anti-LPS IgA Research Articles

Visceral adiposity in postmenopausal women is associated with a pro-inflammatory gut microbiome and immunogenic metabolic endotoxemia

BackgroundObesity, and in particular abdominal obesity, is associated with an increased risk of developing a variety of chronic diseases. Obesity, aging, and menopause are each associated with differential shifts in the gut microbiome. Obesity causes chronic low-grade inflammation due to increased lipopolysaccharide (LPS) levels which is termed “metabolic endotoxemia.” We examined the association of visceral adiposity tissue (VAT) area, circulating endotoxemia markers, and the gut bacterial microbiome in a cohort of aged postmenopausal women.MethodsFifty postmenopausal women (mean age 78.8 ± 5.3 years) who had existing adipose measurements via dual x-ray absorptiometry (DXA) were selected from the extremes of VAT: n = 25 with low VAT area (45.6 ± 12.5 cm2) and n = 25 with high VAT area (177.5 ± 31.3 cm2). Dietary intake used to estimate the Healthy Eating Index (HEI) score was assessed with a food frequency questionnaire. Plasma LPS, LPS-binding protein (LBP), anti-LPS antibodies, anti-flagellin antibodies, and anti-lipoteichoic acid (LTA) antibodies were measured by ELISA. Metagenomic sequencing was performed on fecal DNA. Female C57BL/6 mice consuming a high-fat or low-fat diet were treated with 0.4 mg/kg diet-derived fecal isolated LPS modeling metabolic endotoxemia, and metabolic outcomes were measured after 6 weeks.ResultsWomen in the high VAT group showed increased Proteobacteria abundance and a lower Firmicutes/Bacteroidetes ratio. Plasma LBP concentration was positively associated with VAT area. Plasma anti-LPS, anti-LTA, and anti-flagellin IgA antibodies were significantly correlated with adiposity measurements. Women with high VAT showed significantly elevated LPS-expressing bacteria compared to low VAT women. Gut bacterial species that showed significant associations with both adiposity and inflammation (anti-LPS IgA and LBP) were Proteobacteria (Escherichia coli, Shigella spp., and Klebsiella spp.) and Veillonella atypica. Healthy eating index (HEI) scores negatively correlated with % body fat and anti-LPS IgA antibodies levels. Preclinical murine model showed that high-fat diet-fed mice administered a low-fat diet fecal-derived LPS displayed reduced body weight, decreased % body fat, and improved glucose tolerance test parameters when compared with saline-injected or high-fat diet fecal-derived LPS-treated groups consuming a high-fat diet.ConclusionsIncreased VAT in postmenopausal women is associated with elevated gut Proteobacteria abundance and immunogenic metabolic endotoxemia markers. Low-fat diet-derived fecal-isolated LPS improved metabolic parameters in high-fat diet-fed mice giving mechanistic insights into potential pro-health signaling mediated by under-acylated LPS isoforms.7yVbQmTTfsF9b4Af3tznWNVideo

Abstract 2179: Microbiome-derived metabolites mediate carcinogenic alterations of breast tissue in the context of obesity

Abstract Obesity increases the relative risk for breast cancer incidence. Multiple molecular mechanisms linked to obesity drive breast cancer progression. Obesity shifts the gut microbiome in ways that may increase breast cancer risk. Microbial-associated molecular pattern (MAMP)-proteins and metabolites could directly affect breast epithelial cell signaling. In this study, we focused on lipopolysaccharide (LPS), a structural component of the outer membranes of gram-negative bacteria and a toll-like receptor 4 (TLR4)-agonist. Systemic LPS levels are known to increase in obesity. We hypothesize that chronic low-grade inflammation caused by LPS contributes to breast cancer initiation. To test this hypothesis, we first quantified levels of LPS, along with a panel of adipokines/cytokines, in serum samples from women (n= 33; BMI range= 18.3-45.3 Kg/m2; Age range= 18-51 years). Women with elevated serum LPS had significantly higher BMI, leptin, and leptin/adiponectin ratio, confirming a link between systemic LPS and metabolic markers of obesity. Other biomarkers of breast cancer risk include DNA damage. Analyses of non-cancerous breast tissue sections from matched donors revealed higher densities of DNA double-strand breaks (estimated based on 53BP1 foci counts) in women with high serum LPS. Experiments with HMT-3522 S1 breast acini showed that LPS increases DNA break frequencies and oxidative stress levels in 3D structures of mammary epithelium. Moreover, LPS increases oxidative lesions in the DNA (estimated based on 8-oxoguanine fluorescence in MCF-10A cells) that may lead to increased LPS-mediated DNA damage. Patient obesity status was associated with alterations in oxidative modifications in the breast proteome. We also found that LPS disrupts epithelial polarity, a hallmark of breast tissue homeostasis. In mammary epithelium, LPS activates the nuclear factor-kappa B (NFκB) pathway by binding to the TLR4 receptor, leading to an increased expression of inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α). Interestingly, TLR4 blockade prevented the loss of apical polarity and DNA damage induced by LPS. Last, but not least, we show an association between LPS immunogenicity (anti-LPS IgA concentrations) and participant BMI in non-cancerous breast tissue samples. These novel findings show that LPS is a key systemic and local mediator of the obesity-modulated microbiome that increases breast cancer risk. The outcomes of our study underscore the importance of considering the microbiome in the prevention of breast cancer. Citation Format: Mohamed Gaber, Kayla Neary, Julia Holmes, Adam S. Wilson, Adam J. Katz, Pierre-Alexandre Vidi, Katherine L. Cook. Microbiome-derived metabolites mediate carcinogenic alterations of breast tissue in the context of obesity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2179.

