Utility of Cystatin C-based Equation for the Estimation of Glomerular Filtration Rate in a Pediatric Population

BACKGROUND

The accurate assessment of kidney function is vital for the early detection of kidney damage. The estimated glomerular filtration rate GFR (eGFR) from serum cystatin C (CysC) and creatinine-based equations are commonly used in clinical practice as an alternative to the invasive measured glomerular filtration rate (mGFR), which is the usually accepted overall best index of kidney function in health and disease. Recently the CKiD under 25 (CkiD U25) equations have been shown to perform well in children and young adults with chronic kidney disease (CKD). In this focused report, we evaluated the performance of the CkiD U25 equations alongside 3 non-race-corrected (NRC) eGFR equations commonly used in pediatrics in our cohort.

METHODS

mGFR measured following the intravenous injection of tracer Tc-99mDTPA was retrospectively compared with eGFR from these equations in 57 patients (6 months to 22 years) from different races/ethnicities. Ordinary least squares regression analyses were used to assess correlation between the mGFRs and eGFRs.

RESULTS

The average mGFR for this cohort was 84.1 mL/min/1.73 m2. The NRC creatinine equations overestimated eGFR across all groups, with the lowest bias for CKiD U25-creatinine (22.59 mL/min/1.73 m2). The best correlations to mGFR, P30, and lowest biases were the CKiD U25-CysC (0.6281, 80.7%, 3.72 mL/min/1.73 m2) and Schwartz CysC (0.6372, 77.2%, -4.68 mL/min/1.73 m2).

CONCLUSIONS

Overall, both CKiD U25-CysC and Schwartz CysC provide a good estimation of mGFR with the CKiD U25-CysC having the overall best performance compared to mGFR in our study.

Path Towards Biopsy-Free Diagnosis of Celiac Disease in Pediatric Patients

BACKGROUND

Laboratory testing for celiac disease in pediatric patients integrates serology, genetic susceptibility and duodenal biopsy examination. The 2023 American College of Gastroenterology guidelines recommend a biopsy-free approach in pediatric patients utilizing tissue transglutaminase antibody titers >10 times upper limit of normal and subsequent endomysial antibody seropositivity as sufficient for diagnosis. The objective of this study is to assess the diagnostic accuracy of biopsy-free approach at our pediatric hospital.

METHODS

We conducted a retrospective study involving pediatric patients who underwent biopsy for diagnostic confirmation of celiac disease between May 2019 and May 2023. For these patients, the tissue transglutaminase and endomysial antibody test results were retrieved and performance of biopsy-free approach was assessed using the duodenal histology as the gold standard for celiac disease diagnosis.

RESULTS

Tissue transglutaminase antibody titers >10 times upper limit of normal alone demonstrated a positive predictive value of 99% for identifying celiac disease in children. Although endomysial antibody testing is underutilized at our center, its inclusion further improved the predictability to 100 %.

CONCLUSION

Positive predictive value of tissue transglutaminase antibody titers >10 times upper limit of normal is sufficiently high for celiac disease diagnosis in children and may allow for deferral of duodenal biopsy at diagnosis.

Effectiveness of Cord blood as a Strategy to rule out Conjugated Hyperbilirubinemia

Early detection of biliary atresia is crucial for timely intervention and improved outcomes in infants with elevated conjugated bilirubin levels. This study aims to investigate the viability of cord blood gas analysis as a novel method for assessing conjugated bilirubin levels. Infants with high heel stick levels also showed elevated cord blood bilirubin levels, indicating that cord blood testing could replace the need for repeat heel stick tests, especially benefiting low birth weight infants. Ongoing research, including larger cohorts and alternative bilirubin measurement methods, will further validate this innovative screening approach. Infants with biliary atresia have high conjugated bilirubin levels at birth. As a result, infants can be screened with newborn conjugated bilirubin measurements, to allow for early detection, timely treatment, and the best chances of delaying or even avoiding the need for a liver transplant [1]. An important limitation of screening, however, is that infants must undergo a separate blood test. To overcome this limitation, we investigated whether conjugated bilirubin measurements from cord blood could be useful.

CADHERIN-11 regulation of myeloid phagocytes and autoimmune inflammation in murine lupus

BACKGROUND AND OBJECTIVE

Understanding the regulation of efferocytosis by myeloid phagocytes is important in identifying novel targets in systemic lupus erythematosus (SLE). Cadherin-11 (CDH11), a cell adhesion molecule, is implicated in inflammatory arthritis and fibrosis and recently been shown to regulate macrophage phagocytosis. The extent and mechanism of this regulation is unknown. Our objective was to examine the extent to which CDH11 regulates myeloid phagocytes and contributes to autoimmunity and tissue inflammation.

METHODS

We analyzed efferocytosis in macrophages and dendritic cells (DCs) from WT and Cdh11-/- mice and investigated the mechanisms in vitro. We investigated the role of CDH11 in disease development in vivo using the pristane induced lupus model. To translate the clinical relevance of CDH11 in human disease, we measured serum CDH11 levels in two independent pediatric SLE (pSLE) cohorts and healthy controls.

RESULTS

Using bone marrow derived macrophages (BMDMs) and DCs (BMDCs), we found impaired efferocytosis in phagocytes from Cdh11-/- mice, mediated by downregulated efferocytosis receptor expression and RhoGTPase activation. Specifically, loss of CDH11 downregulated Mertk expression and Rac1 activation in BMDMs, and integrin αVβ3 expression and Cdc42 activation in BMDCs, highlighting distinct pathways. In vivo, Cdh11-/- mice displayed defective efferocytosis and increased accumulation of apoptotic debris in pristane-induced lupus. Further, Cdh11-/- mice had enhanced systemic inflammation and autoimmune inflammation with increased anti-dsDNA autoantibodies, splenomegaly, type I interferons, and inflammatory cytokines. Paradoxically, at the tissue level, Cdh11-/- mice were protected against glomerulonephritis, indicating a dual role in murine lupus. Finally, SLE patients had increased serum CDH11 compared to controls.

CONCLUSION

This study highlights a novel role of CDH11 in regulating myeloid cells and efferocytosis and its potential as a contributor to development in autoimmunity murine lupus. Despite the increase in autoimmunity, Cdh11-/- mice developed decreased tissue inflammation and damage.

Dawn-to-dusk dry fasting decreases circulating inflammatory cytokines in subjects with increased body mass index

Background

The circadian rhythm involves numerous metabolic processes, including sleep/awakening, body temperature regulation, hormone secretion, hepatic function, cellular plasticity, and cytokine release (inflammation), that appear to have a dynamic relationship with all the processes above. Studies have linked various cytokines to the chronic state of low-grade inflammation and oxidative stress in obesity. Dawn-to-dusk dry fasting (DDDF) could alleviate the adverse effects of obesity by decreasing inflammation. This study examined the effects of DDDF on circulating inflammatory cytokines in subjects with increased body mass index (BMI).

Methods

The current observational prospective study included adult subjects with a BMI equal to or greater than 25 kg/m2 who practiced the annual religious 30-day DDDF. Individuals with significant underlying medical conditions were excluded to limit confounding factors. All subjects were evaluated within two weeks before 30-day DDDF, within the fourth week of 30-day DDDF, and within two weeks after 30-day DDDF. Multiple cytokines and clinical health indicators were measured at each evaluation.

Results

Thirteen subjects (10 men and three women) with a mean age of 32.9 years (SD = 9.7 years) and a mean BMI of 32 kg/m2 (SD = 4.6 kg/m2) were included. An overall associated decrease in the levels of multiple cytokines with DDDF was observed. A significant decrease in the mean interleukin 1 beta level was observed within the fourth week of 30-day DDDF (P = 0.045), which persisted even after the fasting period (P = 0.024). There was also a significant decrease in the mean levels of interleukin 15 (IL-15) (P = 0.014), interleukin 1 receptor antagonist (P = 0.041), macrophage-derived chemokine (MDC) (P = 0.013), and monokine induced by interferon gamma/chemokine (C-X-C motif) ligand 9 (P = 0.027) within the fourth week of 30-day DDDF and in the mean levels of fibroblast growth factor 2 (P = 0.010), interleukin 12 p40 subunit (P = 0.038), interleukin 22 (P = 0.025) and tumor necrosis factor alpha (P = 0.046) within two weeks after 30-DDDF. In terms of anthropometric parameters, there was a decrease in mean body weight (P = 0.032), BMI (P = 0.028), and hip circumference (P = 0.007) within the fourth week of 30-day DDDF and a decrease in mean weight (P = 0.026), BMI (P = 0.033) and hip circumference (P = 0.016) within two weeks after 30-day DDDF compared with the levels measured within two weeks before 30-day DDDF. Although there was no significant correlation between changes in weight and changes in circulating inflammatory cytokines, there was a significant positive correlation between changes in waist circumference and changes in specific inflammatory cytokines (e.g., IL-15, MDC, platelet-derived growth factor, soluble CD40L, vascular endothelial growth factor A) within the fourth week of 30-day DDDF and/or two weeks after 30-day DDDF. A significant decrease in mean average resting heart rate within the fourth week of 30-day DDDF was also observed (P = 0.023), and changes between average resting heart rate and changes in interleukin-8 levels within the fourth week of 30-day DDDF compared with baseline levels were positively correlated (r = 0.57, P = 0.042).

