Paired Blood Samples Research Articles

Abstract 4575: mRNA expression in paired saliva and blood samples from different cancer indices

Abstract Introduction: Liquid biopsies have become gradually accepted, as a non-invasive alternative to traditional tumor biopsies in the field of oncology. The FDA and other regulatory bodies have already approved blood-based tests and researchers are working on validating urine, saliva and buccal swabs as alternative sample sources. This study’s main goal was to compare mRNA expression levels, in matched blood and saliva samples from cancer patients, as well as apparently healthy individuals. Methods: We collected matched saliva and blood samples from 35 individuals, including 27 patients diagnosed with cancers including Breast (4), Lung (4), Colon (5), Melanoma (3), Pancreatic (4), Prostate (7) cancer along with 9 healthy participants. The samples were collected in Wren’s proprietary buffer kit and RNA was extracted via TRIzol-based method. RNA sequencing was carried out on an Illumina Novaseq 6000. The data was analyzed using high performance computing (HPC) through PartekFlow software with the BWA aligner (hg38). Results: Nearly 94% of the genes found in saliva and 60% of the genes in blood were matched across all cancer types, with the exception of pancreatic cancer in blood, which showed only about 30% matching. We further evaluated both groups based on housekeeping genes (1003 genes) and the known cancer-associated genes as listed in the OncoKB database (1154 genes) for each cancer type. In addition, we investigated the expressions of 412 and 241 cancer genes priorly validated and used in IVD assays, respectively, in our lab. We found that 78-80% of the genes in blood were common across all cancer types, while saliva samples showed 64-73% commonality. Only 43% of genes detected in saliva from pancreatic cancer matched other cancer types. Out of the 241 internally validated cancer genes 68-71% genes were detected in blood and 57-65% in saliva in this cohort except pancreatic cancer where only 30% was detected. Out of the 412 genes, we found 67-69% in blood and 51-58% in saliva, again with the exception of pancreatic cancer, exhibits only 26% of genes. Additionally, 98% of housekeeping genes from blood and 71-87% of housekeeping genes from saliva were consistent, except for pancreatic cancer, which showed only 35%. Conclusion: Our study indicates that the majority of mRNA (94%) detected in saliva from various cancer types was also detected in blood, compared to healthy controls. This suggests that exploring mRNA-based biomarkers development in saliva could be even a more convenient alternative to blood. Citation Format: Srinivas V. Koduru, Mark Kidd, Abdel Halim. mRNA expression in paired saliva and blood samples from different cancer indices [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4575.

Clinical and dynamic circulating cytokines profile features of long-term progression-free survival benefit to immune checkpoint inhibitors in advanced non–small cell lung cancer

BackgroundImmune checkpoint inhibitors (ICIs) offer durable progression-free survival (PFS) benefit in a subset of patients with advanced non-small cell lung cancer (NSCLC). However, the predictors of long-term PFS (LTPFS) remain unclear.MethodsAdvanced NSCLC patients receiving first-line ICIs monotherapy at Guangdong Lung Cancer Institute between December 2017 and August 2022 were identified. Predictive value of different characteristics was evaluated in LTPFS (PFS ≥ 24 months) compared with short-term PFS (STPFS, PFS ≤ 3 months). Circulating cytokine levels were evaluated in paired peripheral blood samples collected before and after ICIs treatment.ResultsAmong 202 patients identified and 171 included (median follow-up: 41.0 months), 44 (25.7%) experienced LTPFS, associated with a 5-year overall survival (OS) rate of 81.2%. Squamous NSCLC, intermediate or poor lung immune prognostic index (LIPI) score, and liver metastases, were negatively associated with LTPFS. High tumor mutational burden (TMB, ≥ 10 mutations/megabase) was enriched in LTPFS compared to STPFS (P = 0.002). Patients with both high TMB and PD-L1 demonstrated the greatest survival benefit from first-line ICIs monotherapy (median PFS: 24.5 months, median OS: 67.0 months). Thirty-eight peripheral blood samples were collected before and after ICIs treatment from 10 patients with LTPFS and 9 with STPFS, which revealed increased CCL11 (P = 0.013) and decreased IL1RA (P = 0.001) and IL17A (P = 0.003) levels in LTPFS after ICIs treatment.ConclusionDistinct clinical characteristics, including TMB, PD-L1, pathologic subtypes, LIPI score, number of organs involved, metastatic sites, and dynamic circulating cytokines profile features, can distinguish NSCLC patients achieving LTPFS from those with STPFS following first-line ICIs monotherapy.

