Calprotectin instability may lead to undertreatment in children with IBD

BACKGROUND: Treatment decisions in children with inflammatory bowel disease (IBD) are increasingly based on longitudinal tracking of faecal calprotectin concentrations, but there is little known about the stability of this protein in stool. METHODS: We stored aliquots of homogenised stool at room temperature and at 4°C, and measured the calprotectin concentration for 6 consecutive days with three different assays. In addition, we assessed calprotectin stability in assay-specific extraction buffers kept at room temperature. RESULTS: After 6 days of storage at room temperature, mean percentage change from baseline calprotectin concentrations in stool and extraction buffer was 35% and 46%, respectively. The stability of calprotectin was significantly better preserved in samples stored at 4°C (p=0.0066 and 0.0011, respectively). CONCLUSIONS: Calprotectin is not stable at room temperature. Children with IBD and their caretakers may be falsely reassured by low calprotectin values. The best advisable standard for preanalytical calprotectin handling is refrigeration of the stool sample until delivery at the hospital laboratory

Adiposity Blunts the Positive Relationship of Thyrotropin with Proprotein Convertase Subtilisin-Kexin Type 9 Levels in Euthyroid Subjects

BACKGROUND: Effects of thyroid function status on lipoprotein metabolism may extend into the euthyroid range. Low-density lipoprotein (LDL) metabolism is governed by proprotein convertase subtilisin-kexin type 9 (PCSK9), which down-regulates LDL receptor expression, resulting in higher LDL cholesterol (LDL-C). Here, we tested whether plasma PCSK9 correlates with thyroid function in nonobese and obese euthyroid subjects. METHODS: We assessed the extent to which plasma PCSK9 is determined by thyrotropin (TSH) in 74 euthyroid subjects (31 women; TSH between 0.5 and 4.0 mU/L and free thyroxine [FT4] between 11.0 and 19.5 pM) with varying degrees of obesity (body mass index [BMI] ranging from 20.2 to 40.4 kg/m(2)). RESULTS: TSH, FT4, PCSK9, non–high-density lipoprotein cholesterol (non-HDL-C), LDL-C, and apolipoprotein B (apoB) levels were not different between 64 nonobese subjects (BMI<30 kg/m(2)) and 10 obese subjects (BMI≥30 kg/m(2); p>0.20 for each). PCSK9 correlated positively with TSH in nonobese subjects (r=0.285, p=0.023). In contrast, PCSK9 was not associated positively with TSH in obese subjects (r=−0.249, p=0.49). The relationship of PCSK9 with TSH was different between nonobese and obese subjects when taking age, sex, FT4, and the presence of anti-thyroid antibodies into account (multiple linear regression analysis: β=−0.320, p=0.012 for the interaction term between the presence of obesity and TSH on PCSK9), and was also modified by BMI as a continuous trait (β=−0.241, p=0.062 for the interaction term between BMI and TSH on PCSK9). Non-HDL-C, LDL-C, and apoB levels were dependent on PCSK9 in nonobese subjects (p≤0.01 for each), but not in obese subjects (p>0.50), Accordingly, BMI interacted negatively with PCSK9 on non-HDL-C (p=0.028) and apoB (p=0.071). CONCLUSIONS: This study suggests that circulating PCSK9 levels correlate with thyroid function even in the normal range. This relationship appears to be blunted by obesity. Thyroid functional status may influence cholesterol metabolism through the PCSK9 pathway

Macro-B12 masking B12 deficiency

In clinical practice, the finding of an elevated serum B(12) concentration is often the consequence of supplementation with B(12) in either oral form or injections. Also, elevated serum B(12) may be associated with underlying disorders, like liver diseases or a (haematologic) malignancy. Only a few studies have shown that it may also be the consequence of complex formation of B(12)-vitamin binding proteins with immunoglobulins, the so-called macro-B(12). We describe a young woman who previously was diagnosed with B(12) deficiency, and in whom, after cessation of B(12) injection treatment, neurologic symptoms re-appeared, and despite this, repeatedly elevated serum B(12) concentrations above the upper limit of the assay were found. We demonstrated that this was caused by the presence of macro-B(12), which not only resulted in erroneous and longstanding elevated serum B(12), but also masked her underlying B(12) deficiency

Regulatory T Cells Facilitate Thymic Recovery After HSCT by Directly Enhancing Immigration of Donor Derived Thymic Progenitors

