RECONSTITUTION OF T-CELL-MEDIATED IMMUNITY IN PATIENTS AFTER ALLOGENEIC STEM CELL TRANSPLANTATION

Background. The timely reconstitution of the donor-derived immune system is a key factor in the prevention of such post-transplant complications as graft versus host disease, relapse or secondary tumours and various infections. These complications affect the long-term survival of patients after allogeneic stem cell transplantation. Aim - to describe the main stages of T Cell-mediated immune recovery in patients after allogeneic stem cell transplantation. General findings. T-cell-mediated immunity is responsible for anti-infective and anti-tumour immune response. The early post-transplant period is characterized by the thymus-independent pathway of T-cell recovery largely involving proliferation of mature donor T cells, which were transplanted to the patient together with hematopoietic stem cells. To a lesser extent, this recovery pathway is realized through the expansion of host naive and memory T cells, which survived after conditioning. Thymus-dependent reconstitution involves generation of de novo naive T cells and subsequent formation of a pool of memory T-cells providing the main immunological effects - graft versus tumour and graft versus host reactions. A better understanding of the T-cell immune reconstitution process is important for selecting optimized pre-transplant conditioning regimens and patient-specific immunosuppressive therapy approaches, thus reducing the risks of post-transplant complications and improving the long-term survival of patients after allogeneic stem cell transplantation.