Beyond the blood-brain barrier: feasibility and technical validation of dual-compartment circulating tumor cells detection in high-grade glioma patients

The elusive nature of brain tumor progression, hidden behind the blood-brain barrier, presents significant challenges for treatment monitoring in high-grade gliomas. In this feasibility study, we evaluate a novel approach to tracking glioblastoma through liquid biopsy, assessing whether tumor cells leave detectable molecular footprints in both blood and cerebrospinal fluid (CSF). Using the MiSelect R II System with specialized microfluidic technology, we analyzed paired blood and CSF samples from six glioblastoma patients, revealing a striking presence of circulating tumor cells (CTCs)– with higher abundance in CSF, where detection rates reached 100% compared to 83.3% in blood. Our technical validation demonstrates the system’s capability to identify CTCs through multi-marker analysis (EGFR+/GFAP+/CD45-). Preliminary observations revealed higher CTC counts in CSF (median 15.5 cells/mL) compared to blood (median 3.0 cells/mL), with notable differences between compartments suggesting they may reflect distinct aspects of disease biology. In a patient who developed progressive disease, we observed a substantial increase in CSF CTCs from 14 to 116 cells/mL, warranting further investigation in larger cohorts. Additionally, we detected CTC clusters in both compartments, an intriguing finding with potential biological significance. While our interim analysis provides technical proof-of-concept for CTC detection in glioblastoma patients, the limited sample size precludes definitive conclusions regarding clinical utility. These findings establish a methodological foundation for future comprehensive studies exploring the relationship between CTC dynamics and clinical outcomes in high-grade gliomas.

Retinoblastoma: Molecular Evaluation of Tumor Samples, Aqueous Humor, and Peripheral Blood Using a Next-Generation Sequence Panel

Retinoblastoma was one of the first malignant tumors to be described as a genetic disease and its development occurs from the loss of function of the retinoblastoma gene (RB1). The difficulty in accessing the tumor during diagnosis highlights the need for non-invasive diagnostic methods. Studies have shown that liquid biopsy, obtained from any fluid material in the body, for example blood, contains free tumor cells and free and circulating DNA or RNA, making it a convenient tool for diagnosis and prognosis during cancer treatment without the need for invasive procedures. Taking advantage of these events, given this situation, we investigated molecular alterations in samples from retinoblastoma cases, using the NGS strategy as a powerful tool for characterization and aid in diagnosis and prognosis. Genomic data from 76 patients diagnosed with retinoblastoma, comprising 162 samples, tumor (TU), aqueous humor (AH), and peripheral blood (PB), were analyzed using the Oncomine Childhood Cancer Research Panel (OCCRA®). A total of 22 altered genes were detected, and 54 variants. Of the 76 cases, 29 included paired tumor (TU), aqueous humor (AH), and peripheral blood (PB) samples from the same patient. Alterations in the RB1 gene were detected in 16 of these 29 cases, with concordant alterations identified across all three sample types in three patients. In 12 out of 29 patients, the same genetic alteration was found in both TU and AH. In conclusion, the OCCRA panel enabled the detection, in different samples, of molecular alterations in the RB1 gene, as well as CNAs in the MYCN, ABL2, and MDM4 genes. Limitations of AH were observed, primarily due to the small volume of material available and the consequently low concentration of cell-free DNA (cfDNA). However, as AH provides a viable alternative for analyzing tumors, inaccessible to traditional biopsy methods, liquid biopsy holds significant potential to improve diagnostic accuracy and guide treatment strategies in retinoblastoma cases.

Occupational exposure to wildland firefighting and its effects on systemic DNA damage.

Occupational exposure to wildland firefighting and its effects on systemic DNA damage.

