Etiologic aspect of sarcoidosis as an allergic endogenous infection caused by Propionibacterium acnes

Case Report: Tattoo sarcoidosis with epithelioid cell granuloma positive for Propionibacterium acnes

Introduction

Tattoo sarcoidosis is characterized by a granulomatous reaction localized to the tattoo site and typical systemic symptoms of sarcoidosis. Herein, we report the case of a patient diagnosed with tattoo sarcoidosis.

Case report

A 28-year-old man presented with subcutaneous nodules at two tattoo sites, bilateral hilar and mediastinal lymphadenopathy, multiple micronodules predominantly in the upper lobes of both lungs, elevated serum angiotensin-converting enzyme and soluble interleukin-2 receptor levels, hypercalcemia, and renal dysfunction. Skin biopsy of a subcutaneous nodule revealed epithelioid cell granulomas. Although periodic acid-Schiff, Grocott methenamine silver, and acid-fast staining showed negative results, antibody staining for Propionibacterium acnes within the epithelioid cell granuloma was positive. Remarkably, all lesions spontaneously resolved, and the systemic manifestations also improved without medical treatment.

Conclusion

The pathogenesis of tattoo sarcoidosis remains unknown, although an immune response to tattoo pigments has been suspected. However, there is a theory that P. acnes is the causative agent of sarcoidosis. In the present case, the detection of P. acnes within the epithelioid cell granuloma suggests that the bacterium may play a role in the etiology of tattoo sarcoidosis.

Cutibacterium acnes and its complex host interaction in prosthetic joint infection: Current insights and future directions

Cutibacterium acnes is a commensal Gram-positive anaerobic bacterium that can also act as an opportunistic pathogen in various diseases, particularly in prosthetic joint infections (PJI). Throughout this review, we delve into the current understanding of the intricate interactions between C. acnes and host cells and discuss bacterial persistence in the host. C. acnes colonization and subsequent PJI set-up represent complex processes involving bacterial adhesion, immune recognition, and host response mechanisms. We highlight existing knowledge and gaps in specific host-pathogen interactions and stress the importance of acquiring additional information to develop targeted strategies for preventing and treating C. acnes-related PIJ.

Dual Role of Cutibacterium acnes: Commensal Bacterium and Pathogen in Ocular Diseases

Microbiota present around the ocular surface, encompassing the eyelid skin, the conjunctival sac, and the meibomian glands, play a significant role in various inflammatory conditions associated with the ocular surface. Cutibacterium acnes (C. acnes), formerly, Propionibacterium acnes, is one of the most predominant commensal bacteria and its relative abundance declines with aging. However, it can act as both an infectious and an immunogenic pathogen. As an infectious pathogen, C. acnes has been reported to cause late onset endophthalmitis post-cataract surgery and infectious keratitis. On the other hand, it can trigger immune responses resulting in conditions such as phlyctenules in the cornea, chalazion in the meibomian glands, and granuloma formation in ocular sarcoidosis. This review explores the role of C. acnes in ocular inflammation, specifically highlighting its implications for diagnosis and management.

Cutaneous Sarcoidosis

Sarcoidosis is a multisystem disease that most commonly affects the lungs, lymphatic system, eyes, and skin but any organ may be involved. Cutaneous sarcoidosis most commonly presents as pink-red to red-brown papules and plaques that commonly affect the head and neck. With the skin being readily accessible for evaluation and biopsy, when sarcoidosis is suspected, dermatologic evaluation may be helpful for establishing a definitive diagnosis. Treatment strategy depends on the severity and distribution of skin lesions and should incorporate patient preference and treatment considerations for other organs that may be involved.

Sarcoidosis and Autoimmune Inflammatory Syndrome Induced by Adjuvants

Currently, sarcoidosis remains one of the diseases with unknown etiology, which significantly complicates its diagnosis and treatment. Various causes of sarcoidosis have been studied for many years. Both organic and inorganic trigger factors, provoking the development of granulomatous inflammation are considered. However, the most promising and evidence-based hypothesis is the development of sarcoidosis as an autoimmune disease, provoked by various adjuvants in genetic predisposed individuals. This concept fits into the structure of the autoimmune/inflammatory syndrome, induced by adjuvants (ASIA) that was proposed in 2011 by Professor Shoenfeld Y. In this paper, the authors reveal the presence of major and minor ASIA criteria for sarcoidosis, propose a new concept of the course of sarcoidosis within the framework of ASIA, and point out the difficulties in creating a model of the disease and the selection of therapy. It is obvious that the data obtained not only bring us closer to understanding the nature of sarcoidosis, but also potentiate new studies confirming this hypothesis by obtaining a model of the disease.

Potential Association of Cutibacterium acnes with Sarcoidosis as an Endogenous Hypersensitivity Infection

The immunohistochemical detection of Cutibacterium acnes in sarcoid granulomas suggests its potential role in granuloma formation. C. acnes is the sole microorganism ever isolated from sarcoid lesions. Histopathologic analysis of some sarcoid lymph nodes reveals latent infection and intracellular proliferation of cell-wall-deficient C. acnes followed by insoluble immune-complex formation. Activation of T helper type 1 (Th1) immune responses by C. acnes is generally higher in sarcoidosis patients than in healthy individuals. Pulmonary granulomatosis caused by an experimental adjuvant-induced allergic immune response to C. acnes is preventable by antimicrobials, suggesting that the allergic reaction targets C. acnes commensal in the lungs. C. acnes is the most common bacterium detected intracellularly in human peripheral lungs and mediastinal lymph nodes. Some sarcoidosis patients have increased amounts of C. acnes-derived circulating immune complexes, which suggests the proliferation of C. acnes in affected organs. In predisposed individuals with hypersensitive Th1 immune responses to C. acnes, granulomas may form to confine the intracellular proliferation of latent C. acnes triggered by certain host-related or drug-induced conditions. Current clinical trials in patients with cardiac sarcoidosis are evaluating combined treatment with steroids and antimicrobials during active disease with continued antimicrobial therapy while tapering off steroids after the disease subsides.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

Sarcoidosis is a systemic granulomatous inflammatory disease of unknown etiology. It affects the lungs in over 90% of patients yet extra-pulmonary and multi-organ involvement is common. Spontaneous remission of disease occurs commonly, nonetheless, over 50% of patients will require treatment and up to 30% of patients will develop a chronic progressive non-remitting disease with marked pulmonary fibrosis leading to significant morbidity and death. Guidelines outlining an immunosuppressive treatment approach to sarcoidosis were recently published, however, the strength of evidence behind many of the guideline recommended drugs is weak. None of the drugs currently used for the treatment of sarcoidosis have been rigorously studied and prescription of these drugs is often based on off-label” indications informed by experience with other diseases. Indeed, only two medications [prednisone and repository corticotropin (RCI) injection] currently used in the treatment of sarcoidosis are approved by the United States Food and Drug Administration. This situation results in significant reimbursement challenges especially for the more advanced (and often more effective) drugs that are favored for severe and refractory forms of disease causing an over-reliance on corticosteroids known to be associated with significant dose and duration dependent toxicities. This past decade has seen a renewed interest in developing new drugs and exploring novel therapeutic pathways for the treatment of sarcoidosis. Several of these trials are active randomized controlled trials (RCTs) designed to recruit relatively large numbers of patients with a goal to determine the safety, efficacy, and tolerability of these new molecules and therapeutic approaches. While it is an exciting time, it is also necessary to exercise caution. Resources including research dollars and most importantly, patient populations available for trials are limited and thus necessitate that several of the challenges facing drug trials and drug development in sarcoidosis are addressed. This will ensure that currently available resources are judiciously utilized. Our paper reviews the ongoing and anticipated drug trials in sarcoidosis and addresses the challenges facing these and future trials. We also review several recently completed trials and draw lessons that should be applied in future.

