DataSheet_1.docx

Mycobacterium tuberculosis Infections in Solid Organ Transplantation

miRNAs in immune responses to Mycobacterium tuberculosis infection

Lipoarabinomannan, and its related glycolipids, induce divergent and opposing immune responses to Mycobacterium tuberculosis depending on structural diversity and experimental variations

Human immune response mechanisms are crucial in the control of Mycobacterium tuberculosis (Mtb) infection. Understanding the human immune mechanisms and Mtb dynamics will assist in understanding the occurrence of different clinical outcomes experienced by individuals infected with Mtb. This work elaborates the role of dendritic cells (DCs) and other immune mechanisms in Mtb infection. We develop a model to predict disease progression scenarios, that is latency or active disease. Model analysis shows that occurrence of active disease is much attributed to the Mtb pathogen's ability to persist outside the intracellular environment and that strong immune response results in latent TB while relatively weak immune response result in active tuberculosis (TB). Our numerical results show that DCs recruitment, antigen (Ag) uptake and maturation affect the priming of the immune response and T cells levels at the site of infection. This study shows the crucial link between the innate immune mechanisms and the adaptive immune mechanisms. It also suggests directions for further basic studies and potential new treatment strategies.

IntroductionThe rising prevalence of Diabetes mellitus (DM) in high TB‐endemic countries may adversely affect sustainability of TB control since DM constitutes a risk factor for development of active tuberculosis (TB). The impact of DM on TB specific adaptive immune responses remains poorly addressed, particularly in people living in Sub‐Saharan countries. We performed a functional characterization of TB specific cellular immune response in Tanzanian subjects with active or latent Mycobacterium tuberculosis (Mtb) infection stratified by their diabetic status.MethodsHIV negative active TB patients (≥18 years) with Xpert MTB/RIF positive pulmonary TB were included before starting TB treatment in Dar es Salaam, Tanzania between April and December 2013. HIV negative healthy controls latently infected with TB but without past TB history were also included. Active and latent TB patients were stratified in two groups according to their diabetic status. Peripheral Blood Mononuclear cells were stimulated with either live M. bovis BCG or Mtb‐specific peptide pools and analyzed by intracellular cytokine staining and polychromatic flow cytometry.ResultsOur results show a lower frequency of IFN‐γ CD4+ T cells in patients with active TB and DM compared to patients with active TB only after live M. bovis BCG (p = 0.04) but not after Mtb peptide pools re‐stimulation. Irrespective of TB status, level of glycaemia is selectively inversely correlated with IFN‐γ and TNF‐α CD4+ T cell production (p = 0.02 and p = 0.03) after live M. bovis BCG stimulation.ConclusionsThese results support the hypothesis that hyperglycaemia negatively impacts antigen processing and/or presentation of whole mycobacteria delaying secretion of key cytokines involved in TB immunity.

Differentiating between active and latent tuberculosis with chest computed tomography

CD4 Tcells are rapidly depleted from tuberculosis granulomas following acute SIV co-infection.

BackgroundIL-17 and IL-22 cytokines play an important role in protective immune responses against Mycobacterium tuberculosis (Mtb) infection. Information on the production of these cytokines and the factors that regulate their production in the context of human immunodeficiency virus (HIV) and latent tuberculosis infection (LTBI) or active tuberculosis disease (ATB) is limited. In the current study, we compared the production of these two cytokines by PBMC of HIV-LTBI+ and HIV + LTBI+ individuals in response to Mtb antigens CFP-10 (culture filtrate protein) and ESAT-6 (Early Secretory Antigenic Target). We also determined the mechanisms involved in their production.MethodsWe cultured Peripheral Blood Mononuclear Cells (PBMCs) from HIV- individuals and HIV+ patients with latent tuberculosis and active disease with CFP-10 and ESAT-6. Production of IL-17, IL-22 and PD1 (Programmed Death 1), ICOS (Inducible T-cell Costimulator), IL-23R and FoxP3 (Forkhead box P3) expression on CD4+ T cells was measured.ResultsIn response to Mtb antigens CFP-10 and ESAT-6, freshly isolated PBMCs from HIV+ LTBI+ and HIV+ active TB patients produced less IL-17 and IL-22 and more IL-10, expressed less IL-23R, and more PD1 and expanded to more FoxP3+ cells. Active TB infection in HIV+ individuals further inhibited antigen specific IL-17 and IL-22 production compared to those with LTBI. Neutralization of PD1 restored IL-23R expression, IL-17 and IL-22 levels and lowered IL-10 production and reduced expansion of FoxP3 T cells.ConclusionsIn the current study we found that increased PD1 expression in HIV + LTBI+ and HIV+ active TB patients inhibits IL-17, IL-22 production and IL-23R expression in response to Mtb antigens CFP-10 and ESAT-6.

