An International Consensus List of Potentially Clinically Significant Drug-Drug Interactions in Older People.

OBJECTIVES: We aimed to establish an explicit list of potentially clinically significant drug-drug interactions (DDIs) in people aged ≥65 years. DESIGN: A preliminary list of potentially clinically significant DDIs was compiled, based on 154 DDIs identified from literature review. Subsequently, a 2-round online Delphi survey was undertaken with a multidisciplinary expert panel. A consensus meeting and a final round were conducted to validate the final DDI list and the scope of information provided. SETTING AND PARTICIPANTS: Twenty nine experts, including geriatricians and clinical pharmacists from 8 European countries. MEASURES: For each DDI, in the first 2 rounds, experts were asked to score the severity of potential harm on a 5-point Likert-type scale. DDIs were directly included on the final list if the median score was 4 (major) or 5 (catastrophic). DDIs with a median score of 3 (moderate) were discussed at a consensus meeting and included if ≥75% of participants voted for inclusion in the final round. RESULTS: Consensus was achieved on 66 potentially clinically significant DDIs (28 had a median score of 4/5 and 48 of 3 in the Delphi survey). Most concerned cardiovascular, antithrombotic, and central nervous system drugs. The final list includes information on the mechanism of interaction, harm, and management. Treatment modification is recommended for three-quarters of DDIs. CONCLUSION AND IMPLICATIONS: We validated a list of potentially clinically significant DDIs in older people, which can be used in clinical practice and education to support identification and management of DDIs or to assess prevalence in epidemiologic and intervention studies.

A major secretory defect of tumour-infiltrating T lymphocytes due to galectin impairing LFA-1-mediated synapse completion.

Surface galectin has been shown to contribute to dysfunctions of human tumour-infiltrating lymphocytes (TILs). We show here that galectin-covered CD8 TILs produce normal amounts of intracellular cytokines, but fail to secrete them because of defective actin rearrangements at the synapse. The non-secreting TILs also display reduced adhesion to their targets, together with defective LFA-1 recruitment and activation at the synapse. These defects are relieved by releasing surface galectin. As mild LFA-1 blockade on normal blood T cells emulate the defects of galectin-covered TILs, we conclude that galectin prevents the formation of a functional secretory synapse by preventing optimal LFA-1 triggering. Our results highlight a major secretory defect of TILs that is not revealed by widely used intracellular cytokine immunomonitoring assays. They also provide additional insights into the T-cell response, by showing that different thresholds of LFA-1 triggering are required to promote the intracellular production of cytokines and their secretion.

A biased competition theory of cytotoxic T lymphocyte interaction with tumor nodules.

The dynamics of the interaction between Cytotoxic T Lymphocytes (CTL) and tumor cells has been addressed in depth, in particular using numerical simulations. However, stochastic mathematical models that take into account the competitive interaction between CTL and tumors undergoing immunoediting, a process of tumor cell escape from immunesurveillance, are presently missing. Here, we introduce a stochastic dynamical particle interaction model based on experimentally measured parameters that allows to describe CTL function during immunoediting. The model describes the competitive interaction between CTL and melanoma cell nodules and allows temporal and two-dimensional spatial progression. The model is designed to provide probabilistic estimates of tumor eradication through numerical simulations in which tunable parameters influencing CTL efficacy against a tumor nodule undergoing immunoediting are tested. Our model shows that the rate of CTL/tumor nodule productive collisions during the initial time of interaction determines the success of CTL in tumor eradication. It allows efficient cytotoxic function before the tumor cells acquire a substantial resistance to CTL attack, due to mutations stochastically occurring during cell division. Interestingly, a bias in CTL motility inducing a progressive attraction towards a few scout CTL, which have detected the nodule enhances early productive collisions and tumor eradication. Taken together, our results are compatible with a biased competition theory of CTL function in which CTL efficacy against a tumor nodule undergoing immunoediting is strongly dependent on guidance of CTL trajectories by scout siblings. They highlight unprecedented aspects of immune cell behavior that might inspire new CTL-based therapeutic strategies against tumors.

Activation of the ancestral polarity regulator protein kinase C zeta at the immunological synapse drives polarization of Th cell secretory machinery toward APCs.

A key feature in T lymphocyte biology is that Th cells rapidly polarize their secretory machinery toward cognate APCs. The molecular mechanisms of these dynamic Th cell responses and their impact on APC biology remain to be elucidated. In this study, we demonstrate that protein kinase Czeta (PKCzeta) is rapidly activated at the immunological synapse (IS) in human Th cells interacting with cognate dendritic cells (DCs) and that a functional PKCzeta is required for the polarization of Th cell secretory machinery toward DCs. We also show that PKCzeta-dependent Th cell polarization allows dedicated delivery of IFN-gamma and CD40L at the IS and is required for the activation of cognate DCs to IL-12 production. PKCzeta synaptic activation is a low-threshold phenomenon and, in Th cells interacting with multiple DCs, selectively occurs at the IS formed with the DCs offering the strongest stimulus leading to dedicated Th cell polarization. Our results identify the PKCzeta signaling pathway as a key component of the Th cell polarization machinery and provide a molecular basis for T cell-dedicated activation of cognate DCs.