Muscle Toxicity of Drugs: When Drugs Turn Physiology into Pathophysiology.

Drugs are prescribed to manage or prevent symptoms and diseases, but may sometimes cause unexpected toxicity to muscles. The symptomatology and clinical manifestations of the myotoxic reaction can vary significantly between drugs and between patients on the same drug. This poses a challenge on how to recognize and prevent the occurrence of drug-induced muscle toxicity. The key to appropriate management of myotoxicity is prompt recognition that symptoms of patients may be drug related and to be aware that inter-individual differences in susceptibility to drug-induced toxicity exist. The most prevalent and well-documented drug class with unintended myotoxicity are the statins, but even today new classes of drugs with unintended myotoxicity are being discovered. This review will start off by explaining the principles of drug-induced myotoxicity and the different terminologies used to distinguish between grades of toxicity. The main part of the review will focus on the most important pathogenic mechanisms by which drugs can cause muscle toxicity, which will be exemplified by drugs with high risk of muscle toxicity. This will be done by providing information on key clinical and laboratory aspects, muscle electromyography patterns and biopsy results, and pathological mechanism and management for a specific drug from each pathogenic classification. In addition, rather new classes of drugs with unintended myotoxicity will be highlighted. Furthermore, we will explain why it is so difficult to diagnose drug-induced myotoxicity, and which tests can be used as a diagnostic aid. Lastly, a brief description will be given of how to manage and treat drug-induced myotoxicity.

The Hypoxia Response Pathway: A Potential Intervention Target in Parkinson's Disease?

Parkinson's disease (PD) is a progressive neurodegenerative disorder for which only symptomatic treatments are available. Both preclinical and clinical studies suggest that moderate hypoxia induces evolutionarily conserved adaptive mechanisms that enhance neuronal viability and survival. Therefore, targeting the hypoxia response pathway might provide neuroprotection by ameliorating the deleterious effects of mitochondrial dysfunction and oxidative stress, which underlie neurodegeneration in PD. Here, we review experimental studies regarding the link between PD pathophysiology and neurophysiological adaptations to hypoxia. We highlight the mechanistic differences between the rescuing effects of chronic hypoxia in neurodegeneration and short-term moderate hypoxia to improve neuronal resilience, termed "hypoxic conditioning". Moreover, we interpret these preclinical observations regarding the pharmacological targeting of the hypoxia response pathway. Finally, we discuss controversies with respect to the differential effects of hypoxia response pathway activation across the PD spectrum, as well as intervention dosing in hypoxic conditioning and potential harmful effects of such interventions. We recommend that initial clinical studies in PD should focus on the safety, physiological responses, and mechanisms of hypoxic conditioning, as well as on repurposing of existing pharmacological compounds. © 2023 International Parkinson and Movement Disorder Society.

Screening and prevalence of cardiac abnormalities on electro- and echocardiography in a large cohort of patients with mitochondrial disease.

