Citations

Abstract Description Fungal species, such as Candida albicans, are commonly found as part of the normal microbiota in both the skin and intestine. However, these fungal species, including C. albicans, can also become opportunistic pathogens and have been associated with intestinal and allergic disorders. We hypothesized C. albicans colonization could occur in early life when the neonatal microbiota is permissive to pathogens and lacks colonization resistance compared to later times in life. To investigate this question, we sequenced stool of premature and term infants and frequently found C. albicans colonization, suggesting fungal colonization within the human GI tract. To investigate the impact of long-term C. albicans colonization to the immune system, we established colonization by oral administration of C. albicans to neonatal mice. Colonization of C. albicans was associated with increased diversity of bacterial species in the intestinal microbiota at weaning. Additionally, we observed significant increases of inflammatory cytokines IL-17 and G-CSF in the serum. Future research will expand on the impact of C. albicans colonization on the intestinal microbiota and immune systems. Funding Sources Center for Individualized Medicine Microbiome Program Research Team Science Award, Mayo Clinic NIH, NIDDK R01 DK134366 Topic Categories Mucosal and Regional Immunology (MUC)

Abstract Description Late-onset neonatal sepsis (LOS) is often the result of systemic bacteremia developing between 3-90 days of age, predominantly in prematurely born populations. An initial spike of IL-6 serum levels is a hallmark diagnostic tool and has been implicated as a source for the resulting cytokine storm. Yet, other than antibiotics, there is a lack of effective therapeutics targeting the overwhelming inflammatory response. We performed single-organism infections of pathogenic and commensal clinical E. coli isolates to compare the acute cytokine response in our LOS model in neonatal (postnatal day 5-7) and periweaning (postnatal day 17-20) pups. As expected, neonatal pups had increased bacterial burden and mortality during pathogenic infection compared to periweaning-age and commensal infection. An in-depth, 32-cytokine analysis of serum, liver, and spleen revealed overall elevated and tissue-specific inflammation in the neonates with a positive correlation of IL-6 serum levels to many cytokines (MCP-1, M-CSF, MIP-1β, etc.). Isolate-specific responses were assessed in an in vitro co-culture model with RAW-blue macrophages. While both isolates induced inflammatory NFκB/AP-1 activation, commensal E. coli caused elevated IL-1β while pathogenic E. coli led to significantly elevated IL-6. Both age- and pathogenic-specific inflammatory activation suggest unique signaling from the E. coli infection and the neonatal response, calling for neonatal-specific treatment options. Funding Sources Mayo Clinic Graduate School of Biomedical Sciences R01 DK134366 (Knoop) T32 DK124190-04 (Muske) Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Abstract Description Broad spectrum antibiotics are being increasingly used in obstetric patients without long term follow up on neonatal risks. Previous data have suggested antibiotics for preterm premature rupture of membranes increases neonatal late onset sepsis and nectrozing enterocolitis (NEC), but the mechanism is unknown. We analyzed samples from the Mechanisms of Maternal Immunoglobulin A control over the neonatal microbiota and the development of NEC (MAMI) trial. MAMI enrolled infants born under 32 weeks and collected maternal-infant biospecimens. We performed a detailed chart review for maternal antibiotic exposure and analyzed breast milk samples collected 10-45 days post delivery by ELISA. Data were compared by t test and one way ANOVA. Breast milk IgA was higher than IgG and IgM (p < 0.0001, p < 0.005). When compared by antibiotic exposure, IgA and IgM were decreased with any antibiotic exposure (p = 0.02, p = 0.01). IgA was decreased by length of antibiotic exposure (p = 0.02). We stratified by the antibiotic spectrum of activity into narrow (penicillin, ampicillin) and broad (2nd and 3rd generation cephalosporin, gentamicin, etc) and found that the spectrum of antimicrobial activity was associated with a decrease in maternal IgA with broad spectrum antibiotics with the least amount of IgA (p < 0.004). Our data demonstrate mammary IgA and IgM are decreased with antenatal antimicrobial exposure. These data suggest a mechanism by which antenatal antibiotics may lead to neonatal sepsis and NEC. Topic Categories Mucosal and Regional Immunology (MUC)

