Transcriptome analysis of long non-coding RNAs in Mycobacterium avium complex-infected macrophages.

Mycobacterium avium complex (MAC) is a non-tuberculous mycobacterium widely distributed in the environment. Even though MAC infection is increasing in older women and immunocompromised patients, to our knowledge there has been no comprehensive analysis of the MAC-infected host-cell transcriptome-and particularly of long non-coding RNAs (lncRNAs). By using in vitro-cultured primary mouse bone-marrow-derived macrophages (BMDMs) and Cap analysis of gene expression, we analyzed the transcriptional and kinetic landscape of macrophage genes, with a focus on lncRNAs, during MAC infection. MAC infection of macrophages induced the expression of immune/inflammatory response genes and other genes similar to those involved in M1 macrophage activation, consistent with previous reports, although Nos2 (M1 activation) and Arg1 (M2 activation) had distinct expression profiles. We identified 31 upregulated and 30 downregulated lncRNA promoters corresponding respectively to 18 and 26 lncRNAs. Upregulated lncRNAs were clustered into two groups-early and late upregulated-predicted to be associated with immune activation and the immune response to infection, respectively. Furthermore, an Ingenuity Pathway Analysis revealed canonical pathways and upstream transcription regulators associated with differentially expressed lncRNAs. Several differentially expressed lncRNAs reported elsewhere underwent expressional changes upon M1 or M2 preactivation and subsequent MAC infection. Finally, we showed that expressional change of lncRNAs in MAC-infected BMDMs was mediated by toll-like receptor 2, although there may be other mechanisms that sense MAC infection. We identified differentially expressed lncRNAs in MAC-infected BMDMs, revealing diverse features that imply the distinct roles of these lncRNAs in MAC infection and macrophage polarization.

Attenuated tuberculin skin test responses associated with Mycobacterium intracellulare sputum colonization in an adolescent TB prevalence survey in Western Kenya.

INTRODUCTION: Exposure to Non-tuberculous Mycobacteria (NTM) varies regionally and may partly explain the disparate outcomes of BCG vaccination and tuberculosis (TB) susceptibility. METHODS: We examined NTM sputum colonization, associations with clinical characteristics, and tuberculin skin test (TST) responses in an adolescent TB prevalence survey. RESULTS: Among 5004 adolescents screened, 2281 (45.5 %) were evaluated further. TB and NTM prevalence rates were 0.3 % and 8.0 %, respectively. Among 418 NTM isolates, 103 were unidentifiable, and 315 (75 %) comprised 15 species, the most frequent being M. intracellulare (MAC) (108, 26 %), M. scrofulaceum (96, 23 %) and M. fortuitum (51, 12 %). "NTM colonized" adolescents had less frequent chronic cough and night sweats (adjusted odds ratio [aOR] 0.62, 95 % confidence interval [CI] 0.44-0.87and aOR 0.61, CI 0.42-0.89 respectively), and lower TST induration (median 11 mm (interquartile range [IQR] 0-16) vs 13 mm (IQR 6-17; p = 0.006)) when compared to "NTM not colonized" participants. MAC, but not M. scrofulaceum or M. fortuitum, was associated with decreased TST induration (median 7.5 mm (IQR 0-15) vs 13 mm (IQR 6-17) among "MAC colonized" vs "not colonized", p = 0.001). CONCLUSION: We observed high NTM prevalence rates with species-specific associations with TST induration, consistent with a model of species-dependent heterologous immunity among mycobacteria.

Recurrent disseminated Mycobacterium avium in a female patient from Thailand with anti-interferon-gamma autoantibodies: dilemma on treatment approach.

Anti-interferon-gamma (IFN-γ) autoantibodies has been recognised as an adult-onset immunodeficiency in the past decade in people who originate from Southeast Asia. These patients are susceptible to particular opportunistic infections, especially non-tuberculous mycobacteria (NTM). We present the case of a woman whom originally came from Thailand with disseminated Mycobacterium avium complex infection (pleural, pericardium, bloodstream and lung parenchymal involvement). Her infection continued to progress while receiving proper antibiotic treatment. Once high titre neutralising anti-IFN-γ autoantibodies were detected, rituximab was added as adjunctive treatment. The patient had remarkable clinical improvement against persistence of anti-IFN-γ autoantibodies. Although her lung disease has improved, the patient continues on triple therapy for NTM. The kinetics of anti-IFN-γ autoantibodies in the context of clinical progression, indication and length for rituximab and triple therapy is discussed in view of the current literature.

