Dysregulation of CD47 and the ligands thrombospondin 1 and 2 in multiple myeloma

Summary CD47 and thrombospondin 1 and 2 (TSP1 and TSP2) expression were analysed by real‐time reverse transcription polymerase chain reaction in fluorescence‐activated cell sorted plasma cells (PCs) from patients at consecutive stages of multiple myeloma (MM) development. 80% of MM patients, but only 39% of patients with monoclonal gammopathy of undetermined significance (MGUS) expressed CD47 ; median expression level increased 10‐fold with progression from MGUS to MM. Elevated TSP1/TSP2 levels occurred in bone marrow cultures from MM patients compared with healthy donors. CD47 and TSP1/TSP2 may have a potential role in the pathophysiology of MM, probably in the interaction between MM PCs and the microenvironment.