A Cross-Sectional Pilot Analysis of Downregulated Circulating MicroRNAs in Laryngeal Cancer

Background and Objectives: Despite notable advances in diagnosing and managing laryngeal cancer, the disease continues to present challenges, particularly in the advanced stages. Circulating microRNAs (miRNAs) are increasingly recognized as accessible biomarkers for cancer detection and follow-up. This exploratory study centers on identifying and evaluating miRNAs that are specifically downregulated in laryngeal carcinoma patients, aiming to clarify their clinical relevance in distinguishing pre- and post-therapeutic states. Methods: A total of 30 patients with laryngeal cancer provided paired blood samples before and after undergoing surgical or non-surgical treatment. To reduce variability and resource demand, each set of 10 samples was pooled into three pre-treatment groups (P1, P2, and P3) and three corresponding post-treatment groups (C1, C2, and C3). Total RNA, including miRNAs, was isolated from both plasma and exosomes, followed by qPCR-based profiling (Qiagen platform). Downregulated miRNAs were singled out through statistical comparisons using Mann–Whitney U tests; receiver operating characteristic (ROC) analyses and logistic regression were further applied to assess diagnostic utility. Results: Seven miRNAs demonstrated significant downregulation in the pre-treatment samples (fold changes ranging from 0.20 to 0.64, p < 0.05). Notably, hsa-miR-107 and hsa-let-7a-5p both showed marked reductions of approximately fivefold (p < 0.01), suggesting a strong association with active tumor presence. In ROC analysis, hsa-miR-107 achieved an area under the curve (AUC) of 0.78 (95% CI: 0.62–0.90) with 72% sensitivity and 74% specificity in differentiating pre- from post-treatment states. A logistic regression model incorporating downregulated candidates produced odds ratios between 0.52 and 0.64 (p < 0.05), pointing to their potential additive value in clinical decision-making. Conclusions: These preliminary findings indicate that certain miRNAs, when suppressed in circulation, may be linked to the oncogenic milieu of laryngeal cancer. Confirming these observations in larger, multicenter investigations is critical, but this pilot work underscores the promise of downregulated miRNAs as biomarkers of disease activity and potential guides to therapy response.

A Pilot Study on the Analysis of Circulating miRNA Upregulation in Laryngeal Cancer

Background and Objectives: Laryngeal cancer poses a significant clinical challenge, with late-stage diagnosis contributing to high morbidity and mortality. Circulating microRNAs (miRNAs) represent promising, minimally invasive biomarkers for earlier detection and improved therapeutic monitoring. This pilot study focused exclusively on miRNAs found to be upregulated in laryngeal carcinoma patients, aiming to elucidate their diagnostic and prognostic relevance. Methods: A total of 50 participants meeting standardized inclusion criteria were recruited from the ENT Clinic in Timișoara. Of these, 30 patients provided paired blood samples before and after treatment (surgical or non-surgical). Samples were pooled into three preoperative groups (P1, P2, P3) and three corresponding postoperative groups (C1, C2, C3). miRNAs were extracted from plasma and exosomes, and relative expression was measured by qPCR (Qiagen platform). Statistical analyses included Mann–Whitney U tests, receiver operating characteristic (ROC) curves, and logistic regression. Results: Seven miRNAs consistently exhibited significant upregulation preoperatively. Notably, hsa-miR-424-5p displayed a mean fold change of 4.59 (p = 0.0091) relative to postoperative samples, while hsa-miR-186-5p increased by 2.19-fold (p = 0.0030). hsa-miR-15b-5p also showed a substantial preoperative upregulation of 1.77-fold (p = 0.0057). In ROC analyses, hsa-miR-424-5p yielded an area under the curve (AUC) of 0.82 (95% CI 0.70–0.94), with 78% sensitivity and 80% specificity in distinguishing preoperative from postoperative status. Logistic regression indicated that elevated levels of hsa-miR-424-5p (OR = 1.56, 95% CI 1.10–2.20) and hsa-miR-186-5p (OR = 1.32, 95% CI 1.02–1.68) significantly predicted the preoperative disease state. Conclusions: These data underscore the potential of upregulated circulating miRNAs to serve as biomarkers for active laryngeal cancer and to monitor treatment response. Although preliminary, the findings encourage further research with larger cohorts and additional endpoints. With thorough validation, upregulated miRNAs could be integrated into clinical workflows, enhancing diagnostic precision, risk stratification, and postoperative surveillance in laryngeal cancer.

Analysis of N,N-dimethyltryptamine (DMT) and its metabolites using LC-MS/MS for forensic purposes.

