title: Decrease of helper T cells in children with recurrent respiratory tract infections.
mesh_terms: D002648:Child; D002675:Child, Preschool; D006801:Humans; D007958:Leukocyte Count; D012008:Recurrence; D012141:Respiratory Tract Infections / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer