The role of CD169+ subcapsular sinus macrophages is to act as gatekeepers for soluble, lymph-borne, particulate antigens (virus, bacteria or tumor antigens), to deliver antigens to activate B cells present in the lymphoid follicles, and they are also assigned as crucial antigen-presenting cells (APCs) for high-affinity B cell responses (15, 16). The gene discussed is SIGLEC1; the disease is neoplasm.