A clinical utility evaluation of dual HIV/Syphilis point-of-care tests in non-clinical settings for screening for HIV and syphilis in men who have sex with men.

BACKGROUND: Dual point-of-care tests (POCTs) for the simultaneous detection of antibodies to HIV and syphilis have been developed. Since community-based organisations (CBO) are effective providers of HIV and syphilis testing among men who have sex with men (MSM), evaluation of the utility of these dual tests at CBO testing services is a high priority. The aim of this study is to determine the feasibility of performing dual HIV-syphilis POCT testing among both users and providers at these non-clinical sites. METHODS: This evaluation assessed the utility of two lateral flow immunochromatographic antibody technologies for dual screening for HIV/syphilis among MSM seeking testing in four CBO testing services in Spain, Slovenia, Latvia, and Ukraine. The study's conceptual framework divides the concept of feasibility into two inter-related domains, acceptability, and usability and further breaks it down into six subdomains: learnability, willingness, suitability, satisfaction, efficacy, and effectiveness. The feasibility analysis was performed by calculating the median score in 3 stages (for individual questions, subdomains, and domains), using a summated scores method. RESULTS: The final sample included 844 participants, 60 of which were found to be HIV test positive (7.1%) and 61 (7.2%) positive on testing for syphilis. There was a small difference (1.1%) when comparing the results of the two dual POCTs under evaluation to the tests routinely used at each site. The inter-rater agreement showed a high concordance between two independent readings. The analysis of the feasibility for the users of the services indicated good satisfaction, suitability, and willingness. In addition, among 18 providers the total mean score showed good acceptability and usability, good willingness, easy learnability, high suitability, and good efficacy, but lower satisfaction and effectiveness. The operational characteristics of both dual study POCTs were well evaluated by providers. CONCLUSIONS: The introduction of dual HIV and syphilis  POCTs in CBO testing services for screening of MSM is feasible, with a high acceptability and usability both for users and providers. Implementation of dual POCTs for HIV and syphilis in CBO testing services is an opportunity for scaling up integrated HIV/syphilis testing for MSM.

Validation study of an automated chemiluminiscence assay to detect HIV antibodies in oral fluid specimens.

Oral fluid specimens (OF) have been widely used to know the HIV prevalence in several key populations. Here, we aim to validate in OF specimens an existing HIV chemiluminiscence assay for serum specimens. Paired OF and serum specimens were collected from 83 known HIV-positives and 83 known HIV-negatives in order to validate the performance characteristics of the automated chemiluminiscence Liaison XL Murex HIV Ag/Ab assay (Diasorin Inc, Iberia) for HIV antibody detection in OF specimens. Among the previously known HIV-seropositive group, HIV antibodies were detected in 69 out of 83 OF specimens. All serum and OF specimens collected from 83 HIV seronegative individuals were negative. The sensitivity and specificity of this assay were 83.13% and 100% respectively in OF. The PPV and NPV values were 100% and 85.57% respectively. The correlation obtained between both specimens was (K: 0.83, [95% CI: 0.748-0.915]) according to the kappa index. The ROC curve analysing the optimal cut-off of the Liaison XL Murex HIV Ag/Ab to detect positive OF specimens revealed that a cut-off of 0.497 showed sensitivity and specificity values of 98.8% and 97.59% respectively. Taking into account this cut-off, the overall sensitivity and NPV of the Liaison XL Murex HIV Ag/Ab assay could rise from 83.1 to 98.8% and from 85.5 to 97.7%, respectively. Our results suggest that the Liaison XL HIV Ag/Ab assay is suitable for the detection of HIV antibodies in OF specimens.

GM-CSF produced by nonhematopoietic cells is required for early epithelial cell proliferation and repair of injured colonic mucosa.

