Bihormonal fully closed-loop system for the treatment of type 1 diabetes: a real-world multicentre, prospective, single-arm trial in the Netherlands.

BACKGROUND: Management of insulin administration for intake of carbohydrates and physical activity can be burdensome for people with type 1 diabetes on hybrid closed-loop systems. Bihormonal fully closed-loop (FCL) systems could help reduce this burden. In this trial, we assessed the long-term performance and safety of a bihormonal FCL system. METHODS: The FCL system (Inreda AP; Inreda Diabetic, Goor, Netherlands) that uses two hormones (insulin and glucagon) was assessed in a 1 year, multicentre, prospective, single-arm intervention trial in adults with type 1 diabetes. Participants were recruited in eight outpatient clinics in the Netherlands. We included adults with type 1 diabetes aged 18-75 years who had been using flash glucose monitoring or continuous glucose monitors for at least 3 months. Study visits were integrated into standard care, usually every three months, to evaluate glycaemic control, adverse events, and person-reported outcomes. The primary endpoint was time in range (TIR; glucose concentration 3·9-10·0 mmol/L) after 1 year. The study is registered in the Dutch Trial Register, NL9578. FINDINGS: Between June 1, 2021, and March 2, 2022, we screened 90 individuals and enrolled 82 participants; 78 were included in the analyses. 79 started the intervention and 71 were included in the 12 month analysis. Mean age was 47.7 (SD 12·4) years and 38 (49%) were female participants. The mean preintervention TIR of participants was 55·5% (SD 17·2). After 1 year of FCL treatment, mean TIR was 80·3% (SD 5·4) and median time below range was 1·36% (IQR 0·80-2·11). Questionnaire scores improved on Problem Areas in Diabetes (PAID) from 30·0 (IQR 18·8-41·3) preintervention to 10·0 (IQR 3·8-21·3; p<0·0001) at 12 months and on World Health Organization-Five Well-Being Index (WHO-5) from 60·0 (IQR 44·0-72·0) preintervention to 76·0 (IQR 60·0-80·0; p<0·0001) at 12 months. Five serious adverse events were reported (one cerebellar stroke, two severe hypoglycaemic, and two hyperglycaemic events). INTERPRETATION: Real-world data obtained in this trial demonstrate that use of the bihormonal FCL system was associated with good glycaemic control in patients who completed 1 year of treatment, and could help relieve these individuals with type 1 diabetes from making treatment decisions and the burden of carbohydrate counting. FUNDING: Inreda Diabetic.

Monitoring patients with celiac disease on gluten free diet: different outcomes comparing three tissue transglutaminase IgA assays.

OBJECTIVES: Tissue transglutaminase (tTG) IgA antibodies are a hallmark for celiac disease (CD). In CD patients on gluten free diet (GFD) these antibodies are transient. Few studies are available comparing the tTG-IgA assay characteristics for monitoring response to GFD. Since discrepant results were reported in patients on GFD after switching tTG-IgA assays, we conducted a retrospective observational study to monitor GFD response using three different tTG-IgA assays. METHODS: Diagnostic samples from 44 adults and 17 children with CD were included. Of most patients two follow-up samples after introduction of GFD were available. In all samples tTG-IgA were assessed using one fluorochrome-enzyme immuno-assay (FEIA) and two chemiluminescence immuno-assays (CLIA) and intestinal fatty acid binding protein (i-FABP) as surrogate marker for intestinal epithelial damage was measured. RESULTS: Using CLIA assays, normalization of antibody levels was delayed compared to FEIA (p<0.001). Of all samples taken after at least 6 months on GFD with elevated i-FABP indicating intestinal epithelial damage, 40 % had positive tTG-IgA according to the FEIA, 85 and 90 % according to the two CLIA. CONCLUSIONS: Normalization of tTG-IgA in patients on GFD depends on the assay used. Both CLIA appear to be more sensitive in detecting suboptimal treatment response in CD-indicated by elevated i-FABP - when applying the manufacturer's recommended cut-off for the diagnosis of CD.

Multicenter study to compare the diagnostic performance of CLIA vs. FEIA transglutaminase IgA assays for the diagnosis of celiac disease.

