Increased vascular leakage and reduced surface CD138 contribute to inflammation-enhanced dissemination. (A) Snapshots from intravital time-lapse images taken before, 2 minutes after, and 2 hours after intravenous administration of Texas Red dextran in the myeloma focus (yellow dashed outline) in the tibia. Insets show dextran leakage in regions within the focus (green) and outside the focus (cyan). (B) Flow cytometric analysis of anti-CD138-PE in vivo labeling of polyclonal normal PCs (nPCs) and myeloma cells (MM) in the tibia BM, with ex vivo co-staining with anti-CD138-APC. (C) Flow cytometric analysis of surface expression of CD138 on myeloma cells with and without in vitro treatment with rTNFα. (D) Comparison of surface expression of CD138 on myeloma cells in the BM of DT-treated or untreated CD169-DTR recipients. Scale bars represent 22 μm. All error bars are standard deviation, with horizontal bars reflecting the mean. *P < .05. APC, allophycocyanin; gMFI, geometric mean fluorescence intensity.