Ayahuasca contains N,N-dimethyltryptamine (DMT), the primary alkaloid responsible for its psychedelic effects. DMT oxidative deamination yields indole-3-acetic acid (IAA) as the predominant metabolite, while N-oxidation produces N,N-dimethyltryptamine-N-oxide (DMT-NO) as the second most abundant metabolite. An LC-MS/MS method was developed and validated to quantify DMT, IAA, and DMT-NO in human plasma, as well as DMT and DMT-NO in human urine. Protein precipitation using a 75:25 (v/v) acetonitrile:methanol yielded analyte recoveries ≥91% in both plasma and urine. Key parameters including matrix effects, linearity, bias, precision, stability, carryover, and dilution integrity met their respective acceptability criterion outlined by ANSI/ASB 036 recommendations. In plasma, the linear range was 0.5-500 ng/mL (DMT), 0.25-125 ng/mL (DMT-NO), and 240-6000 ng/mL (IAA), while the DMT and DMT-NO range in urine was 2.5-250 ng/mL. Bias was within ±17.5%, and precision was ≤6.4% in both plasma and urine. Analytes were free from exogenous/endogenous interferences, and carryover was negligible. Extracts were also stable in the autosampler compartment (4°C) for 48 hours. A proof-of-concept study was conducted using authentic paired peripheral blood and urine samples. Results showed higher concentrations of DMT and DMT-NO found in urine as compared to plasma, highlighting the rapid metabolism and clearance of DMT and its metabolites. This study proposes the utility of DMT and DMT-NO as direct and distinctive biomarkers for forensic determination of exogenous DMT consumption. While IAA is the predominant metabolite of DMT, IAA should not be relied upon as the sole biomarker due to its substantial endogenous presence in both plasma and urine.

LungGENIE: the lung gene-expression and network imputation engine

BackgroundFew cohorts have study populations large enough to conduct molecular analysis of ex vivo lung tissue for genomic analyses. Transcriptome imputation is a non-invasive alternative with many potential applications. We present a novel transcriptome-imputation method called the Lung Gene Expression and Network Imputation Engine (LungGENIE) that uses principal components from blood gene-expression levels in a linear regression model to predict lung tissue-specific gene-expression.MethodsWe use paired blood and lung RNA sequencing data from the Genotype-Tissue Expression (GTEx) project to train LungGENIE models. We replicate model performance in a unique dataset, where we generated RNA sequencing data from paired lung and blood samples available through the SUNY Upstate Biorepository (SUBR). We further demonstrate proof-of-concept application of LungGENIE models in an independent blood RNA sequencing data from the Genetic Epidemiology of COPD (COPDGene) study.ResultsWe show that LungGENIE prediction accuracies have higher correlation to measured lung tissue expression compared to existing cis-expression quantitative trait loci-based methods (median Pearson’s r = 0.25, IQR 0.19–0.32), with close to half of the reliably predicted transcripts being replicated in the testing dataset. Finally, we demonstrate significant correlation of differential expression results in chronic obstructive pulmonary disease (COPD) from imputed lung tissue gene-expression and differential expression results experimentally determined from lung tissue.ConclusionOur results demonstrate that LungGENIE provides complementary results to existing expression quantitative trait loci-based methods and outperforms direct blood to lung results across internal cross-validation, external replication, and proof-of-concept in an independent dataset. Taken together, we establish LungGENIE as a tool with many potential applications in the study of lung diseases.

Saliva Samples as a Potential Tool for the Diagnosis and Monitoring of Cytomegalovirus Reactivation in Children Undergoing Transplantation.

Saliva Samples as a Potential Tool for the Diagnosis and Monitoring of Cytomegalovirus Reactivation in Children Undergoing Transplantation.

Comparison of the capillary and venous blood plasma lipidomes: validation of self-collected blood for plasma lipidomics.

Comparison of the capillary and venous blood plasma lipidomes: validation of self-collected blood for plasma lipidomics.

