Dried Blood Spots Research Articles

A simplified metabolomic analysis of dried blood spots in breast cancer patients

Breast cancer (BC) is among the most commonly diagnosed cancers. Besides mammography, breast ultrasonography and the routinely monitored protein markers, the variations of small molecular metabolites in blood may be of great diagnostic value. This study aimed to quantify specific metabolite markers with potential application in BC detection. The study enrolled 50 participants, 25 BC patients and 25 healthy controls (CTRL). Dried blood spots (DBS) were utilized as biological media and were quantified via a simplified liquid chromatography tandem mass spectrometry (LC-MS/MS) method, used in expanded newborn screening. The targeted metabolomic analysis included 12 amino acids and 32 acylcarnitines. Statistical analysis revealed a significant variation of metabolic profiles between BC patients and CTRL. Among the 44 metabolites, 18 acylcarnitines and 10 amino acids remained significant after Bonferroni correction, showing increase or decrease and enabled classification of BC patients and CTRL. The well-established LC-MS/MS protocol could provide results within few minutes. Therefore, the combination of an easy-to-handle material-DBS and LC-MS/MS protocol could facilitate BC screening/diagnosis and in the next step applied to other cancer patients, as well.

Self-Sampling by Adolescents at Home: Assessment of the Feasibility to Successfully Collect Blood Microsamples by Inexperienced Individuals.

Blood microsampling has increasingly attracted interest in the past decades as a more patient-centric sampling approach, offering the possibility to collect a minimal volume of blood following a finger or arm prick at home. In addition to conventional dried blood spots (DBS), many different devices allowing self-sampling of blood have become available. Obviously, the success of home-sampling can only be assured when (inexperienced) users collect samples of good quality. Therefore, the feasibility of six different microsampling devices to collect capillary blood by inexperienced adolescents at home was evaluated. Participants (n = 95) were randomly assigned to collect blood (dried or liquid) at different time points using four of six different self-sampling devices (i.e., DBS, Mitra volumetric absorptive microsampling (VAMS), Capitainer B, Tasso M20, Minicollect tube and Tasso+ serum separator tube (SST)). The quality of the samples was visually inspected and analytically determined. Moreover, the participants' satisfaction was assessed via questionnaires. Although a majority succeeded based on the visual inspection, the success rate differed largely between the different devices. In general, the lowest success rate was obtained for the Minicollect tubes, although there is an opportunity and need for improvement for the other self-sampling devices as well. Hence, this also emphasizes the importance to assess the quality of samples collected by the target population prior to study initiation. In addition, visual classification by a trained individual was confirmed based on assessment of the analytical variability between replicates. Finally, self-sampling at home was overall (very) positively received by the participants.

Retrospective analysis of reference intervals for dried blood spot based ms/ms newborn screening programs in Chinese preterm neonates: a nationwide study

ObjectivesAlthough recent discoveries regarding the biomarkers of newborn screening (NBS) programs by tandem mass spectrometry (MS/MS) highlight the critical need to establish reference intervals (RIs) specifically for preterm infants, no such RIs has been formally published yet. This study addressed the gap by offering a comprehensive set of reference intervals (RIs) for preterm neonates, and illustrating the dynamic changes of each biomarker with age.Design and methodsThe NBS data of 199,693 preterm newborns (< 37 weeks of gestation) who met the inclusion and exclusion criteria from the NNSCP database were included in study analysis. The birth weight stratified dynamic trend of each biomarker were captured by their concentrations over age. Reference partitions were determined by the method of Harris and Boyd. RIs, corresponding to the 2.5th and 97.5th percentiles, as well as the 0.5th, 25th, 50th, 75th and 99.5th percentiles were calculated using a non-parametric rank approach.ResultsIncreasing birth weight is associated with an elevation in the levels of arginine, citrulline, glycine, leucine and isobarics, methionine, ornithine, phenylalanine, and valine, whereas the levels of alanine, proline and tyrosine decrease. Additionally, two short-chain acylcarnitines (butyrylcarnitine + isobutyrylcarnitine and isovalerylcarnitine + methylbutyrylcarnitine) and a median-chain acylcarnitine (octenoylcarnitine) decrease, while four long-chain acylcarnitines (tetradecanoylcarnitine, palmitoylcarnitine, palmitoleylcarnitine and oleoylcarnitine) increase with increasing birth weight. Age impacts the levels of all MS/MS NBS biomarkers, while sex only affects the level of malonylcarnitine + 3-hydroxybutyrylcarnitine (C3-DC + C4-OH) in very low birth weight preterm neonates.ConclusionThe current study developed reference intervals (RIs) specific to birth weight, age, and/or sex for 35 MS/MS biomarkers, which can help in the timely evaluation of the health and disease of preterm neonates.

