Etiologic link between sarcoidosis and Propionibacterium acnes

P. acnes-Driven Disease Pathology: Current Knowledge and Future Directions

This review discusses the biology and behavior of Propionibacterium acnes (P. acnes), a dominant bacterium species of the skin biogeography thought to be associated with transmission, recurrence and severity of disease. More specifically, we discuss the ability of P. acnes to invade and persist in epithelial cells and circulating macrophages to subsequently induce bouts of sarcoidosis, low-grade inflammation and metastatic cell growth in the prostate gland. Finally, we discuss the possibility of P. acnes infiltrating the brain parenchyma to indirectly contribute to pathogenic processes in neurodegenerative disorders such as those observed in Parkinson's disease (PD).

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.

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.

Solitary tentorial sarcoid granuloma associated with Propionibacterium acnes infection: case report

Sarcoidosis is a systemic granulomatous disease with unknown cause, which very rarely occurs exclusively in the central nervous system. The authors performed biopsy sampling of a mass that developed in the left tentorium cerebelli that appeared to be a malignant tumor. The mass was diagnosed as a sarcoid granuloma, which was confirmed with the onset of antibody reaction product against Propionibacterium acnes. Findings suggesting sarcoidosis to be an immune response to P. acnes infection have recently been reported, and they give insight for diagnosis and treatment of this disease. The authors report the possible first case that was confirmed with P. acnes infection in a meningeal lesion in solitary neurosarcoidosis.

Animal models of sarcoidosis

Sarcoidosis is a debilitating, inflammatory, multiorgan, granulomatous disease of unknown cause, commonly affecting the lung. In contrast to other chronic lung diseases such as interstitial pulmonary fibrosis or pulmonary arterial hypertension, there is so far no widely accepted or implemented animal model for this disease. This has hampered our insights into the etiology of sarcoidosis, the mechanisms of its pathogenesis, the identification of new biomarkers and diagnostic tools and, last not least, the development and implementation of novel treatment strategies. Over past years, however, a number of new animal models have been described that may provide useful tools to fill these critical knowledge gaps. In this review, we therefore outline the present status quo for animal models of sarcoidosis, comparing their pros and cons with respect to their ability to mimic the etiological, clinical and histological hallmarks of human disease and discuss their applicability for future research. Overall, the recent surge in animal models has markedly expanded our options for translational research; however, given the relative early stage of most animal models for sarcoidosis, appropriate replication of etiological and histological features of clinical disease, reproducibility and usefulness in terms of identification of new therapeutic targets and biomarkers, and testing of new treatments should be prioritized when considering the refinement of existing or the development of new models.

Emendation of Propionibacterium acnes subsp. acnes (Deiko et al. 2015) and proposal of Propionibacterium acnes type II as Propionibacterium acnes subsp. defendens subsp. nov

Recently, it has been proposed that strains of Propionibacterium acnes from the type III genetic division should be classified as P. acnessubsp. elongatum subsp. nov., with strains from the type I and II divisions collectively classified as P. acnessubsp. acnes subsp. nov. Under such a taxonomic re-appraisal, we believe that types I and II should also have their own separate rank of subspecies. In support of this, we describe a polyphasic taxonomic study based on the analysis of publicly available multilocus and whole-genome sequence datasets, alongside a systematic review of previously published phylogenetic, genomic, phenotypic and clinical data. Strains of types I and II form highly distinct clades on the basis of multilocus sequence analysis (MLSA) and whole-genome phylogenetic reconstructions. In silico or digital DNA-DNA similarity values also fall within the 70-80 % boundary recommended for bacterial subspecies. Furthermore, we see important differences in genome content, including the presence of an active CRISPR/Cas system in type II strains, but not type I, and evidence for increasing linkage equilibrium within the separate divisions. Key biochemical differences include positive test results for β-haemolytic, neuraminidase and sorbitol fermentation activities with type I strains, but not type II. We now propose that type I strains should be classified as P. acnessubsp. acnes subsp. nov., and type II as P. acnessubsp. defendens subsp. nov. The type strain of P. acnessubsp. acnes subsp. nov. is NCTC 737T (=ATCC 6919T=JCM 6425T=DSM 1897T=CCUG 1794T), while the type strain of P. acnessubsp. defendens subsp. nov. is ATCC 11828 (=JCM 6473=CCUG 6369).

