In-house Assay Research Articles

Snapshot of Anti-SARS-CoV-2 IgG Antibodies in COVID-19 Recovered Patients in Guinea.

Background: Because the regular vaccine campaign started in Guinea one year after the COVID-19 index case, the profile of naturally acquired immunity following primary SARS-CoV-2 infection needs to be deepened. Methods: Blood samples were collected once from 200 patients (90% of African extraction) who were recovered from COVID-19 for at least ~2.4 months (72 days), and their sera were tested for IgG antibodies to SARS-CoV-2 using an in-house ELISA assay against the Receptor Binding Domain (RBD) of the SARS-CoV-2 spike1 protein (RBD/S1-IH kit). Results: Results revealed that 73% of sera (146/200) were positive for IgG to SARS-CoV-2 with an Optical Density (OD) ranging from 0.13 to 1.19 and a median value of 0.56 (IC95: 0.51-0.61). The median OD value at 3 months (1.040) suddenly decreased thereafter and remained stable around OD 0.5 until 15 months post-infection. The OD median value was slightly higher in males compared to females (0.62 vs. 0.49), but the difference was not statistically significant (p-value: 0.073). In contrast, the OD median value was significantly higher among the 60-100 age group (0.87) compared to other groups, with a noteworthy odds ratio compared to the 0-20 age group (OR: 9.69, p-value: 0.044*). Results from the RBD/S1-IH ELISA kit demonstrated superior concordance with the whole spike1 protein ELISA commercial kit compared to a nucleoprotein ELISA commercial kit. Furthermore, anti-spike1 protein ELISAs (whole spike1 and RBD/S1) revealed higher seropositivity rates. Conclusions: These findings underscore the necessity for additional insights into naturally acquired immunity against COVID-19 and emphasize the relevance of specific ELISA kits for accurate seropositivity rates.

Assessment of an in-house IgG ELISA targeting SARS-CoV-2 RBD: Applications in infected and vaccinated individuals

The study evoluated an in-house Spike Receptor Binding Domain Enzyme-Linked Immunosorbent Assay (RBD-IgG-ELISA) for detecting SARS-CoV-2 IgG antibodies in infected and vaccinated individuals. The assay demonstrated a sensitivity of 91%, specificity of 99.25%, and accuracy of 95.13%. Precision and reproducibility were highly consistent. The RBD-IgG-ELISA was able to detect 96.25% of Polymerase chain reaction (PCR) confirmed cases for SARS-CoV-2 infection, demonstrating positive and negative predictive values of 99,18% and 91,69%, respectively. In an epidemiological survey, ELISA, lateral flow immunochromatographic assay (LFIA), and electrochemiluminescence immunoassay (ECLIA) exhibited diagnostic sensitivities of 68.29%, 63.41%, and 70.73%, respectively, along with specificities of 82.93%, 80.49%, and 80.49%, respectively. Agreement between RBD-IgG-ELISA/PCR was moderate (k index 0.512). However, good agreement between different assays (RBD-IgG-ELISA/LFIA k index 0.875, RBD-IgG-ELISA/ECLIA k index 0.901). Test performance on individuals' samples were inferior due to seroconversion time and chronicity. The IgG-RBD-ELISA assay demonstrated its effectiveness in monitoring antibody levels among healthcare professionals, revealing significant differences both before and after the administration of the third vaccine dose, with heightened protection levels observed following the third dose in five Coronavirus disease (COVID-19) vaccine regimens. In conclusion, the RBD-IgG-ELISA exhibits high reproducibility, specificity, and sensitivity, making it a suitable assay validated for serosurveillance and for obtaining information about COVID-19 infections or vaccinations.

Exploring the Chikungunya virus landscape in a dengue-endemic Brazilian area

We aimed to describe the landscape, including molecular, epidemiological, and clinical aspects of CHIKV infections in the Ribeirao Preto region, an area endemic to dengue. We randomly screened 3744 plasma samples that had undergone DENV diagnosis to evaluate CHIKV-RNA using an in-house RT-PCR assay. Positive samples were followed clinically, and RNA samples were submitted to whole genome sequencing. Seventeen cases (0.5 %) were positive for CHIKV-RNA despite being negative for DENV-RNA. Notably, half of the patients experienced prolonged arthralgia lasting more than 90 days. Compared with the healthy control group, leukopenia and thrombocytopenia were observed in all CHIKV-positive individuals with statistically significant P values (P < 0.0001 and P = 0.0003, respectively). The genomic analysis revealed that the CHIKV strains being studied are classified within the East-Central-South-African (ECSA) genotype. This analysis identified new mutations, E1: K211E and E2: V264A, while the previously known mutation E1: A226V was not detected among these strains. This study highlights the need for epidemiological surveillance and preparedness for potential CHIKV epidemics in Brazil, particularly where other arboviruses co-circulate.

