In refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS) a discrepancy is observed between the decreased in vitro erythroid colony formation and the normal or increased number of normoblasts in the bone marrow. To study the in vivo and in vitro erythropoiesis in more detail erythron transferrin uptake (ETU), soluble transferrin receptor (sTfR) and erythroid in vitro colony formation were performed in 24 patients with BA and five patients with RARS. These results were correlated with bone marrow morphology and transfusion dependency. Increased (mean, 124.9; range, 74-225 mu mol/l blood/day) and normal (mean, 60.6; range, 50-71) ETU values were observed in 51% and 28% of the cases, whereas 21% of the cases demonstrated a diminished ETU value (mean, 35.8; range, 28-46), which correlated significantly with sTfR in cases with RE (P <0.05, r = 0.64). A significant difference in ETU values was observed between RE (mean, 77.6; range, 28-189) and RARS (mean, 144.0; range, 59-225, P(0.05). Most of the cases (73%) with increased ETU values showed an augmented percentage of erythroblasts in the bone marrow, which was inversely related with the serum Epo levels (P <0.05, r = 0.51). However no correlation was found between the ETU values and the in vitro erythroid colony formation, Transfusion dependency was associated with normal to increased ETU levers (P <0.05) and cytogenetic abnormalities (P <0.05), These observations demonstrate that different patterns of defects can be observed in the erythropoiesis of RA and RARS patients whereby normal to increased ETU levels and the presence of cytogenetic abnormalities differentiate between cases of RE with ineffective erythropoiesis associated with regular transfusions and cases who are relatively transfusion independent.
The predictive value of clinical and platelet kinetic parameters for treatment outcome in idiopathic thrombocytopenic purpura (ITP) was investigated in 75 patients with platelets ≤20 × 109/L. The platelet kinetic studies showed that the platelet production rate (PPR) was decreased (<100 × 109/day), normal, or increased (>355 × 109/day) in 33%, 48%, and 19% of patients, respectively. All patients started with prednisone at diagnosis (1 mg/kg/day). Initial complete and partial response (CR/PR) rate was 84% and a durable CR/PR (≥6 months without treatment) was attained in 44% of the patients. Durable CR/PR was noticed in 64% of the patients with decreased PPR during a median follow-up time without treatment of 81 (range 18–92) months, compared to 34% of the patients with normal or increased PPR during a median follow-up time without treatment of 141 (range 10–284) months (p = 0.03). Splenectomy was performed in 32% of patients with decreased PPR and in 62% of patients with normal or increased PPR (p = 0.03). In conclusion, ITP patients with suppressed PPR have a significant higher durable CR/PR rate to prednisone therapy and are less frequently exposed to splenectomy than those with a normal or increased PPR.
Platelet kinetic studies in idiopathic thrombocytopenic purpura (ITP) have shown that in a subgroup of patients a shortened mean platelet life (MPL) is associated with a decreased platelet production rate (PPR). Other methods of studying certain aspects of thrombocytopoiesis are the plasma concentrations of thrombopoietin and glycocalicin.