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.

Etiologies of Sarcoidosis

Since sarcoidosis was first described more than a century ago, the etiologic determinants causing this disease remain uncertain. Studies suggest that genetic, host immunologic, and environmental factors interact together to cause sarcoidosis. Immunologic characteristics of sarcoidosis include non-caseating granulomas, enhanced local expression of T helper-1 (and often Th17) cytokines and chemokines, dysfunctional regulatory T-cell responses, dysregulated Toll-like receptor signaling, and oligoclonal expansion of CD4+ T cells consistent with chronic antigenic stimulation. Multiple environmental agents have been suggested to cause sarcoidosis. Studies from several groups implicate mycobacterial or propionibacterial organisms in the etiology of sarcoidosis based on tissue analyses and immunologic responses in sarcoidosis patients. Despite these studies, there is no consensus on the nature of a microbial pathogenesis of sarcoidosis. Some groups postulate sarcoidosis is caused by an active viable replicating infection while other groups contend there is no clinical, pathologic, or microbiologic evidence for such a pathogenic mechanism. The authors posit a novel hypothesis that proposes that sarcoidosis is triggered by a hyperimmune Th1 response to pathogenic microbial and tissue antigens associated with the aberrant aggregation of serum amyloid A within granulomas, which promotes progressive chronic granulomatous inflammation in the absence of ongoing infection.

Simultaneous development of sarcoidosis and cutaneous vasculitis in a patient with refractory Crohn's disease during infliximab therapy

Background

Paradoxical inflammations during anti-TNF-α therapy are defined as adverse effects such as psoriasiform skin lesions, uveitis and sarcoidosis-like granulomas induced by immune reactions, not by infectious agents. Here, we report a very rare case of the simultaneous development of sarcoidosis and cutaneous vasculitis in a patient with refractory Crohn’s disease during infliximab therapy and both of which resolved spontaneously without the cessation of infliximab.

Case presentation

In September 2000, 23-year old Japanese male was diagnosed with Crohn’s disease. Prednisolone in combination with mesalazine was introduced at first and succeeded for almost one year. In June 2002, since his gastrointestinal symptoms relapsed and were refractory, infliximab (IFX) therapy 5 mg/kg was introduced. In February 2011, because he had repeated arthralgia almost every intravenous IFX administration, IFX was increased to 10 mg/kg under the diagnosis of a secondary failure of IFX. In December 2012, he complained of slight dry cough and an itchy eruption on both lower limbs, and he was referred to our hospital due to the appearance of bilateral hilar lymphadenopathy on chest X-ray examination. Chest computed tomogram revealed bilateral hilar lymphadenopathy and fine reticulonodular shadows on the bilateral upper lungs. Serum calcium, angiotensin-converting enzyme and soluble interleukin 2 receptor levels were not elevated, but the titer of antinuclear antibody was considerably elevated. Mycobacterium infection was carefully excluded. Trans-bronchial lung biopsy showed non-caseating epithelioid cell granulomas compatible with sarcoidosis. The skin biopsy of the right limb was diagnosed as leukocytoclastic vasculitis. The patient was diagnosed as having a series of paradoxical inflammations during anti-TNF-α therapy. Since his paradoxical inflammations were not severe and opportunistic infections were excluded, IFX was cautiously continued for refractory Crohn’s disease. Nine months later, not only his intrathoracic lesions but also his cutaneous lesions had spontaneously resolved.

Conclusion

Physicians caring for patients with anti-TNF-α therapy should know that, based on a careful exclusion of infectious agents and thoughtful assessment of the patient’s possible risks and benefits, paradoxical inflammations can be resolved without the cessation of anti-TNF-α therapy.

