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#33
MEASURING T CELL IMMUNE FUNCTION IN RENAL RECIPIENTS VIA ATP SYNTHESIS AS AN INDICATOR OF ACTIVATION.
Angela D. Burnette, B.S. , Karen Mohler B.S.,MT and Nancy L. Reinsmoen, Ph.D. . Durham NC, Duke University Medical Center, 27710, Pathology .

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Throughout clinical transplantation immune parameters have been sought to predict long-term graft outcome. To better understand immune cell functions a whole blood assay was developed to measure increases in iATP synthesis by CD4+ T cells in response to stimulation with PHA (ImmuKnow™, Cylex Inc.®) which yields a rapid assessment of the early events in T cell activation without the requirement of long-term culture. We adapted this assay to testing previously frozen peripheral blood lymphocytes (PBLs). Our goal was to measure the iATP levels (ng/ml) generated subsequent to PHA stimulation of PBLs from kidney (KD) recips procured at various times pre-(pretx) and posttransplant(posttx) to determine if these levels correlated with clinical events such as acute rejection (AR). Briefly, frozen PBLs were thawed and cultured overnight with PHA. The CD4+ cells were magnetically selected and lysed. The light produced by luciferin and luciferase in the presence of the released ATP was measured in a luminometer and converted to ng/ml. We tested cells obtained pretx and various times posttx from 29 KD recips with or without AR (Table). At >200 ATP ng/ml (HIGH) range 63% (12/19) experienced AR developing from 5 days to 3y2mo posttx. Of those 12, we were able to study 8 recips posttx and 63% (5/8) had values (within ± 2mo AR) higher than their pretx measurement. Only 20% (2/10) developed AR at <200 ATP ng/ml (LOW). The negative predictive value was 80% for predicting those at low risk for AR. These results suggest that measuring the pretx iATP ng/ml for KD recips provides a useful indication of potential AR (>200 ATP ng/ml at increased risk for AR). Monitoring the posttx iATP ng/ml values gives insight to whether the recip is at risk for developing AR.

	No. Pts.	AR	No AR
HIGH	19	12	7
LOW	10	2	8
TOTAL	29	14	15