Cytometric detection of antigen-specific IFN-γ/IL-2 secreting cells in the diagnosis of tuberculosis
1 Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, 00161 Roma, Italy
2 Translational Research Unit, Department of Experimental Research, Istituto Nazionale Malattie Infettive Lazzaro Spallanzani- IRCCS Rome, 00149 Roma, Italy
BMC Infectious Diseases 2009, 9:99 doi:10.1186/1471-2334-9-99Published: 23 June 2009
The purpose of this study was to further characterize the immune response to Mycobacterium tuberculosis (Mtb) antigens, in order to provide new insight into host-pathogen interactions in tuberculosis (TB), and to offer tools for a more accurate diagnosis of the different stages of TB.
T-cell responses to Bacillus Calmette-Guérin (BCG), purified protein derivative (PPD), early secretory antigenic target-6 (ESAT-6) protein and culture filtrate protein-10 kDa (CFP-10) were measured in terms of interferon (IFN)-γ and interleukin (IL)-2 release, using a novel flow cytometric cell-secreting cytokine detection technique. The study was conducted on peripheral blood mononuclear cells (PBMC) obtained from active TB patients, latently TB infected individuals, and healthy donors. IL-10 and IL-17 were also measured to test their possible role as indicators of disease activity.
We confirmed that the enumeration of IFN-γ releasing cells upon Mtb-specific stimulation is sufficient to identify TB patients and that CD8+ T cells concur to IFN-γ secretion. IL-2 secreting cells were more frequently observed in latent TB infected individuals compared to active TB patients, suggesting that measurement of cells secreting this cytokine could be a marker of disease stage. No discriminating role was associated to IL-10 and IL-17 release in TB patients.
Our data indicate that the flow cytometric cytokine-secreting cell detection technique may be envisaged as an additional tool for TB diagnosis allowing the analysis of the immune response to M. tuberculosis-related antigens in the different stages of TB.