Reactive plasmacytoses in multiple myeloma during hematopoietic recovery with G- or GM-CSF

We report on three cases of reactive plasmacytoses (RP) in the course of mu ltiple myeloma (MM). The three patients achieved complete remission followi ng high dose melphalan and peripheral blood stem cell transplantation. Thes e transient plasmacytoses had all the characteristics of RP, i.e. expansion of highly proliferative polyclonal plasma cells (PC) with a normal phenoty pe and genotype and corresponding to expansion of both PC progenitors (plas mablasts) and PC precursors (early plasma cells). These cells were easily d istinguished from malignant PC of the corresponding patients evaluated at d iagnosis, especially by their phenotypic and genotypic features. (C) 2000 E lsevier Science Ltd. All rights reserved.