Is clindamycin a potential treatment for prostatitis?

Cutibacterium acnes has been associated with chronic prostatitis, which can potentially favor the appearance of tumors in the prostate. Prostatitis is difficult to treat, and the drug needs to be able to penetrate the prostate. The aim was to investigate the pharmacokinetics of clindamycin in the interstitial fluid of rat prostate using microdialysis. Microdialysis probes were recovered in vitro and in vivo. Clindamycin was administered at 80 mg/kg iv bolus for plasma and tissue pharmacokinetic experiments. A microdialysis probe was implanted in the prostate gland for collections over an 8-hour period. The pharmacokinetic parameters were determined by both compartmental and non-compartmental approaches. Penetration was determined as the ratio between the area under the curve and the time of the clindamycin measurement in the prostate. The recovery of the in vivo probes was 38.11 ± 1.14%. The plasma profile was modeled by a two-compartment pharmacokinetic model. Clindamycin presented a prostate/plasma ratio of 1.02, with free concentrations above the minimum inhibitory concentration for Cutibacterium acnes isolates. This was the first study that determined clindamycin free concentrations in the prostatic fluid of rats. These findings suggest that clindamycin may be an effective alternative for the treatment of prostatitis caused by Cutibacterium acnes.

Autoantibodies against cytoskeletons and lysosomal trafficking discriminate sarcoidosis from healthy controls, tuberculosis and lung cancers

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Hypergammaglobulinemia and the presence of autoantibodies in sarcoidosis suggest active humoral immunity to unknown antigen(s). We developed a complex cDNA library derived from tissues of sarcoidosis patients. Using a high throughput method, we constructed a microarray platform from this cDNA library containing large numbers of sarcoidosis clones. After selective biopanning, 1070 sarcoidosis-specifc clones were arrayed and immunoscreend with 152 sera from patients with sarcoidosis and other pulmonary diseases. To identify the sarcoidosis classifiers two statistical approaches were conducted: First, we identified significant biomarkers between sarcoidosis and healthy controls, and second identified markers comparing sarcoidosis to all other groups. At the threshold of an False Discovery Rate (FDR) < 0.01, we identified 14 clones in the first approach and 12 clones in the second approach discriminating sarcoidosis from other groups. We used the classifiers to build a naïve Bayes model on the training-set and validated it on an independent test-set. The first approach yielded an AUC of 0.947 using 14 significant clones with a sensitivity of 0.93 and specificity of 0.88, whereas the AUC of the second option was 0.92 with a sensitivity of 0.96 and specificity of 0.83. These results suggest robust classifier performance. Furthermore, we characterized the informative phage clones by sequencing and homology searches. Large numbers of classifier-clones were peptides involved in cellular trafficking and cytoskeletons. These results show that sarcoidosis is associated with a specific pattern of immunoreactivity that can discriminate it from other diseases.

A Solitary Necrotizing Sarcoid Granulomatosis-like Pulmonary Lesion Possibly Associated with Propionibacterium acnes and Mycobacterium avium

We report a case of a pulmonary necrotizing sarcoid granulomatosis (NSG)-like lesion possibly associated with coinfection of Mycobacterium avium and Propionibacterium acnes. A solitary nodule in the right middle lobe of the lung was notable for coagulative necrosis with aggregates of sarcoid-like epithelioid granulomas. Small arteries were damaged by granulomas. Both M. avium and P. acnes were detected in the lesion. Furthermore, more P. acnes genomes were detected in the granulomas than in the non-lesion lung. These findings blur the pathophysiologic boundaries among NSG, sarcoidosis, and mycobacteriosis, and suggest that NSG needs to be recognized as continuous spectra of sarcoidosis/mycobcteriosis.

Propionibacterium acnes-Derived Circulating Immune Complexes in Sarcoidosis Patients

Propionibacterium acnes is a potential etiologic agent of sarcoidosis and a dysregulated immune response to the commensal bacterium is suspected to cause granuloma formation. P. acnes-derived insoluble immune complexes were recently demonstrated in sinus macrophages of sarcoidosis lymph nodes, suggesting local proliferation of the bacterium in affected organs. In the present study, we developed a method for detecting P. acnes-derived immune complexes in human blood by measuring the concentration of P. acnes-specific lipoteichoic acid (PLTA) detectable after an antigen retrieval pretreatment of plasma samples. Before pretreatment, anti-PLTA antibody was detected and PLTA could not be detected, in all plasma samples from 51 sarcoidosis patients and 35 healthy volunteers. After pretreatment, however, a significant level of PLTA (>105 ng/mL) was detected in 33 (65%) sarcoidosis patients and 5 (14%) control subjects, with 86% specificity and 65% sensitivity for sarcoidosis. In both groups, plasma anti-PLTA antibody titers did not differ between samples with and without detection of PLTA. PLTA levels were abnormally increased (>202 ng/mL) in 21 (41%) sarcoidosis patients. These findings suggest that P. acnes-derived circulating immune complexes present in human blood are abnormally increased in many sarcoidosis patients, presumably due to local proliferation of the bacterium in the affected organs.

Immunohistochemical Detection of Propionibacterium acnes in Granulomas for Differentiating Sarcoidosis from Other Granulomatous Diseases Utilizing an Automated System with a Commercially Available PAB Antibody

Propionibacterium acnes is implicated in the pathogenesis of sarcoidosis. We investigated the usefulness of immunohistochemistry (IHC) with a commercially available P. acnes-specific monoclonal antibody (PAB antibody) for differentiating sarcoidosis from other granulomatous diseases. Formalin-fixed paraffin-embedded tissue samples from 94 sarcoidosis patients and 30 control patients with other granulomatous diseases were examined by the original manual IHC method. We also compared the detection frequency of P. acnes in sarcoid granulomas between manual and automated IHC methods. P. acnes was detected in sarcoid granulomas of samples obtained by transbronchial lung biopsy (64%), video-associated thoracic surgery (67%), endobronchial-ultrasound-guided transbronchial-needle aspiration (32%), lymph node biopsy (80%), and skin biopsy (80%) from sarcoidosis patients, but not in any non-sarcoid granulomas of the samples obtained from control patients. P. acnes outside granulomas, however, was frequently detected in both groups. The detection status of P. acnes in granulomas did not correlate with the clinical characteristics of sarcoidosis patients. The automated Leica system exhibited the best detection sensitivity (72%) and almost an identical localization for P. acnes in sarcoid granulomas compared with the manual method. IHC with a PAB antibody is useful for differentiating sarcoidosis from other granulomatous diseases by detecting P. acnes in granulomas. An automated method by the Leica system can be used in pathology laboratories for differential diagnosis of granulomas by IHC with the PAB antibody.