BACKGROUND: In patients with primary mitochondrial disease (MD), screening with electrocardiogram (ECG) and transthoracic echocardiography (TTE) is warranted according to current guidelines as structural cardiac abnormalities are frequent. This study aims to evaluate the cardiac phenotype of a large Dutch cohort of patients with MD and investigates whether ECG alone is sufficient for predicting structural cardiac abnormalities on TTE. METHODS: In this retrospective cohort study, genetically confirmed MD patients >18 years old with an available ECG and TTE were included. Newcastle Mitochondrial Disease Scale for Adults (NMDAS) scores were assessed. ECG's were evaluated for rhythm and conduction disorders, voltage criteria for left ventricular hypertrophy (LVH) and repolarization disorders. Echocardiographic evaluation included left and right ventricular volumes and function, and presence of LVH or concentric remodeling. RESULTS: In total, 200 MD patients were included with a median age of 45 years (IQR; 37-57) of whom 36% were male. Of all MD patients, 35% had abnormalities on ECG and 61% on TTE. Most frequent structural cardiac abnormalities on TTE were: global longitudinal strain > - 18% (54%), concentric remodeling (27%) and left ventricular (LV) ejection fraction <52% (14%). Patients with maternally inherited diabetes and deafness (MIDD) and mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) had the highest prevalence of ECG abnormalities (50% and 47%). TTE abnormalities were most prevalent in patients with MIDD (75%), followed by mitochondrial myopathy (MM) (55%), MELAS (47%) and Mitochondrial Epilepsy and Ragged Red Fibers (MERRF) (47%). MD patients with a high disease severity (NMDAS ≥21) had a higher prevalence of ECG abnormalities (44%, p = 0.039) and structural cardiac abnormalities (72%, p = 0.004) compared to patients with a NMDAS score of 11-20 and ≤ 10 (ECG: 34% and 19%; TTE: 63% and 39%). ECG abnormalities had a positive predictive value of 74% and a negative predictive value of 53% for structural cardiac abnormalities on TTE. CONCLUSION: MD patients frequently have cardiac involvement especially patients with MIDD, MELAS or high NMDAS score. ECG as sole screening parameter is insufficient to detect structural cardiac abnormalities.

A role for IL-27p28 as an antagonist of gp130-mediated signaling.

The heterodimeric cytokine interleukin 27 (IL-27) signals through the IL-27Rα subunit of its receptor, combined with gp130, a common receptor chain used by several cytokines, including IL-6. Notably, the IL-27 subunits p28 (IL-27p28) and EBI3 are not always expressed together, which suggests that they may have unique functions. Here we show that IL-27p28, independently of EBI3, antagonized cytokine signaling through gp130 and IL-6-mediated production of IL-17 and IL-10. Similarly, the ability to generate antibody responses was dependent on the activity of gp130-signaling cytokines. Mice transgenic for expression of IL-27p28 showed a substantial defect in the formation of germinal centers and antibody production. Thus, IL-27p28, as a natural antagonist of gp130-mediated signaling, may be useful as a therapeutic for managing inflammation mediated by cytokines that signal through gp130.

Ultrasound and MR muscle imaging in new onset idiopathic inflammatory myopathies at diagnosis and after treatment: a comparative pilot study.

OBJECTIVES: To prospectively compare ultrasound (US) and whole-body MRI for detection of muscle abnormalities compatible with idiopathic inflammatory myopathies (IIM). METHODS: Newly diagnosed IIM patients underwent US (14 muscles) and MRI (36 muscles) at diagnosis and after nine weeks monotherapy with intravenous immunoglobulin. Muscles were compatible with IIM when quantitative US echo-intensity (EI) z scores was ≥1.5, semi-quantitative US Heckmatt score was ≥2, qualitative US was abnormal, or when MRI showed oedema on T2-weighted images. At patient level, findings were classified as abnormal when quantitative US EI z scores was >1.5 (n = 3 muscles), >2.5 (n = 2 muscles) or >3.5 (n = 1 muscle), or if ≥3 muscles showed abnormalities as described above for the other diagnostic methods. RESULTS: At diagnosis, in 18 patients US of 252 muscles revealed abnormalities in 36 muscles (14%) with quantitative, in 153 (61%) with semi-quantitative and in 168 (67%) with qualitative analysis. MRI showed oedema in 476 out of 623 muscles (76%). Five patients (28%) reached abnormal classification with quantitative US, 16 (89%) with semi-quantitative and qualitative US, and all patients (100%) with MRI. Nine-week follow-up of 12 patients showed no change over time with quantitative US or MRI, and a decrease in abnormalities with semi-quantitative US (P <0.01), and qualitative US (P <0.01). CONCLUSION: At diagnosis, MRI was more sensitive than US to detect muscle abnormalities compatible with IIM. Semi-quantitative US and qualitative US detected abnormalities in the majority of the patients while evaluating fewer muscles than MRI and showed change over time after nine weeks of treatment.

