OBJECTIVETo study the significance of trace immunoglobulin M (IgM) deposits in glomerular mesangium in children with minimal change primary nephrotic syndrome (PNS).

METHODSOne hundred and six children who were clinically diagnosed with PNS and pathologically diagnosed with minimal change disease (MCD) and trace deposition of IgM in renal tissues were enrolled as subjects. Eighty-one PNS children with MCD but no deposition of immune complexes were used as the control group. The clinical characteristics and efficacies of glucocorticoids and immunosuppressants were retrospectively analyzed in the two groups. All patients were given full-dose prednisone by oral administration, and patients with glucocorticoid resistance or frequent relapses were additionally given immunosuppressants.

RESULTSThe incidence of glucocorticoid resistance in the IgM deposit group was significantly higher than that in the control group (27.2% vs 12.3%; P<0.05). The incidence of frequent relapses in the IgM deposit group was also significantly higher than that in the control group (48.1% vs 10.4%; P<0.05). The complete remission rate for glucocorticoid-resistant patients treated with prednisone combined with mycophenolate mofetil (MMF) was 68% and 62% respectively in the IgM deposit and control groups (P>0.05). The relapse frequency in patients with frequent relapses was significantly reduced in both groups after treatment with prednisone and MMF in combination (P<0.05).

CONCLUSIONSTrace deposition of IgM in renal tissues may be an important factor for glucocorticoid resistance and frequent relapses in PNS children with MCD. Prednisone combined with MMF may be a better choice in the treatment of patients with glucocorticoid resistance or frequent relapses.