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Aims: Knowledge about adverse drug events caused by drug-drug interactions (DDI-ADEs) is limited. We aimed to provide detailed insights about DDI-ADEs related to three frequent, high-risk potential DDIs (pDDIs) in the critical care setting: pDDIs with international normalized ratio increase (INR + ) potential, pDDIs with acute kidney injury (AKI) potential, and pDDIs with QTc prolongation potential., Methods: We extracted routinely collected retrospective data from electronic health records of intensive care units (ICUs) patients (≥18 years), admitted to ten hospitals in the Netherlands between January 2010 and September 2019. We used computerized triggers (e-triggers) to preselect patients with potential DDI-ADEs. Between September 2020 and October 2021, clinical experts conducted a retrospective manual patient chart review on a subset of preselected patients, and assessed causality, severity, preventability, and contribution to ICU length of stay of DDI-ADEs using internationally prevailing standards., Results: In total 85 422 patients with ≥1 pDDI were included. Of these patients, 32 820 (38.4%) have been exposed to one of the three pDDIs. In the exposed group, 1141 (3.5%) patients were preselected using e-triggers. Of 237 patients (21%) assessed, 155 (65.4%) experienced an actual DDI-ADE; 52.9% had severity level of serious or higher, 75.5% were preventable, and 19.3% contributed to a longer ICU length of stay. The positive predictive value was the highest for DDI-INR + e-trigger (0.76), followed by DDI-AKI e-trigger (0.57)., Conclusion: The highly preventable nature and severity of DDI-ADEs, calls for action to optimize ICU patient safety. Use of e-triggers proved to be a promising preselection strategy., (© 2023 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Autoreactive CD8(+) T cells recognizing autoantigens expressed by pancreatic islets lead to the destruction of insulin-producing beta cells in type 1 diabetes (T1D), but these T cells also occur in healthy subjects. We tested the hypothesis that uncontrolled expansion of diabetogenic T cells in patients occurs, resulting from failure to activate apoptosis. We compared function, transcriptome and epigenetic regulation thereof in relation with fate upon repeated exposure to islet-autoantigen of islet autoreactive T cells from healthy and type 1 diabetic donors with identical islet epitope specificity and HLA-A2 restriction. Patient's T cells proliferated exponentially, whereas those of non-diabetic origin succumbed to cell death. Transcriptome analysis revealed reduced expression of TRAIL, TRAIL-R2, FAS and FASLG (members of the extrinsic apoptosis pathway) in patient-derived compared with healthy donor-derived T cells. This was mirrored by increased expression of microRNAs predicted to regulate these particular genes, namely miR-98, miR-23b and miR-590-5p. Gene-specific targeting by these microRNAs was confirmed using dual-luciferase reporter assays. Finally, transfection of these microRNAs into primary T cells reduced FAS and TRAIL mRNA underscoring their functional relevance. We propose that repression of pro-apoptotic pathways by microRNAs contributes to unrestricted expansion of diabetogenic cytotoxic T cells, implicating microRNA-mediated gene silencing in islet autoimmunity in T1D.

Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) is a protein receptor that downregulates the immune system. CTLA4 gene variants associate with various autoimmune diseases, including type 1 diabetes. Fine mapping of the genetic risk has shown that the genomic region near CTLA4 marked by the single-nucleotide polymorphism (SNP) CT60A/G (rs3087243) acts as a susceptibility factor. Yet, the functional basis for the increased susceptibility conferred by rs3087243 remains unclear. We demonstrate that the length of the dinucleotide (AT)n repeat within the CTLA4 3' untranslated region (3'UTR) strongly associates with the risk of SNP CT60A/G (P<6.5 × 10(-72)). Genomic (AT)n repeat length inversely correlated with CTLA4 messenger RNA (mRNA) and protein levels in islet autoreactive T-cell lines. Transfer of a long (AT)n element into T cells lead to a reduction of mRNA compared to a short (AT)n element. Thus, this study provides evidence for a role of the CTLA4 3'UTR (AT)n repeat in the increased genetic risk for islet autoimmunity associated with the CTLA4 locus.