Mycobacterial immunevasion-Spotlight on the enemy within.

Discussion on how antibiotic treatment routes Mycobacterium avium to phagolysosomes without eliciting an immune response in human macrophages.

Evaluation of plasma anti-GPL-core IgA and IgG for diagnosis of disseminated non-tuberculous mycobacteria infection.

Detection of IgA antibody against Mycobacterium avium complex (MAC) glycopeptidolipid (GPL) has recently been shown to improve the diagnosis of MAC pulmonary disease but has yet to be tested in disseminated Non-tuberculous mycobacteria (NTM) infection. In this study, we address the diagnostic efficacies of an anti-GPL-core ELISA kit in disseminated lymphadenopathy patients positive for NTM culture and anti-IFN-γ autoantibodies. The study was conducted in a tertiary referral center in northeastern Thailand and patients with NTM, tuberculosis, melioidosis, and control subjects were enrolled. Plasma immunoglobulin A (IgA) and G (IgG) antibodies against GPL-core were detected in the subjects and the specificity and sensitivity of the assay was assessed. Anti-GPL-core IgA and IgG levels were significantly higher in NTM patients than other groups (p < 0.0001). Diagnostic efficacy for NTM patients using anti-GPL-core IgA cut-off value of 0.352 U/ml showed good sensitivity (91.18%) and intermediate specificity (70.15%). Using a cut-off value of 4.140 AU/ml for anti-GPL-core IgG showed the same sensitivity (91.18%) with increased specificity (89.55%) and an 81.58% positive predictive value. Most patients with moderate levels (4.140-7.955 AU/ml) of anti-GPL-core IgG had rapidly growing mycobacteria (RGM) infection. Taken together, the detection of anti-GPL-core antibodies could provide a novel option for the diagnosis and management of disseminated NTM infected patients.

Transient Decrease of Circulating and Tissular Dendritic Cells in Patients With Mycobacterial Disease and With Partial Dominant IFNγR1 Deficiency.

Interferon-γ receptor 1 (IFNγR1) deficiency is one of the inborn errors of IFN-γ immunity underlying Mendelian Susceptibility to Mycobacterial Disease (MSMD). This molecular circuit plays a crucial role in regulating the interaction between dendritic cells (DCs) and T lymphocytes, thus affecting DCs activation, maturation, and priming of T cells involved in the immune response against intracellular pathogens. We studied a girl who developed at the age of 2.5 years a Mycobacterium avium infection characterized by disseminated necrotizing granulomatous lymphadenitis, and we compared her findings with other patients with the same genetic condition. The patient carried a heterozygous 818del4 mutation in the IFNGR1 gene responsible of autosomal dominant (AD) partial IFNγR1 deficiency. During the acute infection blood cells immunophenotyping showed a marked reduction in DCs counts, including both myeloid (mDCs) and plasmacytoid (pDCs) subsets, that reversed after successful prolonged antimicrobial therapy. Histology of her abdomen lymph node revealed a profound depletion of tissue pDCs, as compared to other age-matched granulomatous lymphadenitis of mycobacterial origin. Circulating DCs depletion was also observed in another patient with AD partial IFNγR1 deficiency during mycobacterial infection. To conclude, AD partial IFNγR1 deficiency can be associated with a transient decrease in both circulating and tissular DCs during acute mycobacterial infection, suggesting that DCs counts monitoring might constitute a useful marker of treatment response.

POPS case: A 30-year-old Filipino woman with fevers, lymphadenopathy, painful scalp lesions, and a neck mass.

