CD27 is heterogeneously expressed in multiple myeloma: low CD27 expression in patients with high-risk disease.

Expression of CD27 on malignant plasma cells (PC) (CD138+CD38++) was analysed in a cross-sectional study of bone marrow (BM) samples from multiple myeloma (MM) patients (n = 28), monoclonal gammopathy of undetermined significance (MGUS) patients (n = 6) and BM PC from healthy donors (n = 4). MM PC expressed CD27 with a variable, lower intensity pattern compared with the consistent high expression in MGUS and healthy donors. MM patients in complete clinical remission displayed a higher percentage of CD27+ PC compared with patients at diagnosis, relapse or in partial remission.