Immunoinformatics-Based Designing of Novel and Potent Multi-Epitope PSA D15 and Cag11 Immunogens for Helicobacter pylori Immunodiagnostic Assay Development.

Helicobacter pylori (H. pylori) strain is the most genetically diverse pathogenic bacterium and now alarming serious human health concern ranging from chronic gastritis to gastric cancer and human death all over the world. Currently, the majority of commercially available diagnostic assays for H. pylori is a challenging task due to the heterogeneity of virulence factors in various geographical regions. In this concern, designing of universal multi-epitope immunogenic biomarker targeted for all H. pylori strains would be crucial to successfully immunodiagnosis assay and vaccine development for H. pylori infection. Hence, the present study aimed to explore the potential immunogenic epitopes of PSA D15 and Cag11 proteins of H. pylori, using immunoinformatics web tools in order to design novel immune-reactive multi-epitope antigens for enhanced immunodiagnosis in humans. Through an in silico immunoinformatics approach, high-ranked B-cell, MHC-I, and MHC-II epitopes of PSA D15 and Cag11 proteins were predicted, screened, and selected. Subsequently, a novel multi-epitope PSA D15 and Cag11 antigens were designed by fused the high-ranked B-cell, MHC-I, and MHC-II epitopes and 50S ribosomal protein L7/L12 adjuvant using linkers. The antigenicity, solubility, physicochemical properties, secondary and tertiary structures, 3D model refinement, and validations were carried. Furthermore, the designed multi-epitope antigens were subjected to codon adaptation and in silico cloning, immune response simulation, and molecular docking with receptor molecules. A novel, stable multi-epitope PSA D15 and Cag11 H. pylori antigens were developed and immune simulation of the designed antigens showed desirable levels of immunological response. Molecular docking of designed antigens with immune receptors (B-cell, MHC-I, MHC-II, and TLR-2/4) revealed robust interactions and stable binding affinity to the receptors. The codon optimized and in silico cloned showed that the designed antigens were successfully expressed (CAI value of 0.95 for PSA D15 and 1.0 for Cag11) after inserted into pET-32ba (+) plasmid of the E. coli K12 strain. In conclusion, this study revealed that the designed multi-epitope antigens have a huge immunological potential candidate biomarker and useful in developing immunodiagnostic assays and vaccines for H. pylori infection.

Precision Colorectal Cancer Fecal Immunological Test Screening With Fecal-Hemoglobin-Concentration-Guided Interscreening Intervals.

Importance: Given a gradient relationship between fecal hemoglobin (f-Hb) concentration and colorectal neoplasia demonstrated previously, using f-Hb-guided interscreening interval has increasingly gained attention in population-based fecal immunological test (FIT), but it is very rare to address how to implement such a precision strategy and whether it can economize the use of FIT and colonoscopy. Objective: To demonstrate the applicability of personalized colorectal cancer (CRC) screening with f-Hb-guided screening intervals to reduce the number of FITs and colonoscopy with as equivalent efficacy as universal biennial screening. Design, Setting, and Participants: A retrospective cohort study for developing f-Hb-guided precision interscreening interval was conducted using data on a Taiwanese biennial nationwide FIT screening program that enrolled more than 3 million participants aged 50 to 74 years between 2004 and 2014. The cohort was followed up over time until 2019 to ascertain colorectal neoplasia and causes of death. A comparative study was further designed to compare the use of FIT and colonoscopy between the personalized f-Hb-guided group and the universal biennial screening group given the equivalent efficacy of reducing CRC-related outcomes. Main Outcomes and Measurements: A spectrum of f-Hb-guided intervals was determined by using the Poisson regression model given the equivalent efficacy of a universal biennial screening. The use of FIT and colonoscopy for the pragmatic f-Hb-guided interval group was measured compared with the universal biennial screening group. Data analysis was performed from September 2022 to October 2023. Results: Using data from the 3 500 250 participants (mean [SD] age, 57.8 [6.0] years) enrolled in the Taiwanese biennial nationwide FIT screening program, an incremental increase in baseline f-Hb associated with colorectal neoplasia and CRC mortality consistently was observed. Participants with different f-Hb levels were classified into distinct risk categories. Various screening intervals by different f-Hb levels were recommended. Using the proposed f-Hb-guided screening intervals, it was found that the personalized method was imputed to reduce the number of FIT tests and colonoscopies by 49% and 28%, respectively, compared with the universal biennial screening. Conclusion and Relevance: The gradient relationship between f-Hb and colorectal neoplasia and CRC mortality was used to develop personalized FIT screening with f-Hb-guided screening intervals. Such a precision interscreening interval led to the reduced use of FIT test and colonoscopy without compromising the effectiveness of universal biennial screening.