OBJECTIVES: Celiac disease (CD) is an immune-mediated enteropathy driven by gluten intake. Presence of tTG-IgA antibodies is important for the diagnosis. However, different tTG-IgA assays are used and test performance may vary. Therefore, a retrospective multicenter study was performed to compare the diagnostic performance of three assays. METHODS: The fluorescence enzyme-linked immunoassay (FEIA) EliA Celikey IgA (Phadia), the chemiluminescence immunoassays (CLIA) h-tTG IgA QUANTA Flash® (Inova Diagnostics) and the anti-tTG ChLIA IgA (Euroimmun) were compared. Diagnostic samples from CD cases (95 adults; 65 children) and controls (479 adults; 253 children) were included. Samples were blinded and reanalyzed on all platforms. RESULTS: A high quantitative correlation between platforms was found (p<0.0001). Both CLIA were more sensitive (adults 100%; children 100%) compared to the FEIA (adults 88.4%; children 96.6%). Specificity of all assays was high (≥97.6%) with the FEIA having the highest specificity. A cut-off based on receiver operator characteristic analysis (6.5 U/mL) improved the sensitivity of the FEIA (adults 95.8%; children 100%) without affecting specificity. Cut-off values for the CLIA assays did not need further optimization. With the FEIA, 71% of pediatric cases had a tTG-IgA level ≥10× upper limit of normal compared to 91 and 92% with QUANTA Flash and ChLIA, respectively. CONCLUSIONS: All platforms have high diagnostic accuracy. The CLIA assays are more sensitive compared to the FEIA assay. A lower cut-off for the FEIA improves diagnostic performance, particularly in adult cases that, as demonstrated in this study, present with lower tTG-IgA levels compared to pediatric cases.

Experiences from 4 Years of Organization of an External Quality Assessment for Mycobacterium tuberculosis Whole-Genome Sequencing in the European Union/European Economic Area.

Here, we report the development and key features of the first external quality assessment (EQA) scheme for Mycobacterium tuberculosis whole-genome sequencing (WGS). The results of four rounds (2017 to 2020) of implementation within the European tuberculosis reference laboratories network (ERLTB-Net-2) are presented and discussed. EQA panels comprising 10 genomic DNAs were distributed to ERLTB-Net 2 laboratories volunteering to participate in this exercise. Since 2018, five FASTQ files were added to better assess the dry WGS processes, and in 2020, three of the five files were replaced by synthetic files (providing additional flexibility for the mutations included in the panels). Ten National tuberculosis reference laboratories participated in all four EQA rounds, and seven participated in at least one. High-confidence resistance mutations were correctly identified by all laboratories, but challenges remained with respect to the identification of mixed loci and interpretation of rare mutations. M. tuberculosis genotyping and clustering analysis was >90% accurate for pure samples with the main challenges being related to the analysis of mixed genotypes and DNA FASTQ files. The development and implementation of this WGS EQA scheme has contributed to the continuous improvement in performance of participating laboratories in M. tuberculosis WGS and data analysis. This scheme can serve as a model of comprehensive quality assessment for M. tuberculosis WGS that can be replicated in different settings worldwide. IMPORTANCE The wider availability of whole-genome sequencing (WGS) coupled to new developments in bioinformatic tools and databases to interpret Mycobacterium tuberculosis complex WGS data has accelerated the adoption of this method for the routine prediction of antimycobacterial drug resistance and genotyping, thus necessitating the establishment of a comprehensive external quality control system. Here, we report 4 years of development and results from such a panel.

[Care for adolescents with an autism spectrum disorder and an intellectual disability]. / Zorg voor adolescenten met autisme en een verstandelijke beperking.

