Digital dermatitis in Swedish dairy herds assessed by ELISA targeting Treponema phagedenis in bulk tank milk.

BACKGROUND: Digital dermatitis (DD) is a contagious hoof infection affecting cattle worldwide. The disease causes lameness and a reduction in animal welfare, which ultimately leads to major decreases in milk production in dairy cattle. The disease is most likely of polymicrobial origin with Treponema phagedenis and other Treponema spp. playing a key role; however, the etiology is not fully understood. Diagnosis of the disease is based on visual assessment of the feet by trained hoof-trimmers and veterinarians, as a more reliable diagnostic method is lacking. The aim of this study was to evaluate the use of an enzyme-linked immunosorbent assay (ELISA) on bulk tank milk samples testing for the presence of T. phagedenis antibodies as a proxy to assess herd prevalence of DD in Swedish dairy cattle herds. RESULTS: Bulk tank milk samples were collected in 2013 from 612 dairy herds spread across Sweden. A nationwide DD apparent prevalence of 11.9% (8.1-14.4% CI95%) was found, with the highest proportion of test-positive herds in the South Swedish regions (31.3%; 19.9-42.4% CI95%). CONCLUSIONS: This study reveals an underestimation of DD prevalence based on test results compared to hoof trimming data, highlighting the critical need for a reliable and accurate diagnostic method. Such a method is essential for disease monitoring and the development of effective control strategies. The novelty of ELISA-based diagnostic methods for DD, coupled with the disease's polymicrobial origin, suggests an avenue for improvement. Developing an expanded ELISA, incorporating antigens from various bacterial species implicated in the disease, could enhance diagnostic accuracy. The significance of this study is underscored by the extensive analysis of a substantial sample size (612). Notably, this investigation stands as the largest assessment to date, evaluating the application of ELISA on bulk tank milk for DD diagnosis at the herd level.

Comparison of the Euroimmun Borrelia 'antibody index' with Virotech immunoblot-based detection of intrathecal Borrelia antibody production for the diagnosis of Lyme neuroborreliosis.

For diagnosis of neuroborreliosis, calculation of the antibody index, based on Euroimmun Anti-Borrelia plus VlsE ELISA was compared to Virotech Borrelia Europe plus TpN17 immunoblot-based detection of Borrelia-specific intrathecal antibody production. CXCL13 results in cerebrospinal fluid were used to evaluate discordant results. A total of 64 serum/CSF pairs were analysed. Patients were classified according to European Federation of Neurological Societies criteria incorporating Virotech results. For the Euroimmun assay, a sensitivity of 100% and specificity of 94% was found. Agreement between the both tests was almost perfect (κ 0.81). Both methods are appropriate for the detection of Borrelia-specific intrathecal antibody production.

Correlates of immune exacerbations in leprosy.

Leprosy is still a considerable health threat in pockets of several low and middle income countries worldwide where intense transmission is witnessed, and often results in irreversible disabilities and deformities due to delayed- or misdiagnosis. Early detection of leprosy represents a substantial hurdle in present-day leprosy health care. The dearth of timely diagnosis has, however, particularly severe consequences in the case of inflammatory episodes, designated leprosy reactions, which represent the major cause of leprosy-associated irreversible neuropathy. There is currently no accurate, routine diagnostic test to reliably detect leprosy reactions, or to predict which patients will develop these immunological exacerbations. Identification of host biomarkers for leprosy reactions, particularly if correlating with early onset prior to development of clinical symptoms, will allow timely interventions that contribute to decreased morbidity. Development of a point-of-care (POC) test based on such correlates would be a definite game changer in leprosy health care. In this review, proteomic-, transcriptomic and metabolomic research strategies aiming at identification of host biomarker-based correlates of leprosy reactions are discussed, next to external factors associated with occurrence of these episodes. The vast diversity in research strategies combined with the variability in patient- and control cohorts argues for harmonisation of biomarker discovery studies with geographically overarching study sites. This will improve identification of specific correlates associated with risk of these damaging inflammatory episodes in leprosy and subsequent application to rapid field tests.

Identification of a novel protective human monoclonal antibody, LXY8, that targets the key neutralizing epitopes of staphylococcal enterotoxin B.

