TNFRSF17 and hematologic disorder: Success in hematological malignancies has several causes: (i) contacts between malignant cells and T cells are probably not limited; (ii) targeted malignant B cells often co-express costimulatory ligands; (iii) targets such as CD19, CD20 or BCMA are lineage-specific and not found on other cell types and are expressed homogenously and at bright levels.