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 transplant 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, Humboldt University Berlin, and the Department of Laboratory Medicine, Friedrichshain Hospital, Berlin, Germany. Patients and interventions: Thirty-one patients were included in the study: 8 kidney transplant patients with acute rejection episodes, 5 receiving OKT3 monoclonal antibody therapy, 3 receiving steroid bolus therapy; 21 patients 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 (TNF) α plasma levels were measured in infection-free transplant patients treated with the pan-T-cell antibodies ATG or OKT3. We found PCT plasma concentrations up to 600 ng/ml (reference <0.5 ng/ml), which are comparable to those seen in severe sepsis. Increases in TNF-α plasma levels preceded the rises in PCT. After peaking on day 1 of therapy the PCT plasma concentrations returned to normal values independently of further antibody administration. In contrast, steroid bolus therapy or anti-interleukin 2 receptor mAb administration did not increase plasma PCT or TNF-α levels. Conclusions: PCT monitoring for evaluating infectious complications in kidney transplant patients must be very careful during pan-T-cell antibody therapy.