Chronic Graft-versus-host Disease: Immune Insights, Therapeutic Advances, and Parallels for Solid Organ Transplantation

Chronic graft-versus-host disease remains a frequent and morbid outcome of allogeneic hematopoietic cell transplantation, in which the donor-derived immune system attacks healthy recipient tissue. Preceding tissue damage mediated by chemoradiotherapy and alloreactive T cells compromise central and peripheral tolerance mechanisms, leading to aberrant donor T cell and germinal center B cell differentiation, culminating in pathogenic macrophage infiltration and differentiation in a target tissue, with ensuant fibrosis. This process results in a heterogeneous clinical syndrome with significant morbidity and mortality, frequently requiring prolonged therapy. In this review, we discuss the processes that interrupt immune tolerance, the subsequent clinical manifestations, and new Food and Drug Administration-approved therapeutic approaches that have been born from a greater understanding of disease pathogenesis in preclinical systems, linking to parallel processes following solid organ transplantation.