After a brief review of airway inflammation mechanisms, the main results concerning the studies on airways inflammation in wheezing infants are commented. Infantile asthma differed from adult asthma by a predominance of neutrophils in airways, but less eosinophils or mastocytes. However, the presence of eosinophil or mastocyte markers does not allow to exclude a contribution of eosinophils in infantile wheeze. Studies on macrophages at cell level showed that a potent inflammation from macrophages exists in asymptomatic asthmatic infants. Lymphocyte subsets studies demonstrated a modulation of CD8 in these infants, suggesting the role of lymphocytes and the contribution of viruses in the pathophysiology of the disease. Lastly, the measurement of various mediators in airways confirmed that airway inflammation is present in infantile wheeze.