Antibody Response to SARS-CoV-2 Infection and Vaccination in COVID-19-naïve and Experienced Individuals.

Understanding the magnitude of responses to vaccination during the ongoing SARS-CoV-2 pandemic is essential for ultimate mitigation of the disease. Here, we describe a cohort of 102 subjects (70 COVID-19-naïve, 32 COVID-19-experienced) who received two doses of one of the mRNA vaccines (BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)). We document that a single exposure to antigen via infection or vaccination induces a variable antibody response which is affected by age, gender, race, and co-morbidities. In response to a second antigen dose, both COVID-19-naïve and experienced subjects exhibited elevated levels of anti-spike and SARS-CoV-2 neutralizing activity; however, COVID-19-experienced individuals achieved higher antibody levels and neutralization activity as a group. The COVID-19-experienced subjects exhibited no significant increase in antibody or neutralization titer in response to the second vaccine dose (i.e., third antigen exposure). Finally, we found that COVID-19-naïve individuals who received the Moderna vaccine exhibited a more robust boost response to the second vaccine dose (p = 0.004) as compared to the response to Pfizer-BioNTech. Ongoing studies with this cohort will continue to contribute to our understanding of the range and durability of responses to SARS-CoV-2 mRNA vaccines.

Performance of a new molecular assay for the detection of gastrointestinal pathogens.

INTRODUCTION: Conventional diagnostic laboratory algorithms for determining the cause of infectious gastroenteritis include culture, biochemical identification and immunoassays. In addition, multiplex PCR-based testing has advanced into the gastroenterology diagnostic arena in recent years. AIM: The purpose of this study was to evaluate the performance of a new molecular test (Diagnostics Solutions Laboratory GI-MAP) for the detection of bacterial and parasitic pathogens in stool samples spiked with known organisms. METHODOLOGY: Faeces from a healthy human subject were pooled into a standard matrix and screened for the absence of bacteria, parasites and Helicobacter pylori antigen. Once confirmed negative single faecal aliquots from the matrix were spiked with solely one pathogen-type from a panel of 14 bacterial pathogens or one of 2 parasitic pathogens at a density of 5×106 organisms ml-1. Sixteen spiked samples in appropriate transport media were sent to two testing labs, specifically a reference site using the PCR-based BioFire FilmArray Gastrointestinal Panel, and a second lab using the GI-MAP assay. Seven negative control samples comprised solely of stool matrix were also submitted. RESULTS: Significant variability was found when the GI-MAP assay was used to test normal stool matrix with and without known bacteria and parasites at densities well within the expected limits of detection. The GI-MAP assay displayed a sensitivity of 80 % and a specificity of only 26 % due to many false positive results. This assay also reported quantitative numbers for pathogens. The BioFire FilmArray Gastrointestinal Panel achieved a sensitivity and specificity of 100 %. CONCLUSION: The highly variable results for the GI-MAP assay were unexpected due to the precise pre-spike analysis and the overall maturation of nucleic acid amplification methods within the industry. Problematic to this assay is the poor level of specificity displayed by this assay reporting the presence of several pathogens, which could cause clinicians to treat with antibacterial and/or antiparasitic agents in the absence of any true pathogens.

The High Prevalence of Vitamin D Insufficiency in Cord Blood in Calgary, Alberta (APrON-D Study).

OBJECTIVE: Vitamin D is important in promoting healthy pregnancy and fetal development. We undertook this study to measure 25-hydroxyvitamin D in maternal and cord blood and to identify maternal factors related to vitamin D status in Calgary. METHODS: Blood samples collected at the time of delivery from the Alberta Pregnancy Outcomes and Nutrition study cohort (ApronStudy.ca) participants were processed for plasma and assayed using liquid chromatography mass spectrometry methodology for 25(OH)D3. RESULTS: Ninety-two pairs of maternal and cord blood samples were obtained. The prevalence of 25(OH)D3 insufficiency-25(OH)D3 <75 nmol/L-was 38% and 80% in women and neonates, respectively. Vitamin D supplementation was the only clinical factor associated with 25(OH)D3 sufficiency, and the odds of sufficiency were 3.75 (95% CI 1.00 to 14.07) higher for women and 5.27 (95% CI 1.37 to 20.27) when over 2000 IU/day were used. CONCLUSION: Using liquid chromatography mass spectrometry, we demonstrated a very high prevalence of vitamin D insufficiency in cord blood and that the use of high dose vitamin D was associated with greater odds of sufficiency in pregnant women and cord blood in Alberta.

The Current Recommended Vitamin D Intake Guideline for Diet and Supplements During Pregnancy Is Not Adequate to Achieve Vitamin D Sufficiency for Most Pregnant Women.

