Graft-Versus-Host Disease
Graft-versus-host disease (GVHD) is a complex immunological disorder that arises primarily following allogeneic hematopoietic stem cell transplantation (HSCT), wherein immunocompetent donor T lymphocytes recognize and attack recipient antigens, leading to tissue damage. The pathogenesis of GVHD involves a cascade of immune events: initial tissue injury from conditioning regimens releases inflammatory cytokines, activating host antigen-presenting cells (APCs), which in turn stimulate donor T cells. These activated T cells proliferate and differentiate, targeting host tissues such as the skin, liver, and gastrointestinal tract. The subsequent release of additional inflammatory mediators and recruitment of effector cells amplifies tissue injury. GVHD significantly impacts patient health, contributing to morbidity and mortality post-transplant, with manifestations ranging from mild skin rashes to severe multi-organ involvement, chronic immunosuppression, and increased susceptibility to infections and secondary malignancies.
Acute GVHD typically develops within the first 100 days after allogeneic HSCT, but may manifest later in some cases. It is primarily mediated by donor T lymphocytes reacting against host antigens, leading to a rapid-onset inflammatory process. The classic target organs include the skin (presenting as a maculopapular rash), gastrointestinal tract (causing nausea, vomiting, diarrhea, and abdominal pain), and liver (manifested by jaundice and elevated bilirubin). Severity is graded based on the extent of organ involvement and degree of dysfunction, ranging from mild, limited disease to life-threatening multi-organ failure.
Chronic GVHD usually arises after 100 days post-transplant but can overlap with or follow acute GVHD. It is characterized by a broader and more insidious clinical spectrum, often resembling autoimmune or fibrosing disorders. Chronic GVHD may involve the skin (lichen planus-like changes, scleroderma), eyes (dryness, keratoconjunctivitis sicca), mouth (ulcerations, mucositis), lungs (bronchiolitis obliterans), gastrointestinal tract, liver, and other organs. Chronic GVHD is associated with prolonged immunodeficiency, increased risk of infections, and impaired quality of life.
Overlap syndrome refers to the simultaneous presence of both acute and chronic GVHD features in the same patient, typically occurring after day 100 post-transplant. Patients may present with acute manifestations such as rash or gastrointestinal symptoms alongside chronic features like sclerotic skin changes or sicca syndrome. This form often indicates a more severe and treatment-resistant disease course.
GVHD is a major complication of allogeneic hematopoietic stem cell transplantation, affecting approximately 30–50% of recipients, with incidence influenced by factors such as donor-recipient HLA mismatch, donor age, source of stem cells, conditioning regimen, and use of prophylactic immunosuppression. Acute GVHD occurs in up to 50% of patients, whereas chronic GVHD develops in 30–70% of long-term survivors. The risk is higher in unrelated or mismatched donor transplants and with peripheral blood stem cell sources. GVHD remains a leading cause of non-relapse mortality post-transplant, with severe cases resulting in significant morbidity, prolonged hospitalization, and reduced long-term survival. Advances in transplantation techniques and prophylaxis have reduced incidence and severity, but GVHD continues to represent a substantial clinical challenge worldwide.
Diagnosis of GVHD is based on a combination of clinical evaluation, laboratory tests, and histopathological confirmation. Acute GVHD is suspected in patients post-allogeneic HSCT presenting with characteristic symptoms such as skin rash, gastrointestinal disturbances, and liver dysfunction. Clinical grading systems, such as the Glucksberg criteria for acute GVHD and the NIH consensus criteria for chronic GVHD, are used to assess severity and extent of organ involvement. Laboratory investigations may reveal elevated liver enzymes, hyperbilirubinemia, and cytopenias. Biopsies of affected tissues (skin, gastrointestinal mucosa, or liver) are often performed to confirm the diagnosis and exclude other etiologies; histopathology typically demonstrates apoptotic epithelial cells, lymphocytic infiltration, and tissue injury consistent with GVHD. Imaging studies may assist in evaluating organ involvement, particularly in the gastrointestinal tract and lungs. Additional tests, such as chimerism analysis and viral studies, help differentiate GVHD from other post-transplant complications.
Treatment options for graft-versus-host disease encompass a range of immunomodulatory and immunosuppressive agents. Axatilimab, a monoclonal antibody targeting the colony-stimulating factor 1 receptor (CSF1R), is utilized for its role in modulating macrophage activity implicated in GVHD pathogenesis. Belumosudil mesylate, a selective Rho-associated coiled-coil kinase 2 (ROCK2) inhibitor, is indicated for chronic GVHD and functions by regulating inflammatory and fibrotic pathways. Ibrutinib, a Bruton’s tyrosine kinase inhibitor, is also employed in chronic GVHD management, exerting effects on B-cell and T-cell signaling. Remestemcel-L, an allogeneic mesenchymal stem cell therapy, is administered for its immunomodulatory and tissue repair properties, particularly in steroid-refractory acute GVHD. Ruxolitinib phosphate, a Janus kinase (JAK1/JAK2) inhibitor, is approved for both steroid-refractory acute and chronic GVHD, reducing cytokine-mediated inflammation. Abatacept, a fusion protein that inhibits T-cell activation by binding to CD80/CD86, is used to prevent GVHD in certain transplant settings. Mycophenolate mofetil, an antimetabolite immunosuppressant, is incorporated into prophylactic and therapeutic regimens to inhibit lymphocyte proliferation. Tacrolimus, a calcineurin inhibitor, is widely used for both prophylaxis and treatment of GVHD by suppressing T-cell activation. Ciclosporin, another calcineurin inhibitor, serves a similar role in GVHD prophylaxis and therapy. Anti-T-lymphocyte globulin, a polyclonal antibody preparation, is administered to deplete T lymphocytes and mitigate the risk or severity of GVHD, especially in high-risk transplant recipients.
| Structure | Generic Name | CAS Registry Number | Molecular Formula | Molecular Weight |
|---|---|---|---|---|
| axatilimab (Rec INN; USAN); axatilimab-csfr | 2155851-88-8 | |||
 | belumosudil mesylate (Rec INNM; USAN) | 2109704-99-4; 911417-87-3 (free base) | C26 H24 N6 O2 . C H4 O3 S | 548.613 |
 | ibrutinib (Rec INN; USAN) | 936563-96-1 | C25 H24 N6 O2 | 440.497 |
| remestemcel-L (USAN) | 2137084-64-9 | |||
 | ruxolitinib phosphate (Prop INNM; USAN) | 1092939-17-7; 941678-49-5 (free base) | C17 H18 N6 . H3 O4 P | 404.36 |
| abatacept (Rec INN; USAN) | 332348-12-6 | |||
 | mycophenolate mofetil (USAN; BAN) | 128794-94-5 | C23 H31 N O7 | 433.495 |
 | fujimycin; tacrolimus (Rec INN; USAN; BAN) | 104987-11-3 | C44 H69 N O12 | 804.018 |
 | ciclosporin (Rec INN); cyclosporin; cyclosporin A; cyclosporine; cyclosporine A | 59865-13-3 | C62 H111 N11 O12 | 1202.611 |
| anti-T-lymphocyte globulin |
Make Order
Experimental Scheme
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