Immunohistochemical Detection of Potential Microbial Antigens in Granulomas in the Diagnosis of Sarcoidosis

Sarcoidosis may have more than a single causative agent, including infectious and non-infectious agents. Among the potential infectious causes of sarcoidosis, Mycobacterium tuberculosis and Propionibacterium acnes are the most likely microorganisms. Potential latent infection by both microorganisms complicates the findings of molecular and immunologic studies. Immune responses to potential infectious agents of sarcoidosis should be considered together with the microorganisms detected in sarcoid granulomas, because immunologic reactivities to infectious agents reflect current and past infection, including latent infection unrelated to the cause of the granuloma formation. Histopathologic data more readily support P. acnes as a cause of sarcoidosis compared with M. tuberculosis, suggesting that normally symbiotic P. acnes leads to granuloma formation in some predisposed individuals with Th1 hypersensitivity against intracellular proliferation of latent P. acnes, which may be triggered by certain host or drug-induced conditions. Detection of bacterial nucleic acids in granulomas does not necessarily indicate co-localization of the bacterial proteins in the granulomas. In the histopathologic diagnosis of sarcoidosis, M. tuberculosis-associated and P. acnes-associated sarcoidosis will possibly be differentiated in some patients by immunohistochemistry with appropriate antibodies that specifically react with mycobacterial and propionibacterial antigens, respectively, for each etiology-based diagnosis and potential antimicrobial intervention against sarcoidosis.

Propionibacterium acnes-associated Sarcoidosis Possibly Initially Triggered by Interferon-alpha Therapy

A 46-year-old woman with uveitis was referred to our respiratory diseases department in July 2018. Her medical history included transient bilateral hilar mediastinal lymphadenopathy (BHL) and multiple pulmonary nodules in May 2013 during pegylated interferon-alpha and ribavirin treatment for chronic hepatitis C infection. Five years post-treatment, chest X-ray revealed BHL and nodular recurrence. A biopsy of the subcutaneous buttock nodules revealed scattered non-caseating epithelioid granulomas with positive PAB immunohistochemical staining. This seem to be the first report of Propionibacterium acnes-associated sarcoidosis possibly initially triggered by interferon-alpha therapy. Understanding the mechanisms underlying interferon-triggered P. acnes-associated sarcoidosis may clarify the sarcoidosis immunopathogenesis.

A novel mutation in early-onset sarcoidosis/Blau syndrome: an association with Propionibacterium acnes

BACKGROUND

Early-onset sarcoidosis (EOS) and Blau syndrome (BS) are systemic inflammatory granulomatous diseases without visible pulmonary involvement, and are distinguishable from their sporadic and familial forms. The diseases are characterized by a triad of skin rashes, symmetrical polyarthritis, and recurrent uveitis. The most common morbidity is ocular involvement, which is usually refractory to conventional treatment. A gain-of-function mutation in the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene has been demonstrated in this disease; however, little is known about the relationship between the activation of NOD2 and the pathophysiology of EOS/BS. Here we describe EOS/BS with a novel mutation in the NOD2 gene, as well as detection of Propionibacterium acnes (P. acnes) in the granulomatous inflammation.

CASE PRESENTATION

An 8-year-old Japanese girl presented with refractory bilateral granulomatous panuveitis. Although no joint involvement was evident, she exhibited skin lesions on her legs; a skin biopsy revealed granulomatous dermatitis, and P. acnes was detected within the sarcoid granulomas by immunohistochemistry with P. acnes-specific monoclonal (PAB) antibody. Genetic analyses revealed that the patient had a NOD2 heterozygous D512V mutation that was novel and not present in either of her parents. The mutant NOD2 showed a similar activation pattern to EOS/BS, thus confirming her diagnosis. After starting oral prednisolone treatment, she experienced an anterior vitreous opacity relapse despite gradual prednisolone tapering; oral methotrexate was subsequently administered, and the patient responded positively.

CONCLUSIONS

We presented a case of EOS/BS with a novel D512V mutation in the NOD2 gene. In refractory granulomatous panuveitis cases without any joint involvement, EOS/BS should be considered as a differential diagnosis; genetic analyses would lead to a definite diagnosis. Moreover, this is the first report of P. acnes demonstrated in granulomas of EOS/BS. Since intracellular P. acnes activates nuclear factor-kappa B in a NOD2-dependent manner, we hypothesized that the mechanism of granuloma formation in EOS/BS may be the result of NOD2 activity in the presence of the ligand muramyl dipeptide, which is a component of P. acnes. These results indicate that recognition of P. acnes through mutant NOD2 is the etiology in this patient with EOS/BS.

Novel three-dimensional biochip pulmonary sarcoidosis model

Sarcoidosis is a multi-system disorder of granulomatous inflammation which most commonly affects the lungs. Its etiology and pathogenesis are not well defined in part due to the lack of reliable modeling. Here, we present the development of an in vitro three-dimensional lung-on-chip biochip designed to mimic granuloma formation. A lung on chip fluidic macrodevice was developed and added to our previously developed a lung-on-membrane model (LOMM). Granulomas were cultured from blood samples of patients with sarcoidosis and then inserted in the air-lung-interface of the microchip to create a three-dimensional biochip pulmonary sarcoidosis model (3D BSGM). Cytokines were measured after 48 hours. ELISA testing was performed to measure cytokine response difference between LOMM with 3D BSGM. There were statistically significant differences in IL-1ß (P = 0.001953), IL-6 (P = 0.001953), GM-CSF (P = 0.001953), and INF-γ expressions (P = 0.09375) between two groups. The current model represents the first 3D biochip sarcoidosis model created by adding a microfluidics system to a dual-chambered lung on membrane model and introducing developed sarcoid-granuloma to its air-lung-interface.

Cutibacterium acnes is an intracellular and intra-articular commensal of the human shoulder joint

BACKGROUND

Cutibacterium acnes (C acnes) is a mysterious member of the shoulder microbiome and is associated with chronic postoperative complications and low-grade infections. Nevertheless, it is unclear whether it represents a contaminant or whether it accounts for true infections. Because it can persist intracellularly in macrophages at several body sites, it might in fact be an intra-articular commensal of the shoulder joint.

METHODS

In 23 consecutive, otherwise healthy patients (17 male, 6 female; 58 years) who had no previous injections, multiple specimens were taken from the intra-articular tissue during first-time arthroscopic and open shoulder surgery. The samples were investigated by cultivation, genetic phylotyping, and immunohistochemistry using C acnes-specific antibodies and confocal laser scanning microscopy.

RESULTS

In 10 patients (43.5%), cultures were C acnes-positive. Phylotype IA1 dominated the subcutaneous samples (71%), whereas type II dominated the deep tissue samples (57%). Sixteen of 23 patients (69.6%) were C acnes-positive by immunohistochemistry; in total, 25 of 40 samples were positive (62.5%). Overall, 56.3% of glenohumeral immunohistochemical samples, 62.5% of subacromial samples, and 75% of acromioclavicular (AC) joint samples were positive. In 62.5% of the tested patients, C acnes was detected immunohistochemically to reside intracellularly within stromal cells and macrophages.

