Immune Monitoring After Allogeneic Hematopoietic Stem Cell Transplantation

Graft versus Host disease ( GVHD) is one of the major complications of Allogeneic Stem Cell Transplantation. Acute GVHD develops early ( within 2to 3 months) after transplantation and is the leading cause of death of transplanted patients. The pathogenesis of Chronic GVHD is still little known. Chronic GVHD is caused by donor T lymphocytes, but we have no precise knowledge on the participation of specific subsets of immune system cells to chronic GVHD. In general, chronic GVHD is associated with an increase in the number of T effector lymphocytes, both helper type 2 and cytotoxic. Recently, also antigen presenting cells (APCs) have been implicated in pathogenesis of chronic GVHD in studies performed on animal models. T lymphocyte responses that characterize chronic GVHD require that recipient antigens are submitted by APCs which originate from the donor's HSC ( Hematopoietic Stem Cells) APCs are heterogeneous population that includes dendritic cells (DCs) ,monocytes, activated B lymphocytes and CD34+ cell subpopulations. These cells can be identified by cytometry. The data about APCs role in chronic GVHD are preliminary and often discordant. Seemingly, there isn't correlation between circulating APCs number and risk of cGVHD. However, recent data of our group show that patients with cGVHD could have higher number of monocytes in bone marrow than transplanted patients without cGVHD. The aim of study is to measure the number of circulating immune cells in the PB (peripherical blood) before and after Allogeneic Hematopoietic Stem Cell Transplantation by flow cytometry.