Recombinant multiepitope proteins expressed in Escherichia coli cells and their potential for immunodiagnosis.

Recombinant multiepitope proteins (RMPs) are a promising alternative for application in diagnostic tests and, given their wide application in the most diverse diseases, this review article aims to survey the use of these antigens for diagnosis, as well as discuss the main points surrounding these antigens. RMPs usually consisting of linear, immunodominant, and phylogenetically conserved epitopes, has been applied in the experimental diagnosis of various human and animal diseases, such as leishmaniasis, brucellosis, cysticercosis, Chagas disease, hepatitis, leptospirosis, leprosy, filariasis, schistosomiasis, dengue, and COVID-19. The synthetic genes for these epitopes are joined to code a single RMP, either with spacers or fused, with different biochemical properties. The epitopes' high density within the RMPs contributes to a high degree of sensitivity and specificity. The RMPs can also sidestep the need for multiple peptide synthesis or multiple recombinant proteins, reducing costs and enhancing the standardization conditions for immunoassays. Methods such as bioinformatics and circular dichroism have been widely applied in the development of new RMPs, helping to guide their construction and better understand their structure. Several RMPs have been expressed, mainly using the Escherichia coli expression system, highlighting the importance of these cells in the biotechnological field. In fact, technological advances in this area, offering a wide range of different strains to be used, make these cells the most widely used expression platform. RMPs have been experimentally used to diagnose a broad range of illnesses in the laboratory, suggesting they could also be useful for accurate diagnoses commercially. On this point, the RMP method offers a tempting substitute for the production of promising antigens used to assemble commercial diagnostic kits.

The use of peptides for immunodiagnosis of human Chagas disease.

Chagas disease, caused by the protozoa Trypanosoma cruzi, continues to be a serious public health problem in Latin America, worsened by the limitations in its detection. Given the importance of developing new diagnostic methods for this disease, the present review aimed to verify the number of publications dedicated to research on peptides that demonstrate their usefulness in serodiagnosis. To this end, a bibliographic survey was conducted on the PubMed platform using the keyword "peptide" or "epitope" combined with "Chagas disease" or "Trypanosoma cruzi"; "diagno*" or "serodiagnosis" or "immunodiagnosis", without period restriction. An increasing number of publications on studies employing peptides in ELISA and rapid tests assays was verified, which confirms the expansion of research in this field. It is possible to observe that many of the peptides tested so far originate from proteins widely used in the diagnosis of Chagas, and many of them are part of commercial tests developed. In this sense, as expected, promising results were obtained for several peptides when tested in ELISA, as many of them exhibited sensitivity and specificity values above 90%. Furthermore, some peptides have been tested in several studies, confirming their diagnostic potential. Despite the promising results observed, it is possible to emphasize the need for extensive testing of peptides, using different serological panels, in order to confirm their potential. The importance of producing an effective assay capable of detecting the clinical stages of the disease, as well as new immunogenic antigens that enable new serological diagnostic tools for Chagas disease, is evident.

Evaluation of the "Burgenland PREvention trial of colorectal cancer Disease with ImmunologiCal Testing" (B-PREDICT)-a population-based colorectal cancer screening program.

BACKGROUND: The colorectal cancer (CRC) screening program B-PREDICT is a population based invited two stage screening project using a faecal immunochemical test (FIT) for initial screening followed by a colonoscopy for those with a positive FIT. B-PREDICT was compared with the opportunistic screening colonoscopy (OPP-COL), performed in course of the nationwide screening program. METHODS: Within B-PREDICT all residents of the Austrian federal state Burgenland, aged between 40 and 80 are annually invited to FIT testing. All individuals who underwent initial colonoscopy in Burgenland between 01/2003 and 12/2014, were included in this study. Individuals from the FIT-triggered invited screening program B-PREDICT were compared with those from the non-FIT triggered OPP-COL. RESULTS: 15 133 individuals from B-PREDICT were compared to 10 045 individuals with OPP-COL. CRC detection rates were 1.34% (CI-95%, [1.15; 1.52]) in B-PREDICT compared to 0.54% in OPP-COL (95%-CI, [0.39; 0.68] p < 0.001). The decrease in the age standardized incidence rates of CRC was more pronounced in the population screened with FIT than in the general population screened with colonoscopy. Changes in incidence rates per year were -4.4% (95%-CI, [-5.1; -3.7]) vs. -1.8% (95%-CI, [-1.9; -1.6] p < 0.001). CONCLUSIONS: B-PREDICT shows a two-fold higher detection rate of CRC as well as HRA compared to OPP-COL.