Staphylococcal enterotoxin B (SEB), one of the exotoxins produced by Staphylococcus aureus, is the key toxin that causes poisoning reactions and toxic shock syndrome. In the current research work, a novel human antibody named LXY8 was screened from a human phage display antibody library, and LXY8 blocked the interaction between SEB and the T cell receptor (TCR). The binding activity between LXY8 and SEB was 0.525 nM. Furthermore, LXY8 could effectively inhibit the SEB-induced activation of peripheral blood mononuclear cells and release of cytokines. In the BALB/c mouse model, LXY8 effectively neutralized SEB toxicity in vivo. Finally, based on computer-guided molecular modeling, we designed a series of SEB mutation sites; these sites facilitated the determination of the key residues (i.e.176EFNN179) of SEB recognized by LXY8. The research revealed that the 176EFNN179 residues of SEB are important for specific antibody-antigen recognition. The results may be helpful for the development of antibody-based therapy for SEB-induced toxic shock syndrome.

The antibody response to the glycan α-Gal correlates with COVID-19 disease symptoms.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide. Characterization of the immunological mechanisms involved in disease symptomatology and protective response is important to progress in disease control and prevention. Humans evolved by losing the capacity to synthesize the glycan Galα1-3Galß1-(3)4GlcNAc-R (α-Gal), which resulted in the development of a protective response against pathogenic viruses and other microorganisms containing this modification on membrane proteins mediated by anti-α-Gal immunoglobulin M (IgM)/IgG antibodies produced in response to bacterial microbiota. In addition to anti-α-Gal antibody-mediated pathogen opsonization, this glycan induces various immune mechanisms that have shown protection in animal models against infectious diseases without inflammatory responses. In this study, we hypothesized that the immune response to α-Gal may contribute to the control of COVID-19. To address this hypothesis, we characterized the antibody response to α-Gal in patients at different stages of COVID-19 and in comparison with healthy control individuals. The results showed that while the inflammatory response and the anti-SARS-CoV-2 (Spike) IgG antibody titers increased, reduction in anti-α-Gal IgE, IgM, and IgG antibody titers and alteration of anti-α-Gal antibody isotype composition correlated with COVID-19 severity. The results suggested that the inhibition of the α-Gal-induced immune response may translate into more aggressive viremia and severe disease inflammatory symptoms. These results support the proposal of developing interventions such as probiotics based on commensal bacteria with α-Gal epitopes to modify the microbiota and increase α-Gal-induced protective immune response and reduce severity of COVID-19.

Immune profiling of breast milk from mothers with treated celiac disease.

BACKGROUND: The protective effect of breastfeeding on celiac disease (CD) onset is controversial. We studied a wide range of milk components in milk produced by celiac mothers following long-term gluten-free diet (GFD) in comparison to milk produced by healthy mothers. METHODS: Breast-milk samples from celiac (n = 33) and healthy (n = 41) mothers were obtained during the first year of lactation. A panel of bioactive components was analyzed by enzyme-linked immunosorbent assay in the aqueous fraction. We studied molecules involved in defenses, immunoregulation, and strengthening of the gut-epithelial barrier. RESULTS: During late lactation (from 6 to 12 months after delivery), the content of total immunoglobulin A (IgA) and IgM was significantly lower in the milk produced by celiac patients. Nevertheless, gliadin (GFD)-specific IgA relative contribution was higher in this group, in contrast to tetanus toxoid-specific antibodies. The balance between pro-inflammatory and anti-inflammatory molecules was different. While interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 were most frequently found in samples from celiac mothers, soluble Toll-like receptor-2 prevalence was lower. CONCLUSIONS: We describe differences between the innate and adaptive immune profile of milk produced by celiac and healthy mothers. These results might explain previous controversial reports about breastfeeding and CD protection. IMPACT: In spite of a long-term adherence to GFD, the milk produced by mothers with CD exhibit a different immune profile, in relation with some immunoregulatory factors and antibody content. This work shows a more comprehensive characterization of milk from celiac mothers, including macronutrients, lysozymes, growth factors, and immunoregulatory components that had not been studied before. The present study widens the available data regarding the characteristics of human milk of celiac mothers following GFD. Further follow-up studies of the health of children who were breastfed by celiac mothers will be necessary in order to also estimate the impact of the present results therein.

Effect of O-Antigen Chain Length Regulation on the Immunogenicity of Shigella and Salmonella Generalized Modules for Membrane Antigens (GMMA).

