Clinical and Histological Characteristics in Patients with Non-IgA Mesangioproliferative Glomerulonephritis

Background: Mesangioproliferative glomerulonephritis is the most common type of chronic glomerulonephritis (CGN). However, the clinical characteristics and prognosis are not fully understood in patients without Immunoglobulin A (IgA) deposition. To explore the clinical and pathological characteristics of patients with mesangioproliferative glomerulonephritis without IgA deposition (N-IgAN), we performed dual retrospective analyses. Methods: A single-center study was performed in 60 patients with biopsy-proven N-IgAN. 98 ageand sex-matched IgA nephropathy (IgAN) patients were randomly selected as a control group. The clinical and histopathological data at the time of renal biopsy were compared between N-IgAN and IgAN. In a second study, the data for 477 patients who had undergone maintenance renal replacement therapy (RRT) was collected and examined for the causal primary diseases. Results: Duration from onset of renal symptoms to renal biopsy in patients with N-IgAN (71.2 ± 123.3 months) was significantly longer than that in patients with IgAN (65.9±74.9 months) (p=0.0328). Urinary protein excretion in N-IgAN patients (0.6±1.1 g/gCr) was significantly lower than that in IgAN (1.0 ± 1.3 g/gCr) (p < 0.0001). Ratio of global sclerosis, segmental sclerosis, crescents, interstitial mononuclear cell infiltration, interstitial fibrosis, and tubular atrophy were significantly lower in N-IgAN patients. Of the 477 patients who had undergone maintenance RRT, 95 patients had CGN (19.9%). Among them, 37 patients had received a renal biopsy, only one patient was N-IgAN (1%). Conclusion: It appears that N-IgAN can be recognized as a benign disease entity in comparison with IgAN.