Assessing environmental enteric dysfunction via multiplex assay and its relation to growth and development among HIV-exposed uninfected Tanzanian infants.

Environmental enteric dysfunction (EED) may contribute to poor growth and development in young children. While validated EED biomarkers are currently lacking, multiplex assays are able to capture multiple domains of the condition. The purpose of this exploratory study was to examine the relationship between biomarkers of EED and subsequent growth and development among Tanzanian HIV-exposed uninfected (HEU) infants. We enrolled 467 infants of mothers living with HIV who had participated in a trial of vitamin D3 supplementation during pregnancy. Infant serum samples collected at 6 weeks (n = 365) and 6 months (n = 266) were analyzed for anti-flagellin and anti-lipopolysaccharide (LPS) IgA and IgG via ELISA as well as the 11-plex Micronutrient and EED Assessment Tool (MEEDAT), which incorporates two biomarkers of EED [intestinal fatty acid-binding protein (I-FABP) and soluble CD14 (sCD14)]. Outcomes were 12-month growth [length-for-age z-score (LAZ), weight-for-length z-score (WLZ), and weight-for-age z-score (WAZ)] and development [Caregiver Reported Early Development Instruments (CREDI) z-scores] and were assessed using linear regression. In primary analyses, higher quartiles of 6-month anti-LPS IgG concentrations were significantly associated with lower LAZ at 12 months (ptrend = 0.040). In secondary analyses, higher log2-transformed 6-week anti-flagellin IgA and 6-month anti-LPS IgA concentrations were significantly associated with lower LAZ at 12 months. No associations were observed between I-FABP or sCD14 and infant growth. However, higher log2-transformed 6-week sCD14 concentrations were significantly associated with lower overall CREDI z-scores, while higher log2-transformed 6-month I-FABP concentrations were significantly associated with higher overall CREDI z-scores. Unlike anti-flagellin and anti-LPS Igs, MEEDAT's biomarkers of EED (I-FABP and sCD14) were not associated with subsequent linear growth among HEU infants in Tanzania. The relationship between EED and infant development warrants further study.

Long-Term Kinetics of Serological Antibodies against Vibrio cholerae Following a Clinical Cholera Case: A Systematic Review and Meta-Analysis.

Background: Approximately 2.9 million people worldwide suffer from cholera each year, many of whom are destitute. However, understanding of immunity against cholera is still limited. Several studies have reported the duration of antibodies following cholera; however, systematic reviews including a quantitative synthesis are lacking. Objective: To meta-analyze cohort studies that have evaluated vibriocidal, cholera toxin B subunit (CTB), and lipopolysaccharide (LPS) antibody levels following a clinical cholera case. Methods: Design: Systematic review and meta-analysis. We searched PubMed and Web of science for studies assessing antibodies against Vibrio cholerae in cohorts of patients with clinical cholera. Two authors independently extracted data and assessed the quality of included studies. Random effects models were used to pool antibody titers in adults and older children (aged ≥ 6 years). In sensitivity analysis, studies reporting data on young children (2–5 years) were included. Results: Nine studies met our inclusion criteria for systematic review and seven for meta-analysis. The pooled mean of vibriocidal antibody titers in adults and older children (aged ≥ 6 years) was 123 on day 2 post-symptom onset, which sharply increased on day 7 (pooled mean = 6956) and gradually waned to 2247 on day 30, 578 on day 90, and 177 on day 360. Anti-CTB IgA antibodies also peaked on day 7 (pooled mean = 49), followed by a rapid decrease on day 30 (pooled mean = 21), and further declined on day 90 (pooled mean = 10), after which it plateaued from day 180 (pooled mean = 8) to 360 (pooled mean = 6). Similarly, anti-CTB IgG antibodies peaked in early convalescence between days 7 (pooled mean = 65) and 30 (pooled mean = 69), then gradually waned on days 90 (pooled mean = 42) and 180 (pooled mean = 30) and returned to baseline on day 360 (pooled mean = 24). Anti-LPS IgA antibodies peaked on day 7 (pooled mean = 124), gradually declined on day 30 (pooled mean = 44), which persisted until day 360 (pooled mean = 10). Anti LPS IgG antibodies peaked on day 7 (pooled mean = 94). Thereafter, they decreased on day 30 (pooled mean = 85), and dropped further on days 90 (pooled mean = 51) and 180 (pooled mean = 47), and returned to baseline on day 360 (pooled mean = 32). Sensitivity analysis including data from young children (aged 2–5 years) showed very similar findings as in the primary analysis. Conclusions: This study confirms that serological antibody (vibriocidal, CTB, and LPS) titers return to baseline levels within 1 year following clinical cholera, i.e., before the protective immunity against subsequent cholera wanes. However, this decay should not be interpreted as waning immunity because immunity conferred by cholera against subsequent disease lasts 3–10 years. Our study provides evidence for surveillance strategies and future research on vaccines and also demonstrates the need for further studies to improve our understanding of immunity against cholera.

