Chronic graft versus host disease (cGVHD) is a major cause of nonrelapse morbidity and mortality and occurs in approximately 50% of patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT) (Zeiser et al., 2017). CGVHD is an autoimmune disease in which multiple organs are damaged when immune tolerance is lost. The pathophysiology of cGVHD involves 3 main phases: (1) early inflammation caused by tissue injury, (2) thymic injury and T- and B-cell dysregulation, and (3) tissue repair and fibrosis (Cooke et al., 2017). Currently, cGVHD diagnosis mainly depends on the diagnostic features detailed in the consensus criteria from the National Institutes of Health (NIH), which provide little information for clinical medical decisions (Lee et al., 2015). Thus, specific biomarkers that can improve early diagnosis, predict therapy response, distinguish GVHD from infection- or treatment-related side effects, and aid personalized medicine decisions are urgently needed to increase patient benefit (Ren, H.G, et al., 2018).

Evidence has verified the value of appropriate biomarkers for cGVHD. However, biomarkers or panels with high sensitivity and specificity are lacking. In this review, we discuss the immune cell subgroups, cytokines, chemokines, microRNAs (miRNAs) and autoantibodies that have key roles in cGVHD pathological processes. This review also provides updated knowledge on the relationships between these factors, aiming to broaden their application value and enable clinical application.