Irradiation of Blood Products

Indications

Table 42.1 lists the clear indications, the indications deemed appropriate by most authorities, and the indications considered unwarranted by most authorities for irradiated blood products. Even in centers of excellence, some divergence of opinions about indications for irradiation does occur, so each transfusion service should develop its own criteria and indications in concert with ordering physicians.

Guidelines and Standards for Irradiation and Mitigation of Transfusion-Associated Graft-Versus-Host Disease

AABB Standard 5.19.3 states:

The BB/TS (blood bank/transfusion service) shall have a policy regarding the transfusion of irradiated components. At a minimum cellular components shall be irradiated when: 1) A patient is identified as being at risk for TA-GVHD; 2) The donor of the component is a blood relative of the recipient; 3) The donor is selected for HLA compatibility, by typing or crossmatching.

The United States currently does not have established or widely adopted guidelines or indications for irradiation of blood components. Therefore, indications vary from institution to institution, and there is heterogeneity of practice. Results of a survey performed by the College of American Pathologists in 2014 demonstrated that 78.6% of institutions provided irradiated components for patients who were receiving products from blood relatives, 68.9% for patients receiving HLA-matched or partially matched products, 66.3% for neonatal exchange transfusions, 63.3% for intrauterine transfusions (IUTs), 62.7% for allogeneic/autologous hematopoietic progenitor cell transplant, and 61.8% for preterm/low-birth-weight infants. These data demonstrate that even for indications that AABB deems irradiation should be performed (e.g., transfusions that are HLA-matched or from blood relatives), there is variation in practice.

Universal Irradiation

Several factors related to TA-GVHD and irradiation lead to the adoption of universal irradiation in some centers and countries:

• 1.

  TA-GVHD can occur in seemingly immunocompetent patients if the donor has a homozygous HLA haplotype for which the recipient is heterozygous (random donor and recipient partial HLA matching has been estimated to be possible in as many as 1 in 7174 in the United States vs. 1 in 874 in Japan), if the product is received from a relative, or if the recipient’s degree of immunocompromise was not known or properly identified before transfusion;

• 2.

  TA-GVHD is almost universally fatal;

• 3.

  The adverse effects of irradiation on the blood product and its constituents are minimal; and

• 4.

  The cost of irradiating products is modest.

Universal irradiation is practiced in some institutions within and outside the United States (e.g., Japan, where the risk of inadvertent, nonrelative partial matching of HLA haplotypes has been estimated as 1:874).