Conclusion

DDDF appears to be a unique and potent treatment to reduce low-grade chronic inflammation caused by obesity and visceral adiposity. Further studies with more extended follow-up periods are warranted to investigate the long-term anti-inflammatory benefits of DDDF in individuals with increased BMI.

Validation of a whole blood machine learning strategy for distinguishing between bacterial and viral infection in a pediatric hospital setting

Similar symptoms between viral and bacterial diseases often make diagnosis difficult. This study assessed the clinical performance of the newly cleared whole-blood Bacterial versus Viral Score assay in our pediatric cohort to the previously validated serum assay and emergency department physician diagnosis. This assay shows excellent agreement (R = 0.997) with the serum assay and has great diagnostic accuracy when compared to physician diagnosis.

Cystic fibrosis-related diabetes screening at a large pediatric center

OBJECTIVE

Cystic Fibrosis Foundation guidelines recommend annual diabetes screening by oral glucose tolerance test (OGTT) in pediatric patients with cystic fibrosis (CF) starting at the age of 10 years. Adherence to these guidelines proves to be challenging, and the nationwide screening rates are still considered suboptimal. The aim of this study was to assess and improve the screening rates at our large pediatric center.

METHODS

A 4-year retrospective audit of OGTT completion among pediatric patients with CF of age ≥10 years who are not yet diagnosed with diabetes was conducted. A collaborative working group was formed to identify the barriers to screening and formulate a quality improvement plan, which was monitored and evaluated for a 9-month period.

RESULTS

Diabetes screening rates determined by OGTT completion at our center showed a gradual decline during the COVID-19 pandemic from 2019 to 2022. Following the implementation of the quality improvement plan during the summer of 2023, there was a marked increase in OGTT ordering compliance by providers as well as test completion by patients. Notably, the fractional OGTT completion rate rose from 45% during the preintervention phase (January-April 2023) to 70% during the postintervention phase (May-September 2023).

CONCLUSION

Diabetes screening in pediatric patients with CF can be effectively improved by refining practices related to patient experience, care coordination, and laboratory testing strategies.

Reticulocyte hemoglobin equivalent as a marker to assess iron deficiency: A large pediatric tertiary care hospital study

INTRODUCTION

Detection of iron deficiency (ID) remains challenging. We aimed to evaluate the performance of reticulocyte hemoglobin equivalent (Ret-He) as a potential diagnostic marker to assess ID and iron deficiency anemia (IDA) in a large pediatric cohort.

METHODS

A total of 3158 patients (aged 15 days to 19 years with a median age of 8.5 years; 60.2% female) were retrospectively studied. Statistical analysis was performed (a) to evaluate relationship of Ret-He with other relevant complete blood count and iron panel parameters; (b) to compare the levels of Ret-He in ID and IDA groups to a control group; and (c) to assess sensitivity and specificity of Ret-He in ID, IDA, and anemia without ID groups.

RESULTS

Ret-He values were significantly positively correlated to ferritin and transferrin saturation (TSAT). The median Ret-He was significantly lower in ID. A Ret-He cutoff of ≤30.0 pg distinguished cases of ID from the control group with a sensitivity of 90.2%, specificity of 59.5%, and area under curve (AUC) of 0.88. Ret-He showed better diagnostic performance in the IDA group and acceptable performance for ID without anemia. The sensitivity, specificity, and AUC were 90.1%, 80.9%, and 0.93 for IDA at cutoff value of ≤27.4 pg, and 80.8%, 51.1%, and 0.70 for ID without anemia at cutoff value of ≤30.8 pg, respectively.

CONCLUSION

Our large pediatric tertiary care hospital study demonstrates that Ret-He is a reliable marker to help confirm IDA in pediatric population. However, further studies are needed for its use to capture the early stages of ID.

Liquid Chromatography-Tandem Mass Spectrometry-Based Therapeutic Monitoring of Plasma Atovaquone Concentrations in Pediatric Patients

Atovaquone is an FDA-approved antiparasitic and antifungal therapeutic that is currently used as a prophylactic agent to prevent Pneumocystis carinii pneumonia (PCP) infections in acute myeloid leukemia (AML) patients after receiving hematopoietic stem cell transplantation (HSCT). Recent studies have shown that atovaquone has shown potential as an anticancer agent. The high variability in atovaquone bioavailability prompts the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients. Briefly, an organic-based solvent system is used to precipitate protein and extract the atovaquone content from each patient-derived plasma sample. After completing a second stage of sample dilution (5000-fold overall), a 2 μL volume of the plasma extract is analyzed using the liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based bioanalytical method described.

ChatGPT-Exploring Its Role in Clinical Chemistry

OBJECTIVE

To evaluate the utility of artificial intelligence-powered language models (ChatGPT 3.5 and GPT-4) compared to trainees and clinical chemists in responding to common laboratory questions in the broad area of Clinical Chemistry.

METHODS

35 questions from real-life case scenarios, clinical consultations, and clinical chemistry testing questions were used to evaluate ChatGPT 3.5, and GPT-4 alongside clinical chemistry trainees (residents/fellows) and clinical chemistry faculty. The responses were scored based on category and based on years of experience.

RESULTS

The Senior Chemistry Faculty demonstrated superior accuracy with 100% of correct responses compared to 90.5%, 82.9%, and 71.4% of correct responses from the junior chemistry faculty, fellows, and residents respectively. They all outperformed both ChatGPT 3.5 and GPT-4 which generated 60% and 71.4% correct responses respectively. Of the sub-categories examined, ChatGPT 3.5 achieved 100% accuracy in endocrinology while GPT-4 did not achieve 100% accuracy in any subcategory. GPT-4 was overall better than ChatGPT 3.5 by generating similar correct responses as residents (71.4%) but performed poorly to human participants when both partially correct and incorrect indices were considered.

CONCLUSION

Despite all the advances in AI-powered language models, ChatGPT 3.5 and GPT-4 cannot replace a trained pathologist in answering clinical chemistry questions. Caution should be observed by people, especially those not trained in clinical chemistry, to interpret test results using chatbots.

Best Practices for Effective Management of Point of Care Testing

With the recent COVID-19 pandemic, point-of-care testing has gained tremendous attention, particularly in acute care settings. The point-of-care testing landscape is rapidly expanding and being contemplated for any crucial test with a central laboratory turnaround time >25% of the clinical decision time. A typical point-of-care testing program within a large hospital system encompasses a multitude of operators utilizing a wide range of devices across multiple testing sites. Thus, managing a large point-of-care testing network remains a daunting task with challenges related to staffing, standardization, quality management, training and competency assessment, and data management. This review will focus on understanding the general organization as well as the roles and responsibilities of various point-of-care testing stakeholders in addressing these challenges. More importantly, it will discuss the strategies and best practices for effective point-of-care testing management based on consensus recommendations from professional societies as well as our experience at Texas Childrens Hospital.

Stratification of Pediatric COVID-19 Cases Using Inflammatory Biomarker Profiling and Machine Learning

While pediatric COVID-19 is rarely severe, a small fraction of children infected with SARS-CoV-2 go on to develop multisystem inflammatory syndrome (MIS-C), with substantial morbidity. An objective method with high specificity and high sensitivity to identify current or imminent MIS-C in children infected with SARS-CoV-2 is highly desirable. The aim was to learn about an interpretable novel cytokine/chemokine assay panel providing such an objective classification. This retrospective study was conducted on four groups of pediatric patients seen at multiple sites of Texas Children's Hospital, Houston, TX who consented to provide blood samples to our COVID-19 Biorepository. Standard laboratory markers of inflammation and a novel cytokine/chemokine array were measured in blood samples of all patients. Group 1 consisted of 72 COVID-19, 70 MIS-C and 63 uninfected control patients seen between May 2020 and January 2021 and predominantly infected with pre-alpha variants. Group 2 consisted of 29 COVID-19 and 43 MIS-C patients seen between January and May 2021 infected predominantly with the alpha variant. Group 3 consisted of 30 COVID-19 and 32 MIS-C patients seen between August and October 2021 infected with alpha and/or delta variants. Group 4 consisted of 20 COVID-19 and 46 MIS-C patients seen between October 2021 andJanuary 2022 infected with delta and/or omicron variants. Group 1 was used to train an L1-regularized logistic regression model which was tested using five-fold cross validation, and then separately validated against the remaining naïve groups. The area under receiver operating curve (AUROC) and F1-score were used to quantify the performance of the cytokine/chemokine assay-based classifier. Standard laboratory markers predict MIS-C with a five-fold cross-validated AUROC of 0.86 ± 0.05 and an F1 score of 0.78 ± 0.07, while the cytokine/chemokine panel predicted MIS-C with a five-fold cross-validated AUROC of 0.95 ± 0.02 and an F1 score of 0.91 ± 0.04, with only sixteen of the forty-five cytokines/chemokines sufficient to achieve this performance. Tested on Group 2 the cytokine/chemokine panel yielded AUROC = 0.98 and F1 = 0.93, on Group 3 it yielded AUROC = 0.89 and F1 = 0.89, and on Group 4 AUROC = 0.99 and F1 = 0.97. Adding standard laboratory markers to the cytokine/chemokine panel did not improve performance. A top-10 subset of these 16 cytokines achieves equivalent performance on the validation data sets. Our findings demonstrate that a sixteen-cytokine/chemokine panel as well as the top ten subset provides a highly sensitive, and specific method to identify MIS-C in patients infected with SARS-CoV-2 of all the major variants identified to date.