Clinical and pathological risk factors for postencephalitic epilepsy after herpes simplex virus-1 encephalitis in children

The high rate of postencephalitic epilepsy (PE) contributes to the unfavorable clinical outcome of herpes simplex virus-1 encephalitis (HSE). We aimed to identify the risk factors and explore possible mechanisms of PE in childhood following HSE. We conducted a retrospective review of children diagnosed with HSE and patients were categorized into two groups based on the presence or absence of PE. Multivariate logistic regression analysis was used to analyze factors associated with PE. Furthermore, cytokine and albumin levels in paired cerebrospinal fluid (CSF) and blood samples during acute HSE were also retrospectively reviewed. 97 HSE patients were included in the study and PE was diagnosed in 46. On multivariate analysis, the features predictive of PE (presented as odds ratio [OR] with confidence intervals [CIs]) were status epilepticus (OR 9.38, CI 1.71–10.37), focal seizures (7.41, 1.42–16.97), and restricted diffusion on MRI (6.15, 1.16–20.31). The median QAlb value (CSF to serum albumin ratio, a marker of blood-brain-barrier [BBB] integrity), levels of interleukin (IL)-6 and IL-6:IL-10 ratio in CSF were higher in children with PE during acute HSE. However, CSF levels of IL-10 were higher in non-PE patients. Furthermore, greater CSF IL-6 levels were associated with higher QAlb. These results demonstrated that enhanced BBB impairment and exaggerated proinflammatory response may play a role in the pathogenesis of PE following HSE.

Association between clonal hematopoiesis and survival after nephrectomy in patients with renal cell carcinoma.

589 Background: Clonal hematopoiesis of indeterminate potential (CH) is an age-related phenomenon marked by the clonal expansion of hematopoietic stem cells harboring somatic mutations in the absence of hematologic transformation. These mutations have been linked to worse all-cause mortality from both oncologic and cardiovascular-related risk. Recent pan-cancer studies have also found that CH is common in patients treated for solid tumors and may be associated with survival. We thus sought to characterize CH mutations and their associated clinical impact in patients with localized renal cell carcinoma (RCC) at our institution. Methods: Utilizing a single institutional database of patients who underwent targeted, next-generation sequencing of paired tumor and blood samples (MSK-IMPACT), we identified 311 patients who were diagnosed with localized RCC and underwent nephrectomy. CH mutations were called using a two-tiered filtering schema, requiring a variant allele fraction (VAF) in blood greater than twice that of tumor. Chi-square and Wilcoxon rank-sum tests were used to compare clinical characteristics by CH status. Cox-proportional hazards modeling was used to test the association between CH and survival time following nephrectomy, adjusting for age and presence of diabetes, coronary artery disease (CAD), chronic kidney disease, hypertension, and smoking. We performed separate analyses for patients older and younger than the median age of 56.8 years as these groups had distinct CH, survival, and comorbidity profiles. Results: We assessed variants in 341 genes within the MSK-IMPACT CH database for 311 patients (CH: 79 [25.4%], no CH: 232 [74.6%]) who had localized RCC and underwent a nephrectomy (partial: 114 [36.7%], radical: 197 [63.3%]). DNMT3A (26), PPM1D (7), and TET2 (4) were the most common CH mutations. Patients with CH were older (median age of 64.1 years [IQR: 54.6 to 72.3] vs. 54.8 years [46.1 to 63.5]; p < 0.001) and had higher incidence of CAD (8/48 [16.7%] vs. 12/263 [4.7%], p = 0.004). There was no difference in rates of diabetes, hypertension, or CKD. For patients older than the median age of 57 years, those with CH had a shorter median survival of 86 months [72 to 119] compared to 125 months [96 to NR] (p = 0.02). For patients younger than the median age, age and hypertension were significantly associated with survival time but not CH (p = 0.29). Conclusions: Our study reveals that CH is common in localized RCC patients and may be associated with worse survival especially in older patients. Given the possibility of confounding from other comorbidities, future efforts will focus on identifying the true attributable effect of CH on survival. However, CH clones have been shown to interact with tumor cells and may influence immune surveillance, potentially providing a molecular basis for these findings.

Evaluation of SARS-CoV-2 Antibody Response Between Paired Fingerprick (HemaPEN®) and Venepuncture Collected Samples in Children and Adults.

