Alpha-defensins Research Articles

Role of Salivary Physicochemical and Peptide Levels in Dental Caries among Children: An Original Research.

Introduction:Dental caries is a common oral disease that still needs to be thoroughly evaluated for understanding the pathophysiology. Hence, in our study, we evaluate the physicochemical and the peptide properties of the saliva and their role in dental caries among children.Materials and Methods:We conducted an observational in vitro study among 100 subjects of age 5–15 years. Decayed, missing, and filled surface (DMFT)/dmft was used to calculate the caries activity. The unstimulated saliva was evaluated for the peptides “LL-37, human neutrophil peptide (HNP) 1-3, and human beta-defensin-3” by ELIZA and for the “pH, buffer, and flow rate” of the saliva. The data thus obtained were analyzed to correlate caries and the salivary physiochemical and peptides using the “linear regression analysis.” P < 0.05 was deliberated as significant.Results:Although no statistically significant variation was seen between low and high caries risk groups and the salivary parameters in our study, we observed a negative correlation of the salivary peptides and caries. For the salivary peptide “HNP1-3,” there was a statistically significant variation.Conclusion:The salivary peptides may be carioprotective. However, further research has to be done to establish the mechanism of the action of these substances against caries.

CONTROLLING THE EXPRESSION LEVEL OF ALPHA-DEFENSINS BY LOW MOLECULAR WEIGHT BIOREGULATORS

Human alpha defensins (Human neutrophil peptides 1-3, HNP1-3) are constitutively produced by immunocompetent cells and protect against pathogenic bacteria. The effect of low molecular weight bioregulators catecholamine norepinephrine and muramyl peptide on the expression of HNP1-3 was studied. It has been shown that muramylpeptide restores the level of alpha-defensins HNP1-3 produced by human neutrophils in vitro, reduced by the action of catecholamine norepinephrine.

Aptamer selection against alpha-defensin human neutrophil peptide 1 on an integrated microfluidic system for diagnosis of periprosthetic joint infections.

Periprosthetic joint infections (PJIs) arising from joint arthroplasty are dreadful, yet difficult to diagnose in subtle cases. Definite diagnosis requires microbiological culture to confirm the causative pathogens. However, up to 40% of culture-negative PJI needs other surrogate biomarkers such as human neutrophil peptide 1 (HNP 1) to improve diagnostic accuracy or gauge therapeutic responses. To devise a diagnostic method, systematic evolution of ligands by exponential enrichment (SELEX) (five rounds) was used to screen PJI biomarkers on a compact (20 × 20 × 35 cm), integrated microfluidic system equipped with two separate Peltier devices and one magnetic control module where an aptamer with high affinity and specificity for HNP 1, which has been used as one of the synovial fluid (SF) biomarkers for detecting PJI, was identified for the first time. Two rounds of negative selection (with immunoglobulin G & human serum album) on-chip followed by one round of unique "competitive selection" with SF extracted from PJI patients validated the specificity of the HNP 1 aptamer. The dissociation constant was measured to be 19 nM. The applicability of SF HNP 1 levels for diagnosing PJI was then verified by a new aptamer-based enzyme-linked immunosorbent assay (ELISA)-like assay. It is envisioned that this new aptamer and the associated assay could be used in future clinical applications.

The role of human alpha defensin 5 and secretory Immunoglobulin A in local immunity in children with rotavirus infection

The role of human alpha defensin 5 and secretory Immunoglobulin A in local immunity in children with rotavirus infection

Atrial Fibrillation Recurrence Following Cardioversion: The Predictive Value of Alpha Defensin

Atrial Fibrillation Recurrence Following Cardioversion: The Predictive Value of Alpha Defensin

High level of defensin alpha 5 in intestine may explain the low incidence of diarrhoea in COVID-19 patients.

High level of defensin alpha 5 in intestine may explain the low incidence of diarrhoea in COVID-19 patients.

Human neutrophil peptide 1 promotes immune sterilization in vivo by reducing the virulence of multidrug-resistant Klebsiella pneumoniae and increasing the ability of macrophages.