Next-Generation Multitarget Stool DNA Test for Colorectal Cancer Screening.

BACKGROUND: A next-generation multitarget stool DNA test, including assessments of DNA molecular markers and hemoglobin level, was developed to improve the performance of colorectal cancer screening, primarily with regard to specificity. METHODS: In a prospective study, we evaluated a next-generation multitarget stool DNA test in asymptomatic adults 40 years of age or older who were undergoing screening colonoscopy. The primary outcomes were sensitivity of the test for colorectal cancer and specificity for advanced neoplasia (colorectal cancer or advanced precancerous lesions). Advanced precancerous lesions included one or more adenomas or sessile serrated lesions measuring at least 1 cm in the longest dimension, lesions with villous histologic features, and high-grade dysplasia. Secondary objectives included the quantification of sensitivity for advanced precancerous lesions and specificity for nonneoplastic findings or negative colonoscopy and comparison of sensitivities for colorectal cancer and advanced precancerous lesions between the multitarget stool DNA test and a commercially available fecal immunochemical test (FIT). RESULTS: Of 20,176 participants, 98 had colorectal cancer, 2144 had advanced precancerous lesions, 6973 had nonadvanced adenomas, and 10,961 had nonneoplastic findings or negative colonoscopy. With the next-generation test, sensitivity for colorectal cancer was 93.9% (95% confidence interval [CI], 87.1 to 97.7), and specificity for advanced neoplasia was 90.6% (95% CI, 90.1 to 91.0). Sensitivity for advanced precancerous lesions was 43.4% (95% CI, 41.3 to 45.6), and specificity for nonneoplastic findings or negative colonoscopy was 92.7% (95% CI, 92.2 to 93.1). With the FIT, sensitivity was 67.3% (95% CI, 57.1 to 76.5) for colorectal cancer and 23.3% (95% CI, 21.5 to 25.2) for advanced precancerous lesions; specificity was 94.8% (95% CI, 94.4 to 95.1) for advanced neoplasia and 95.7% (95% CI, 95.3 to 96.1) for nonneoplastic findings or negative colonoscopy. As compared with FIT, the next-generation test had superior sensitivity for colorectal cancer (P<0.001) and for advanced precancerous lesions (P<0.001) but had lower specificity for advanced neoplasia (P<0.001). No adverse events occurred. CONCLUSIONS: The next-generation multitarget stool DNA test showed higher sensitivity for colorectal cancer and advanced precancerous lesions than FIT but also showed lower specificity. (Funded by Exact Sciences; BLUE-C ClinicalTrials.gov number, NCT04144738.).

Testing for SARS-CoV-2: lessons learned and current use cases.

SUMMARYThe emergence and worldwide dissemination of SARS-CoV-2 required both urgent development of new diagnostic tests and expansion of diagnostic testing capacity on an unprecedented scale. The rapid evolution of technologies that allowed testing to move out of traditional laboratories and into point-of-care testing centers and the home transformed the diagnostic landscape. Four years later, with the end of the formal public health emergency but continued global circulation of the virus, it is important to take a fresh look at available SARS-CoV-2 testing technologies and consider how they should be used going forward. This review considers current use case scenarios for SARS-CoV-2 antigen, nucleic acid amplification, and immunologic tests, incorporating the latest evidence for analytical/clinical performance characteristics and advantages/limitations for each test type to inform current debates about how tests should or should not be used.