Fit-for-Purpose Ki-67 Immunohistochemistry Assays for Breast Cancer

New therapies are being developed for breast cancer, and in this process, some “old” biomarkers are reutilized and given a new purpose. It is not always recognized that by changing a biomarker’s intended use, a new biomarker assay is created. The Ki-67 biomarker is typically assessed by immunohistochemistry (IHC) to provide a proliferative index in breast cancer. Canadian laboratories assessed the analytical performance and diagnostic accuracy of their Ki-67 IHC laboratory-developed tests (LDTs) of relevance for the LDTs’ clinical utility.Canadian clinical IHC laboratories enrolled in the Canadian Biomarker Quality Assurance Pilot Run for Ki-67 in breast cancer by invitation. The Dako Ki-67 IHC pharmDx assay was employed as a study reference assay. The Dako central laboratory was the reference laboratory. Participants received unstained slides of breast cancer tissue microarrays with 32 cases and performed their in-house Ki-67 assays. The results were assessed using QuPath, an open-source software application for bioimage analysis. Positive percent agreement (PPA, sensitivity) and negative percent agreement (NPA, specificity) were calculated against the Dako Ki-67 IHC pharmDx assay for 5%, 10%, 20%, and 30% cutoffs.Overall, PPA and NPA varied depending on the selected cutoff; participants were more successful with 5% and 10%, than with 20% and 30% cutoffs. Only 4 of 16 laboratories had robust IHC protocols with acceptable PPA for all cutoffs. The lowest PPA for the 5% cutoff was 85%, for 10% was 63%, for 20% was 14%, and for 30% was 13%. The lowest NPA for the 5% cutoff was 50%, for 10% was 33%, for 20% was 50%, and for 30% was 57%.Despite many years of international efforts to standardize IHC testing for Ki-67 in breast cancer, our results indicate that Canadian clinical LDTs have a wide analytical sensitivity range and poor agreement for 20% and 30% cutoffs. The poor agreement was not due to the readout but rather due to IHC protocol conditions. International Ki-67 in Breast Cancer Working Group (IKWG) recommendations related to Ki-67 IHC standardization cannot take full effect without reliable fit-for-purpose reference materials that are required for the initial assay calibration, assay performance monitoring, and proficiency testing.

Abstract PS08-09: Impact of HER2 expression dynamics on the real-world activity of trastuzumab deruxtecan for metastatic breast cancer (RELIEVE)