BACKGROUND: The aims of this study were to determine if pregnant women consumed the recommended vitamin D through diet alone or through diet and supplements, and if they achieved the current reference range vitamin D status when their reported dietary intake met the current recommendations. METHODS: Data and banked blood samples collected in second trimester from a subset of 537 women in the APrON (Alberta Pregnant Outcomes and Nutrition) study cohort were examined. Frozen collected plasma were assayed using LC-MS/MS (liquid chromatography-tandem mass spectrometry) to determine 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3 concentrations. Dietary data were obtained from questionnaires including a Supplement Intake Questionnaire and a 24-hour recall of the previous day's diet. RESULTS: Participants were 87% Caucasian; mean (SD) age of 31.3 (4.3); BMI 25.8 (4.7); 58% were primiparous; 90% had education beyond high school; 80% had a family income higher than CAN $70,000/year. 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3) were identified in all of the 537 plasma samples;3-epi-25(OH)D3 contributed 5% of the total vitamin D. The median (IQR) total 25(OH)D (D2+D3) was 92.7 (30.4) nmol/L and 20% of women had 25(OH)D concentration < 75 nmol/L. The median (IQR) reported vitamin D intake from diet and supplements was 600 (472) IU/day. There was a significant relationship between maternal reported dietary vitamin D intake (diet and supplement) and 25(OH)D and 3-epi-25(OH)D3 concentrations in an adjusted linear regression model. CONCLUSIONS: We demonstrated the current RDA (600 IU/ day) may not be adequate to achieve vitamin D status >75 nmol/L in some pregnant women who are residing in higher latitudes (Calgary, 51°N) in Alberta, Canada and the current vitamin D recommendations for Canadian pregnant women need to be re-evaluated.

Plasma 3-Epi-25-Hydroxycholecalciferol Can Alter the Assessment of Vitamin D Status Using the Current Reference Ranges for Pregnant Women and Their Newborns.

BACKGROUND: Vitamin D is critical for healthy pregnancies and normal fetal development. It is important to accurately ascertain vitamin D status in mothers and their newborns to establish the optimal vitamin D concentration during pregnancy. There are many different metabolites and epimers of vitamin D in peripheral blood and controversy as to the importance of epimers in estimating vitamin D status in maternal and infant health. OBJECTIVES: We undertook this study to measure 25-hydroxyvitamin D metabolites and epimers and their relations in maternal and cord blood and to evaluate the impact of the inclusion of epimers on assessing vitamin D status. METHODS: We performed a substudy in a longitudinal cohort of pregnant women and their infants in Alberta, Canada [APrON (Alberta Pregnancy Outcomes and Nutrition) Study]. Maternal and cord blood plasma collected at the time of newborn delivery was stored at -70°C until testing and assayed for 25-hydroxyergocalciferol [25(OH)D2], 25-hydroxycholecalciferol [25(OH)D3], and 3-epi-25-hydroxycholecalciferol [3-epi-25(OH)D3] by using LC-tandem mass spectrometry. The effect of 3-epi-25(OH)D3 on estimates of vitamin D adequacy was explored by using McNemar's chi-square test at both recommended thresholds of 50 and 75 nmol/L. RESULTS: Ninety-two pairs of maternal and cord blood samples were obtained. 3-Epi-25(OH)D3 was detected in all samples, comprising 6.0% and 7.8% of 25(OH)D3 in maternal and cord blood, respectively. Positive correlations were found between 25(OH)D3 and 3-epi-25(OH)D3 for both maternal and cord blood (maternal blood: r = 0.34, P = 0.01; cord blood: r = 0.44, P = 0.01). In addition, regression analysis showed a significant association between vitamin D supplementation and 3-epi-25(OH)D3 in maternal and cord blood (ß: 0.423; 95% CI: 0.173, 0.672). When 3-epi-25(OH)D3 was not included in plasma vitamin D estimations, 38% of women and 80% of neonates were classified as having an insufficient concentration (<75 nmol/L); however, with 3-epi-25(OH)D3 included, the estimates of insufficiency were significantly lower: 33% and 73% for women and neonates, respectively. CONCLUSIONS: Using LC-MS/MS we showed the presence of 3-epi-25(OH)D3 in all samples of pregnant women and their cord blood, and when the 3-epimer was included in the estimation of status the prevalence of vitamin D insufficiency (<75 nmol/L) was significantly lower. Our data suggest that the high use of dietary supplements in this group of women contributes to 3-epi-25(OH)D3 concentrations in both maternal and cord blood. Further research on the role of the epimers in characterizing vitamin D status in pregnancy and infancy is imperative.

A novel intraoral diabetes screening approach in periodontal patients: results of a pilot study.