We described a case of a 30-year-old Filipino woman who presented with fevers, night sweats, left hip pain, painful scalp lesions, and a neck mass. Symptoms began 6 months earlier, with nasal drainage, fever, cough, and occasional hemoptysis, which did not resolve with outpatient antibiotics. A further workup revealed lymphadenopathy and several lytic bone lesions. Her hospital course was later further complicated by the development of a tracheoesophageal fistula secondary to an esophageal mass and, then later, aseptic meningitis. Extensive diagnostic workup and immunologic tests were performed and finally led to the diagnosis. Here, we discussed the diagnostic workup and pathophysiology of the underlying condition. This case illustrated the importance of appropriate immunologic workup to make the diagnosis of a rare condition that proves to be clinically significant and presents challenges in management.

Serum immunoglobulin a antibodies to glycopeptidolipid core antigen for Mycobacteroides abscessus complex lung disease.

Background: Mycobacteroides abscessus complex (MABC) exhibits smooth morphotypes, expressing glycopeptidolipid (GPL), and rough morphotypes, expressing diminished GPL, on the MABC cell wall. Few reports have focused on the relationship between anti-GPL-core immunoglobulin A (IgA) antibody and colony morphology in MABC lung disease. Methods: This study aimed to test GPL core antigen in patients with MABC lung disease to investigate the relationship between coinfection/contamination in other nontuberculous mycobacteria species and colony morphology variant in MABC isolates. Patients with MABC lung disease and contamination diagnosed between 2012 and 2017 at our hospital were enrolled retrospectively. Results: Of the assessed patients, 43 patients with MABC lung disease and 13 with MABC contamination were included. There was a significant difference in anti-GPL-core IgA antibody levels between them (P = 0.02). Forty-three patients with MABC lung disease were divided into two groups as positive and negative antibodies groups. A significant increase in the positive anti-GPL-core IgA antibody was observed in coexistence with both Mycobacterium avium complex (MAC) (P = 0.02) and the isolate of the smooth variant (P = 0.03) in MABC. Conclusions: Anti-GPL-core IgA antibodies in patients with MABC are greatly influenced by MAC coexistence, and colony morphology variant of the MABC isolate.

Different clinical features of patients with pulmonary disease caused by various Mycobacterium avium-intracellulare complex subspecies and antimicrobial susceptibility.

OBJECTIVES: Characteristics of the Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) caused by distinct subspecies remain uncertain. METHODS: This study was conducted from 2013-2015 in three hospitals in Taiwan. RESULTS: Among the 144 patients with MAC-PD, 57 (39.6%), 37 (25.7%), 37 (25.7%), and 13 (9.0%) were infected with Mycobacterium intracellulare subspecies intracellulare (MIsI), Mycobacterium avium subspecies hominissuis (MAsH), Mycobacterium intracellulare subspecies chimaera (MIsC), and others, respectively. Patients with MAsH-PD were younger (p = 0.010) with higher human immunodeficiency virus infection rates (27.0%, 0.0%, 0.0%, and 7.7% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p < 0.001). Twenty-two (15.3%) patients reported spontaneous culture-negative conversion, but 15 (10.4%) and 33 (22.9%) patients developed radiographic progression and unfavorable outcomes, especially MAsH-PD. The susceptibility rates to clarithromycin and inhaled amikacin were both 98.6%. MAsH demonstrated the lowest rate of resistance to moxifloxacin (66.7%, 97.3%, 89.1%, and 92.3% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p = 0.001) and MIsI isolates had the highest rate of resistance to intravenous amikacin (25%, 13.5%, 38.2%, and 15.4% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p = 0.024). CONCLUSIONS: Pulmonary disease caused by distinct MAC subspecies had different outcomes and drug susceptibility. The local prevalence of species needs to be monitored.

A 71-year-old man with recurrent pulmonary mycobacterial avium complex infections and lymphopenia.

Mycobacterium avium complex (MAC) infections, generally viewed as opportunistic infections, often trigger an evaluation for an underlying immunodeficiency disorder. However, MAC infections can occur in patients who presumably are immunocompetent, particularly in those with an underlying structural lung disease. T-cell immunity plays a critical role in controlling MAC infection. We presented a case of lymphopenia, which complicated the clinical course of a pulmonary MAC infection in a patient who was negative for human immunodeficiency virus.

