Pulmonary Granulomas Research Articles

TLR3 modulates immunopathology during a Schistosoma mansoni egg‐driven Th2 response in the lung

We examined the role of TLR3 in Th2-driven pulmonary granulomatous disease, using wildtype (TLR3(+/+)) and TLR3 gene-deficient (TLR3(-/-)) mice in a well-established model of Schistosoma mansoni egg-induced pulmonary granuloma. The intravenous bolus injection of S. mansoni eggs into S. mansoni-sensitized TLR3(+/+) mice was associated with an increase in TLR3 transcript expression in alveolar macrophages and ex vivo spleen and lung cultures at day 8 after egg injection. Lungs from TLR3(-/-) mice showed an increase in granuloma size, greater collagen deposition around the granuloma, and increased Th2 cytokine and chemokine levels compared with similarly sensitized and challenged TLR3(+/+) mice. Macrophages from TLR3(-/-) mice exhibited an M2 phenotype characterized by increased arginase and CCL2 expression. Significantly greater numbers of CD4(+)CD25(+) T cells were present in the lungs of TLR3(-/-) mice compared with TLR3(+/+) mice at day 8 after egg embolization. Cells derived from granulomatous lung and lung draining lymph nodes of TLR3(-/-) mice released significantly higher levels of IL-17 levels relative to TLR3(+/+) cells. Thus, our data suggest that TLR3 has a major regulatory role during a Th2-driven granulomatous response as its absence enhanced immunopathology.

The C-Type Lectin SIGNR1 BindsSchistosoma mansoniAntigens In Vitro, but SIGNR1-Deficient Mice Have Normal Responses during Schistosome Infection

The de novo immune response to infectious organisms arises from the innate recognition of pathogen-associated molecular patterns (PAMPs) by the host's pattern recognition receptors (PRRs). As the generation of type 2 cytokine responses by the human trematode parasite Schistosoma mansoni is glycan mediated, there is a particular potential role for a C-type lectin receptor (CLR) to mediate the innate recognition of schistosome PAMPs. One such CLR, dendritic cell-specific intracellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN; CD209), has been shown to recognize glycans expressed by S. mansoni eggs. We show that SIGNR1 (SIGN-related 1; CD209b), a murine homologue of DC-SIGN that is expressed on macrophages, also binds both schistosome-soluble egg antigens and worm antigens in vitro. The generation of schistosome egg-induced pulmonary egg granulomas was not altered in SIGNR1-deficient mice. Following S. mansoni infection, the SIGNR1-deficient mice had an unaltered phenotype with an intact immunological response and no difference in pathology. In this study we demonstrate that although SIGNR1 recognizes S. mansoni antigens in vitro, this CLR is redundant during infection. This study highlights the finding that although there was binding of SIGNR1 to immunogenic factors produced in the S. mansoni life cycle, this recognition does not translate to a functional in vivo role for the PRR during infection.

PULMONARY HYALINIZING GRANULOMA: APPEARANCE ON POSITRON EMISSION TOMOGRAPHY SCAN AND ASSOCIATION WITH DEEP VENOUS THROMBOSIS IN THE ABSENCE OF HYPERCOAGULABLE STATE

INTRODUCTION: Patients with Pulmonary Hyalinizing Granuloma (PHG) usually present with lung masses diagnosed incidentally on chest radiographs (CXR). However, their appearance on a 18-FDG Positron Emission Tomography (PET) scan in adults is not known and is reported here along with the association with deep venous thrombosis (DVT) in the absence of any pro-coagulant risk factors.

Induction of apoptosis and absence of inflammation in rat lung after intratracheal instillation of multiwalled carbon nanotubes

Several studies performed by intratracheal instillation showed that carbon nanotubes (CNT) induced pulmonary fibrosis, granulomas or inflammation. But, recently, two inhalation studies did not observed such pathological phenomena and suggest that granulomas could be due to the instillation of unbreathable agglomerates. In a previous study, we have described a simple method (using albumin as dispersing agent) which produced solutions containing more than 80% of agglomerate of breathable size. We report here results from intratracheal instillation of rats by 0, 1, 10 or 100 μg of MWCNT dispersed with albumin. After 1, 7, 30, 90, and 180 days, inflammation, apoptosis, fibrosis, respiratory parameters and granuloma formation were assessed. Results obtained by plethysmography, soluble collagen quantification, qRT-PCR and luminex measurement of cytokines expression and histopathological observation showed only evidence of apoptosis of alveolar macrophages. These result underline the importance of controlling MWCNT agglomerate size when exposing animals, through appropriate dispersion methods.