Visual versus quantitative analysis of muscle ultrasound in neuromuscular disease.

INTRODUCTION/AIMS: Visual and quantitative muscle ultrasound are both valid diagnostic tools in neuromuscular diseases. To optimize muscle ultrasound evaluation and facilitate its use in neuromuscular disease, we examined the correlation between visual and quantitative muscle ultrasound analysis and their pitfalls. METHODS: Retrospective data from 994 patients with 13,562 muscle ultrasound images were analyzed. Differences in echogenicity z-score distribution per Heckmatt grade and corresponding correlation coefficients were calculated. RESULTS: Overall, there was a correlation of 0.60 between the two scoring systems, with a gradual increase in z-score with increasing Heckmatt grades and vice versa. Patients with a neuromuscular disorder had higher Heckmatt grades (p < 0.001) and z-scores (median z-score = 0.30, p < 0.001) than patients without. The highest Heckmatt grades and z-scores were found in patients with either a dystrophy or inflammatory myopathy (both median Heckmatt grade of 2 and median z score of 0.74 and 1.20, respectively). Discrepant scores were infrequent (<2%), but revealed important pitfalls in both grading systems. DISCUSSION: Visual and quantitative muscle ultrasound are complementary techniques to evaluate neuromuscular disease and have a moderate positive correlation. Importantly, we identified specific pitfalls for visual and quantitative muscle ultrasound and how to overcome them in clinical practice.

Association of diaphragm thickness and echogenicity with age, sex, and body mass index in healthy subjects.

INTRODUCTION/AIMS: Diaphragm ultrasound is increasingly used in the diagnosis of diaphragm dysfunction and to guide respiratory management in patients with neuromuscular disorders and those who are critically ill. However, the association between diaphragm ultrasound variables and demographic factors like age, sex, and body mass index (BMI) are understudied. Such relationships are important for correct interpretation of normative values and comparison with selected patients groups. The aim of this study was to determine the associations between diaphragm ultrasound variables and subject characteristics. METHODS: B-mode ultrasound was used to image the diaphragm at the zone of apposition in 83 healthy subjects. Diaphragm thickness at resting end-expiration (Tend-exp ), diaphragm thickness at maximal end-inspiration (Tmax-insp ), diaphragm thickening ratio (Tmax-insp /Tend-exp ), and diaphragm echogenicity were measured. Multivariate linear regression was used to explore the associations between diaphragm ultrasound variables and subject characteristics. RESULTS: Tend-exp , Tmax-insp , and thickening ratio do not change with age whereas diaphragm echogenicity increases with age. The thickening ratio had a weak negative association with BMI, while Tend-exp was positively associated with BMI. Men had a larger Tend-exp and Tmax-insp than women (Tend-exp 1.6 ± 0.5 and 1.4 ± 0.3 mm; p = .011, Tmax-insp 3.8 ± 1.0 and 3.2 ± 0.9 mm; p = .004), but similar thickening ratios. DISCUSSION: Diaphragm thickness, thickening, and echogenicity measured with ultrasound are associated with factors such as age, BMI, and sex. Therefore, subject characteristics should be considered when interpreting diaphragm ultrasound measurements. In the absence of normative values, matched control groups are a prerequisite for research and in clinical practice.

Intravenous immunoglobulins as first-line treatment in idiopathic inflammatory myopathies: a pilot study.

