Abstract 13

About 50% of patients with DBA do not remain in stable remission under GCC therapy and are transfusion dependent. We report an 11 year old male with DBA and selective IgG2 deficiency. He responded only shortly to initial GCC therapy and necessitated a regular transfusion regime every 2-3 weeks since the age of 8 years. GCC was stopped. Two years later he had considerable hemosiderosis (ferritin 2.187 ng/ml, liver density: 110HE) with mild cardiomyopathy. He was referred to our hospital for continuous desferal therapy. Bone marrow aspiration showed a lack of erythropoiesis without any further anomalies. In vitro stem cell culture showed a threefold increase of erythroid colonies by addition of hydro-cortison and further increase with interleukin 3 and SCF. Upon prednisolon (2 mg/kg) the patient showed a short reticulocytosis (10,6% at day 16 of treatment; 0% at day 35). A second course of i.v. GCC gave no rise of reticulocytes: at that time the stem cell culture showed an increase of erythropoiesis with SCF but not with GCC or interleukin 3. After informed consent we applied SCF (30 mg/kg daily s.c.) together with prednisolon (2 mg/kg). Reticulocytes raised to 8,8% on day 39 with a stable hemoglobin value over 40 days but declined again to 0% one week later and transfusion was again necessary. Sideeffects of SCF therapy were extensive local edema, respiratory obstruction, fever and temporary increase of GPT, gGT and LDH. Therapy was ended. In conclusion it seems that GCC therapy led to maturation of only determined erythropoietic progenitor cells. SCF seems to augment and induce maturation of more immature stem cells but was not able to sustain a stable remission.