Assessing Environmental Enteric Dysfunction via Multiplex Assay and its Relation to Infant Growth Among HIV-Exposed Infants in Dar es Salaam, Tanzania

ObjectivesEnvironmental enteric dysfunction (EED), a subclinical state of intestinal inflammation, may contribute to poor growth in children in low-resource settings, but validated biomarkers are lacking. Multiplex assays, such as the 11-plex Micronutrient and EED Assessment Tool (MEEDAT), hold promise due to their ability to capture multiple domains of EED; however, MEEDAT’s ability to predict poor growth has not been well established. We sought to examine the relationship between markers of EED and growth among HIV-exposed infants in Dar es Salaam, Tanzania. MethodsWe performed a sub-study of 467 infants of HIV-infected mothers who participated in a randomized, double-blind, placebo-controlled trial assessing the effect of vitamin D3 supplementation during pregnancy. Infant serum samples collected at 6 weeks and 6 months were analyzed for anti-flagellin and anti-LPS IgA and IgG via ELISA as well as MEEDAT, which incorporates two markers of EED [fatty acid-binding protein (I-FABP) and soluble CD14 (sCD14)]. Biomarkers were categorized into quartiles for primary analyses and as continuous exposures for exploratory analyses. Associations with subsequent growth outcomes [length-for-age Z-score (LAZ), weight-for-length Z-score (WLZ), and weight-for-age Z-score (WAZ)] at 12 months of age were assessed using linear regression. ResultsAt 12 months, nearly half (∼46%) of infants were stunted (LAZ <-2), and ∼3% were wasted (WLZ <-2). Higher concentrations of anti-LPS IgG at 6 months were significantly associated with lower LAZ at 12 months (ptrend = 0.034). In continuous analyses, higher concentrations of anti-flagellin IgA at 6 weeks were significantly associated with lower LAZ at 12 months (β: –0.46, 95% CI: –0.82, –0.11) as were anti-LPS IgA (β: –0.28, 95% CI: –0.53, –0.03) and anti-LPS IgG (β: –0.24, 95% CI: –0.48, –0.01) at 6 months. Higher concentrations of anti-flagellin IgA and anti-LPS IgA at 6 months were significantly associated with lower WAZ at 12 months (β: –0.34, 95% CI: –0.61, –0.07; β: –0.24, 95% CI: –0.44, –0.04). No significant associations were observed between I-FABP or sCD14 and infant growth at 12 months. ConclusionsUnlike anti-flagellin and anti-LPS Igs, MEEDAT’s biomarkers of EED, I-FABP and sCD14, were not associated with subsequent growth among HIV-exposed infants in Tanzania. Funding SourcesNIDDK and NICHD.

Biomarkers of Environmental Enteric Dysfunction in Pregnancy and Adverse Birth Outcomes: An Observational Study Among Women Living With HIV in Tanzania

ObjectivesEnvironmental enteric dysfunction (EED), a subclinical state of intestinal inflammation, may contribute to poor fetal growth in low-resource settings. Pregnant women living with HIV may be particularly susceptible to effects of EED, given their increased risk of infections and adverse birth outcomes. We sought to explore the associations of biomarkers of EED, inflammation and growth hormones with birth outcomes in pregnant women living with HIV in Dar es Salaam, Tanzania.MethodsWe performed a sub-study of 706 HIV-infected pregnant women participating in a randomized, double-blind, placebo-controlled trial assessing the effect of vitamin D3 supplementation. Maternal serum samples collected at 32 weeks gestation were analyzed for anti-flagellin and anti-LPS IgA and IgG via ELISA as well as using an 11-plex Micronutrient and EED Assessment Tool, which includes markers of EED [intestinal fatty acid-binding protein (I-FABP) and soluble CD14], systemic inflammation [C-reactive protein and α1-acid glycoprotein (AGP)], insulin-like growth factor 1 (IGF-1) and fibroblast growth factor 21 (FGF21). Biomarkers were categorized as quartiles. Associations with birth outcomes were assessed using linear regression analyses.ResultsPregnant women in the highest quartile of I-FABP had more than twice the risk of stillbirth compared to those in the lowest quartile (RR 2.43, 95% CI 0.98–6.03, ptrend = 0.02). Compared to women in the lowest quartile of AGP, those in the highest quartile gave birth to infants weighing 176g less (95% CI -280 to -71g, ptrend = 0.005). Maternal AGP was associated with increased risk of small-for-gestational age births; those in the highest quartile had a 70% greater risk compared to the lowest (RR 1.70, 95% CI 1.08–2.69, ptrend = 0.03). IGF1 was positively associated with birthweight and birthweight-for-age z-score; FGF21 was negatively associated with gestation duration and risk of preterm birth.ConclusionsMaternal biomarkers of EED, systemic inflammation, and the growth hormone axis were associated with birth outcomes. Further studies are needed to confirm these results and study the biologic mechanisms involved.Funding SourcesNational Institutes of Health (NICHD, NIDDK).

Anti-LPS IgA and IgG Can Inhibit Serum Killing of Pseudomonas aeruginosa in Patients with Cystic Fibrosis.

