IgG subclasses and complement pathway in segmental and global membranous nephropathy.
The aim of our study was to clarify the association between immunoglobulin G(IgG) subclasses and the complement pathway in patients with idiopathic membranous nephropathy (MN). Immunofluorescence (IF) was performed in 16 MN patients and 20 controls using antibodies against IgG, IgA, IgM, C1q, C3c, C4d, IgG1, IgG2, IgG3, IgG4, mannose binding lectin (MBL), C4-binding protein (C4-bp), factor B, C5b-9, and CD59. MN was classified into two types, segmental MN (S-MN; six patients) and global MN (G-MN; ten patients), according to the distribution of IgG deposits along the glomerular capillary wall. No deposition of any antibody was found in the controls. IF revealed IgG1, IgG3, C1q, C3c, C4d, C4-bp, C5b-9, and CD59 deposits in patients with S-MN, whereas IgG1, IgG2, IgG3, IgG4, C3c, C4d, MBL, factor B, C4-bp, C5b-9, and CD59 deposits were detected in those with G-MN. There was a higher deposition of IG1, IgG2, and IgG4 in patients with G-MN than in those with S-MN, whereas the intensity of C1q deposits was higher in S-MN than in G-MN patients. In contrast, the intensity of factor B and MBL was higher in G-MN than in S-MN patients. This is the first report of S-MN patients showing complement activation of the classical pathway associated with IgG1 and IgG3 and G-MN patients showing complement activation of both the alternative and lectin pathways associated with IgG2 and IgG4.
Department of Pathology, Faculty of Medicine, Fukuoka University, Nanakuma 7-45-1, Jonan-ku, Fukuoka City, 814-0180, Japan.
Yoshie
Y
Segawa
Satoshi
S
Hisano
Misao
M
Matsushita
Teizo
T
Fujita
Shinichi
S
Hirose
Morishige
M
Takeshita
Hiroshi
H
Iwasaki
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003165:Complement System Proteins / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D015433:Glomerulonephritis, Membranous / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D055815:Young Adult
D007074:Immunoglobulin G; D003165:Complement System Proteins