IgA nephropathy with anti-neutrophil cytoplasmic antibody seropositivity.

BACKGROUND: There are few reports of IgA nephropathy (IgAN) with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis. METHODS: The authors report the clinical and pathological findings in 14 patients with IgAN and ANCA seropositivity. RESULTS: These retrospective cases consisted of 4 men and 10 women with a mean age of 44.4 ± 12.7 years. ANCA-positivity was documented by EUROBlot kits and indirect immunofluorescence in all patients. The results of EUROBlot kits were positive in 14 patients (12 MPO-ANCA, 2 PR3-ANCA). Indirect immunofluorescence was positive in 14 patients (12 P-ANCA, 2 C-ANCA). Three of 14 IgAN with ANCA-positive patients showed severe clinical manifestations with crescents involving a mean of 56% glomeruli, including heavy proteinuria (mean 24-hour urine protein: 3.8 g/d), hematuria and acute renal failure (mean creatinine: 4.5 ± 3.7 mg/dL). The remaining 11 patients with no crescents showed various degrees of proteinuria (mean 24-hour urine protein: 2.4 ± 2.4 g/d), hematuria and serum creatinine levels (median creatinine: 0.9 (IQR, 0.5 - 1.4) mg/dL). The follow-up period for 10 patients had an average length of 14.0 ± 11.2 months. Among the three patients with crescents who had been treated with steroids and cyclophosphamide, one patient became dialysis dependent at the time of biopsy and remained on dialysis after treatment, another died of acute heart failure, and the last one showed improvement in renal function after treatment and did not develop end-stage renal disease (ESRD) 26 months after renal biopsy. The remaining 7 patients with no crescents were treated with steroids, cyclophosphamide, renin-angiotensin system inhibitors, and/or Traditional Chinese Medicine; 6 had stabilized or improved renal function and one progressed to ESRD with worsening renal function. CONCLUSIONS: These findings suggest not all ANCAs are involved in the pathology of IgAN. In patients with IgAN and ANCAs, identification of pathogenic vs. non-pathogenic ANCAs is recommended.