Multi-functional flow cytometry analysis of CD4+ T cells as an immune biomarker for latent tuberculosis status in patients treated with tumour necrosis factor (TNF) antagonists.

Although monitoring tuberculosis (TB) infection during long-term treatment with tumour necrosis factor (TNF) antagonists is of great importance, no monitoring strategy has yet proved successful. Indeed, even the newly proposed interferon-gamma release assays (IGRAs) are known to produce dynamic changes in IFN-γ plasma levels, making them unreliable indicators of patients' pathological/clinical status. We used intracellular cytokine flow cytometry (ICCFC) to investigate the performance of multi-functional CD4(+) T cells producing IFN-γ, interleukin (IL)-2 and/or TNF in response to Mycobacterium tuberculosis-specific antigens in subjects treated with TNF antagonists. Patients were classified into three groups based on their TB status before commencement of treatment and on IFN-γ level fluctuations evaluated by IGRA during a 36-month follow-up period. The cytokine profile of M. tuberculosis-specific CD4(+) T cells showed that latent tuberculosis infection (LTBI) subjects had a higher frequency of double-positive IFN-γ(+) IL-2(+) CD4(+) T cells and triple-positive IFN-γ(+) IL-2(+) TNF(+) CD4(+) T cells compared to those without LTBI, who showed IFN-γ-level fluctuations over time. In contrast, this latter group of patients showed similar proportions of cells producing IFN-γ alone, IL-2 alone and IL-2 in combination with TNF in response to M. tuberculosis-specific antigens. It therefore appears that patients with and without LTBI infection are characterized by different intracellular cytokine profiles. This is the first study evaluating ICCFC in patients treated with TNF antagonists, and suggests that multi-functional analysis of CD4(+) T cells could be useful for ruling out TB infection in patients classified at screening as LTBI-negative but who show IGRA fluctuations under long-term TNF antagonist treatment.

Interferon-γ release assay for tuberculosis in patients with psoriasis treated with tumour necrosis factor antagonists: in vivo and in vitro analysis.

BACKGROUND: Screening for latent tuberculosis infection (LTBI) is mandatory in patients with psoriasis prior to starting on tumour necrosis factor (TNF) blockers. OBJECTIVES: To investigate the longitudinal changes of interferon (IFN)-γ response to Mycobacterium tuberculosis-specific antigens by serial QuantiFERON-TB Gold In-Tube (QFT-GIT) testing in patients with psoriasis during long-term anti-TNF therapy. The direct in vitro effect of adalimumab on IFN-γ secretion was also evaluated. METHODS: In total, 148 patients with psoriasis designated to start anti-TNF treatment were enrolled. We performed a tuberculin skin test at screening, and QFT-GIT at baseline and serially for 24 months after TNF antagonist onset. RESULTS: At screening, QFT-GIT was positive in 22.3% of the patients, negative in 73.6% and indeterminate in 4%. The IFN-γ response following isoniazid therapy declined and became QFT-GIT negative in 8% of 26 patients with LTBI; in 69% of subjects with LTBI the QFT-GIT remained persistently positive with a significant increase of IFN-γ levels during the follow-up, even if no cases of active tuberculosis were found. Variations of IFN-γ levels were observed also in 7% of 27 patients without LTBI who switched to positive QFT-GIT after 12 or 18 months of biologic therapy, suggesting a new occurrence or reactivation of LTBI. In vitro data showed that in the presence of adalimumab the IFN-γ levels were significantly reduced in a dose-dependent manner (P < 0.05). CONCLUSIONS: Fluctuations of IFN-γ release may occur in patients with psoriasis treated with TNF antagonists. The clinical use of repeated blood tests and the correct interpretation of individual IFN-γ changes could be useful in identifying possible cases of LTBI reactivation or newly acquired tuberculosis infection during long-term anti-TNF treatment.

In vitro effect of anti-human immunodeficiency virus CCR5 antagonist maraviroc on chemotactic activity of monocytes, macrophages and dendritic cells.

Compounds targeting the chemokine receptor CCR5 have recently been approved for treatment of human immunodeficiency virus (HIV) infection. Given the central role of CCR5 in inflammation and recruitment of antigen-presenting cells (APC), it is important to investigate the immunological consequences of pharmacological inhibition of CCR5. We evaluated the in vitro effect of different concentrations of CCR5 antagonist maraviroc (MVC) on cell migration of monocytes, macrophages (MO) and monocyte-derived dendritic cells (MDC) towards peptide formyl-methionyl-leucyl-phenylalanine (fMLP) and chemokines regulated upon activation normal T cell expressed and secreted (RANTES) and CCL4/macrophage inflammatory protein-1 (MIP-1ß) and CCL2/monocyte chemotactic protein-1 (MCP-1). Results of flow cytometric analysis showed that monocytes treated in vitro with MVC exhibited a significant dose-dependent reduction of chemotaxis towards MIP-1ß and MCP-1. fMLP-induced chemotactic activity decreased only at higher concentration (1 µM and 10 µM of MVC). In addition, all concentrations of MVC (0·1, 1 and 10 µM) induced in vitro a significant inhibition of chemotaxis of MO and MDC in response to all tested chemoattractants. No change in phenotype (CD1a and CD14) and CCR1, CCR4, CCR5 and formyl peptide receptor (FPR) expression was seen after in vitro treatment with MVC. These findings suggest that CCR5 antagonist MVC may have the in vitro ability of inhibiting the migration of innate immune cells by mechanism which could be independent from the pure anti-HIV effect. The drug might have a potential role in the down-regulation of HIV-associated chronic inflammation by blocking the recirculation and trafficking of MO and MDC.

