METHODS: The clinico-pathological features, levels of galactose-deficient IgA1 (Gd-IgA1) and autoantibodies against M-type transmembrane phospholipase A2 receptor (anti-PLA2R) in sera were compared among IgAN-MN, IgAN, and MN patients.
RESULTS: Twenty-six patients with biopsy-proven IgAN-MN were enrolled. The mean age at biopsy was 43.6 ± 15.9 years, and 65.4% were male. Proteinuria and estimated glomerular filtration rate (eGFR) levels in patients with IgAN-MN were similar to that of MN patients. Compared with the IgAN patients, IgAN-MN patients showed a higher median proteinuria level (4.3 vs. 1.2 g/day, p < .001), and a higher mean eGFR level (101.8 ± 25.4 vs. 78.6 ± 26.9 mL/min/1.73 m2, p < .001). IgAN-MN patients presented with milder pathological lesions than IgAN patients according to the Oxford Classification. IgAN-MN patients had comparable serum levels of Gd-IgA1 with those of IgAN patients (353.4 ± 95.5 vs. 347.0 ± 109.6 U/mL, p = .801). Percentage of IgAN-MN patients with detectable serum levels of anti-PLA2R was lower than that of MN patients (38.5% vs. 68.6%, p = .011).
CONCLUSIONS: IgAN-MN patients display similar clinical features to MN patients and milder pathological lesions than IgAN patients. IgAN-MN patients have similar levels of Gd-IgA1 to those of IgAN patients, and a lower proportion of anti-PLA2R than MN patients.