Serological surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is important to monitor population COVID-19 immunity. Dried blood spots (DBS) are a valuable method for serosurveys, particularly in remote settings and in children. We compared the measurement of SARS-CoV-2 spike-specific IgG in paired blood samples collected using standard venepuncture (serum) and the hemaPEN® microsampling DBS device from children and adults. A total of 83 participants (10 months to 65 years of age), comprising COVID-positive and -negative participants, were recruited. Paired serum and DBS samples were assayed for SARS-CoV-2 receptor-binding domain (RBD) and Spike (S1) antibodies using an established in-house ELISA. RBD and S1 IgG concentrations of paired hemaPEN DBS eluates and serum samples were compared using a non-parametric Wilcoxon matched-pairs signed ranked test. A Pearson's correlation was used for RBD and S1 IgG concentrations and the level of agreement between the hemaPEN DBS eluates and serum samples was assessed by Bland-Altman analysis. A total of N = 41 adults (36 COVID-positive and 5 COVID-negative), and N = 42 children (37 COVID-positive, and 5 COVID-negative) have paired serum and DBS assayed. We found moderate to strong correlations between paired hemaPEN DBS eluates and serum SARS-CoV-2 IgG antibodies for RBD (r = 0.9472, p < 0.0001) and S1 proteins (r = 0.6892, p < 0.0001). Similar results were observed in both adult and paediatric populations. No significant differences in S1-specific IgG levels were observed in hemaPEN DBS samples stored for up to 35 weeks at room temperature. Eluted hemaPEN samples showed high specificity and sensitivity (100% and 89.89%, respectively) compared with serum. The use of the microsampling hemaPEN device for DBS sample collection is a feasible approach for assessing SARS-CoV-2 antibodies for serosurveillance studies, particularly in remote settings and in children.

Concordance of maternal and cord blood SARS-COV-2 immunoglobulin seropositivity after COVID-19 infection or vaccination in pregnancy.

To assess maternal antibody response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection during pregnancy and subsequent transplacental antibody transfer in cord blood. This is a prospective cohort study of Coronavirus Disease 2019 (COVID-19) polymerase chain reaction (PCR) positive pregnant women and their newborns. SARS-CoV-2 PCR (+) women were enrolled, with SARS-CoV-2 PCR (-) as control. Maternal blood was obtained at enrollment and cord blood collected at delivery. Baseline maternal and infant characteristics and neonatal outcomes were collected. Samples were analyzed using coronavirus antigen microarray containing immunologically significant antigens from SARS-CoV-2 (including nucleocapsid protein [NP], spike protein [S], S1, S2, receptor-binding domain [RBD]) which can detect SARS-CoV-2 immunoglobulin G (IgG) and immunoglobulin M (IgM). Thirty-seven maternal-cord blood paired samples were analyzed for SARS-CoV-2 IgG or IgM antibodies; 15 out of 20 samples from SARS-CoV-2 PCR (+) and 14 out of 17 from SARS-CoV-2 PCR (-) mothers were IgG positive. 14 out of the 17 SARS-CoV-2 PCR (-) mothers received COVID-19 vaccine during pregnancy. Difference between IgG seropositivity of naturally infected versus vaccinated mothers were significant, 75% versus 100% (p = 0.043). IgM antibodies were detected in 10 out of 20 SARS-CoV-2 PCR (+) women but none were detected in cord blood. Excellent concordance of SARS-CoV-2 IgG antibodies exist between maternal and cord blood. Significantly higher SARS-COV-2 cord blood IgG seropositivity was found in vaccinated versus naturally infected mothers.

Somatic variants in SLC35A2 leading to defects in N-glycosylation in mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE).

Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) is a new histopathological entity identified in the surgically resected brain tissue of patients with drug-resistant epilepsy. Somatic variants in SLC35A2 have been increasingly identified in MOGHE brain resections. SLC35A2 protein transports uridine 5'-diphosphogalactose (UDP-Gal) into the Golgi lumen, playing a crucial role in the process of N-glycosylation. Currently, research on the pathogenic mechanism of SLC35A2 variants in MOGHE is limited. Here we conducted genetic testing on brain samples and paired blood samples from 28 pediatric patients pathologically diagnosed with MOGHE. We performed an in-depth functional analysis of somatic variants identified in SLC35A2, integrating glycan labeling and intact glycopeptide profiling to assess N-glycosylation defects. With whole-exome sequencing and validation with ultra-deep amplicon sequencing, we identified 101 potentially pathogenic somatic variants (PPSVs) across 87 genes. Nine PPSVs in SLC35A2 were found in 10 samples. The 9 identified variants of SLC35A2, characterized by various mutation types (4 frameshift, 3 missense and 2 nonsense variants), were all confirmed to be loss-of-function via altered glycan chains. Intact glycopeptide analysis at the cellular level indicated an increase in truncated N-glycan glycoforms. Analysis of brain tissue revealed N-glycosylated proteins and glycosites modified with agalactosylated glycoforms, and glycoproteins bearing agalactosylated N-glycans were significantly enriched in cell adhesion and axon guidance-related pathways. Additionally, chemoenzymatic glycan labeling in lesions demonstrated N-glycan damage of heterotopic neurons, suggesting a potential diagnostic approach for MOGHE. Our findings provide a comprehensive somatic landscape of MOGHE and a rich resource of somatic SLC35A2 variant-related glycoform and glycoprotein abnormalities, thereby unveiling valuable insights into compromised N-glycosylation and MOGHE formation.

