title: Serum complement components in Henoch-Schönlein purpura.
abstract: Serum levels of C1q, C4, C3, C5, factor B, and properdin were measured in patients with Henoch-Schönlein purpura (HSP). In the cases of acute HSP, 9 of 23 (39%) had a low CH50, and 5 of 17 (30%) a low properdin; C1q, C4, and C3 levels were not depressed. In 10 cases with chronic nephritis following HSP, complement components were normal except for 2 with reduced C4 and one with low properdin. These findings confirm that complement activation occurs in HSP; the low serum levels of properdin in the acute group indicate that there is activation of the alternative pathway in these patients.
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003172:Complement C1 / Q000032:analysis; D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D003182:Complement C5 / Q000032:analysis; D011415:Complement Factor B / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis*; D006801:Humans; D011695:IgA Vasculitis / Q000276:immunology*; D009393:Nephritis / Q000276:immunology; D011414:Properdin / Q000032:analysis
chemical_list: D003172:Complement C1; D003176:Complement C3; D003181:Complement C4; D003182:Complement C5; D011414:Properdin; D003165:Complement System Proteins; D011415:Complement Factor B