Tissue Immune Landscape of Graft Versus Host Disease After Allogeneic Stem Cell Transplantation (TIL-GVHD)

Graft versus Host Disease (GVHD) is frequent after allogeneic stem cell transplantation (alloSCT). GVHD occurs following 2 patterns : acute GVHD (aGVHD) or chronic GVHD (cGVHD). The latter occurs in nearly 50% of patients and its pathogenesis remains poorly understood. Previous translational studies have delineated biological immune dysregulation involved in cGVHD and facilitated the development of new drug and therapeutic strategies. New aspects of T and B cells collaboration in the context of cGVHD using blood description of a key player called TFH, classicaly involved in germinal center reaction, were previously uncovered (Forcade et al, Blood 2016). Previous studies in the context of auto-immune inflammation (lupus nephritis) or organ transplant rejection, suggested that target tissue could contain accessory lymphoid structures (TLS). The description of such structures in cGVHD target tissue would give the opportunity to directly analyze immune key player involved the pathogenesis of cGVHD.