Assessment of donor T-cell function in cellular blood components by the CD69 induction assay: effects of storage, gamma radiation, and photochemical treatment

BACKGROUND: Functional donor T-lymphocytes in blood components may cause a variety of transfusion complications. A flow cytometric assay based on the measurement of induced CD69 expression may be an alternative to cell prolif eration methods in determining the functional status of these cells in bloo d components. STUDY DESIGN AND METHODS: Seven units of whole blood, RBCs, and platelet co ncentrates (PCs) were stored under blood bank conditions. Half of 3 PCs eac h were gamma-radiated or treated with UVA+psoralen; the other half served a s controls. Samples were analyzed for phorbolester-induced expression of CD 69 as an indicator of cell responsiveness and for exclusion of propidium io dide as a measure of cell membrane integrity and viability. RESULTS: CD69 inducibility and propidium iodide exclusion decreased exponen tially (half-life, 3.3 and 8.1 days, respectively) during cold blood storag e. Irradiation and UVA+psoralen treatment of PCs immediately reduced CD69 i nducibility to 21 percent (controls, 82%; p = 0.004) and 12 percent (contro ls, 95%; p = 0.0008), respectively. The proportion of cells capable of prop idium iodide exclusion was similar in treated samples and controls, but it declined faster in the treated samples during subsequent storage. CONCLUSION: Flow cytometric measurement of CD69 induction can be adapted to provide quantitative assessment of T-cell function in blood components. Re sults obtained by the CD69 assay are in general agreement with those previo usly reported by use of proliferation methods; the assay may be useful for special applications in transfusion medicine.