Recently, generalized modules for membrane antigens (GMMA) technology has been proposed as an alternative approach to traditional glycoconjugate vaccines for O-antigen delivery. Saccharide length is a well-known parameter that can impact the immune response induced by glycoconjugates both in terms of magnitude and quality. However, the criticality of O-antigen length on the immune response induced by GMMA-based vaccines has not been fully elucidated. Here, Shigella and Salmonella GMMA-producing strains were further mutated in order to display homogeneous polysaccharide populations of different sizes on a GMMA surface. Resulting GMMA were compared in mice immunization studies. Athymic nude mice were also used to investigate the involvement of T-cells in the immune response elicited. In contrast with what has been reported for traditional glycoconjugate vaccines and independent of the pathogen and the sugar structural characteristics, O-antigen length did not result in being a critical parameter for GMMA immunogenicity. This work supports the identification of critical quality attributes to optimize GMMA vaccine design and improve vaccine efficacy and gives insights on the nature of the immune response induced by GMMA.

Effect of methanolic extract of Citrus limetta peel on cellular and humoral immune response in mice.

Citrus limetta is well known for its anti-inflammatory, antimicrobial, antifungal, antidiabetic and antioxidant properties. Methanolic extract of Citrus limetta (MECL) was used to assess cellular and humoral immune responses in mice by carrying out cyclophosphamide-induced neutropenia, delayed-type hypersensitivity (DTH), carbon clearance assay, haemagglutination assay (HA) and mice lethality assay. Methanolic extract of Citrus limetta peel was administered orally to mice in two doses 200mg/kg and 400mg/kg.The extract treated groups showed improvement in neutropenia induced by cyclophosphamide and improvement in the WBC profile. Skin thickness was significantly (P<0.05) higher in 200mg/kg and 400mg/kg groups in comparison to control in DTH. The phagocytic index was significantly (P<0.05) more in 400mg/kg group in carbon clearance assay. Mice were vaccinated with hemorrhagic septicemia vaccine before challenge with Pasteurella multocida for mice lethality test. Percentage mortality was decreased in 400mg/kg treated group in comparison to negative control Antibody titre response to sheep red blood cells was significantly (P<0.05) higher with dose 400mg/kg in HA. Results suggested the effectiveness of the methanolic extract of Citrus limetta as an immunostimulating agent.

Development and evaluation of an up-converting phosphor technology-based lateral flow assay for rapid and quantitative detection of Coxiella burnetii phase I strains.

BACKGROUND: Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes a zoonotic disease commonly called Q fever globally. In this study, an up-converting phosphor technology-based lateral flow (UPT-LF) assay was established for the rapid and specific detection of phase I strains of C. burnetii. RESULTS: Specific monoclonal antibodies (10B5 and 10G7) against C. burnetii phase I strains were prepared and selected for use in the UPT-LF assay by the double-antibody-sandwich method. The detection sensitivity of the Coxiella-UPT-LF was 5 × 104 GE/ml for a purified C. burnetii phase I strain and 10 ng/ml for LPS of C. burnetii Nine Mile phase I (NMI). Good linearity was observed for C. burnetii phase I and NMI LPS quantification (R2 ≥ 0.989). The UPT-LF assay also exhibited a high specificity to C. burnetii, without false-positive results even at 108 GE/ml of non-specific bacteria, and good inclusivity for detecting different phase I strains of C. burnetii. Moreover, the performance of the Coxiella-UPT-LF assay was further confirmed using experimentally and naturally infected samples. CONCLUSIONS: Our results indicate that Coxiella-UPT-LF is a sensitive and reliable method for rapid screening of C. burnetii, suitable for on-site detection in the field.

An outbreak of relapsing fever unmasked by microbial paleoserology, 16th century, France.