BACKGROUND: Due to an experienced gap in care for adolescents with an autism spectrum disorder (ASD) and an intellectual disability (ID), an interdisciplinary outpatient clinic was initiated by child- and adolescent psychiatry services together with intellectual disability physicians in the Rotterdam region in 2017. AIM: Evaluation of the ASD-ID outpatient clinic. METHOD: A retrospective chart review study of the first year of the ASD-ID outpatient clinic was performed. The care specific traits of the adolescents who visited the ASD-ID outpatient clinic, their health care costs and the effect of the ASD-ID outpatient clinic on both the health care costs and the patient outflow was compared to the traits of the adolescents of the autism outpatient clinic. RESULTS: 32 adolescents who were referred to the ASD-ID outpatient clinic were comparable to 204 adolescents of the autism outpatient clinic in age (mean 16.5 years) and gender (75% male). They had 39% more DSM-IV classifications, were in care 3.7 years longer and had 44% more health care costs. After visiting the ASD-ID outpatient clinic, 50% of the adolescents were transferred within a year and 100% within three years to a intellectual disability physician. CONCLUSION: Adolescents with ASD and ID are a group with a substantial demand for care who deserve specific attention. An integrated ASD-ID outpatient clinic contributes to this demand.

External quality assessment of flow cytometric bronchoalveolar lavage cellular analysis: 20 years' experience in The Netherlands.

BACKGROUND: Bronchoalveolar (BAL) cellular analysis can be supportive in the diagnosis of interstitial lung disease. The flow cytometric analysis of BAL fluid cells is complicated by cell fragility and adherence and autofluorescence of macrophages, making conventional analysis of BAL fluid cells as done in external quality schemes (EQA) for blood lymphocyte subsets, not representative. Following a procedure for stabilized BAL cells, a separate EQA was set up. The results of 20 years' experience are presented. METHODS: From each round between 2000 and 2020 the following flow cytometric parameters were recorded from each participant: total lymphocyte population (TLY), CD3+ lymphocytes, CD3+ CD4+ lymphocytes, CD3+ CD8+ lymphocytes, CD3- CD16+/56+ lymphocytes, CD19+ lymphocytes and CD103 + CD3+ lymphocytes. In addition, the eosinophils and neutrophils were recorded. The mean and standard deviation of each parameter per round were calculated. The 40 rounds were divided in four respective groups of 10 in order to compare the results as function of time. In addition the interpretation of the results of participants was scored. RESULTS: The median SD in the four groups was below 10% for all parameters except for TLY and the CD103+ CD3+ lymphocytes. No improvement in time was observed for any (sub)population except for the CD3+ CD4+ subset. Interpretation of the results varied based on disease, with greatest consensus for sarcoidosis cases and lowest for nonspecific interstitial lung disease cases. CONCLUSIONS: A dedicated EQA for BAL fluid cellular analysis appears to be justified as the test material is substantially different from that of peripheral blood. We show that adequate analytical and post-analytical quality control can be achieved.

Impact of Preanalytical Factors on Calprotectin Concentration in Stool: A Multiassay Comparison.

BACKGROUND: Measuring calprotectin concentration in stool is increasingly important in monitoring disease activity and treatment response in inflammatory bowel disease. This study evaluates the impact of preanalytical storage conditions on reliability of calprotectin testing using 5 different calprotectin immunoassays. METHODS: Aliquots of homogenized fresh fecal samples in untreated or extracted form were stored at room temperature or 4°C. Calprotectin concentration was measured day 0 to 4 and 8. Five different immunoassays and accompanying extraction buffers were used (CALiaGold, Phadia EliA, Bühlmann fCal turbo, ELISA Bühlmann, Inova Quanta Flash). Repeated measurements of change from baseline calprotectin levels over time were analyzed using a mixed model analysis. RESULTS: Calprotectin concentrations declined over time under all preanalytical conditions with all assays, except for extracted feces stored at 4°C. The rate of decline was greatest in untreated stool kept at room temperature, reaching significant difference from baseline already after 1 day (P < 0.001). In extracted feces kept at room temperature, significant difference from baseline was reached after 2 days, and in untreated feces at 4°C, after 4 days. However, the results differed significantly between assays. After 4 days of storage at room temperature, the mean calprotectin decline from baseline differed between 30% and 60%, dependent on the assay used. CONCLUSIONS: Fecal calprotectin concentration in stool samples declines over time, and the rate of decline is greater at higher temperatures. In extracted feces stored at 4°C, calprotectin is most stable. It is assay-dependent how long extracted feces stored at 4°C give reliable test results.

