Synovial Biomarkers to Detect Chronic Periprosthetic Joint Infection: A Pilot Study to Compare Calprotectin Rapid Test, Calprotectin ELISA Immunoassay and Leukocyte Esterase Test.

BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication after joint replacement surgery, and making diagnosis is often far from obvious. Calprotectin was recently proposed as a promising synovial biomarker to detect PJI. To our knowledge, no comparative study exists between enzyme-linked immunosorbent assay (ELISA) and rapid calprotectin test (CalFAST). Our purpose was to compare these methods with leukocyte esterase (LE) test from synovial fluid of painful knee arthroplasty subjected to infectious workup. METHODS: Ninety-three patients were included in this prospective observational study. They underwent synovial fluid aspiration that was analyzed for cell count, microbiological culture, LE test, calprotectin rapid test, and calprotectin immunoassay dosage. The 2018 Consensus Statements criteria for PJI were used to diagnose PJI. Sensitivity, specificity, positive and negative likelihood ratio, and receiver operating characteristic were calculated for detection methods and compared. RESULTS: We categorized 39 patients as infected and 50 patients as not infected. The sensitivity comparing the ELISA test and CalFAST test was similar, 92.3% and 97.4%, respectively. LE rapid test showed 46% of sensitivity and 94% of specificity. The highest specificity was found with ELISA test (100%). Comparing the receiver operating characteristic curves by z-test, there were statistically significant differences between LE strip test and the other two methods. Otherwise, no statistically significant differences were present between ELISA and CalFAST test. CONCLUSION: Synovial calprotectin detection has high accuracy in knee PJI diagnosis, both ELISA and rapid test. LE strip test remains a good test to confirm the diagnosis of PJI in case of positivity. In clinical practice, the calprotectin rapid test can be considered an excellent point-of-care test.

Seroprevalence of SARS-CoV-2-Specific Antibodies in Cancer Patients Undergoing Active Systemic Treatment: A Single-Center Experience from the Marche Region, Italy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in cancer patients may vary widely dependent on the geographic area and this has significant implications for oncological care. The aim of this observational, prospective study was to assess the seroprevalence of SARS-CoV-2 IgM/IgG antibodies in solid cancer patients referred to the academic institution of the Marche Region, Italy, between 1 July and 26 October 2020 and to determine the accuracy of the rapid serological test. After performing 3767 GCCOV-402a rapid serological tests on a total of 949 patients, seroconversion was initially observed in 13 patients (1.4%). Ten (77% of the total positive) were IgG-positive, 1 (8%) were IgM-positive and 2 (15%) IgM-positive/IgG-positive. However, only 7 out of 13 were confirmed as positive at the reference serological test (true positives), thus seroprevalence after cross-checking was 0.7%. No false negatives were reported. The kappa value of the consistency analysis was 0.71. Due to rapid serological test high false positive rate, its role in assessing seroconversion rate is limited, and the standard serological tests should remain the gold standard. However, as rapid test negative predictive value is high, GCCOV-402a may instead be useful to monitor patient immunity over time, thus helping to assist ongoing vaccination programs.

Synovial Fluid Calprotectin for the Preoperative Diagnosis of Chronic Periprosthetic Joint Infection.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) represents a challenge in clinical practice and the analysis of synovial fluid is a useful diagnostic tool. Calprotectin is an inflammatory biomarker widely used in the evaluation of chronic inflammatory diseases; however, little is known about its role in PJI. The purpose of this study is to determine the reliability of synovial calprotectin in the diagnosis of PJI. METHODS: Seventy-six patients with painful knee arthroplasty were included in this prospective observational study. Synovial fluid was analyzed for cell count, percentage of polymorphonuclear neutrophils, microbiological culture, leukocyte esterase strip test, alpha-defensin rapid test, and calprotectin immunoassay dosage. The 2018 Consensus Statements criteria for PJI were used as standard reference to define the presence of infection. Sensitivity, specificity, positive and negative likelihood ratio, and receiver-operation characteristic curve were calculated for calprotectin immunoassay test. RESULTS: By 2018 Consensus Statements criteria for PJI, 28 patients were considered infected, 44 patients were considered not infected, and 4 patients were classified as inconclusive. The calprotectin synovial fluid test resulted in 2 false-positive results and no false-negative results. The calprotectin synovial fluid test demonstrated a sensitivity of 100% (95% confidence interval [CI] 99.96-100) and specificity of 95% (95% CI 89.4-100) for the diagnosis of PJI. The positive likelihood ratio was 22 (95% CI 5.680-85.209) and the negative likelihood ratio was 0 (95% CI 0-0.292). The area under the receiver-operation characteristic curve was 0.996 (95% CI 94.3-100). CONCLUSION: The present study suggests that synovial calprotectin immunoassay test has a high sensitivity and specificity in the diagnosis of knee PJI. Moreover, it is easily applied, quick and valuable in clinical practice.

