Effect of Gamma Ray on Number of T-cells In Blood Bags

Introduction: Transfusion associated graft versus host disease is a serious complication of blood transfusion. The main effector cells which are responsible for this reaction are T-lymphocytes. To prevent this complication,the standard method is irradiation of blood bags using gamma ray. Materials and methods:fifty blood bags were collected from donors. Hemoglobin concentration, total lymphocyte count, T-cell% and T-cell counts were measured for each blood unit before and after exposure to 25 Gray dose of gamma ray. Results:there was a statistically significant reduction in means of total lymphocyte count, T-cell% and T-cell count (4.267*109/l ±1.438 vs 1.800*109/l ±0.775, 57.467%±10.501 vs 44.533% ±9.265,2.482*109/l±1.081 vs 0.865*109/l ±0.383) respectively. On the other hand, mean hemoglobin concentration was reduced from14.9±1.6 g/dl to11.2±1.2 g/dl. Conclusion: 1. There was a significant reduction in means of total lymphocyte count, T-Cell% and T-cell numbers after exposure of blood bags to 25 Gy gamma ray. 2. Hb concentration was mildly reduced during irradiation. 3. The reduction in T-cell numbers outweighs the reduction in Hb concentration if TA-GvHD is to be prevented.