The Asian Fabry Cardiomyopathy High-Risk Screening Study 2 (ASIAN-FAME-2): Prevalence of Fabry Disease in Patients with Left Ventricular Hypertrophy.

Background: Fabry disease (FD) is a rare X-linked lysosomal storage disorder that commonly manifests cardiovascular complications. We aimed to assess the prevalence of FD in a Chinese population with left ventricular hypertrophy (LVH) whilst implementing a gender-specific screening approach. Methods: Patients with LVH, defined as a maximum thickness of the left ventricular septal/posterior wall ≥ 13 mm, were considered eligible. All patients with hypertrophic cardiomyopathy (HCM) were excluded. Plasma α-galactosidase (α-GLA) enzyme activity was assessed using a dried blood spot test. Males with low enzyme activity underwent genetic testing to confirm a diagnosis of FD whereas females were screened for both α-GLA and globotriaosylsphingosine concentration and underwent genetic analysis of the GLA gene only if testing positive for ≥1 parameter. Results: 426 unrelated patients (age = 64.6 ± 13.0 years; female: male = 113:313) were evaluated. FD was diagnosed in 3 unrelated patients (age = 69.0 ± 3.5 years, female: male = 1:2) and 1 related female subject (age = 43 years). Genetic analyses confirmed the late-onset cardiac variant GLA c.640-801G>A (n = 3) and the missense variant c.869T>C associated with classic FD (n = 1). Cardiac complications were the only significant findings associated with the late-onset c.640-801G>A mutation, manifesting as mild or severe concentric LVH. In contrast, the classic c.869T>C mutation FD exhibited multisystemic manifestations in addition to severe concentric LVH. Conclusions: The prevalence of FD is lower in Chinese patients with LVH when HCM is excluded. The pathological variant c.640-801G>A remains the most common cause of late-onset FD, while the detection of FD in females can be improved by utilizing a gender-specific screening method.

Screening for Fabry disease in patients on Hemodialysis.

Fabry disease is an under-recognized X-linked lysosomal storage disorder characterized by the accumulation of trihexosylceramides in multifarious tissues, leading to end-organ damage, including progressive renal failure. Antecedent screening studies worldwide have shown inconsistent prevalence in the hemodialysis population. We conducted this study to screen for Fabry disease in patients undergoing dialysis at a tertiary care hospital. All patients undergoing dialysis were screened with a gal assay using dried blood spots (DBS) on filter paper using the fluorescence method. Patients with positive DBS test results were further tested for underlying mutations. A total of 112 patients (64.3% males and 35.7% females) on dialysis were screened. Nineteen patients (13 males and 6 females) were found to have low enzyme activity on DBS. Further mutation analysis confirmed that one female patient had Fabry disease. The mutation detected was a heterozygous missense variation in exon 7 of the GLA gene, which resulted in the amino acid substitution of histidine for arginine at codon 363 (p.Arg363His). Subsequent screening of the family members revealed that the son of the patient was asymptomatic and carried the same genotypic mutation. Genetic counseling was performed, and enzyme replacement therapy was offered to both patients. Fabry disease remains underdiagnosed, especially in high-risk populations such as those undergoing dialysis. DBS is a convenient and effective screening tool for Fabry disease. Facilities should be augmented for similar screening studies in the dialysis population.

Temporal Assessment of Protein Stability in Dried Blood Spots.

The use of protein biomarkers in blood for clinical settings is limited by the cost and accessibility of traditional venipuncture sampling. The dried blood spot (DBS) technique offers a less invasive and more accessible alternative. However, protein stability in DBS has not been well evaluated. Herein, we deployed a quantitative LC-MS/MS system to construct proteomic atlases of whole blood, DBSs, plasma, and blood cells. Approximately 4% of detected proteins' abundance was significantly altered during blood drying into blood spots, with overwhelming disturbances in cytoplasmic fraction. We also reported a novel finding suggesting a decrease in the level of membrane/cytoskeletal proteins (SLC4A1, RHAG, DSC1, DSP, and JUP) and an increase in the level of proteins (ATG3, SEC14L4, and NRBP1) related to intracellular trafficking. Furthermore, we identified 19 temporally dynamic proteins in DBS samples stored at room temperature for up to 6 months. There were three declined cytoskeleton-related proteins (RDX, SH3BGRL3, and MYH9) and four elevated proteins (XPO7, RAN, SLC2A1, and SLC29A1) involved in cytoplasmic transport as representatives. The instability was governed predominantly by hydrophilic proteins and enhanced significantly with an increasing storage time. Our analyses provide comprehensive knowledge of both short- and long-term storage stability of DBS proteins, forming the foundation for the widespread use of DBS in clinical proteomics and other analytical applications.