Identification of clonally expanded T-cell receptor sequences in giant cell arteritis.

Identification of clonally expanded T-cell receptor sequences in giant cell arteritis.

P-2316. Comparing Whole Blood and Plasma Samples to Monitor EBV and CMV after transplantation

Abstract Background Viral reactivation may occur after hematopoietic stem cell transplantation (HSCT) or solid organ transplantation owing to immunosuppression and can lead to severe consequences. Routine weekly monitoring using quantitative PCR is recommended for cytomegalovirus (CMV) after both allogeneic HSCT and solid organ transplantation and for Epstein–Barr virus (EBV) after allogeneic HSCT. However, the sample type most suitable for monitoring remains unclear. Methods This retrospective analysis included 54 patients who underwent weekly viral monitoring using whole blood samples after HSCT or liver transplantation at the Nagoya University Hospital, Japan from January to December 2021. Whole blood and plasma samples were compared for their respective EBV and CMV DNA loads in the weekly serial samples from patients who tested positive for EBV or CMV at least once during the weekly virus monitoring. Subsequently, the dynamics of viral DNA were analyzed between the two sample types. Results Based on whole blood samples, EBV DNA was detected in 22 patients, whereas CMV DNA was detected in 24 patients. Both EBV and CMV were detected in 13 patients. A total of 164 and 183 pairs of whole blood and plasma samples, respectively, were compared for EBV and CMV DNA. EBV DNA was detected more frequently in whole blood (55%) than in plasma (18%). The detection rate of CMV DNA was similar between the two sample types. The correlations between the viral loads in the two sample types were 0.515 and 0.688 for EBV and CMV, respectively. Among paired samples in which EBV DNA was detected in whole blood, the plasma EBV detection rate was significantly higher in patients who underwent hematopoietic stem cell transplantation than in those who underwent liver transplantation (42% vs. 19%, p = 0.022). After the week with the highest viral load in whole blood, subsequent trends in viral load exhibited similar patterns in both EBV and CMV DNA levels in both whole blood and plasma samples. Conclusion The EBV detection rate was higher in whole blood, and a high correlation was observed between CMV DNA loads in whole blood and plasma samples. These results indicate that whole blood is useful for monitoring both EBV and CMV, whereas plasma is a potential alternative sample for monitoring CMV. Disclosures All Authors: No reported disclosures

P-1988. COVID-19 vaccine induced antibodies in human milk: exploring form and function