Comparison of random urine protein/creatinine ratio with 24-hour urine protein in suspected pre-eclampsia

Introduction

Proteinuria is one of the classical criteria for the diagnosis of pre-eclampsia. The gold standard remains the measurement of 24-h urine protein which is time consuming and prone to preanalytical errors. Random urine protein creatinine ratio (UPCR) is endorsed by clinical practice guidelines as a faster alternative. The aim of this study was to evaluate the correlation between the 24-h urine protein excretion and UPCR in the identification of proteinuria in suspected preeclamptic patients.

Method

A total of 51 women with suspected pre-eclampsia from the maternal fetal clinic of our institution were retrospectively studied. The correlation between the UPCR in random urine samples and protein excretion in the 24-h urine collection was determined by Deming Regression analysis and Pearson correlation on EP evaluator and SPSS respectively.

Result

There was a significant positive correlation between the numerical values obtained by 24-h urine protein and the UPCR (R = 0.88, P < 0.001). Concordance analysis showed 81.1% positive agreement for proteinuria between methods (>300 mg/24hr and >0.3) and 71.4% negative agreement. The clinical sensitivity and specificity of the UPCR was 74% and 69% respectively.

Conclusion

Overall, UPCR was well correlated with 24-h urine protein and could be an effective and compliant screening tool to indicate proteinuria in preeclamptic patients.

Unique Hemoglobinopathy Pattern Following Treatment with Voxelotor

OBJECTIVE

Voxelotor, a FDA-approved drug for the treatment of patients with sickle cell disease (SCD), inhibits hemoglobin S (HbS) polymerization and increases total hemoglobin via hemolysis reduction. This drug has shown unique patterns in hemoglobin fractionation, affecting its interpretation. We aimed to evaluate whether these voxelotor-induced changes can be linked to improvement of hemolysis markers in pediatric patients on voxelotor.

METHODS

A total of 15 patients (age 12 to 20 years; 40% females) on voxelotor were evaluated to compare changes in the hemoglobin fractionation by capillary electrophoresis, total hemoglobin, reticulocyte percentage (retic%), lactate dehydrogenase (LDH), and bilirubin measurements before and after the recorded date of voxelotor prescription.

RESULTS

Hemoglobin fractionation showed changes in the profile of 60% (9/15) of the patients studied. Out of the 9 patients for which voxelotor showed changes in the hemoglobin fractionation, 44% (4/9) had an increase of >1 g/dL in their total hemoglobin after voxelotor treatment was started. Assessment of other hemolysis markers available showed decreased LDH (4/4), retic % (6/8), and bilirubin (3/4).

CONCLUSIONS

Unique pattern of hemoglobin fractionation analysis following therapy with voxelotor has potential as a tool for the assessment of response and/or compliance to voxelotor for the treatment of SCD.

Pediatric vitamin D: Pseudo-hypervitaminosis

BACKGROUND

Vitamin D toxicity is rare in pediatric population. Falsely elevated levels of 25-hydroxyvitamin D have been reported as a major challenge with immunoassay methods for quantifying vitamin D metabolites.

CASE PRESENTATION AND METHOD

Here, we present two pediatric cases of falsely elevated 25-hydroxyvitamin D that resulted in unnecessary further testing. We also report significant same-day variation in the measurement of 25-hydroxyvitamin D using the Abbott i2000SR immunoassay. Samples were spun twice and their values were confirmed with the gold standard liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for confirmation.

CONCLUSION

The addition of a centrifugation step prior to sample testing resolved the variation observed in the measurement of 25-hydroxyvitamin D levels. The patient samples were confirmed with instruments from a different vendor and LC-MS/MS. Re-centrifugation of samples resolved the variation in the 25-hydroxyvitamin D values.

Increased Adipocyte Hypertrophy in Patients with Nascent Metabolic Syndrome

Background and Aims: Metabolic Syndrome (MetS), a global problem, predisposes to an increased risk for type 2 diabetes and premature cardiovascular disease. While MetS is associated with central obesity, there is scanty data on adipocyte hypertrophy, increased fat cell size (FCS), in MetS. The aim of this study was to investigate FCS status in adipose tissue (AT) biopsy of patients with nascent MetS without the confounding of diabetes, cardiovascular disease, smoking, or lipid therapy. Methods and Results: Fasting blood and subcutaneous gluteal AT biopsies were obtained in MetS (n = 20) and controls (n = 19). Cardio-metabolic features, FFA levels, hsCRP, and HOMA-IR were significantly increased in patients with MetS. Waist-circumference (WC) adjusted-FCS was significantly increased in patients with MetS and increased with increasing severity of MetS. Furthermore, there were significant correlations between FCS with glucose, HDL-C, and the ratio of TG: HDL-C. There were significant correlations between FCS and FFA, as well as endotoxin and monocyte TLR4 abundance. Additionally, FCS correlated with readouts of NLRP3 Inflammasome activity. Most importantly, FCS correlated with markers of fibrosis and angiogenesis. Conclusions: In conclusion, in patients with nascent MetS, we demonstrate WC-adjusted increase in FCS from gluteal adipose tissue which correlated with cellular inflammation, fibrosis, and angiogenesis. While these preliminary observations were in gluteal fat, future studies are warranted to confirm these findings in visceral and other fat depots.

Validation of a Multi-Analyte Immunoassay for Distinguishing Bacterial vs. Viral Infections in a Pediatric Cohort

BACKGROUND

Clinical presentation of viral and bacterial infections or co-infections overlaps significantly. Pathogen identification is the gold standard for appropriate treatment. Recently, FDA cleared a multivariate index test called MeMed-BV that distinguishes viral and bacterial infections based on the differential expression of 3 host proteins. Here, we sought to validate MeMed-BV immunoassay on MedKey analyzer in our pediatric hospital following guidelines from the Clinical and Laboratory Standards Institute.

METHODS

The analytical performance of the MeMed-BV test was evaluated with precision (intra- and inter-assay), method comparison and interference studies. The clinical performance (diagnostic sensitivity and specificity) of the MeMed-BV test was assessed by conducting a retrospective cohort study (n=60) using plasma samples from pediatric patients with acute febrile illness who visited the emergency department of our hospital.

RESULTS

MeMed-BV showed acceptable intra- and inter-assay precision with a range of <3 score units in both the high-score bacterial as well as the low-score viral controls. Diagnostic accuracy studies revealed a sensitivity of 94% and specificity of 88% for identifying bacterial infections or co-infections. Our MeMed-BV results showed an excellent agreement (R=0.998) with manufacturer's laboratory data and compared well with ELISA studies. Gross hemolysis and icterus did not affect the assay, but gross lipemia showed a considerable bias in samples with moderate likelihood of viral infection. Importantly, the MeMed-BV test performed better than routinely measured infection-related biomarkers like white blood cell counts, procalcitonin and C-reactive protein in classifying bacterial infections.

CONCLUSION

MeMed-BV immunoassay demonstrated acceptable analytical performance and is reliable for distinguishing viral and bacterial infections or co-infections in pediatric patients. Future studies are warranted to examine the clinical utility, especially with respect to reducing the need for blood cultures and time to treatment for the patient.

SARS-CoV-2 Antibody Titers and Severity of Multisystem Inflammatory Syndrome in Children

OBJECTIVE

Multisystem inflammatory syndrome in children (MIS-C) is a rare yet serious pathological consequence of SARS-CoV-2 infection which is reported 4-12 weeks after the onset of COVID-19 in children and adolescents. The most common hyper-inflammatory conditions mimicking the clinical presentation of MIS-C include Kawasaki disease and toxic shock syndrome. The surveillance criteria of MIS-C were recently revised by US Center for Disease Control and Prevention to improve diagnostic precision. Although previous studies have shown that SARS-CoV-2 antibody titers correlate with COVID-19 severity, their relation to MIS-C severity remains poorly understood and the aim of the study was to investigate this.

METHODS

As all the MIS-C patients get a SARS-CoV-2 antibody test performed on the first day of hospitalization, here we attempted to stratify risk for adverse outcomes due to MIS-C based on the SARS-CoV-2 antibody titers.

RESULTS

Our studies demonstrated that SARS-CoV-2 antibody titers, specifically Total (IgG/IgM/partial IgA), Nucleocapsid IgG, and Spike IgM, do not correlate with MIS-C severity assessed based on the ICU admission, inotropic support, and mechanical respiratory support requirements.

CONCLUSION

Therefore, it might not be appropriate to predict the clinical course of patients presenting with MISC based on quantitative serology testing.

