Effects of hypoxic storage on the efficacy of gamma irradiation in abrogating lymphocyte proliferation and on the quality of gamma‐irradiated red blood cells in additive solution 3

Gamma irradiation of blood products is used to prevent transfusion-associated graft-versus-host disease by inhibiting the proliferation of lymphocytes that are implicated in the disease. Gamma irradiation also damages the red blood cells (RBCs). It is unknown whether hypoxia reduces the efficacy of gamma irradiation in inhibiting lymphocyte proliferation (LP). The objectives of the study were to investigate the effects of hypoxia on gamma irradiation-induced inhibition of LP and on the in vitro properties of RBCs.Forty-four units (300-340 ml each) of less than 8-h-old ABO-matched leukocyte reduced red cell concentrates (LR-RCC) in additive solution 3 were pooled in pairs. Peripheral blood mononuclear cells were isolated from non-leukocyte reduced RCCs and added back to the pool at a final concentration of 2 × 105 /ml. The pool was divided equally into a conventional storage bag A and a hypoxic processing and storage bag B. The units were gamma-irradiated at 25Gy on day 7 for the LP experiment and on either day 7 or 14 for the RBC quality experiments. LP was measured using a limiting dilution assay, and several in vitro metrics of RBCs were measured.Gamma irradiation inhibited T-lymphocyte proliferation by 4.7 × 104 -fold reduction in both hypoxic and conventional storage. The in vitro metrics of RBC quality were better preserved in hypoxic storage.T lymphocytes present in hypoxic RBC are equally susceptible to gamma irradiation as conventional storage. Hypoxic storage also reduces the deleterious effects of gamma irradiation on RBCs.