RESUMO
BACKGROUND: Acute inflammatory reactions are a frequently occurring, tissue destructing phenomenon in infectious- as well as autoimmune diseases, providing clinical challenges for early diagnosis. In leprosy, an infectious disease initiated by Mycobacterium leprae (M. leprae), these reactions represent the major cause of permanent neuropathy. However, laboratory tests for early diagnosis of reactional episodes which would significantly contribute to prevention of tissue damage are not yet available. Although classical diagnostics involve a variety of tests, current research utilizes limited approaches for biomarker identification. In this study, we therefore studied leprosy as a model to identify biomarkers specific for inflammatory reactional episodes. METHODS: To identify host biomarker profiles associated with early onset of type 1 leprosy reactions, prospective cohorts including leprosy patients with and without reactions were recruited in Bangladesh, Brazil, Ethiopia and Nepal. The presence of multiple cyto-/chemokines induced by M. leprae antigen stimulation of peripheral blood mononuclear cells as well as the levels of antibodies directed against M. leprae-specific antigens in sera, were measured longitudinally in patients. RESULTS: At all sites, longitudinal analyses showed that IFN-γ-, IP-10-, IL-17- and VEGF-production by M. leprae (antigen)-stimulated PBMC peaked at diagnosis of type 1 reactions, compared to when reactions were absent. In contrast, IL-10 production decreased during type 1 reaction while increasing after treatment. Thus, ratios of these pro-inflammatory cytokines versus IL-10 provide useful tools for early diagnosing type 1 reactions and evaluating treatment. Of further importance for rapid diagnosis, circulating IP-10 in sera were significantly increased during type 1 reactions. On the other hand, humoral immunity, characterized by M. leprae-specific antibody detection, did not identify onset of type 1 reactions, but allowed treatment monitoring instead. CONCLUSIONS: This study identifies immune-profiles as promising host biomarkers for detecting intra-individual changes during acute inflammation in leprosy, also providing an approach for other chronic (infectious) diseases to help early diagnose these episodes and contribute to timely treatment and prevention of tissue damage.
Assuntos
Biomarcadores/análise , Citocinas/imunologia , Hanseníase/imunologia , Mycobacterium leprae/patogenicidade , Bangladesh , Brasil , Citocinas/sangue , Etiópia , Feminino , Interações Hospedeiro-Patógeno , Humanos , Imunidade Humoral/imunologia , Interleucina-10/sangue , Interleucina-17/sangue , Hanseníase/diagnóstico , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/microbiologia , Masculino , Pessoa de Meia-Idade , Mycobacterium leprae/imunologia , Nepal , Estudos ProspectivosRESUMO
Mycobacterium tuberculosis DosR regulon-encoded proteins elicit strong immune T-cell responses in individuals with latent tuberculosis (LTBI). Also, resuscitation (Rpf) proteins can induce such responses. However, variations in the immunogenicity of the DosR and Rpf proteins have been observed in European and African populations, and no data are published from other geographic areas. In Colombian LTBI and patients with recently diagnosed PTB, we therefore studied the immune response to DosR, Rpf, stress, and nominal antigens from Mtb, in 7-day stimulated cultures. Three DosR (Rv1737c, Rv2029c, Rv2628c) and 2 Rpf (Rv0867 and Rv2389c) antigens were recognized most prominently on the basis of the net IFNγ production (DosR) or the percentage of responding individuals (Rpf). Results show that the selected DosR antigens induced a higher proportion of CD4-T cells producing IFNγ from LTBI, compared to pulmonary TB patients (PTB), while there were no differences in the proportion of CD8-T cells. An increased frequency of CD4, but not CD8 T-cells with a CD45RO(+)CD27(+) phenotype was observed in LTBI in response to Rv2029c, Rv0867c, and Rv2389c, compared to PTB. The levels of cytokines and chemokines in the supernatants of stimulated cells, showed that the DosR and Rpf antigens induced higher levels of IFNγ in cultures from LTBI compared to PTB, although the induced pattern of cytokines and chemokines was also antigen dependent. In summary, our results are consistent with the significant immunogenicity of Mtb DosR and Rpf antigens in LTBI individuals, and confirm and extend previously reported data from other TB affected human populations.
Assuntos
Proteínas de Bactérias/imunologia , Citocinas/imunologia , Tuberculose Latente/imunologia , Proteínas Quinases/imunologia , Subpopulações de Linfócitos T/imunologia , Tuberculose Pulmonar/imunologia , Adolescente , Adulto , Idoso , Antígenos de Bactérias/imunologia , Relação CD4-CD8 , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Quimiocinas/biossíntese , Colômbia , Citocinas/biossíntese , Proteínas de Ligação a DNA , Feminino , Humanos , Memória Imunológica , Imunofenotipagem , Interferon gama/biossíntese , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/imunologia , Adulto JovemRESUMO
IFN-gamma responses to Mycobacterium tuberculosis antigens ESAT-6 and CFP-10 have been proposed as specific markers of M. tuberculosis infection. Monokine induced by gamma interferon (MIG/CXCL9) has been shown to be expressed by IFN-gamma stimulated mononuclear cells and to attract activated T-cells through the chemokine receptor CXCR3. Since MIG is induced early in the response to IFN-gamma, measuring MIG may provide an interesting marker to assess downstream IFN-gamma induced responses, in contrast to assays that mainly focus on quantifying production of IFN-gamma per se. We, therefore, investigated MIG and IFN-gamma responses to a fusion protein of ESAT-6 and CFP-10, and compared responses to the conserved mycobacterial antigen 85B (Ag85B) and purified protein derivative (PPD) of M. tuberculosis, in 29 BCG vaccine controls and 24 TB patients. IFN-gamma secreting cells were determined by ELISPOT, and MIG production was measured by ELISA and flow cytometry. Production of MIG in response to ESAT-6/CFP-10, Ag85B and PPD correlated overall with increased numbers of IFN-gamma secreting cells (r=0.55, P<0.0001). A significant increase was noted among patients compared to controls in the secretion of IFN-gamma and MIG following stimulation with ESAT-6/CFP-10 or PPD (P<0.05). Moreover, MIG intracellular expression was higher in TB patients compared to BCG vaccines (P<0.05) in response to ESAT-6/CFP-10 or PPD. We conclude that MIG production correlates significantly with enhanced T-cell IFN-gamma production induced by M. tuberculosis-specific antigens ESAT-6/CFP-10. These results point to MIG as a potential novel biomarker that may be helpful in assessing downstream responses induced by IFN-gamma in TB.