GABRA2 and alcohol use disorders: no evidence of an association in an Italian case-control study.

BACKGROUND: Alcoholism is a major health and social issue, a highly frequent disease and a cause of premature death. It is also the most expensive addictive disorder being related to high morbidity and mortality, violence, accidents, and social and legal problems. It is a quantitative disorder, where the combined incidence of environmental and multiple genetic factors varies from 1 subject to another. Recent association studies have identified several genes as candidates for alcoholism, including GABAA receptor genes, due to their role in mediating several behavioral effects of alcohol, such as motor incoordination, anxiolysis, sedation, and withdrawal. The proposed association between the 3' half of the gene encoding the alpha-2 subunit of GABA receptor (3'-GABRA2) and alcohol use disorders (AUDs) has received several independent confirmations. METHODS: In this study, 10 single nucleotide polymorphisms (SNPs) of the 3'-GABRA2 gene, previously reported to be implicated in alcohol dependence, were used to evaluate the linkage between selected SNPs and AUDs in an Italian sample and to compare findings with those of previous studies. RESULTS: No evidence of an association was found at the allele, genotype, haplotype, or diplotype levels between the 3'-GABRA2 polymorphisms investigated and alcoholism in 149 Italian alcoholics (98 alcohol dependents and 51 alcohol abusers) and 278 controls. CONCLUSIONS: Despite previous reports, we did not find an association between AUDs and 3'-GABRA2 polymorphisms. This is probably due to the minimal comorbidity of our Italian sample suggesting that this gene is implicated in polysubstance dependence rather than in alcoholism alone.

Pulse-mediated chemotherapy enhances local control and survival in a spontaneous canine model of primary mucosal melanoma.

Mucosal melanomas account for 1% of all malignant melanomas in humans. Treatment options include surgery, chemotherapy, immunotherapy and radiation therapy; however, local recurrence and distant dissemination are still frequent. We treated locally aggressive spontaneous canine oral melanomas that, because of their advanced stage, were not treatable with conventional strategies. A cohort of 10 dogs with oral melanoma was enrolled over a 4-year period. The dogs received two sessions of local bleomycin, followed by the application of trains of biphasic pulses. The treatment was well tolerated and resulted in an overall response rate of 80% with 50% long-term control. Of interest, only one of the dogs died of metastatic disease, and four of the long-term survivors showed a vitiligo-like discoloration at the site of treatment, potentially suggesting a recruitment of the immune system by the therapy. Further studies are needed to characterize this approach and to determine its suitability for head and neck mucosal melanoma.

Effects of indinavir in a preliminary phase I study on dogs with stage III slenic hemangiosarcoma.

HIV protease inhibitors are antiretroviral drugs able to prevent production of infectious particles. It has been shown that these protease inhibitors are able to inhibit cancer-promoted angiogenesis in patients affected by Kaposi's sarcoma. A preliminary phase I study on dogs with stage III splenic hemangiosarcoma was designed in order to evaluate the efficacy and toxicity of the protease inhibitor Indinavir to delay the progression of this advanced neoplasm. The results suggest that Indinavir is potentially beneficial in dogs affected by microscopic residual disease.

Apelin expression in normal human tissues.

Apelin is an endogenous ligand of the human orphan receptor APJ (orphan G protein-coupled receptor). This peptide is produced through processing from the C-terminal portion in the pre-proprotein consisting of 77 amino acid residues and exists in multiple molecular forms. Although the main physiological functions of apelin have not been clarified yet, it has been demonstrated that apelin partially suppresses cytokine production from mouse spleen and, specifically, induces the promotion of extracellular acidification and inhibition of cAMP production in Chinese hamster ovary cells. Moreover, it is involved in the regulation of blood pressure and blood flow. In this study we have analyzed, by immunohistochemistry, apelin distribution in several human tissues, demonstrating that apelin has a widespread pattern of expression. These results seem to confirm that apelin functions widely in various tissues interacting with its specific receptor APJ.

Immunohistochemical study of apelin, the natural ligand of receptor APJ, in a case of AIDS-related cachexia.

Apelin, a peptide first isolated from bovine stomach extracts, was discovered as an endogenous ligand for the APJ receptor. APJ has been shown to be a co-receptor for human and simian immunodeficiency virus (HIV and SIV). Apelin specifically inhibited the entry of primary T-tropic and dualtropic HIV-1 isolated from different clones expressing antiviral CD4 and APJ. On the basis of these results, we decided to compare the apelin expression level between normal and AIDS-infected tissues by immunohistochemistry. We found that apelin expression was less intense in AIDS-infected tissues compared to normal tissues, in particular in the pancreas, kidney, adrenal glands and lymphoid organs. These results suggest an involvement of this peptide in immunodeficiency and in the immune response to AIDS.