OBJECTIVES: We explored efficacy and safety of IVIg as first-line treatment in patients with an idiopathic inflammatory myopathy. METHODS: In this investigator-initiated phase 2 open-label study, we included 20 adults with a newly diagnosed, biopsy-proven idiopathic inflammatory myopathy, and a disease duration of less than 9 months. Patients with IBM and prior use of immunosuppressants were excluded. The standard treatment regimen consisted of IVIg (Privigen) monotherapy for 9 weeks: a loading dose (2 g/kg body weight) and two subsequent maintenance doses (1 g/kg body weight) with a 3-week interval. The primary outcome was the number of patients with at least moderate improvement on the 2016 ACR/EULAR Total Improvement Score. Secondary outcomes included time to improvement, the number of patients requiring rescue medication and serious adverse events. RESULTS: We included patients with DM (n = 9), immune-mediated necrotizing myopathy (n = 6), non-specific myositis/overlap myositis (n = 4) and anti-synthetase syndrome (n = 1). One patient was excluded from analyses because of minimal weakness resulting in a ceiling effect. Eight patients (8/19 = 42.0%; Clopper-Pearson 95% CI: 19.6, 64.6) had at least moderate improvement by 9 weeks. Of these, six reached improvement by 3 weeks. Seven patients required rescue medication due to insufficient efficacy and prematurely ended the study. Three serious adverse events occurred, of which one was pulmonary embolism. CONCLUSION: First-line IVIg monotherapy led to at least moderate improvement in nearly half of patients with a fast clinical response in the majority of responders. TRIAL REGISTRATION: Netherlands Trial Register identifier, NTR6160.

Inclusion body myositis in patients with spinocerebellar ataxia types 3 and 6.

OBJECTIVES: To describe the combination of spinocerebellar ataxia (SCA) types 3 and 6 and sporadic inclusion body myositis (IBM). METHODS: A description of five patients with SCA type 3 and 6 who were diagnosed with IBM. We explore possible mechanisms explaining the coexistence of both diseases. RESULTS: The patients with SCA-3 (n=4) and SCA-6 (n=1) developed asymmetric muscle weakness in a pattern suggestive of IBM in the course of their disease. Based on findings of neurological examination and additional investigations (muscle ultrasound, muscle biopsy), the diagnosis of IBM was made in all patients. CONCLUSION: We report on five patients with concomitant SCA and IBM. Our cases may merely illustrate coincidental co-occurrence of IBM and SCA-3/SCA-6. However, the presence of SCA mutations could predispose to the development of IBM in some SCA patients, or, the presence of toxic aggregates and malfunctioning of cellular quality control processes in both diseases could indicate a convergence of disease mechanisms.

Ultrasound can differentiate inclusion body myositis from disease mimics.

INTRODUCTION: The diagnosis of inclusion body myositis (IBM) can be challenging, and its presentation can be confused with other forms of myositis or neuromuscular disorders. In this study we evaluate the ability of quantitative muscle ultrasound to differentiate between IBM and mimicking diseases. METHODS: Patients 50 years of age and older were included from two specialty centers. Muscle echogenicity and muscle thickness of four characteristically involved muscles in IBM were measured and compared with polymyositis (PM)/dermatomyositis (DM), other neuromuscular disorders, and healthy controls. RESULTS: Echogenicity was higher and muscle thickness generally lower in all four muscles in IBM compared with PM/DM and normal controls. When comparing IBM with the comparator groups, the flexor digitorum profundus was the most discriminative muscle. DISCUSSION: Ultrasound appears to be a good test to differentiate established IBM from PM/DM and neuromuscular controls, with value as a diagnostic tool for IBM.

Suppression of autoimmune inflammation of the central nervous system by interleukin 10 secreted by interleukin 27-stimulated T cells.

Excessive inflammation occurs during infection and autoimmunity in mice lacking the alpha-subunit of the interleukin 27 (IL-27) receptor. The molecular mechanisms underlying this increased inflammation are incompletely understood. Here we report that IL-27 upregulated IL-10 in effector T cells that produced interferon-gamma and expressed the transcription factor T-bet but did not express the transcription factor Foxp3. These IFN-gamma+T-bet+Foxp3- cells resembled effector T cells that have been identified as the main source of host-protective IL-10 during inflammation. IL-27-induced production of IL-10 was associated with less secretion of IL-17, and exogenous IL-27 reduced the severity of adoptively transferred experimental autoimmune encephalomyelitis by a mechanism dependent on IL-10. Our data show that IL-27-induced production of IL-10 by effector T cells contributes to the immunomodulatory function of IL-27.