DISCUSSION

These data indicate that C acnes is a commensal of the human shoulder joint, where it persists within macrophages and stromal cells. Compared with culture-based methods, immunohistochemical staining can increase C acnes detection. Phylotype II seems to be most prevalent in the deep shoulder tissue. The high detection rate of C acnes in osteoarthritic AC joints might link its intra-articular presence to the initiation of osteoarthritis.

Cutaneous Sarcoidosis

Sarcoidosis is a chronic, multisystem, inflammatory disorder of unknown etiology that is characterized by noncaseating granulomas that impair normal organ functioning. Sarcoidosis predominantly affects the lungs, but the skin is often cited as the second most frequently involved organ. Cutaneous manifestations of sarcoidosis are highly variable and ongoing research seeks to better understand the relationship between clinical morphology and disease prognosis. Skin findings in patients with sarcoidosis can be "specific," in which sarcoidal granulomas infiltrate the skin, or they can represent a "nonspecific" reactive inflammatory process, as is seen in calcinosis cutis and erythema nodosum. Cutaneous sarcoidosis can be the initial presenting sign or develop later in the course of the disease. In some patients, the skin will be the most involved and impactful organ system and will drive therapy. In other cases, the skin will be an incidental or minor finding, but may be easily accessible for biopsy to confirm the diagnosis. There are many potential therapies for sarcoidosis, though no one therapy is universally effective.

Misidentification of Cutibacterium namnetense as Cutibacterium acnes among clinical isolates by MALDI-TOF VitekMS: usefulness of gyrB sequencing and new player in bone infections

The taxonomy modification of Propionibacterium sp. with the description of new species, especially Cutibacterium namnetense, raises the question of species distribution in routine clinical samples. We performed a retrospective study during 3 years before the implementation of MALDI-TOF. Two hundred sixty-nine isolates were included in the study. MALDI-TOF identification, 16S rRNA, and new developed gyrB partial sequencings were performed. The most representative species was C. acnes in 88% of the cases, regardless of the origin of the clinical sample. Eventually, we identified three C. namnetense strains, representing a 1.1% prevalence over the period of time, including two bone infections. MALDI-TOF databases should be regularly updated to incorporate new species. gyrB sequencing constitutes a both easy and relevant method to identify Cutibacterium sp. especially C. namnetense, a new player in bone infections.

Catalase expression of Propionibacterium acnes may contribute to intracellular persistence of the bacterium in sinus macrophages of lymph nodes affected by sarcoidosis

Bacterial catalase is important for intracellular survival of the bacteria. This protein of Propionibacterium acnes, one of possible causes of sarcoidosis, induces hypersensitive Th1 immune responses in sarcoidosis patients. We examined catalase expression in cultured P. acnes isolated from 19 sarcoid and 18 control lymph nodes and immunohistochemical localization of the protein in lymph nodes from 43 sarcoidosis and 102 control patients using a novel P. acnes-specific antibody (PAC) that reacts with the catalase protein, together with the previously reported P. acnes-specific PAB and TIG antibodies. High catalase expression of P. acnes cells was found during stationary phase in more isolates from sarcoid than from non-sarcoid lymph nodes and was associated with bacterial survival under H₂O₂-induced oxidative stress. In many sarcoid and some control lymph nodes, catalase expression was detected at the outer margins of PAB-reactive Hamazaki-Wesenberg (HW) bodies in sinus macrophages, the same location as catalase expression on the surface of cultured P. acnes and the same distribution as bacterial cell membrane-bound lipoteichoic acid in HW bodies. Some or no catalase expression was detected in sarcoid granulomas with PAB reactivity or in clustered paracortical macrophages packed with many PAB-reactive small-round bodies. HW bodies expressing catalase may be persistent P. acnes in sinus macrophages whereas PAB-reactive small-round bodies with undetectable catalase may be activated P. acnes proliferating in paracortical macrophages. Intracellular proliferation of P. acnes in paracortical macrophages may lead to granuloma formation by this commensal bacterium in sarcoidosis patients with Th1 hypersensitivity to certain P. acnes antigens, including catalase.

Propionibacterium acnes-associated chronic hypertrophic pachymeningitis followed by refractory otitis media: a case report

BACKGROUND

Hypertrophic pachymeningitis (HP) is a rare disorder that involves localized or diffuse thickening of the dura mater. HP is associated with various inflammatory, infectious, and malignant diseases, such as rheumatic arthritis, sarcoidosis, anti-neutrophil cytoplasmic antibody-associated vasculitis, IgG4-related disorders, syphilis, tuberculosis, bacterial and fungal infections, cancer, and idiopathic diseases, when evaluation fails to reveal a cause. Among them, chronic infection with Propionibacterium acnes is a rare etiology of HP, and its pathology remains unclear.

CASE PRESENTATION

An 80-year-old man having refractory otitis media with effusion of the right ear presented with progressive right-sided headache and nausea. Post-contrast brain magnetic resonance imaging revealed right mastoiditis and remarkable thickening of the dura mater and enhancement of pia mater extending from the right middle cranial fossa to the temporal lobe. HP secondary to middle ear infection was suspected, and a biopsy of the right mastoid was performed. An anaerobic culture of the biopsied right mastoid showed the growth of P. acnes, and histopathological examination using P. acnes-specific monoclonal antibody (PAB antibody) revealed the infiltration of inflammatory cells with P. acnes. Moreover, using PAB antibody, P. acnes was detected in the biopsy specimen of the thickening dura mater. No granulomas were identified in either specimen. HP was resolved with long-term administration of antibiotics and steroids.

CONCLUSION

This is the first documentation of pathologically demonstrated chronic HP associated with P. acnes infection followed by refractory otitis media. This report showed that chronic latent P. acnes infection induces chronic inflammation.

Sarcoidosis as an Autoimmune Disease

Despite the large number of performed studies, the etiology and pathogenesis of sarcoidosis still remain unknown. Most researchers allude to the possible autoimmune or immune-mediated genesis of the disease. This review attempts an integral analysis of currently available information suggesting an autoimmune genesis of sarcoidosis and is divided into four categories: the evaluation of clinical signs described both in patients with sarcoidosis and “classic” autoimmune diseases, the role of triggering factors in the development of sarcoidosis, the presence of immunogenic susceptibility in the development of the disease, and the analysis of cellular and humoral immune responses in sarcoidosis. Studying the etiology and pathogenesis of sarcoidosis will improve diagnostic procedures as well as the prognosis and patients' quality of life.

Host-microbe interactions in the pathogenesis and clinical course of sarcoidosis

Sarcoidosis is a rare inflammatory disease characterized by the development of granulomas in various organs, especially in the lungs and lymph nodes. Clinics of the disease largely depends on the organ involved and may range from mild symptoms to life threatening manifestations. Over the last two decades, significant advances in the diagnosis, clinical assessment and treatment of sarcoidosis have been achieved, however, the precise etiology of this disease remains unknown. Current evidence suggests that, in genetically predisposed individuals, an excessive immune response to unknown antigen/s is crucial for the development of sarcoidosis. Epidemiological and microbiological studies suggest that, at least in a fraction of patients, microbes or their products may trigger the immune response leading to sarcoid granuloma formation. In this article, we discuss the scientific evidence on the interaction of microbes with immune cells that may be implicated in the immunopathogenesis of sarcoidosis, and highlight recent studies exploring potential implications of human microbiota in the pathogenesis and the clinical course of sarcoidosis.

