Graft versus host disease (GVHD) is the most common complication after allogeneic hematopoietic stem cell transplantation and is an immune response due to donor-derived lymphocytes attacking normal tissues and organs of the patient. Depending on the time of onset and clinical manifestations, it is generally defined as 100 days after transplantation, with those occurring within 100 days referred to as acute GVHD and those occurring after 100 days referred to as chronic GVHD.
Acute GVHD
Acute GVHD is mainly characterized by rash, diarrhea, and jaundice, and is classified as grades I-IV based on the extent of the rash, daily diarrhea, and total bilirubin levels. Among them, acute GVHD of degree III-IV is severe GVHD, and cortisol hormone therapy is preferred, with an efficiency of 40-50%. For hormone-resistant acute GVHD, second-line therapy such as anti-CD25 monoclonal antibodies can be used.
Severe GVHD is less effective, so the emphasis is on prevention, and GVHD prevention often begins in the pretransplant pretreatment phase with anti-thymocyte globulin, calmodulin inhibitors (cyclosporine, tacrolimus, etc.), methotrexate, mortification, and post-transplant cyclophosphamide.
Chronic GVHD
The incidence of chronic GVHD ranges from 30% to 70%, and the presence of chronic GVHD has a graft-versus-tumor effect that reduces the rate of primary recurrence in patients with hematologic malignancies.
Limited chronic GVHD can be treated with topical cortisol hormones.
Patients with severe, widespread chronic GVHD, which greatly affects quality of life and survival, require systemic therapy. The first-line treatment of choice remains cortisol hormones and calmodulin inhibitors; there are many second-line therapeutic agents, with no uniform treatment regimen, and current clinical use includes drugs such as morte-macrolimus, rapamycin, methotrexate, melphalan, mesenchymal stem cell infusion, JAK2 inhibitors, and tyrosine kinase inhibitors.