Interleukins 27 and 6 induce STAT3-mediated T cell production of interleukin 10.

Interleukin 10 (IL-10) has a prominent function in regulating the balance between protective and pathological T cell responses. Consistent with that activity, many sources of this cytokine are found in vivo, including from myeloid cells and a variety of T cell subsets. However, although there are many pathways that regulate innate production of IL-10, the factors that govern its synthesis by the adaptive response are poorly understood. Here we report that IL-27 and IL-6 induced T helper type 1 and type 2 cells, as well as T helper cells that produce IL-17, to secrete IL-10. This effect was dependent on the transcription factors STAT1 and STAT3 for IL-27 and on STAT3 for IL-6. Our studies identify a previously unknown pathway that allows the immune system to temper inflammatory responses.

The difficulty of diagnosing NCSE in clinical practice; external validation of the Salzburg criteria.

To improve the diagnostic accuracy of electroencephalography (EEG) criteria for nonconvulsive status epilepticus (NCSE), external validation of the recently proposed Salzburg criteria is paramount. We performed an external, retrospective, diagnostic accuracy study of the Salzburg criteria, using EEG recordings from patients with and without a clinical suspicion of having NCSE. Of the 191 EEG recordings, 12 (12%) was classified as an NCSE according to the reference standard. In the validation cohort, sensitivity was 67% and specificity was 89%. The positive predictive value was 47% and the negative predictive value was 95%. Ten patients in the control group (n = 93) were false positive, resulting in a specificity of 89.2%. The interrater agreement between the reference standards and between the scorers of the Salzburg criteria was moderate; disagreement occurred mainly in patients with an epileptic encephalopathy. The Salzburg criteria showed a lower diagnostic accuracy in our external validation study than in the original design, suggesting that they cannot replace the current practice of careful weighing of both clinical and EEG information on an individual basis.

Autoantibody testing in idiopathic inflammatory myopathies.

The diagnosis and classification of idiopathic inflammatory myopathies are based mainly on clinical and histological features. The discovery of myositis-specific and myositis-associated antibodies has simplified the (sub)classification of inflammatory myopathies. Patients suspected of having an idiopathic inflammatory myopathy should undergo routine antibody testing to gain more insight into distinct phenotypes, comorbidities, treatment response and prognosis. Furthermore, autoantibody testing can help in patients with atypical patterns of weakness or with an unresolved limb-girdle myopathic phenotype, or interstitial lung disease. However, some important technical and methodological issues can hamper the interpretation of antibody testing; for example, some antibodies are not included in the widely available line blots. We aim to provide a practical review of the use of autoantibody testing in idiopathic inflammatory myopathies in clinical practice.

Effect of Mexiletine on Muscle Stiffness in Patients With Nondystrophic Myotonia Evaluated Using Aggregated N-of-1 Trials.