Pseudomonas aeruginosa is one of the principal pathogens implicated in respiratory infections of patients with cystic fibrosis (CF) and non-CF bronchiectasis. Previously, we demonstrated that impaired serum-mediated killing of P. aeruginosa was associated with increased severity of respiratory infections in patients with non-CF bronchiectasis. This inhibition was mediated by high titers of O-antigen-specific IgG2 antibodies that cloak the surface of the bacteria, blocking access to the membrane. Infection-related symptomatology was ameliorated in patients by using plasmapheresis to remove the offending antibodies. To determine if these inhibitory "cloaking antibodies" were prevalent in patients with CF, we investigated 70 serum samples from patients with P. aeruginosa infection and 5 from those without P. aeruginosa infection. Of these patients, 32% had serum that inhibited the ability of healthy control serum to kill P. aeruginosa. Here, we demonstrate that this inhibition of killing requires O-antigen expression. Furthermore, we reveal that while IgG alone can inhibit the activity of healthy control serum, O-antigen-specific IgA in patient sera can also inhibit serum-killing. We found that antibody affinity, not just titer, was also important in the inhibition of serum-mediated killing. These studies provide novel insight into cloaking antibodies in human infection and may provide further options in CF and other diseases for treatment of recalcitrant P. aeruginosa infections.

Performance of Immunodiagnostic Tests for Typhoid Fever: A Systematic Review and Meta-Analysis.

Typhoid fever, also known as typhoid, is a life-threatening bacterial infection that remains a global health concern. The infection is associated with a significant morbidity and mortality rate, resulting in an urgent need for specific and rapid detection tests to aid prevention and management of the disease. The present review aims to assess the specificity and sensitivity of the available literature on the immunodiagnostics of typhoid fever. A literature search was conducted using three databases (PubMed, ProQuest and Scopus) and manual searches through the references of identified full texts to retrieve relevant literature published between 1 January 2011 and 31 December 2020. Of the 577 studies identified in our search, 12 were included in further analysis. Lipopolysaccharides (LPS) and hemolysin E (HlyE) were the most frequently studied antigens. The specimens examined in these studies included serum and saliva. Using blood culture as the gold standard, anti-LPS IgA gave the highest sensitivity of 96% (95% CI: 93–99) and specificity of 96% (95% CI: 93–99) for distinguishing between typhoid cases and healthy controls, whereas the combination of anti-LPS and anti-flagellin total IgGAM gave the highest sensitivity of 93% (95% CI: 86–99) and specificity of 95% (95% CI: 89–100) for distinguishing typhoid cases and other febrile infections. A comparably high sensitivity of 92% (95% CI: 86–98) and specificity of 89% (95% CI: 78–100) were shown in testing based on detection of the combination of anti-LPS (IgA and IgM) and anti-HlyE IgG as well as a slightly lower sensitivity of 91% (95% CI: 74–100) in the case of anti-50kDa IgA. Anti-50kDa IgM had the lowest sensitivity of 36% (95% CI: 6–65) against both healthy and febrile controls. The development of a rapid diagnostic test targeting antibodies against lipopolysaccharides combined with flagellin appeared to be a suitable approach for the rapid detection test of typhoid fever. Saliva is added benefit for rapid typhoid diagnosis since it is less invasive. As a result, further studies could be done to develop additional approaches for adopting such samples.

Markers of Environmental Enteric Dysfunction Are Associated with Poor Growth and Iron Status in Rural Ugandan Infants

ABSTRACTBackgroundEnvironmental enteric dysfunction (EED), characterized by altered intestinal permeability/inflammation, microbial translocation, and systemic inflammation (SI), may be a significant contributor to micronutrient deficiencies and poor growth in infants from low-resource settings.ObjectiveWe examined associations among EED, SI, growth, and iron status at 6 mo of age.MethodsWe performed a cross-sectional analysis of 6-mo-old infants (n = 548) enrolled in a Ugandan birth-cohort study (NCT04233944). EED was assessed via serum concentrations of anti-flagellin and anti- LPS immunoglobulins (Igs); SI was assessed via serum concentrations of ɑ1-acid glycoprotein (AGP) and C-reactive protein (CRP); iron status was assessed via serum concentrations of hemoglobin (Hb), soluble transferrin receptor (sTfR), and ferritin. Associations were assessed using adjusted linear regression analysis.ResultsAt 6 mo, ∼35% of infants were stunted [length-for-age z score (LAZ) < −2] and ∼53% were anemic [hemoglobin (Hb) <11.0 g/dL]. Nearly half (∼46%) had elevated AGP (>1 g/L) and ∼30% had elevated CRP (>5 mg/L). EED and SI biomarkers were significantly correlated (r = 0.142–0.193, P < 0.001 for all). In adjusted linear regression models, which included adjustments for SI, higher anti-flagellin IgA, anti-LPS IgA, and anti-LPS IgG concentrations were each significantly associated with lower LAZ [β (95% CI): −0.21 (−0.41, 0.00), −0.23 (−0.44, −0.03), and −0.33 (−0.58, −0.09)]. Furthermore, higher anti-flagellin IgA, anti-flagellin IgG, and anti-LPS IgA concentrations were significantly associated with lower Hb [β (95% CI): −0.24 (−0.45, −0.02), −0.58 (−1.13, 0.00), and −0.26 (−0.51, 0.00)] and higher anti-flagellin IgG and anti-LPS IgG concentrations were significantly associated with higher sTfR [β (95% CI): 2.31 (0.34, 4.28) and 3.13 (0.75, 5.51)].ConclusionsEED is associated with both low LAZ and iron status in 6-mo-old infants. Further research on the mechanisms by which EED affects growth and micronutrient status is warranted.

