Fig. 7

CXCL13 expression and flow cytometry analysis in primary MM samples. A CXCL13 levels in peripheral blood of MM patients with active disease (n = 32), stable disease (n = 29), or in healthy donors (n = 9), evaluated by ELISA. B CXCL13 levels in BM plasma samples of MM patients (n = 36) and healthy donors (n = 6), evaluated by ELISA. Data are presented as mean ± STDEV, **p < 0.01. C Flow cytometry analysis of cells in normal BM samples (n = 6) and MM BM samples (n = 20). The cells were pre-gated on CD11b+ CD14+ population. The frequency of RANK+ CD51+ cells, MERTK+ cells and CD163+ CD206+ was established (upper panel). The frequency of CD14+ CD16− and CD14+ CD16+ subpopulations, and percentage of MERTK+ cells in both subsets are presented (lower panel). D (i) Spearman’s rho correlation (two-tailed) between the frequency of CD163+ CD206+ and the frequency of RANK+ CD51+ subsets on CD11b+ CD14+ cells in BM samples (normal BM, n = 6; MM BM, n = 20). (ii) Spearman’s rho correlation (two-tailed) between the expression of MERTK and the co-expression of RANK and CD51 on CD11b+ CD14+ cells in BM samples (normal BM, n = 6; MM BM, n = 20). (iii) Spearman’s rho correlation (two-tailed) between CXCL13 protein levels in BM plasma and the frequency of MERTK expression on CD11b+ CD14+ cells in BM samples (normal BM, n = 6; MM BM, n = 20). E Expression of CXCL13 in normal BM samples, BM samples from patients with MM, and plasmacytoma samples, evaluated by immunohistochemical staining. Original magnification of × 400 is shown