The New Frontier of Host-Directed Therapies for Mycobacterium avium Complex.

Mycobacterium avium complex (MAC) is an increasingly important cause of morbidity and mortality, and is responsible for pulmonary infection in patients with underlying lung disease and disseminated disease in patients with AIDS. MAC has evolved various virulence strategies to subvert immune responses and persist in the infected host. Current treatment for MAC is challenging, requiring a combination of multiple antibiotics given over a long time period (for at least 12 months after negative sputum culture conversion). Moreover, even after eradication of infection, many patients are left with residual lung dysfunction. In order to address similar challenges facing the management of patients with tuberculosis, recent attention has focused on the development of novel adjunctive, host-directed therapies (HDTs), with the goal of accelerating the clearance of mycobacteria by immune defenses and reducing or reversing mycobacterial-induced lung damage. In this review, we will summarize the evidence supporting specific adjunctive, HDTs for MAC, with a focus on the repurposing of existing immune-modulatory agents targeting a variety of different cellular pathways. We also highlight areas meriting further investigation.

Aortic Graft Infection With Mycobacterium Avium Complex.

Aortic graft infections are uncommon complications after endovascular aortic surgery. In the majority of cases, gram-positive and then gram-negative organisms are the causative agents leading to this condition. Atypical organisms are traditionally not responsible for graft infection unless the patient is immunocompromised. We are reporting a case of culture-confirmed mycobacterium avium complex infection of an aortic graft in a well-controlled patient with HIV who had an undetected viral load and a CD4 count of 324 while on highly active antiretroviral therapy.

NLRP3 inflammasome is attenuated in patients with Mycobacterium avium complex lung disease and correlated with decreased interleukin-1ß response and host susceptibility.

The incidence of nontuberculous mycobacteria lung disease (NTM-LD) is increasing in patients without human immunodeficiency virus. Mycobacterium avium complex (MAC) is one of the most common pathogenic species. The presence of MAC has a clinical relevance of around 35~42%, indicating the possibility of host susceptibility. Previous studies have shown that interleukin (IL)-1ß and IL-1-receptor knock-out mice are susceptible to mycobacterial infections; however, the role of inflammasome-driven interleukin (IL)-1ß has not been studied in MAC-LD. We enrolled patients with MAC-LD and healthy controls. Peripheral blood mononuclear cells (PBMCs), monocytes, and monocyte-derived macrophages were stimulated by MAC bacilli. The responses of interleukin(IL)-1ß and the expression of inflammasome and toll-like receptors (TLRs) were measured. Single nucleotide polymorphisms (SNPs) were also examined for NLRP3 and TLR2 genes. In the patients with MAC-LD, the IL-1ß responses decreased in PBMCs, monocytes, and macrophages assayed by MAC bacilli in comparison to the healthy controls. In addition, the level of caspase-1 after stimulation was lower in the MAC-LD group, although the mRNA level of IL-1ß was not significantly lower. In surveying the activation of IL-1ß, the MAC-LD group had an attenuated mRNA level of NLRP3 but similar levels of AIM2 and ASC compared with the controls. The SNPs rs3806268 and rs34298354 in NLRP3 for females and rs3804100 in TLR2 for males were associated with MAC-LD. In conclusion, our patients with MAC-LD had attenuated IL-1ß production, which may have been due to lower activation of the NLRP3-caspase-1 axis. Two SNPs of NLRP3 and one of TLR2 were correlated with MAC-LD, possibly indicating host susceptibility.

Alpha-1-Antitrypsin Enhances Primary Human Macrophage Immunity Against Non-tuberculous Mycobacteria.

