Introduction:

Graft-versus-host disease (GVHD) is a complex immune-mediated complication that can occur after allogeneic stem cell transplantation. It is characterized by the activation of donor immune cells (graft) against the recipient's tissues (host), resulting in tissue damage and systemic inflammation. This comprehensive article aims to provide a thorough understanding of graft-versus-host disease, including its types, risk factors, pathophysiology, clinical presentation, diagnosis, and management strategies.

Types of Graft-Versus-Host Disease:

GVHD is categorized into two main types based on the timing of onset and the involvement of different organs:

• Acute GVHD: Acute GVHD typically occurs within the first 100 days after transplantation. It commonly affects the skin, liver, and gastrointestinal tract.
• Chronic GVHD: Chronic GVHD develops beyond 100 days after transplantation. It can affect multiple organs, including the skin, mouth, eyes, lungs, liver, and musculoskeletal system.

Risk Factors and Pathophysiology:

Several factors contribute to the development of GVHD:

• Human leukocyte antigen (HLA) disparity: Greater HLA mismatch between the donor and recipient increases the risk of GVHD.
• Conditioning regimen: The intensity and type of conditioning regimen used prior to transplantation can influence the risk and severity of GVHD.
• Donor type: GVHD risk differs depending on whether the stem cells are obtained from related or unrelated donors or from haploidentical or matched unrelated donors.
• Immunological factors: Variances in the immune response and genetic factors of the donor and recipient contribute to the pathophysiology of GVHD.

The pathophysiology of GVHD involves a complex interplay between the donor's T cells, antigen-presenting cells, cytokines, and the recipient's tissues, leading to an inflammatory cascade and tissue damage.

Clinical Presentation and Diagnosis:

GVHD can manifest with various clinical features depending on the organs affected:

• Acute GVHD: Symptoms may include rash, jaundice, diarrhea, abdominal pain, nausea, and vomiting.
• Chronic GVHD: Symptoms can range from skin changes, dry eyes, mouth ulcers, joint pain, muscle weakness, to liver dysfunction and pulmonary complications.

The diagnosis of GVHD involves a combination of clinical evaluation, histopathological analysis of affected tissues, and exclusion of other potential causes of organ dysfunction or inflammation.

Treatment and Management:

The management of GVHD focuses on suppressing the donor immune response while maintaining graft-versus-leukemia (GVL) effects and preventing infections. Treatment options may include:

• Immunosuppressive therapy: Corticosteroids, such as prednisone or methylprednisolone, are commonly used as the initial treatment for both acute and chronic GVHD. Additional immunosuppressive agents may be added in refractory or severe cases.
• Phototherapy: Ultraviolet (UV) light therapy, such as extracorporeal photopheresis (ECP), can be beneficial in managing chronic GVHD, particularly for skin involvement.
• Supportive care: Symptomatic management, including hydration, nutritional support, pain relief, and infection prevention, is essential for the overall well-being of individuals with GVHD.
• Donor lymphocyte infusion (DLI): In select cases, infusion of donor lymphocytes can be used to enhance the GVL effect and control residual cancer cells.

Conclusion:

Graft-versus-host disease is a complex immune complication that can arise after allogeneic stem cell transplantation. By understanding its types, risk factors, pathophysiology, clinical presentation, diagnosis, and management strategies, healthcare professionals can effectively manage GVHD, minimize complications, and improve the outcomes of individuals undergoing stem cell transplantation.

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