Scandinavian journal of immunology 2016 9 16() doi 10.1111/sji.12493
Heparin-binding haemagglutinin (HBHA) has been proposed as an immunological biomarker for discriminating active tuberculosis (TB) from latent TB infection (LTBI) and to identify those at higher risk of progressing to active disease. Few data are available in immune compromised patients, which are those with increased risk of TB reactivation.
To evaluate the immune response to HBHA in HIV-infected subjects with LTBI (HIV-LTBI) or active TB (HIV-TB) in comparison with the immune response to additional Mycobacterium tuberculosis (Mtb) or HIV and CMV antigens. The responses are evaluated in relation to TB status and, in the LTBI subjects with the progression to active TB within 2 years.
Forty-one HIV-infected antiretroviral-naïve subjects were prospectively enrolled, 18 were HIV-TB, 23 HIV-LTBI. Whole blood was in vitro stimulated overnight with several antigens and Mitogen. Interferon-γ response in the harvested-plasma was evaluated by ELISA. Despite the CD4-cell count was significantly different between HIV-LTBI and HIV-TB, no differences were observed in response to Mtb- or HIV-specific antigens. Differently, low responses to HBHA were observed in both HIV-LTBI and HIV-TB subjects. Importantly, none of the 6 HIV-LTBI responding to HBHA developed TB while 2/17 of the non-HBHA responders developed active disease.
HIV-TB coinfected subjects, regardless of their TB status, showed low responses to HBHA despite maintaining detectable responses to other antigens; moreover, among the HIV-LTBI, the lack of HBHA-responses indicated an increased risk to develop active TB. These results, although preliminary, suggest that a positive response to HBHA in HIV-LTBI correlates with Mtb containment. This article is protected by copyright. All rights reserved.