[Clinicopathologic analysis of 34 patients with microscopic polyangitis].
OBJECTIVE
To study the clinicopathologic features of microscopic polyangitis (MPA), and to compare the differences in anti-neutrophil cytoplasmic autoantibody (ANCA)-positive and ANCA-negative patients, as well as in ANCA-positive cases with or without glomerular immunoglobulin deposition.


METHODS
Thirty-four biopsy-proven cases of MPA were retrieved from the archival files of the Department during the past 7 years. The clinicopathologic characteristics between ANCA-positive and negative patients, as well as between ANCA-positive cases with and without glomerular immunoglobulin deposition, were compared.


RESULTS
Amongst the 34 MPA patients studied, about one-fifth to one-half were accompanied by various extrarenal symptoms. Serum ANCA was positive in 26 patients (76.5%). A slight to moderate increase in urinary protein was demonstrated in 31 patients, while 3 patients had nephrotic syndrome. Elevated serum creatinine was detected in 32 cases. Renal biopsy revealed crescentic glomerulonephritis in 24 cases, focal segmental glomerulonephritis in 8 cases, vascular fibrinoid necrosis with inflammation in 7 cases, intimal thickening of arterioles in 24 cases, interstitial inflammatory cells, including neutrophil infiltration (21 cases), in 29 cases. Crescentic formation was more common in the ANCA-positive group than in the ANCA-negative group (P < 0.05). Amongst the 26 ANCA-positive cases, 10 had glomerular immunoglobulin deposits (including 1 case with IgA nephropathy). In general, these cases had a greater degree of proteinuria than those without glomerular immunoglobulin deposits (P < 0.05).


CONCLUSIONS
The diagnosis of MPA relies on histologic examination of renal biopsy and clinicopathologic correlation. Serum ANCA seems important for glomerular crescent formation. Glomerular immunoglobulin deposition may also play a significant role in the exacerbation of proteinuria.
Xuan
Xian-fa
XF
Department of Pathology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
Wu
Hui-juan
HJ
Liu
Ye
Y
Zhao
Zhong-hua
ZH
Hong
Feng-ying
FY
Wang
Yu-xin
YX
Zhang
Zhi-gang
ZG
Guo
Mu-yi
MY
D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000378:metabolism*; D015415:Biomarkers; D001706:Biopsy; D005260:Female; D005921:Glomerulonephritis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000378:metabolism; D007668:Kidney / Q000473:pathology*; D007674:Kidney Diseases / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009404:Nephrotic Syndrome / Q000378:metabolism / Q000473:pathology; D011507:Proteinuria / Q000473:pathology; D012189:Retrospective Studies; D014657:Vasculitis / Q000378:metabolism / Q000473:pathology*
D019268:Antibodies, Antineutrophil Cytoplasmic; D015415:Biomarkers; D007132:Immunoglobulin Isotypes