Lower lymphocyte response in severe cases of acute bronchiolitis due to respiratory syncytial virus

Abstract Introduction Acute bronchiolitis (AB) of the infant has a serious outcome in 6–16% of the hospital admitted cases. Its pathogenesis and evolution is related to the response of the T lymphocytes. The objective of the present study is to determine if the lower systemic lymphocytic response is related to a worse outcome of AB in hospitalised infants. Patients and method Retrospective observational-analytical study of cases–controls nested in a cohort of patients admitted due to RSV-AB between the period from October 2010 to March 2015. Those with a full blood count in the first 48 h of respiratory distress were included. Infants with underlying disease, bacterial superinfection, and premature infants Results The study included 252 infants, of whom 6.6% (17) required PICU admission. The difference in mean ± SD of lymphocytes for patients admitted to and not admitted to PICU was 4044 ± 1755 and 5035 ± 1786, respectively (Student- t test, P P  = 0.019; OR: 3.2) and it was found to be maintained in the logistic regression, regardless of age and all other studied factors (Wald 4.191 P  = 0.041, OR: 3.8). Conclusions A relationship was found between lymphocytosis