Markers of Environmental Enteric Dysfunction Are Associated with Poor Growth and Iron Status in Rural Ugandan infants

Abstract Objectives Environmental enteric dysfunction (EED), characterized by altered intestinal permeability/inflammation, microbial translocation, and systemic inflammation (SI), may be a significant contributor to poor growth and micronutrient deficiencies in infants from low-resource setting. The objective of this study was to examine relationships among EED, SI, growth, and iron status in a sample of 6-months old infants from rural Uganda. Methods We performed a cross-sectional analysis using a subset of infants (n = 548) enrolled in a birth cohort study conducted in 16 sub-counties across northern and southwestern Uganda. EED was assessed via serum levels of antibodies to the bacterial components flagellin and lipopolysaccharide (LPS); SI was assessed via serum levels of alpha(1)-acid glycoprotein (AGP) and C-reactive protein (CRP); iron status was assessed via serum levels of hemoglobin (Hb), soluble transferrin receptor (sTfR), and ferritin. Associations were assessed using adjusted linear regression analysis. Results At 6 months, ∼35% of infants were stunted (LAZ &amp;lt; −2), and ∼53% were anemic (Hb &amp;lt; 11.0 g/dL). Nearly half (∼46%) had elevated AGP (&amp;gt;1 g/L) and ∼30% had elevated CRP (&amp;gt;5 mg/L). EED biomarkers were significantly correlated with SI biomarkers (r = 0.142–0.193, P &amp;lt; 0.001 for all). In adjusted linear regression models, which included adjustments for SI, higher anti-flagellin IgA, anti-LPS IgA, and anti-LPS IgG levels were significantly associated with lower LAZ [β: −0.21 (95% CI: −0.41, 0.00), β: −0.23 (95% CI: −0.44, −0.03), and β: −0.33 (95% CI: −0.58, −0.09)]. Furthermore, higher anti-flagellin IgA, anti-flagellin IgG, and anti-LPS IgA levels were significantly associated with lower Hb levels [β: −0.24 (95% CI: −0.45, −0.02), β: −0.58 (95% CI: −1.13, 0.00), and β: −0.26 (95% CI: −0.51, 0.00)]; higher anti-flagellin IgG and anti-LPS IgG levels were significantly associated with higher sTfR levels [β: 2.31 (95% CI: 0.34, 4.28) and β: 3.13 (95% CI: 0.75, 5.51)]. Conclusions Independent of SI, EED is associated with both low LAZ and iron status in 6-months old infants. Further research on the mechanisms by which EED affects growth and micronutrient status is warranted. Funding Sources USAID, award AID-OAA-L-10–00006 to the Friedman School of Nutrition Science and Policy at Tufts University. CD was supported in part by NIH grants K24DK104676 and 2P30 DK040561.

Bacterial Translocation and Risk of Liver Cancer in a Finnish Cohort.

Elevated systemic exposure to gut-derived bacterial products has been associated with hepatic inflammation and chronic liver diseases, potentially increasing the risk of liver cancer. However, only one prior study prospectively examined exposure to bacterial products in the circulation and risk of liver cancer, with a relatively limited coverage of biomarkers. We conducted a nested case-control study (224 liver cancer cases and 224 matched controls) in a large cohort of Finnish male smokers followed from baseline (1985-1988) to 2014. The associations between a panel of biomarkers for bacterial translocation and the risk of liver cancer were assessed using multivariable-adjusted conditional logistic regression. The biomarkers included immunoglobulin (Ig) A, IgG, and IgM against lipopolysaccharide (LPS) and flagellin, soluble CD14 (an LPS coreceptor), and the LPS-binding protein. Anti-flagellin IgA [odds ratios (OR), 2.79; 95% confidence intervals (CI), 1.34-5.78; P trend = 0.01] and anti-LPS IgA (2.44; 95% CI, 1.33-4.48; P trend < 0.01) were significantly associated with risk of liver cancer. When restricting the analysis to histologically classified hepatocellular carcinoma, the ORs were 4.18 (95% CI, 1.60-10.92; P trend < 0.01) and 2.48 (95% CI, 1.16-5.29; P trend < 0.01), respectively. The results were not substantially changed after excluding cases diagnosed within the first 5 years of follow-up and those with hepatitis C virus infection. Antibodies to flagellin and LPS were associated with increased risk of liver cancer. Gut-derived bacterial translocation into the circulation may play a role in the development of primary liver cancer. Our findings could contribute to the understanding of primary liver cancer etiology and further prevention efforts.

Serum anti-flagellin and anti-lipopolysaccharide immunoglobulins as predictors of linear growth faltering in Pakistani infants at risk for environmental enteric dysfunction.

