Relationship Between HIV Coinfection, Interleukin 10 Production, and Mycobacterium tuberculosis in Human Lymph Node Granulomas

The Journal of Infectious Diseases MAJOR ARTICLE Relationship Between HIV Coinfection, Interleukin 10 Production, and Mycobacterium tuberculosis in Human Lymph Node Granulomas Collin R. Diedrich,1 Jennifer O’Hern,1 Maximiliano G. Gutierrez,4 Nafiesa Allie,2 Patricia Papier,2 Graeme Meintjes,1,3 Anna K. Coussens,1 Helen Wainwright,2,3 and Robert J. Wilkinson1,3,4,5 1 Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, 2Division of Anatomical Pathology, and 3Department of Medicine, University of Cape Town, South Africa; 4Francis Crick Institute Mill Hill Laboratory, and 5Department of Medicine, Imperial College London, United Kingdom (See the editorial commentary by Canaday and Toossi on pages 1292–3.) Human immunodeficiency virus type 1 (HIV) infection increases tuberculosis susceptibility [1] to such a great extent that tuberculosis is the leading cause of death of HIV–infected persons [2]. In 2013, an estimated 1.1 million new cases of tuberculosis and more than half (360 000) of all tuberculosisassociated deaths (500 000) occurred in coinfected persons [1]. These HIV-associated deaths and high incidence rates of tuberculosis occur despite the availability of antiretroviral therapy (ART) and tuberculosis preventive therapy. This demonstrates a need to understand better how HIV exacerbates tuberculosis immunopathology. The reduction of the number of peripheral CD4+ T cells associated with HIV progression correlates with increased tuberculosis susceptibility. However a considerable increase in susceptibility occurs even prior to substantial peripheral CD4+ Received 14 January 2016; accepted 16 June 2016; published online 26 July 2016. Correspondence: C. R. Diedrich (). The Journal of Infectious Diseases® 2016;214:1309–18 © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: 10.1093/infdis/jiw313 T-cell depletion and remains high in persons receiving antiretroviral therapy (ART) with no detectable viremia [3], suggesting that depletion of peripheral CD4+ T-cell counts and high viral load are not the only factors involved in increasing tuberculosis susceptibility. HIV–mediated destruction of CD4+ T cells is important to tuberculosis pathology because these cells are necessary for the appropriate response to M. tuberculosis [4, 5]. HIV also leads to a reduction in ex vivo peripheral [6, 7] and airway [8, 9] T-cell cytokine production following M. tuberculosis antigen stimulation. HIV infection has also been shown in vitro to increase the growth of M. tuberculosis in coinfected macrophages [10, 11], but such responses are highly variable [12]. Although these studies demonstrate that HIV causes specific reductions in the immunological responses to M. tuberculosis, very few studies have clearly demonstrated how HIV changes these responses within granulomas [13], the archetypal microscopic hallmark of tuberculosis-diseased tissue. The immunological function and cellular composition of granulomas significantly varies between granulomas [14] and blood or airways [15], demonstrating the need to examine granulomas directly [16]. M. tuberculosis granulomas function as organized immunological barriers that can prevent M. tuberculosis dissemination HIV and Tuberculosis-Associated Granulomas • JID 2016:214 (1 November) • 1309 Background. Human immunodeficiency virus type 1 (HIV)–infected persons are more susceptible to tuberculosis than HIV– uninfected persons. Low peripheral CD4+ T-cell count is not the sole cause of higher susceptibility, because HIV–infected persons with a high peripheral CD4+ T-cell count and those prescribed successful antiretroviral therapy (ART) remain more prone to active tuberculosis than HIV–uninfected persons. We hypothesized that the increase in susceptibility is caused by the ability of HIV to manipulate Mycobacterium tuberculosis–associated granulomas. Methods. We examined 71 excised cervical lymph nodes (LNs) from persons with HIV and M. tuberculosis coinfection, those with HIV monoinfection, and those with M. tuberculosis monoinfection with a spectrum of peripheral CD4+ T-cell counts and ART statuses. We quantified differences in M. tuberculosis levels, HIV p24 levels, cellular response, and cytokine presence within granulomas. Results. HIV increased M. tuberculosis numbers and reduced CD4+ T-cell counts within granulomas. Peripheral CD4+ T-cell depletion correlated with granulomas that contained fewer CD4+ and CD8+ T cells, less interferon γ, more neutrophils, more interleukin 10 (IL-10), and increased M. tuberculosis numbers. M. tuberculosis numbers correlated positively with IL-10 and interferon α levels and fewer CD4+ and CD8+ T cells. ART reduced IL-10 production. Conclusions. Peripheral CD4+ T-cell depletion correlated with increased M. tuberculosis presence, increased IL-10 production, and other phenotypic changes within granulomas, demonstrating the HIV infection progressively changes these granulomas. Keywords. HIV; tuberculosis; granuloma; mycobacterium; coinfection; histology; lymph node; antiretroviral therapy; IL-10. 1310 • JID 2016:214 (1 November) • Diedrich et al METHODS Study Approval This study was performed using excised cervical LN tissue stored within the Department of Anatomical Pathology at Groote Schuur Hospital (Cape Town, South Africa). All biopsy specimens were collected for clinical indications. Residual paraffinembedded blocks of these specimens were stored for further processing. This study complied with the declaration of Helsinki (2008), and ethics approval was obtained from the University of Cape Town Human Research Ethics Committee (REC187/2013). Informed consent was waived, as this was a retrospective study of FFPE tissue samples collected during the course of routine clinical practice. Patient identifiers were unavailable to investigators. Patient Selection The study group comprised persons who had undergone cervical LN biopsy between 2008 and 2013 and subsequently received a diagnosis of tuberculous lymphadenitis or an HIV diagnosis (for the HIV-mono-infected control group). Clinical case notes and pathology results were reviewed for demographic, clinical, pathologic, and microbiologic details for each individual identified. Patients were included if they had a diagnosis of tuberculosis lymphadenitis either via microbiological confirmation or if histologic findings and clinical picture were both consistent with the diagnosis. M. tuberculosis was directly identified within LNs by culture (based on detection of colony-forming units [CFU]), acid-fast bacilli (AFB) staining, or polymerase chain reaction (PCR) in 14 of 15 M. tuberculosis–m (...truncated)