GM-CSF is a growth factor that promotes the survival and activation of macrophages and granulocytes, as well as dendritic cell differentiation and survival in vitro. The mechanism by which exogenous GM-CSF ameliorates the severity of Crohn's disease in humans and colitis in murine models has mainly been considered to reflect its activity on myeloid cells. We used GM-CSF-deficient (GM-CSF(-/-)) mice to probe the functional role of endogenous host-produced GM-CSF in a colitis model induced after injury to the colon epithelium. Dextran sodium sulfate (DSS), at doses that resulted in little epithelial damage and mucosal ulceration in wild type mice, caused marked colon ulceration and delayed ulcer healing in GM-CSF(-/-) mice. Colon crypt epithelial cell proliferation in vivo was significantly decreased in GM-CSF(-/-) mice at early times after DSS injury. This was paralleled by decreased expression of crypt epithelial cell genes involved in cell cycle, proliferation, and wound healing. Decreased crypt cell proliferation and delayed ulcer healing in GM-CSF(-/-) mice were rescued by exogenous GM-CSF, indicating the lack of a developmental abnormality in the epithelial cell proliferative response in those mice. Nonhematopoietic cells, and not myeloid cells, produced the GM-CSF important for colon epithelial proliferation after DSS-induced injury, as revealed by bone marrow chimera and dendritic cell-depletion experiments, with colon epithelial cells being the cellular source of GM-CSF. Endogenous epithelial cell-produced GM-CSF has a novel nonredundant role in facilitating epithelial cell proliferation and ulcer healing in response to injury of the colon crypt epithelium.

Increased production of the ether-lipid platelet-activating factor in intestinal epithelial cells infected by Salmonella enteritidis.

When exposed to enteric pathogens intestinal epithelial cells produce several cytokines and other proinflammatory mediators. To date there is no evidence that the ether-lipid platelet-activating factor (PAF) is one of these mediators. Our results revealed a significant increase in PAF production by human colonic tissue 4 h after infection by enterohemorrhagic Escherichia coli (EHEC) or Salmonella enteritidis. PAF is produced in the gut by cells of the immune system in response to bacterial infection. To determine whether the epithelial cells of colonic mucosa might also modulate PAF levels, we carried out PAF quantification and analysis of the enzymes involved in PAF synthesis in 5-day-old (undifferentiated) or 28-day-old (differentiated) Caco-2 cell cultures. Infection of undifferentiated Caco-2 cells with either bacterium had no effect on PAF levels, whereas in differentiated cells, infection by S. enteritidis increased PAF levels. Following infection by S. enteritidis, there were no changes in the activity of dithiothreitol-insensitive choline phosphotransferase. However, the enzymes of the remodeling pathway cytosolic phospholipase A(2), which catalyzes the formation of the PAF precursor lysoPAF, and lysoPAF acetyltransferase, are activated in the infected epithelial cells. This response is Ca(2+)-dependent.

GM-CSF: a role in immune and inflammatory reactions in the intestine.

Granulocyte macrophage colony-stimulating factor (GM-CSF) is a cytokine that promotes myeloid cell development and maturation, and dendritic cell differentiation and survival in vitro. Growing evidence supports the notion that GM-CSF has a major role in some inflammatory and autoimmune reactions and in the host's response to pulmonary infection, but few studies have addressed its functions and importance in the GI tract. Recent studies demonstrated that administration of GM-CSF can result in clinical improvement in patients with Crohn's disease. Mice deficient in GM-CSF (GM-CSF(-/-) ) developed more severe intestinal and systemic infection after an enteric infection, and more severe colitis in response to enteric exposure to dextran sodium sulfate. Both the severity of infection and colitis were largely prevented by GM-CSF administration. Such studies indicate that GM-CSF has an important role in the regulation of intestinal immune and inflammatory responses.

GM-CSF-facilitated dendritic cell recruitment and survival govern the intestinal mucosal response to a mouse enteric bacterial pathogen.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes dendritic cell (DC) differentiation and survival in vitro. However, its role in host defense at the intestinal mucosa is unknown. We report that infection with the mouse enteric pathogen, Citrobacter rodentium, increased colonic GM-CSF production and CD11c(+) DC recruitment. After infection, GM-CSF(-/-) mice had fewer mucosal CD11c(+) DCs, greater bacterial burden, increased mucosal inflammation and systemic spread of infection, decreased antibody responses, and delayed pathogen clearance. This defective mucosal response was rescued by GM-CSF administration to GM-CSF(-/-) mice and mimicked by CD11c(+) DC depletion in wild-type animals. Diminished mucosal DC numbers in infected GM-CSF(-/-) mice reflected decreased DC recruitment and survival, with the recruitment defect being related to a failure to upregulate epithelial cell production of the DC chemoattractant, CCL22. Thus, GM-CSF produced in the intestinal mucosa acts to enhance host protection against an enteric bacterial pathogen through regulating recruitment and survival of DCs.