title: Letter: C3 in cystic fibrosis.
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003176:Complement C3 / Q000032:analysis*; D003165:Complement System Proteins / Q000032:analysis*; D003550:Cystic Fibrosis / Q000276:immunology*; D006801:Humans; D007223:Infant
chemical_list: D003176:Complement C3; D003165:Complement System Proteins