Importance: In rare diseases it is difficult to achieve high-quality evidence of treatment efficacy because of small cohorts and clinical heterogeneity. With emerging treatments for rare diseases, innovative trial designs are needed. Objective: To investigate the effectiveness of mexiletine in nondystrophic myotonia using an aggregated N-of-1 trials design and compare results between this innovative design and a previously conducted RCT. Design, Setting, and Participants: A series of aggregated, double-blind, randomized, placebo-controlled N-of-1-trials, performed in a single academic referral center. Thirty Dutch adult patients with genetically confirmed nondystrophic myotonia (38 patients screened) were enrolled between February 2014 and June 2015. Follow-up was completed in September 2016. Interventions: Mexiletine (600 mg daily) vs placebo during multiple treatment periods of 4 weeks. Main Outcomes and Measures: Reduction in daily-reported muscle stiffness on a scale of 1 to 9, with higher scores indicating more impairment. A Bayesian hierarchical model aggregated individual N-of-1 trial data to determine the posterior probability of reaching a clinically meaningful effect of a greater than 0.75-point difference. Results: Among 30 enrolled patients (mean age, 43.4 [SD, 15.24] years; 22% men; 19 CLCN1 and 11 SCN4A genotype), 27 completed the study and 3 dropped out (1 because of a serious adverse event). In 24 of the 27 completers, a clinically meaningful treatment effect was found. In the Bayesian hierarchical model, mexiletine resulted in a 100% posterior probability of reaching a clinically meaningful reduction in self-reported muscle stiffness for the nondystrophic myotonia group overall and the CLCN1 genotype subgroup and 93% posterior probability for the SCN4A genotype subgroup. In the total nondystrophic myotonia group, the median muscle stiffness score was 6.08 (interquartile range, 4.71-6.80) at baseline and was 2.50 (95% credible interval [CrI], 1.77-3.24) during the mexiletine period and 5.56 (95% CrI, 4.73-6.39) during the placebo period; difference in symptom score reduction, 3.06 (95% CrI, 1.96-4.15; n = 27) favoring mexiletine. The most common adverse event was gastrointestinal discomfort (21 mexiletine [70%], 1 placebo [3%]). One serious adverse event occurred (1 mexiletine [3%]; allergic skin reaction). Using frequentist reanalysis, mexiletine compared with placebo resulted in a mean reduction in daily-reported muscle stiffness of 3.12 (95% CI, 2.46-3.78), consistent with the previous RCT treatment effect of 2.69 (95% CI, 2.12-3.26). Conclusions and Relevance: In a series of N-of-1 trials of mexiletine vs placebo in patients with nondystrophic myotonia, there was a reduction in mean daily-reported muscle stiffness that was consistent with the treatment effect in a previous randomized clinical trial. These findings support the efficacy of mexiletine for treatment of nondystrophic myotonia as well as the feasibility of N-of-1 trials for assessing interventions in some chronic rare diseases. Trial Registration: ClinicalTrials.gov Identifier: NCT02045667.

Timed action of IL-27 protects from immunopathology while preserving defense in influenza.

Infection with influenza virus can result in massive pulmonary infiltration and potentially fatal immunopathology. Understanding the endogenous mechanisms that control immunopathology could provide a key to novel adjunct therapies for this disease. Here we show that the cytokine IL-27 plays a crucial role in protection from exaggerated inflammation during influenza virus infection. Using Il-27ra-/- mice, IL-27 was found to limit immunopathology, neutrophil accumulation, and dampened TH1 or TH17 responses via IL-10-dependent and -independent pathways. Accordingly, the absence of IL-27 signals resulted in a more severe disease course and in diminished survival without impacting viral loads. Consistent with the delayed expression of endogenous Il-27p28 during influenza, systemic treatment with recombinant IL-27 starting at the peak of virus load resulted in a major amelioration of lung pathology, strongly reduced leukocyte infiltration and improved survival without affecting viral clearance. In contrast, early application of IL-27 impaired virus clearance and worsened disease. These findings demonstrate the importance of IL-27 for the physiological control of immunopathology and the potential value of well-timed IL-27 application to treat life-threatening inflammation during lung infection.

IL-27 receptor signalling restricts the formation of pathogenic, terminally differentiated Th1 cells during malaria infection by repressing IL-12 dependent signals.