Fabry disease Enzyme Enhancement on migalastat Study: FEES

BackgroundThere is limited information on the α-galactosidase A (α-Gal-A) in vivo response in Fabry patients receiving migalastat. In this single centre study, we evaluated changes from baseline in α-Gal A activity, lyso-Gb3 and other assessments in patients on migalastat. Results79 patients were recruited (48 M:31F; median duration receiving migalastat 3.8 years [range = 0.4–14.9 years]). N215S was the commonest genotype in males (67 %) and females (29 %). Leukocyte α-Gal-A showed a positive change from baseline in males (n = 4; median = 20.05); females (n = 8; median = 26). Of these, 3 males and 1 female had N215S (median = 16.7), while 7 females and 1 male had other genotypes (median = 26). No significant changes observed in plasma α-Gal-A. Cross-sectional analysis of post-baseline data confirmed leukocyte α-Gal-A enhancement in males (n = 47; median = 20); females (n = 30; median = 72); N215S (n = 41; median = 29) and other genotypes (n = 36; median = 36.5). Plasma and dried blood spot (DBS) lyso-Gb3 correlated at baseline and post-baseline (r = 0.77 and r = 0.96; p=<0.0001). ConclusionsIn the 12 patients with paired data, there was a median enzyme enhancement of 17.4 (relative change = 2.54) and 33 (relative change = 0.87) in males and in females, respectively. The cross-sectional post-baseline data in 47 patients corroborated leukocyte α-Gal-A enhancement on migalastat. Plasma and DBS lyso-Gb3 correlated well supporting DBS utility for disease monitoring.

Effectiveness of integrating HIV prevention within sexual reproductive health services with or without peer support among adolescents and young adults in rural KwaZulu-Natal, South Africa (Isisekelo Sempilo): 2 × 2 factorial, open-label, randomised controlled trial

Approximately 200 000 South Africans acquired HIV in 2021 despite the availability of universal HIV test and treat and pre-exposure prophylaxis (PrEP). The aim of this study was to test the effectiveness of sexual and reproductive health services or peer support, or both, on the uptake of serostatus neutral HIV services or reduction of sexually transmissible HIV. We did an open-label, 2 × 2 randomised factorial trial among young people in a mostly rural area of KwaZulu-Natal, South Africa. Inclusion criteria included being aged 16-29 years, living in the mapped geographical areas that were accessible to the area-based peer navigators, being willing and able to provide informed consent, and being willing to provide a dried blood spot for anonymous HIV testing and HIV viral load measurement at 12 months. Participants were randomly allocated by computer-generated algorithm to one of four groups: those in the standard-of-care group were referred to youth-friendly services for differentiated HIV prevention (condoms, universal HIV test and treat with antiretroviral therapy, and PrEP if eligible); those in the sexual and reproductive health services group received baseline self-collected specimens for sexually transmitted infection (STI) testing and referral to integrated sexual and reproductive health and HIV prevention services; those in the peer support group were referred to peer navigators for health promotion, condom provision, and facilitation of attendance for differentiated HIV prevention services; and those in the final group received a combination of sexual and reproductive health services and peer support. Coprimary outcomes were linkage to clinical services within 60 days of enrolment, proportion of participants who had sexually transmissible HIV at 12 months after enrolment, and proportion of sampled individuals who consented to participation and gave a dried blood spot for HIV testing at 12 months. Logistic regression was used for analyses, and adjusted for age, sex, and rural or peri-urban area of residence. This study is registered with ClinicalTrials.gov (NCT04532307) and is closed. Between March 2, 2020, and July 7, 2022, 1743 (75·7%) of 2301 eligible individuals were enrolled and followed up. 12-month dried blood spots were collected from 1168 participants (67·0%). The median age of the participants was 21 years (IQR 18-25), 51·4% were female, and 51·1% had secondary level education. Baseline characteristics and 12-month outcome ascertainment were similar between groups. 755 (43·3%) linked to services by 60 days. 430 (49·8%) of 863 who were in the sexual reproductive health services group were linked to care compared with 325 (36·9%) of 880 who were not in the sexual and reproductive health services group (adjusted odds ratio [aOR] 1·68; 95% CI 1·39-2·04); peer support had no effect: 385 (43·5%) of 858 compared with 370 (43·1%) of 885 (1·02, 0·84-1·23). At 12 months, 227 (19%) tested ELISA-positive for HIV, of whom 41 (18%) had viral loads of 400 copies per mL; overall prevalence of transmissible HIV was 3·5%. 22 (3·7%) of 578 participants in the sexual and reproductive health services group had transmissible HIV compared with 19 (3·3%) of 590 not in the sexual and reproductive health services group (aOR 1·12; 95% CI 0·60-2·11). The findings were also non-significant for peer support: 21 (3·3%) of 565 compared with 20 (3·3%) of 603 (aOR 1·03; 95% CI 0·55-1·94). There were no serious adverse events or deaths during the study. This study provides evidence that STI testing and sexual and reproductive health services create demand for serostatus neutral HIV prevention in adolescents and young adults in Africa. STI testing and integration of HIV and sexual health has the potential to reach those at risk and tackle unmet sexual health needs. US National Institute of Health, Bill & Melinda Gates Foundation, and 3ie.