OBJECTIVES: Depicting past epidemics currently relies on DNA-based detection of pathogens, an approach limited to pathogens with well-preserved DNA sequences. We used paleoserology as a complementary approach detecting specific antibodies under a mini line-blot format including positive and negative control antigens. METHODS: Mini line blot assay incorporated skim milk as negative control, Staphylococcus aureus as positive control, and antigens prepared from lice-borne pathogens Rickettsia prowazekii, Borrelia recurrentis, Bartonella quintana, and Yersinia pestis. Paleoserums were extracted from rehydrated dental pulp recovered from buried individuals. Mini line blots observed with the naked eye, were quantified using a scanner and appropriate software. Paleoserology was applied to the indirect detection of lice-borne pathogens in seven skeletons exhumed from a 16th-17th century suspected military burial site (Auxi-le-Château); and 14 civils exhumed from a 5th-13th century burial site (Saint-Mont). Direct detection of pathogens was performed using quantitative real-time PCR. RESULTS: In Auxi-le-Château, paleoserology yielded 7/7 interpretable paleoserums including 7/7 positives for B. recurrentis including one also positive for B. quintana. In Saint-Mont, paleoserology yielded 8/14 interpretable paleoserums and none reacted against any of the four pathogens. Antibodies against R. prowazekii and Y. pestis were not detected. The seroprevalence was significantly higher in the military burial site of Auxi-le-Château than in the civil burial site of Saint-Mont. Real-time PCR detection of B. quintana yielded 5/21 positive (3 at Saint-Mont and 2 at Auxi-le-Château) whereas B. recurrentis was not detected. CONCLUSIONS: Paleoserology unmasked an outbreak of relapsing B. recurrentis fever in one 16th - 17th century military garrison, missed by real-time PCR. Paleoserology offers a new tool for investigating past epidemics, in complement to DNA sequence-based approaches.

Evaluation of a standardised Vi poly-l-lysine ELISA for serology of Vi capsular polysaccharide antibodies.

Typhoid vaccines based on protein-conjugated capsular Vi polysaccharide (TCVs) prevent typhoid in infants and young children. Analysis of the serum anti-Vi IgG response following immunisation against typhoid confirms the immunogenicity of TCVs and forms an important part of the pathway to licensing. Comparative studies could expedite the licencing process, and the availability of a standardised ELISA method alongside the 1st International Standard (IS) 16/138 for anti-typhoid capsular Vi polysaccharide IgG (human) will facilitate this process. To this end, a non-commercial ELISA based on a coat of Vi and poly-l-lysine (Vi-PLL ELISA) was evaluated by 10 laboratories. Eight serum samples, including IS 16/138, were tested in the standardised Vi-PLL ELISA (n = 10), a commercial Vi ELISA (n = 3) and a biotinylated Vi ELISA (n = 1). Valid estimates of potencies relative to IS 16/138 were obtained for all samples in the Vi-PLL ELISA and the commercial ELISA, with good repeatability and reproducibility evident from the study results and concordant estimates obtained by the two ELISA methods. The study demonstrates that the Vi-PLL ELISA can be used in clinical trial studies to determine the immunogenicity of TCVs.

Clinical utility of aqueous humor polymerase chain reaction and serologic testing for suspected infectious uveitis: a single-center retrospective study in South Korea.

BACKGROUND: This study aimed to assess and compare the clinical value of aqueous humor polymerase chain reaction (PCR) and serologic tests in patients diagnosed with suspected infectious uveitis. METHODS: In this retrospective observational study, data of 358 patients who were diagnosed with suspected infectious uveitis and who underwent aqueous humor PCR testing were analyzed. PCR and serologic test results were compared with the clinical features. RESULTS: The rates of initial diagnoses for infectious uveitis were higher with PCR (99 patients, 28%) compared to those with serologic tests (38 pateints, 11%). The diagnostic positivity of PCR was 29% for anterior uveitis, 0% for intermediate uveitis, 5% for posterior uveitis, and 30% for panuveitis. In particular, PCR was useful in confirming the diagnosis of cytomegalovirus and varicella-zoster virus infections and Toxoplasma gondii-associated uveitis. For PCR test, the sensitivity was 0.431, specificity was 0.985, and the negative and positive predictive values were 0.506 and 0.980, respectively. For IgM test, the sensitivity was 0.151, specificity was 0.970, and the negative and positive predictive values were 0.403 and 0.895, respectively. CONCLUSION: Aqueous humor PCR can be a valuable diagnostic tool for confirming the infectious etiology in patients clinically diagnosed with uveitis. PCR had good predictive and diagnostic value for anterior uveitis and panuveitis compared with that for intermediate and posterior uveitis.

Anatomical and biochemical evidence for Treponema pallidum in a 19th to early twentieth century skeletal cadaver.

