Abstract
Acute bronchiolitis is an acute respiratory infection which commonly occurs in infancy. Respiratory syncytial virus is the major cause of lower respiratory tract infection. Some other virus may be found during co-infections. The aim of this study was to search for biological markers correlated with gravity and risk factors for asthma and allergy. The follow-up was done during the multicenter and prospective study Bronchiolitis (PHRC 2000 No. 2000/020/HP), performed between November 2001 and January 2006, which included seven centers in France: Rouen, Le Havre, Lille, Elbeuf, Evreux, Brest and Saint-Nazaire associated with Nantes. Clinical and biological data were gathered during initial course, then at 1 month and 1 year. For the population of 209 infants, mean age was 3 months, the gravity was evaluated by scoring. The laboratory results correlated with clinical scoring were the following: viral evaluation, absolute numbers of leucocytes, lymphocytes and eosinophils, flow cytometry for sub-populations of lymphocytes, allergology including IgE, eosinophilic cationic protein, and basophil activation test. The results of the study are presented and discussed.