Restricted to hematopoietic cells, LLT1 is not expressed on the surface of resting PBMCs but can be transiently expressed on activated B cells, dendritic cells, T cells, and NK cells (44, 82, 83). Some tumors of hematopoietic origin are also detected by LLT1 expression (75), which is highly expressed by germinal center (GC) B cells and is maintained in the group of non-Hodgkin’s lymphomas that derive from GC B cells (82, 83). The gene discussed is CLEC2D; the disease is non-Hodgkin lymphoma.