High throughput surface plasmon resonance imaging method for clinical detection of presence and strength of binding of IgM, IgG and IgA antibodies against SARS-CoV-2 during CoViD-19 infection.

Surface Plasmon Resonance imaging (SPRi) was used to determine the presence and strength of binding of IgG, IgM and IgA against the Receptor Binding Domain (RBD) of SARS-CoV-2 in sera of 102 CoViD-19 and non-CoViD-19 patients. The SPRi assay simultaneously measures the antibody isotype levels and the strength of binding to the RBD of ultimate 384 patient samples in one run. It turns out that during the course of the disease, the IgG levels and strength of binding increased while generally the IgM and IgA levels go down. Recovered patients all show high strength of binding of the IgG type to the RBD protein. The anti-RBD immunoglobulins SPRi assay provides additional insights in the immune status of patients recovering from CoViD-19. This new high throughput method can be applied for the assessment of the quality of the immune reaction of healthy individuals to SARS-CoV-2 and its mutants in vaccination programs.•Surface Plasmon Resonance imaging is an unprecedented technology for high throughput screening of antibody profiling of CoViD19 patients.•Fingerprinting of isotypes IgM, IgG and IgA can be performed for 384 patients in one run.•An affinity maturation effect was shown for patients recovering from CoViD19.

Presence and strength of binding of IgM, IgG and IgA antibodies against SARS-CoV-2 during CoViD-19 infection.

Surface Plasmon Resonance imaging (SPRi) was used to determine the presence and strength of binding of IgG, IgM and IgA against the Receptor Binding Domain (RBD) of SARS-CoV-2 in sera of 119 CoViD-19 patients. The SPRi assay measures the antibody isotype levels and the strength of binding to the RBD of ultimate 384 patient samples in one run. It turns out that during the course of the disease, the IgG levels and strength of binding increased while generally the IgM and IgA levels go down. Recovered patients all show high strength of binding of the IgG type to the RBD protein. The anti-RBD immunoglobulins SPRi assay provides additional insights in the immune status of patients recovering from CoViD-19 and this new method can furthermore be applied for the assessment of the quality of the immune reaction of healthy individuals to SARS-CoV-2 in vaccination programs.

Comparison of three methods to stabilize bronchoalveolar lavage cells for flowcytometric analysis.

BACKGROUND: Flowcytometric analysis of lymphocytes and their subpopulations in bronchoalveolar lavages (BAL) can support the diagnosis of interstitial lung diseases. This analysis should be done within 4 hr after lavage due to rapid cell deterioration. We tested three methods in order to stabilize for at least 28 days the BAL cell populations to allow delayed flowcytometric analysis in order to facilitate external quality assurance (EQA). METHODS: We compared an in-house, dual-step stabilization method for BAL cells with results of two different commercial available stabilization reagents: TransFix® and Streck Cell Preservative™. All three methods were compared with native BAL cells as reference. BAL samples from six patients were tested on six occasions following stabilization from 1 to 28 days by flow cytometry. RESULTS: Following stabilization and storage at 4°C, BAL cell suspensions had stable light scatter patterns and lymphocyte subsets. As expected, rapid deterioration of cells was seen with native BAL cells. The stabilized lavages showed more stable counts of WBC and lymphocyte populations with only minor differences found between the three methods. CONCLUSIONS: If analysis of the BAL cells is performed more than 24 hr after the lavage, stabilized BAL cells are superior to native cells. The in-house method can be used for EQA purposes with stability for at least 28 days. The TransFix and Streck methods might be useful for postponed diagnostic analysis of lavage cells but did not meet our 28 days criterion defined needed for EQA purposes.

Surfactant use in late preterm infants: a survey among Belgian neonatologists.