Aims/hypothesis: Thymic expression of self-antigens during T-lymphocyte development is believed to be crucial for preventing autoimmunity. It has been suggested that G6PC2, the gene encoding islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), is differentially spliced between pancreatic beta cells and the thymus. This may contribute to incomplete elimination of IGRP-specific T lymphocytes in the thymus, predisposing individuals to type 1 diabetes. We tested whether specific splice variation in islets vs thymus correlates with loss of tolerance to IGRP in type 1 diabetes., Methods: Expression of G6PC2 splice variants was compared among thymus, purified medullary thymic epithelial cells and pancreatic islets by RT-PCR. Differential immunogenicity of IGRP splice variants was tested in patients and healthy individuals for autoantibodies and specific cytotoxic T lymphocytes using radiobinding assays and HLA class I multimers, respectively., Results: Previously reported G6PC2 splice variants, including full-length G6PC2, were confirmed, albeit that they occurred in both pancreas and thymus, rather than islets alone. Yet, their expression levels were profoundly greater in islets than in thymus. Moreover, three novel G6PC2 variants were discovered that occur in islets only, leading to protein truncations, frame shifts and neo-sequences prone to immunogenicity. However, autoantibodies to novel or known IGRP splice variants did not differ between patients and healthy individuals, and similar frequencies of IGRP-specific cytotoxic T lymphocytes could be detected in both patients with type 1 diabetes and healthy individuals., Conclusions/interpretation: We propose that post-transcriptional variation of tissue-specific self-proteins may affect negative thymic selection, although this need not necessarily lead to disease.

The genetic variation causal for predisposition to type 1 diabetes (T1D) remains unidentified for the majority of known T1D risk loci. MicroRNAs function as post-transcriptional gene regulators by targeting microRNA-binding sites in the 3' untranslated regions (UTR) of mRNA. Genetic variation within the 3'-UTR of T1D-associated genes may contribute to T1D development by altering microRNA-mediated gene regulation. In silico analysis of variable sites predicted altered microRNA binding in established T1D loci. Functional implications were assessed for variable sites in the 3'-UTR of T1D candidate risk genes CTLA4 and IL10, both involved in immune regulation. We confirmed that in these genes 3'-UTR variation either disrupted or introduced a microRNA-binding site, affecting the repressive capacity of miR-302a* and miR-523, respectively. Our study points to the potential of 3'-UTR variation to affect T1D pathogenesis by altering post-transcriptional gene regulation by microRNAs.

The aims of this study were to assess and compare dose delivery and dose variability of pressurized metered dose inhalers (pMDI)/spacers in wheezy infants in daily life and to investigate factors influencing aerosol delivery. In an open randomized crossover study in 25 wheezy infants aged 5-26 months, a metal spacer (Nebuchamber), a detergent coated (DC) and a non-detergent coated (nonDC) plastic spacer (Babyhaler) were tested at home for 7 days each. Budesonide (200 microg b.i.d) was administered via a Nebuchamber or fluticasone (125 microg b.i.d) via a Babyhaler. Aerosol was trapped in filters, positioned between the spacer and face mask. Cooperation was scored on diary cards. Electrostatic charge (ESC) of the spacers was measured. Evaluations of the administration technique were made from video recordings. Median (range) dose delivery of the filters expressed as per cent (%) of nominal dose, was 34% (3-59), 23% (1-49), and 41% (12-55) for the Nebuchamber, nonDC-Babyhaler, and DC-Babyhaler respectively. Considerable dose variability was found, median (range) within-subject dose variability, expressed as coefficient of variation, for the Nebuchamber (49% (15-249)) was significantly higher when compared with both nonDC- (36% (12-325)) and DC-Babyhalers (27% (10-122)), for which dose variabilities were similar. Detergent coating was effective to reduce electrostatic charge, and to increase dose delivery, but had no effect on dose variability. Bad cooperation was an important cause for high dose variability for all spacers (r=0.5-0.6, p<0.02). Many mistakes were made during the administration procedure.