Myelodysplasia-associated immunophenotypic alterations of bone marrow cells in myeloma: are they present at diagnosis or are they induced by lenalidomide?

Increased risk of acute myeloid leukemia/myelodysplastic syndromes following treatment has been reported in multiple myeloma, but whether dysplastic features are already present at diagnosis remains to be investigated. Using multiparameter flow cytometry, we analyzed the distribution and phenotype of bone marrow hematopoietic cells from 47 multiple myeloma patients (15 symptomatic and 32 high-risk smoldering). From the 32 smoldering myeloma patients, 18 were studied at baseline and 22 after nine cycles of lenalidomide/dexamethasone treatment following the QUIREDEX trial (including 8 from baseline). Phenotypic alterations of bone marrow cells of 7 (47%) symptomatic and 6 (33%) smoldering myeloma patients were detected at baseline; there was no difference in the frequency and extent of phenotypic alterations between symptomatic versus smoldering cases. Likewise, no difference was seen between smoldering myeloma patients studied at baseline versus after lenalidomide/dexamethasone treatment. Our results suggest that phenotypic alterations of bone marrow hematopoietic cells are often present in newly diagnosed symptomatic and smoldering multiple myeloma patients. QUIREDEX trial (NCT00480363).