Abstract Background: Immunoglobulin M nephropathy (IgMN) is a pathological term defining glomerulonephritis with IgM deposition. The clinical significance is still a matter of debate. The aim was to evaluate children with IgM nephropathy (IgMN) in terms of clinical and pathological features, along with treatment responses and outcomes. Materials and Methods: The children with idiopathic nephrotic syndrome (INS) who underwent kidney biopsy at our center (n=41) were evaluated retrospectively. Twenty-one children with IgMN were included. Results: The female to male ratio was 0.9, the median age was 3.5 years in the study group. The mean disease duration and follow-up periods were 11.8 and 11.3years, respectively. At admission, 14% of the patients had hypertension, and 19% had microscopic hematuria. Steroid-dependent nephrotic syndrome (SDNS) was observed in 62% of the patients at admission and 81% at last visit. The patients with IgM (≥2+) depositions had more SDNS than those with IgM (1+). The most common light microscopic diagnosis was mesangial proliferative glomerulonephritis (MesPGN) (47.6%). Focal segmental glomerulosclerosis (FSGS) elevated significantly from 14% at initial biopsy to 57% at follow-up biopsies. Patients who progressed to FSGS mostly had C3 co-deposition, high IgM intensity (≥2+), diagnosis of MesPGN, and SDNS clinic. The most frequently used adjuvant agent was cyclosporine-A (n=19) with mean duration of 68 months. It provided lower relapse rates. Rituximab (n=4) showed 75% remission rate. None of the patients had needed renal replacement treatment. Two patients who were steroid-resistant at admission had FSGS in their first biopsies, acted as multi-drug resistance at follow-up, and ended up in Stage-2 chronic kidney disease (CKD). Conclusion: This study shows IgMN is mainly presented with SDNS clinic and MesPGN pathology. Evolution to FSGS may be related to steroid resistance, MesPGN, high IgM intensity, and C3 co-deposition.
Mutlubaş et al. (Sat,) studied this question.