Rationale: The association between non-tuberculous mycobacterial lung disease and alpha-1-antitrypsin (AAT) deficiency is likely due, in part, to underlying emphysema or bronchiectasis. But there is increasing evidence that AAT itself enhances host immunity against microbial pathogens and thus deficiency could compromise host protection. Objectives: The goal of this project is to determine if AAT could augment macrophage activity against non-tuberculous mycobacteria. Methods: We compared the ability of monocyte-derived macrophages cultured in autologous plasma that were obtained immediately before and soon after AAT infusion-given to individuals with AAT deficiency-to control an ex vivo Mycobacterium intracellulare infection. Measurements and Main Results: We found that compared to pre-AAT infused monocyte-derived macrophages plus plasma, macrophages, and contemporaneous plasma obtained after a session of AAT infusion were significantly better able to control M. intracellulare infection; the reduced bacterial burden was linked with greater phagosome-lysosome fusion and increased autophagosome formation/maturation, the latter due to AAT inhibition of both M. intracellulare-induced nuclear factor-kappa B activation and A20 expression. While there was a modest increase in apoptosis in the M. intracellulare-infected post-AAT infused macrophages and plasma, inhibiting caspase-3 in THP-1 cells, monocyte-derived macrophages, and alveolar macrophages unexpectedly reduced the M. intracellulare burden, indicating that apoptosis impairs macrophage control of M. intracellulare and that the host protective effects of AAT occurred despite inducing apoptosis. Conclusion: AAT augments macrophage control of M. intracellulare infection through enhancing phagosome-lysosome fusion and autophagy.

Mycobacteria-Specific T Cells May Be Expanded From Healthy Donors and Are Near Absent in Primary Immunodeficiency Disorders.

Mycobacterial Infections can be severe in patients with T-cell deficiency or phagocyte disorders, and treatment is frequently complicated by antimicrobial resistance. Restoration of T-cell immunity via stem cell transplantation facilitates control of mycobacterial infections, but presence of active infections during transplantation is associated with a higher risk of mortality. Adoptive T cell immunotherapy has been successful in targeting viruses, but has not been attempted to treat mycobacterial infections. We sought to expand and characterize mycobacterial-specific T-cells derived from healthy donors in order to determine suitability for adoptive immunotherapy. Mycobacteria-specific T-cells (MSTs) were generated from 10 healthy donors using a rapid ex vivo expansion protocol targeting five known mycobacterial target proteins (AG85B, PPE68, ESXA, ESXB, and ADK). MSTs were compared to T-cells expanded from the same donors using lysate from M. tuberculosis or purified protein derivative from M. avium (sensitin). MST expansion from seven patients with primary immunodeficiency disorders (PID) and two patients with IFN-γ autoantibodies and invasive M. avium infections. MSTs expanded from healthy donors recognized a median of 3 of 5 antigens, with production of IFN-γ, TNF, and GM-CSF in CD4+ T cells. Comparison of donors who received BCG vaccine (n = 6) to those who did not (n = 4) showed differential responses to PPE68 (p = 0.028) and ADK (p = 0.015) by IFN-γ ELISpot. MSTs expanded from lysate or sensitin also recognized multiple mycobacterial antigens, with a statistically significant differences noted only in the response to PPE68 (p = 0.016). MSTs expanded from patients with primary immunodeficiency (PID) and invasive mycobacterial infections showed activity against mycobacterial antigens in only two of seven subjects, whereas both patients with IFN-γ autoantibodies recognized mycobacterial antigens. Thus, MSTs can be generated from donors using a rapid expansion protocol regardless of history of BCG immunization. Most tested PID patients had no detectable T-cell immunity to mycobacteria despite history of infection. MSTs may have clinical utility for adoptive immunotherapy in T-cell deficient patients with invasive mycobacterial infections.

Multiplex cytokine analysis in Mycobacterium avium complex lung disease: relationship between CXCL10 and poor prognostic factors.

