Effective therapy of a child case of refractory nephrotic syndrome with tacrolimus

We report here the case of a 9-year-old Japanese boy with nephrotic syndrome caused by focal segmental glomerulosclerosis, which was refractory to treatment. Although aggressive immunosuppressive therapy consisting of methylprednisolone pulse therapy combined with cyclosporine A (CsA) and intermittent low density lipoprotein apheresis was effective in overcoming his steroid-resistant state, the child became persistently steroid-dependent, that is, more than 0.75 mg/kg per day of prednisolone combined with CsA was required to maintain a negative test for proteinuria. Since adverse effects of prednisolone, such as short stature, obesity, osteoporosis and cataract, were noted, CsA in his treatment regimen was replaced with tacrolimus at the dose of 0.1 mg/kg per day, with the trough blood level of the drug maintained at around 10 ng/ml. Within 4 months of the inclusion of tacrolimus in the treatment regimen, complete remission was achieved, with no recurrence of the proteinuria, while the prednisolone dose could be tapered to 0.3 mg/kg per day. No adverse effects of tacrolimus were observed. These clinical results suggest that tacrolimus may be the drug of choice in selected patients with refractory nephrotic syndrome, even if pediatric-onset cases, at least those in whom the steroid-sparing effects of CsA is unsatisfactory.