By studying the expression in patients and cell modeling in vitro, antimicrobial peptides for Klebsiella were screened. Killing curve and membrane permeability experiments are used to study the antibacterial effect of antimicrobial peptides in vitro. Cytotoxicity-related indicators including lipopolysaccharide (LPS), capsule polysaccharide (CPS), and outer membrane protein expression were measured. Intranasal inoculation of pneumoconiosis was used to construct a mouse infection model, and the survival rate and cytokine expression level were tested. Human neutrophil peptide 1 (HNP-1) showed a significant antibacterial effect, which improved the permeability of the outer membrane of K. pneumoniae. Moreover, HNP-1 decreased LPS, CPS content, and outer membrane proteins. K. pneumoniae infection decreased antimicrobial peptide, oxidative stress, and autophagy-related genes, while HNP-1 increased these genes. After coculture with macrophages, the endocytosis of macrophages is enhanced and the bacterial load is greater in the K. pneumoniae + peptide group. Besides, higher levels of pp38 and pp65 in the K. pneumoniae + peptide group. HNP-1 rescued the cytotoxicity induced by K. pneumoniae. The survival rate is significantly improved after K. pneumoniae is treated by HNP-1. All cytokines in the peptide group were significantly higher. HNP-1 promotes immune sterilization by reducing the virulence of multidrug-resistant K. pneumoniae and increasing the ability of macrophages.

Which International Consensus Meeting Preoperative Minor Criteria is the Most Accurate Marker for the Diagnosis of Periprosthetic Joint Infection in Hip and Knee Arthroplasty?

The accurate preoperative diagnosis of periprosthetic joint infection (PJI) is critical. The aim of this study was to evaluate the diagnostic accuracy and performance of the 2018 International Consensus Meeting (ICM) preoperative minor criteria for the diagnosis of chronic PJI in total hip and knee arthroplasty. We retrospectively reviewed 260 patients that underwent a revision knee or hip arthroplasty at our institution between 2015 and 2017. All major and minor 2018 ICM criteria (except erythrocyte sedimentation rate, D-dimer) were available for all patients included. Cases with at least 1 major criterion were considered as infected. Receiver operative characteristic curve analysis was performed for preoperative minor criteria. The diagnostic performance of the preoperative minor criteria ranked as per the area under the curve was PMN% (0.926), alpha defensin (0.922), white blood cell count (0.916), leukocyte esterase (0.861), and serum C-reactive protein (0.860). Increasing the PMN % cutoff from 70% to 77.8% improves the diagnostic accuracy (86.5% vs 90.8%). The highest diagnostic performance was achieved by combining all 5 preoperative parameters, and at current ICM thresholds, the diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive were 93.5%, 95.4%, 92.1%, 89.7%, and 96.5%, respectively. The diagnostic performance of preoperative minor criteria was outstanding (PMN%, alpha defensin, white blood cell count) or excellent (leukocyte esterase, serum C-reactive protein). PMN% showed the best diagnostic utility (area under the curve) and should have an increased weight-adjusted score in the ICM scoring system.

The utility of human neutrophil peptide (1–3) in upper and lower pediatric urinary tract infections in kerbala province

Human Neutrophil Peptide is important components of the innate defense mechanism in the urinary tract. This aim was investigated by comparing urinary HNP (1–3) peptide levels of upper and lower Urinary tract infections (UTIs) patients to those of controls. A case- control study was conducted in Kerbala teaching Hospital during the period from December 2020 to April 2021. Fifty patients with confirmed pyelonephritis or cystitis and 40 healthy controls without UTI. Urinary level of HNP (1–3) were determined using an Enzyme linked immunosorbent assay (ELISA) kit. The mean concentration of anti-microbial peptide HNP (1–3) ng/ml was 5.8988 ng/ml in pyelonephritis patients compared with cystitis patients 5.1203 ng/ml, while the concentration in patients generally was 5.385 ng/ml compared with heathy control where it was 0.9047.

The alpha defensin lateral flow test is effective in predicting eradication of periprosthetic joint infection after surgical debridement

