Transfusion-associated graft-vs-host disease (TA-GVHD) is a rare complication of blood transfusion that is generally fatal for most patients. It can occur when lymphocytes from the transfused blood component attack the recipient’s tissues, and may go unrecognized because the nonspecific symptoms may be attributed to the patient’s underlying diagnosis or another condition such as infection. Although the first cases were reported in immunocompromised patients, it has also been recognized that immunocompetent patients can also develop the condition, especially if the transfused blood components were derived from a human leucocyte antigen (HLA)‐haploidentical unrelated donor or family member.
To date, the clinical and laboratory features of TA‐GVHD, along with the contributions of both recipient and component factors, has not been well defined, and there are no published clinical trials on this condition. Instead, the current evidence for preventing its occurrence is primarily drawn from case reports, hemovigilance data and laboratory methods that attempt to inactivate or eliminate lymphocytes in the transfused components. The current hypothesis is that an individual recipient’s risk will depend on the number and viability of contaminated lymphocytes, the susceptibility of the patient’s immune system to their engraftment, and the degree of immunological (HLA) disparity that exists between donor and recipient. It is unknown what amount of transfused lymphocytes are needed to provoke a GVHD reaction, and this can also vary by clinical setting.
Strategies for preventing TA‐GVHD must address risk factors for the development of the condition, which includes selecting an effective method for inactivating lymphocytes prior to transfusion, appropriate management of the transfusions where HLA haplotypes are likely to be shared between donor and recipient, as well as identifying individuals who are more likely to be susceptible to its development although there are often no identifiable risk factors. As the primary method of inactivating lymphocytes is irradiation, the British Society of Hematology has recently updated their 2012 guidelines on the use of irradiated blood components. The updated guidelines were published in the British Journal of Haematology.
“Irradiation of cellular blood products is performed to prevent transfusion-associated graft-[vs]-host disease,” commented Deva Sharma, MD, MS, transfusion medicine physician and hematologist-oncologist at Vanderbilt University Medical Center in Nashville, Tennessee. “Prior to the advent of irradiated blood products, there was no standardized measure to prevent [TA-GHVD], a nearly fatal complication associated with the transfusion of cellular blood products, which contain T lymphocytes.”
“These viable donor T lymphocytes can target hematopoietic cells and other tissues within the transfusion recipient, leading to multi-organ failure involving the skin, liver and gut and bone marrow aplasia that are characteristic of TA-GVHD,” she said. “The only curative therapy for TA-GHVD is stem cell transplantation.”