We read with interest the letter to the editor titled “How well do you know your monkey model” (1), written in response to our review article “The nonhuman primate model of tuberculosis” (J Med Primatol 41: 191–201) (2). This letter, by Engels and colleagues, raises an important issue about the use of the tuberculin skin test (TST) to detect Mycobacterium tuberculosis (Mtb) infection in nonhuman primates (NHPs). While we tend to agree with their general philosophy that improved detection of tuberculosis (TB), in particular latent TB, requires the development of more robust technologies, their understanding of our model is inherently flawed. The authors take for granted that all NHPs used in biomedical research are imported from nondomestic source countries. This is just not the case. The source of all Indian origin rhesus macaques in the US since the late 1970s has been from domestic breeding colonies. This was necessitated by a global ban on the export of Indian rhesus macaques by the government of India at that time. Since then, all Indian origin rhesus macaques at the NPRCs have been domestically bred and the animals are extremely well characterized with respect to infectious diseases such as tuberculosis (TB). As the authors state, rigorous preventive medicine programs have focused on maintaining negative TB status in domestic NHP colonies for many years. The authors are correct that the highest risk of TB infection in NHP occurs in animals imported from nondomestic sources. As a result, a best practice with respect to such animals is to keep them completely segregated from domestically bred NHPs. NHP originating from areas where TB is prevalent in the human population are extensively screened prior to inclusion at these NPRCs, or not used for TB research studies. Well-characterized domestic sources of NHP or NHP imported from areas without endemic TB are considered for these particular studies. It is the result of these strategies, that no TB outbreak has been detected at the TNPRC amongst domestically bred macaques, for more than two decades now. The author’s contention that “TST commonly fails to detect infection” is an overstatement, at least with respect to rhesus macaques. In an outbreak at the TNPRC close to 10 years ago in imported Chinese origin rhesus monkeys, the TST was diagnostic and was the screening method used to effectively identify cases and contain infection to a single room. Admittedly, adding other testing modalities increased our ability to confirm the diagnosis in this particular group of animals. The relatively low incidence of spontaneous TB cases in the literature compared to the number of domestic NHP used in research is a testament to the effectiveness of the TST used as a screening tool. If the TST “commonly” failed to detect cases of TB in domestic breeding colonies these colonies would have a much greater prevalence of disease than is currently noted. This contention is also supported by experimental data. In almost 125 Indian rhesus macaques experimentally infected since 2005, with Mtb CDC1551, H37Rv, Erdman or defined mutants of Mtb (3–8, unpublished results), here at the TNPRC, TST was able to detect Mtb infection. In many of these studies, which involved a vaccination component (6–8), TST always detected vaccination with BCG as well. In fact, we found no difference in the ability of TST and PRIMAGAM® (an interferon-gamma release assay comparable to QUANTIFERON-GOLD®) to detect experimental Mtb infection in domestically bred Indian rhesus at identical time-points. There is no argument that better TB diagnostic assays need to be developed and that the TST is far from a perfect screening tool. This is the driving force behind the development of nucleic acid based diagnostic tests for detecting human infections. However, the enthusiasm for such tests is dampened by the requirement for technology and infrastructure in resource-limited settings.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) infection, remains a global health threat despite recent advances and insights into host-pathogen interactions and the identification of diverse pathways that may be novel therapeutic targets for TB treatment. In addition, the emergence and spread of multidrug-resistant Mtb strains led to a low success rate of TB treatments. Thus, novel strategies involving the host immune system that boost the effectiveness of existing antibiotics have been recently suggested to better control TB. However, the lack of comprehensive understanding of the immunomodulatory effects of anti-TB drugs, including first-line drugs and newly introduced antibiotics, on bystander and effector immune cells curtailed the development of effective therapeutic strategies to combat Mtb infection. In this review, we focus on the influence of host immune-mediated stresses, such as lysosomal activation, metabolic changes, oxidative stress, mitochondrial damage, and immune mediators, on the activities of anti-TB drugs. In addition, we discuss how anti-TB drugs facilitate the generation of Mtb populations that are resistant to host immune response or disrupt host immunity. Thus, further understanding the interplay between anti-TB drugs and host immune responses may enhance effective host antimicrobial activities and prevent Mtb tolerance to antibiotic and immune attacks. Finally, this review highlights novel adjunctive therapeutic approaches against Mtb infection for better disease outcomes, shorter treatment duration, and improved treatment efficacy based on reciprocal interactions between current TB antibiotics and host immune cells.

Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis (TB), has killed nearly one billion people in the last two centuries. Nowadays, TB remains a major global health problem, ranking among the thirteen leading causes of death worldwide. Human TB infection spans different levels of stages: incipient, subclinical, latent and active TB, all of them with varying symptoms, microbiological characteristics, immune responses and pathologies profiles. After infection, Mtb interacts with diverse cells of both innate and adaptive immune compartments, playing a crucial role in the modulation and development of the pathology. Underlying TB clinical manifestations, individual immunological profiles can be identified in patients with active TB according to the strength of their immune responses to Mtb infection, defining diverse endotypes. Those different endotypes are regulated by a complex interaction of the patient’s cellular metabolism, genetic background, epigenetics, and gene transcriptional regulation. Here, we review immunological categorizations of TB patients based on the activation of different cellular populations (both myeloid and lymphocytic subsets) and humoral mediators (such as cytokines and lipid mediators). The analysis of the participating factors that operate during active Mtb infection shaping the immunological status or immune endotypes of TB patients could contribute to the development of Host Directed Therapy.

