Mycophenolate mofetil therapy for steroid-resistant IgA nephropathy with the nephrotic syndrome in children

Immunoglobulin A nephropathy (IgAN) presents as nephrotic syndrome (NS) relatively rarely, and the current treatment experience of IgAN patients with NS is mostly with adults. The objective of our study was to investigate the efficacy of corticosteroids and mycophenolate mofetil (MMF) in treating childhood immunoglobulin A nephropathy (IgAN) with nephrotic syndrome.

A total of 58 children (39 boys and 19 girls) diagnosed with nephrotic syndrome and primary IgAN were enrolled in the study. All the patients were administered prednisone 2 mg/kg per day for 8 weeks. Steroid-resistant patients were treated with the combined use of MMF (dose of 20 ~ 30 mg/kg per day) and prednisone for 6-12 months. The prednisone dose was reduced stepwise during the combined treatment.

Of the 58 children, 14 were steroid-sensitive (M, S, and T variants of the Oxford classification were 0 in most children), and 44 cases who presented serious pathological damage to the kidney were steroid-resistant. The estimated glomerular filtration rate (eGFR) of the steroid-resistant children (86.69 ± 26.85 ml/min/1.73 m(2)) was significantly lower (P < 0.05) than that of the steroid-sensitive children (106.89 ± 26.94 ml/min/1.73 m(2)). After 4 months of combined MMF treatment in 33 steroid-resistant children, complete remission of proteinuria was found in 21 cases, partial remission of proteinuria in 6 cases, and no response was found in 6 cases. Except for the T variant, other variants of the Oxford classification, including M, E, and S morphological variables, was not significantly different among patients complete remission, those with partial remission, and those with no response. The eGFR of children with complete remission of proteinuria (100.04 ± 18.47 ml/min/1.73 m(2)), that of those with partial remission (92.24 ± 27.63 ml/min/1.73 m(2)), and that of those with no response (72.17 ± 27.55 ml/min/1.73 m(2)) were significantly different (P < 0.05).

Corticosteroid therapy showed satisfactory efficacy in IgAN children with nephrotic syndrome and slight pathological damage. The effect of MMF was good for steroid-resistant IgAN children, but poor for those with tubular atrophy/interstitial fibrosis and renal function impairment.