BackgroundEnvironmental Enteric Dysfunction (EED) in children from low-income countries has been linked to linear growth declines. There is a critical need to identify sensitive and early EED biomarkers.ObjectiveDetermine whether levels of antibodies against bacterial components flagellin (flic) and lipopolysaccharide (LPS) predict poor growth.Design/MethodsIn a prospective birth cohort of 380 children in rural Pakistan blood and stool samples were obtained at ages 6 and 9 months. Linear mixed effects models were used to examine longitudinal associations between quartiles of anti-flic and anti-LPS antibodies and changes in LAZ, WAZ and WLZ scores. Spearman’s correlations were measured between anti-flic and anti-LPS immunoglobulins with measures of systemic/enteric inflammation and intestinal regeneration.ResultsAnti-LPS IgA correlated significantly with CRP, AGP and Reg1 serum at 6mo and with MPO at 9mo. In multivariate analysis at 6mo of age, higher anti-LPS IgA levels predicted greater declines in LAZ scores over subsequent 18mo (comparing highest to lowest quartile, β (SE) change in LAZ score/year = -0.313 (0.125), p-value = 0.013). Anti-flic Ig A in the two highest quartiles measured at 9mo of age had declines in LAZ of -0.269 (0.126), p = 0.033; and -0.306 (0.129), p = 0.018 respectively, during the subsequent 18mo of life, compared to those in the lowest quartile of anti-flic IgA.Conclusions and relevanceElevated anti-flic IgA and anti-LPS IgA antibodies at 6 and 9mo, predict declines in linear growth. Systemic and enteric inflammation correlated with anti-LPS IgA provides mechanistic considerations for potential future interventions.

Association between IL-17 and IgA in the joints of patients with inflammatory arthropathies

BackgroundHyperactive secretion and pathogenic effects of interleukin (IL)-17 and IgA have been detected in different arthropathies. Recent evidence has revealed that TH17 cytokines regulate mucosal IgA secretion. However, it is unknown whether and how IL-17 mediates synovial IgA production. Here we aim to investigate the connection of synovial IL-17 with IgA production in the joint.In this study we included synovial fluids (SF) from patients with rheumatoid arthritis (RA; n = 66), spondyloarthritis (SpA; n = 18) and osteoarthritis (OA; n = 36). The levels of IL-17, IL-6, transforming growth factor (TGF)-β1, B-cell-activating factor of the TNF family (BAFF) and anti-lipopolyssacharide (LPS) immunoglobulin (Ig)A were investigated by enzyme-linked immunosorbent assay (ELISA). Total IgA was measured by radial immunodiffusion assay. Synovial fluid-derived mononuclear cells (SFMC) were stimulated with bacterial antigens or SF-conditioned media, and cytokines and IgA were analyzed in the supernatants.ResultsIL-17, IL-6 and TGF-β1 were increased in SF from both RA and SpA compared with OA patients. Concentration of IL-17 correlated with the disease activity score (DAS)-28, IL-6 and anti-LPS IgA levels. Bacterial-stimulated SFMCs from RA and SpA patients secreted higher IL-17 than vehicle-stimulated SFMCs. Conditioned media with SF containing IL-17 induced anti-LPS IgA production by SFMCs which was independent of IL-6 activity. Concentrations of synovial TGF-β1 and BAFF correlated with anti-LPS and total IgA levels, respectively. Blockade of IL-17 decreased the production of TGF-β1 and anti-LPS IgA by SF-stimulated SFMCs.ConclusionsThis study reports a connection between IL-17 and IgA secretion in the joint. In addition, it demonstrates that enterobacterial antigens trigger synovial IL-17 production, and that TGF-β1 and BAFF may mediate the effect of IL-17 on IgA production. This circuit may contribute to the pathogenesis of inflammatory joint diseases.

THE INFLUENCE OF HUMORAL IMMUNITY ANTIENDOTOXIN RESPONSE TO INDICATORS OF SYSTEMIC INFLAMMATION IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Introduction. Systemic lupus erythematosus (SLE) — severe autoimmune disease that has a high level of morbidity and mortality. With each decade the SLE incidence rate grows up. Current researches do not allow to identify the etiology of this disease. The polyclonal stimulation of T and B lymphocytes processes are prevailed in pathogenetic picture of the disease. One of the most powerful triggers of stimulation may be a gram-negative bacteria lipopolysaccharide (LPS) or endotoxin (ET). The impact activity is regulated by a specific humoral and cellular antiendotoxin immune response.Materials and methods. The study group involved 48 patients with SLE, the control group consisted of 40 healthy donors. The material of the study was the venous blood. The following indicators have been identified: the levels of specific anti-endotoxin antibodies (antiLPS IgA, IgM and IgG), by enzyme linked immunosorbent assay (ELISA); concentration of total immunoglobulins IgA, IgM and IgG — microturbidimethric method; the concentration of C-reactive protein (CRP) — ELISA; endogenous intoxication (EI) — a method of determining the average molecular weight for the absorption in the ultraviolet spectrum; circulating immune complexes (CIC) — the method of precipitation in polyethylene glycol. Statistical processing was performed using Microsoft Office Excel 2007 software and MedStat®.Results. The study showed a statistically significant increase in anti-LPSIgG SLE patients by 2.5 times compared with the control group. A slight increase in total IgG by 5%. Endogenous intoxication index in SLE patients was higher by 13.9%, CIC by 150%. The level of CRP in the study group was 6.8 times higher compared with the control. There were also identified the inverse correlation between anti-LPS-IgG and CRP, the inverse correlation between anti-LPS-IgG and EI, direct correlation between anti-LPS-IgA and the age of patients.Discussion. These results indicate the presence of dysfunction in the antiendotoxin immune response (AEIR) in SLE patients, namely increasing concentrations of specific anti-LPS-Ig. Identified growth of indicators of systemic inflammation correlated with indicators of AEIR, that confirms their mutual influence, which contributes to the lesion of organ-targets and can aggravate the manifestation and course of SLE. Normalization of AEIR, elimination of LPS may be a new way of treatment for SLE patients

