Maintenance therapy with dose-adjusted 6-mercaptopurine in idiopathic pulmonary hemosiderosis.

There are challenges for diagnosis and treatment of idiopathic pulmonary hemosiderosis (IPH). This clinical trial was to review the diagnosis and evaluate the efficacy of maintenance therapy with dose-adjusted 6-mercaptopurine (6MP) in IPH children. Fifteen children were enrolled. Prednisone was administered at 2 mg/kg/day for 4 weeks in acute phase of the disease followed by taper. 6MP was also started at 60 mg/m(2)/day simultaneously and continued for 3 years in outpatient. The delay in diagnosis of IPH is common and probably due to a lack of classical triad of IPH in most children. All the patients exhibited response to the initial treatment. Only one of eight patients with relative leukopenia on 6MP maintenance recurred while 5 of 7 others recurred (P < 0.05) during median 4.5-year follow-up. Of the latter five patients who recurred, 4 remained recurrence-free after adjusting the dose of 6MP upwards to keep relative leucopenia. It suggests that children with IPH could achieve steroid-free long term remission on 6MP maintenance therapy, and relative leukopenia on 6MP might be a simple maker of predicting clinical response in most IPH children.