Abstract Background: trastuzumab deruxtecan (T-DXd) is a standard treatment for patients (pts) with HER2-positive (HER2+) and HER2-low metastatic breast cancer (MBC). HER2-low expression has been shown to be a highly unstable biomarker, and no data exists on the activity of T-DXd among pts with changes in HER2 status over time. Furthermore, limited data exists on the performance of regimens administered after progression on T-DXd. Methods: We analyzed data for pts with MBC receiving T-DXd at Dana-Farber Cancer Institute between 7/2017 - 2/2023 and at Duke Cancer Center between 3/2020 - 4/2022. The disease was categorized HER2+ if IHC 3+ or ISH-amplified at any time point; HER2-negative cases were categorized as HER2-low (IHC 2+/ISH- or IHC 1+) or HER2-0 (IHC 0) based on the last biopsy before T-DXd; the HER2 status for the primary tumor and at first metastatic diagnosis were also collected. We determined time to next treatment (TTNT), overall survival (OS), toxicities with T-DXd, TTNT based on dynamic HER2 status and TTNT with post-T-DXd regimens. Genomic data was available for 58 pts using an in-house NGS assay on archival tumor samples. Results: A total of 191 pts were included in the analysis (126 HER2+, 44 HER2-low, 21 HER2-0). Median age at metastatic diagnosis was 50.9 (range 21 - 78), 26% had de-novo MBC and 38% had history of brain metastases before T-DXd. The proportion of hormone receptor (HR)-positive tumors based on the last biopsy prior to T-DXd was 53% in HER2+, 68% in HER2-low and 57% in HER2-0; pts within each cohort had received a median of 2 prior lines of chemotherapy before T-DXd (range 0 - 9). With a median follow-up of 10.4 months, median TTNT was 10.4 months for HER2+, 7.6 months for HER2-low and 3.7 months for HER2-0 MBC (p &amp;lt; 0.001). Switch in HER2 status between primary tumor and pre-T-DXd biopsy significantly impacted outcomes, with the shortest TTNT observed in pts switching from HER2-low to HER2-0 (TTNT 3.0 months) compared with 5.6 months if switching from HER2-0 to HER2-low, and 9.4 months if having stable HER2-low status (p=0.006). Conversely, HER2 status switch within the metastatic setting did not impact outcomes (Table 1). No difference in TTNT was seen regardless of HR status (negative vs positive, 7.4 vs 10.2 months, p=0.25) or number of prior chemotherapies (≤2 vs &amp;gt;2, 10.1 vs 8.8 months, p=0.50). Median OS is shown in Table 1. At last follow-up, 55 pts remain on T-DXd (28.8%), 108 progressed (56.5%), 28 stopped due to toxicity (14.7%). A total of 22 pts (11.5%) developed interstitial lung disease (ILD, 6.2% grade [G]1, 3.1% G2, 1.6% G3, 0.5% G4, no G5). ILD occurred after a median of 8 months from T-DXd initiation and resolved in 63.6% of the cases, with a median time to resolution of 4 months (2 months for grade 1 events). 5 pts (2.6%) developed cardiotoxicity. T-DXd was dose reduced in 61 pts (31.9%), most often for fatigue (14.7%), nausea/vomiting (9.9%) or hematological toxicity (6.3%). Among 105 pts receiving post-T-DXd treatments, TTNT was 4 months for HER2+, 3.1 months for HER2-low and 4.3 months for HER2-0 MBC (p=0.62). Pts with HER2-negative tumors and ERBB2 hemizygous deletions (6/58, 10.3 %) had a TTNT with T-DXd of 4.1 months, vs 7.6 months without ERBB2 deletions (p=0.41). Additional biomarker data will be presented at the meeting. Conclusions: T-DXd showed promising real-world activity in pretreated pts with MBC, with the longest TTNT observed among pts with HER2+ disease or with stable HER2-low disease over time. Real world TTNT is relatively short post-T-DXd and further studies evaluating resistance mechanisms and optimal treatments in this setting are needed. Table 1 – TTNT and OS among patients with metastatic breast cancer receiving T-DXd and post-T-DXd regimens according to HER2 status The activity of T-DXd significantly differed according to the HER2 status of the disease, with the longest TTNT observed among patients with HER2+ disease (at any timepoint in time) and among patients with stable HER2-low disease over time. Regimens administered immediately after T-DXd achieved a similar performance irrespective of the HER2 status of the disease, with a TTNT ranging between 3.1 and 4.3 months. Citation Format: Paolo Tarantino, Melissa Hughes, Ross Kusmick, Laura Alder, Alyssa Pereslete, Laura Noteware, Heather Moore, Amanda Van Swearingen, Tianyu Li, Hersh Gupta, Kalie Smith, Stefania Morganti, Janet Files, Kerry Sendrick, Simone Buck, Deborah Dillon, Rinath Jeselsohn, Yvonne Li, Andrew Cherniack, Aleix Prat, Nay Nwe Nyein Chan, David Rimm, Giuseppe Curigliano, Sarah Sammons, Carey Anders, Nancy Lin, Sara Tolaney. Impact of HER2 expression dynamics on the real-world activity of trastuzumab deruxtecan for metastatic breast cancer (RELIEVE) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS08-09.

Broad-spectrum dengue virus detection using the commercial RealStar dengue RT-PCR kit 3.0 (Altona) and an in-house combined real-time RT-PCR assay

In endemic areas, the genetic diversity among co-circulating dengue virus (DENV) strains is considerable and new, highly divergent strains are identified on a regular basis. It is thus critical to ensure that molecular diagnostic tools effectively detect virus genomes even in case of important genetic variation. Here, we tested both the pan-DENV detection capacity and the limit of detection of two real-time RT-PCR assays: (i) the commercial RealStar Altona 3.0 system and (ii) a laboratory developed test (LDT) combining two RT-PCR systems in a single reaction tube (DenAllDUO). We used a panel of DENV strains representative of the genetic diversity within DENV species, combined with three in vitro transcribed RNAs as surrogates for unavailable strains corresponding to recently discovered strains with substantial genetic divergence: DENV serotype 1 (DENV-1) Brun2014, DENV-2 QML22 and DENV-4 DKE121. Both systems (i) targeted the genome 3′ untranslated region, (ii) displayed a broad detection spectrum, encompassing most of DENV species diversity, and (iii) detected the three aforementioned divergent strains. DenAllDUO detected all the strains tested, whereas the RealStar system failed to detect strains from DENV-4 genotype III. Altogether, our findings support the value of these two RT-PCR systems as part of the Dengue diagnostic arsenal.

