In vitro expansion of myeloma cells and erythroblasts separately cultured from the bone marrow of patients with MGUS or MM.

(A) A predominant expansion of Fas-L⁺ myeloma clones was observed in plasma cell cultures from patients with stage III MM. Similarly, a prevalent expansion, though to a lower extent, of the Fas⁺ erythroblast subset was recorded in parallel erythroid cultures from these patients (NE indicates not established). (B) Representative cytofluorimetric patterns of CD38⁺bright/Fas-L⁺ and GpA⁺ cell expansion. As compared with those from the MGUS subject, both subsets were largely expanded in the cultures from the MM patient.