Adalimumab-induced noncaseating granuloma in the bone marrow of a patient being treated for rheumatoid arthritis

Sarcoidosis is a multisystemic disease characterized by noncaseating granulomatous infiltration, primarily of the lungs and lymphatic system. While reports of the efficacy of adalimumab in the treatment of refractory sarcoidosis have been mixed, the more widely used infliximab has demonstrated clear efficacy in this disease. The association between tumor necrosis factor (TNF)-inhibitors and noncaseating granulomas in the lung has been reported in literature. With the exception of one patient treated with adalimumab, who developed pulmonary granuloma, the remaining patients described in literature were treated with etanercept. The current case study is, to our knowledge, the first to describe adalimumab-induced noncaseating granulomas in the bone marrow of a patient being treated for rheumatoid arthritis and suggests that although TNF-inhibitors are used in the treatment of granulomatous disorders, their use should be carefully monitored as, in rare cases, TNF-inhibitors may leave sufficient cytokine activation to support granuloma formation.

Non-diagnosed pulmonary hyalinizing granuloma (PHG) as a cause of sudden unexpected death

Pulmonary hyalinizing granuloma (PHG), a very rare benign tumour of the lungs, was first reported in 1977. We present a PHG of a 32-year-old woman from Yemen who collapsed 1 day after her arrival in Germany. Tuberculosis was suspected and the health authorities nearly closed part of one of the major international airports in Europe. However, this drastic measure was avoided by autopsy and a correct interpretation of the solid-elastic and well-circumscribed lung tumour as not characteristic for tuberculosis. Although the final diagnosis of PHG was only achieved after histology, this case strongly illustrates the necessity of a profound morphological training of forensic physicians.

Granulomatous Pneumonia, Lymphadenopathy, and Hepatopathy in an Adult Horse with Repeated Injection of BCG

R. van den Boom, E.J.B. Veldhuis Kroeze, W.R. Klein, D.J. Houwers, A.G.M. van der Zanden, and M.M. Sloet van Oldruitenborgh-Oosterbaan

Pulmonary Mycobacterium tuberculosis (Beijing strain) infection in a stray dog : clinical communication

Mycobacterium tuberculosis infection in dogs is rarely reported and has not previously been documented in South Africa. A case of a stray Maltese crossbreed dog with extensive multifocal pulmonary tuberculosis due to M. tuberculosis is described. Pulmonary granulomas in this case were poorly encapsulated and contained large numbers of acid-fast bacteria, highlighting the potential for infected companion animals to excrete the pathogen. Treatment of canine tuberculosis is generally not advised, and for this reason, euthanasia of diseased animals must be advocated in most instances. Physicians and veterinarians must be aware that companion animals with active disease caused by M. tuberculosis could act as a potential source of infection.

RADIOGRAPHIC, COMPUTED TOMOGRAPHIC, AND ULTRASONOGRAPHIC FINDINGS WITH MIGRATING INTRATHORACIC GRASS AWNS IN DOGS AND CATS

The purpose of this study was to describe the clinical, radiographic, and computed tomographic findings in dogs and cats with migrating intrathoracic grass awns. Thirty-five dogs and five cats with visual confirmation of a grass awn following surgery, endoscopy or necropsy, and histology were assessed. The medical records and all diagnostic imaging studies were reviewed retrospectively. Labrador Retrievers or English Pointers < 5 years of age, with a history of coughing and hyperthermia, were the most common presentations. Seventeen animals had an inflammatory leukogram of which 14 had a left shift or toxic neutrophils. Radiographs were performed in 38 animals and computed tomography (CT) in 14. Thoracic radiographs were characterized by focal pulmonary interstitial to alveolar opacities (n = 26) that occurred most commonly in the caudal (n = 19) or accessory lobes (n = 8). Additional findings included pneumothorax (n = 9), pleural effusion (n = 8), and pleural thickening (n = 7). Pulmonary opacities identified on radiographs correlated to areas of pneumonia and foreign body location. CT findings included focal interstitial to alveolar pulmonary opacities (n = 12) most commonly in the right caudal lung lobe (n = 9), pleural thickening (n = 11), mildly enlarged intrathoracic lymph nodes (n = 10), soft tissue tracking (n = 7) with enhancing margins (n = 4), pneumothorax (n = 6), pleural effusion (n = 4), and foreign body visualization (n = 4). Histologic diagnoses included pulmonary and mediastinal granulomas or abscesses, bronchopneumonia, and pleuritis. Migrating intrathoracic grass awns should be considered as a differential diagnosis in coughing, febrile animals with focal interstitial to alveolar pulmonary opacities, pleural effusion, pleural thickening, and/or pneumothorax on radiographs or CT.