Stratification of Pediatric COVID-19 cases by inflammatory biomarker profiling and machine learning

An objective method to identify imminent or current Multi-Inflammatory Syndrome in Children (MIS-C) infected with SARS-CoV-2 is highly desirable. The aims was to define an algorithmically interpreted novel cytokine/chemokine assay panel providing such an objective classification. This study was conducted on 4 groups of patients seen at multiple sites of Texas Children's Hospital, Houston, TX who consented to provide blood samples to our COVID-19 Biorepository. Standard laboratory markers of inflammation and a novel cytokine/chemokine array were measured in blood samples of all patients. Group 1 consisted of 72 COVID-19, 66 MIS-C and 63 uninfected control patients seen between May 2020 and January 2021 and predominantly infected with pre-alpha variants. Group 2 consisted of 29 COVID-19 and 43 MIS-C patients seen between January-May 2021 infected predominantly with the alpha variant. Group 3 consisted of 30 COVID-19 and 32 MIS-C patients seen between August-October 2021 infected with alpha and/or delta variants. Group 4 consisted of 20 COVID-19 and 46 MIS-C patients seen between October 2021-January 2022 infected with delta and/or omicron variants. Group 1 was used to train a L1-regularized logistic regression model which was validated using 5-fold cross validation, and then separately validated against the remaining naïve groups. The area under receiver operating curve (AUROC) and F1-score were used to quantify the performance of the algorithmically interpreted cytokine/chemokine assay panel. Standard laboratory markers predict MIS-C with a 5-fold cross-validated AUROC of 0.86 ± 0.05 and an F1 score of 0.78 ± 0.07, while the cytokine/chemokine panel predicted MIS-C with a 5-fold cross-validated AUROC of 0.95 ± 0.02 and an F1 score of 0.91 ± 0.04, with only sixteen of the forty-five cytokines/chemokines sufficient to achieve this performance. Tested on Group 2 the cytokine/chemokine panel yielded AUROC =0.98, F1=0.93, on Group 3 it yielded AUROC=0.89, F1 = 0.89, and on Group 4 AUROC= 0.99, F1= 0.97). Adding standard laboratory markers to the cytokine/chemokine panel did not improve performance. A top-10 subset of these 16 cytokines achieves equivalent performance on the validation data sets. Our findings demonstrate that a sixteen-cytokine/chemokine panel as well as the top ten subset provides a sensitive, specific method to identify MIS-C in patients infected with SARS-CoV-2 of all the major variants identified to date.

Iron deficiency and internalizing symptom severity in unmedicated adolescents: a pilot study

BACKGROUND

Iron plays a key role in a broad set of metabolic processes. Iron deficiency is the most common nutritional deficiency in the world, but its neuropsychiatric implications in adolescents have not been examined.

METHODS

Twelve- to 17-year-old unmedicated females with major depressive or anxiety disorders or with no psychopathology underwent a comprehensive psychiatric assessment for this pilot study. A T1-weighted magnetic resonance imaging scan was obtained, segmented using Freesurfer. Serum ferritin concentration (sF) was measured. Correlational analyses examined the association between body iron stores, psychiatric symptom severity, and basal ganglia volumes, accounting for confounding variables.

RESULTS

Forty females were enrolled, 73% having a major depressive and/or anxiety disorder, 35% with sF < 15 ng/mL, and 50% with sF < 20 ng/mL. Serum ferritin was inversely correlated with both anxiety and depressive symptom severity (r = -0.34, p < 0.04 and r = -0.30, p < 0.06, respectively). Participants with sF < 15 ng/mL exhibited more severe depressive and anxiety symptoms as did those with sF < 20 ng/mL. Moreover, after adjusting for age and total intracranial volume, sF was inversely associated with left caudate (Spearman's r = -0.46, p < 0.04), left putamen (r = -0.58, p < 0.005), and right putamen (r = -0.53, p < 0.01) volume.

CONCLUSIONS

Brain iron may become depleted at a sF concentration higher than the established threshold to diagnose iron deficiency (i.e. 15 ng/mL), potentially disrupting brain maturation and contributing to the emergence of internalizing disorders in adolescents.

Gut bacteria influence Blastocystis sp. phenotypes and may trigger pathogenicity

Whilst the influence of intestinal microbiota has been shown in many diseases such as irritable bowel syndrome, colorectal cancer, and aging, investigations are still scarce on its role in altering the nature of other infective organisms. Here we studied the association and interaction of Blastocystis sp. and human intestinal microbiota. In this study, we investigated the gut microbiome of Blastocystis sp.-free and Blastocystis sp. ST3-infected individuals who are symptomatic and asymptomatic. We tested if the expression of phenotype and pathogenic characteristics of Blastocystis sp. ST3 was influenced by the alteration of its accompanying microbiota. Blastocystis sp. ST3 infection alters bacterial composition. Its presence in asymptomatic individuals showed a significant effect on microbial richness compared to symptomatic ones. Inferred metagenomic findings suggest that colonization of Blastocystis sp. ST3 could contribute to the alteration of microbial functions. For the first time, we demonstrate the influence of bacteria on Blastocystis sp. pathogenicity. When Blastocystis sp. isolated from a symptomatic individual was co-cultured with bacterial suspension of Blastocystis sp. from an asymptomatic individual, the parasite demonstrated increased growth and reduced potential pathogenic expressions. This study also reveals that Blastocystis sp. infection could influence microbial functions without much effect on the microbiota diversity itself. Our results also demonstrate evidence on the influential role of gut microbiota in altering the characteristics of the parasite, which becomes the basis for the contradictory findings on the parasite's pathogenic role seen across different studies. Our study provides evidence that asymptomatic Blastocystis sp. in a human gut can be triggered to show pathogenic characteristics when influenced by the intestinal microbiota.

Serum biomarkers correlated with liver stiffness assessed in a multicenter study of pediatric cholestatic liver disease

BACKGROUND AND AIMS

Detailed investigation of the biological pathways leading to hepatic fibrosis and identification of liver fibrosis biomarkers may facilitate early interventions for pediatric cholestasis.

APPROACH AND RESULTS

A targeted enzyme-linked immunosorbent assay-based panel of nine biomarkers (lysyl oxidase, tissue inhibitor matrix metalloproteinase (MMP) 1, connective tissue growth factor [CTGF], IL-8, endoglin, periostin, Mac-2-binding protein, MMP-3, and MMP-7) was examined in children with biliary atresia (BA; n = 187), alpha-1 antitrypsin deficiency (A1AT; n = 78), and Alagille syndrome (ALGS; n = 65) and correlated with liver stiffness (LSM) and biochemical measures of liver disease. Median age and LSM were 9 years and 9.5 kPa. After adjusting for covariates, there were positive correlations among LSM and endoglin ( p = 0.04) and IL-8 ( p < 0.001) and MMP-7 ( p < 0.001) in participants with BA. The best prediction model for LSM in BA using clinical and lab measurements had an R2 = 0.437; adding IL-8 and MMP-7 improved R2 to 0.523 and 0.526 (both p < 0.0001). In participants with A1AT, CTGF and LSM were negatively correlated ( p = 0.004); adding CTGF to an LSM prediction model improved R2 from 0.524 to 0.577 ( p = 0.0033). Biomarkers did not correlate with LSM in ALGS. A significant number of biomarker/lab correlations were found in participants with BA but not those with A1AT or ALGS.

CONCLUSIONS

Endoglin, IL-8, and MMP-7 significantly correlate with increased LSM in children with BA, whereas CTGF inversely correlates with LSM in participants with A1AT; these biomarkers appear to enhance prediction of LSM beyond clinical tests. Future disease-specific investigations of change in these biomarkers over time and as predictors of clinical outcomes will be important.

Growth and differentiation factor 15 (GDF15) levels predict adverse respiratory outcomes in premature neonates

Growth and differentiation factor 15 (GDF15) is a stress-responsive cytokine, and its expression increases during inflammation, hyperoxia, and senescence. Significantly, GDF15 is secreted by the placenta, and maternal levels increase throughout pregnancy. Serum GDF15 level is a promising biomarker for many lung diseases like pulmonary hypertension and pulmonary fibrosis. However, circulating GDF15 levels in preterm infants and their role as a predictor of respiratory outcomes have not been studied. We hypothesized that GDF15 levels would increase with gestational age at birth, and that postnatal GDF15 will be correlated with adverse respiratory outcomes in preterm infants. Scavenged blood samples were retrieved from 57 preterm infants at five time points, from birth until 36-weeks postmenstrual age (PMA). GDF15 levels were measured using ELISA in 114 samples. We performed two-sample t-test, correlation and linear regression, logistic regression, and mixed-effects linear models for statistical analysis, and significance was identified when p < 0.05. Contrary to our hypothesis, for every 1-week increase in gestational age at birth, the predicted GDF15 level decreased by 475.0 pg/ml (p < 0.001). Greater PMA was significantly associated with lower serum GDF15 levels (p < 0.001). Interestingly, higher GDF15 levels were associated with a longer need for mechanical ventilation (p = 0.034), prolonged respiratory support need (p < 0.001), and length of hospital stay (p = 0.006). In conclusion, in preterm infants, GDF15 levels show an inverse correlation with gestational age at birth, with higher levels in more preterm babies, and levels trend down postnatally. Furthermore, longitudinal GDF15 levels through 36 weeks PMA predict adverse respiratory outcomes in preterm infants.

1075. The MET Project: Distinguishing Multisystem Inflammatory Syndrome in Children from Typhus Using Artificial Intelligence

Background

Multisystem inflammatory syndrome in children (MIS-C) following SARS-CoV-2 infection shares features with other inflammatory states, notably Kawasaki Disease. The rickettsial infection murine typhus is also in the differential for MIS-C in endemic areas. As the therapeutic approaches differ, it is essential to distinguish these disorders soon after presentation, well before confirmatory serologic testing results. Our objective was to develop an algorithm to accurately predict MIS-C versus typhus.

