Transfusion-associated graft-versus-host disease reexamined: potential for improved prevention using a universally applied intervention.

BACKGROUND STUDY DESIGN AND METHODS Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare, often fatal complication of blood transfusion that can occur in immunocompromised or immunocompetent recipients and is the result of viable T cells present in the blood components transfused. We examined the TA-GVHD clinical case literature including numerous original clinical case reports and several comprehensive case series. We also evaluated recent in vitro experimental data on the inhibition of T cell proliferation, comparing the effect of a specific pathogen inactivation (PI) technology to that of the Food and Drug Administration-recommended gamma irradiation dose of 2500 cGy. RESULTS CONCLUSION We identified 12 published TA-GVHD cases with atypical/milder or delayed symptom presentations and/or an atypical clinical course; these included cases attributed to leukoreduced or suboptimally irradiated units. We summarize recent in vitro data using a sensitive limiting dilution assay that establish that, compared to irradiation at the recommended 2500 cGy dose, PI using amotosalen/ultraviolet A, or amustaline/glutathione achieves a greater degree of inhibition of T cell proliferation. We propose that TA-GVHD has a spectrum of disease severity indicating that additional mild cases may still occur but be undiagnosed and/or underreported, opening up the possibility, supported by in vitro experimental data, that irradiation at the currently established dose may not be fully protective. Furthermore, since many US institutions use component irradiation selectively only for immunocompromised patients, immunocompetent recipients are not fully protected. PI technologies appear to be at least equal to, if not better than, gamma irradiation in abrogating the ability of T cells to proliferate, and if applied to all blood components, protection against TA-GVHD would be an additional benefit that would allow for the elimination of component irradiation.