Tuberculous granulomas are hypoxic in guinea pigs, rabbits, and nonhuman primates.

Understanding the physical characteristics of the local microenvironment in which Mycobacterium tuberculosis resides is an important goal that may allow the targeting of metabolic processes to shorten drug regimens. Pimonidazole hydrochloride (Hypoxyprobe) is an imaging agent that is bioreductively activated only under hypoxic conditions in mammalian tissue. We employed this probe to evaluate the oxygen tension in tuberculous granulomas in four animal models of disease: mouse, guinea pig, rabbit, and nonhuman primate. Following infusion of pimonidazole into animals with established infections, lung tissues from the guinea pig, rabbit, and nonhuman primate showed discrete areas of pimonidazole adduct formation surrounding necrotic and caseous regions of pulmonary granulomas by immunohistochemical staining. This labeling could be substantially reduced by housing the animal under an atmosphere of 95% O(2). Direct measurement of tissue oxygen partial pressure by surgical insertion of a fiber optic oxygen probe into granulomas in the lungs of living infected rabbits demonstrated that even small (3-mm) pulmonary lesions were severely hypoxic (1.6 +/- 0.7 mm Hg). Finally, metronidazole, which has potent bactericidal activity in vitro only under low-oxygen culture conditions, was highly effective at reducing total-lung bacterial burdens in infected rabbits. Thus, three independent lines of evidence support the hypothesis that hypoxic microenvironments are an important feature of some lesions in these animal models of tuberculosis.

TLR9 activation is a key event for the maintenance of a mycobacterial antigen‐elicited pulmonary granuloma

We previously described a model of polarized Th1 cell‐mediated anamnestic pulmonary granulomatous inflammation in sensitized mice induced by pulmonary embolization of agarose beads coated with covalently bound antigens of Mycobacteria bovis purified protein derivative (PPD). We have also demonstrated TLR9 plays an important role in maintaining the appropriate phenotype in a Th1 granulomatous response. We demonstrate in this study that TLR9−/− mice showed greatly increased granuloma formation as assessed by impaired myeloid dendritic cells and increased regulatory T cells, and Th‐2 skewed cytokine profile compared with wild‐type. Moreover, the expression of Th17 cytokine family members (IL‐17 and IL‐21) was abrogated in TLR9−/− mice. These data also support the concept that dendritic cells, but not macrophages, from bone marrow can promote the differentiation of Th‐17 cells, while both macrophages and dendritic cells promote Th‐1 cell differentiation after BCG stimulation. These findings support the concept that the impaired recruitment of granuloma dendritic cells alters the Th17 cytokine profile in TLR9‐deficient mice.This work was supported by NIH grants HL031963, HL074024, and HL031237.

Single-Walled Carbon Nanotubes Can Induce Pulmonary Injury in Mouse Model

Carbon nanotubes are a nanomaterial that is extensively used in industry. The potential health risk of chronic carbon nanotubes exposure has been raised as of great public concern. In the present study, we have demonstrated that intratracheal instillation of 0.5 mg of single-walled carbon nanotubes (SWCNT) into male ICR mice (8 weeks old) induced alveolar macrophage activation, various chronic inflammatory responses, and severe pulmonary granuloma formation. We then used Affymetrix microarrays to investigate the molecular effects on the macrophages when exposed to SWCNT. A biological pathway analysis, a literature survey, and experimental validation suggest that the uptake of SWCNT into the macrophages is able to activate various transcription factors such as nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1), and this leads to oxidative stress, the release of proinflammatory cytokines, the recruitment of leukocytes, the induction of protective and antiapoptotic gene expression, and the activation of T cells. The resulting innate and adaptive immune responses may explain the chronic pulmonary inflammation and granuloma formation in vivo caused by SWCNT.

Lung granulomas from Mycobacterium tuberculosis/HIV-1 co-infected patients display decreased in situ TNF production

Tuberculosis/HIV-1 co-infection is responsible for thousands of deaths each year, and previous studies have reported that co-infected individuals display major morphological alterations in tissue granulomas. The purpose of this study was to evaluate immunohistopathological characteristics in lung tissues from pulmonary TB/HIV-1-co-infected individuals. Following autopsy, tuberculosis-positive HIV-1-negative cases displayed granulomas with normal architecture, mainly composed of a mononuclear infiltrate with typical epithelioid, as well as giant cells, and exhibiting caseous necrosis. In contrast, lesions from the TB/HIV-1-co-infected group showed extensive necrosis, poorly formed granulomas, and a marked presence of polymorphonuclear cells. More importantly, TNF staining was greatly reduced in the TB/HIV-1-co-infected individuals. Our data suggest that HIV-1 infection alters the organization of pulmonary granulomas by modulating TNF and, possibly, cell trafficking, leading to an impaired anti-tuberculosis response.