This report summarizes findings relating to the biochemical and skeletal evidence for Treponema pallidum in an unusually old case of congenital syphilis. In 1951, the Milwaukee Public Museum acquired skeletal remains from the Surgical School of Marquette University. The male was identified as a 60-65-year-old, that was suffering from congenital syphilis. His remains are now part of the anthropological collections of Wisconsin Lutheran College (Milwaukee, Wisconsin). Venereal Disease Research Laboratory (VDRL) and Rapid Plasma Reagin (RPR) tests were used to verify the presence of the bacteria-generated antibodies, while mass spectrometry testing provided indirect evidence for the historical treatment of the disease. Notably, antibody detection in human remains of this age is rare. These initial results support what is known of syphilis and its treatment prior to the wide scale, clinical use of penicillin therapy, and describe evidence for long-term skeletal symptoms of congenital syphilis in century-old human remains.

[Meta-analysis on tetanus antibody protection rate of healthy population born after 1978 in China].

Objective: Meta-analysis was conducted on the tetanus antibody protection rate of healthy population born after 1978 in China (data from Hong Kong, Macao and Taiwan was excluded, the same below). Methods: Search the data on China's tetanus antibody level which were published in China National Knowledge Infrastructure, Wanfang data, VIP, SinoMed database, PubMed and the Cochrane Library. The Chinese search keywords were "Tetanus Antitoxin", "Tetanus Antibody", "Healthy Population" and "Mainland China". English search terms include "tetanus antitoxin", "tetanus vaccine", "tetanus vaccine", "general population" and "mainland of China". The time limit for inclusion in literature research was 2010-2019. Stata software was used to conduct meta-analysis on the protection rate of tetanus antibody. Results: A total of 24 articles were included. There was no obvious publication bias in the included articles. The total number of respondents was 23 530, the antibody protection rate was 49.5%-99.0%. A total of 20 817 people got effective antibody protection, which meant the antibody level reached and exceeded 0.1 IU/ml, and the combined protection rate was 78.6% (95%CI: 75.0%-88.2%). The combined protection rates of antibody in 0-7 years old and 8-15 years old groups were 88.9% (95%CI: 86.9%-91.0%) and 79.3% (95%CI: 72.9%-86.2%) respectively. The combined protection rates of antibodies in 16-20 years old, 21-30 years old and 31-40 years old groups were 58.9% (95%CI: 46.5%-71.2%), 47.7% (95%CI: 16.8%-78.7%) and 63.8% (95%CI:32.6%-95.1%) respectively. The combined protection rate of tetanus antibody for 0-15 years old people was 85.6% (95%CI: 83.1%-88.1%), and the combined protection rate of antibody for 16-40 years old people was 52.9% (95%CI: 39.3%-66.6%). Conclusion: With the increase of age, the protection rate of tetanus antibody among the healthy population aged 16-40 years in our country decreases. An individualized vaccination plan should be formulated according to the previous tetanus vaccination history and the tetanus antibody level when necessary.

Immunomagnetic separation and Listeriamonocytogenes detection with surface-enhanced Raman scattering

Background/aim: We aimed to develop a rapid method to enumerate Listeria monocytogenes (L. monocytogenes) utilizing magnetic nanoparticle based preconcentration and surface-enhanced Raman spectroscopy measurements. Materials and methods: Biological activities of magnetic Au-nanoparticles have been observed to have the high biocompatibility, and a sample immunosensor model has been designed to use avidin attached Au-nanoparticles for L. monocytogenes detection. Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) bacteria cultures were chosen for control studies. Antimicrobial activity studies have been done to identify bio-compatibility and bio-characterization of the Au-nanoparticles in our previous study and capturing efficiencies to bacterial surfaces have been also investigated. Results: We constructed the calibration graphs in various population density of L. monocytogenes as 2.2 × 101 to 2.2 × 106 cfu/mL and the capture efficiency was found to be 75%. After the optimization procedures, population density of L. monocytogenes and Raman signal intensity showed a good linear correlation (R2 = 0.991) between 102 to 106 cfu/mL L. monocytogenes. The presented sandwich assay provides low detection limits and limit of quantification as 12 cfu/mL and 37 cfu/mL, respectively. We also compared the experimental results with reference plate-counting methods and the practical utility of the proposed assay is demonstrated using milk samples. Conclusion: It is focused on the enumeration of L. monocytogenes in milk samples and the comparision of results of milk analysis obtained by the proposed SERS method and by plate counting method stay in food agreement. In the present study, all parameters were optimized to select SERS-based immunoassay method for L. monocytogenes bacteria to ensure LOD, selectivity, precision and repeatablity.