A novel indirect ELISA for serodiagnosis of mucormycosis using antigens from Rhizopus arrhizus.

Due to a delay in diagnosis by conventional techniques and high mortality, the development of a standardised and rapid non-culture-based technique is an unmet need in pulmonary, gastrointestinal, and disseminated forms of mucormycosis. Though limited studies have been conducted for molecular diagnosis, there are no established serologic tests for this highly fatal infection. To develop and evaluate an indirect in-house enzyme-linked immunosorbent assay (ELISA) utilising antigens of Rhizopus arrhizus for detecting anti-Rhizopus antibodies (IgG and IgM) in sera of patients with mucormycosis. We extracted both secretory and mycelial Rhizopus antigens using standardised protocols. Bradford assay was used for protein quantification. We then standardised an indirect ELISA using R. arrhizus mycelial and secretory antigens (10.0 μg/mL in bicarbonate buffer pH 9.2) for detecting anti-Rhizopus IgG and IgM antibodies in patient sera. We included patients with mucormycosis, other fungal infections, and healthy controls. Antibody index value (E-value) was calculated for each patient sample. Asparagine broth culture filtrate utilising 85% ammonium sulphate salt fractionation and mycelial homogenate grown in yeast extract peptone dextrose (YPD) broth precipitated with trichloroacetic acid (TCA) yielded a large amount of good-quality protein for the assay. We included 55 patients with mucormycosis (rhino-orbito-cerebral mucormycosis [ROCM, n = 39], pulmonary [n = 15], gastrointestinal [n = 1]), 24 with other fungal infections (probable aspergillosis [n = 14], candidiasis [n = 10]), and healthy controls (n = 16). The sensitivity of the antibody test for diagnosing mucormycosis ranged from 83.6-92.7% for IgG and 72.7-87.3% for IgM, with a specificity of 91.7-92.5% for IgG and 80-82.5% for IgM. The sera from patients with other fungal infections and healthy individuals did not show significant cross-reactivity. The detection of anti-Rhizopus IgG antibody performed significantly better in comparison to IgM-based ELISA for diagnosing both ROCM (sensitivity of 84.6% vs. 69.2%) and pulmonary cases (86.6% vs. 80.0%). More extensive studies are required to confirm our findings.

Analysis of immunogenetics interlaboratory comparisons' success rates. External quality assurance system of the Spanish Society for Immunology GECLID-SEI.

For many years, transplantation outcomes were uncertain and not hopeful, until histocompatibility testing spread. Common criteria for histocompatibility assays and communications' improvement allowed an efficient organ sharing system. The possibility of organ exchanges is closely linked to the importance of interlaboratory comparisons for histocompatibility and immunogenetics methods. The external proficiency testing (EPT) systems are the most powerful quality assurance tools. They help achieve harmonization of analyses, set a standard of performance, and a common interpretation. The external quality assurance program for diagnostic immunology laboratories (Garantía Externa de Calidad para Laboratorios de Inmunología Diagnóstica, GECLID) program nowadays runs 13 external quality assurance (EQA) histocompatibility and immunogenetics schemes, with the first of them from 2011 to date: serological and molecular: low- and high-resolution human leukocyte antigen (HLA), human platelet antigen (HPA), and killer inhibitory receptor (KIR) typing(HLA-B*27, HLA-B*57:01, and coeliac disease-related HLA), cell-dependent cytotoxicity (CDC) and flow cytometry (FC) crossmatches, anti-HLA and anti-HPA antibodies, and chimerism. A total of 85 laboratories participated in this subprogram in the last 12years reporting over 1.69M results: 1.46M for anti-HLA and anti-HPA antibodies, 203.810 molecular typing data (HLA, HPA, and KIR genes), 2.372 for chimerism analyses, and 39.352 for crossmatches. Based on the European Federation for Immunogenetics (EFI) standards for EPT providers, the mean success rates ranged from 99.2% for molecular typing schemes and antibodies and 94.8% for chimerism, was 96.7% regarding crossmatches, and was 98.9% in serological typing. In 2022, 61.3% of the participating laboratories successfully passed every HLA EQA scheme, although 87.9% annual reports were satisfactory. Most penalties were due to nomenclature errors or misreporting of the risk associated to HLA and disease. This EQA confirms the reliability of HLA and immunogenetics assays in routine care. There is little heterogeneity of results of different assays used by participating laboratories, even when in-house assays are used. Reliability of test results is reasonably granted.

Comparison of rectal swabs and fecal samples for the detection of Clostridioides difficile infections with a new in-house PCR assay.

Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated diarrhea, resulting in high morbidity, mortality, and economic burden. In clinical laboratories, CDI testing is currently performed on stool samples collected from patients with diarrhea. However, the diagnosis of CDI can be delayed by the time required to collect stool samples. Barriers to sample collection could be overcome by using a rectal swab instead of a stool sample. Our study showed that CDI can be identified rapidly and reliably by a new PCR assay developed in our laboratory on both stool and rectal swab specimens. The use of PCR tests on rectal swabs could reduce the time for the detection of CDI and improve the management of this infection. It should also provide a useful alternative for infection-control practitioners to better control the spread of C. difficile.

Breakthrough Mpox Outbreak Investigation, the Delicate Balance Between Host Immune Response and Viral Immune Escape.

Limited data are available on Mpox breakthrough infections. The purpose of this study is to investigate a Mpox breakthrough outbreak in 3 vaccinated individuals. Study participants provided informed consent. Serology testing was performed in one involved individual (ID-1) using an in-house assay detecting anti-orthopoxvirus IgG. Whole genome sequencing (WGS) was carried out and compared with the reference sequence ON563414.3 ( https://www.ncbi.nlm.nih.gov/nuccore/ON563414.3/ ). Three individuals vaccinated with modified vaccinia Ankara-Bavaria Nordic contracted Mpox following one sexual intercourse event. One of them (ID-1) had received only one vaccine dose, while the other two were fully vaccinated. ID-1 presented to the sexual health clinic of the Universitair Ziekenhuis Brussel with proctitis related to Mpox. Despite one vaccination, serology testing Three months post vaccine showed absence of Mpox virus (MPXV) specific antibodies in ID-1. In contrast, 2 weeks after the sexual intercourse, seroconversion occurred. Whole genome sequencing of the isolated MPXV showed, compared with the reference sequence, a total of seven single nucleotide variants with four of them indicating protein amino-acid changes. Incomplete MPXV vaccination as well as MPXV variants might result in breakthrough infections. Preventive measures, such as MPVX vaccination, could maintain immunity in individuals with higher risk of MPXV infection, and might lower disease severity.

A validated in-house assay for HIV drug resistance mutation surveillance from dried blood spot specimens

Despite increasing scale-up of antiretroviral therapy (ART) coverage, challenges related to adherence and HIV drug resistance (HIVDR) remain. The high cost of HIVDR surveillance is a persistent challenge with implementation in resource-constrained settings. Dried blood spot (DBS) specimens have been demonstrated to be a feasible alternative to plasma or serum for HIVDR genotyping and are more suitable for lower resource settings. There is a need for affordable HIVDR genotyping assays which can amplify HIV-1 sequences from DBS specimens, particularly those with low viral loads, at a low cost. Here, we present an in-house assay capable of reliably amplifying HIV-1 protease and partial reverse transcriptase genes from DBS specimens, which covers the complete World Health Organization 2009 list of drug resistance mutations under surveillance. DBS specimens were prepared using whole blood spiked with HIV-1 at concentrations of 10,000, 5000, 1000, and 500 copies/mL (n=30 for each concentration). Specimens were tested in triplicate. A two-step approach was used consisting of cDNA synthesis followed by nested PCR. The limit of detection of the assay was calculated to be approximately 5000 (95% CI: 3200–10,700) copies/mL for the protease gene and 3600 (95% CI: 2200–10,000) copies/mL for reverse transcriptase. The assay was observed to be most sensitive with higher viral load specimens (97.8% [95% CI: 92.2–99.7]) for both protease and reverse transcriptase at 10,000 copies/mL with performance decreasing with the use of specimens with lower viral loads (46.7% [36.1–57.5] and 60.0% [49.1–70.2] at 500 copies/mL for protease and reverse transcriptase, respectively). Ultimately, this assay presents a promising opportunity for use in resource-constrained settings. Future work should involve validation under field conditions including sub-optimal storage conditions and preparation of DBS with fingerprick blood in order to accurately reflect real-world collection scenarios.

Serosurvey of Coxiella burnetii in Police Officers and Working Dogs in Brazil: Case Report and One Health Implications.