Development of Propionibacterium acnes-associated Sarcoidosis During Etanercept Therapy

Although numerous recent studies have reported the development of sarcoidosis in patients treated with tumor necrosis factor alpha (TNF-α) inhibitors, it is unclear whether the pathogenesis of drug-induced sarcoidosis is identical to that of spontaneous sarcoidosis. We herein present the case of a patient who developed sarcoidosis 6 months after the introduction of etanercept as treatment for rheumatoid arthritis. Typical clinical symptoms with noncaseating epithelioid granulomas detected in a mediastinal lymph node specimen were consistent with the diagnosis of sarcoidosis. Immunohistochemistry revealed Propionibacterium acnes in the noncaseating granulomas. The present findings suggest that Propionibacterium acnes is a cause of sarcoidosis, even when the disease is induced by TNF-α inhibitors.

The combination of EBUS-TBNA and the PAB antibody led to a successful treatment for lung cancer in a patient with asymptomatic sarcoidosis mimicking nodal metastasis

Correct staging of lung cancer is important for the selection of the best therapy, but discriminating between lymphadenopathy from lung cancer and from sarcoidosis by imaging examinations is difficult. Additionally, distinguishing lymphadenopathy of sarcoidosis from sarcoid reactions which are sometimes caused by lung cancer is difficult on imaging and pathological findings. A 73-year-old woman was diagnosed as lung cancer clinical T1bN3M0 stage ШB based on false-positive ¹⁸F-fluoro-2-deoxyglucose positron emission tomography uptake. Because the effects of chemotherapy were different between the lymphadenopathy and the primary lesion, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) was performed and revealed sarcoidosis as the cause of the lymphadenopathy with using a specific monoclonal antibody against Propionibacterium acnes (PAB antibody). Accordingly, the stage was changed to clinical T1bN0M0 stage ІA, for which radical operation was performed. EBUS-TBNA should be performed aggressively when the effect of chemotherapy is different between lymphadenopathies and other lesions, and the PAB antibody can help to discriminate between sarcoidosis and sarcoid reactions caused by lung cancer. The combination of EBUS-TBNA and the PAB antibody is expected to be valuable in the definitive diagnosis of a lymphadenopathy for the staging of lung cancer.

Sarcoidosis of the fallopian tube: A rare case study with confirmed Propionibacterium acnes infection

Sarcoidosis is a systemic granulomatous disease that is most commonly manifested in the pulmonary system. Though the entire etiology of sarcoidosis remains unknown, it has been reported that Propionibacterium acnes (P. acnes) has been isolated from sarcoid lesions. Herein, we report a case of salpingitis arising from sarcoidosis. A female patient aged 37 years, gravida 2 para 0, who had been diagnosed with sarcoidosis at the age of 36 years, underwent laparoscopic right salpingectomy due to obvious right hydrosalpinx with recurrent refractory right lower abdominal pain. The pathological diagnosis was granulomatous salpingitis of the right fallopian tube suspecting sarcoidosis. Immunocytochemistry using a specific monoclonal antibody against P. acnes lipoteichoic acid (PAB antibody) revealed PAB-positive reaction in sarcoid granuloma. This is the first case of sarcoidosis that the presence of P. acnes was shown in sarcoid lesions in the fallopian tube.

Cutaneous Granulomatosis: a Comprehensive Review

Cutaneous granulomatosis is a heterogeneous group of diseases, characterized by a skin inflammatory reaction triggered by a wide variety of stimuli, including infections, foreign bodies, malignancy, metabolites, and chemicals. From a pathogenic point of view, they are divided into non-infectious and infectious granulomas. Pathophysiological mechanisms are still poorly understood. Non-infectious granulomatous skin diseases include granuloma annulare, necrobiosis lipoidica, rheumatic nodules, foreign body granulomas, cutaneous sarcoidosis, and interstitial granulomatous dermatitis. Necrobiosis lipoidica is more frequent in diabetic patients. Infectious granulomas of the skin are caused by mycobacteria, in particular Mycobacterium tuberculosis or atypical mycobacteria; parasites, such as Leishmania; or fungi. Pathogenic mechanisms of M. tuberculosis-related granuloma are discussed. From a clinical point of view, it is useful to divide cutaneous granulomatosis into localized and more disseminated forms, although this distinction can be sometimes artificial. Three types of localized granulomatous lesions can be distinguished: palisaded granulomas (granuloma annulare, necrobiosis lipoidica, and rheumatoid nodules), foreign body granulomas, and infectious granulomas, which are generally associated with localized infections. Disseminated cutaneous granulomas can be divided into infectious, in particular tuberculosis, and non-infectious forms, among which sarcoidosis and interstitial granulomatous dermatitis. From a histological point of view, the common denominator is the presence of a granulomatous inflammatory infiltrate in the dermis and/or hypodermis; this infiltrate is mainly composed of macrophages grouped into nodules having a nodular, palisaded or interstitial architecture. Finally, we propose which diagnostic procedure should be performed when facing a patient with a suspected cutaneous granulomatosis.

Propionibacterium acnes-derived insoluble immune complexes in sinus macrophages of lymph nodes affected by sarcoidosis

Background

Propionibacterium acnes is thought to be a causative agent of sarcoidosis. Patients with sarcoidosis have circulating immune complexes. We attempted to detect P. acnes-derived immune complexes in sarcoid lesions.

Methods

We evaluated formalin-fixed and paraffin-embedded lymph node samples from 38 sarcoidosis patients and 90 non-sarcoidosis patients (27 patients with necrotizing lymphadenitis, 28 patients with reactive lymphadenitis, 16 patients with colon cancer, 19 patients with gastric cancer) by immunohistochemistry using anti-human immunoglobulins (IgG, IgA, and IgM) and complement (C1q and C3c) antibodies, and a P. acnes-specific monoclonal antibody (PAB antibody) that reacts with the membrane-bound lipoteichoic acid of P. acnes.

Results

Small round bodies (SRBs) bound to IgA, IgM, or IgG were detected in sinus macrophages, in 32 (84%), 32 (84%), or 11 (29%) sarcoid samples, respectively, and in 19 (21%), 26 (29%), or no (0%) control samples, respectively. Some of these insoluble immune complexes (IICs) also bound to C1q and C3c. We developed a microwave treatment followed by brief trypsin digestion (MT treatment) to detect PAB-reactive SRBs bound to immunoglobulins (IIC-forming P. acnes). MT treatment revealed abundant IIC-forming P. acnes in most (89%) of the sarcoid samples and sparse distribution in some (20%) of the control samples with lymphadenitis, but no IIC-forming P. acnes was detected in control samples without inflammation. IIC-forming P. acnes were mostly bound to both IgA and IgM. The PAB-reactive antigen and immunoglobulins were both located at the peripheral rim of the IIC-forming P. acnes. Conventional electron microscopy identified many SRBs (0.5–2.0 μm diameter) in sinus macrophages of sarcoid lymph nodes with many IIC-forming P. acnes, some of which were in phagolysosomes with a degraded and lamellar appearance.

Conclusions

P. acnes-derived IICs in sinus macrophages were frequent and abundant in sarcoid lymph nodes, suggesting a potential etiologic link between sarcoidosis and this commensal bacterium.

