Evaluation of therapeutic targeting of CCR7 in acute graft-versus-host disease.

Graft-versus-host disease (GVHD) is the main complication after allogeneic hematopoietic stem cell transplantation. We previously unveiled a correlation between proportions of C-C motif chemokine receptor 7 (CCR7) T cells in the apheresis and the risk of developing GVHD. We wanted to evaluate in vivo whether apheresis with low proportion of CCR7 cells or treatment with an anti-human CCR7 monoclonal antibody (mAb) were suitable strategies to prevent or treat acute GVHD in preclinical xenogeneic models. Therapeutic anti-CCR7 mAb was the most effective strategy in both prophylactic and therapeutic settings where antibody drastically reduced in vivo lymphoid organ infiltration of donor CCR7 T cells, extended lifespan and solved clinical signs. The antibody neutralized in vitro migration of naïve and central memory T cells toward CCR7 ligands and depleted target CCR7 subsets through complement activation. Both mechanisms of action spared CCR7 subsets, including effector memory and effector memory CD45RAT cells which may mediate graft versus leukemia effect and immunity against infections. Accordingly, the numbers of donor CCR7 T cells in the apheresis were not associated to cytomegalovirus reactivation or the recurrence of the underlying disease. These findings provide a promising new strategy to prevent and treat acute GVHD, a condition where new specific, safety and effective treatment is needed.