Transfusion-associated graft-versus-host disease

Transfusion-Associated Graft-Versus-Host Disease (TA-GVHD) is a rare but often fatal complication that can occur after a blood transfusion. It happens when the immune cells in the transfused blood recognize the recipient's body as foreign and initiate an attack against the host's tissues. This condition is of particular concern in immunocompromised patients, but it can also affect individuals with a normal immune system under certain circumstances.

Causes and Risk Factors

TA-GVHD is caused by the transfusion of lymphocytes, a type of white blood cell, which are capable of engrafting in the recipient and mounting an immune response against the host's tissues. The risk factors for developing TA-GVHD include:

• Transfusion from a donor who is closely related to the recipient and shares certain HLA types (human leukocyte antigen), increasing the likelihood of the donor's lymphocytes engrafting in the recipient.
• Transfusions in which the donor and recipient share HLA haplotypes, even if they are not related.
• Patients with immunodeficiency or those receiving immunosuppressive therapy, making them unable to destroy the transfused lymphocytes.
• Certain medical treatments, such as bone marrow transplantation or therapy for leukemia, which may involve intensive chemotherapy or radiation, leaving the patient more susceptible to TA-GVHD.

Symptoms

The symptoms of TA-GVHD typically develop within 1 to 6 weeks post-transfusion and include:

• Fever
• Rash, often starting on the palms of the hands and soles of the feet and spreading to other parts of the body
• Diarrhea
• Hepatitis
• Bone marrow suppression, leading to anemia, leukopenia (decreased white blood cell count), and thrombocytopenia (decreased platelet count)

Diagnosis

Diagnosis of TA-GVHD involves a combination of clinical assessment and laboratory tests, including:

• Biopsy of affected tissues, showing characteristic histological features
• Blood tests showing pancytopenia (reduction in the number of red and white blood cells and platelets)
• Molecular and immunohistochemical analysis to demonstrate the presence of donor lymphocytes in the recipient's tissues

Prevention and Treatment

Prevention is the most effective strategy against TA-GVHD. Measures include:

• Irradiation of blood products before transfusion to inactivate lymphocytes
• Using leukoreduced blood products, which have a reduced number of white blood cells
• Selecting blood donors who are not closely related to the recipient and do not share HLA haplotypes

Treatment options for TA-GVHD are limited and generally have poor outcomes. They may include:

• Immunosuppressive therapy, such as high-dose corticosteroids
• Supportive care, including management of infections and maintenance of adequate nutrition

Prognosis

The prognosis for patients with TA-GVHD is poor, with mortality rates exceeding 90%. The condition often leads to severe complications, including infections and multi-organ failure.