Specific recommendations on surfactant administration in late preterm (LPT) infants with pulmonary disease are lacking. We performed an online-based, nationwide survey amongst all (n = 102) Belgian neonatologists to identify the use of surfactant in LPT infants suffering from several respiratory pathologies. The survey used clearly defined clinical cases and resulted in a 86% response rate. Neonatologists adhere to the 200 mg/kg initial surfactant dosing scheme. Surfactant is widely used in respiratory distress syndrome (70.1%), but there is less unanimity on its use in meconium aspiration syndrome (58.0%), transient tachypnoea of the newborn (30.6%), congenital pneumonia (27.2%) and congenital diaphragmatic hernia (8.6%). Respondents adhere to the European guideline of a timely referral to a newborn intensive care unit (non-invasive ventilation and FiO2 > 0.30 at 12 h of age), in order to minimise the risk of deterioration.Conclusion: We demonstrate a wide variety in the use of surfactant within LPT infants. The majority of Belgian neonatologists therefore urge for an investment in multi-centre trials on surfactant administration in LPT infants, in order to create an evidence-based practice as well as to reduce the strain on health care budgets.Trial registration: https://clinicaltrials.gov What is Known: • Any late preterm (LPT) infant with respiratory distress needs a timely referral to a neonatal intensive care unit in case of non-invasive ventilation and FiO2 > 0.30 at 12 h of life, in order to minimise the risk of acute deterioration as well as chronic lung disease. • Any modest increase in morbidity in the sizeable group of LPT infants exerts a significant strain on health care budgets. What is New: • We report the attitudes and opinions of Belgian neonatologists about the use of surfactant in LPT infants suffering from several respiratory diseases. • Our survey demonstrates a significant variability in practice between neonatologists during treatment of respiratory pathologies in LPT infants. This highlights an urgent need for univocal therapeutic lines.

[Image of the month: Severe hydrocephalus in a child withcongenitalmyotonic dystrophy X]. / L'image du mois : Hydrocéphalie sévère chez un enfant avec dystrophie myotonique congénitale.

Severe hydrocephalus in a child with congenital myotonic dystrophy X A young patient with congenital myotonic dystrophy, or Steinert's disease, presented at the age of 4.5 months with an increase of his head circumference and signs of intracranial hypertension. The results of the radiological exams reveal a major hydrocephalus. The patient condition evolved favourably after ventriculoperitoneal bypass. While ventriculomegaly is common in congenital myotonic dystrophy, hydrocephalus with signs of intracranial hypertension is rare, hence the need of regular monitoring of head circumference.

Un jeune patient atteint de dystrophie myotonique congénitale, ou maladie de Steinert, présente, à l'âge de 4 mois et demi, un décrochage de son périmètre crânien et des signes d'hypertension intracrânienne. Le bilan radiologique révèle une hydrocéphalie majeure. L'enfant évolue favorablement après dérivation ventriculopéritonéale. Alors que la ventriculomégalie est fréquente lors d'une dystrophie myotonique congénitale, l'hydrocéphalie avec signes d'hypertension intracrânienne est rare, d'où la nécessité d'un suivi régulier du périmètre crânien.

Spatial Effects of Livestock Farming on Human Infections With Shiga Toxin-Producing Escherichia coli O157 in Small but Densely Populated Regions: The Case of the Netherlands.

The role of environmental transmission of typically foodborne pathogens like Shiga toxin-producing Escherichia coli (STEC) O157 is increasingly recognized. To gain more insights into spatially restricted risk factors that play a role in this transmission, we assessed the spatial association between sporadic STEC O157 human infections and the exposure to livestock (i.e. small ruminants, cattle, poultry, and pigs) in a densely populated country: the Netherlands. This was done for the years 2007-2016, using a state-of-the-art spatial analysis method in which hexagonal areas with different sizes (90, 50, 25 and 10 km2) were used in combination with a novel probability of exposure metric: the population-weighted number of animals per hexagon. To identify risk factors for STEC O157 infections and their population attributable fraction (PAF), a spatial regression model was fitted using integrated nested Laplace approximation (INLA). Living in hexagonal areas of 25, 50 and 90 km2 with twice as much population-weighted small ruminants was associated with an increase of the incidence rate of human STEC O157 infections in summer (RR of 1.09 [95%CI;1.01-1.17], RR of 1.17 [95%CI;1.07-1.28] and RR of 1.13 [95%CI;1.01-1.26]), with a PAF of 49% (95%CI;8-72%). Results suggest exposure to small ruminants to be a risk factor, although no evidence on the mode of transmission is provided. Therefore, the underlying mechanisms warrant further investigation and could offer new targets for control. The newly proposed exposure metric has potential to improve existing spatial modeling studies on infectious diseases related to livestock exposure, especially in densely populated countries like the Netherlands.

