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.
Patient > 18 yo ;
Having undergone an allogeneic stem cell tranplant ;
2 groups of patients will be eligible
showing evidence of primary cGVHD or occuring after Donor Lymphocyte Infusion
Patient below 18 yo or unable to give consent ;
Systemic therapy using steroids over 15mg/d of Prednisone ; and/or the use of other systemic agent introduced in the last month ;
Haemorrhagic risk of biopsy anticipated ;
Absence of patient agreement for the study