Challenges recruiting and retaining people at risk for HIV who use methamphetamine in a randomized PrEP adherence trial in Seattle, WA.

Methamphetamine is associated with increased HIV risk and suboptimal adherence to pre-exposure prophylaxis (PrEP). Interventions to support PrEP adherence for people who use methamphetamine are needed. We evaluated peer navigation to support adherence among people initiating PrEP who use methamphetamine. The HIV Prevention in Methamphetamine Users (HMU!) study enrolled participants from May 2018-January 2022 in Seattle, WA, and followed them for 6 months. Surveys collected sociodemographic, drug use, and sexual behavior data at enrollment, month 3, and month 6. Dried blood spots (DBS) were collected at months 1, 3, and 6 to measure PrEP adherence. We enrolled 21 participants of a target sample of 40, of whom 20 were prescribed PrEP. Nine participants (43%) received peer navigation and 12 (57%) received standard of care or text messaging. At baseline, most participants reported at least weekly methamphetamine use (17, 81%) and condomless receptive anal intercourse (CRAI) (16, 76%). One-third reported CRAI with a partner with HIV. Among those who provided a DBS, 78% and 50% had results commensurate with ≥4 pills/week at the month 3 and 6 visit, respectively. More than half of those prescribed PrEP completed a month 6 visit (11, 55%). Retention was not associated with peer support compared to standard of care or text messaging (p = .20). We enrolled half our target sample size despite extensive recruitment efforts. As expected, participants had challenges with PrEP adherence and persistence. While peer navigation interventions should be studied further, additional interventions are likely needed to support PrEP uptake, adherence, and persistence among people who use methamphetamine.

HIV-1 infection kinetics, drug resistance, and long-term safety of pre-exposure prophylaxis with emtricitabine plus tenofovir alafenamide (DISCOVER): week 144 open-label extension of a randomised, controlled, phase 3 trial

