Massive elevation of procalcitonin plasma levels in the absence of infection in kidney transplant patients treated with pan-T-cell antibodies

Objective: To determine the value of procalcitonin (PCT) monitoring in tran splant patients receiving pan-T-cell antibody therapy. Design: Retrospective clinical study. Setting: A collaborative study between the Institute of Medical Immunology, the Department of Nephrology and Internal Intensive Care, both Charite, Hu mboldt University Berlin, and the Department of Laboratory Medicine, Friedr ichshain Hospital, Berlin, Germany. Patients and interventions: Thirty-one patients were included in the study: 8 kidney transplant patients with acute rejection episodes, 5 receiving OK T3 monoclonal antibody therapy, 3 receiving steroid bolus therapy; 21 patie nts undergoing renal transplantation, 11 receiving ATG perioperatively, 10 without ATG administration; 2 patients undergoing renal transplantation and receiving anti-IL-2R mAb. Measurements and results: Procalcitonin (PCT) and tumor necrosis factor (TN F) alpha plasma levels were measured in infection-free transplant patients treated with the pan-T-cell antibodies ATG or OKT3. We found PCT plasma con centrations up to 600 ng/ml (reference < 0.5 ng/ml), which are comparable t o those seen in severe sepsis. Increases in TNF-<alpha> plasma levels prece ded the rises in PCT After peaking on day 1 of therapy the PCT plasma conce ntrations returned to normal values independently of further antibody admin istration. In contrast, steroid bolus therapy or anti-interleukin 2 recepto r mAb administration did not increase plasma PCT or TNF-alpha levels. Conclusions: PCT monitoring for evaluating infectious complications in kidn ey transplant patients must be very careful during pan-T-cell antibody ther apy.