Evaluation of a Donor Testing Kit for the Prediction of AGVHD in Patient Receiving a Peripheral Blood Stem Cell Allograft

Acute Graft Versus Host Disease (aGVHD) is the most frequent complication in allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT). It affects up to 50% patients, among whom 15% to 25% develop severe forms, often lethal, yet impossible to predict even for donors with a Human Leukocyte Antigene (HLA) 10/10 compatibility. Global Overall Survival (OS) after transplantation is 40% to 60% only due to post transplant severe complications. There is a major medical need for a technology that would predict the risk of aGVHD and would allow the selection of a favourable donor among multiple Human Leukocyte Antigene (HLA)10/10 compatible donors.

MT. Rubio and M. Bouillié at Pr Olivier Hermine's lab previously reported that enhanced early post-transplant invariant Natural Killer T (iNKT) cells reconstitution from donor cells was correlated to reduced risk of aGVHD, without impairment of the Graft Versus Leukemia (GVL) effect. They subsequently demonstrated that the expansion of donors CD4neg invariant Natural Killer T (iNKT) cells subpopulation was predictive of a reduced risk of aGVHD, and developed a method for predicting this risk based on the expansion factor of CD4neg invariant Natural Killer T (iNKT) cells in the peripheral blood stem cell (PBSC) graft. This invariant Natural Killer T (iNKT) cells functional test reaches its optimal predictive capacity with 94% sensitivity and 100% specificity in allo-HSCT performed with Human Leukocyte Antigene (HLA) 10/10 matched peripheral blood stem cell (PBSC) grafts for non-progressive hematological malignant diseases, in complete response, which represent the majority of the indications of allogeneic HSCT. Similar predictive value was also observed when the test was performed from donor's peripheral blood before G-CSF mobilization. It was not associated with an increased risk of relapse. This test could therefore allow to easily selecting the best donor if different siblings or unrelated donors are available before PBSC allo-HSCT.