Data characterising the long-term use and safety of emtricitabine plus tenofovir disoproxil fumarate as daily oral pre-exposure prophylaxis (PrEP) are scarce and there are uncertainties regarding the value of routine HIV-1 RNA testing during oral PrEP follow-up. The DISCOVER trial was a randomised, controlled, phase 3 trial in which cisgender men and transgender women aged 18 years and older with a high likelihood of acquiring HIV were recruited from 94 clinics in Europe and North America and randomly assigned to receive either emtricitabine plus tenofovir disoproxil fumarate (200/25 mg) tablets daily, with matched placebo tablets, or emtricitabine plus tenofovir alafenamide (200/300 mg) tablets daily, with matched placebo tablets, for at least 96 weeks. After completion of the trial, participants were offered enrolment in this 48-week open-label extension study of emtricitabine plus tenofovir alafenamide. In participants diagnosed with HIV during the randomised and open-label phases of the study, we characterised HIV-1 test results and measured HIV-1 RNA viral load retrospectively when available. Adherence based on tenofovir diphosphate concentrations in dried blood spots and genotypic resistance were assessed in participants diagnosed with HIV. Safety assessments included adverse events, laboratory parameters, and, in a subset of participants, bone mineral density. HIV-1 incidence in participants initially randomly assigned to receive emtricitabine plus tenofovir alafenamide was estimated using a Poisson distribution. Changes from baseline in safety endpoints were described in participants assigned to received emtricitabine plus tenofovir alafenamide and in those who switched from emtricitabine plus tenofovir disoproxil fumarate during the open-label phase. This trial is registered with ClinicalTrials.gov, NCT02842086, and is ongoing. Between Sept 13, 2016, and June 30, 2017, 5399 participants were enrolled and randomly assigned in DISCOVER. 2699 were assigned to receive emtricitabine plus tenofovir disoproxil fumarate and 2700 were assigned to receive emtricitabine plus tenofovir alafenamide, of whom 2693 and 2694, respectively, received at least one dose of study drug. 2115 (79%) assigned to emtricitabine plus tenofovir disoproxil fumarate switched to emtricitabine plus tenofovir alafenamide in the open-label phase, and 2070 (77%) continued with emtricitabine plus tenofovir alafenamide in the open-label phase. As of data cutoff (Dec 10, 2020), after 15 817 person-years of follow-up, 27 new HIV-1 diagnoses were observed across the total study period, with three occurring during the open-label phase. In participants who were initially assigned to emtricitabine plus tenofovir alafenamide, the incidence was 0·13 per 100 person-years (95% CI 0·061-0·23; ten of 2670). Stored plasma samples were available for 23 of 27 participants, including 22 with incident infection. In four (17%) of 23 participants, retrospective testing detected HIV-1 RNA before serological HIV-1 test positivity; one was a suspected baseline infection. Of the three incident cases, all three were non-adherent to PrEP and none developed drug resistance. Among participants taking emtricitabine plus tenofovir alafenamide for up to 144 weeks, markers of glomerular filtration and proximal renal tubule dysfunction (β2-microglobulin to creatinine ratio and retinol-binding protein to creatinine ratio) improved or remained stable at 144 weeks compared with baseline, bone mineral density in hip and lumbar spine increased or remained stable from baseline to week 144 (n=191), cholesterol and glucose concentrations remained stable, and median bodyweight increased by less than 1 kg per year. In participants who switched from emtricitabine plus tenofovir disoproxil fumarate during the open-label phase (2115 [79%] of 2693), markers of glomerular filtration and proximal renal tubule dysfunction improved or remained stable, bone mineral density increased, cholesterol concentrations increased, glucose concentrations were similar, and median bodyweight increased more compared with those who remained on emtricitabine and tenofovir alafenamide. Routine HIV-1 RNA testing for follow-up of individuals on daily oral PrEP provides modest additional clinical benefit. Long-term use of emtricitabine and tenofovir alafenamide as daily oral PrEP is safe and well tolerated and can be an especially appropriate choice for people with bone or renal morbidities. Gilead Sciences.

Towards needed improvements in inherited metabolic medicine in adulthood: The SIMMESN adult metabolic working group and MetabERN Joint Position Statement

Inherited metabolic disorders (IMDs), previously considered as a paediatric sub-specialisation are more and more prevalent in adults, thanks to improved survival, and the expansion of diagnostic tools detecting attenuated–late onset forms in adulthood. Italy is one of the countries with the highest number of IMDs screened by dry blood spots in neonates, allowing them to receive early treatments and to reach adult age. Despite this, awareness of IMDs is still low by the adult medical community, with difficulties in transition and transfer of patients to adult services and unmet patient needs. In 2022, a collaboration between the adult metabolic working group of the Italian Society for the Study of Inherited Metabolic Disorders and Neonatal Screening (SIMMESN) and the European Reference Network for Hereditary Metabolic Disorders (MetabERN) was established to face problems linked to IMDs in adulthood. “The Statement of Udine” was developed to guide further steps towards improvements in inherited metabolic medicine in adults, referencing the experience from the UK. The aim of this paper is to present “The Statement of Udine” explaining its background and its possible applications.

HCV prevalence and phylogenetic characteristics in a cross-sectional, community study of young people who inject drugs in New York City: Opportunity for and threats to HCV elimination.

