Complement activation is involved in renal damage in human antineutrophil cytoplasmic autoantibody associated pauci-immune vasculitis.
OBJECTIVE
This study was to investigate the evidence for complement activation in renal biopsy specimens of patients with myeloperoxidase (MPO)-antineutrophil cytoplasmic autoantibody (ANCA)-associated pauci-immune vasculitis.


METHODS
Renal biopsy specimens from seven patients with MPO-ANCA positive pauci-immune necrotizing crescentic glomerulonephritis (NCGN) were used to detect the staining of membrane attack complex (MAC), C3d, C4d, mannose-binding lectin (MBL), factor B and factor P using immunohistochemistry and immunofluorescence. Renal tissue from seven patients with minimal change disease (MCD) and two normal renal tissue were used as controls.


RESULTS
MAC, C3d, factor B and factor P could be detected in glomeruli and small blood vessels with active vasculitis of patients with pauci-immune AAV, but not or scarcely in patients with MCD and in normal renal tissue. C3d and factor B co-localized with MAC, factor P colocalized with C3d. MBL and C4d were not detected in patients with AAV.


CONCLUSIONS
The alternative pathway of the complement system is involved in renal damage of human pauci-immune AAV.
Xing
Guang-qun
GQ
Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, China.
Chen
Min
M
Liu
Gang
G
Heeringa
Peter
P
Zhang
Jun-jun
JJ
Zheng
Xin
X
E
Jie
J
Kallenberg
Cees G M
CG
Zhao
Ming-hui
MH
D000293:Adolescent; D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood* / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D003167:Complement Activation; D011415:Complement Factor B / Q000276:immunology / Q000378:metabolism; D015938:Complement Membrane Attack Complex / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000276:immunology* / Q000473:pathology; D008297:Male; D037601:Mannose-Binding Lectin / Q000276:immunology / Q000378:metabolism; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D011414:Properdin / Q000276:immunology / Q000378:metabolism; D014657:Vasculitis / Q000097:blood / Q000276:immunology* / Q000503:physiopathology
D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D015938:Complement Membrane Attack Complex; D037601:Mannose-Binding Lectin; D011414:Properdin; D009195:Peroxidase; D011415:Complement Factor B