Gastrin-Releasing Peptide Receptor as a Molecular Target for Inflammatory Diseases

Bombesin-like peptides (BLP) and its receptors are widely distributed in mammalian peripheral tissues and in the central nervous system. Recently, effects of these peptides on the production and release of cytokines were described both in animal models and humans with inflammatory diseases. Some pathological conditions such as exposure to tobacco smoke, chronic obstructive pulmonary diseases and eosinophilic granuloma have recently been found to be associated with an increase of pulmonary BLP-producing cells. Proinflammatory neuropeptides have a key role in the pathogenesis and maintenance of rheumatoid arthritis and sepsis. Together, these findings support the view that the GRPR should be considered a therapeutic target for a subset of inflammatory diseases.

Cytokine Profiles in Primary and Secondary Pulmonary Granulomas of Guinea Pigs with Tuberculosis

The cytokine mRNA profiles of primary (arising from inhaled bacilli) and secondary (arising from hematogenous reseeding of the lung) granulomas from the lung lobes of bacillus Calmette-Guérin (BCG)-vaccinated and unimmunized guinea pigs challenged with virulent Mycobacterium tuberculosis by the pulmonary route were assessed in situ using laser capture microdissection (LCM) at 6 weeks after infection. The challenge dose chosen was so low that some lung lobes did not receive an implant from the airway. In unimmunized guinea pigs, some lobes contained either large, necrotic primary lesions or small, non-necrotic secondary lesions, or both. The lobes of BCG-vaccinated animals contained only non-necrotic primary tubercles, and no secondary lesions were visible. Real-time PCR analysis of the acquired RNA clearly demonstrated that primary tubercles from BCG-vaccinated guinea pigs were overwhelmed with mRNA from the anti-inflammatory cytokine, transforming growth factor (TGF)-beta, with some IFN-gamma and IL-12p40 mRNA. In contrast, primary lesions from unimmunized animals were dominated by proinflammatory TNF-alpha mRNA. The cytokine mRNA profile of secondary lesions from unimmunized animals was strikingly similar to the profile of primary lesions from BCG-vaccinated guinea pigs (i.e., a predominance of TGF-beta mRNA with some IL-12p40 and IFN-gamma mRNA), indicating that the lung lobes from which these lesions were retrieved had been naturally "vaccinated" by the time the bloodborne bacilli returned to the lung at 3 to 4 weeks after infection. Furthermore, cytokine mRNA analysis of splenic granulomas from nonvaccinated and vaccinated animals showed close resemblance to primary granulomas recovered from the lungs of the same animal, that is, high levels of TNF-alpha mRNA in unimmunized animals, and mostly TGF-beta mRNA in BCG-vaccinated guinea pigs. Taken together, these data indicate that mycobacteria returning to the lungs of unimmunized guinea pigs 3 to 4 weeks after infection induce a local cytokine response that is fundamentally different from the response to inhaled bacilli and is reminiscent of the primary response in a vaccinated animal.

A systemic granulomatous response toSchistosoma mansonieggs alters responsiveness of bone marrow-derived macrophages to Toll-like receptor agonists

Macrophages play a pivotal role in innate and acquired immune responses to Schistosoma mansoni. Classical (M1) or alternative (M2) activation states of these cells further delineate their roles in tissue damage through innate immunity or fibrotic remodeling, respectively. In the present study, we addressed the following question: Does systemic Th2-type cytokine polarization evoked by S. mansoni affect macrophage differentiation and activation? To this end, we analyzed bone marrow-derived macrophages from mice with S. mansoni egg-induced pulmonary granulomas and unchallenged (or naïve) mice to determine their activation state and their response to specific TLR agonists, including S. mansoni egg antigens. Unlike naïve macrophages, macrophages from Th2-polarized mice constitutively expressed significantly higher "found in inflammatory zone-1" (FIZZ1) and ST2 (M2 markers) and significantly lower NO synthase 2, CCL3, MIP-2, TNF-alpha, and IL-12 (M1 markers). Also, compared with naïve macrophages, Th2-polarized macrophages exhibited enhanced responses to the presence of specific TLR agonists, which consistently induced significantly higher levels of gene and protein levels for M2 and M1 markers in these cells. Together, these data show that signals received by bone marrow precursors during S. mansoni egg-induced granuloma responses dynamically alter the development of macrophages and enhance the TLR responsiveness of these cells, which may ultimately have a significant effect on the pulmonary granulomatous response.

