Expression of BAFF and APRIL in the BM environment cells and MMCs. (A) BAFF and APRIL expressions were determined by quantitative PCR in 4 samples of memory B cells, 7 samples of normal plasmablasts, 10 samples of HMCLs, 7 samples of primary MMCs, 7 samples of BM environment cells depleted from MMCs, and 5 samples of BM cells of healthy individuals. (B) BAFF and APRIL expressions were determined by quantitative PCR in purified BM CD3⁺, CD14⁺, or CD15⁺ cells. These cells were obtained from 3 newly diagnosed patients with MM (represented by differently shaded bars). (C) BAFF and APRIL expressions were determined by quantitative PCR in 7 samples of BM stromal cell lines and 7 samples of in vitro–generated osteoclasts. Primary cells were obtained from newly diagnosed patients with MM (represented by differently shaded bars). Dendritic cells (DCs) were used as positive control and assigned the expression value of 100 arbitrary units. (D) BAFF and APRIL concentrations in culture supernatants of BM cells of 10 patients with MM, 7 different BM stromal cell line samples from patients with MM, and 7 different samples of osteoclasts were determined by ELISA.