Abstract Description Neonatal sepsis caused by bacteria such as Escherichia coli affects 1.3 million infants a year. The immunological responses activated in neonates during neonatal sepsis are currently thought to overwhelm the infant. Understanding where to intervene in the inflammatory response could lead to the development of therapeutics. Using Nur77-GFP reporter mice and our established animal models of neonatal sepsis, we observed γδ T cells-innate-like lymphocytes- are activated in a TCR-dependent manner in response to pathogenic bloodstream E. coli infection in neonatal mice (post-natal day 5-7). We find a subset of γδ T cells show similar levels of TCR-dependent activation of following infection with either pathogenic or commensal E. coli. In pathogenic bloodstream E. coli infection, there is a significant release of pro-inflammatory cytokines IL-17 by these CCR6+ γδ T cells in addition to IL-6 in the serum compared to serum in commensal infection. We found that in neonatal mice, CCR6+ γδ T cells have high expression of IL-6 receptor, and preliminary data suggests IL-6 blockade reduces IL-17 production. In summary, this suggests that during an E. coli systemic infection, the IL-17 producing γδ T cells are being activated by IL-6 due to higher levels of IL-6 receptor. Further work will seek to understand how γδ T cells may detrimentally contribute to neonatal sepsis outcomes. Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)

Abstract Description Infants are vulnerable to infectious diseases due to the immaturity of their immune system, including a delay in producing pathogen-targeting antibodies. Maternal immunization strategies have increased in use to protect infants from disease by vertical transfer of protective pathogen-specific antibodies. Late-onset sepsis (LOS) is a substantial contributor to neonatal mortality that results from a bloodstream infection at least 72 hours after birth. The implicated pathogen is often a member of the intestinal microbiome before systemic infection, suggesting translocation from the intestine as the path to the bloodstream. We hypothesized that maternal immunization of animals prior to pregnancy could protect nursing pups in a murine model of LOS. Following maternal immunization against Enterobacteriaceae taxa implicated in sepsis, we observed significantly decreased pup mortality following an oral challenge with Escherichia coli. This protection was associated with increases in antigen-specific IgG and IgA in both the mammary tissue of vaccinated dams and stomach contents of nursing pups. Interestingly, we did not observe differences in the infant microbiota following maternal vaccination, suggesting increased pathogen-specific IgG and IgA did not perturb the developing microbiota. This work suggests maternal immunization may be useful to protect offspring from enteric pathogens, and further supports the role of human milk and human milk factors in protection from LOS. Funding Sources Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (CARB-X) Topic Categories Vaccines and Immunotherapy (VAC)

Background: Qualification of non-invasive tests (NITs) and blood biomarkers for fibrosis severity and risk assessment is an unmet need in clinical care for cirrhosis. The paucity of reproducibility data for imaging and blood biomarkers in cirrhosis hinders their application for longitudinal monitoring. The aim of this study was to evaluate the reproducibility of imaging and blood biomarkers in a prospective cohort of adults with cirrhosis. Methods: We prospectively enrolled adults with cirrhosis in an observational, longitudinal cohort study. Participants completed a research visit with vibration-controlled transient elastography (VCTE) with liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) and blood testing, including AST, ALT, platelets, alpha-fetoprotein (AFP), and the Fibrosis-4 Index (FIB-4). Biomarkers were repeated a median of 3 months apart without any interim intervention. The primary outcome was the reproducibility of each biomarker as assessed by the reproducibility coefficient (RDC%), within-participant coefficient of variation (wCV), intraclass correlation coefficient (ICC), and Bland–Altman analysis. Results: In total, 40 participants (mean age 62, 60% female, mean BMI 28.6 kg/m 2 ) had VCTE/CAP, 38 AST/ALT, and 26 had AFP at both time points. The RDC% for VCTE-LSM was 54.4, wCV 0.19, and ICC 0.91. VCTE CAP had an RDC% of 56, a wCV of 0.30, and ICC 0.47. AFP had an RDC% of 58, a wCV of 0.21, and an ICC of 0.95. RDC% for AST, ALT, and FIB-4 ranged from 70% to 79%. On Bland–Altman analyses, VCTE-LSM demonstrated the lowest relative bias (0.4%). Conclusions: Prospective assessment of repeat biomarkers in adults with cirrhosis found that VCTE-LSM and CAP provide consistent assessments across individuals but may yield substantial within-individual variation. Blood-based biomarkers had poor reproducibility within individuals but were consistent in detecting between-patient variability. These data can inform ultrasound-based non-invasive testing qualification by defining thresholds that may reflect measurement variability rather than true biologic change over time.