Pulmonary mucosa-associated lymphoid tissue lymphoma associated with pulmonary sarcoidosis: a case report and literature review

Differentiating low-grade lymphoma from preexisting sarcoidosis is difficult because of their pathological similarity. This article describes a case of pulmonary mucosa-associated lymphoid tissue lymphoma associated with pulmonary sarcoidosis. The patient, a 45-year-old Japanese man, presented with a 10-year history of pulmonary sarcoidosis and 5-year history of ocular sarcoidosis with histologic findings. Because only the right S3 lung nodule had gradually enlarged, partial resection was performed. Pathological study revealed noncaseous epithelioid granulomas with lymphoplasmacytic proliferation but also marked lymphoid cell proliferation with lymphoepithelial lesion findings that differed from findings of typical sarcoid lesions. Our lymphoepithelial lesion evaluation via immunohistochemistry and analysis of Ig heavy-chain gene rearrangements with assessment of Propionibacterium acnes-specific antibody reactions allow us to report, for the first time, this case of pulmonary mucosa-associated lymphoid tissue lymphoma associated with pulmonary sarcoidosis in exactly the same location, which may be significant for differentiating these diseases and understanding their pathogenic association.

Obesity and chronic pain: systematic review of prevalence and implications for pain practice

The combination of obesity and pain may worsen a patient's functional status and quality of life more than each condition in isolation. We systematically searched PubMed/MEDLINE and the Cochrane databases for all reports published on obesity and pain. The prevalence of combined obesity and pain was substantial. Good evidence shows that weight reduction can alleviate pain and diminish pain-related functional impairment. However, inadequate pain control can be a barrier to effective lifestyle modification and rehabilitation. This article examines specific pain management approaches for obese patients and reviews novel interventional techniques for treatment of obesity. The infrastructure for simultaneous treatment of obesity and pain already exists in pain medicine (eg, patient education, behavioral medicine approaches, physical rehabilitation, medications, and interventional treatment). Screening for obesity, pain-related disability, and behavioral disorders as well as monitoring of functional performance should become routine in pain medicine practices. Such an approach requires additional physician and staff training. Further research should focus on better understanding the interplay between these 2 very common conditions and the development of effective treatment strategies.

Targeting CD4(+) T cells for the treatment of sarcoidosis: a promising strategy?

Sarcoidois is an inflammatory disease of unknown origin characterized by the abnormal accumulation of noncaseating granulomas at sites of disease activity in multiple organs throughout the body with a predilection for the lungs. Because the exact trigger that leads to disease activity is still under investigation, current treatment options are contingent on the organ or organs affected. Corticosteroids are the therapy of choice, but antimalarials and TNF-α antagonists are also commonly prescribed. Recent findings provide evidence for the use of CD20 B-cell-depleting therapy as an alternative method of choice. However, because sarcoidosis is predominantly a T-helper cell-driven disorder, an overwhelming amount of compelling evidence exists for the use of CD4(+) T-cell targeted therapy.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Genetic profiles of Propionibacterium acnes and identification of a unique transposon with novel insertion sequences in sarcoid and non-sarcoid isolates

Propionibacterium acnes is one of the most commonly implicated etiologic agents of sarcoidosis. We previously reported a complete genome sequence of the C1 strain of P. acnes as a clinical isolate from subcutaneous granulomatous inflammatory lesions in a patient with sarcoidosis. In the present study, we initially searched for genetic profiles specific to the C1 strain by core genome analysis and multiple genome alignment with database sequences from 76 and 9 P. acnes strains, respectively. The analysis revealed that the C1 strain was phylogenetically independent and carried an 18.8-kbp transposon sequence unique to the sarcoid isolate. The unique composite transposon comprised a novel insertion sequence and extrinsic genes from bacteria other than P. acnes. Multilocus sequence typing using 24 sarcoid and 36 non-sarcoid isolates revealed a total of 28 sequence types (STs), including ST26, which was most frequently found without specificity for sarcoid isolates. All 13 ST26 isolates exhibited cell-invasiveness and were confirmed to carry the novel insertion sequence and 4 of the 27 extrinsic CDSs in the transposon, with one exception. ST26 of P. acnes with the composite transposon is the most unique strain detected to date and should be further examined as a causative strain of sarcoidosis.

