Universal or selective irradiation: a comparison of approaches

Area of Science:

• Transfusion Medicine
• Immunology
• Hematology

Background:

• Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare but often fatal complication of blood transfusions.
• Proposed mechanisms include one-way HLA matching and recipient immunosuppression, with ongoing debate about their relative importance.

Purpose of the Study:

• To clarify the independent roles of one-way HLA matching and immunosuppression in the pathogenesis of TA-GVHD.
• To inform strategies for TA-GVHD prevention based on regional differences in HLA homogeneity and TA-GVHD incidence.

Main Methods:

• Review of existing literature and clinical observations regarding TA-GVHD occurrence in different geographical regions.
• Analysis of the impact of universal leukoreduction and component irradiation on TA-GVHD rates.

Main Results:

• TA-GVHD has occurred in immunocompetent patients, primarily driven by the one-way HLA match mechanism, irrespective of immunosuppression.
• Countries with high HLA homogeneity, like Japan, have successfully reduced TA-GVHD with universal irradiation.
• Universal leukoreduction decreased TA-GVHD, but cases persist, particularly in immunocompetent individuals.

Conclusions:

• One-way HLA matching is a ubiquitous and independent mechanism for TA-GVHD, capable of occurring in any transfusion setting.
• Area-specific prevention strategies should consider local TA-GVHD frequency and irradiation drawbacks.
• Universal irradiation of cellular components may be necessary for complete TA-GVHD eradication due to its high fatality.