Elevations in serum anti-flagellin and anti-LPS Igs are related to growth faltering in young Tanzanian children

Antibodies to LPS and flagellin have been described as indirect measures of increased gastrointestinal permeability and may be markers of environmental enteric dysfunction (EED), which is a condition associated with poor child growth. We assessed whether LPS- and flagellin-specific immunoglobulin (Ig) concentrations were associated with poor growth in young Tanzanian children at risk of EED. Blood samples were obtained from 590 children at 6 wk, 6 mo, and 12 mo of age. Serum LPS- and flagellin-specific Ig concentrations (IgA and IgG) were measured with the use of an ELISA. Growth was measured on a monthly basis for 18 mo. Anti-LPS and anti-flagellin IgA and IgG concentrations increased over the first year of life and were higher than concentrations (measured at 9 mo of age) in healthy controls. Children with anti-flagellin IgA, anti-LPS IgA, anti-flagellin IgG, and anti-LPS IgG concentrations in the highest quartile at 6 wk of age were 2.02 (95% CI: 1.11, 3.67), 1.84 (95% CI: 1.03, 3.27), 1.94 (95% CI: 1.04, 3.62), and 2.31 (95% CI: 1.25, 4.27) times, respectively, more likely to become underweight (weight-for-age z score <-2) after adjustment for covariates (P-trend < 0.05) than were children with Ig concentrations in the lowest quartile. Children with increased concentrations of anti-flagellin IgA were also more likely to become wasted; however, there was no association between any of the markers and subsequent stunting. Serologic measures of increased intestinal permeability to bacterial components are associated with subsequent poor growth and could help identify children who may benefit most from preventive interventions. This trial was registered at clinicaltrials.gov as NCT00421668.

Circulating Biomarkers of Gut Barrier Function: Correlates and Nonresponse to Calcium Supplementation among Colon Adenoma Patients.

Gut barrier dysfunction contributes to several gastrointestinal disorders, including colorectal cancer, but factors associated with intestinal hyperpermeability have been minimally studied in humans. We tested the effects of two doses of calcium (1.0 or 2.0 g/d) on circulating biomarkers of gut permeability [anti-flagellin and anti-lipopolysaccharide (LPS) Ig, measured via ELISA] over a 4-month treatment period among colorectal adenoma patients in a randomized, double-blinded, placebo-controlled clinical trial (n = 193), and evaluated the factors associated with baseline levels of these biomarkers. Baseline concentrations of anti-flagellin IgA and anti-LPS IgA were, respectively, statistically significantly proportionately higher by 11.8% and 14.1% among men, 31.3% and 39.8% among those with a body mass index ≥ 35 kg/m(2), and 19.9% and 22.0% among those in the upper relative to the lowest sex-specific tertile of waist circumference. A combined permeability score (the summed optical densities of all four biomarkers) was 24.3% higher among women in the upper tertile of plasma C-reactive protein (Ptrend < 0.01). We found no appreciable effects of supplemental calcium on anti-flagellin or anti-LPS Igs. Our results suggest that (i) men and those with higher adiposity may have greater gut permeability, (ii) gut permeability and systemic inflammation may be directly associated with one another, and (iii) supplemental calcium may not modify circulating levels of gut permeability biomarkers within 4 months. Our findings may improve the understanding of the factors that influence gut permeability to inform development of treatable biomarkers of risk for colorectal cancer and other health outcomes.

Abstract 938: Circulating biomarkers of gut barrier function: Correlates and responses to calcium supplementation among sporadic colorectal adenoma patients in a dose-response randomized controlled trial

Abstract Gut barrier dysfunction contributes to several gastrointestinal disorders, including inflammatory bowel diseases and colorectal cancer, but factors associated with intestinal hyperpermeability have rarely been assessed in human populations, and there is very limited clinical trial evidence on whether gut barrier function may be modified by dietary factors. To address these gaps, we 1) evaluated factors associated with baseline circulating biomarkers of gut barrier function, and 2) tested the effect of calcium on these biomarkers over a 4-month treatment period among patients with previous colorectal adenoma in a randomized, double-blinded, placebo-controlled clinical trial (n = 193). Patients were randomized to placebo (n = 66), 1.0 g calcium (n = 64), or 2.0 g calcium (n = 63) daily. Circulating levels of anti-flagellin and anti-lipopolysaccharide (LPS) immunoglobulins (Igs) as markers of colonic hyperpermeability were measured at baseline and at 4-month follow-up via ELISA. At baseline, mean levels of anti-flagellin and anti-LPS IgA but not IgG were higher among men and those with a larger body mass index (BMI), a larger waist circumference, and higher levels of plasma C-reactive protein. Mean anti-flagellin IgG levels were higher among those with higher proinflammatory cytokine scores. We did not observe effects of calcium on anti-flagellin or anti-LPS Igs: the relative change of a combined permeability score (defined as the sum of the optical densities of all biomarkers) from baseline to follow-up was 0.07 (95% confidence interval [CI] -0.13, 0.27) for each treatment group relative to the placebo group (p-values ≥ 0.5). Our results suggest that 1) men and those with a larger BMI or waist circumference may have greater gut permeability, 2) markers of gut permeability and systemic inflammation may be directly associated with one another, and 3) supplemental calcium administered for 4 months may not modify circulating levels of biomarkers of gut barrier function. Citation Format: Baiyu Yang, Roberd M. Bostick, Andrew T. Gewirtz, Hao Quang Tran, Veronika Fedirko. Circulating biomarkers of gut barrier function: Correlates and responses to calcium supplementation among sporadic colorectal adenoma patients in a dose-response randomized controlled trial. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 938. doi:10.1158/1538-7445.AM2015-938