[Studying the possibility of using immuno-enzy test system for evaluating anti-pertussis immunity.]

A research objective - to study the possibility of using the ELISA Anti-K enzyme immunoassay system to evaluate anti-pertussis immunity. А comparative assessment of the content of co-crank antibodies in the blood serum of adults, pregnant women and children 6 years old in the agglutination test, in the test system "Anti-K ELISA" and test systems of foreign production was carried out. The "Anti-K" IFA test system makes it possible to detect the level of specific antibodies to both the whole cell and cell-free pertussis component of the vaccine at any stage of the vaccination cycle. This diagnostic test can be used to determine the tactics of immunization, and to assess population immunity.

Intranasal co-administration of recombinant active fragment of Zonula occludens toxin and truncated recombinant EspB triggers potent systemic, mucosal immune responses and reduces span of E. coli O157:H7 fecal shedding in BALB/c mice.

Escherichia coli O157:H7 with its traits such as intestinal colonization and fecal-oral route of transmission demands mucosal vaccine development. E. coli secreted protein B (EspB) is one of the key type III secretory system (TTSS) targets for mucosal candidate vaccine due to its indispensable role in the pathogenesis of E. coli O157:H7. However, mucosally administered recombinant proteins have low immunogenicity which could be overcome by the use of mucosal adjuvants. The quest for safe, potent mucosal adjuvant has recognized ΔG fragment of Zonula occludens toxin of Vibrio cholerae with such properties. ΔG enhances mucosal permeability via the paracellular route by altering epithelial tight junction structure in a reversible, ephemeral and non-toxic manner. Therefore, we tested whether recombinant ΔG intranasally co-administered with truncated EspB (EspB + ΔG) could serve as an effective mucosal adjuvant. Results showed that EspB + ΔG group induced higher systemic IgG and mucosal IgA than EspB alone. Moreover, EspB alone developed Th2 type response with IgG1/IgG2a ratio (1.64) and IL-4, IL-10 cytokines whereas that of EspB + ΔG group generated mixed Th1/Th2 type immune response evident from IgG1/IgG2a ratio (1.17) as well as IL-4, IL-10 and IFN-γ cytokine levels compared to control. Sera of EspB + ΔG group inhibited TTSS mediated haemolysis of murine RBCs more effectively compared to EspB, control group and sera of both EspB + ΔG, EspB group resulted in similar levels of efficacious reduction in E. coli O157:H7 adherence to Caco-2 cells compared to control. Moreover, vaccination with EspB + ΔG resulted in significant reduction in E. coli O157:H7 fecal shedding compared to EspB and control group in experimentally challenged streptomycin-treated mice. These results demonstrate mucosal adjuvanticity of ΔG co-administered with EspB in enhancing overall immunogenicity to reduce E. coli O157:H7 shedding.

Helicobacter pylori infection is not associated with rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is an autoinflammatory disease caused by genetic susceptibility and environmental triggers, which include infectious agents. Helicobacter pylori, a bacterium that frequently colonizes the stomach, is associated with the development of certain autoinflammatory disorders. This study examined a possible association between H. pylori infection and RA. METHOD: This cohort study was performed in the Central Denmark Region. Patients were enrolled from primary healthcare centres after a urea breath test (UBT) for H. pylori and followed for a median of 8 years. Nationwide administrative registries provided information about the patients' diagnoses, country of birth, and gender. Comorbidity was determined using the Charlson Comorbidity Index. We compared the prevalence of RA via odds ratios (ORs) and incidences using Cox regression to calculate the hazard ratios (HRs) by comparing H. pylori-positive and H. pylori-negative individuals and adjusting for confounding variables. RESULTS: A total of 56 000 people diagnosed as H. pylori positive or negative had similar rates of comorbidity. No link was found between H. pylori and RA. There was no difference in RA prevalence until time of UBT [OR = 0.91, 95% confidence interval (CI) 0.70-1.19)] or incidence of new RA cases after UBT (HR = 0.80, 95% CI 0.56-1.13) between H. pylori-positive and -negative subjects. Validation via four other RA definitions provided similar results. CONCLUSION: This study found no association between H. pylori infection and RA. This result does not support the involvement of H. pylori in a gut-joint axis of importance for RA development.