The primary aim of this study was to assess the utility of the alpha defensin lateral flow (ADLF) test for predicting the eradication of PJI after surgical debridement. The secondary aim was to describe the reliability of ADLF test in diagnosis of PJI intra- operatively. A prospective observational study was conducted in three independent orthopaedic centres. Twenty-two patients undergoing revision surgery (debridement, antibiotics and implant retention (DAIR), single or two-stage revision) for PJI were recruited, 13 female and 9 male with an average age of 64 years. Samples were collected intra-operatively at the start of the first surgical procedure and then at the completion of debridement or prior to reimplantation depending on the operation performed. These samples were tested using ADLF and then sent for microbiological analysis. The ADLF result was then compared to the corresponding culture result in order to determine the diagnostic predictive accuracy. The reliability of ADLF test to predict eradication of infection after debridement of PJI was excellent for specificity and positive predictive value (PPV) of which both where 100%, but had a poor sensitivity (14.3%) and negative predictive value (NPV) (62.5%). The reliability of ADLF test to predict PJI was poor with only a 50% sensitivity and specificity. The ADLF test has a high specificity and PPV for diagnosing eradication of infection after debridement. In contrast the ADLF testing appears to have poor diagnostic accuracy for PJI when used on intra-operative samples, prior to surgical intervention.

Human α-defensin 5 suppressed colon cancer growth by targeting PI3K pathway

Defensins are highly conserved antimicrobial peptides, which ubiquitously expressed in different species. In addition to the functions in host defense, their aberrant expression have also been documented in cancerous tissue including breast cancer, lung caner and renal carcinoma etc. Whereas, roles of Defensin Alpha 5 (DEFA5) in colon cancer has not been explored. Bioinformatic analysis was used to study the expression of DEFA5 and its correlation with clinical outcomes; Western blot, qPCR, Co-immunoprecipitation, xenograft models were used to the study the molecular mechanism. Decreased expression of DEFA5 at protein level was observed in colon tissues. Colon cancer cell lines proliferation and colony formation capacity were significantly suppressed by DEFA5 overexpression. Moreover, in vivo tumor growth in nude mice was also suppressed by DEFA5 overexpression, suggesting a tumor suppressor role of DEFA5 in colon cancer. Mechanistically, DEFA5 directly binds to the subunits of PI3K complex, thus attenuates the downstream signaling transduction, leads to delayed cell growth and metastasis. Collectively, we concluded that DEFA5 showed an inhibitory effect in colon cancer cell growth and may serve as a potential tumor suppressor in colon cancer.

Preclinical Safety Evaluation of a Recombinant Plasmid Vector Encoding Mature Human Neutrophil Peptide-1 by Repeated Local Administrations in Nonhuman Primates.

In our previous studies, a novel gene therapy approach was developed based on a plasmid vector pSecTag2B in which recombinant HNP1 gene was regulated under a cytomegalovirus promoter to encode a mature human neutrophil peptide-1 (HNP1) form. We showed for the first time in various tumor models, including human cancer xenografts, that overexpression of HNP1 in the tumor milieu by intratumoral pSecTag-HNP1 (pHNP1) administration efficiently attenuated in vivo tumor progression, mediated host immune responses to tumors, and produced a synergistic effect when combined with chemotherapeutics. In this study, a preclinical safety investigation of HNP1 gene therapy was conducted in nonhuman primates. Eleven cynomolgus monkeys were divided into three groups of three to four animals each and received either repeated s.c. injections of pHNP1/cationic liposome complexes at a low (0.625 mg/kg) or a high (2.5 mg/kg) dose or glucose as control. Significant HNP1 in vivo accumulation was detected after consecutive administrations. All primates reached the end of the study with good body conditions. Injection site inflammation was the only obvious toxic reaction during observation period. In addition, elevation of monocyte/macrophage and neutrophil as well as decline of lymphocyte were detected in the peripheral blood of pHNP1-treated primates. These alterations were partially alleviated at the end of observation period. Besides, dose-related histopathological changes of the immune organs were observed at necropsy, including a minimal thymic lymphocyte decrease and a minimal-to-mild lymph node erythrocyte increase, but which cannot be excluded from HNP1-induced immune reactions. Together, these data support future clinical studies of pHNP1-based local gene delivery in tumor patients.

Metaproteomics associated with severe early childhood caries highlights the differences in salivary proteins