Although the Coxiella burnetii infection has been investigated in dogs, its role in human transmission remains to be fully established, particularly in close and daily human-dog contact settings, such as in Police K-9 Units. Accordingly, this study aimed to assess anti-C. burnetii antibodies in clinically healthy police officers by an in-house indirect immunofluorescence assay (IFA), and working dogs by a commercial IFA Kit, from the State Special Operations Battalion, Paraná, Southern Brazil. Overall, 1/18 (5.5%) police officers and 9/30 (30.0%; CI 95% 16.66-47.88) dogs tested seropositive to anti-C. burnetii IgG antibodies. To date, this is the highest prevalence of Q fever seropositivity among military dogs worldwide. Despite the low sampling rate, a statistically significant association was found between seropositivity and female dogs (p = 0.0492). Further studies with larger sample sizes should be conducted to establish the prevalence of Q Fever in other Brazilian K-9 Units. In summary, this study is the first to conduct a concomitant serosurvey of police officers and working dogs, and its findings should be considered a warning for cross-exposure and transmission of Coxiella burnetii among Police K-9 Units in Brazil and worldwide.

Improving Access to Anti-HDV Testing: Development and Validation of an Affordable In-House ELISA Assay.

In certain low-income nations, the hepatitis Delta virus and hepatitis B virus (HBV) pose a serious medical burden, where the prevalence of hepatitis B surface antigen (HBsAg) is greater than 8%. Especially in rural places, irregular diagnostic exams are the main restriction and reason for underestimation. Utilizing serum samples from a Pakistani isolate, an internal ELISA for the quick identification of anti-HDV was created, and the effectiveness of the test was compared to a commercial diagnostic kit. HDV-positive serum samples were collected, and a highly antigenic domain of HDAg antigen was derived from them. This antigenic HDAg was expressed in a bacterial expression system, purified by Ni-chromatography, and confirmed by SDS-PAGE and Western blot analysis. The purified antigen was utilized to develop an in-house ELISA assay for anti-HDV antibody detection of the patient's serum samples at very low cost. Purified antigens and positive and negative controls can detect anti-HDV (antibodies) in ELISA plates. The in-house developed kit's efficiency was compared with that of a commercial kit (Witech Inc., USA) by the mean optical density values of both kits. No significant difference was observed (a P value of 0.576) by applying statistical analysis. The newly developed in-house ELISA is equally efficient compared to commercial kits, and these may be useful in regular diagnostic laboratories, especially for analyzing local isolates.

Abstract LB432: Identification of novel drug targets using the ADAPT biotargeting system on FFPE tissue from patients with glioblastoma multiforme

Abstract Glioblastoma Multiforme (GBM) is one of the most aggressive and lethal brain tumor types with a five-year survival rate of 6.9%. In 2023, more than 14,490 Americans were expected to receive a diagnosis. Although great progress has been achieved in protein target identification and treatment over the last few years, current treatment options are limited, and tumor recurrence occurs at a high rate due to treatment resistance. Aptamers, short single-stranded oligonucleotide ligands with high-affinity binding to molecular targets, are well suited tools for exploring novel targets in highly heterogeneous tumors with complex etiologies like GBM, where clinically relevant biomarkers are limited. In this study, aptamer-based cancer-specific drug target identification was performed by Adaptive Dynamic Artificial Polyligand Targeting (ADAPT) Biotargeting System. In short, a GBM-specific library was enriched through a Systematic Evolution of Ligands by EXponential enrichment (SELEX) process using micro dissected Formalin-Fixed Paraffin-Embedded (FFPE) tissues from GBM patients, along with whole body normal tissue for counterselection. Microdissection of tissue allows the partitioning of different types of cells to focus on specific cells of interest. The enriched libraries have been evaluated on clinical GBM and normal brain control samples through aptamer mediated tissue staining, resulting in preferential binding of enriched libraries compared to controls in the vast majority of GBM patients with little binding to normal brain samples. The final library was subsequently applied in an in-house developed library-based affinity pull-down assay using lysates from FFPE tissue of the same group of GBM patients and normal brain samples, followed by unbiased Mass Spectrometry for protein target identification. Combining the results from this proteomics analysis and data from the internal Whole Transcriptome Sequencing (WTS) database, we were able to identify several targets that are highly expressed in GBM and other cancer lineages. Antibody staining provided further validation of the expression levels and the cellular localization. The targets identified in this study include not only potential novel therapeutic targets, but also well-studied biomarkers and targets with available drugs already in clinical trials, demonstrating the platform has great potential for identifying high affinity binding and selectivity compared to traditional proteomics and other methods in drug target discovery. Citation Format: Xixi Wei, Myunggi An, Radhika Santhanam, Barbara Richardson, Lucas Vu, Justin Saul, Anna Walton, Michael Gee, Daniel Martin, Amanda Hubbard, Alexis Rodin, Matthew Rosenow, Tassilo Hornung. Identification of novel drug targets using the ADAPT biotargeting system on FFPE tissue from patients with glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB432.

Epidemiological assessment of hepatitis E virus infection among 1565 pregnant women in Siem Reap, Cambodia using an in-house double antigen sandwich ELISA.

