modified score. We quantified interleukins in NPA and plasma by flow cytometry and plasma cortisol by radioimmunoanalysis. Results: Among patients with RSV bronchiolitis, 25 were classified as severe and 24 as moderate or mild. Significantly higher levels ofIL-6 and IL-8 in NPA and plasma and IL-lfi in NPA were found in children classified as severe, when compared to those with moderate or mild disease and controls. There was a positive correlation between IL-6 and cortisol in plasma (r = 0,55; p < 0,0001) and both were correlated with the severity of the disease. Conclusions: RSV bronchiolitis severity was associated with higher levéis of inflammatory interleukins and plasma cortisol.

Plasma endothelin-1 in infants and young children with acute bronchiolitis and viral pneumonia.

Respiratory syncytial virus (RSV) Infections that occur during the first three years of life have been demonstrated to be associated with the development of childhood asthma. The mechanism of virus-triggered airway inflammation Is not fully understood. Endothelin-1 is a potent bronchoconstrictor involved in many diseases including respiratory tract infections. Infants and young children diagnosed with either viral pneumonia or acute bronchiolitis, their age ranging between 2 months and 3 years, were recruited into this study. Nasopharyngeal aspirates were taken for detection of respiratory virus by antigen immunofluorescence stain, RT-PCR analysis and viral culture. Plasma endothelin-1 (ET-1) was measured by using a commercially available enzyme-linked immunosorbent assay (ELISA). Ten of the nineteen infants and children (52%) were positive for RSV infection, one co-infected with influenza A. Nine Infants (90%) were positive for RSV subtype A. There was only one infant with subtype B. One of the RSV negative individuals was positive for influenza A. In addition, we recruited 10 patients without chronic underlying or respiratory tract illness as controls. ET-1 levels were significantly increased in RSV infection compared to the controls (3.6 +/- 1.2 and 1.2 +/- 1 pg/ml, respectively (p < 0.05). In conclusion, infants and young children who are infected with RSV have an increase in circulating plasma endothelin-1. This in turn may contribute to the subsequent development of childhood asthma.