BACKGROUND: Mycobacterium avium complex lung disease (MAC-LD) can deteriorate rapidly to become fatal. Reported poor prognostic factors include radiographic findings, undernutrition, anemia and high inflammation test values. However, the association of these prognostic factors with the pathophysiology of the disease remains unknown. We aimed to clarify the pathophysiology of MAC-LD and develop a new biomarker that reflects the immune response to the disease. METHODS: We performed the cytokine panel analyses of serum from patients with MAC-LD and compared each cytokine level with clinically negative prognostic factors (radiographic disease type, body mass index, albumin, C-reactive protein and hemoglobin) and high-resolution CT scores. RESULTS: We analyzed 27 patients with MAC-LD, 6 with the fibrocavitary form and 21 with the nodular bronchiectatic form on high-resolution CT. Serum CXC motif ligand 10 (CXCL10) concentration was significantly elevated in patients with the fibrocavitary form (p = 0.008). CXCL10 levels correlated with body mass index (r = - 0.60, p = 0.0008), serum albumin concentration (r = - 0.45, p = 0.016) and high-resolution CT scores (r = 0.61, p = 0.0006). Among 14 patients initially untreated, antibiotic therapy was initiated for five during the study period. CXCL10 concentration was significantly higher in these patients (p = 0.046), and receiver operating characteristic analysis for CXCL10 concentration on treatment initiation produced an area under the curve of 0.844, with a sensitivity of 100%, specificity of 66.7%, and cut-off value of 366.5 pg/mL. CONCLUSION: We revealed cytokine profiles in patients with MAC-LD. Serum CXCL10 levels probably reflect the severity of MAC-LD. Our findings suggest that CXCL10 concentration may be a promising biomarker for managing treatment for patients with MAC disease of the lung.

A rare case of disseminated Mycobacterium avium complex with colitis in a renal transplant recipient.

Mycobacterium avium complex (MAC) colitis is a rare complication of immunosuppression in solid organ transplant (SOT) recipients. Here, we describe a case of disseminated MAC infection with colitis following renal transplantation. Despite common pathways of immunosuppression, SOT recipients and human immunodeficiency virus (HIV)-infected patients differ in their typical presentations of MAC infection. Intestinal infections have been more commonly reported in HIV-infected patients than in SOT recipients. The explanation for this difference may be related to HIV's targeted effects on the CD4+ T-cell reservoir in gut-associated lymphoid tissue.

Genitourinary Tract Infection Due to Mycobacterium avium intracellulare Complex Infection in Pretransplant Setting With Recurrence Following Transplant: A Case Report.

Genitourinary (GU) tract infection with Mycobacterium avium intracellulare complex (MAI) is very rare and, to our knowledge, has never been reported in the solid organ transplant literature. CASE DESCRIPTION: A 61-year-old Somali-born woman had a history of liver cirrhosis due to chronic hepatitis C infection. She was diagnosed as having and treated for latent tuberculosis infection and GU tract infection due to MAI. She received a total of 17 months antimycobacterial therapy consisting of azithromycin, ethambutol, and moxifloxacin. Within 5 months of the initiation of antimicrobial therapy, there was documented sterilization of urine mycobacterial cultures. Liver and kidney transplant was performed 3 months after finishing the treatment course. One year following transplant, GU tract infection due to MAI recurred. She declined further diagnostic testing as well as mycobacterial therapy. She died 15 months following transplant for reasons not related to infections. CONCLUSION: The treatment of MAI infection in solid organ transplant candidates and recipients is challenging, and the duration of therapy in this population is not known. The recurrence of infection following transplant in this case may argue in favor of a duration that extends beyond the date of transplant. The combination of a fluoroquinolone and ethambutol may successfully prevent reactivation of tuberculosis in patients with history of latent tuberculosis infection and deserves further evaluation.

Mycobacterium indicus pranii protein MIP_05962 induces Th1 cell mediated immune response in mice.

Utility of Mycobacterium indicus pranii (MIP) as a multistage vaccine against mycobacterial infections demands identification of its protective antigens. We explored antigenicity and immunogenicity of a candidate protein MIP_05962 that depicts homology to HSP18 of M. leprae and antigen1 of Mycobacterium tuberculosis. This protein elicited substantial antibody response in immunized mice along with modulation of cellular immune response towards protective Th1 type. Both CD4+ and CD8+ subsets from immunized mice produced hallmark protective cytokines, IFN-γ, TNF-α and IL-2. This protein also enhanced the CD4+ effector memory that could act as first line of defence during infections. These results point to MIP_05962 as a protective antigen that contributes, in conjunction with others, to the protective immunity of this live vaccine candidate.