In the United States, the opioid epidemic has led many young people who use opioids to initiate injection drug use, putting them at risk for hepatitis C virus (HCV) infection. However, community surveys to monitor HCV prevalence among young people who inject drugs (YPWID) are rare. As part of Staying Safe (Ssafe), a trial to evaluate an HCV-prevention intervention, a community-recruited sample of 439 young people who use opioids (ages 18-30) in New York City (NYC) were screened from 2018 to 2021. Screening procedures included a brief verbal questionnaire, a visual check for injection marks, onsite urine drug testing, rapid HCV antibody (Ab) testing, and dried blood spot (DBS) collection. DBS specimens were sent to a laboratory for HCV RNA testing and phylogenetic analysis to identify genetic linkages among HCV RNA-positive specimens. Multivariable logistic regression was used to assess associations between HCV status (Ab and RNA) and demographics and drug use patterns. Among the 330 participants who reported injecting drugs (past 6 months), 33% (n = 110) tested HCV Ab-positive, 58% of whom (n = 64) had HCV RNA-positive DBS specimens, indicating active infection. In multivariable analysis, visible injection marks (AOR = 3.02; p < 0.001), older age (AOR = 1.38; p < 0.05), and female gender (AOR = 1.69; p = 0.052) were associated with HCV Ab-positive status. Visible injection marks were also associated with HCV RNA-positive status (AOR = 5.24; p < 0.01). Twenty-five percent of RNA-positive specimens (14/57) were genetically linked. The relatively low prevalence of active infection suggests the potential impact of treatment-as-prevention in reducing HCV prevalence among YPWID. Targeted community serosurveys could help identify actively infected YPWID for treatment, thereby reducing HCV incidence and future transmissions.

Antibody Response to Symptomatic Infection With SARS-CoV-2 Omicron Variant Viruses, December 2021-June 2022.

We describe humoral immune responses in 105 ambulatory patients with laboratory-confirmed SARS-CoV-2 Omicron variant infection. In dried blood spot (DBS) collected within 5 days of illness onset and during convalescence, we measured binding antibody (bAb) against ancestral spike protein receptor binding domain (RBD) and nucleocapsid (N) protein using a commercial multiplex bead assay. Geometric mean bAb concentrations against RBD increased by a factor of 2.5 from 1258 to 3189 units/mL and by a factor of 47 against N protein from 5.5 to 259 units/mL between acute illness and convalescence; lower concentrations were associated with greater geometric mean ratios. Paired DBS specimens may be used to evaluate humoral response to SARS-CoV-2 infection.

Genetic variation present in the CYP3A4 gene in Ni-Vanuatu and Kenyan populations in malaria endemicity

Cytochrome P450 3A4 (CYP3A4) enzyme is involved in the metabolism of about 30 % of clinically used drugs, including the antimalarials artemether and lumefantrine. CYP3A4 polymorphisms yield enzymatic variants that contribute to inter-individual variation in drug metabolism. Here, we examined CYP3A4 polymorphisms in populations from malaria-endemic islands in Lake Victoria, Kenya, and Vanuatu, to expand on the limited data sets. We used archived dried blood spots collected from 142 Kenyan and 263 ni-Vanuatu adults during cross-sectional malaria surveys in 2013 and 2005–13, respectively, to detect CYP3A4 variation by polymerase chain reaction (PCR) and sequencing. In Kenya, we identified 14 CYP3A4 single nucleotide polymorphisms (SNPs), including the 4713G (CYP3A4∗1B; allele frequency 83.9 %) and 19382A (CYP3A4∗15; 0.7 %) variants that were previously linked to altered metabolism of antimalarials. In Vanuatu, we detected 15 SNPs, including the 4713A (CYP3A4∗1A; 88.6 %) and 25183C (CYP3A4∗18; 0.6 %) variants. Additionally, we detected a rare and novel SNP C4614T (0.8 %) in the 5′ untranslated region. A higher proportion of CYP3A4 genetic variance was found among ni-Vanuatu populations (16 %) than among Lake Victoria Kenyan populations (8 %). Our work augments the scarce data sets and contributes to improved precision medicine approaches, particularly to anti-malarial chemotherapy, in East African and Pacific Islander populations.

The Impact of Rheumatoid Arthritis on First Nations and How We Can Work With Communities to Prevent It.

Rheumatoid arthritis (RA) is prevalent in many Indigenous North American First Nations (FN) and tends to be seropositive, familial, and disabling, as well as associated with highly unfavorable outcomes such as early mortality. The risk of developing RA is based on a perfect storm of gene-environment interactions underpinning this risk. The gene-environment interactions include a high frequency of shared epitope encoding HLA alleles, particularly HLA-DRB1*1402, in the background population, and prevalent predisposing environmental factors such as smoking and periodontal disease. Together, these provide a compelling rationale for an RA prevention agenda in FN communities. Our research team has worked in partnership with several FN communities to prospectively follow the first-degree relatives of FN patients with RA, with the aim of better understanding the preclinical stages of RA in this population. We have focused on specific features of the anticitrullinated protein antibodies (ACPA) and other proteomic biomarkers as predictors of future development of RA. These studies have now led us to consider interventions having a favorable risk-benefit ratio if applied at a stage prior to a hypothetical "point of no return," when the autoimmunity potentially becomes irreversible. Based on a supportive mouse model and available human studies of curcumin, omega-3, and vitamin D supplements, we are undertaking studies where we screen communities using dried blood spot technology adapted for the detection of ACPA, and then enrolling ACPA-positive individuals in studies that use a combination of these supplements. These studies are guided by shared decision-making principles.