Pyloric outflow obstruction secondary to sclerosing encapsulating peritonitis in a dog.

A 6-year-old, male neutered mixed breed dog was presented emergently with a three-week history of hyporexia, vomiting, diarrhoea and weight loss. Upon examination, the patient was dull, had generalised muscle atrophy, moderate abdominal pain and a mild amount of peritoneal effusion. A fluid-filled, distended, corrugated small bowel with marked gastroparesis and moderate peritoneal effusion was noted on abdominal ultrasonography. Endoscopy revealed hyperaemic and friable mucosa and a subjectively narrowed pylorus. Emergency exploratory celiotomy was performed due to worsening patient condition and revealed thick, diffuse, fibrous adhesions of the abdominal cavity. Based on these findings, sclerosing encapsulating peritonitis (SEP) was suspected. A large mass of omentum adjacent to the greater curvature of the stomach had caused a pyloric outflow obstruction. Adhesiolysis was attempted but was unsuccessful due to the friability of the small intestines. The dog was humanely euthanased under anaesthesia. A diagnosis of SEP was confirmed via necropsy. No underlying cause was identified. This is the first known case of a pyloric outflow obstruction secondary to SEP in a dog. Although rare, this condition should be considered as a differential for dogs with signs of a pyloric outflow obstruction with concurrent ascites and abdominal pain, hyporexia, vomiting and diarrhoea.

[Listeria monocytogenes sepsis. Fatal course in an immunocompetent child]. / Sepsis à Listeria monocytogenes Issue fatale chez un enfant immunocompétent.

The occurrence of non-viral meningitis remains a heavy diagnosis carrying undeniable pejorative aspects that may vary according to several factors such as the age and the presence or absence of an immunodeficiency. In some cases, uncommon germs can also lead to a bad prognosis such as Listeria monocytogenes that can be responsible of an extremely severe septic state. We report the case of a girl with Listeria meningitis, whose evolution was unfortunately quickly negative.

La survenue d'une méningite reste, à l'exception de la plupart des méningites virales, un diagnostic lourd, comportant un aspect péjoratif incontestable et source d'inquiétude pour les familles. Ce caractère péjoratif peut, toutefois, varier en fonction de certains éléments cliniques, tels que l'âge de l'enfant, la présence ou non d'une immunodéficience ou d'autres facteurs favorisants. Le type de germe incriminé ainsi que sa virulence jouent aussi un rôle incontestable. Nous rapportons le cas d'une petite fille, sans antécédents médicaux, atteinte d'une méningite à Listeria monocytogenes dont l'évolution fut malheureusement rapidement fatale.

Sensor based eating time variables of dairy cows in the transition period related to the time to first service.

In dairy cattle, reproductive diseases and infertility are some of the most important reasons for culling, where postpartum negative energy balance (NEB) reduces reproductive performance. This single cohort observational study reports the association between eating time and the interval between calving and first service in 2036 dairy cows on 17 commercial farms in The Netherlands. Cows were equipped with a commercially available neck sensor (Nedap, Groenlo, The Netherlands), that measured the time cows spent eating, from 28 days (d) before until 28 d after parturition. Primiparous cows spent a mean of +45 minutes (min) eating time per day ante partum and +15 min eating time post partum more than multiparous cows. A Cox proportional hazard model was used to analyze eating time variables in relation to the interval between calving and first service. From 4 weeks before until 4 weeks after calving eating time variables per week were used. Weeks -4, -3 + 3 and +4 were used as weeks with stable eating time patterns and therefore the mean eating time per week and the standard deviation of the mean eating time per week were used. Weeks -2, -1, +1 and +2 were addressed as periods with unstable eating patterns and therefore the slope in eating time per week and the residual variance of the slope per week were modeled. Significant results were the mean eating time in week -4 and +3 where in both weeks higher eating time lead to a higher hazard for first service. Difference between primiparous and multiparous cows were also significant with a higher hazard for first service for primiparous cows. Week 4 post partum presented a significant difference between eating time of primiparous cows and multiparous cows. These results display how eating time variables in the transition period could be related to the interval between calving and first service, and that there is a relation between mean eating time in week -4, +3, +4 and the interval between calving and first insemination.

