Clinical value of systemic symptoms in IgA nephropathy with ANCA positivity

Our aim was to evaluate the pathogenic role of anti-neutrophil cytoplasmic antibodies (ANCAs) in patients with IgA nephropathy (IgAN). A total of 2390 patients with biopsy-confirmed IgAN were analyzed retrospectively. Thirty-five IgAN patients with ANCA and 40 IgAN patients without ANCA were enrolled. According to the Birmingham Vasculitis Activity Score (BVAS) items, the ANCA-positive patients were further divided into two subgroups which with or without systemic symptoms. The cumulative renal survival rate was calculated using Kaplan–Meier analysis. Comparisons between groups were made using the log rank test. Among the 35 ANCA-positive patients, 14 (40%) had systemic symptoms. Compared with ANCA-positive patients without systemic symptoms, ANCA-positive patients with systemic symptoms had a shorter duration of disease (1.0 [IQR, 0.3–6.8] vs. 6.0 [IQR, 2.0–21.0], P = 0.011); showed worse renal function with lower levels of eGFR (24.2 [IQR, 11.7–74.9] vs. 100.1 [IQR, 59.6–130.2] mL/min/1.73 m 2 , P = 0.002), serum albumin (30.4 [IQR, 27.4–34.8] vs. 41.5 [IQR, 35.1–44.4] g/L, P = 0.001), and hemoglobin (96.1 ± 21.5 vs. 118.2 ± 22.4 g/L, P = 0.006); and presented relatively higher incidences of rapidly deteriorating kidney function (28.6 vs. 0.0%, P = 0.039) and moderate-to-severe tubular atrophy (78.6 vs. 23.8%, P = 0.001). Kaplan–Meier analysis had shown that ANCA-positive patients with systemic symptoms had lower cumulative renal survival rate compared with both ANCA-positive patients without systemic symptoms and ANCA-negative patients (log rank = 14.40, P < 0.001). Evaluation of systemic symptoms is a simple, readily available clinical tool to predictive the pathogenic role of ANCA in IgAN.