Allogeneic haematopoietic stem cell transplantation (HSCT) is commonly used for treating haematological malignancies, immunodeficiencies and inborn errors of metabolism.

The ideal donor for HSCT is an HLA-matched identical sibling, however, only around one third of all patients have access to a suitable sibling donor; mismatched unrelated donors are increasingly used. Alternative graft manipulation strategies for haplo-identical and mismatched related and unrelated grafts are used to reduce the risk of GvHD, these include CD34 Selection and TCR αβ/CD19 depletion. In TCR αβ/CD19 depletion, GvHD causing αβ T cells are depleted while γδ T-cells, which may promote engraftment in allogeneic stem cells, are retained along with natural killer cells (NK cells) that may protect against viruses and the CD34 positive stem cells. In CD34 Selection, stem cells (CD34+ cells) are selected and all T cells are depleted – in order to reduce the occurrence of GvHD.

Some patients with suitable unrelated donors– based on HLA - matching, have un-manipulated apheresis and marrow (referred to as count and issue); the lab simply analyse a sample from the product to calculate CD34 and CD3 (T cells) dose before the product is issued to patients.

Currently data is being collected on patients that have had manipulated graft transplants and other patients that have had un-manipulated grafts with the aim to follow up patients post-transplant to assess the long term immunological outcomes. Patients’ immunology will be assessed at days 30, 60, 90 and 120 post-transplant; these tests: lymphocytes subsets and T-memory cells, T cell panel, regulatory T cells (TREG) and a new assay – T memory stem cell assay will evaluate T cell immune reconstitution.

Results will be collated with patients’ clinical outcomes with regards to the development of GvHD, Infections post-transplant, engraftment and delayed immunity.

Initial results suggest varied immune reconstitution, although hindered by infections.