BACKGROUND & AIMS: An increasing number of physicians use repeated measurements of stool calprotectin to monitor intestinal inflammation in patients with inflammatory bowel diseases (IBDs). A lateral flow-based rapid test allows patients to measure their own stool calprotectin values at home. The test comes with a software application (IBDoc; Buhlmann Laboratories AG, Schonenbuch, Switzerland) that turns a smartphone camera into a results reader. We compared results from this method with those from the hospital-based reader (Quantum Blue; Buhlmann Laboratories AG) and enzyme-linked immunosorbent assay (ELISA) analysis. METHODS: In a single-center comparison study, we asked 101 participants (10 years of age or older) in the Netherlands to perform the IBDoc measurement on stool samples collected at home, from June 2015 to October 2016. Participants then sent the residual extraction fluid and a fresh specimen from the same bowel movement to our pediatric and adult IBD center at the University Medical Center Groningen, where the level of calprotectin was measured by the Quantum Blue reader and ELISA analysis, respectively. The primary outcome was the agreement of results between IBDoc and the Quantum Blue and ELISA analyses, determined by Bland-Altman plot analysis. RESULTS: We received 152 IBDoc results, 138 samples of residual extraction fluid for Quantum Blue analysis, and 170 fresh stool samples for ELISA analysis. Spearman's rank correlation coefficient was 0.94 for results obtained by IBDoc vs Quantum Blue and 0.85 for results obtained by IBDoc vs ELISA. At the low range of calprotectin level (= 100 mu g/g), and 71% of IBDoc-ELISA results were in agreement. At the high range of calprotectin level (>= 500 mu g/g), 81% of IBDoc-Quantum Blue results were within the predefined limits of agreement (+/- 200 mu g/g) and 64% of IBDoc-ELISA results were in agreement. CONCLUSIONS: Measurements of fecal levels of calprotectin made with home-based lateral flow method were in agreement with measurements made by Quantum Blue and ELISA, as long as concentrations wer

Double venipuncture is not required for adequate S-100B determination in melanoma patients

S-100B is used in melanoma follow-up. This serum biomarker is also present in adipocytes; therefore, subcutaneous adipocytes trapped in the needle before performing a venipuncture could contaminate the serum. The aim was to study the influence of adipocyte contamination on blood samples used for S-100B analysis, possibly resulting in falsely elevated S-100B values. A total of 294 serum samples were collected from 147 American Joint Committee on Cancer staging stage III melanoma patients. The mean difference between the first (dummy) and second tubes was 0.003 μg/l (p = 0.077), with a decrease in the second tube. Compared with the second tube, the S-100B level was higher in the first tube in 33.3% of the samples, equal in 36.8% of the samples and lower in 29.9% of the samples. No significant difference between the two consecutively drawn tubes was found. There seems to be no necessity of implementing a dummy tube system for accurate S-100B determination in melanoma patients

Selecting children with suspected inflammatory bowel disease for endoscopy with the calgranulin C or calprotectin stool test:Protocol of the CACATU study

Introduction The introduction of the faecal calprotectin (FC) test to screen children with chronic gastrointestinal complaints has helped the clinician to decide whether or not to subject the patient to endoscopy. In spite of this, a considerable number of patients without inflammatory bowel disease (IBD) is still scoped. Faecal calgranulin C (S100A12) is a marker of intestinal inflammation that is potentially more specific for IBD than FC, as it is exclusively released by activated granulocytes. Objective To determine whether the specificity of S100A12 is superior to the specificity of FC without sacrificing sensitivity in patients with suspected IBD. Methods An international prospective cohort of children with suspected IBD will be screened with the existing FC stool test and the new S100A12 stool test. The reference standard (endoscopy with biopsies) will be applied to patients at high risk of IBD, while a secondary reference (clinical follow-up) will be applied to those at low risk of IBD. The differences in specificity and sensitivity between the two markers will be calculated. Ethics and dissemination This study is submitted to and approved by the Medical Ethics Review Committee of the University Medical Center Groningen (the Netherlands) and the Antwerp University Hospital (Belgium). The results will be disseminated through a peer-reviewed publication, conference presentation and incorporation in the upcoming National Guideline on Diagnosis and Therapy of IBD in Children

Tumor markers in finding recurrent disease in colorectal cancer: a diagnostic review

Aim: In the search for evidence-based follow-up of patients after resection for colorectal cancer, numerous tumor markers have been proposed. This review has evaluated these markers and comments on the diagnostic accuracy in finding recurrent disease in relation to Carcino-Embryonic Antigen (CEA). Methods: A comprehensive literature review (1985-2010) was performed by two independent reviewers. Sensitivity and specificity of markers mentioned in the articles were checked by recalculation. A validated quality score system was used to estimate study quality. Results: Seventeen studies focusing on eight different markers were included. Three markers were shown to have comparable or better accuracy than CEA: TPA, CA 242 and CA 72-4 in at least one study. These three markers, from four independent studies, showed a tumor marker sensitivity of &gt; 60% in combination with an outperformance of CEA in follow-up. These results were not confirmed by six other studies investigating the same markers. Conclusion: This review revealed three tumor markers other than CEA that have been shown to adequately indicate recurrences in colorectal cancer. However, comparability of studies was difficult. Therefore a prospective study of these markers seems necessary to investigate their real value, and to overcome design and inclusion biases

Epidemiology of thyroid disorders in the Lifelines Cohort Study (the Netherlands)

