Hepcidin exerts a negative immunological effect in pulmonary tuberculosis without HIV co-infection, prolonging the time to culture-negative

Objectives: A major regulatory peptide in iron metabolism, hepcidin, has been shown to predict mortality in HIV-infected tuberculosis patients. The aim of this study was to evaluate whether plasma hepcidin levels on admission can be used to predict the treatment outcome of patients with smear-positive pulmonary tuberculosis (PTB) without HIV co-infection. Methods: In this prospective observational study, a total of 35 PTB patients with Mycobacterium tuberculosis-positive sputum smears were enrolled. The relationship between plasma hepcidin levels on admission and the time period to sputum culture-negative was explored. Results: Plasma hepcidin levels of PTB patients were significantly higher than those of healthy subjects (p < 0.001). A positive correlation between hepcidin level on admission and the period until culture-negative was also observed (r = 0.46, p = 0.006). Furthermore, the hepcidin level showed a negative correlation with spot numbers in the positive control wells of the T-SPOT. TB assay; thus the effect of the peptide on interferon-gamma production in T cells was explored. Hepcidin reduced interferon-gamma gene transcription and interferon-gamma production in a dose-dependent manner in Jurkat cells stimulated with phytohaemagglutinin, an antigen non-specific stimulation. Conclusions: These findings indicate that hepcidin alters immunological reactions against M. tuberculosis infection and has an influence on the outcomes of PTB patients without HIV co-infection. (C) 2019 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.