Clinical and pathological study on patients with primary antineutrophil cytoplasmic autoantibody-associated vasculitis with renal immune complex deposition.

Background: Traditionally, antineutrophil cytoplasmic autoantibody-associated vasculitis (AAV) is histologically characterized by pauci-immune glomerulonephritis. However, more and more literature has reported immune complex (IC) deposits to be found in renal specimen from patients with AAV. The role that these IC deposits play in the development of AAV, as well as their clinical and pathological significance, is worthy of studying.

Objectives: The objective of this study was to analyze the clinical and pathological characteristics of Chinese patients with AAV having renal IC deposition.

Methods: A retrospective study was performed on 34 patients with AAV in Shanghai Ruijin Hospital with renal IC deposition. Clinical and pathological data were collected and studied and compared with other 76 AAV patients having classic pauci-immune glomerulonephritis.

Results: Thirty-four patients were enrolled in this study, with a mean age of 56.4 ± 16.4 years and a male-female ratio of 1:1.3 (19/15). Twenty-seven patients (79.4%) had impaired renal function, with an average serum creatinine of 4.4 ± 3.2 mg/dL. C3 (82.4%) and immunoglobulin M (50%) were the most common IC deposits observed in the kidneys. During the follow-up (median, 39 months), 6 patients (17.7%) died, and 11 (32.4%) finally progressed to end-stage renal disease despite immunosuppressive therapy. Compared with patients having classic pauci-immune glomerulonephritis, patients with renal IC deposits had similar clinical and laboratory features except for more proteinuria (2374 ± 2221 vs 1444 ± 1956 mg/24 h, P = 0.002), a higher prevalence of nephrotic syndrome (30.3% vs 9.6%, P = 0.007) and hypocomplementemia (86.8 ± 33.1 vs 110 ± 45.5 mg/dL, P = 0.029), and also a higher risk for progressing to end-stage renal disease (32.4% vs 13.1%, P = 0.018).

Conclusions: Patients with AAV with renal IC deposition might have a worse renal prognosis than those having classic pauci-immune glomerulonephritis.