Immunohistochemical Detection of Propionibacterium acnes in the Retinal Granulomas in Patients with Ocular Sarcoidosis

The etiology of sarcoidosis is still obscure; however, Mycobacteria and Propionibacterium acnes are considered the most implicated etiological agent for sarcoidosis. To investigate whether P. acnes is an etiological agent for sarcoid uveitis, we analyzed the frequency of P. acnes detected within the biopsied retinas from patients with ocular sarcoidosis by immunohistochemistry with a P. acnes-specific monoclonal antibody (PAB antibody). Eleven patients (12 eyes) with sarcoid uveitis were enrolled in this study. Eight patients with rhegmatogenous retinal detachment, two patients with non-sarcoid uveitis, and two patients with vitreoretinal lymphoma were enrolled as controls. In the sarcoidosis group, granulomas were mainly observed in the inner retinal layer filled with CD4+ cells and CD68+ cells, indicating the Th1 immune response. P. acnes, identified as round bodies that reacted with the PAB antibody, were present in 10/12 samples (83%) from 9/11 patients (82%) with sarcoidosis. These round bodies were scattered within the retinal granulomas mainly in the inner retinal layer. In the control group, no round bodies were detected. Our results suggested that P. acnes could be associated with sarcoid uveitis. We hypothesize that sarcoid granulomas may be formed by a Th1 immune response to P. acnes hematogenously transmitted to the retina.

Immunohistochemical identification of Propionibacterium acnes in granuloma and inflammatory cells of myocardial tissues obtained from cardiac sarcoidosis patients

Background

Although rare, cardiac sarcoidosis (CS) is potentially fatal. Early diagnosis and intervention are essential, but histopathologic diagnosis is limited. We aimed to detect Propionibacterium acnes, a commonly implicated etiologic agent of sarcoidosis, in myocardial tissues obtained from CS patients.

Methods and results

We examined formalin-fixed paraffin-embedded myocardial tissues obtained by surgery or autopsy and endomyocardial biopsy from patients with CS (n = 26; CS-group), myocarditis (n = 15; M-group), or other cardiomyopathies (n = 39; CM-group) using immunohistochemistry (IHC) with a P. acnes-specific monoclonal antibody. We found granulomas in 16 (62%) CS-group samples. Massive (≥14 inflammatory cells) and minimal (<14 inflammatory cells) inflammatory foci, respectively, were detected in 16 (62%) and 11 (42%) of the CS-group samples, 10 (67%) and 10 (67%) of the M-group samples, and 1 (3%) and 18 (46%) of the CM-group samples. P. acnes-positive reactivity in granulomas, massive inflammatory foci, and minimal inflammatory foci were detected in 10 (63%), 10 (63%), and 8 (73%) of the CS-group samples, respectively, and in none of the M-group and CM-group samples.

Conclusions

Frequent identification of P. acnes in sarcoid granulomas of originally aseptic myocardial tissues suggests that this indigenous bacterium causes granuloma in many CS patients. IHC detection of P. acnes in massive or minimal inflammatory foci of myocardial biopsy samples without granulomas may be useful for differentiating sarcoidosis from myocarditis or other cardiomyopathies.

A case of bilateral hilar and mediastinal lymphadenopathy developing during treatment for Mycobacterium avium complex

We report a rare case of an immunocompetent patient with Mycobacterium avium complex (MAC) disease in which bilateral hilar lymphadenopathy developed during anti-MAC treatment. This case indicates that Propionibacterium acnes would be present and might be a cause of sarcoidosis even in patients with MAC.

Induction of Pulmonary Granuloma Formation by Propionibacterium acnes Is Regulated by MyD88 and Nox2

Sarcoidosis is characterized by noncaseating granulomas with an unknown cause that present primarily in the lung. Propionibacterium acnes, an immunogenic commensal skin bacterium involved in acne vulgaris, has been implicated as a possible causative agent of sarcoidosis. Here, we demonstrate that a viable strain of P. acnes isolated from a patient with sarcoidosis and instilled intratracheally into wild-type mice can generate pulmonary granulomas similar to those observed in patients with sarcoidosis. The formation of these granulomas is dependent on the administration of viable P. acnes. We also found that mice deficient in the innate immunity adapter protein MyD88 had a greater number and a larger area of granuloma lesions compared with wild-type mice administered P. acnes. Early after P. acnes administration, wild-type mice produced proinflammatory mediators and recruited neutrophils into the lung, a response that is dependent on MyD88. In addition, there was an increase in granuloma number and size after instillation with P. acnes in mice deficient in CybB, a critical component of nicotinamide adenine dinucleotide phosphate oxidase required for the production of reactive oxygen species in the phagosome. Myd88^-/- or Cybb^-/- mice both had increased persistence of P. acnes in the lung, together with enhanced granuloma formation. In conclusion, we have generated a mouse model of early granuloma formation induced by a clinically relevant strain of P. acnes isolated from a patient with sarcoidosis, and, using this model, we have shown that a deficiency in MyD88 or CybB is associated with impaired bacterial clearance and increased granuloma formation in the lung.

SAPHO, autophagy, IL-1, FoxO1, and Propionibacterium (Cutibacterium) acnes

Overt infection by Propionibacterium acnes is lacking in many SAPHO syndromes, and antibiotics have only a transient and incomplete effect, either in SAPHO syndrome or acne. As several auto-inflammatory bone disorders sharing overproduction of IL-1β can mimic SAPHO, this syndrome could partly depend on genetically encoded overproduction of IL-1β. However, cyclic intracellular infections, mostly by P. acnes, can contribute to the enhanced IL-1β release by some skin cells, and probably by bone cells. P. acnes is indeed a powerful trigger of NLRP3-inflammasome activation and IL-1β, leading to osteitis and enhanced mesenchymal cells differentiation in osteoblasts. Recent advances in the understanding of acne suggest that first steps of this disorder are not driven by P. acnes, but by a relative deficiency of FoxO1 within the nucleus of sebaceous cells. A similar defect of FoXO1 in bone cells should also be sought in SAPHO, since repression of FoxO1 gene is found in lesional psoriasis skin, and is associated with an increased number of osteoblasts and high bone mass in mice. FoxO1 selectively promotes IL-1β production, so that its downregulation could help some P. acnes t escape innate immunity and persist in a latent state in bone cells, including mesenchymal stem cells. However, P. acnes itself possibly contributes to FoxO1 downregulation, like H. pylori infection which induces nuclear inactivation of FoxO1 in human gastric cells to slow down autophagic clearance. As bisphosphonates, which often improve SAPHO syndromes, enhance autophagy, it may be worth testing whether their combination with antibiotics is synergistic in SAPHO syndromes.

Propionibacterium acnes biofilm is present in intervertebral discs of patients undergoing microdiscectomy

Background

In previous studies, Propionibacterium acnes was cultured from intervertebral disc tissue of ~25% of patients undergoing microdiscectomy, suggesting a possible link between chronic bacterial infection and disc degeneration. However, given the prominence of P. acnes as a skin commensal, such analyses often struggled to exclude the alternate possibility that these organisms represent perioperative microbiologic contamination. This investigation seeks to validate P. acnes prevalence in resected disc cultures, while providing microscopic evidence of P. acnes biofilm in the intervertebral discs.

