To evaluate the relationship between clinical parameters and differential cell counts, bronchoalveolar lavage was performed in 79 asthmatic infants and children with unusual asthma. Multivariate analysis showed significant associations between (1) allergic asthma and the presence of alveolar eosinophils and (2) persistent and longer asthma and an increased number of alveolar neutrophils. Our results provide the first evidence that in asthmatic infants and children eosinophilic inflammation is related to allergic sensitization.