OBJECTIVE To explore the clinical significance of the changes of trace elements and erythrocyte immune function for the diagnosis of preschool children with recurrent respiratory tract infections,so as to provide reference for relevant research of recurrent respiratory tract infections.METHODS A total of 44 cases of children with recurrent respiratory tract infections from Dec.2010 to Dec.2013 were chosen as the study group,while 44 cases of healthy children at the same period had examination were as the co...