RESUMO
Regulatory T cells (Tregs), a subset of CD4+ T cells related with immune regulation, have been associated with active and latent tuberculosis infection (LTBI). Treg frequencies were evaluated by multicolor flow cytometry (FC) in peripheral blood mononuclear cells (PBMCs) stimulated with mycobacterial antigens ESAT-6, CFP-10, and TB7.7 to assess their capacity to distinguish subjects with different reactivity to the QuantiFERON-TB® Gold In-Tube (QFT-IT) test and the tuberculin skin test (TST). Increased frequencies of CD4+CD25highCD39+ cells were found for the [TST+, QTF+] compared with the [TST+, QTF-] group. Also, higher frequencies were observed for the [TST+, QTF+] compared with the [TST+, QTF-] and [TST-, QTF-] groups in CD4+CD25highFoxp3+ and CD4+CD25highCD39+Foxp3+ populations. Receiver operating characteristics (ROC curve) analysis confirmed these discriminating results. QFT-IT and TST quantitative values correlated with several Treg population frequencies.
Assuntos
Antígenos de Bactérias/imunologia , Testes de Liberação de Interferon-gama , Tuberculose Latente/imunologia , Mycobacterium tuberculosis/imunologia , Linfócitos T Reguladores/imunologia , Teste Tuberculínico , Tuberculose Pulmonar/transmissão , Adulto , Antígenos CD/metabolismo , Apirase/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Estudos de Coortes , Feminino , Fatores de Transcrição Forkhead/metabolismo , Humanos , Técnicas In Vitro , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Subunidade alfa de Receptor de Interleucina-7/metabolismo , Leucócitos Mononucleares , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/metabolismo , Adulto JovemRESUMO
We have hypothesized that individuals infected with Mycobacteriumtuberculosis that exhibit different patterns of immune reactivity in serial interferon (IFN)-γ release assays (IGRA's) correspond to different status within the immune spectrum of latent tuberculosis (TB). Accordingly, we analyzed the possible association between the consistent results (negative or positive) in an IGRA test and relevant immune parameters, mainly the levels of Th1 and Th17 lymphocytes and T regulatory (Treg) cells in the peripheral blood of TB case contacts. We found that individuals with a persistently positive IGRA showed increased levels of Th1 and Th17 lymphocytes upon in vitro stimulation with MTB antigens. In addition, a significant increase in the proportion of CD4+CTLA-4+ and CD4+Foxp3+ cells was detected in assays with blood samples from these individuals. Our data support that different immune phenotypes can be identified into the spectrum of latent TB, by combining different parameters of immune reactivity against MTB.