Frequencies and clinical associations of myositis-related antibodies in The Netherlands: A one-year survey of all Dutch patients.

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of connective tissue diseases, collectively known as myositis. Diagnosis of IIM is challenging while timely recognition of an IIM is of utter importance considering treatment options and otherwise irreversible (severe) long-term clinical complications. With the EULAR/ACR classification criteria (2017) considerable advancement has been made in the diagnostic workup of IIM. While these criteria take into account clinical parameters as well as presence of one autoantibody, anti-Jo-1, several autoantibodies are associated with IIM and are currently evaluated to be incorporated into classification criteria. As individual antibodies occur at low frequency, the development of line blots allowing multiplex antibody analysis has improved laboratory diagnostics for IIM. The Euroline myositis line-blot assay (Euroimmun) allows screening and semi-quantitative measurement for 15 autoantibodies, i.e. myositis specific antibodies (MSA) to SRP, EJ, OJ, Mi-2α, Mi-2ß, TIF1-γ, MDA5, NXP2, SAE1, PL-12, PL-7, Jo-1 and myositis associated antibodies (MAA) to Ku, PM/Scl-75 and PM/Scl-100. To evaluate the clinical significance of detection and levels of these autoantibodies in the Netherlands, a retrospective analysis of all Dutch requests for extended myositis screening within a 1 year period was performed. A total of 187 IIM patients and 632 non-IIM patients were included. We conclude that frequencies of MSA and MAA observed in IIM patients in a routine diagnostic setting are comparable to cohort-based studies. Weak positive antibody levels show less diagnostic accuracy compared to positive antibody levels, except for anti-NXP2. Known associations between antibodies and skin involvement (anti-MDA5, anti-TIF1-γ), lung involvement (anti-Jo-1), and malignancy (anti-TIF1-γ) were confirmed in our IIM study population. The availability of multiplex antibody analyses will facilitate inclusion of additional autoantibodies in clinical myositis guidelines and help to accelerate diagnosing IMM with rare but specific antibodies.

Falsely positive anti-glomerular basement membrane antibodies in a patient with hantavirus induced acute kidney injury - a case report.

BACKGROUND: Hantavirus infection is an uncommon cause of acute renal failure with massive proteinuria. Serology tests to support a presumptive diagnosis usually take a few days. During the initial work-up, autoimmune causes including anti-glomerular basement membrane (GBM) glomerulonephritis need to be excluded, because these require urgent therapy. In this case the delay in serological testing caused a dilemma in treatment initiation. CASE PRESENTATION: An 18-year-old patient was admitted to the hospital with acute renal failure, erythrocyturia and massive proteinuria. Routine blood analysis showed leucocytosis (40,5 × 109/l) and a serum creatinine of 233 µmol/l. Infectious causes, e.g. leptospirosis or hantavirus infection, or an autoimmune disease, e.g., AAV or anti-GBM glomerulonephritis was the most feasible underlying diagnosis. Before hantavirus serology results were known, anti-GBM antibodies were positive. Treatment for anti-GBM glomerulonephritis was withheld, because of the absence of other signs and symptoms of the disease and slight improvement of renal function. The diagnosis of acute hantavirus infection was later on confirmed, by seroconversion of a follow-up serum sample. Without further intervention renal function recovered and anti-GBM antibodies disappeared. CONCLUSION: Hantavirus infection may induce anti-GBM antibodies, falsely suggestive of anti-GBM glomerulonephritis. Anti-GBM antibodies are supposed to be 100% specific. No earlier reports of false positive anti-GBM titers were reported. Nevertheless, the anti-GBM antibodies in this case were seen as an innocent bystander effect. Considering the need of urgent initiation of plasmapheresis and administration of immunosuppressants it may lead to diagnostic dilemmas with crucial therapeutic consequences. Knowledge of this anomaly when diagnosing acute renal failure, is very important.