Objective To compare the changes of B lymphocyte subsets in children before and after allergen immunotherapy( AIT),and to clarify the role of B cell subsets in AIT treatment. Methods Flow cytometry was used to detect the number of B lymphocyte subsets in 32 children before and after allergen immunotherapy. Thirty-two healthy children with matched age and sex were selected as the control group. Results The relative and absolute numbers of activated B lymphocytes were significantly lower than those before tre...