1Lobna A. Abou-Shamaa, 1Zakia A. Abdel Rahman, 2Eglal A. El-Sherbini, 3Mokhtara N. Saudi, 3Iman M. El-Banna
lImmunology, 2Microbiology Departments, 3Blood Bank, Medical Research Institute, University of Alexandria, Egypt
Allogeneic blood transfusion is the most common allotransplantation procedure performed without previous HLA-typing. The presence of viable donor antigen presenting cells (APCs) capable of presenting costimulatory signals appears to be essential for alloimmunization. We evaluated the effect of refrigerated blood storage on the degree of apoptosis in 25 blood donor's seronegative for HIV, HCV and HBV. The degree of apoptosis was assessed using photometric sandwich-enzyme immunoassay for qualitative and quantitative determination of cytoplasmic histone associated DNA. During refrigerated storage, lymphomononuclear cells in donor blood progressively undergo apoptosis starting from the first day and reaching a maximum increase at 8 days for both lymphocytes and monocytes. The % change of apoptosis was 104.7 ± 13.5 and 166 ± 25.4 at 8 days and 95.9 ± 26.1 and 41.1 ± 14.8 at 15 days, respectively). It is suggested that, whereas transfusions of fresh blood may lead to alloimmunization, the functional impairment and death of donor's APCs (monocytes) during storage eliminates their ability to stimulate cytotoxic immune response. In addition, loss of function and death of donor T cells during storage preclude the possibility for development of post-transfusion graft versus host disease. So, apoptosis of contaminating leukocytes and duration of cold blood storage should be considered in transfusion medicine.