When is irradiated blood indicated for transfusion?

When to Give Irradiated Blood Products

Irradiated blood products (minimum 25 Gy gamma irradiation) are required for all patients at risk of transfusion-associated graft-versus-host disease (TA-GVHD), including stem cell transplant recipients, severely immunocompromised patients, and recipients of blood from blood relatives. 1

High-Risk Populations Requiring Irradiated Blood

Stem Cell Transplant Recipients

• All allogeneic hematopoietic stem cell transplant (HSCT) recipients require irradiated blood products from the start of conditioning until at least 6 months post-transplant, with extension if chronic GVHD develops 2
• All autologous HSCT recipients require irradiated blood products from 7 days before stem cell harvest until 3 months post-transplant 2
• Stem cell donors also require irradiated blood products 1

Severe Immunodeficiency States

• Congenital immunodeficiency disorders (e.g., DiGeorge syndrome, severe combined immunodeficiency) 1
• Hodgkin's lymphoma patients due to disease-associated severe immunosuppression 1

Immunosuppressive Drug Therapy

• Purine nucleoside analog therapy including fludarabine, clofarabine, and bendamustine 1
• Antithymocyte globulin (ATG) therapy 1
• Alemtuzumab (anti-CD52) therapy 1

Blood from Relatives

• All transfusions from first- or second-degree blood relatives require irradiation, regardless of recipient immune status, due to increased risk of HLA homozygosity 1, 3
• Patients receiving HLA-matched platelets from partially matched family members 1, 3

Fetal and Neonatal Populations

• Intrauterine transfusions 3
• Premature infants 3

Blood Components Requiring Irradiation

Only cellular blood components need irradiation: 1, 3

• Red blood cells (packed RBCs and whole blood)
• Platelets
• Granulocytes

Plasma products (FFP, cryoprecipitate) do NOT require irradiation as they contain no viable lymphocytes 3

Technical Specifications

• Minimum irradiation dose: 25 Gy (2500 cGy) is required to completely inactivate T lymphocytes 1, 2, 3
• Irradiation should be performed as close to transfusion time as possible 4
• Leukoreduction alone is insufficient to prevent TA-GVHD and does not replace the need for irradiation 1, 2

Populations NOT Requiring Routine Irradiation

Routine irradiation is NOT recommended for: 1

• Patients with acute leukemia receiving standard chemotherapy (not purine analogs)
• Patients with AIDS
• Patients with solid tumors (unless receiving highly immunosuppressive therapy)

Critical Pitfalls to Avoid

• Do not assume leukoreduction prevents TA-GVHD – it does not, and irradiation is still required 1, 2
• Communicate proactively with your blood bank about patients requiring irradiated products, as approximately 30% of centers fail to irradiate for consensus indications 1, 2
• Plan ahead for smaller centers that lack irradiators and must send products to regional centers, causing potential delays 1, 2
• Do not discontinue irradiated products prematurely after transplantation – follow the specified time frames (6+ months for allogeneic, 3 months for autologous) 2
• Remember that TA-GVHD is almost universally fatal (mortality >90%), making prevention through irradiation essential 3, 5, 6

Clinical Recognition of TA-GVHD

If irradiation is inadvertently omitted, watch for symptoms 8-10 days post-transfusion: 3, 6

• Fever and maculopapular skin rash with desquamation
• Severe diarrhea and hepatitis (elevated liver enzymes)
• Pancytopenia due to bone marrow aplasia
• These symptoms may be difficult to distinguish from conditioning-related toxicity or transplant-related GVHD 2