T-SPOT.TB responses during treatment of pulmonary tuberculosis

<p>Abstract</p> <p>Background</p> <p>Immune responses to <it>Mycobacterium tuberculosis </it>antigens could serve as surrogate markers of treatment response.</p> <p>Methods</p> <p>Using the T-SPOT.<it>TB </it>assay and frozen peripheral blood mononuclear cells, we enumerated ESAT-6- and CFP-10-specific IFN-γ-producing T cells over time in pulmonary TB patients receiving directly observed treatment. T cell responses (measured as "spot forming cells" or "SFCs") were assessed prior to treatment and at 16 and 24 weeks of treatment.</p> <p>Results</p> <p>58 patients were evaluated, of whom 57 were HIV seronegative. Mean (SD) ESAT-6, CFP-10, and summed RD1 specific SFCs declined from 42.7 (72.7), 41.2 (66.4), and 83.8 (105.7) at baseline to 23.3 (39.4, p = 0.01), 23.2 (29.4, p = 0.18), and 46.5 (59.5, p = 0.02) at completion of 24 weeks of treatment, respectively. Only 10% of individuals with a baseline reactive test reverted to negative at treatment week 24. For the group that was culture positive at completion of 8 weeks of treatment compared to the culture negative group, the incidence rate ratio (IRR) of ESAT-6, CFP-10, and summed RD1 specific SFC counts were, respectively, 2.23 (p = 0.048), 1.51 (p = 0.20), and 1.83 (p = 0.047). Patients with cavitary disease had mean ESAT-6 specific SFC counts that were higher than those without cavitary disease (IRR 2.08, p = 0.034).</p> <p>Conclusion</p> <p>IFN-γ-producing RD1-specific T cells, as measured in the T-SPOT.<it>TB </it>assay, may be directly related to bacterial load in patients undergoing treatment for pulmonary TB. However, high inter-subject variability in quantitative results coupled with failure of reversion to negative of qualitative results in most subjects at treatment completion may limit the utility of this assay as a surrogate marker for treatment efficacy.</p

T-cell-based diagnosis of tuberculosis infection in children in Lithuania: a country of high incidence despite a high coverage with bacille Calmette-Guerin vaccination

<p>Abstract</p> <p>Background</p> <p>Lithuania is a country with a high incidence of tuberculosis (TB), despite a high coverage with bacille Calmette-Guerin (BCG) vaccination. Until now the only method used to detect latent TB infection was the tuberculin skin test (TST). However, TST may have a cross reactivity to the BCG vaccine and to environmental mycobacteria. The aim of this study was to conduct assessments of the diagnostic accuracy of the T-cell based test (T SPOT TB) for TB in children who had previously been BCG vaccinated and compare these with the results of the TST.</p> <p>Methods</p> <p>Between January 2005 and February 2007, children with bacteriologically confirmed TB, children having contacts with a case of infectious pulmonary TB and children without any known risk for TB were tested with both the TST and T SPOT TB.</p> <p>Results</p> <p>The TST and T SPOT TB tests were positive for all patients in the „culture-confirmed TB“ group. Whereas, in the „high risk for TB“ group, the TST was positive for 60%, but the T SPOT TB test, only for 17.8%. Meanwhile the results for the „low risk for TB“ group were 65.4% and 9.6%, respectively. A correlation between the TST and T SPOT TB was obtained in the "culture-confirmed TB" group where the TST ≥15 mm (r = 0.35, p < 0.001).</p> <p>Conclusion</p> <p>The T-cell based method is more objective than the TST for identifying latent TB infection in children who had been previously BCG vaccinated. This method could be useful in countries like Lithuania where there is a high incidence of TB despite a high coverage with BCG vaccination. It may also help to avoid unnecessary chemoprophylaxis when TST reactions are false-positive.</p

Effect of Recombinant Cytokines on the Expression of Natural Killer Cell Receptors from Patients with TB or/and HIV Infection