Evaluación de pruebas inmunológicas en el diagnóstico de Giardia duodenalis y Cryptosporidium spp, Honduras / Evaluation of immunologic tests in the diagnosis of Giardia duodenalis and Cryptosporidium spp., Honduras

Antecedentes: No conocemos datos sobre evaluación de pruebas inmunológicas para mejorar el diagnóstico de Giardia duodenalis y Cryptosporidium spp., agentes etiológicos de diarrea de importancia mundial, en Honduras. Objetivos: Comparar dos pruebas inmunológicas para el diagnóstico de Giardia y Cryptosporidium spp. con microscopía de rutina y determinar su aplicabilidad local. Métodos: Estudio descriptivo transversal. En 2013, 134 muestras de heces recibidas en el Servicio de Parasitología del Hospital Escuela (HE) y 67 muestras del Centro de Salud Alonso Suazo (CSAS) se analizaron con una Prueba Rápida Inmunocromatográfica (PDR). En 2019-2020, 60 muestras de heces del HE se analizaron con una prueba inmunoenzimática ELISA. El protocolo de rutina incluyó examen directo en solución salina y solución de Lugol, coloración tricrómica y coloración ácido resistente modificada (ARM) (HE) y examen directo en solución salina y solución de Lugol (CSAS). Resultados: Cada prueba inmunológica mostró mayor positividad que la microscopía: en 134 muestras del HE para Giardia (6.7% vs 4.5%) y Cryptosporidium (3.7% vs 0.7%), similar en 67 muestras del CSAS (14.9% vs 7.5% para Giardia; 0.7% para Cryptosporidium con la prueba inmunológica). De 60 muestras analizadas por ELISA en HE, 31.7% fue positiva por Giardia vs 18.3% en examen directo y 23.3% en coloración tricrómica; 6.7% positiva por Cryptosporidium spp. vs 3.3% por coloración ARM. Discusión: Pruebas inmunológicas aumentaron significativamente el diagnóstico de ambas parasitosis; sin embargo, publicaciones sobre pruebas similares ofrecieron resultados no concluyentes. Por costo elevado podrían reservarse para pacientes pediátricos, pacientes inmunocomprometidos en hospitales, complementando microscopía. Los laboratorios de salud deben fortalecer capacidad diagnóstica...(AU)

Implementation of rapid and frequent SARS-CoV2 antigen testing and response in congregate homeless shelters.

BACKGROUND: People experiencing homelessness who live in congregate shelters are at high risk of SARS-CoV2 transmission and severe COVID-19. Current screening and response protocols using rRT-PCR in homeless shelters are expensive, require specialized staff and have delays in returning results and implementing responses. METHODS: We piloted a program to offer frequent, rapid antigen-based tests (BinaxNOW) to residents and staff of congregate-living shelters in San Francisco, California, from January 15th to February 19th, 2021. We used the Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM) framework to evaluate the implementation. RESULTS: Reach: We offered testing at ten of twelve eligible shelters. Shelter residents and staff had variable participation across shelters; approximately half of eligible individuals tested at least once; few tested consistently during the study. Effectiveness: 2.2% of participants tested positive. We identified three outbreaks, but none exceeded 5 cases. All BinaxNOW-positive participants were isolated or left the shelters. Adoption: We offered testing to all eligible participants within weeks of the project's initiation. Implementation: Adaptations made to increase reach and improve consistency were promptly implemented. Maintenance: San Francisco Department of Public Health expanded and maintained testing with minimal support after the end of the pilot. CONCLUSION: Rapid and frequent antigen testing for SARS-CoV2 in homeless shelters is a viable alternative to rRT-PCR testing that can lead to immediate isolation of infectious individuals. Using the RE-AIM framework, we evaluated and adapted interventions to enable the expansion and maintenance of protocols.

Evaluation of urine sample for diagnosis of visceral leishmaniasis using rK-39 immunochromatographic test in Northwest Ethiopia.

