TIGIT and plasma cell myeloma: Our present study showed that T cells in PBSC grafts—both from healthy donors and patients with lymphoma or multiple myeloma—expressed variable levels of inhibitory receptors PD-1, CTLA-4, TIM-3, LAG-3, TIGIT and BTLA on their surface, with T cells in autografts expressing a higher level of these inhibitory receptors (Figure 2).