Methods

Specimens from 368 patients undergoing microdiscectomy for disc herniation were divided into several fragments, one being homogenized, subjected to quantitative anaerobic culture, and assessed for bacterial growth, and a second fragment frozen for additional analyses. Colonies were identified by MALDI-TOF mass spectrometry and P. acnes phylotyping was conducted by multiplex PCR. For a sub-set of specimens, bacteria localization within the disc was assessed by microscopy using confocal laser scanning and FISH.

Results

Bacteria were cultured from 162 discs (44%), including 119 cases (32.3%) with P. acnes. In 89 cases, P. acnes was cultured exclusively; in 30 cases, it was isolated in combination with other bacteria (primarily coagulase-negative Staphylococcus spp.) Among positive specimens, the median P. acnes bacterial burden was 350 CFU/g (12 - ~20,000 CFU/g). Thirty-eight P. acnes isolates were subjected to molecular sub-typing, identifying 4 of 6 defined phylogroups: IA₁, IB, IC, and II. Eight culture-positive specimens were evaluated by fluorescence microscopy and revealed P. acnes in situ. Notably, these bacteria demonstrated a biofilm distribution within the disc matrix. P. acnes bacteria were more prevalent in males than females (39% vs. 23%, p = 0.0013).

Conclusions

This study confirms that P. acnes is prevalent in herniated disc tissue. Moreover, it provides the first visual evidence of P. acnes biofilms within such specimens, consistent with infection rather than microbiologic contamination.

What is new in the histogenesis of granulomatous skin diseases?

A granuloma is a form of inflammation, which predominantly consists of macrophages. It typically develops when the immune system attempts to enclose substances that are usually insoluble and cannot be eliminated to prevent the spread of these substances to the other body compartments. According to the source of the substances, granulomatous diseases can be divided into two groups: infectious and non-infectious. The mechanisms of infectious granuloma formation have been widely investigated because of its easy reproducibility in experimental models, both in vivo and in vitro. On the contrary, mechanisms of non-infectious granuloma formation have not been well investigated because of the difficulty to reproduce this formation in experimental models. In this article, we review our recent understanding of the histogenesis and pathogenesis of granuloma formation, confirmed from studies of infectious granulomas, and we present potential hypotheses of the histogenesis and pathogenesis of non-infectious granulomas based on clinical investigations.

High throughput 16SrRNA gene sequencing reveals the correlation between Propionibacterium acnes and sarcoidosis

Objective

This study aims to use high throughput 16SrRNA gene sequencing to examine the bacterial profile of lymph node biopsy samples of patients with sarcoidosis and to further verify the association between Propionibacterium acnes (P. acnes) and sarcoidosis.

Methods

A total of 36 mediastinal lymph node biopsy specimens were collected from 17 cases of sarcoidosis, 8 tuberculosis (TB group), and 11 non-infectious lung diseases (control group). The V4 region of the bacterial 16SrRNA gene in the specimens was amplified and sequenced using the high throughput sequencing platform MiSeq, and bacterial profile was established. The data analysis software QIIME and Metastats were used to compare bacterial relative abundance in the three patient groups.

Results

Overall, 545 genera were identified; 38 showed significantly lower and 29 had significantly higher relative abundance in the sarcoidosis group than in the TB and control groups (P < 0.01). P. acnes 16SrRNA was exclusively found in all the 17 samples of the sarcoidosis group, whereas was not detected in the TB and control groups. The relative abundance of P. acnes in the sarcoidosis group (0.16% ± 0. 11%) was significantly higher than that in the TB (Metastats analysis: P = 0.0010, q = 0.0044) and control groups (Metastats analysis: P = 0.0010, q = 0.0038). The relative abundance of P. granulosum was only 0.0022% ± 0. 0044% in the sarcoidosis group. P. granulosum 16SrRNA was not detected in the other two groups.

Conclusion

High throughput 16SrRNA gene sequencing appears to be a useful tool to investigate the bacterial profile of sarcoidosis specimens. The results suggest that P. acnes may be involved in sarcoidosis development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0515-z) contains supplementary material, which is available to authorized users.

The role of pattern recognition receptors in lung sarcoidosis

Sarcoidosis is a granulomatous disorder of unknown etiology. Infection, genetic factors, autoimmunity and an aberrant innate immune system have been explored as potential causes of sarcoidosis. The etiology of sarcoidosis remains unknown, and it is thought that it might be caused by an infectious agent in a genetically predisposed, susceptible host. Inflammation results from recognition of evolutionarily conserved structures of pathogens (Pathogen-associated molecular patterns, PAMPs) and/or from reaction to tissue damage associated patterns (DAMPs) through recognition by a limited number of germ line-encoded pattern recognition receptors (PRRs). Due to the similar clinical and histopathological picture of sarcoidosis and tuberculosis, Mycobacterium tuberculosis antigens such early secreted antigen (ESAT-6), heat shock proteins (Mtb-HSP), catalase-peroxidase (katG) enzyme and superoxide dismutase A peptide (sodA) have been often considered as factors in the etiopathogenesis of sarcoidosis. Potential non-TB-associated PAMPs include lipopolysaccharide (LPS) from the outer membrane of Gram-negative bacteria, peptidoglycan, lipoteichoic acid, bacterial DNA, viral DNA/RNA, chitin, flagellin, leucine-rich repeats (LRR), mannans in the yeast cell wall, and microbial HSPs. Furthermore, exogenous non-organic antigens such as metals, silica, pigments with/without aluminum in tattoos, pesticides, and pollen have been evoked as potential causes of sarcoidosis. Exposure of the airways to diverse infectious and non-infectious agents may be important in the pathogenesis of sarcoidosis. The current review provides and update on the role of PPRs and DAMPs in the pathogenesis of sarcoidsis.

β-glucan in the lymph nodes in sarcoidosis and in Kveim-Siltzbach test reagent

Background: Previous studies have demonstrated a relationship between biomass of fungi exposure in the home and the risk of sarcoidosis. β-glucan was present in the bronchial alveolar lavage fluid (BALF) of patients with sarcoidosis. The Kveim-Siltzbach test reagent (KSTR) induces a sarcoidosis specific, granulomatous, cutaneous response and was used to establish the diagnosis. To date, the granuloma-inducing component of KSTR is still unknown. The present study was undertaken to investigate the presence of β-glucan in the lymph nodes of patients with sarcoidosis and to determine the relationship between the amounts of this agent with disease severity and to investigate the presence of β-glucan in KSTR. Materials and methods: Lymph node aspirations were collected by transbronchial needle aspiration (TBNA) in region R4 or 7 from patients with newly diagnosed sarcoidosis. The samples were treated to isolate β-glucan and analyzed using a Limulus-based assay. Cultures of Propionibacterium ac. and Mycobacterium gordonae as well as samples of Kveim-Siltzbach test reagent were analyzed to determine β-glucan content. Results: A significant relationship was observed between the amount of the β-glucan in the lymph nodes and the extent of granuloma formation in the lung parenchyma, and the size of the lymph nodes in the mediastinum (r=0.787, p=0.0001 and r=0.664, p<0.001 respectively, Spearman's test). The samples of Kveim-Siltzbach test reagent contained high levels of β-glucan. Cultures of Propionibacterium ac. and Mycobacterium gordonae contained β-glucan, the levels of which were lower in the Mycobacterium cultures. Comments: The results support the hypothesis that β-glucan, and thus fungal exposure, are involved in the pathogenesis of sarcoidosis. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 130-135).