Methods

Retrospective review extracted demographic, clinical, and laboratory features available within 6 hours of presentation for 133 MIS-C and 87 typhus patients. 33 features were broken into 44 inputs and passed through an attention module to compute importance. Inputs were then entered into machine learning algorithms as MIS-C or typhus. Patients were divided into training and test cohorts respecting proportions in the dataset. An equation was built to calculate the “MET” (MIS-C versus endemic typhus) score.

Results

MIS-C patients were younger (8.4 v 11.2 years, p< 0.0001) and the majority (71%) presented on day 4-6 of fever; most typhus patients (84%) presented with ≥6 days (mean 4.9 v 7.3 days, p< 0.0001). Typhus patients were more likely to have rash (86% v 51%, p< 0.0001) and MIS-C patients red eyes (71% v 36%, p< 0.0001), other features were similar. MIS-C patients had higher C-reactive protein levels (17.7 v 9.8 mg/dL), procalcitonin (14.0 v 0.48 ng/mL), fibrinogen (558 v 394 mg/dL) and neutrophil-to-lymphocyte ratio (12 v 3.5), all p< 0.0001, other parameters were similar. MIS-C patients were also more likely to have elevated troponin (0.48 v 0.01 ng/mL, p< 0.0001) and require intensive care (66% v 6%, p< 0.0001). A long short term memory network outperformed 6 other models (99% accuracy using all 33 elements). The MET score predicted MIS-C versus typhus with 90% accuracy using only 10 features (sensitivity 90%, specificity 90%).

Conclusion

The clinical and laboratory similarities between typhus and MIS-C present challenges, but they can be reliably distinguished using artificial intelligence with as little as 10 features. Our ongoing interprofessional collaboration aims to make the MET score readily available to clinicians for use in patient encounters.

Disclosures

Flor M. Munoz, MD, MSc, Gilead: Grant/Research Support|Moderna: DSMB|Pfizer: DSMB Tiphanie Vogel, MD, PhD, Moderna: Advisor/Consultant|Novartis: Advisor/Consultant|Pfizer: Advisor/Consultant.

Abnormalities in cardiac and inflammatory biomarkers in ambulatory subjects after COVID-19 infection

Background

Coronavirus-2019 (COVID-19) is known to affect the heart and is associated with a pro-inflammatory state. Most studies to date have focused on clinically sick subjects. Here, we report cardiac and proinflammatory biomarkers levels in ambulatory young adults with asymptomatic or mild COVID-19 infection compared to those without infection 4-8 weeks after severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) testing.

Methods

131 asymptomatic or mildly symptomatic subjects were enrolled following testing for SARS-COV-2. Fifty subjects tested negative, and 81 subjects tested positive. Serum samples were collected for measurement of C-reactive protein, ferritin, interleukin-6, NT-pro-B-type natriuretic peptide, and cardiac troponin 28-55 days after SARS-COV-2 RT-PCR testing.

Results

Biomarker levels trended higher in SARS-COV-2-positive vs negative subjects, but differences in biomarker levels or proportion of subjects with elevated biomarkers were not statistically significant with respect to SARS-COV-2 status. Among individuals with ≥ 1 comorbidity, odds of elevated CRP were greater compared to individuals without any comorbidities (odds ratio [OR] = 2.90); this effect size was increased 1.4-fold among SARS-COV-2-positive subjects (OR = 4.03). Similarly, NT-pro-BNP was associated with CVD, with the strongest association in COVID-positive individuals (OR = 16.9).

Conclusions

In a relatively young, healthy adult population, mild COVID-19 infection was associated with mild elevations in cardiac and proinflammatory biomarkers within 4-8 weeks of mild or asymptomatic COVID-19 infection in individuals with preexisting comorbidities, but not among individuals without comorbidities. For the general population of young adults, we did not find evidence of elevation of cardiac or proinflammatory biomarkers 4-8 weeks after COVID-19 infection.Clinical Perspective: This is a characterization of cardiac and proinflammatory biomarkers in ambulatory subjects following asymptomatic or mild COVID-19 infection. Young, ambulatory individuals did not have cardiac and proinflammatory biomarker elevation 4-8 weeks after mild COVID-19 infection. However, COVID-19 infection was associated with biomarker elevations in select individuals with comorbidities.Clinical study number: H-47423.

Validation of atovaquone plasma levels by liquid chromatography-tandem mass spectrometry for therapeutic drug monitoring in pediatric patients

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Atovaquone, an antiparasitic and antifungal, has potential as an anticancer agent.

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Our LC-MS/MS-based method can accurately quantify atovaquone in plasma.

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Low LOQ and small sample volume requirements add versatility to our method.

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Measuring atovaquone in plasma helps to determine the effective dose in children.

Background

Atovaquone has traditionally been used as an antiparasitic and antifungal agent, but recent studies have shown its potential as an anticancer agent. The high variability in atovaquone bioavailability highlights the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients using LC-MS/MS.

Methods

Atovaquone was extracted from a 10 µL volume of K₂-EDTA human plasma using a solution consisting of ACN: EtOH: DMF (8:1:1 v:v:v), separated using reverse-phase chromatography, and detected using a SCIEX 5500 QTrap MS system. LC-MS/MS assay performance was evaluated for precision, accuracy, carryover, sensitivity, specificity, linearity, and interferences.

Results

Atovaquone and its deuterated internal standard were analyzed using a gradient chromatographic method that had an overall cycle-time of 7.4 min per injection, and retention times of 4.3 min. Atovaquone was measured over a dynamic concentration range of 0.63 – 80 µM with a deviation within ≤ ± 5.1 % of the target value. Intra- and inter-assay precision were ≤ 2.7 % and ≤ 8.4 %, respectively. Dilutional, carryover, and interference studies were also within acceptable limits.

Conclusions

Our studies have shown that our LC-MS/MS-based method is both reliable and robust for the quantification of plasma atovaquone concentrations and can be used to determine the effective dose of atovaquone for pediatric patients treated for AML.

Dawn-to-dusk dry fasting induces anti-atherosclerotic, anti-inflammatory, and anti-tumorigenic proteome in peripheral blood mononuclear cells in subjects with metabolic syndrome

Background

Metabolic syndrome characterized by abdominal obesity, high blood pressure, elevated fasting glucose and triglyceride levels and low high-density lipoprotein cholesterol level is associated with pro-inflammatory state, increased risk for atherosclerosis, and multiple cancers. Our previous results on subjects with metabolic syndrome showed that 4-week dawn-to-dusk (sunset) dry fasting resulted in significant changes in the serum proteome and improvement in several metabolic risk factors. Peripheral blood mononuclear cells (PBMC) proteomics is a powerful tool that can provide mechanistic insights into how dawn-to-dusk dry fasting affects protein expression in metabolic pathways at cellular level. In this study, we determined whether dawn-to-dusk dry fasting would induce favorable changes in PBMC proteome in subjects with metabolic syndrome, similar to the changes induced by dawn-to-dusk dry fasting in the same subjects' serum proteome.

Methods

We conducted a prospective study on subjects with metabolic syndrome and collected blood specimens before 4-week dawn-to-dusk dry fasting, at the end of 4-week dawn-to-dusk dry fasting, and one week after 4-week dawn-to-dusk dry fasting. We performed untargeted proteomics using nano ultra-high performance liquid chromatography-tandem mass spectrometry to assess the impact of 4-week dawn-to-dusk dry fasting on PBMC proteome.

Results

There were 14 subjects with metabolic syndrome with a mean age of 59 who fasted from dawn to dusk (strict dry fasting without any liquid or food intake) for more than 14 h daily for 29 days. The quantitative proteome analysis showed that apolipoprotein B (APOB) gene protein products (GP) levels were downregulated and had the most statistical significance of the observed difference at the end of 4-week dawn-to-dusk dry fasting (P = 0.008) and one week after 4-week dawn-to-dusk dry fasting (P = 0.0004) compared with the levels before 4-week dawn-to-dusk dry fasting. The comparison between GP levels before and at the end of 4-week dawn-to-dusk dry fasting showed an alteration in the expression of genes associated with lipid and atherosclerosis pathway (P = 6.014e-4) and C-type lectin receptor signaling pathway (P = 1.064e-5). The genes that were differentially expressed in the lipid and atherosclerosis pathway were APOB (P = 0.008), CD36 (P = 0.040), CALM1, CALM2, CALM3 (P = 0.015), and HSPA8 (P = 0.047). One of the differentially expressed genes in the C-type lectin receptor signaling pathway was lymphocyte-specific protein 1 (LSP1), which showed an average of 19-fold increase at the end of 4-week dawn-to-dusk dry fasting compared with the GP levels before fasting (P = 0.004). Several GPs associated with tumor-suppressor effect (TUBB4B, LSP1, ACTR3B) were upregulated, and GPs associated with tumor-promoter effect (CD36, CALM1, CALM2, CALM3, FLOT2, PPIF) were downregulated at the end of 4-week dawn-to-dusk dry fasting or one week after 4-week dawn-to-dusk dry fasting compared with the GP levels before 4-week dawn-to-dusk dry fasting.