BACKGROUND: Visceral leishmaniasis is the most severe form of leishmaniasis which ranks second in mortality and fourth in morbidity. Parasitological diagnostic techniques with splenic aspirate remain the gold standard. However, sample collection is risky, painful, and difficult. Alternatively, serological techniques provide good diagnostic accuracy using serum sample that is difficult for applying on small children and in the field. So, finding alternative non-invasive and self-collected samples like urine is very important. Thus, the study aimed to evaluate the diagnostic performance of the rK-39 strip test using urine for diagnosis of visceral leishmaniasis. METHODS: A multicenter institutional-based cross-sectional study was conducted from November 2019 to March 2021 at Northwest Ethiopia. Sociodemographic information was collected using a structured questionnaire. Blood sample and midstream urine sample were collected for rK-39 test. Data were entered into Epi-data version 4.2 and analyzed using SPSS version 24.0. Diagnostic performance parameters of urine-based rK-39 rapid test, i.e. sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios (LR+/-), and diagnostic accuracy were determined on contingency table by using serum-based rK-39 test result as a reference. An agreement between urine and serum-based rK-39 test was statistically determined by kappa value. RESULT: In total, 300 subjects, age ranged between 7 and 60 years, were included in the study. The overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of urine-based rK-39 test were found to be 98.0% (95% CI: 93.0% - 99.8%), 95.5% (95% CI: 91.6% - 97.9%), 91.6% (95% CI: 85.2%- 95.4%), 98.9 (95% CI: 96.0%- 99.7%), and 96.33% (95% CI: 93.53-98.16%), respectively. Additionally, there was a strong agreement between the results obtained on rK-39 ICT using urine and serum samples (kappa = 0.92; P < 0.001). CONCLUSION: Urine-based rK-39 ICT had an excellent high sensitivity, specificity and strong agreement with serum-based rK-39 ICT results. This indicates that urine sample would be a promising noninvasive and easy to collect sample for diagnosis of VL in field and rural settings.

CXCL13 in laboratory diagnosis of Lyme neuroborreliosis-the performance of the recomBead and ReaScan CXCL13 assays in human cerebrospinal fluid samples.

The chemokine CXCL13 is used as complement to serology in the diagnostics of Lyme neuroborreliosis (LNB). We evaluated and compared the semi-quantitative, cassette-based ReaScan CXCL13 assay with the quantitative recomBead CXCL13 assay using a collection of 209 cerebrospinal fluid samples. The categorical agreement between results interpreted as negative, grey zone, and positive by the two methods was 87%. The diagnostic sensitivity was higher using the recomBead assay, whereas specificity was higher using ReaScan. Few manual steps, and a short turn-around time with no batching of samples makes the ReaScan CXCL13 assay an attractive complement to serology in the diagnostics of LNB.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Accompanied by IgG4-Tubulointerstitial Nephritis with Underlying Sjögren Syndrome: A Case Report and Review of Literature.

OBJECTIVE: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of autoimmune multisystemic diseases characterized by necrotizing inflammation of small vessels and the presence of circulating ANCA. The prevalence of overlap AAV with other autoimmune diseases was low. CASE REPORT: We report a case of a 54-year-old woman who presented with a 20-year-history of sicca symptoms, the presence of anti-Ro/SS-A, anti-La/SS-B antibodies, myeloperoxidase -ANCA (MPO-ANCA), significant increase of serum IgG4 level, microscopic hematuria, non-nephrotic proteinuria, and progressive renal dysfunction. A renal biopsy showed pauci-immune necrotizing glomerulonephritis with crescents with severe tubulointerstitial nephritis (TIN) which shows extensive infiltration of IgG4-positive plasma cells. Considering these findings and the clinical course, the disease was considered more likely to be MPO-ANCA-associated vasculitis accompanied by IgG4-TIN with underlying primary Sjögren syndrome (pSS). CONCLUSION: This report shows a possible unusual disease overlap of MPO-ANCA-associated vasculitis and IgG4-TIN with underlying pSS.

Lateral flow devices for samples collected by straw sampling method for postmortem canine rabies diagnosis.

The direct fluorescent antibody test (dFAT) using brain sample after opening the skull is the standard rabies diagnostic test in animal rabies. However, it is not feasible in many resource-limited settings. Lateral flow devices (LFD) combined with a simple sampling methodology is quicker, simpler, and less hazardous than the standard test and can be a useful tool. We conducted a prospective on-site study to evaluate the diagnostic accuracy of the LFD with the straw sampling method compared with that of the dFAT with the skull opening procedure for post-mortem canine rabies diagnosis. We collected 97 rabies-suspected animals between December 1, 2020 and March 31, 2021. Among the 97 samples, 53 and 50 cases were positive tests for dFAT and LFD, respectively. The sensitivity and specificity of LFD with straw sampling method were 94.3% (95% confidence interval [CI], 84.3-98.8%) and 100% (95% CI, 92.0-100%), respectively. The performance of LFD by the straw sampling method showed relatively high sensitivity and 100% specificity compared with that of dFAT performed on samples collected after opening the skull. This methodology can be beneficial and is a strong tool to overcome limited animal surveillance in remote areas. However, because of our limited sample size, more data using fresh samples on-site and the optimizations are urgently needed for the further implementation in endemic areas.