Use of saliva to monitor meningococcal vaccine responses: proposing a threshold in saliva as surrogate of protection.

BACKGROUND: Mucosal antibodies against capsular polysaccharides offer protection against acquisition and carriage of encapsulated bacteria like Neisseria meningitidis serogroup C. Measurements of salivary antibodies as replacement for blood testing has important (cost-effective) advantages, particular in studies that assess the impact of large-scale vaccination or in populations in which blood sampling is difficult. This study aimed to estimate a threshold for meningococcal IgG salivary antibody levels to discriminate between unprotected and protected vaccinated individuals. METHODS: MenA-, MenC-, MenW- and MenY-polysaccharide (PS) specific IgG levels in serum and saliva from participants in a meningococcal vaccination study were measured using the fluorescent-bead-based multiplex immunoassay. Functional antibody titers in serum against the four serogroups were measured with serum bactericidal assay using rabbit complement (rSBA). A threshold for salivary IgG was determined by analysis of ROC curves using a serum rSBA titer ≥128 as correlate of protection. The area under the curve (AUC) was calculated to quantify the accuracy of the salivary test and was considered adequate when ≥0.80. The optimal cut-off was considered adequate when salivary IgG cut-off levels provided specificity of ≥90%. True positive rate (sensitivity), positive predictive value, and negative predictive value were calculated to explore the possible use of salivary antibody levels as a surrogate of protection. RESULTS: The best ROC curve (AUC of 0.95) was obtained for MenC, with an estimated minimum threshold of MenC-PS specific salivary IgG ≥3.54 ng/mL as surrogate of protection. An adequate AUC (> 0.80) was also observed for MenW and MenY with an estimated minimal threshold of 2.00 and 1.82 ng/mL, respectively. When applying these thresholds, all (100%) samples collected 1 month and 1 year after the (booster) meningococcal vaccination, that were defined as protective in the saliva test for MenC, MenW and MenY, corresponded with concomitant serum rSBA titer ≥128 for the respective meningococcal serogroups. CONCLUSION: The saliva test offers an alternative screening tool to monitor protective vaccine responses up to one year after meningococcal vaccination against MenC, MenW and MenY. Future (large) longitudinal vaccination studies evaluating also clinical protection against IMD or carriage acquisition are required to validate the currently proposed threshold in saliva.

Cost-effectiveness of Helicobacter pylori test and eradication versus upper gastrointestinal series versus endoscopy for gastric cancer mortality and outcomes in high prevalence countries.

Background: The latest version of Japanese guidelines for effective secondary prevention of gastric cancer recommend upper gastrointestinal series (UGI) and endoscopy in adults 50 years of age and older. A Helicobacter pylori antibody test and eradication (H. pylori screening) reduces gastric cancer risk. Objective: This study aimed to evaluate the cost-effectiveness of H. pylori screening, compared to UGI and endoscopy in high prevalence countries. Methods: We developed decision trees with Markov models using a healthcare payer perspective and a lifetime horizon. Targeted populations were hypothetical cohorts of asymptomatic individuals at the age of 50, 60, 70 and 80 years. We calculated per-person costs and effectiveness with discounting at a fixed annual rate of 3% and compared incremental cost-effectiveness ratios. Results: H. pylori screening was cost-saving and more cost-effective for individuals at the age of 50, 60, 70, and 80 than UGI and endoscopy. One-way and multiway sensitivity analyses showed the robustness of the cost-effectiveness results. Probabilistic sensitivity analyses using Monte-Carlo simulation for 10,000 trials demonstrated that H. pylori screening was cost-effective 100% of the time at a willingness-to-pay level of US$50,000/QALY gained. Conclusions: H. pylori screening for the adults 50 years of age and older could be cost-effective compared to UGI and endoscopy in high prevalence countries. The main reasons for the superiority of H. pylori screening are that an H. pylori antibody test has a higher sensitivity and specificity than UGI and endoscopy and the benefits to reduce gastric cancer incidence and mortality.