Conclusion

Based on our results, we conclude that in subjects with metabolic syndrome, 4-week dawn-to-dusk dry fasting induced anti-atherosclerotic, anti-inflammatory, and anti-tumorigenic PMBC proteome. Randomized, controlled clinical trials are needed to further investigate the effect of dawn-to-dusk dry fasting on subjects with chronic metabolic diseases and metabolic syndrome-induced cancers.

PSUN112 Expression of Vitamin D Receptor Pathway Genes Across Tissues of Individuals with Obesity

Introduction

Vitamin D deficiency is a substantial comorbidity in 50% of pediatric patients and is linked with poorer health outcomes in children. Vitamin D levels are inversely related to BMI. Therefore, the prevalence of children with low vitamin D levels is increasing as the prevalence of pediatric obesity increases. Pediatric patients with obesity and vitamin D deficiency also have a uniquely increased risk of metabolic syndrome, as compared to their lean peers. However, measured levels of vitamin D correlate with other physiological markers of vitamin D effects in lean individuals but not obese individuals. Since vitamin D levels measured as 25-hydroxyvitmain D (serum 25(OH)D) reflect a storage form of vitamin D, their levels may not be a true reflection of vitamin D action in the body in an obese population. The aim of this study was to provide foundational knowledge to understand if expression of vitamin D receptor (VDR)-target genes in different metabolic pathways correlate with each other in diverse tissues, and thus may be used as a reference standard for vitamin D action in the body.

Methods

We performed a secondary analysis of samples obtained from 89 obese adolescents aged 12 to 18 years old that were consented under a past IRB-approved protocol. The samples were collected at the time of bariatric surgery between 2004 and 2019. Subject data included age, gender, race/ethnicity, and BMI. Samples collected included blood, intestinal, and subcutaneous adipose tissue. The tissues were analyzed via Real Time-PCR to obtain quantitative levels of VDR-target gene expression, which included TLR4, THBD, and VDR in subcutaneous adipose tissue; and TRPV6, S100G, and VDR in intestinal tissue. Gene expression levels were normalized to the average of two housekeeping genes, GAPDH and RPLPO. Blood samples were analyzed for vitamin D levels.

Results

VDR-target gene expression of THBD, VDR, and TLR4 in subcutaneous adipose tissue was significantly correlated (p <0.05). In intestinal tissue, we also saw significant correlation between TRPV6, S100G, and VDR (p <0.05). THBD, TLR4, TRPV6, S100G, and VDR gene expression levels from the respective tissues did not correlate with circulating serum 25(OH)D levels (p >0.05).

Conclusion

These important preliminary findings show VDR-target genes have correlated expression patterns within different tissues – one which stores vitamin D (adipose) and one which doesn't (intestinal). Interestingly, the VDR-target gene expression levels correlated with each other despite the genes being involved in different metabolic pathways in diverse tissues. These findings also show that VDR-target gene expression does not correlate with circulating serum 25(OH)D levels. This discrepancy supports that 25(OH)D levels do not indicate levels of vitamin D action and may not be an appropriate indicator of vitamin D deficiency in the obese population. Thus, VDR-target gene expression levels may provide a better reference standard for vitamin D action in the body. This study may provide the first step in determining a new and more accurate biomarker for vitamin D deficiency and treatment in obesity.

Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

AACC Guidance Document on the Use of Point-of-Care Testing in Fertility and Reproduction

Background

The AACC Academy revised the reproductive testing section of the Laboratory Medicine Practice Guidelines: Evidence-Based Practice for Point-of-Care Testing (POCT) published in 2007.

Methods

A panel of Academy members with expertise in POCT and laboratory medicine was formed to develop guidance for the use of POCT in reproductive health, specifically ovulation, pregnancy, premature rupture of membranes (PROM), and high-risk deliveries. The committee was supplemented with clinicians having Emergency Medicine and Obstetrics/Gynecology training.

Results

Key recommendations include the following. First, urine luteinizing hormone (LH) tests are accurate and reliable predictors of ovulation. Studies have shown that the use of ovulation predicting kits may improve the likelihood of conception among healthy fertile women seeking pregnancy. Urinary LH point-of-care testing demonstrates a comparable performance among other ovulation monitoring methods for timing intrauterine insemination and confirming sufficient ovulation induction before oocyte retrieval during in vitro fertilization. Second, pregnancy POCT should be considered in clinical situations where rapid diagnosis of pregnancy is needed for treatment decisions, and laboratory analysis cannot meet the required turnaround time. Third, PROM testing using commercial kits alone is not recommended without clinical signs of rupture of membranes, such as leakage of amniotic fluid from the cervical opening. Finally, fetal scalp lactate is used more than fetal scalp pH for fetal acidosis due to higher success rate and low volume of sample required.

Conclusions

This revision of the AACC Academy POCT guidelines provides recommendations for best practice use of POCT in fertility and reproduction.

Comparison of Cystatin C and Creatinine-Based Equations with Measured Glomerular Filtration Rate in a Diverse Pediatric Population

BACKGROUND

Accurate assessment of kidney function is essential for early detection of kidney damage. While measured glomerular filtration rate (mGFR) is occasionally used as a reference, estimated GFR (eGFR) from serum creatinine- and cystatin C (CysC)-based equations are routinely used in clinical practice as a reliable and less invasive approach. In pediatric populations, CysC-based equations provide a closer approximation as they are independent of body composition. Limited information is available on the performance of CysC-based equations in comparison with mGFR with tracers other than iohexol. Therefore, the goal of our study was to evaluate how eGFR, based on several CysC- and creatinine-based equations, with and without race correction, relates to mGFR in a diverse pediatric population.

METHODS

A total of 43 patients (7 months to 21 years) from diverse race/ethnicity were retrospectively studied to compare the mGFR from multiple blood sample collections after intravenous tracer injection (Tc-99mDTPA) with eGFR using 9 equations. Deming regression analyses were performed to assess correlation between the mGFR and eGFRs.

RESULTS

The average mGFR for this cohort was 95.0 mL/min/1.73 m2. Race-corrected (RC) equations gave overestimated eGFR across all ethnic groups, with the lowest bias for Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) CysC-creatinine (34.14 mL/min/1.73 m2). The best correlations to mGFR, percentage of eGFR within 30% of mGFR (P30), and lowest biases were from non-race-corrected (NRC) equations Chronic Kidney Disease in Children (CKiD) (0.6460, 65.1%, 2.86 mL/min/1.73 m2), CKD-EPI CysC (0.6858, 69.8%, 11.01 mL/min/1.73 m2), and Schwartz CysC (0.6876, 79.1%, -14.00 mL/min/1.73 m2).

CONCLUSION

Overall, CysC-based equations without race correction provide a good approximation of mGFR and a less invasive alternative to monitoring kidney function in pediatric population, irrespective of race/ethnicity.

Performance evaluation of the XT MicroSlide assay pairs on the Vitros XT 7600 compared to VITROS single microslide assays on Vitros 5600

Objectives

Pediatric hospitals are always challenged by specimen volumes and thus any innovation in this realm is very welcome. With the introduction of Microslide assay pairs, we aimed to evaluate the analytical performance of the Vitros XT MicroSlide assay pairs on the Vitros XT 7600 compared to single MicroSlides.

Design

Performance characteristics included within-run precision, analytical measurable range, method comparison, and interference verification. We compared six XT MicroSlide pairs on the Vitros XT 7600 with twelve corresponding single slide assays on the Vitros 5600 system.

Results

The XT MicroSlides on Vitros XT 7600 demonstrated excellent precision, equivalent analytical measurable range, and strong method correlation with single slide assays on Vitros 5600 for most of the assays tested. Within-run CVs of the analytes ranged between 0.32% and 2.93% with between-run CV of less than 8.8% and linearity for all analytes was within the manufacturer's specified range. Interference studies showed comparable effects of hemolysis, lipemia, and bilirubin on both instruments.

Conclusions

The XT MicroSlides are comparable to the single MicroSlide assays with improved efficiency, turnaround times and lower sample volumes.

Novel Role of Ghrelin Receptor in Gut Dysbiosis and Experimental Colitis in Aging

Chronic low-grade inflammation is a hallmark of aging, which is now coined as inflamm-aging. Inflamm-aging contributes to many age-associated diseases such as obesity, type 2 diabetes, cardiovascular disease, and inflammatory bowel disease (IBD). We have shown that gut hormone ghrelin, via its receptor growth hormone secretagogue receptor (GHS-R), regulates energy metabolism and inflammation in aging. Emerging evidence suggests that gut microbiome has a critical role in intestinal immunity of the host. To determine whether microbiome is an integral driving force of GHS-R mediated immune-metabolic homeostasis in aging, we assessed the gut microbiome profiles of young and old GHS-R global knockout (KO) mice. While young GHS-R KO mice showed marginal changes in Bacteroidetes and Firmicutes, aged GHS-R KO mice exhibited reduced Bacteroidetes and increased Firmicutes, featuring a disease-susceptible microbiome profile. To further study the role of GHS-R in intestinal inflammation in aging, we induced acute colitis in young and aged GHS-R KO mice using dextran sulfate sodium (DSS). The GHS-R KO mice showed more severe disease activity scores, higher proinflammatory cytokine expression, and decreased expression of tight junction markers. These results suggest that GHS-R plays an important role in microbiome homeostasis and gut inflammation during aging; GHS-R suppression exacerbates intestinal inflammation in aging and increases vulnerability to colitis. Collectively, our finding reveals for the first time that GHS-R is an important regulator of intestinal health in aging; targeting GHS-R may present a novel therapeutic strategy for prevention/treatment of aging leaky gut and inflammatory bowel disease.

