RESUMO
Mycobacterium tuberculosis (MTB)-specific cytokine responses in the peripheral blood and at the site of infection may differ significantly within the same individual, but the under-lying T-cell subset changes are largely unknown. Here, we measured effector and memory T-cell markers on CD4⺠T cells (CD45RO, cysteine chemokine receptor (CCR)7, and CD27) in peripheral blood and at the site of active tuberculosis (TB). Additionally, T cells were stimulated overnight with purified protein derivative (PPD) and early secretory antigenic target (ESAT)-6 to determine which T-cell subset produces MTB-specific interferon (IFN)-γ. A striking decrease in CCR7 and CD27 expression on T cells was noted at the site of active TB. Likewise, IFN-γ expressing, ESAT-6 specific CD4âºCD45ROâºCD27â» T cells were dramatically increased at the site of infection but were not detectable in peripheral blood. An antigen-specific expansion of differentiated T cells at the site of active TB infection was poorly reflected in peripheral blood. Insight in these changes in MTB-specific effector T cells in different compartments of the body could lead to new approaches for immune-based diagnosis and interventions.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Mycobacterium tuberculosis/imunologia , Receptores CCR7/imunologia , Subpopulações de Linfócitos T/imunologia , Tuberculose/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Linfócitos T CD4-Positivos/patologia , Feminino , Citometria de Fluxo , Humanos , Interferon gama/sangue , Interferon gama/imunologia , Antígenos Comuns de Leucócito/sangue , Antígenos Comuns de Leucócito/imunologia , Leucócitos Mononucleares/imunologia , Masculino , Pessoa de Meia-Idade , Receptores CCR7/sangue , Estatísticas não Paramétricas , Subpopulações de Linfócitos T/patologia , Tuberculina/farmacologia , Tuberculose/sangue , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/sangue , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
The antimicrobial peptide cathelicidin LL-37 possesses antituberculous activity, its association with other mycobacterial diseases, such as leprosy, is unknown. We studied serum cathelicidin and 25OH-vitamin D3 levels in 29 leprosy patients and 19 healthy individuals from Yemen. Cathelicidin levels were significantly lower in both treated (n=15) and untreated leprosy patients (n=14) when compared to controls (P<0.001). Within leprosy patients, levels were lower in those who very recently developed disease (untreated group) when compared to already treated patients (P<0.05). 25OH-vitamin D3 levels were not different between groups. The results suggest a potential association of cathelicidin LL-37 with Mycobacterium leprae infection.