Crohn's disease and sarcoidosis in siblings: follow-up of a published report with a new case and brief review of the literature

Reported in 1971 were the cases of three brothers, two of whom had developed sarcoidosis and the third Crohn's disease. That now presented concerns one brother who, 50 years after the diagnosis and successful treatment of his sarcoidosis, was found incidentally, at colonoscopy performed to exclude malignancy, to have Crohn's colitis in the absence of any symptoms attributable to this. The report concludes with a brief review of the literature.

Cutaneous Sarcoidosis in a patient with left Hilar calcification of the lungs - A Case Report

Sarcoidosis is an acquired idiopathic granulomatous disease, which is characterized by noncaseating epithelioid granulomas in organs and tissues. Most frequently it affects the lungs, liver, lymph nodes, skin, eyes and other organs. The cutaneous lesions appear in 20 - 30% of patients with systemic manifestations, and in 25% of them they appear without systemic manifestations. Based on the histopathological characteristics, cutaneous lesions are divided into specific, characterized by cutaneous granuloma, and non-specific, which are not granulomatous. Moreover, they can be classified as typical and atypical. We are presenting a female patient with unilateral hilar calcification of the lungs, who exhibited plaque skin lesions typical for sarcoidosis, with a specific granulomatous histology and a favorable response to corticosteroid and antimalarial therapy.

The intersection of microbiome and host at the skin interface: genomic- and metagenomic-based insights

The past two decades have been marked by a surge in research to understand the microbial communities that live in association with the human body, in part stimulated by affordable, high-throughput DNA sequencing technology. In the context of the skin, this Perspective focuses on the current state of genomic- and metagenomic-based host–microbe research and future challenges and opportunities to move the field forward. These include elucidating nonbacterial components of the skin microbiome (i.e., viruses); systematic studies to address common perturbations to the skin microbiome (e.g., antimicrobial drugs, topical cosmetic/hygienic products); improved approaches for identifying potential microbial triggers for skin diseases, including species- and strain-level resolution; and improved, clinically relevant models for studying the functional and mechanistic roles of the skin microbiome. In the next 20 years, we can realistically expect that our knowledge of the skin microbiome will inform the clinical management and treatment of skin disorders through diagnostic tests to stratify patient subsets and predict best treatment modality and outcomes and through treatment strategies such as targeted manipulation or reconstitution of microbial communities.

Saddle nose with sarcoidosis: "A great imitator" of relapsing polychondritis

Sarcoidosis is a systemic granulomatous disease that can affect any organ including the nose. Nasal crusting and congestion are common nasal symptoms of sarcoidosis, whereas cases of saddle-nose deformity are rarely reported. We describe here a case of sarcoidosis that presented with saddle nose resembling relapsing polychondritis. Since sarcoidosis shares clinical features with relapsing polychondritis, the differential diagnosis of saddle nose can be challenging without a clear pathology.

Bilateral Subclavian Vein Occlusion in a SAPHO Syndrome Patient Who Needed an Implantable Cardioverter Defibrillator

A 79-year-old Asian man was hospitalized because of progressive exertional dyspnea with decreasing left ventricular ejection fraction and frequent non-sustained ventricular tachycardia. Pre-procedure venography for implantable cardioverter defibrillator (ICD) implantation showed occlusion of the bilateral subclavian veins. In consideration of subcutaneous humps in the sterno-clavicular area and palmoplantar pustulosis, we diagnosed him as having synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome and speculated that it induced peri-osteal chronic inflammation in the sterno-clavicular area, resulting in occlusion of the adjacent bilateral subclavian veins. An automatic external defibrillator (AED) was installed in the patient's house and total subcutaneous ICD was considered. Venous thrombosis in SAPHO syndrome is not frequent but has been reported. To the best of our knowledge, this is the first case of bilateral subclavian vein occlusion in a SAPHO syndrome patient who needs ICD implantation.

Autophagy Induced by Intracellular Infection of Propionibacterium acnes

Background

Sarcoidosis is caused by Th1-type immune responses to unknown agents, and is linked to the infectious agent Propionibacterium acnes. Many strains of P. acnes isolated from sarcoid lesions cause intracellular infection and autophagy may contribute to the pathogenesis of sarcoidosis. We examined whether P. acnes induces autophagy.

Methods

Three cell lines from macrophages (Raw264.7), mesenchymal cells (MEF), and epithelial cells (HeLa) were infected by viable or heat-killed P. acnes (clinical isolate from sarcoid lymph node) at a multiplicity of infection (MOI) of 100 or 1000 for 1 h. Extracellular bacteria were killed by washing and culturing infected cells with antibiotics. Samples were examined by colony assay, electron-microscopy, and fluorescence-microscopy with anti-LC3 and anti-LAMP1 antibodies. Autophagy-deficient (Atg5^-/-) MEF cells were also used.

Results

Small and large (≥5 μm in diameter) LC3-positive vacuoles containing few or many P. acnes cells (LC3-positive P. acnes) were frequently found in the three cell lines when infected by viable P. acnes at MOI 1000. LC3-positive large vacuoles were mostly LAMP1-positive. A few small LC3-positive/LAMP1-negative vacuoles were consistently observed in some infected cells for 24 h postinfection. The number of LC3-positive P. acnes was decreased at MOI 100 and completely abolished when heat-killed P. acnes was used. LC3-positive P. acnes was not found in autophagy-deficient Atg5^-/- cells where the rate of infection was 25.3 and 17.6 times greater than that in wild-type Atg5^+/+ cells at 48 h postinfection at MOI 100 and 1000, respectively. Electron-microscopic examination revealed bacterial cells surrounded mostly by a single-membrane including the large vacuoles and sometimes a double or multi-layered membrane, with occasional undigested bacterial cells in ruptured late endosomes or in the cytoplasm.

Conclusion

Autophagy was induced by intracellular P. acnes infection and contributed to intracellular bacterial killing as an additional host defense mechanism to endocytosis or phagocytosis.

Genome stability of Propionibacterium acnes: a comprehensive study of indels and homopolymeric tracts

We present a species-wide comparative analysis of 90 genomes of Propionibacterium acnes that represent the known diversity of the species. Our results are augmented by six high-quality genomes and a manual investigation of all gene-sized indels found in the strains. Overall, the order of genes is conserved throughout the species. A public sybil database for easy comparative analysis of the 90 genomes was established. The analysis of indels revealed a total of 66 loci of non-core genes that correlate with phylogenetic clades. No gene was strain-specific in agreement with our conclusion that the P. acnes pan-genome is closed. An exhaustive search for homopolymeric tracts (HPTs) identified a total of 54 variable-length HPTs almost exclusively of guanine/cytosines located between genes or affecting the reading frame of genes. The repeat variation was consistent with phylogenetic clades suggesting slow accumulation over time rather than active modification. By transcriptome analysis we demonstrate how an HPT variation can affect the gene expression levels. Selected cases of both indels and HPTs are described. The catalogued data and the public P. acnes Sybil database provide a solid foundation for generating hypotheses and facilitate comparative genetic analyses in future P. acnes research.