title: Occurrence of C3 nephritic factor and C4 nephritic factor in membranoproliferative glomerulonephritis (MPGN).
abstract: One hundred patients diagnosed with hypocomplementaemic MPGN (C3 < 40%) were studied to determine the presence of C3 nephritic factor (C3NeF) and/or C4 nephritic factor (C4NeF). Of those studied, 12 were C3NeF-positive, nine were C4NeF-positive and 10 were positive for both C3NeF and C4NeF. In the 10 patients both C3NeF- and C4NeF-positive, a marked decrease in C3 and C5 levels and a decrease in levels of late components from C6 to C9 were observed. This observation was in contrast to that seen in patients who were either C3NeF- or C4NeF-positive. Patients positive for both C3NeF and C4NeF continued to exhibit hypocomplementaemia after therapy. Immunofluorescent findings revealed heavy C3 immunoglobulin deposits in the 10 patients who were both C3NeF- and C4NeF-positive, whereas no such deposits were found in those patients who were either C3NeF- or C4NeF-positive only. When those patients who were both C3NeF- and C4NeF-positive were compared with those who were either C3NeF- or C4NeF-positive, nephritic syndrome and a poor prognosis were observed more frequently. This study demonstrates a correlation between clinical outcome and hypocomplementaemic MPGN. Further investigations of MPGN as an autoimmune disease are necessary.
authors.affiliation: Department of Internal Medicine II, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohi
authors.forename: T
authors.initials: T
authors.lastname: Yasugi
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D003176:Complement C3 / Q000032:analysis; D003178:Complement C3 Nephritic Factor / Q000032:analysis*; D003165:Complement System Proteins / Q000032:analysis*; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology*; D006801:Humans
chemical_list: D001323:Autoantibodies; D003176:Complement C3; D003178:Complement C3 Nephritic Factor; C058872:complement 4 nephritic factor; D003165:Complement System Proteins