The IL-27R, WSX-1, is required to limit IFN-γ production by effector CD4⁺ T cells in a number of different inflammatory conditions but the molecular basis of WSX-1-mediated regulation of Th1 responses in vivo during infection has not been investigated in detail. In this study we demonstrate that WSX-1 signalling suppresses the development of pathogenic, terminally differentiated (KLRG-1⁺) Th1 cells during malaria infection and establishes a restrictive threshold to constrain the emergent Th1 response. Importantly, we show that WSX-1 regulates cell-intrinsic responsiveness to IL-12 and IL-2, but the fate of the effector CD4⁺ T cell pool during malaria infection is controlled primarily through IL-12 dependent signals. Finally, we show that WSX-1 regulates Th1 cell terminal differentiation during malaria infection through IL-10 and Foxp3 independent mechanisms; the kinetics and magnitude of the Th1 response, and the degree of Th1 cell terminal differentiation, were comparable in WT, IL-10R1⁻/⁻ and IL-10⁻/⁻ mice and the numbers and phenotype of Foxp3⁺ cells were largely unaltered in WSX-1⁻/⁻ mice during infection. As expected, depletion of Foxp3⁺ cells did not enhance Th1 cell polarisation or terminal differentiation during malaria infection. Our results significantly expand our understanding of how IL-27 regulates Th1 responses in vivo during inflammatory conditions and establishes WSX-1 as a critical and non-redundant regulator of the emergent Th1 effector response during malaria infection.

Combined N-of-1 trials to investigate mexiletine in non-dystrophic myotonia using a Bayesian approach; study rationale and protocol.

BACKGROUND: To obtain evidence for the clinical and cost-effectiveness of treatments for patients with rare diseases is a challenge. Non-dystrophic myotonia (NDM) is a group of inherited, rare muscle diseases characterized by muscle stiffness. The reimbursement of mexiletine, the expert opinion drug for NDM, has been discontinued in some countries due to a lack of independent randomized controlled trials (RCTs). It remains unclear however, which concessions can be accepted towards the level 1 evidence needed for coverage decisions, in rare diseases. Considering the large number of rare diseases with a lack of treatment evidence, more experience with innovative trial designs is needed. Both NDM and mexiletine are well suited for an N-of-1 trial design. A Bayesian approach allows for the combination of N-of-1 trials, which enables the assessment of outcomes on the patient and group level simultaneously. METHODS/DESIGN: We will combine 30 individual, double-blind, randomized, placebo-controlled N-of-1 trials of mexiletine (600 mg daily) vs. placebo in genetically confirmed NDM patients using hierarchical Bayesian modeling. Our results will be compared and combined with the main results of an international cross-over RCT (mexiletine vs. placebo in NDM) published in 2012 that will be used as an informative prior. Similar criteria of eligibility, treatment regimen, end-points and measurement instruments are employed as used in the international cross-over RCT. DISCUSSION: The treatment of patients with NDM with mexiletine offers a unique opportunity to compare outcomes and efficiency of novel N-of-1 trial-based designs and conventional approaches in producing evidence of clinical and cost-effectiveness of treatments for patients with rare diseases. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02045667.

A novel role for IL-27 in mediating the survival of activated mouse CD4 T lymphocytes.

IL-27, an IL-12 family cytokine, has pleiotropic functions in the differentiation and expansion of CD4(+) T cell subsets. In this study, we discovered a novel function of IL-27. CD4(+)CD45RB(high) T cells from mice deficient for the α-chain of IL-27 receptor failed to induce colitis in Rag(-/-) recipients, because of an inability of activated donor cells to survive. Interestingly, IL-27 was indispensable for the prevention of colitis by regulatory T cells, also because of a defect in long-term cell survival. IL-27 affected the survival of activated T lymphocytes, rather than promoting cell proliferation, by inhibiting Fas-mediated activation-induced T cell death, acting through the STAT3 signaling pathway. The addition of IL-27 during activation resulted in an increased cell number, which was correlated with decreased activation of both caspases 3 and 8. This prosurvival effect was attributed to downregulation of FasL and to the induction of the antiapoptotic protein cFLIP. Although activation induced cell death is an important mechanism for the maintenance of immunological homeostasis, protection of lymphocytes from excessive cell death is essential for effective immunity. Our data indicate that IL-27 has a crucial role in the inhibition of activation-induced cell death, thereby permitting Ag-driven T cell expansion.