The effect of continuous venovenous hemodiafiltration on amino acid delivery, clearance, and removal in children

BACKGROUND

In critically ill children with acute kidney injury (AKI), continuous kidney replacement therapy (CKRT) enables nutrition provision. The magnitude of amino acid loss during continuous venovenous hemodiafiltration (CVVHDF) is unknown and needs accurate quantification. We investigated the mass removal and clearance of amino acids in pediatric CVVHDF.

METHODS

This is a prospective observational cohort study of patients receiving CVVHDF from August 2014 to January 2016 in the pediatric intensive care unit (PICU) of a tertiary children's hospital.

RESULTS

Fifteen patients (40% male, median age 2.0 (IQR 0.7, 8.0) years) were enrolled. Median PICU and hospital lengths of stay were 20 (9, 59) and 36 (22, 132) days, respectively. Overall survival to discharge was 66.7%. Median daily protein prescription was 2.00 (1.25, 2.80) g/kg/day. Median daily amino acid mass removal was 299.0 (174.9, 452.0) mg/kg body weight, and median daily amino acid mass clearance was 18.2 (13.5, 27.9) ml/min/m², resulting in a median 14.6 (8.3, 26.7) % protein loss. The rate of amino acid loss increased with increasing dialysis dose and blood flow rate.

CONCLUSION

CVVHDF prescription and related amino acid loss impact nutrition provision, with 14.6% of the prescribed protein removed. Current recommendations for protein provision for children requiring CVVHDF should be adjusted to compensate for circuit-related loss. A higher resolution version of the Graphical abstract is available as Supplementary information.

Maximum Dose Food Challenges Reveal Transient Sustained Unresponsiveness in Peanut Oral Immunotherapy (POIMD Study)

BACKGROUND

The maximum tolerated dose of peanut protein following peanut oral immunotherapy (POIT) is unknown because most research studies have not examined very high thresholds.

OBJECTIVE

To define the maximum dose tolerated by patients on POIT and severity of allergic reactions after a 1-month period of treatment discontinuation.

METHODS

In a phase 2 3-year POIT open-label study, we enrolled participants age 5 to 13 years with a 1-year build-up period followed by a 2-year daily maintenance dose of 3900 mg with assessment of the maximum tolerated dose using double-blind placebo-controlled food challenges (DBPCFCs) of 26,225 mg cumulative dose of peanut protein. The DBPCFC was performed at baseline, after 12-month build-up, at 2 year of maintenance, and after a 1-month period of treatment discontinuation. Biomarkers were assessed every 6 weeks for the first 6 months of therapy. A general linear mixed model was used for analysis.

RESULTS

The mean maximum cumulative tolerated dose after 12 months increased by 12,063 mg (P < .001) (n = 12), slightly decreased during maintenance (n = 11), and significantly decreased by 7593 mg after avoidance for 1 month (P = .03) (n = 6). Biomarker analysis revealed decreases in cytokine expression within the first 6 weeks of initiation of POIT and decreased peanut-IgG₄ and increased cytokine expression after 1 month of discontinuation. The DBPCFC reaction severity, examined through a symptom score with 1 point for each defined symptom, decreased after 12 months, but did not significantly change after 1 month of POIT discontinuation.

CONCLUSIONS

The evaluation of POIT and sustained unresponsiveness by maximum tolerated dose by DBPCFCs in this small phase 2 trial showed that desensitization is diminished, with 100% loss of tolerated dose after 1 month of avoidance following 3 years of treatment.

SARSCoV-2 serostatus amongst vaccinated employees at a pediatric hospital system

To gain insights on the heterogeneity of immune responses to vaccination against SARS-CoV-2 and to identify factors that could make individuals vulnerable to infection due to lack of response to vaccination, our hospital started offering free voluntary post-antibody testing against the spike protein IgG for all fully vaccinated employees.

Post-vaccination response against SARS-CoV-2 was assessed using the FDA-EUA approved VITROS anti-SARS-CoV-2 IgG immunometric assay specific to the spike protein.

Out of a total of 3266 antibody tests performed in fully vaccinated Texas Children’s, 99.4% had a positive antibody response to the spike protein. From the 21 employees (0.6%) that had a negative response, 66.7% reported taking immunosuppressive drugs and/or biologics.

Our data shows that most of the employees tested at our institution mounted an immune response to the immunogen in the vaccine. Post-vaccination antibody testing against SARS-CoV-2 can provide useful information to guide decisions about future vaccine doses.

Convalescent plasma in hospitalized pediatric and obstetric coronavirus disease 2019 (COVID-19) patients

BACKGROUND

Published data on coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) use in children and obstetric patients are limited. We describe a single-center experience of hospitalized patients who received CCP for acute COVID-19.

METHODS

A retrospective review of children 0-18-years-old and pregnant patients hospitalized with laboratory-confirmed acute COVID-19 who received CCP from March 1, 2020 to March 1, 2021 was performed. Clinical and laboratory data were collected to assess the safety of CCP administration. Antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were measured in the CCP products and in patients before transfusion and at various time points post-transfusion. Correlation between the administered SARS-CoV-2 administered versus the SARS-CoV-2 anti-spike immunoglobulin response in patient serum was assessed.

RESULTS

Twenty-two children and ten obstetric patients were eligible. Twelve pediatric and eight obstetric patients had moderate disease and ten pediatric and two obstetric patients had severe disease. Five pediatric patients died. Eighteen of 37 (48.6%) CCP titers that were measured met US Food and Drug Administration (FDA) criteria for high immunoglobulin G (IgG) antibody titer. There were no complications with transfusion. High-titer CCP showed a positive correlation with rise in patient total immunoglobulin levels only in obstetric patients but not in pediatric patients. Among pediatric patients, the median serum antibody level increased over time after transfusion.

CONCLUSIONS

Coronavirus 2019 convalescent plasma was administered safely to our patients. Our study suggested that CCP did not interfere with endogenous antibody production. The antibody titer of CCP correlated with post-transfusion response only in obstetric patients. Randomized trials in pediatric and obstetric patients are needed to further understand how to dose CCP and evaluate efficacy.

548. Convalescent Plasma in Hospitalized Pediatric and Obstetric patients with COVID-19

Background

Published data on COVID-19 convalescent plasma (CCP) use in children and obstetric patients is limited. We describe a single-center experience of hospitalized patients who received CCP for acute COVID-19.

Methods

We performed a retrospective review of children 0-18-years-old and pregnant patients hospitalized with laboratory-confirmed acute COVID-19 who received CCP from March 1st, 2020 to March 1st, 2021. Clinical and laboratory data were collected to assess the safety of CCP administration. Antibodies to SARS-CoV-2 were measured before and at various timepoints post CCP transfusion. Correlation between SARS-CoV-2 immunoglobulin administered versus the SARS-CoV-2 anti-Spike immunoglobulin response in patient serum was assessed.

Results

Twenty-two children and 10 obstetric patients were eligible. 12 pediatric and 8 obstetric patients had moderate disease and 10 pediatric and 2 obstetric patients had severe disease. 5 pediatric patients died. 18/37 (48.6%) CCP units that were measured met FDA criteria for a high IgG titer. There were no complications with transfusion based on CDC, NHSN Biovigilance Component: Hemovigilance Module Surveillance Protocol. Two pediatric patients had fevers a few hours after CCP with low suspicion for a transfusion reaction. Median SARS-CoV-2 anti-spike antibody levels of pediatric patients post-transfusion for 0-7 days was 80.6AU/mL (range: 2-1070), 8-21 days was 180AU/mL (range: 12-661) and >21 days was 210AU/mL (range: 4.1-1220). For obstetric patients, post-transfusion antibody levels were only obtained 0-7 days post-transfusion with median 45AU/mL (range: 9.5-100). High-titer CCP showed a positive correlation with rise in patient immunoglobulin levels only in the obstetric patients but not in pediatric patients.

Conclusion

CCP was administered safely to our moderately to severely ill pediatric and obstetric patients. Among pediatric patients, the median serum antibody level increased over time after transfusion and suggested that CCP did not interfere with the endogenous antibody production. Antibody dose of high-titer CCP correlated with post-transfusion response in only obstetric patients. Randomized trials in pediatric and obstetric patients are needed to further understand how to dose CCP and evaluate efficacy.

Disclosures

Jun Teruya, MD, PhD, Apelo Consulting Pvt. Ltd (Consultant)Hemosonics (Other Financial or Material Support, Honorarium) Flor M. Munoz, MD, Biocryst (Scientific Research Study Investigator)Gilead (Scientific Research Study Investigator)Meissa (Other Financial or Material Support, DSMB)Moderna (Scientific Research Study Investigator, Other Financial or Material Support, DSMB)Pfizer (Scientific Research Study Investigator, Other Financial or Material Support, DSMB)Virometix (Other Financial or Material Support, DSMB)

SARS-CoV-2 anti-spike antibodies after vaccination in pediatric heart transplantation: A first report

Background

BACKGROUND: There is a paucity of data regarding the antibody response to SARS-CoV-2 vaccination in children after solid organ transplant.