Development and evaluation of a candidate reference measurement procedure for detecting 17α-hydroxyprogesterone in dried blood spots using isotope dilution liquid chromatography tandem mass spectrometry

17α-Hydroxyprogesterone (17α-OHP) quantification in dried blood spots (DBS) is essential for newborn screening for congenital adrenal hyperplasia (CAH), which is challenging due to its low physiological concentration. The high false-positive rates of immunoassays necessitate the development of more accurate methods. Liquid chromatography tandem mass spectrometry (LC-MS/MS) offers increased specificity and sensitivity, yet standardized procedures for 17α-OHP measurement are required for clinical application. A candidate reference measurement procedure (cRMP) using isotope dilution LC-MS/MS was developed for 17α-OHP quantification in DBS. By utilizing stable isotope-labeled D8-17α-OHP as an internal standard, the cRMP was optimized, covering sample preparation, calibration, and LC-MS/MS analysis. The method performance was validated across several parameters, including precision, accuracy, specificity, detection limits, and matrix effects. Clinical applicability was further assessed through the establishment of reference intervals for healthy newborns. The developed cRMP exhibited a linear range of 1.00 to 80.00 ng/mL for 17α-OHP, with detection and quantification limits of 0.14 ng/mL and 0.52 ng/mL, respectively. Inter- and intraday precision demonstrated coefficients of variation within 1.27 to 5.69%. The recovery rates and matrix effects were well within acceptable limits, ensuring method reliability. Clinical application showed distinct reference intervals for healthy newborns that were unaffected by sex but influenced by weight and gestational age. This method significantly enhances CAH diagnostic accuracy in newborns, providing a valuable tool for clinical laboratories and improving newborn screening program standardization and traceability.

Advancing towards practice: A novel LC-MS/MS method for detecting retinol in dried blood spots

BackgroundTo date, clinical laboratories face challenges in quantifying retinol from DBS samples. Disputes arise throughout the whole detection process, encompassing the storage condition, the release strategy as well as the selection of internal standards. MethodsWe incubated DBS with ascorbic acid solution. Then, retinol-d4 in acetonitrile was introduced to incorporate isotopic internal standard and promote protein precipitation. Afterward, sodium carbonate solution was added to ionize cytochromes (such as bilirubin), which amplified the difference of their hydrophobicity to retinol. Subsequently, cold-induced phase separation could be facilitated to separate retinol from the impurities. In the end, the upper layer was injected for LC-MS/MS analysis. ResultsBy comparing the detected retinol content in whole blood and DBS samples prepared from the same volume, we confirmed the established pretreatment was capable to extract most of retinol from DBS (recovery >90 %). Thereafter, we verified that within DBS, retinol possessed satisfying stability without antioxidation. Indoor-light exposure and storage duration would not cause obvious degradation (<10 %). Following systematic validation, the established method well met the criteria outlined in the relevant guidelines. After comparing with detected DBS results to the paired plasma samples, 54 out of 60 met the acceptance limit for cross-validation of ±20 %. ConclusionsWe realized precise quantification of retinol from one 3.2 mm DBS disc. By circumventing conventional antioxidation, liquid-liquid/solid-phase extraction and organic solvent evaporation, the pretreatment could be completed within 15 min consuming only minimal amounts of low-toxicity chemicals (ascorbic acid, acetonitrile, and sodium carbonate). We expect this contribution holds the potential to significantly facilitate the evaluation of patients' vitamin A status by using DBS samples in the future.

