Defensin-A

Background: Alpha-defensin, a novel biomarker, has shown great potential for the accurate diagnosis of periprosthetic joint infection (PJI) in recent years: many published studies have presented encouraging results. Nevertheless, the diagnostic accuracy of alpha-defensin is inconsistent across published studies. Moreover, the optimum value of the diagnostic threshold urgently needs to be ascertained. This meta-analysis sought to estimate the precision of alpha-defensin for the diagnosis of PJI and, where possible, to confirm the threshold. Method: We systematically searched PubMed, Embase, Cochrane, Web of Knowledge, and ClinicalTrials.gov for relevant literature on alpha-defensin in the diagnosis of PJI (searching publications from the inception of each database until February 2017, with no language restriction). Pooled sensitivity, specificity, diagnostic odds ratios, and likelihood ratios were the indexes used for assessment, with the use of a random-effects model. Result: Eleven of the 426 studies that evaluated the diagnostic accuracy of alpha-defensin in periprosthetic joint infection (PJI) were included in this analysis. The pooled diagnostic sensitivity of alpha-defensin for PJI was 0.96 (95% confidence interval [CI], 0.87 to 0.99) and the specificity was 0.95 (95% CI, 0.91 to 0.97). Since there was substantial heterogeneity among studies, based on the inconsistency index (I2), threshold, site of arthroplasty, study design and techniques for the alpha-defensin test, subgroup analyses were performed to estimate the impacts of these variables on heterogeneity. Conclusion: In summary, this meta-analysis clearly lends support to the conclusion that alpha-defensin is a promising addition to the current methods for diagnosis of PJI.

Background: The purpose of this study was to evaluate the alpha defensin qualitative detection (ADLF) sensitivity and specificity as compared with 3 standard classifications in the diagnostic management of chronic prosthetic joint infections. Materials and methods: A multicenter cohort of 136 patients with a painful arthroplasty was classified into either infected or noninfected according to the Musculoskeletal Infection Society (MSIS) score, Infectious Diseases Society of America (IDSA) score, European Bone and Joint Infection Society (EBJIS) score. The sensitivity and specificity of the ADLF test were calculated for each score. Spearman's correlations between all scores were then analyzed, and multiple logistic regression was applied to identify independent variables strongly connected to the prosthetic joint infection probability. Results: The EBJIS score was positive in 68 patients, IDSA score in 50 patients, MSIS score in 41 patients, and ADLF in 40 patients. The ADLF sensitivity was 87.8% compared with MSIS, 70% compared with IDSA, and 55.8% compared with EBJIS. The ADLF specificity was in the range of 94%-97%. A good correlation was observed between synovial fluid cultures and ADLF (r = 0.73). Low to excellent correlations were recorded between ADLF and the EBJIS (r = 0.58), IDSA (r = 0.68), and MSIS (r = 0.84) scores. The synovial fluid's white blood cell count was proven to be the biological test that most influenced the probability of a positive culture (P value: .005). Discussion: The ADLF sensitivity was variable, whereas its specificity was excellent. The EBJIS score results significantly differed from those obtained via cultures, which possibly explains the ADLF low sensitivity compared with that of the EBJIS score.

Introduction: It is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission. These interactions constitute a very complex system of highly regulated pathways known as the innate immune system of the mosquito, which produces antimicrobial peptides that act as effector molecules against bacterial and fungal infections. There is less information about such effects on virus infections. Objective: To determine the expression of two antimicrobial peptide genes, defensin A and cecropin A, in Aedes aegypti mosquitoes infected with DENV-1. Materials and methods: We used the F1 generation of mosquitoes orally infected with DENV-1 and real-time PCR analysis to determine whether the defensin A and cecropin A genes played a role in controlling DENV-1 replication in Ae. aegypti. As a reference, we conducted similar experiments with the bacteria Escherichia coli. Results: Basal levels of defensin A and cecropin A mRNA were expressed in uninfected mosquitoes at different times post-blood feeding. The infected mosquitoes experienced reduced expression of these mRNA by at least eightfold when compared to uninfected control mosquitoes at all times post-infection. In contrast with the behavior of DENV-1, results showed that bacterial infection produced up-regulation of defensin and cecropin genes; however, the induction of transcripts occurred at later times (15 days). Conclusion: DENV-1 virus inhibited the expression of defensin A and cecropin A genes in a wild Ae. aegypti population from Venezuela.