Abstract Background Following SARS-CoV-2 vaccination/infection of pregnant/lactating women, human milk contains SARS-CoV-2 antibodies (Ab). Limited data exists on whether those Ab induce protection for infants against COVID-19. Among 45 lactating women who received primary and booster SARS-CoV-2 vaccines from 2021 to 2022, we previously showed that anti-receptor binding domain (RBD) IgG and IgA significantly increased in serum and milk following booster SARS-CoV-2 vaccine but did not differ by maternal nucleoprotein (NP) status. In this exploratory analysis, we aimed to further characterize the Ab present in human milk following maternal booster SARS-CoV-2 vaccination. SARS-CoV-2 Neutralization Antibodies in Human Milk by Maternal Nucleoprotein Status before and after SARS-CoV-2 Booster Vaccine. Neutralization titers in human milk significantly increased among women with hybrid immunity (NP+) after booster vaccine (P=0.04) but not for women with vaccine only immunity (NP-). Methods Using a subset of paired longitudinal milk and blood samples from a cohort of 45 lactating women who received primary and booster SARS-CoV-2 vaccines from 2021 to 2022, we characterized neutralizing Ab, RBD IgG subclasses (IgG1-IgG4), and Ab-dependent complement activation (ADCA). Antibody-Dependent Complement Activation (ADCA) using Human Milk from Lactating Women before and after SARS-CoV-2 Booster Vaccine. Two women with hybrid immunity (NP+) had significantly positive ADCA after SARS-CoV-2 booster vaccine, human milk from all others resulted in low or no activation of complement. Results For 7 NP+ (hybrid immune) and 7 NP- (vaccine immune) women, SARS-CoV-2 neutralization titers increased in serum and milk after booster vaccine among NP+ women (p=0.04) but not for NP- women (Fig1). After booster vaccine, ADCA was positive but variable in maternal serum and milk with only 2/12 (16%) women demonstrating high-levels of ADCA in human milk (Fig2). These same two women demonstrated different IgG subclass profiles in milk after booster vaccine with moderate to high levels of IgG1 and IgG3, and low levels of IgG4 (Fig3). This was inverse for all other women who demonstrated moderate to low levels of IgG1 and high titers of IgG4 in human milk. Notably, both women with high ADCA response were NP+ and vaccinated with primary SARS-CoV-2 vaccine more than 4 months post-partum, while all others received primary SARS-CoV-2 vaccine while pregnant or less than a month post-partum. IgG Subclasses in Human Milk before and after SARS-CoV-2 booster vaccine by Complement Activation Status Human milk with high complement activation demonstrated higher levels of IgG1 and IgG3 after booster vaccine compared to women with low complement activation. Conclusion The different Ab profile may indicate a tolerizing response that could be related to pregnancy at time of initial antigen exposure or from repeat SARS-CoV-2 vaccination and warrants future investigation (additional samples are under analysis). Nonetheless, human milk demonstrates robust binding and neutralizing Ab following SARS-CoV-2 vaccination, offering other potential mechanisms for protection of infants against COVID-19 infection. Disclosures Anne-Marie Rick, MD, MPH, PhD, Pfizer: Advisor/Consultant

P-235. Non-utility of Catheter Tip Cultures in the Diagnosis of Catheter-related Bloodstream Infections

Abstract Background Catheter-related bloodstream infections (CRBSIs) affect approximately 3 to 27% of patients. As per IDSA (2009) criteria, concordant organisms from blood and catheter tip cultures, or specific criteria met by two blood samples are required for CRBSI diagnosis. Catheter tip cultures necessitate removal of the line and entail increased healthcare costs. Emerging evidence questions the reliability of this labor-intensive practice in diagnosing CRBSI. We aimed to determine the utility of catheter tip cultures in diagnosing CRBSI at our Institute. Catheter tip culture and Blood culture results CRBSI: Catheter-related Bloodstream Infection; TC: Catheter tip culture; BC: Blood culture; + or - , growth or no growth Methods We conducted a prospective observational study in patients with suspected CRBSI. Catheter tips and paired blood samples collected within 48 hours, were sent for culture. CRBSI was diagnosed as per IDSA 2009 guidelines. The utility of catheter tip cultures in diagnosing CRBSI was calculated. Results One-hundred and thirty events of suspected CRBSI were included in 116 patients. Sixty-two percent of patients were male with a mean age of 43.75 ± 16.5 years. The prevalence of CRBSI was 16.9%, of which only 27% of CRBSI were identified by catheter tip cultures. The sensitivity, specificity, positive predictive value, and negative predictive value of catheter tip cultures in diagnosing CRBSI were 27.3% (10.7- 50.2), 77.8% (68.8-85.2), 20.0% (10.4- 35.0) and 84.0% (79.9-87.4) respectively. Catheter tip colonization was observed in 20.8% of catheter tip cultures. All repeat blood cultures sent in the following two weeks in patients with catheter-tip colonization, were sterile. Amongst patients with CRBSI, Multidrug-Resistant Acinetobacter baumanii and Klebsiella pneumoniae were the most frequently isolated organisms, followed by Candida spp (predominantly Candida auris), accounting for 27% of CRBSI cases. Conclusion Our study showed poor sensitivity and low positive predictive value of catheter tip cultures in diagnosing CRBSI. Employing catheter-sparing methods, such as evaluation of differential time to positivity and quantitative paired blood cultures, will improve the diagnosis of CRBSI, and can lower hospital expenses. Disclosures All Authors: No reported disclosures