Tuberculosis (TB) represents the largest cause of death in human immunodeficiency virus (HIV)-infected individuals in part due to HIV-related CD4+ T cell loss, rendering patients immunocompromised and susceptible to a loss of Mycobacterium tuberculosis control. However, in light of increasing data pointing to a role for humoral immunity in controlling M. tuberculosis infection, here, we aimed to define whether HIV infection also alters the humoral immune response in subjects with active and latent TB. We show that in the setting of active TB, HIV-positive individuals have significantly lower IgG responses to LAM and Ag85 than HIV-negative individuals. Furthermore, significant isotype/subclass-specific differences were frequently observed, with active TB, HIV-positive individuals demonstrating compromised antigen-specific IgM titers. HIV-infected individuals with active TB also exhibited a significant loss of influenza hemagglutinin- and tetanus toxoid-specific antibody titers at the isotype/subclass level, a symptom of broad humoral immune dysfunction likely precipitated by HIV infection. Finally, we illustrated that despite the influence of HIV infection, differences in M. tuberculosis-specific antibody profiles persist between latent and active TB disease. Taken together, these findings reveal significant HIV-associated disruptions of the humoral immune response in HIV/TB-coinfected individuals.IMPORTANCE TB is the leading cause of death from a single infectious agent globally, followed by HIV. Furthermore, TB represents the leading cause of death among people with HIV. HIV is known to cause severe defects in T cell immunity, rendering HIV/TB-coinfected individuals more susceptible to TB disease progression and complicating accurate TB disease diagnosis. Here, we demonstrate that HIV infection is additionally associated with severely compromised antibody responses, particularly in individuals with active TB. Moreover, despite the influence of HIV infection, antibody profiles still allow accurate classification of individuals with active versus latent TB. These findings reveal novel immunologic challenges associated with HIV/TB coinfection and additionally provide a basis with which to leverage the key antibody features identified to potentially combat TB globally via next-generation therapeutic or diagnostic design.

Serum vitamin D influences cellular immunity against Mycobacterium tuberculosis, particularly in under-five children. Vitamin D insufficiency and deficiency as well as tuberculosis (TB) are highly prevalent in Indonesia. This study described the association of serum vitamin D in the incidence of latent TB in under-five children with a history of close TB contact. This cross-sectional study examined 178 under-five children with a history of close TB contact, with 98 index cases from primary health care facilities in Padang. Latent TB was defined based on a positive tuberculin skin test. Serum vitamin D was determined using ELISA method. General characteristics for age, sex, socioeconomic status, contact score, BCG scars, and nutritional status were also collected. Of 168 eligible subjects, 40.5% had latent TB, however no differences between 'latent TB' and 'without latent TB' were observed in participant characteristics. Vitamin D deficiency, insufficiency, and sufficiency were observed in 23.3%, 43.5%, and 33.3% of children, respectively. In general, the 'latent TB' group had lower serum vitamin D than those in the 'without latent TB' group, stratified by age, contact score and nutritional status; however, significant differences were observed in children age <1 years (18.0±2.6 vs 31.2±10.5, respectively, p=0.013). Nevertheless, no associations between the two groups were observed using multivariate analysis. Vitamin D status was not associated with the incidence of latent TB among under-five children with a history of close TB contact, although this may not obtain in children aged <1 year old.

Tuberculosis (TB) is one of the most fatal infectious diseases and a leading cause of mortality, with 95% of these deaths occurring in developing countries. The causative agent, Mycobacterium tuberculosis (Mtb), has a well-established ability to circumvent the host’s immune system for its intracellular survival. microRNAs (miRNAs) are small, non-coding RNAs having an important function at the post-transcriptional level and are involved in shaping immunity by regulating the repertoire of genes expressed in immune cells. It has been established in recent studies that the innate immune response against TB is significantly regulated by miRNAs. Moreover, differential expression of miRNA in Mtb infection can reflect the disease progression and may help distinguish between active and latent TB infection (LTBI). These findings encouraged the application of miRNAs as potential biomarkers. Similarly, active participation of miRNAs in modulation of autophagy and apoptosis responses against Mtb opens an exciting avenue for the exploitation of miRNAs as host directed therapy (HDT) against TB. Nanoparticles mediated delivery of miRNAs to treat various diseases has been reported and this technology has a great potential to be used in TB. In reality, this exploitation of miRNAs as biomarkers and in HDT is still in its infancy stage, and more studies using animal models mimicking human TB are advocated to assess the role of miRNAs as biomarkers and therapeutic targets. In this review, we attempt to summarize the recent advancements in the role of miRNAs in TB as immune modulator, miRNAs’ capability to distinguish between active and latent TB and, finally, usage of miRNAs as therapeutic targets against TB.

German S3-Guideline on the treatment of Psoriasis vulgaris, adapted from EuroGuiDerm - Part 2: Treatment monitoring and specific clinical or comorbid situations.