COVID-19 vaccine immunogenicity and safety surrounding fourth and subsequent vaccine doses in patients with hematologic malignancies

BackgroundImmune response to COVID-19 vaccine is diminished in patients with hematologic malignancy. There is limited data regarding response to vaccine doses in these patients. PurposeTo quantify the humoral immune response engendered by 4th and subsequent doses of SARS-CoV-2 vaccination as measured by anti-Spike (anti-S) antibody levels, based on dried blood spot (DBS) testing, in patients with hematologic malignancies. Anti-S binds to the spike protein of the SARS-CoV-2 virus and is indicative of vaccine immunogenicity. MethodsWe conducted a prospective study of hematologic malignancies between August 2021 and January 2023 at 12 sites across Canada. Participants were followed longitudinally and submitted finger-prick DBS cards at set intervals associated with vaccination. Samples were processed via high throughput ELISA assay to detect serum antibodies against nucleocapsid (N) and spike (S) proteins. ResultsWe obtained 3071 samples on 790 unique patients. Of these, 372 unique participants with 1840 samples had anti-S results available post-4th, 5th or 6th COVID-19 vaccine dose and were included for analysis.Three hundred thirty-three patients of the 372 participants submitted a DBS sample post 4th dose. Of these, 257 patients (77.2%) had a positive anti-S antibody. A total of 198 patients had paired samples pre- and post-dose 4, of which 59 (29.7%) had a negative anti-S antibody pre-dose 4. Of these, 20 (33.4%) developed positive anti-S antibody post-dose 4. One hundred forty-nine patients submitted a DBS sample post-dose 5. Of these, 135 patients (90.6%) had positive anti-S antibody. A total of 52 had paired samples pre- and post-dose 5. Six (8.7%) had a negative anti-S antibody pre-dose 5, of which two (33.3%) developed positive anti-S antibody post-dose 5.Of these 372 patients, 123 (34%) reported COVID-19 infection and 4 (1%) had a COVID-19 related hospitalization. There were no reported deaths from COVID-19. ConclusionsThis prospective cohort study showed that humoral immune response improved with subsequent doses of COVID-19 vaccines.

Clozapine levels and outcomes in Serbian patients with treatment-resistant psychotic disorders previously treated without measuring clozapine levels (CLOSER)

Clozapine remains the only pharmacological treatment option for treatment-resistant schizophrenia. Therapeutic drug monitoring (TDM) of clozapine is recommended, although evidence for the therapeutic range of 350–600 ng/ml is limited. In various countries including Serbia, TDM of clozapine is not routinely performed.This study evaluated the distribution of clozapine levels and their relationship with clinical outcomes in Serbian patients who had not undergone prior TDM. 140 Patients with treatment-resistant schizophrenia and schizo-affective disorder were enrolled. Clozapine levels were measured by dried blood spot (DBS) analysis. Side effects were evaluated by GASS-c, severity of symptoms and functional impairment with WHODAS, CGI-S and GAF.Of the patients, 51.2% had subtherapeutic levels, 24.8% were in the therapeutic window, and 24% had supratherapeutic levels. Clozapine levels showed no association with side effects and a weak positive association with symptom severity and functional impairment. No serious side effects were observed in patients with clozapine levels surpassing 1000 ng/ml (n = 8).Based on these findings, we propose that the upper limit of the therapeutic range should not be regarded as an absolute barrier, and guidelines should allow for a personalized approach when prescribing clozapine.

Feasibility and acceptability of collecting dried blood spots (DBS) from children after vaccination during supplementary immunization activities to estimate measles and rubella seroprevalence

Nested serosurveys within routine service delivery platforms such as planned supplemental immunization activities (SIAs) provide an opportunity to collect information that can be used to answer valuable questions on the effectiveness and efficiency of the delivery model to inform future activities. However, integrating research data collection in SIAs is rarely done due to concerns it will negatively impact the program. We conducted a serosurvey nested within the November 2020 measles-rubella SIA integrated with the Child Health Week activities in Zambia to evaluate this approach. In-depth interviews with the study teams and vaccination campaign staff at the vaccination sites were conducted. Recorded interviews were transcribed, transcripts were coded and then grouped into themes based on a process evaluation framework. A multi-methods analytical approach was used to assess the feasibility and acceptability of collecting dried blood spots from children during the SIA. This included a quantitative assessment of participant enrollment. The serosurvey successfully enrolled 90% of children from Child Health Week due to close coordination and teamwork between the vaccination teams and serosurvey team, in addition to substantial social mobilization efforts. Continually adjusting the sampling interval that was used to select eligible children allowed us to enroll throughout the SIA and capture a representative sample of children in attendance although it was challenging for the staff involved. As vaccination programs aim to tailor their approaches to reach the hardest-to-reach children, embedding research questions in SIAs will allow evaluation of the successes and challenges and compare alternative approaches. Lessons learned from this experience collecting data during an SIA can be applicable to future research activities embedded in SIAs or other delivery platforms.