Pediatric autoimmune encephalitis in Denmark during 2011-17: A nationwide multicenter population-based cohort study.

BACKGROUND: The incidence of pediatric autoimmune encephalitis (AIE) is unknown. Our aim was to assess the incidence of pediatric AIE in Denmark 2011-17. METHODS: In a nationwide population-based setting, we retrieved data on all children tested for AIE before age 18 years. We reviewed medical records in a) children with AIE antibodies (n = 18) to assess whether children fulfilled the AIE consensus criteria, b) children tested negative for AIE antibodies who were registered with an AIE diagnostic code to estimate the incidence of "antibody negative but probable AIE", and c) a reference cohort (n = 596) to determine the positive predictive value of International Classification of Diseases (ICD) codes used for anti-NMDAR encephalitis. RESULTS: 375 children were tested for AIE 2011-17 (median age 11.1 years; 54% girls); 18 children (5%) had AIE antibodies (percentage tested positive): CSF GAD65-IgG (3.1%), plasma NMDAR-IgG (2.8%), CSF NMDAR-IgG (1.8%), plasma GAD65-IgG (1.0%), and plasma CASPR2-IgG (0.4%). Five children fulfilled the criteria for probably/definite anti-NMDAR encephalitis (incidence: 0.07/100,000 person-years; 95% CI = 0.03-0.17), and 4 children with anti-GAD65 associated AIE (incidence = 0.055/100,000 person-years, 95% CI = 0.021-0.15). The incidence of "antibody negative but probable AIE" was 0.055/100,000 person-years (95% CI = 0.021-0.15). The positive predictive value of ICD diagnostic codes used for anti-NMDAR encephalitis was 8%. CONCLUSIONS: We diagnosed only children with anti-NMDAR, anti-GAD65, and "antibody negative but probable AIE". Before examining AIE antibodies, clinical presentation, paraclinical studies (CSF, EEG, and MRI), and incidence of pediatric AIEs should be considered. Updating the ICD to include AIE codes is warranted.

Diagnostic Value of Oligoclonal Bands in Children: A Nationwide Population-Based Cohort Study.

OBJECTIVE: We evaluated the diagnostic value of cerebrospinal fluid oligoclonal bands in individuals less than 18 years of age. METHODS: In a nationwide population-based setting, we retrieved data on 2055 children's oligoclonal band examination, including concordant cerebrospinal fluid biomarkers, during 1994 to 2017. Case ascertainment was by review of medical records and diagnostic codes. We used Fisher's exact test to explore distribution differences of oligoclonal band positivity in acquired demyelinating syndromes (ADS) before and after age 12 years and calculated the sensitivity, specificity, positive predictive value, and negative predictive value of oligoclonal bands to distinguish ADS from the other diagnostic groups. RESULTS: Median age at oligoclonal band examination was 15.2 years (range = 1.8 to 18.0), and 10% had presence of cerebrospinal fluid oligoclonal bands. Oligoclonal band positivity was the highest in ADS (52%), but it was age dependent: 21% in children with ADS before age 12 years and 68% in children aged 12 through 17 years (P < 0.0001) owing to the higher incidence of multiple sclerosis in the latter. Cerebrospinal fluid oligoclonal bands were not predictive of ADS before age 12 years compared with the other diagnostic groups. However, cerebrospinal fluid oligoclonal bands in children aged 12 through 17 years were highly predictive of ADS compared with central nervous system infections and non-ADS immune-mediated central nervous system diseases (positive predictive value: 0.89; 95% confidence interval = 0.82 to 0.94; P < 0.0001), but negative oligoclonal bands were not discriminatory (negative predictive value: P = 0.17). CONCLUSIONS: In a clinical setting, cerebrospinal fluid oligoclonal band examination may be of higher yield in children aged 12 through 17 years if there is clinical suspicion of multiple sclerosis, and in such circumstances a positive test supports a diagnosis of multiple sclerosis.