METHODS

We retrospectively reviewed the SARS-CoV-2 Anti–Spike IgG antibodies measured following SARS-CoV-2 vaccination at our pediatric heart transplant (HTx) center.

RESULTS

Among patients (median age 17.1 years) in whom antibody testing was performed (median 118 days post-vaccine completion), a SARS-CoV-2 Anti–Spike IgG antibody was detected in 28 of 40 (70%) post-HTx recipients (median antibody level 10.9 AU/ml). Neutropenia, diabetes mellitus, and previous use of rituximab were associated with absence of a detectable antibody. All 7 post-HTx patients with a known pre-vaccination SARS-CoV-2 viral infection had a detectable SARS-CoV-2 Anti–Spike IgG. All 12 vaccinated pre-HTx patients had a detectable antibody (median antibody level 11.6 AU/ml) including 5 patients that maintained detectable antibodies post-HTx. There were no cases of myocarditis among the total of 17 pre-HTx and 81 post-HTx patients that underwent SARS-CoV-2 vaccination.

CONCLUSION

Our data suggest that a significant proportion of pediatric HTx recipients have no detectable antibody response after SARS-CoV-2 vaccination and support the recommendation to complete the vaccination series prior to HTx in those pediatric patients waiting for HTx.

Activation of the Innate Immune System in Children With Irritable Bowel Syndrome Evidenced by Increased Fecal Human β-Defensin-2

BACKGROUND & AIMS

The role of the innate immune system in functional gastrointestinal pain disorders is unclear. We investigated the role of β-defensin-2 and gut permeability in childhood irritable bowel syndrome (IBS) and functional abdominal pain (FAP) symptom generation.

METHODS

Fecal β-defensin-2 (and in a subset, gut permeability) was measured in children with IBS (n = 116), FAP (n = 33), and healthy control (HC) children (n = 72). IBS and FAP patients were recruited from tertiary and primary care, and HCs were recruited from primary care.

RESULTS

β-defensin-2 concentration was greater in children with IBS (P = .003) and FAP (P = .03) than in HCs. β-defensin-2 was greater in girls with IBS than female HCs (P = .007) and in girls with IBS vs boys with IBS (P = .036). There was no difference by sex in the FAP and HC groups. For the entire cohort, β-defensin-2 correlated with multiple pain symptoms. In the IBS group, β-defensin-2 correlated with pain interference (P = .014). No correlation with pain was found in the FAP or HC group. Gut permeability was greater in the IBS vs the FAP and HC groups (P = .038). For the entire cohort, permeability correlated with the number of pain episodes (P = .041) and interfering pain episodes (P = .049). For the entire cohort there was a correlation between β-defensin-2 and permeability (P = .003), with borderline correlation in the IBS group (P = .086). For the cohort and IBS and HC groups, the number of bowel movements was modestly inversely related to fecal β-defensin-2 concentrations.

CONCLUSIONS

Increased fecal β-defensin-2 concentration in children with IBS suggests activation of the innate immune system in some, which, along with increased gut permeability, appears related to abdominal pain symptoms. Sex is an important variable in interpreting β-defensin-2 concentration in children with IBS.

Analytical and clinical performance of cPass neutralizing antibodies assay

Serological tests for SARS-CoV-2 are a critical component of disease control strategies. SARS-CoV-2 serology tests used in clinical diagnostic should not accurately evaluate total levels the antibodies but also closely correlate with neutralizing antibodies titers.

However, only limited data is available reporting correlation of neutralization antibody assays with commercial high-throughput serological assays widely used in clinical laboratories.

We performed evaluation of the GenScript cPass neutralizing antibody detection assay, to assess its value for routine clinical use to measure neutralizing titers in patients who recovered from coronavirus disease 2019 (COVID-19) or have been vaccinated. We tested its clinical performance against the commonly used Ortho Vitros IgG assay.

Our combined data shows that GenScript cPass neutralizing antibody assay has satisfactory analytical and clinical performance and good correlation with Ortho Vitros IgG, supporting its use as a tool for accurate SARS-COV-2 immune surveillance of recovered or vaccinated individuals.

Probiotic VSL#3 Treatment Reduces Colonic Permeability and Abdominal Pain Symptoms in Patients With Irritable Bowel Syndrome

Background: Little is known regarding the clinical impact of treatment and treatment duration of probiotic VSL#3 on gut and microbiome function in irritable bowel syndrome (IBS). As part of a safety trial, we assessed the effect of VSL#3 treatment duration on abdominal pain, stooling, gut permeability, microbiome composition and function.

Methods: Adults with IBS were randomized into an open label trial to receive the probiotic VSL#3 for 4 or 8 weeks. Adverse events, abdominal pain, and stooling patterns were recorded daily. Gut permeability, fecal bile acid levels, and microbiome composition were profiled at baseline and after treatment.

Results: Fifteen subjects completed the trial (4-week: n = 8; 8-week: n = 7). Number of pain episodes decreased in both groups (P = 0.049 and P = 0.034; 4- vs. 8-week, respectively). Probiotic organisms contained in VSL#3 were detected in feces by whole shotgun metagenomic sequencing analysis and relative abundances of Streptococcus thermophilus, Bifidobacterium animalis, Lactobacillus plantarum, and Lactobacillus casei subsp. paraccasei correlated significantly with improved abdominal pain symptoms and colonic permeability at study completion. Although abdominal pain correlated significantly with the detection of probiotic species at study completion, a composite view of gut microbiome structure showed no changes in community diversity or composition after VSL#3 treatment.

Conclusions: Probiotic organisms identified in stool correlated significantly with improvement in colonic permeability and clinical symptoms, prompting future studies to investigate the mechanistic role of VSL#3 and colonic permeability in IBS pathophysiology in a larger randomized controlled trial.

Clinical Trial Registration:www.clinicaltrials.gov, Identifier: NCT00971711.

An African American Male Patient with Rare Type B Insulin Resistance Syndrome

Syndromes of severe insulin resistance can result from mutations in the insulin receptor gene or autoantibodies to the insulin receptor. The type B syndrome of insulin resistance results from autoantibodies to the insulin receptor and occurs predominantly in women under age 50 years. Here we report on a 64 year old African American man with systemic lupus erythematosus (SLE) and acanthosis nigricans who had severe insulin resistance requiring up to 5000 units of insulin per day. He was diagnosed with type B insulin resistance syndrome based on his clinical presentation and demonstration of autoantibodies to the insulin receptor in his serum. This case study underscores the importance of assaying for autoantibodies to the insulin receptors especially in African American patients with severe insulin resistance and diabetes requiring excessive doses of insulin, in the setting of an autoimmune disease like SLE. It also behooves reference laboratories to develop and offer this assay because these patients have a very high mortality.

Lower blood malondialdehyde is associated with past pesticide exposure: findings in Gulf War illness and healthy controls

BACKGROUND

Malondialdehyde (MDA) is a candidate general marker of oxidative stress (OS). We sought to assess the relation of MDA to Gulf War illness (GWI) and to a variety of exposures.

METHODS

This is an observational study involving subjects from Southern California recruited from October 2011 to May 2014. MDA was assessed in 81 participants (41 GWI-cases, 40 controls). General and Gulf-specific exposures were elicited. MDA case-control comparison was restricted to 40 matched pairs. The potential association between MDA and exposures was assessed using regression analyses. Gulf-specific exposures were incorporated into a case-specific model.

RESULTS

Plasma MDA was significantly lower in GWI-cases than controls. Composite pesticide and fuel-solvent exposures negatively predicted MDA in the total sample, as well as in the analyses that included either GWI-cases or controls only. Self-reported exposure to organophosphate (OP) nerve gas was a strong predictor for lower MDA level in veterans with GWI.

CONCLUSION

Past pesticide exposures predicted lower MDA in both veterans with GWI and in healthy controls.

Effects of Team Size and a Decision Support Tool on Healthcare Providers' Workloads in Simulated Neonatal Resuscitation: A Randomized Trial

INTRODUCTION

Optimal resuscitation team size for workload distribution among team members is not known. In addition, decision support tools (DSTs) are available to improve team performance, but the effect on workload is not known. Because increased workload can impair performance, we aimed to determine whether team size or use of a DST alters workload in healthcare providers (HCPs) while performing neonatal resuscitation.

METHODS

We report a substudy of a randomized, 2 × 2 factorial design study using 109 Neonatal Resuscitation Program-trained HCPs. Healthcare providers were randomized to 1 of 4 permutations, including team size of 2 versus 3 and using DST versus memory alone while performing 2 simulated neonatal resuscitations. The HCPs' workload was assessed by the National Aeronautics and Space Administration Task Load Index obtained after each scenario. Mixed effects linear models compared the effect of team size and DST use on National Aeronautics and Space Administration Task Load Index scores.

RESULTS

When all team members were combined, there was an increased workload in teams of 2 HCPs compared with teams of 3 and was primarily due to an increase in workload on the team leaders. Decision support tool use increased workload for the other team members in the first of the 2 scenarios but did not increase workload in the second scenario.

CONCLUSIONS

Teams of 2 HCPs reported a higher workload compared with teams of 3 HCPs. Decision support tool use can increase workload for other team members when first introduced as a new task. This study highlights the need to consider factors that negatively affect mental workload when determining the composition of a resuscitation team.