[Clinical and biological features in refractory anemia with ringed sideroblasts with fluctuant platelet counts]

The objective of this study was to explore the differences between refractory anemia with ringed sideroblast (RARS) and RARS associated with marked thrombocytosis (RARS-T) in the clinical, biological features and prognosis. The morphological changes of cells were observed by bone marrow smear and biopsy. Immunologic phenotype was analyzed by flow cytometry, and chromosome was examined by conventional chromosomal analysis. JAK2 V617F and MPL W515L mutations were screened by allele-specific polymerase chain reaction (AS-PCR) and sequence analysis. The results showed that this case was clinically diagnosed as RARS with thrombophilia, the level of serum potassium was positively related with platelet counts. When platelets increased, the clusters of atypical giant platelets and megakaryocytes were observed in peripheral blood and bone marrow examined by bone marrow smear and bone marrow biopsy respectively, JAK2 V617F and MPL W515L mutations were negative. It is concluded that RARS may transform into RARS-T accompanied with megakaryocyte proliferation, large atypical platelets and negative JAK2 V617F. Preventing thrombophilia and monitoring relative gene mutations are necessary when atypical giant platelets and fluctuant platelet counts occurred in process of RARS with tendency to RARS-T.