Evaluation of QuantiFERON-TB Gold In-Tube in human immunodeficiency virus infection and in patient candidates for anti-tumour necrosis factor-alpha treatment.

SETTING: Cross-sectional study at four out-patient clinics in a single referral centre in Italy. OBJECTIVE: To evaluate the performance of QuantiFERON-TB Gold In-Tube (QFT-GIT) in human immunodeficiency virus (HIV) infected adults and in patients with immune-mediated inflammatory diseases (IMIDs) who are candidates for anti-tumour necrosis factor-alpha (TNF-alpha) treatment. DESIGN: A total of 402 immunocompromised patients were enrolled, including 207 HIV-infected individuals and 195 IMID patients scheduled for anti-TNF-alpha treatment. Tuberculin skin test (TST) and QFT-GIT were performed. For active tuberculosis (TB), test results were compared with microbiological, histopathological and clinical diagnoses. RESULTS: In HIV-infected patients, the level of agreement between the tests was 68% and QFT-GIT sensitivity was 66% (95%CI 47-82). We found a large proportion of indeterminate QFT-GIT results (33.4%), which correlated with CD4 count < 200 cells/microl (P < 0.0001). The degree of agreement with TST was higher in IMID patients (81.6%). Factors associated with discordant positive TST and negative QFT-GIT results were bacille Calmette-Guérin vaccination (P = 0.0001), previous TB (P = 0.0001) and agricultural work (P = 0.0005). CONCLUSION: The performance of QFT-GIT varies between different types of immunocompromised patients. Interferon-gamma release assays should not be used to confirm or rule out a diagnosis of active TB in HIV-infected adults. As there were no cases of active TB in the IMID subgroup, it was difficult to determine which test performs better in this population.

Detection of interleukin-2 in addition to interferon-gamma discriminates active tuberculosis patients, latently infected individuals, and controls.

Effective control of tuberculosis (TB) includes discrimination of subjects with active TB from individuals with latent TB infection (LTBI). As distinct interferon (IFN)-gamma and interleukin (IL)-2 profiles of antigen-specific T-cells have been associated with different clinical stages and antigen loads in several viral and bacterial diseases, we analysed these cytokines in TB using a modified QuantiFERON-TB Gold In Tube test. Detection of IL-2 in addition to IFN-gamma distinguishes not only Mycobacterium tuberculosis-infected subjects from healthy controls, but also individuals with LTBI from active TB patients. This may help to improve diagnostic tests for TB.

Inhibitory activity of Melissa officinalis L. extract on Herpes simplex virus type 2 replication.

Melissa officinalis L. (Lamiaceae) (lemon balm) is used in folk medicine for nervous complaints, lower abdominal disorders and, more recently, for treating Herpes simplex lesions. In this work the antiviral activity of a hydroalcoholic extract of lemon balm leaves against the Herpes simplex virus type 2 (HSV-2) was assessed by the cytopathic effect inhibition assay on Vero cells (ATCC CCL-81), in comparison with acyclovir. The cytotoxicity of the extract on Vero cells was previously tested by evaluating the cellular death and was confirmed by the Trypan blue test. Lemon balm showed to reduce the cytopathic effect of HSV-2 on Vero cells, in the range of non-toxic concentrations of 0.025-1 mg mL(-1) (with reference to the starting crude herbal material). The maximum inhibiting effect (60%) was obtained with 0.5 mg mL(-1). The viral binding assay showed that the extract does not prevent the entry of HSV-2 in the cells, thus suggesting a mechanism of action subsequent to the penetration of the virus in the cell. The extract was also chemically characterised by NMR and HPLC analysis; it showed to contain cinnamic acid-like compounds, mainly rosmarinic acid (4.1% w/w). Our experiments support the use of lemon balm for treating Herpes simplex lesions and encourage clinical trials on this medicinal plant.

HIV protease inhibitor therapy reverses neutrophil apoptosis in AIDS patients by direct calpain inhibition.

The reduction of neutrophils apoptosis is one of the main non-virological effects of protease inhibitor (PI) therapy. We explore here whether this may be due to the cross-inhibition of calpain, an important non-virological target of PI in vitro. We found that the high basal level of neutrophils apoptosis in AIDS patients is strictly related to an increased intracellular calpain activity. Both alterations disappear after PI treatment, with apoptosis and calpain going back to normal levels after 3 months of PI therapy, independently of a proficient antiviral effect. PI drugs exerted a similar antiapoptotic and anticalpain effects on neutrophils in ex vivo experiments: strikingly, the effects were mimicked by commercially available calpain inhibitors. This study shows, for the first time, that apoptosis of neutrophils in AIDS patients is mediated by calpain, and that neutrophil survival in PI treated AIDS patients is a non virological effect due to calpain inhibition.