ObjectiveTo investigate the salivary metaproteomic characteristics of the children with and without severe early childhood caries (S-ECC). DesignIn this study, we collected unstimulated saliva samples from 34 children (age 3–4 years) with caries free (NC, dmfs (= index of decayed, missing due to caries, or filled tooth surfaces) = 0, n = 23) and with S-ECC (dmfs≥10, n = 11). Salivary proteins were extracted and reduced, and then a Liquid Chromatography/Mass Spectrometry system was used to identify proteins. ResultsNearly 3000 proteins were identified in this study, and about 3.5 % of the proteins originated from human while 86 % were derived from microbes. The salivary protein types in the NC group were statistically greater than those in the S-ECC group (P <0.05). Specifically, the salivary protein types derived from microbes in the NC group were significantly greater than those in the S-ECC group. Three proteins, human lactoferrin, penicillin-binding protein 1C [Burkholderia ubonensis], human alpha-defensin 1 (F28a mutant), were decreased statistically in the NC group compared to the S-ECC group (P < 0.05). Only one protein, 50S ribosomal protein L17 secreted by Haemophilus haemolyticus, was significantly increased in the NC group compared to the S-ECC group. Salivary IgA was the top highest protein in the NC group whereas human lysozyme was the top highest protein in the S-ECC group. ConclusionsThe differential proteins recognized in this study may be conducive for finding a caries biomarker. Understanding the metaproteomic characteristics can help us to control the caries from human origin and microbial origin.

Diagnostic values of HNP 1-3 and procalcitonin levels in synovial fluid aspirates in the differential diagnosis between septic arthritis and noninfectious arthritis

IntroductionAlthough early diagnosis of septic arthritis may reduce mortality rates, and limit unnecessary surgical interventions, clinical parameters alone are not adequate for making the diagnosis of septic arthritis. Therefore, relevant laboratory parameters are used to enhance diagnostic sensitivity. The aim of our study was to assist in making the diagnosis of septic arthritis, and prevent delays in the diagnosis. For this purpose; we aimed to determine the diagnostic values of human neutrophil peptides 1-3 (HNP 1-3) and procalcitonin (PCT) in synovial fluids of patients with arthritis. By comparing the HNP 1-3 and procalcitonin levels, as well as CRP, in synovial fluid aspirates, we evaluated the significance of these data in the differential diagnosis of septic arthritis from noninfectious arthritis. MethodsA total of 67 adults consisting of 37 septic arthritis and 30 noninfectious arthritis patients were included in our study. As bioindicators; levels of HNP 1-3, PCT, synovial and serum CRP levels were found to have significant ROC areas in discriminating septic arthritis patients from noninfectious arthritis patients. ResultsAs a result, synovial fluid HNP 1-3 levels were significantly higher in septic arthritis patients compared to noninfectious arthritis patients (p < 0.001). The sensitivity, specificity, and accuracy of HNP 1-3 levels in the diagnosis of septic and noninfectious arthritis were found as 86%, 87%, and 87%, respectively (AUC of the ROC curve = 0.828). ConclusionsIt was decided that the level of HNP 1-3 in the synovial fluid can be used as an alternative indicator in the diagnosis of septic arthritis.

Role of antimicrobial peptides system in inflammatory periodontal diseases non-specific oral cavity protection.

The system of antimicrobial peptides (AMP) is one of the most ancient mechanisms of the macroorganism resistance to infectious pathogens invasion. The aim of the study was to determine the role of the antimicrobial peptides system and periodontal pathogenic markers in the development and progression of inflammatory periodontal diseases. Gingival pocket washes (91 samples in total) for the research were received from patients with inflammatory periodontal diseases (chronic periodontitis and gingivitis) and intact periodontium. Using ELISA, the content of antimicrobial peptides was determined: human alpha-defensin (HNP 1-3), beta-defensin (HBD 1-3) and cathelicidin (LL-37). Periodontal pathogenic markers were isolated during RT-PCR. The study revealed differences in AMP concentrations by groups: level of HBD 2 in patients with chronic periodontitis was 1,36 times higher than those in the group of patients with chronic gingivitis (p=0,023) and 2,39 times higher than those in the control group (p<0,001), the content of HNP 1-3 in the group of patients with chronic periodontitis was reduced by 1,23 times compared with the indicators of the group of patients with gingivitis (p=0,045) and by 1,97 times compared with the indicators of the control group (p<0,001). The frequency of detection of periodontal pathogenic bacteria genes was 88,0% in patients with periodontitis, 76,92% in patients with gingivitis and 33,3% in the group with intact periodontium. HBD 2 content moderately correlated with the definition of P. gingivalis (r=0,612; p=0,022), T. forsythensis (r= 0,434; p=0,015), A. actinomycetemcomitans (r=0,483; p=0,006), a moderate negative correlation was detected between the content of HNP 1-3 and the release of periodontal pathogens in associations (P. gingivalis with T. forsythensis and T. denticola) (r=-0,388; p=0,031) in the group of patients with chronic periodontitis. Thus, the revealed relationships and correlations indicate shifts in the processes of reparative regeneration of the oral cavity and the regulation of local immunity in response to microbial invasion.

