Interleukin-22 modulating properties in graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy used to treat hematologic malignancies. The number of allo-HSCT is constantly increasing because of the development of reduced intensity conditioning. Graft-versus-host disease (GVHD) is still the major complication after allogeneic stem cell transplantation. GVHD results from the activation of the immune response and the recognition by donor T cells of alloantigens leading to tissue injury, especially in skin, gut and liver. Interleukin-22 (IL-22) is a cytokine secreted by CD4+ T cells Th1 and Th17 but also by innate lymphoid cells (ILC). IL-22 presents both regenerative and proinflammatory effects. Its role in GVHD seems to depend on its origin (donor/host), the timing and the cytokinic environment. After discussing of the main properties of IL-22, this review presents IL-22 main effects in allo-HSCT and more particularly in GVHD.