[Incidental mesangial IgA deposition in minimal change nephrotic syndrome(MCNS)].

The frequency of incidental mesangial IgA deposition and its clinicopathological features were investigated in patients with minimal change nephrotic syndrome(MCNS). Mesangial IgA deposition was present in 15/63 patients(23.8%), and co-deposition of IgA and C3 was present in 10/63 patients(15.9%). The serum IgA concentration was significantly higher in IgA(+) patients than in IgA(-) patients(341 +/- 79 mg/dl vs. 252 +/- 99 mg/dl, p = 0.034). The urinary red blood cell count tended to be higher in IgA(+) patients than in IgA(-) patients (12.8 +/- 24.9 vs. 5.0 +/- 7.9 counts/HPF, p = 0.58). Histologically, no significant differences were observed between IgA(+) and IgA(-) patients. After steroid treatment. 14 patients with mesangial IgA deposition showed complete remission and one patient had persistent proteinuria. The microhematuria also disappeared after steroid treatment in 13/15 patients (86.7%), although it reappeared in 6/13 patients(46%) during reduction of steroid administration. The present study indicated that the incidental mesangial IgA deposition was frequently observed in MCNS patients(23.8%). The phenomenon of mesangial IgA deposition was related to the higher concentration of serum IgA. However, no influence of mesangial IgA deposition in MCNS patients was found on the post-treatment amount of proteinuria, renal function and clinical outcome of MCNS.