Human Defensins Inhibit SARS-CoV-2 Infection by Blocking Viral Entry.

Innate immunity during acute infection plays a critical role in the disease severity of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and is likely to contribute to COVID-19 disease outcomes. Defensins are highly abundant innate immune factors in neutrophils and epithelial cells, including intestinal Paneth cells, and exhibit antimicrobial and immune-modulatory activities. In this study, we investigated the effects of human α- and β-defensins and RC101, a θ-defensin analog, on SARS-CoV-2 infection. We found that human neutrophil peptides (HNPs) 1–3, human defensin (HD) 5 and RC101 exhibited potent antiviral activity against pseudotyped viruses expressing SARS-CoV-2 spike proteins. HNP4 and HD6 had weak anti-SARS-CoV-2 activity, whereas human β-defensins (HBD2, HBD5 and HBD6) had no effect. HNP1, HD5 and RC101 also inhibited infection by replication-competent SARS-CoV-2 viruses and SARS-CoV-2 variants. Pretreatment of cells with HNP1, HD5 or RC101 provided some protection against viral infection. These defensins did not have an effect when provided post-infection, indicating their effect was directed towards viral entry. Indeed, HNP1 inhibited viral fusion but not the binding of the spike receptor-binding domain to hACE2. The anti-SARS-CoV-2 effect of defensins was influenced by the structure of the peptides, as linear unstructured forms of HNP1 and HD5 lost their antiviral function. Pro-HD5, the precursor of HD5, did not block infection by SARS-CoV-2. High virus titers overcame the effect of low levels of HNP1, indicating that defensins act on the virion. HNP1, HD5 and RC101 also blocked viral infection of intestinal and lung epithelial cells. The protective effects of defensins reported here suggest that they may be useful additives to the antivirus arsenal and should be thoroughly studied.

English

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is seen worldwide and is the most common liver disorder in industrialized countries. Non-alcoholic steatohepatitis (NASH) is the severest form of NAFLD and is associated with inflammation and oxidative stress. Human neutrophil peptides have the ability to enhance hepatic fibrosis. We wanted to study the association between neutrophil to lymphocyte ratio and steatohepatitis and fibrosis in patients with non-alcoholic fatty liver disease. METHODS This is an analytical cross-sectional study conducted among 50 cases and 50 controls attending the hospital attached to BMCRI. The neutrophil lymphocyte ratio was calculated and compared between cases and controls. RESULTS Our study results showed that 7 patients had grade 1, 19 had grade 2, 24 had grade 3 hepatic steatosis and 13 patients had fibrosis. The mean neutrophil lymphocyte ratio (NLR) was significantly higher in cases than controls (3.6 +/- 1.83 and 1.72 +/- 0.57, P - 0.00). However, there was no statistical significance (F: 2.06, P value: 0.14) in the utility of NLR in detecting higher grades of steatosis (grade 1:2.41 +/- 0.76, grade 2:4.01 +/- 2.46, grade 3:3.62 +/- 1.3). The mean NLR was significantly higher (P - 0.001) in patients with fibrosis (3.72 +/- 2.1) compared with controls (1.46 +/- 051). CONCLUSIONS The neutrophil lymphocyte ratio can be used to detect the presence of steatohepatitis and fibrosis in patients with NAFLD but cannot be used to predict the presence of higher grades of hepatic steatosis. KEY WORDS Non-Alcoholic Fatty Liver Disease, Non-Alcoholic Steatohepatitis, Fibrosis, Neutrophil-Lymphocyte Ratio

Plasma elafin, cathelicidin, and α-defensins are increased in paediatric inflammatory Crohn's disease and reflect disease location.

IntroductionThe aim of our study was to assess antimicrobial peptides in children with Crohn’s disease (CD).MethodsPlasma elafin, cathelicidin, and α- and β-defensins were assessed in 35 children with CD using immunoassays. Phenotype and location of CD were assessed based on the results of endoscopic and radiological studies.ResultsWe found increased elafin, cathelicidin, and α-defensins in children with inflammatory phenotype as compared to stricturing and penetrating phenotypes of CD. Additionally, we found increased elafin and cathelicidin in colonic location and α-defensins in ileal CD locations.ConclusionsAssessing antimicrobial peptides may be helpful in estimating of phenotype and location of CD lesions.