ABSTRACT Background Chronic myelomonocytic leukemia (CMML) is largely a disease of individuals older than 50 years; its occurrence in patients aged 50 years and younger is rare. The authors sought to characterize the clinicopathologic features and genetic profile of young‐onset (age 50 years and younger) CMML (y‐CMML) compared with older onset (older than 50 years) CMML (o‐CMML). Methods The authors conducted a multi‐institutional study of 32 patients with y‐CMML and 119 patients with o‐CMML, analyzing clinical, morphologic, cytogenetic, and molecular data. Results Patients who had y‐CMML frequently presented with splenomegaly (59% vs. 11%; p < .001) and hepatomegaly (25% vs. 2%; p < .001) compared with those who had o‐CMML. Although the overall incidence of cytogenetic abnormalities was similar, patients who had y‐CMML exhibited distinct mutational patterns. PTPN11 mutations were significantly more common in y‐CMML (13% vs. 3%; p = .034) than in o‐CMML, whereas TET2 (6% vs. 57%; p < .001) and SRSF2 (16% vs. 46%; p = .002) mutations were significantly less frequent. In addition, multi‐hit TET2 (6% vs. 34%; p = .002) and TET2‐SRSF2 (3% vs. 29%; p = .003) co‐mutations were rare in y‐CMML. However, the molecular differences did not affect the CMML‐specific risk‐stratification categories because the clinical outcomes, including overall survival and leukemia‐free survival, did not differ between the two groups. Conclusions CMML in patients aged 50 years and younger is rare and presents with unique clinical and mutational features, suggesting a distinct pathogenesis.

Abstract BACKGROUND Understanding long-term sequelae of cancer care is critical. Cognitive impairment is a common and disabling survivorship issue. Because sex influences tumor biology, therapy exposure, and dementia risk, we examined whether cancer care for a prior malignancy alters late-life cognitive outcomes differently in males and females. METHODS We assessed adults ≥50 years, cognitively normal at study entry, from a longitudinal, population-based cohort (Mayo Clinic Study of Aging). Participants were linked to our institutional cancer registry (excluding non-melanoma skin cancers). Mild cognitive impairment (MCI) and dementia were adjudicated by consensus. We fitted multivariable Cox proportional-hazards models to estimate how prevalent cancer diagnosis influenced the risk of developing MCI/dementia. Sex-specific effects were determined by incorporating a cancer×sex interaction term and by generating separate hazard ratios. Analyses were controlled for age, APOE4 status, education, and presence of vascular/metabolic conditions. RESULTS 5793 MCSA participants (female: 49.4%, APOE4 positive: 27.5%) were included in the study, with a mean age of 73 years at study entry. Incident MCI was recorded in 866 participants, and 737 were diagnosed with incident dementia. About 20% (n=1176) of the cohort had a cancer diagnosis, most commonly prostate (n=423) and breast (n=277). There was no independent relationship between history of cancer and risk for MCI or dementia. We found that males with cancer had an increased risk for MCI (HR 1.28, 95% CI 1.04-1.57, p=0.003) and dementia (HR 1.29, 95% CI 1.04-1.6, p=0.053). Conversely, females with cancer had a lower risk for MCI (HR 0.79, 95% CI 0.61-1.01, p=0.063), although this was not statistically significant. CONCLUSIONS Our data suggests male cancer survivors may be more susceptible to cognitive impairment, independent of age, APOE4 status, education, and vascular/metabolic burden. Elucidating the hormonal, treatment-related, and systemic pathways driving this should be a priority for future mechanistic studies.