Characterization of the Deregulated Immune Activation Occurring at Late Stages of Mycobacterial Infection in TNF-Deficient Mice

In the absence of TNF, mice infected with Mycobacterium avium suffer a peculiar disintegration of the granulomas, with extensive apoptosis and necrosis of their cells, occurring during the course of the infection and leading to the death of the animals within a few days of its onset. The survival time depends on the virulence of the infecting strain as well as on the dose and route of infection. Intravenously infected mice developed the typical lesions in hepatic granulomas whereas aerosol-infected animals developed them in the lung granulomas. At the onset of the development of pulmonary granuloma disintegration, extensive expansion of T cells, with intense up-regulation of activation markers, massive exacerbation of their ability to secrete IFN-gamma, and increased cytotoxic activity of both CD4(+) and CD8(+) T cells were observed. Forced expression of Bcl2 did not prevent the early death of infected TNF-deficient mice leading merely to a modest increase in survival times. The expression of the FasL on T cells was not affected but there was an intense up-regulation of the TRAIL in T cells and, in particular, myeloid cells. We thus show that an exacerbated immune response occurs in TNF-deficient hosts during M. avium infections that leads to enhanced IFN-gamma production and late up-regulation of TRAIL which may contribute to granuloma disintegration.

High-resolution CT Findings in Pulmonary Hyalinizing Granuloma

A 47-year-old man with pulmonary hyalinizing granuloma is herein presented. The patient, whose chief complaint was a mild cough, was found by chest radiograph to have multiple bilateral nodules. Subsequent high-resolution computed tomography demonstrated multiple slightly irregular nodules, perinodular ground-glass opacity, peribronchovascular interstitial thickening, and cysts. A mild enlargement of systemic lymph nodes was also noted. Laboratory tests disclosed a slight elevation in the C-reactive protein, gamma-globulin, interleukin-6, and soluble interleukin-2 receptor levels. A histopathologic examination of the specimen yielded from a thoracoscopic lung biopsy resulted in a definite diagnosis of pulmonary hyalinizing granuloma.

Granulome pulmonaire hyalinisant révélé par une localisation à la base du crâne

Introduction Pulmonary hyalinizing granuloma is a rare fibrosing lesion of the lung, characterized by its histological appearance which includes central whorled deposits of lamellar collagen. The extrapulmonary diffusion of the disease is extremely rare, and in our knowledge any case of pituitary diffusion has ever been reported in the literature. Exegesis We reported an unpublished case of a 31-year-old woman presenting with amenorrhea, galactorrhea, diplopia, headache, polyuria and polydipsia. The diagnosis of pulmonary hyalinizing granuloma revealed by an intracranial localization was based on radiologic and pathologic findings. Clinical course was favourable with corticotherapy. Conclusion Our report is particular because cerebral localization was the initial manifestation of primary hyalinizing granuloma and because of the favourable outcome with corticotherapy.

Granulocyte–macrophage colony stimulating factor-mediated innate responses in tuberculosis

The mechanisms by which GM-CSF mediates bacterial clearance and inflammation during mycobacterial infection are poorly understood. The objective of this work was to determine how GM-CSF alters pulmonary mycobacterial infection in vivo. Differences in GM-CSF levels in the lungs of normal mice (GM(+/+)), transgenic GM-CSF-deficient (GM-CSF(-/-)), and transgenic mice with high GM-CSF expression only in lung epithelial cells (SP-C-GM-CSF(+/+)/GM(-/-)) did not affect pulmonary infection rates caused by either the attenuated Mycobacterium bovis BCG or the virulent Mycobacterium tuberculosis H37Rv. However, in contrast to findings with BCG, all GM-CSF(-/-) and SP-C-GM-CSF(+/+)/GM(-/-) mice succumbed prematurely to virulent H37Rv. Granuloma formation was impaired in both GM-CSF(-/-) and SP-C-GM-CSF(+/+)/GM(-/-) mice regardless of mycobacterial virulence. However, H37Rv-infected GM-CSF(-/-) mice suffered broncho-alveolar destruction, edema, and necrosis while only short-lived granulomas were observed in SP-C-GM-CSF(+/+)/GM(-/-) mice. Bone marrow-derived macrophages, but not dendritic cells of SP-C-GM-CSF(+/+)/GM(-/-) mice, were hypo-responsive to mycobacterial infection. Surfactant protein levels were differentially influenced by BCG and H37Rv. We conclude that GM-CSF has an essential protective role first in preserving alveolar structure and second in regulating macrophages and dendritic cells to facilitate containment of virulent mycobacteria in pulmonary granulomas. However, precise regulation of lung GM-CSF is vital to effective control of M. tuberculosis.