P071 Crohn’s Disease is associated with elevated levels of the pro-inflammatory CXCR3 ligands (CXCL9, 10 and 11) with an associated reduction in Paneth cell derived antimicrobial peptides in ex-vivo ileal biopsies

Abstract Background Despite an expanding array of treatment options, a significant proportion of patients with Crohn’s Disease (CD) fail to respond to currently available therapies, underpinning the importance of biological insights into disease pathogenesis. The pro-inflammatory chemokines CXCL9,10 and 11 bind to the CXCR3 receptor, highly expressed on effector T-cells. Mouse models of chronic ileitis have shown that CXCR3+ effector T cells drive the loss of paneth cells that play an important role in innate immunity and mucosal barrier function. In the TNFΔΔARE mouse ileitis-model, small molecule inhibition of the CXCR3 receptor reverses paneth cell loss and restores antimicrobial peptide levels. The aims of this study were to evaluate the role of chemokines that bind to CXCR3+ effector T-cells in adult patients with ileal CD compared to healthy controls and to assess the impact of these pro-inflammatory chemokines on paneth cell derived anti-microbial peptides. Methods, 13 CD patients and 16 healthy controls attending for routine endoscopic evaluation were prospectively recruited at St.Vincent’s University Hospital, Dublin and ileal biopsies were collected in media. RNA was isolated from homogenised ileal biopsies (Quiagen kit), DNAse treated using DNAse I (Invitrogen) and reverse transcribed using M-MLV reverse transcriptase (Promega). Target cDNAs were quantified using an Applied BiosystemsTM QuantStudioTM 7 Flex Real-Time PCR System. Results We identified an increase in the relative mRNA expression of CXCR3 associated chemokines, with significantly higher levels of CXCL9, CXCL10 and CXCL11 in ileal CD patients compared to healthy controls. This coincides with a reduction in paneth cell-derived antimicrobial peptides with significantly lower levels of alpha defensins (DEFA5, DEFA6) and lysozyme in CD patients compared to healthy controls. Conclusion This study supports data from animal models and provides a hypothesis for the loss of paneth cells in patients with ileal CD. The reduction in paneth cell derived anti-microbial peptides may help to explain the altered microbiome and provide an explanation for the loss of mucosal barrier integrity in Inflammatory Bowel Disease (IBD). A greater understanding of the role of chemokines in the development of mucosal immunity and inflammation in IBD may allow the targeting of chemokines in novel therapeutic strategies.

Accuracy and Cost-Effectivenss of a Novel Method for Alpha Defensins Measurement in the Diagnosis of Periprosthetic Joint Infections

BackgroundTwo methods for detecting synovial fluids alpha defensins are available: the enzyme-linked immunosorbent assay and the lateral flow test. For both, the proper role and accuracy remain uncertain. The purpose of this study was to assess the accuracy of the matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) for alpha defensin detection in synovial fluids of patients with total knee arthroplasty/total hip arthroplasty failures. The hypothesis was that the alpha defensin measurement through MALDI-TOF MS assay could be a high sensitive and specific test for periprosthetic joint infections (PJI) diagnosis as compared with Musculoskeletal Infection Society (MSIS) criteria. MethodsThe study included 138 patients. The 2018 MSIS criteria were used to diagnose PJIs. Synovial fluids were assessed for routinely synovial fluid tests and alpha defensin measurement through MALDI-TOF MS. Sensitivity, specificity, overall diagnostic accuracy, positive and negative predictive values, receiver operator curves, and area under the curve were calculated. ResultsAs per the 2018 MSIS criteria, 59 PJIs (43%) and 79 aseptic failures (57%) were diagnosed. The MALDI-TOF MS assay showed an overall accuracy of 94.9%. The sensitivity was 93%, the specificity was 96%, the positive predictive value was 95%, and the negative predictive value was 95%. Receiver operator curves analysis demonstrates an area under the curve of 0.95 (P < .001). ConclusionThe MALDI-TOF MS assay showed high sensitivity and specificity for alpha defensin detection in case of total knee arthroplasty/total hip arthroplasty failures. The advantages of the technology, such as the few milliliters of sample needed, the rapidity of obtaining results, and the cost-effectiveness of the procedure could make the MALDI-TOF MS alpha defensin assay a useful and widespread test in clinical practice.