BACKGROUND: NK cells express several specialized receptors through which they recognize and discriminate virally-infected/tumor cells efficiently from healthy cells and kill them. This ability to lyse is regulated by an array of inhibitory or activating receptors. The present study investigated the frequency of various NK receptors expressed by NK cell subsets from HIV-infected TB patients. The effect of IL-15+IL-12 stimulation on the expression of NK receptors was also studied. METHODOLOGY/PRINCIPAL FINDINGS: The study included 15 individuals each from normal healthy subjects, pulmonary tuberculosis patients, HIV-infected individuals and patients with HIV and tuberculosis co-infection. The expression of NK cell receptors was analyzed on two NK cell subsets within the peripheral blood: CD16+CD3- and CD56+CD3- using flow cytometry. The expression of inhibitory receptors (CD158a, CD158b, KIRp70, CD85j and NKG2A) on NK subsets was increased in HIV, when compared to NHS. But the response in HIV-TB was not uniform. Stimulation with IL-15+IL-12 dropped (p<0.05) the expression of CD85j and NKG2A in HIV. The basal expression of natural cytotoxicity receptors (NKp30 and NKp46) on NK cell subsets was lowered (p<0.05) in HIV and HIV-TB as compared to NHS. However, the expression of NKp44 and NKG2D was elevated in HIV. Enhanced NKp46 and NKG2D expression was observed in HIV with IL-15+IL-12 stimulation. The coreceptor NKp80 was found to be expressed in higher numbers on NK subsets from HIV compared to NHS, which elevated with IL-15+IL-12 stimulation. The expression of NK receptors and response to stimulation was primarily on CD56+CD3- subset. CONCLUSIONS/SIGNIFICANCE: IL-15+IL-12 has an immunomodulatory effect on NK cell subsets from HIV-infected individuals viz down-regulation of iNKRs, elevation of activatory receptors NKp46 and NKG2D, and induction of coreceptor NKp80. IL-15+IL-12 is not likely to be of value when co-infected with TB probably due to the influence of tuberculosis

Ergoline Derivatives as a Probe for Featuring the 5-HT 1A Receptor Pharmacophore

A 5-HT1A pharmacophore has been obtained employing a set of rigid templates encompassing the 5-HT structure. The use of rigid templates allowed us to overcome the discrepancy found when flexible structures where the energy of the active conformers are sometimes higher than the global minimum energy are used. On the basis of the results herein reported the three-dimensional requirements necessary for the binding interaction have been defined within this set of molecules. In this study forbidden zones of the receptor have been characterised. The pharmacophore model derived places some agonist/antagonist pharmacophore models appeared in the literature in question

Inhibition of protein-protein interactions: the discovery of druglike beta-catenin inhibitors by combining virtual and biophysical screening.

The interaction between beta-catenin and Tcf family members is crucial for the Wnt signal transduction pathway, which is commonly mutated in cancer. This interaction extends over a very large surface area (4800 A(2)), and inhibiting such interactions using low molecular weight inhibitors is a challenge. However, protein surfaces frequently contain "hot spots," small patches that are the main mediators of binding affinity. By making tight interactions with a hot spot, a small molecule can compete with a protein. The Tcf3/Tcf4-binding surface on beta-catenin contains a well-defined hot spot around residues K435 and R469. A 17,700 compounds subset of the Pharmacia corporate collection was docked to this hot spot with the QXP program; 22 of the best scoring compounds were put into a biophysical (NMR and ITC) screening funnel, where specific binding to beta-catenin, competition with Tcf4 and finally binding constants were determined. This process led to the discovery of three druglike, low molecular weight Tcf4-competitive compounds with the tightest binder having a K(D) of 450 nM. Our approach can be used in several situations (e.g., when selecting compounds from external collections, when no biochemical functional assay is available, or when no HTS is envisioned), and it may be generally applicable to the identification of inhibitors of protein-protein interactions

Contact investigation based on serial interferon-gamma release assays (IGRA) in children from the hematology-oncology ward after exposure to a patient with pulmonary tuberculosis.

BACKGROUND: Interferon-gamma release assays (IGRAs) have high specificity and sensitivity for the diagnosis of tuberculosis (TB) infection. However, their role as a screening tool in children with immunodeficiency disorders is still unclear. In the present study, we performed a contact investigation using serial IGRAs on children with immunodeficiency conditions exposed to a contagious TB patient. METHODS: Children who were exposed to a contagious TB case underwent serial QuantiFERON(®) TB Gold In-Tube (QFT-GIT) and T-SPOT(®).TB (T-SPOT) testing. RESULTS: Eighteen children were tested. At the first testing, only two children (11 %) were positive to T-SPOT. Indeterminate results were more frequent with QFT-GIT (35 %) than with T-SPOT (12 %). In the multivariable analysis, a statistically significant association of lymphocyte count <500 cells/mm(3) (p < 0.00005) and low age (p = 0.03) with indeterminate results for the QFT-GIT test but not for T-SPOT (p = 0.10 and p = 0.88, respectively) was found. At the end of October 2012, 15 of the 18 children were alive and none developed active TB disease. CONCLUSION: T-SPOT provided more determinate results and was less influenced by low age and lymphocytopenia than QFT-GIT in this population of immunodeficient children. These findings suggest that T-SPOT is a more accurate test for the identification of TB infection in young children with lymphocytopenia and should be preferred to QFT-GIT under such specific conditions. PMID: 23575516 [PubMed - indexed for MEDLINE