Nationwide prevalence and incidence study of neuromyelitis optica spectrum disorder in Denmark.

OBJECTIVES: To estimate the nationwide population-based incidence, prevalence, and geographical distribution of neuromyelitis optica (NMO) spectrum disorder (NMOSD) in Denmark based on the 2015 International Panel for NMO Diagnosis (IPND) criteria. METHODS: We conducted a multicentre, historically prospective study. Data were sourced from the Danish National Patient Registry, the Danish Multiple Sclerosis Registry, departments of neurology, and laboratories providing aquaporin-4 antibody test. Cases were selected based on the 2006 Wingerchuk and the 2015 IPND criteria and were individually validated by an expert panel. RESULTS: We confirmed NMO in 30 cases (2006 criteria) and NMOSD in 56 cases (2015 IPND criteria) between 2007 and 2014. Defined by the 2006 criteria, the incidence of NMO was 0.029 per 100,000 person-years (95% confidence interval [CI] 0.014-0.051), and the prevalence (aged 16 years and older) was 0.566 per 100,000 (95% CI 0.370-0.830). Based on the 2015 IPND criteria, the incidence of NMOSD was 0.070 per 100,000 person-years (95% CI 0.046-0.102), and the prevalence (aged 16 years and older) was 1.09 per 100,000 (95% CI 0.808-1.440), without regional differences. CONCLUSIONS: Our estimates of incidence and prevalence are similar to other Caucasian population-based studies using the 2015 IPND criteria. We found no geographical clustering in Denmark.

A low-gluten diet induces changes in the intestinal microbiome of healthy Danish adults.

Adherence to a low-gluten diet has become increasingly common in parts of the general population. However, the effects of reducing gluten-rich food items including wheat, barley and rye cereals in healthy adults are unclear. Here, we undertook a randomised, controlled, cross-over trial involving 60 middle-aged Danish adults without known disorders with two 8-week interventions comparing a low-gluten diet (2 g gluten per day) and a high-gluten diet (18 g gluten per day), separated by a washout period of at least six weeks with habitual diet (12 g gluten per day). We find that, in comparison with a high-gluten diet, a low-gluten diet induces moderate changes in the intestinal microbiome, reduces fasting and postprandial hydrogen exhalation, and leads to improvements in self-reported bloating. These observations suggest that most of the effects of a low-gluten diet in non-coeliac adults may be driven by qualitative changes in dietary fibres.

Adrenal insufficiency is seen in more than one-third of patients during ongoing low-dose prednisolone treatment for rheumatoid arthritis.

OBJECTIVE: Patients receiving long-term glucocorticoid treatment are at risk of developing adrenal insufficiency during treatment. We investigated the prevalence of prednisolone-induced adrenal insufficiency in the particular clinical situation where patients receive ongoing low-dose (5 mg/day) prednisolone treatment, a dose by itself too low to cover glucocorticoid needs during stress. DESIGN AND METHODS: Cross-sectional study in 42 patients with rheumatoid arthritis (29 women, aged 36-86 years) treated with 5 mg prednisolone/day, who had received prednisolone for ≥6 months (median: 66, range: 6-444 months). Adrenal function was evaluated by a 250 µg Synacthen test performed after mean 48.7 h prednisolone pause. Local assay-specific cut-off for normal adrenal function was P-cortisol ≥420 nmol/L 30 min after Synacthen injection. RESULTS: Overall, 20 of the 42 patients (48%, 95% CI: 33-62%) had an insufficient adrenal response to the Synacthen test. Including only patients who had not received concomitant treatment with any other glucocorticoid formulas within the last 3 months, 13 of 33 patients (39%, 95% CI: 25-56%) had an insufficient response. Adrenocorticotrophic hormone (ACTH) concentrations were generally low and anti-adrenal antibodies were negative indicating secondary adrenal insufficiency as the most likely diagnosis. There was no correlation between duration of treatment and 30 min P-cortisol (P = 0.62). Adrenal function did not depend on sex or seropositivity of rheumatoid arthritis. CONCLUSION: We demonstrate a high prevalence of adrenal insufficiency during ongoing low-dose prednisolone treatment. The results urge to increase focus on the condition to ensure identification and correct management of insufficient patients during stress and withdrawal. Strategies for adrenal function evaluation during ongoing low-dose glucocorticoid treatment need to be established.

