[Effect of mechlorethamine in idiopathic nephrotic syndrome in childhood]

Mechlorethamine has been assessed in 28 patients with idiopathic nephrotic syndrome previously treated with prednisone only. One patient was cortico-resistant (CR), 22 cortico-dependent (CD) and 5 patients had frequent relapses (FR). FR patients had not histological examination and CR patient had a global focal sclerosis (GFS). Among CD patients, 12 had minimal change nephropathy (MCN) and 10 had a diffuse mesangial proliferation (DMP). After prednisone treatment was started, 0.1 mg/kg/d of mechlorethamine for four days was administered iv, in hospital and repeated one month later. After mechlorethamine treatment, GFS evolution was unchanged. Among FR, all the patients improved, 3 with complete remission and 2 with infrequent relapses. MNC improved in 66.6% and DMP in 40%, with the best evolution in immunofluorescence negative patients. Among early side effects, we found gastrointestinal disorders in 11 cases (39.2%) and leukopenia in 8 (28.2%), that required discontinuation of treatment in only 2 cases. We have not assessed gonadal toxicity. We comment the evolution after treatment of the different histological patterns, comparing with other nitrogen mustards and we conclude that mechlorethamine is useful in FR and CD idiopathic nephrotic syndrome corresponding to MCN or DMP with negative inmunofluorescence. Results with other nitrogen mustards, especially chlorambucil, are better.