BACKGROUND: This pilot study examines whether a novel diabetes screening approach using gingival crevicular blood (GCB) could be used to test for hemoglobin A1c (HbA1c) during periodontal visits. METHODS: Finger-stick blood (FSB) samples from 120 patients and GCB samples from those patients with adequate bleeding on probing (BOP) were collected on special blood collection cards and analyzed for HbA1c levels in a laboratory. The Pearson correlation coefficient was used to measure correlation between FSB and GCB HbA1c values for 75 paired FSB and GCB samples. A receiver-operator characteristic curve (ROC) analysis was performed to determine an optimal GCB HbA1c criterion value for a positive diabetes screen. RESULTS: For the 75 paired samples, the Pearson correlation coefficient was 0.842. The ROC analysis identified a criterion value of 6.3% for the GCB HbA1c test with high sensitivity (0.933) and high specificity (0.900), corresponding to FSB HbA1c values ≥6.5% (in the diabetes range). Using this GCB HbA1c criterion value for 27 additional paired samples, in which there was an unidentified component observed to coelute within the elution window of GCB HbA1c in the laboratory, there was agreement between FSB and GCB values for 24 of the pairs according to whether both were within or outside of the diabetes range. CONCLUSION: Using a criterion value of 6.3%, GCB samples are acceptable for HbA1c testing to screen for diabetes in most persons with BOP at the GCB collection site.

Total homocysteine, diet, and lipid profiles in type 1 and type 2 diabetic and nondiabetic adolescents.

BACKGROUND AND RESEARCH OBJECTIVE: Limited research is available on the possible differences in the cardiovascular risk factors of total homocysteine (tHcy), dietary energy, and lipids among adolescents with type 1 diabetes mellitus (DM), type 2 DM, or healthy controls. This study's primary aim was to compare the dietary energy and the intake of macronutrients and micronutrients of folate, and vitamins B6 and B12, as well as lipids and tHcy for adolescents with type 1 DM, type 2 DM, and healthy non-DM controls. SUBJECTS AND METHODS: This secondary analysis of the merging of 2 datasets included the following adolescents: 50 with type 1 DM, 14 with type 2 DM, and 53 controls. Mean ages for those with type 1 versus type 2 DM were 15.2 +/- 1.9 versus 16.1 +/- 1.9 years, respectively. Mean age for the controls was 16.5 +/- 1.0 years. Variables included fasting tHcy and lipids, and 24-hour dietary recalls for macronutrients and micronutrients. Hemoglobin A1c was obtained for those with DM. Statistical analyses included one-way analyses of variance, Pearson correlations, and stepwise regression. RESULTS AND CONCLUSIONS: Adolescents with type 1 DM had the lowest tHcy values (P <.05), which were reflective of the limited extant research with this population. Lipid profiles and dietary energy did not differ significantly among the 3 groups. Hemoglobin A1c was related to total cholesterol and triglycerides in those with type 1 DM, confirming the importance of promoting better metabolic control in lipid management for these youth. Future research should continue to explore the validity of tHcy and lipids as predictors of CV risks for youth with type 1 and type 2 DM.

Measurement of prostate-specific antigen by use of a novel blood collection and analytical system.

BACKGROUND: Prostate-specific antigen (PSA) is widely used in the detection and monitoring of prostate cancer. We developed a system for the self-collection and transport of capillary whole blood for PSA analysis, with the goal of reducing phlebotomy visits and, thus, increasing the access and utilization of PSA in prostate cancer screening and monitoring. METHODS: The blood collection device [BIOSAFE Blood Transport System (BTS] collects 70 microL of blood through a heparin-coated material into 200 microL of stabilizing solution. The diluted whole blood is used for measurement of PSA by a modified version of the Hybritech Tandem-MP PSA Assay. Results were compared for matched samples of professionally and self-collected BTS blood and for matched BTS samples sera from blood collected by venipuncture. Imprecision for the whole-blood PSA measurement was estimated from analysis of whole-blood controls in duplicate, twice per day, over 20 days. RESULTS: BTS samples (n = 140) collected by a qualified healthcare professional compared with serum samples yielded the regression equation: y =1.02x + 0.04 (S(yx) = 0.35; r = 0.99). Comparison of the results for samples (n = 128) collected by the patient without professional assistance with serum samples yielded: y = 1.08x + 0.02 (S(yx) = 0.31; r = 0.99). The between-run CVs at 0.069, 0.53, 2.9, and 10.7 microg/L were 21%, 6.0%, 3.5%, and 3.8%, respectively. PSA was stable in BTS samples stored for 21 days at 18-24 degrees C and for 7 days at 37 degrees C. CONCLUSION: The BIOSAFE BTS system allows accurate and convenient measurement of circulating PSA by a precise method for diluted whole blood.