This study investigated hepatitis E virus (HEV) prevalence among pregnant women in Siem Reap, Cambodia, by developing a cost-effective, user-friendly in-house enzyme-linked immunosorbent assay (ELISA) for detecting total anti-HEV immunoglobulins (Ig). The in-house ELISA was designed for large-scale screening in resource-limited settings. Its performance was benchmarked against two commercial tests: the Anti-HEV IgG EIA (Institute of Immunology, Co. Ltd) and the Anti-HEV IgG RecomLine LIA (Mikrogen). The in-house ELISA demonstrated a sensitivity of 76% and 71.4%, and a specificity of 94.1% and 98.6%, against the two commercial tests, respectively, with overall agreement rates of 92.4% and 94.3%. Among 1565 tested pregnant women, 11.6% were anti-HEV positive. Prevalence increased with age, particularly in women aged 35-40years and over 40years. No significant associations were found with education, number of children, family size, or history of blood transfusion and surgery, except for the occupation of the family head as a public officer. Of the total anti-HEV positive women, 22.7% had anti-HEV IgM, indicating recent or ongoing infection. The study concluded that the in-house ELISA is a viable option for HEV screening in regions with limited resources due to its high accuracy and cost-effectiveness. It is particularly suitable for large-scale studies and public health interventions in areas where HEV is endemic and poses a significant risk to pregnant women.

Treating amyotrophic lateral sclerosis with allogeneic Schwann cell-derived exosomal vesicles: a case report.

Schwann cells are essential for the maintenance and function of motor neurons, axonal networks, and the neuromuscular junction. In amyotrophic lateral sclerosis, where motor neuron function is progressively lost, Schwann cell function may also be impaired. Recently, important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been reported. This case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles, marking, to our knowledge, the first instance of such treatment. An 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral sclerosis. After initial diagnosis, the patient underwent a combination of generic riluzole, sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis, and taurursodiol. The patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron function. We confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired (senescent) and that exposure of the patient's Schwann cells to allogeneic Schwann cell-derived exosomal vesicles, cultured expanded from a cadaver donor improved their growth capacity in vitro. After a period of observation lasting 10 weeks, during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored, the patient received weekly consecutive infusions of 1.54 × 10 12 (×2), and then consecutive infusions of 7.5 × 10 12 (×6) allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco's phosphate-buffered saline. None of the infusions were associated with adverse events such as infusion reactions (allergic or otherwise) or changes in vital signs. Clinical lab serum neurofilament and cytokine levels measured prior to each infusion varied somewhat without a clear trend. A more sensitive in-house assay suggested possible inflammasome activation during the disease course. A trend for clinical stabilization was observed during the infusion period. Our study provides a novel approach to address impaired Schwann cells and possibly motor neuron function in patients with amyotrophic lateral sclerosis using allogeneic Schwann cell-derived exosomal vesicles. Initial findings suggest that this approach is safe.

Prevalence of Powassan Virus Seropositivity Among People with History of Lyme Disease and Non-Lyme Community Controls in the Northeastern United States.

Introduction: Lyme disease (LD) affects ∼476,000 people each year in the United States. Symptoms are variable and include rash and flu-like symptoms. Reasons for the wide variation in disease outcomes are unknown. Powassan virus (POWV) is a tick-borne flavivirus that causes disease ranging from asymptomatic infection to encephalitis, neurologic damage, and death. POWV and LD geographic case distributions overlap, with Ixodes species ticks as the common vectors. Clinical ramifications of coinfection or sequential infection are unknown. Objectives: This study's primary objective was to determine the prevalence of POWV-reactive antibodies in sera samples collected from previously studied cohorts of individuals with self-reported LD history residing in the Northeastern United States. As a secondary objective, we studied clinical differences between people with self-reported LD history and low versus high POWV antibody levels. Methods: We used an enzyme-linked immunosorbent assay (ELISA) to quantify IgG directed at the POWV envelope (E) protein domain III in 538 samples from individuals with self-reported LD history and 16 community controls. The samples were also tested with an ELISA assay to quantify IgG directed at the POWV NS1 protein. Results: The percentage of individuals with LD history and possible evidence of POWV exposure varied depending on the assay utilized. We found no significant difference in clinical symptoms between those with low or high POWV IgG levels in the in-house assay. Congruence of the EDIII and NS1 assays was low with only 12% of those positive in the in-house EDIII ELISA testing positive in the POWV NS1 ELISA. Conclusions: The results highlight the difficulty in flavivirus diagnostic testing, particularly in the retrospective detection of flavivirus exposure. The findings suggest that a prospective study with symptomatic patients using approved clinical testing is necessary to address the incidence and clinical implications of LD and POWV co-infection or sequential infection.