[Myopathy in a patient during simvastatin and fluconazole treatment].

A 69-year-old female was admitted due to progressive loss of muscle strength following addition of fluconazole to long-term simvastatin treatment. Rhabdomyolysis was suspected and both drugs were discontinued. Forced diuresis was initiated together with a short course of prednisolone. After 21 weeks the patient had regained normal muscle strength and endurance. The favourable course and the absence of antibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase suggest that the condition was due to interaction between the two drugs, which are both metabolized via the CYP3A4 pathway.

A novel index for preoperative, non-invasive prediction of macro-radical primary surgery in patients with stage IIIC-IV ovarian cancer-a part of the Danish prospective pelvic mass study.

The purpose of this study was to develop a novel index for preoperative, non-invasive prediction of complete primary cytoreduction in patients with FIGO stage IIIC-IV epithelial ovarian cancer. Prospectively collected clinical data was registered in the Danish Gynecologic Cancer Database. Blood samples were collected within 14 days of surgery and stored by the Danish CancerBiobank. Serum human epididymis protein 4 (HE4), serum cancer antigen 125 (CA125), age, performance status, and presence/absence of ascites at ultrasonography were evaluated individually and combined to predict complete tumor removal. One hundred fifty patients with advanced epithelial ovarian cancer were treated with primary debulking surgery (PDS). Complete PDS was achieved in 41 cases (27 %). The receiver operating characteristic curves demonstrated an area under the curve of 0.785 for HE4, 0.678 for CA125, and 0.688 for age. The multivariate model (Cancer Ovarii Non-invasive Assessment of Treatment Strategy (CONATS) index), consisting of HE4, age, and performance status, demonstrated an AUC of 0.853. According to the Danish indicator level, macro-radical PDS should be achieved in 60 % of patients admitted to primary surgery (positive predictive value of 60 %), resulting in a negative predictive value of 87.5 %, sensitivity of 68.3 %, specificity of 83.5 %, and cutoff of 0.63 for the CONATS index. Non-invasive prediction of complete PDS is possible with the CONATS index. The CONATS index is meant as a supplement to the standard preoperative evaluation of each patient. Evaluation of the CONATS index combined with radiological and/or laparoscopic findings may improve the assessment of the optimal treatment strategy in patients with advanced epithelial ovarian cancer.

Non-specific binding in solid phase immunoassays for autoantibodies correlates with inflammation markers.

Enzyme-linked immunosorbent assay (ELISA) is a validated and sensitive method for detection of human autoantibodies, but may have problems with specificity. Non-specific binding is a well-known problem often observed in tests for autoantibodies, when sera are incubated on plastic surfaces, e.g. an ELISA plate. To understand the mechanisms underlying non-specific immunoglobulin deposition, we here analyse the phenomenon in detail and we propose means of reducing false positive test results caused by non-specific binding. The level of non-specific binding, in sera with suspected autoreactivity, was analysed in non-coated and autoantigen-coated ELISA wells and 4-32% of sera showed a high level of non-specific binding depending on the assay conditions and serum properties. Non-specifically binding sera were found to contain increased concentrations of IgG and other inflammatory mediators. Moreover, non-specific binding could be induced in serum by increasing the concentration of IgG and incubating the serum at 40 °C. This suggests that non-specific binding immunoglobulins can be formed during inflammation with high immunoglobulin levels and elevated temperature. We show that the level of non-specific binding correlates with the IgG concentration and therefore propose that non-specific binding may be interpreted as an informative finding indicative of elevated IgG and inflammation.