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Purpose: The learned immunosuppressive placebo response has been demonstrated in experimental animals, healthy humans, and patients, and is suggested as a therapy for improving immunopharmacologic treatment. It remains unclear, however, whether potential adverse events induced by the drug are also behaviorally conditioned. Employing an established taste-immune learning paradigm in healthy humans using the calcineurin inhibitor and immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus, we investigated whether and to what extent perceived adverse events induced by acute CsA administration are behaviorally conditioned., Methods: A total of 68 healthy male subjects were exposed to the established taste-immune learning paradigm, receiving either placebo or CsA (10 mg/kg) as an unconditioned stimulus, and a novel-tasting drink as a conditioned stimulus., Findings: Subjects repeatedly receiving CsA during acquisition reported significantly more adverse events than did placebo-receiving subjects. However, during reexposure to the conditioned stimulus, the reported adverse events did not differ from those in the placebo control condition., Implications: These data indicate that acute adverse events are not behaviorally conditioned during the learned immunosuppressive response. Our results further strengthen the great potential clinical relevance of employing the learned immunosuppressive placebo response as a therapy to support immunopharmacologic regimens, ultimately aiming to reduce the medical dosages required, thereby minimizing adverse drug events while maximizing the therapeutic benefit in patients. German Clinical Trial Register (www.drks.de) identifier: DRKS00007693., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Patients after organ transplantation or with chronic, inflammatory autoimmune diseases require lifelong treatment with immunosuppressive drugs, which have toxic adverse effects. Recent insight into the neurobiology of placebo responses shows that associative conditioning procedures can be employed as placebo-induced dose reduction strategies in an immunopharmacological regimen. However, it is unclear whether learned immune responses can be produced in patient populations already receiving an immunosuppressive regimen. Thus, 30 renal transplant patients underwent a taste-immune conditioning paradigm, in which immunosuppressive drugs (unconditioned stimulus) were paired with a gustatory stimulus [conditioned stimulus (CS)] during the learning phase. During evocation phase, after patients were reexposed to the CS, T cell proliferative capacity was significantly reduced in comparison with the baseline kinetics of T cell functions under routine drug intake (ƞ p 2 = 0.34). These data demonstrate, proof-of-concept, that learned immunosuppressive placebo responses can be used as a supportive, placebo-based, dose-reduction strategy to improve treatment efficacy in an ongoing immunopharmacological regimen., Competing Interests: The authors declare no conflict of interest., (Copyright © 2018 the Author(s). Published by PNAS.)

There is clinical and experimental evidence that treatment with immunosuppressive and antiproliferative drugs such as the calcineurin inhibitor cyclosporine A (CsA) is associated with mental health problems and neuropsychological disturbances in patients. However, it remains unclear whether and to what extent cognitive functions such as memory and attention processes are affected by the pharmacological treatment. This is partly because of the fact that it is difficult to refer the observed neuropsychological disturbances in patients to the drug itself, to drug-induced immune suppression, or to interaction with other medication or comorbidities. Thus, in a double-blind study with healthy male participants (n=30), we investigated whether short-term intake of therapeutic doses of CsA (4×2.5 mg/kg) affects attention, working memory performance, and anxiety levels, measured with the Tests of Attentional Performance and the State-Trait Anxiety Inventory. The data indicate that short-term CsA-administration and subsequent suppression in interleukin-2 production are accompanied neither by a decrease in attention or memory performance nor by increased anxiety levels in healthy male volunteers, suggesting that the short-term intake of CsA does not impair cognitive functioning. Further studies in healthy humans are needed to determine neurocognitive functions and mood states after short-term or subchronic treatment with different immunosuppressive and antiproliferative drugs.