Longitudinal analysis of 20Years of external quality assurance schemes for PCR/NAAT-based bacterial genome detection in diagnostic testing.

Quality control (QC), quality assurance, and standardization are crucial for modern diagnostic testing in the field of medical microbiology. The need for efficient QC to ensure accurate laboratory results, treatment, and infection prevention has led to significant efforts in standardizing assay reagents and workflows. External quality assessment (EQA) schemes, like those offered by INSTAND, play a vital role in evaluating in-house and commercial routine diagnostic assays, regarded as mandatory by national and global guidelines. The recent impact of polymerase chain reaction/nucleic acid amplification technology (PCR/NAAT) assays in medical microbiology requires that high-performing assays be distinguished from inadequately performing ones, especially those made by inexperienced suppliers. The study assesses the evolving diagnostic performance trends over 2decades for the detection of EHEC/STEC, Borrelia (B.) burgdorferi, and MRSA/cMRSA. It explores the historical context of assay utilization, participant engagement, and rates of correct results in EQA schemes. The research seeks to identify patterns in assay preferences, participant proficiency, and the challenges encountered in detecting emerging variants or clinical strains. The study highlights the decline in in-house PCR assay usage, the emergence of new diagnostic challenges, and educational aspects within EQA schemes. Specific examples, such as the inclusion, in certain EQA surveys, of EHEC strains carrying stx-2f or B. miyamotoi, highlight the role of EQAs in increasing awareness and diagnostic capabilities. Advancements in MRSA detection, especially through the adoption of commercial assays, demonstrate the impact that technology evolution has had on diagnostic performance. Achieving excellence in diagnostic molecular microbiology involves a multifaceted approach, including well-evaluated assays, careful instrumentation selection, and structured training programs. EQA schemes contribute significantly to this pursuit by providing insights into the evolving diagnostic landscape and identifying areas for improvement in the diagnostic workflow as well as in PCR/NAAT assay design.

Detection of circulatory E. granulosus-derived cell-free DNA in the plasma and urine of human cystic echinococcosis using an in-house PCR: a potential promising diagnostic biomarker.

The diagnostic tool for identifying cystic echinococcosis (CE) patients at an early stage is currently lacking. However, circulatory cell-free DNA (cfDNA) has shown potential as a biomarker for parasitic infections and could be used for diagnosing CE. The plasma and urine samples were collected from 39 patients with confirmed CE through imaging and histopathological techniques. All plasma samples were tested for anti-echinococcal antibodies using a commercial ELISA test. Total plasma and urine cfDNA were extracted and an in-house PCR assay was developed to detect E. granulosus specific cfDNA in the samples of CE patients. Out of the 39 patients, 30 tested positive for E. granulosus using serology, with a sensitivity of 76.9%. Moreover, the detection rates for the cfDNA were 79.5% in plasma samples and 58.97% in urine samples using the 80bp COX1 gene. The plasma-based PCR and serology test showed the highest agreement (Kappa = 0.53). Plasma-based PCR has been found to be a reliable diagnostic tool for identifying CE patients at different cyst stages. It offers validity, speed, and sufficient sensitivity, making it an alternative to serology in diagnosing CE in endemic areas.

Screening Peptide Drug Candidates To Neutralize Whole Viral Agents: A Case Study with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

The COVID-19 pandemic revealed the need for therapeutic and pharmaceutical molecule development in a short time with different approaches. Although boosting immunological memory by vaccination was the quickest and robust strategy, still medication is required for the immediate treatment of a patient. A popular approach is the mining of new therapeutic molecules. Peptide-based drug candidates are also becoming a popular avenue. To target whole pathogenic viral agents, peptide libraries can be employed. With this motivation, we have used the 12mer M13 phage display library for selecting SARS-CoV-2 targeting peptides as potential neutralizing molecules to prevent viral infections. Panning was applied with four iterative cycles to select SARS-CoV-2 targeting phage particles displaying 12-amino acid-long peptides. Randomly selected peptide sequences were synthesized by a solid-state peptide synthesis method. Later, selected peptides were analyzed by the quartz crystal microbalance method to characterize their molecular interaction with SARS-CoV-2's S protein. Finally, the neutralization activity of the selected peptides was probed with an in-house enzyme-linked immunosorbent assay. The results showed that scpep3, scpep8, and scpep10 peptides have both binding and neutralizing capacity for S1 protein as a candidate for therapeutic molecule. The results of this study have a translational potential with future in vivo and human studies.