Abstract BACKGROUND Mirdametinib is the first FDA-approved MEK1/2 inhibitor for both adults and children ≥2 years with NF1 who have symptomatic PN not amenable to complete resection. We report results from the phase 2b ReNeu trial (NCT03962543), including the LTFU. METHODS In ReNeu, mirdametinib was administered in 3-weeks-on/1-week-off 28-day cycles. Following the 24-cycle treatment phase, patients could continue mirdametinib in an optional LTFU. We report results through June 12, 2024, approximately 9 months from the previous data cutoff. RESULTS Fifty-eight adults and 56 children received mirdametinib. Median (range) duration of treatment was 21.8 (0.4, 54.4) months in adults and 25.4 (1.6, 48.5) months in children. Among LTFU-eligible patients, 26/31 (84%) adults and 32/37 (86%) children entered LTFU. Confirmed objective response rate (ORR, treatment+LTFU phases) was 47% (27/58; 95%CI, 33%, 60%) in adults and 55% (31/56; 95%CI, 42%, 69%) in children. Among confirmed responders, 18 adults and 19 children achieved a deep response (best target PN volume reduction from baseline of &gt;50%). Median (range) best percentage change from baseline in target PN volume was –41% (–90%, 13%) in adults and –43% (–98%, 48%) in children. Median duration of response (DoR) was not reached for either age cohort. Treatment-related adverse events (TRAEs) in ≥25% of patients were dermatitis acneiform, diarrhea, nausea, and vomiting in adults; and diarrhea, dermatitis acneiform, and paronychia in children. Grade ≥3 TRAEs occurred in 17% of adults and 25% of children. Dose interruptions, dose reductions, and discontinuations due to TRAEs occurred in 9%, 17%, and 22%, respectively, of adults, and 14%, 14%, and 9%, respectively, of children. CONCLUSIONS Improved confirmed ORR was observed with longer duration of mirdametinib, with additional deep responses achieved in both adults and children. Mirdametinib continued to be well tolerated with a manageable safety profile and no new safety signals in the LTFU.

Abstract BACKGROUND Mirdametinib is the first FDA-approved MEK1/2 inhibitor for both adults and children (≥2y) with symptomatic NF1-PN. In ReNeu, symptomatic improvement and PN volume reductions were observed at the earliest assessments (~91 and ~152 days, respectively) and were sustained. This analysis evaluated time to first onset and resolution of commonly reported TRAEs in the ReNeu trial. METHODS Data cutoff (DCO) was September 20, 2023. Median time to first onset and resolution (days) for common TRAEs (≥15%) were evaluated for prepubescents (≥2 to &lt;12y, n=32), postpubescents (≥12 to &lt;18y, n=24), younger adults (≥18 to ≤50y, n=48), and older adults (&gt;50y, n=10). RESULTS Common TRAEs were mostly grades 1 to 2 (83%). In prepubescents, median day (range) of onset was 32 (14, 263) for vomiting, 71 (19, 386) for dermatitis acneiform, 123 (1, 663) for diarrhea, 124 (52, 775) for paronychia, and 127 (2, 663) for nausea. For postpubescents, median day (range) of onset was 8 (1, 438) for diarrhea, 8 (2, 574) for nausea, 12 (1, 252) for dermatitis acneiform, 28 (2, 354) for vomiting, and 110 (43, 245) for paronychia. In younger adults, median day (range) of onset was 5 (1, 352) for nausea, 8 (2, 15) for dermatitis acneiform, 9 (2, 73) for diarrhea, and 29 (1, 264) for vomiting. For older adults, median day (range) of onset was 4 (1, 286) for diarrhea, 9 (2, 15) for nausea, and 13 (2, 38) for dermatitis acneiform. Time to resolution was variable between TRAEs and among patients in all age groups; 90% resolved completely by DCO. Among all patients, 18 had a TRAE of asymptomatic ejection fraction decrease, with all but one resolving by DCO. CONCLUSIONS Overall, common TRAEs arose before treatment benefits and were generally resoluble by DCO. Proactively managing TRAEs may improve treatment experience and adherence.