Frequency and kinetics of polyclonal and clonal B cells in the peripheral blood of patients being treated for multiple myeloma

Recent studies concerning the numbers of circulating clonal B cells in pati ents with multiple myeloma (MM) have reported conflicting data regarding th e exact level and phenotype of clonal B cells and their response to treatme nt. In this report we document that the peripheral blood tumor burden at pr esentation was reduced by induction therapy to a low level, regardless of t he initial tumor burden. However, the residual clonal compartment persisted before and after transplant. The level of clonal cells showed no correlati on with CD19(+) cell levels. In a single patient with MM, high numbers of p henotypically aberrant clonal cells with altered CD19 expression were ident ified. (Blood. 2000;96:4357-4359) (C) 2000 by The American Society of Hemat ology.