Background Thyroid hormone plays a pivotal role in human metabolism. In epidemiologic studies, adequate registration of thyroid disorders is warranted. We examined the prevalence of thyroid disorders, reported thyroid medication use, thyroid hormone levels, and validity of thyroid data obtained from questionnaires in the Lifelines Cohort Study. Methods We evaluated baseline data of all 152180 subjects (aged 18-93 years) of the Lifelines Cohort Study. At baseline, participants were asked about previous thyroid surgery and current and previous thyroid hormone use. At follow-up (n = 136776, after median 43 months), incident thyroid disorders could be reported in an open, non-structured question. Data on baseline thyroid hormone measurements (TSH, FT4 and FT3) were available in a subset of 39935 participants. Results Of the 152180 participants, mean (+/- SD) age was 44.6 +/- 13.1 years and 58.5% were female. Thyroid medication was used by 4790 participants (3.1%); the majority (98.2%) used levothyroxine, and 88% were females. 59.3% of levothyroxine users had normal TSH levels. The prevalence of abnormal TSH levels in those not using thyroid medication was 10.8%; 9.4% had a mildly elevated (4.01-10.0 mIU/L), 0.7% had suppressed (10.0 mIU/L) TSH levels. Over 98% of subjects with TSH between 4 and 10 mIU/L had normal FT4. Open text questions allowing to report previous thyroid surgery and incident thyroid disorders proved not to be reliable and severely underestimated the true incidence and prevalence of thyroid disorders. Conclusions Undetected thyroid disorders were prevalent in the general population, whereas the prevalence of thyroid medication use was 3.1%. Less than 60% of individuals using levothyroxine had a normal TSH level. The large group of individuals with subclinical hypothyroidism (9.4%) offers an excellent possibility to prospectively follow the natural course of this disorder. Both structured questions as well as linking to G.P.'s and pharmacists' data are necessary to improve the completeness and reliability of Lifelines' data on thyroid disorders

Reference values of fecal calgranulin C (S100A12) in school aged children and adolescents

Background: Calgranulin C (S100A12) is an emerging marker of inflammation. It is exclusively released by activated neutrophils which makes this marker potentially more specific for inflammatory bowel disease (IBD) compared to established stool markers including calprotectin and lactoferrin. We aimed to establish a reference value for S100A12 in healthy children and investigated whether S100A12 levels can discriminate children with IBD from healthy controls. Methods: In a prospective community-based reference interval study we collected 122 stool samples from healthy children aged 5-19 years. Additionally, feces samples of 41 children with suspected IBD (who were later confirmed by endoscopy to have IBD) were collected. Levels of S100A12 were measured with a sandwich enzyme-linked immunosorbent assay (ELISA) (Inflamark (R)). The limit of detection was 0.22 mu g/g. Results: The upper reference limit in healthy children was 0.75 mu g/g (90% confidence interval: 0.30-1.40). Median S100A12 levels were significantly higher in patients with IBD (8.00 mu g/g [interquartile range (IQR) 2.5-11.6] compared to healthy controls [0.22 mu g/g (IQR <0.22); p <0.001]). The best cutoff point based on receiver operating characteristic curve was 0.33 mu g/g (sensitivity 93%; specificity 97%). Conclusions: Children and teenagers with newly diagnosed IBD have significantly higher S100A12 results compared to healthy individuals. We demonstrate that fecal S100A12 shows diagnostic promise under ideal testing conditions. Future studies need to address whether S100A12 can discriminate children with IBD from nonorganic disease in a prospective cohort with chronic gastrointestinal complaints, and how S100A12 performs in comparison with established stool markers

Leptin levels in SARS-CoV-2 infection related respiratory failure:A cross-sectional study and a pathophysiological framework on the role of fat tissue

Obesity is a risk factor for SARS-CoV-2 infected patients to develop respiratory failure. Leptin produced in visceral fat might play a role in the deterioration to mechanical ventilation. A cross sectional study was performed. The mean BMI was 31 kg/m2 (range 24.8-48.4) for the 31 SARS-CoV-2 ventilated patients and 26 kg/m2 (range 22.4-33.5) for 8 critically ill non-infected control patients. SARS-CoV-2 infected patients with a similar BMI as control patients appear to have significantly higher levels of serum leptin. The mean leptin level was 21.2 (6.0-85.2) vs 5.6 (2.4-8.2) ug/L for SARS-CoV-2 and controls respectively (p = 0.0007). With these findings we describe a clinical and biological framework that may explain these clinical observations. The ACE2 utilization by the virus leads to local pulmonary inflammation due to ACE2-ATII disbalance. This might be enhanced by an increase in leptin production induced by SARS-CoV-2 infection of visceral fat. Leptin receptors in the lungs are now more activated to enhance local pulmonary inflammation. This adds to the pre-existent chronic inflammation in obese patients. Visceral fat, lung tissue and leptin production play an interconnecting role. This insight can lead the way to further research and treatment