Impact of GVHD on lymphoma progression: Nationwide study from Japanese Society for Transplantation and Cellular Therapy.

Summary: The graft‐versus‐lymphoma (GVL) effect and its association with acute and chronic GVHD (aGVHD, cGVHD) has not been comprehensively elucidated. We retrospectively analysed 2204 Japanese patients with non‐Hodgkin lymphomas (NHLs; indolent B‐NHLs, n = 689; aggressive B‐NHLs, n = 720; mature T/NK‐NHLs, n = 795) receiving a first allo‐HSCT in 2003–2017. Pre‐transplant lymphoma control showed complete response (CR) in 759 and non‐CR in 1445. We assessed the impact of aGVHD/cGVHD on lymphoma progression and other outcomes. Although aGVHD/cGVHD showed no statistical impact on lymphoma progression in the overall cohort, their impact was clear in certain groups: Grade I‐II aGVHD in CR patients (HR, 0.63; 95% CI, 0.43–0.91), especially in mature T/NK‐NHL (HR, 0.46; 95% CI, 0.26–0.83) and extensive cGVHD in patients with mature aggressive B‐NHLs (HR, 0.55; 95% CI, 0.31–0.97). In total, limited cGVHD was associated with superior survivals (progression‐free survival: HR, 0.71; 95% CI, 0.56–0.90), whereas severe GVHDs showed negative impacts on them. Our results support the presence of GVL effects differentially associated with GVHD in different lymphoma subtypes/controls. Meanwhile, it was also suggested that we should manage GVHDs within a limited activity, considering the negative impact of severe GVHDs. As pre‐transplant lymphoma control remains a strong factor influencing transplant outcomes, improving its management is an important issue to be addressed. [ABSTRACT FROM AUTHOR]