Preparation and immunogenicity of conjugate based on hydrazine-treated lipopolysaccharide antigen of Vibrio cholerae O139.

A glycoconjugate construct was based on attachment of V. cholerae O139 hydrazine-treated lipopolysaccharide (LPS) to carboxylated bovine serum albumin (CBSA) via its amino group. The immunological properties of the glycoconjugate were tested using BALB/c mice, injected subcutaneously without any adjuvant three times at 2 weeks interval. The immunogenicity of the conjugate was estimated by enzyme-linked immunosorbent assay, testing of anti-LPS IgG, IgM, and IgA antibodies. The conjugate elicited a statistically significant increase of LPS-specific IgG levels in mice (p < 0.001). The specific anti-LPS IgG and IgA response after the second booster dose was significantly higher compared with reference and unconjugated detoxified LPS response. Antibodies elicited by the dLPS-CBSA conjugate were vibriocidal.

Repeated oronasal exposure to lipopolysaccharide induced mucosal IgA responses in periparturient dairy cows.

This study investigated the effects of repeated oronasal treatment with lipopolysaccharide (LPS) on the humoral immune responses in saliva, vaginal mucus, and the plasma markers of the acute phase response in periparturient dairy cows. One hundred pregnant Holstein cows were administered either 3 increasing doses of LPS (n = 50) as follows: 1) 0.01 µg/kg body weight (BW) on d −28, 2) 0.05 µg/kg BW on d −25, and −21, and 3) 0.1 µg/kg BW on d −18, and −14, or sterile saline solution (controls; n = 50) oronasally for 3 consecutive wk starting at 28 d before parturition. Intensive sampling was conducted on thirty cows (n = 15/group). Multiple saliva, vaginal mucus and blood samples were collected around parturition and analyzed for total immunoglobulin-(Ig)A, plasma serum amyloid A (SAA), lipopolysaccharide-binding protein (LBP), anti-LPS IgA, IgG, IgM, tumour necrosis factor(TNF)-α, and interleukin(IL)-1. Results regarding total secretory IgA (sIgA) antibodies showed greater concentrations in the saliva and an overall tendency for higher total sIgA in the vaginal mucus of the LPS-treated cows. Treatment had no effect on plasma sIgA, IgG, IgM anti-LPS antibodies, haptoglobin, SAA, LBP, TNF-α, and IL-1. Treatments by time interactions were observed for SAA and IL-1 with lowered concentrations of both variables in the plasma of LPS-treated cows after parturition. Overall, repeated oronasal LPS treatment clearly enhanced total sIgA antibodies in the saliva, stimulated their production in vaginal mucus shortly before calving, and lowered plasma IL-1 around parturition, but showed limited effects on markers of the acute phase response in the plasma in dairy cows around parturition.

Increased Anti-Flagellin and Anti-Lipopolysaccharide Immunoglobulins in Pediatric Intestinal Failure: Associations With Fever and Central Line-Associated Bloodstream Infections.

Central line-associated bloodstream infections (CLABSIs) pose a significant challenge in the lives of patients with intestinal failure (IF). We hypothesized that plasma immunoglobulins against flagellin (FLiC) and lipopolysaccharide (LPS) would be able to differentiate CLABSIs from nonbacterial febrile episodes and that levels would increase with infection and decline following appropriate antibiotic treatment. Patients with IF, due to short bowel syndrome, between the ages of 3 months and 4 years of age, were recruited at Cincinnati Children's Hospital Medical Center. Anti-FLiC and anti-LPS plasma antibody levels were measured in 13 children with IF at baseline, during febrile events, and also following treatment with antibiotics. These were also measured in 11 healthy children without IF who were recruited as controls. Plasma anti-FLiC IgA levels increased during febrile episodes in all patients with IF (baseline mean of 1.10 vs febrile episode mean of 1.32 optical density units, respectively; P = .046). Neither plasma anti-FLiC nor anti-LPS IgA or IgG levels distinguished CLABSI from nonbacterial febrile episodes compared with baseline levels. Compared with controls, patients with IF had significantly higher plasma levels of anti-FLiC and anti-LPS IgA at baseline. Plasma anti-FLiC IgA antibody levels rise during febrile episodes but do not differentiate between nonbacterial febrile illnesses and CLABSIs in pediatric IF. However, the upregulation of these antibodies in IF suggests the baseline systemic presence of Gram-negative bacterial products.