Learned immunosuppressive placebo responses in renal transplant patients.

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 (ƞp2 = 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.

Repeated Systemic Treatment with Rapamycin Affects Behavior and Amygdala Protein Expression in Rats.

Background: Clinical data indicate that therapy with small-molecule immunosuppressive drugs is frequently accompanied by an incidence rate of neuropsychiatric symptoms. In the current approach, we investigated in rats whether repeated administration of rapamycin, reflecting clinical conditions of patients undergoing therapy with this mammalian target of rapamycin inhibitor, precipitates changes in neurobehavioral functioning. Methods: Male adult Dark Agouti rats were daily treated with i.p. injections of rapamycin (1, 3 mg/kg) or vehicle for 8 days. On days 6 and 7, respectively, behavioral performance in the Elevated Plus-Maze and the Open-Field Test was evaluated. One day later, amygdala tissue and blood samples were taken to analyze protein expression ex vivo. Results: The results show that animals treated with rapamycin displayed alterations in Elevated Plus-Maze performance with more pronounced effects in the higher dose group. Besides, an increase in glucocorticoid receptor density in the amygdala was seen in both treatment groups even though p-p70 ribosomal S6 kinase alpha, a marker for mammalian target of rapamycin functioning, was not affected. Protein level of the neuronal activity marker c-Fos was again only elevated in the higher dose group. Importantly, effects occurred in the absence of acute peripheral neuroendocrine changes. Conclusions: Our findings indicate that anxiety-related behavior following rapamycin treatment was not directly attributed to mTOR-dependent mechanisms or stress but rather due to hyperexcitability of the amygdala together with glucocorticoid receptor-regulated mechanism(s) in this brain region. Together, the present results support the contention that subchronic treatment with rapamycin may induce neurobehavioral alterations in healthy, naive subjects. We here provide novel insights in central effects of systemic rapamycin in otherwise healthy subjects but also raise the question whether therapy with this drug may have detrimental effects on patients' neuropsychological functioning during immune therapy.

Granzyme B producing B-cells in renal transplant patients.

OBJECTIVES: A separate subset of Granzyme B (GrB) producing B-cells regulating T-cell mediated immunity has been identified. In the present study, we investigated the role of GrB+ B-cells in renal transplant patients (RTX). METHODS: 12 healthy controls (HC) and 26 RTX patients were enrolled. In addition, 19 healthy volunteers treated with cyclosporine A (CsA) were enrolled. GrB+ B-cells were determined via flow cytometry. RESULTS: RTX Patients showed a diminished fraction of GrB+ B-cells as compared to HC. CsA treatment of healthy volunteers had no impact on the development of GrB+ B-cells. RTX patients with a history of allograft rejection showed an increased frequency of GrB+ B-cells. RTX patients with at least one episode of CMV viremia tended to have lower GrB+ B-cells as compared to patients without viremic episodes. CONCLUSION: We demonstrate that treatment with CsA does not impair the development of GrB+ B-cells. GrB+ B-cells may have a dual role in renal transplantation as regulatory cells to maintain allospecific tolerance and as effector cells enhancing viral control.

Applications and limitations of behaviorally conditioned immunopharmacological responses.

The importance of placebo responses for the treatment of various medical conditions has increasingly been recognized, whereas knowledge and systematic application in clinical settings are still sparse. One possible application for placebo responses in pharmacotherapy is given by learning paradigms, such as behaviorally conditioned immunosuppression, aiming at drug dose reduction while maintaining therapeutic efficacy of drug treatment. In an established learning paradigm of conditioned taste aversion/avoidance (CTA) in both, rats and humans, respectively, a novel-tasting drinking solution (conditioned stimulus, CS) is paired with an injection of the immunosuppressive drug cyclosporine A (CsA) as unconditioned stimulus (US). The conditioned response, evoked by re-presenting the CS alone at a later time, is reflected by avoidance behavior of consuming the solution (conditioned taste aversion; CTA) and a diminished interleukin (IL)-2 and interferon (IFN)-γ cytokine production as well as mRNA expression of rat splenic T cells or human peripheral T lymphocytes, closely mimicking the immunosuppressive effects of CsA. However, due to unreinforced CS-re-exposure conditioned responses progressively decreases over time (extinction), reflecting a considerable challenge for potential clinical applications of this learned immunosuppression. The present article discusses and critically reviews actual approaches, applications but also limitations of learning paradigms in immune pharmacotherapy.

Acute administration of cyclosporine A does not impair attention or memory performance in healthy men.

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.

Acute Versus Chronic Administration of Calcineurin-Inhibitors Differentially Affect T-Cell Function.

BACKGROUND: Calcineurin-inhibitors (CNI) are used in renal transplant patients (RTX) to prevent rejection. CNI mainly suppress T-cell mediated immunity but very little is known about the impact of long-term treatment with CNI on T-cell function. OBJECTIVE: We investigated the immunological effects of long-term CNI intake in RTX patients in comparison to short-term CNI administration in healthy controls (HC). METHODS: Blood was drawn from 30 RTX patients with long-term CNI treatment. In addition, blood was sampled from HC with short-term CNI treatment (four dosages) before the first and 2 hours after the last CsA intake. T-cells were analyzed for cytokine production, proliferation, and CD25 expression. RESULTS: Short-term CNI reduced T-cell derived IL-2 and IFNγ as well as T-cell proliferation in HC. IFNγ was not suppressed in patients with long-term CNI treatment. IL-2 production, CD25 expression, and T-cell proliferation were enhanced in long-term CNI patients. CONCLUSION: Suppression of IFNγ/IL-2 and T-cell proliferation is weaker during long-term CNI treatment in patients compared to short-term treatment in healthy subjects. Enhanced CD25 expression may lower the threshold for T-cell activation during long-term CNI treatment.

Are Adverse Events Induced by the Acute Administration of Calcineurin Inhibitor Cyclosporine A Behaviorally Conditioned in Healthy Male Volunteers?

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.