Graft versus host disease

Graft Versus Host Disease

Graft versus host disease (GVHD) is a medical condition that occurs when donor-derived immune cells attack the recipient's tissues following an allogeneic tissue transplant. This condition is most commonly associated with hematopoietic stem cell transplantation (HSCT), but it can also occur in other types of transplants, such as solid organ transplantation.

Pathophysiology

GVHD is initiated when donor T cells recognize the recipient's tissues as foreign. This immune response is primarily mediated by the donor's T lymphocytes, which attack the host's cells. The severity of GVHD can vary, and it is classified into acute and chronic forms based on the timing and nature of the symptoms.

Acute GVHD

Acute GVHD typically occurs within the first 100 days post-transplant. It primarily affects the skin, liver, and gastrointestinal tract. Symptoms may include:

• Skin rash
• Jaundice
• Diarrhea

Chronic GVHD

Chronic GVHD can develop after 100 days and may persist for months or years. It can affect multiple organs and systems, leading to:

• Skin thickening and sclerosis
• Dry eyes and mouth
• Lung fibrosis

Risk Factors

Several factors can increase the risk of developing GVHD, including:

• HLA mismatch between donor and recipient
• Older age of donor or recipient
• Gender mismatch (e.g., male recipient with female donor)
• Intensity of the conditioning regimen

Diagnosis

The diagnosis of GVHD is based on clinical symptoms, laboratory tests, and sometimes biopsy of affected tissues. Differential diagnosis is crucial to distinguish GVHD from other post-transplant complications such as infection or drug toxicity.

Treatment

The primary treatment for GVHD involves immunosuppressive therapy to reduce the activity of the donor immune cells. Common treatments include:

• Corticosteroids (e.g., prednisone)
• Calcineurin inhibitors (e.g., cyclosporine, tacrolimus)
• Monoclonal antibodies (e.g., rituximab)

Prognosis

The prognosis of GVHD varies depending on the severity and response to treatment. Acute GVHD can be life-threatening, while chronic GVHD can lead to long-term disability. Early detection and management are crucial for improving outcomes.

Prevention

Preventive strategies for GVHD include:

• HLA matching between donor and recipient
• Use of immunosuppressive drugs prophylactically
• T-cell depletion of the graft

Also see

• Hematopoietic stem cell transplantation
• Immunosuppression
• Transplant rejection
• Autoimmune disease