Liquiritigenin enhances cyclic adenosine monophosphate production to mitigate inflammation in dendritic cells.

OBJECTIVE: This study aims to dissect the mechanism of traditional Chinese medicinal herbs against asthma; we chose to first focus on the main chemical components of licorice to investigate their contribution to asthmatic inflammation inhibition. METHODS: Production of cellular nucleotide molecules such as cAMP, cGMP, and cGAMP was examined by using enzyme-linked immunosorbent assay (ELISA). Enzyme-encoding genes were tested in vitro using quantitative real-time PCR and protein level was detected by Western blotting analysis. In addition, co-culturing of murine dendritic cells together with T cells was conducted to examine the expression of cytokine genes and host immune response. RESULTS: We found that one of the components within licorice, named liquiritigenin (LR), could efficiently enhance cAMP production in different cell lines. The augmentation of such molecules was linked to the high expression of cAMP synthesis genes and repressed expression of cAMP breaking down genes. In addition, the downstream immune response was also alleviated by the increase in cAMP levels by LR, suggesting the great potential of this molecule against inflammation. Subsequent immunological tests showed that LR could efficiently inhibit the expression of several cytokines and alter the NF-κB pathway and T cell polarization. CONCLUSION: Altogether, we have identified a promising antiasthmatic agent LR that could exhibit immunosuppressive function by elevating the cAMP level.

Role of tumor necrosis factor-α in the mortality of hospitalized patients with severe and critical COVID-19 pneumonia.

The coronavirus disease 2019 (COVID-19) is presently the most pressing public health concern worldwide. Cytokine storm is an important factor leading to death of patients with COVID-19. This study aims to characterize serum cytokines of patients with severe or critical COVID-19. Clinical records were obtained from 149 patients who were tested at the Sino-French New City Branch of Tongji Hospital from 30 January to 30 March 2020. Data regarding the clinical features of the patients was collected and analyzed. Among the 149, 45 (30.2%) of them had severe conditions and 104 (69.8%) of that presented critical symptoms. In the meantime, 80 (53.7%) of that 149 died during hospitalization. Of all, male patients accounted for 94 (69.1%). Compared with patients in severe COVID-19, those who in critical COVID-19 had significantly higher levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8, and IL-10. Moreover, the passed-away patients had considerably higher levels of TNF-α, IL-6, IL-8, and IL-10 than those survived from it. Regression analysis revealed that serum TNF-α level was an independent risk factor for the death of patient with severe conditions. Among the proinflammatory cytokines (IL-1ß, TNF-α, IL-8, and IL-6) analyzed herein, TNF-α was seen as a risk factor for the death of patients with severe or critical COVID-19. This study suggests that anti-TNF-α treatment allows patients with severe or critical COVID-19 pneumonia to recover.

Natural Anti-Endothelial Cell Antibodies in Patients Undergoing Coronary Angiography.

BACKGROUND: Anti-endothelial cell antibodies (AECA) are a known biomarker of endothelial dysfunction and damage in clinical practice, especially in autoimmune disease. OBJECTIVES: To determine the relation between natural AECA levels and prognosis related to coronary artery disease. METHODS: Candidates for coronary angiography were prospectively enrolled. AECA levels were determined by ELISA assay. Mortality was evaluated after more than 5 years follow-up. RESULTS: Of a total 857 patients, 445 had high AECA levels (group 1) and 412 had low levels (< 1 OD unit, group 2). Both groups did not differ in age, sex, or presence of diabetes. The median follow up was 2293 days (76 months). Patients with high AECA levels were more likely to have normal coronary arteries on angiography (21.6% vs. 16.9%, P = 0.047) and less likely to have calcified lesions (19.0% vs. 26.6%, P = 0.028) and lower prevalence of abnormal renal functions (71.1 mg/dl vs. 66.5 mg/dl, P = 0.033). Patients with higher AECA levels had lower mortality levels (20.1% vs. 27.6%, P = 0.006). A logistic regression model demonstrated independent association between lower AECA levels and the presence of coronary atherosclerosis based on angiogram. CONCLUSIONS: After a median of more than 6 years, higher natural AECA levels were associated with less coronary artery disease and lower mortality rates in patients undergoing coronary angiography.