Multiplex touchdown PCR for rapid typing of the opportunistic pathogen Propionibacterium acnes

The opportunistic human pathogen Propionibacterium acnes is composed of a number of distinct phylogroups, designated types IA1, IA2, IB, IC, II, and III, which vary in their production of putative virulence factors, their inflammatory potential, and their biochemical, aggregative, and morphological characteristics. Although multilocus sequence typing (MLST) currently represents the gold standard for unambiguous phylogroup classification and individual strain identification, it is a labor-intensive and time-consuming technique. As a consequence, we developed a multiplex touchdown PCR assay that in a single reaction can confirm the species identity and phylogeny of an isolate based on its pattern of reaction with six primer sets that target the 16S rRNA gene (all isolates), ATPase (types IA1, IA2, and IC), sodA (types IA2 and IB), atpD (type II), and recA (type III) housekeeping genes, as well as a Fic family toxin gene (type IC). When applied to 312 P. acnes isolates previously characterized by MLST and representing types IA1 (n=145), IA2 (n=20), IB (n=65), IC (n=7), II (n=45), and III (n=30), the multiplex displayed 100% sensitivity and 100% specificity for detecting isolates within each targeted phylogroup. No cross-reactivity with isolates from other bacterial species was observed. This multiplex assay will provide researchers with a rapid, high-throughput, and technically undemanding typing method for epidemiological and phylogenetic investigations. It will facilitate studies investigating the association of lineages with various infections and clinical conditions, and it will serve as a prescreening tool to maximize the number of genetically diverse isolates selected for downstream higher-resolution sequence-based analyses.

An extremely unusual presentation of isolated extrathoracic sarcoidosis of submandibular lymph node in a child

A 12-year-old male child presented with left submandibular lymphadenopathy; excision biopsy revealed noncaseating granuloma with numerous Schaumann bodies in histopathology, suggestive of isolated extrathoracic sarcoidosis, which is an extremely rare entity in the pediatric age group.

Interleukin-12 family cytokines and sarcoidosis

Sarcoidosis is a systemic granulomatous disease predominantly affecting the lungs. It is believed to be caused by exposure to pathogenic antigens in genetically susceptible individuals but the causative antigen has not been identified. The formation of non-caseating granulomas at sites of ongoing inflammation is the key feature of the disease. Other aspects of the pathogenesis are peripheral T-cell anergy and disease progression to fibrosis. Many T-cell-associated cytokines have been implicated in the immunopathogenesis of sarcoidosis, but it is becoming apparent that IL-12 cytokine family members including IL-12, IL-23, IL-27, and IL-35 are also involved. Although the members of this unique cytokine family are heterodimers of similar subunits, their biological functions are very diverse. Whilst IL-23 and IL-12 are pro-inflammatory regulators of Th1 and Th17 responses, IL-27 is bidirectional for inflammation and the most recent family member IL-35 is inhibitory. This review will discuss the current understanding of etiology and immunopathogenesis of sarcoidosis with a specific focus on the bidirectional impact of IL-12 family cytokines on the pathogenesis of sarcoidosis.

Intracellular Propionibacterium acnes infection in glandular epithelium and stromal macrophages of the prostate with or without cancer

Background

Recent reports on Propionibacterium acnes (P. acnes) suggest that this bacterium is prevalent in the prostate, is associated with acute and chronic prostatic inflammation, and might have a role in prostate carcinogenesis.

Methods

To evaluate the pathogenic role of this indigenous bacterium, we screened for the bacterium in radical prostatectomy specimens using enzyme immunohistochemistry with a novel P. acnes-specific monoclonal antibody (PAL antibody), together with an anti-nuclear factor-kappa B (NF-κB) antibody. We examined formalin-fixed and paraffin-embedded tissue sections of radical prostatectomy specimens from 28 patients with prostate cancer and 18 age-matched control patients with bladder cancer, but without prostate cancer.

Results

Immunohistochemistry with the PAL antibody revealed small round bodies within some non-cancerous glandular epithelium and stromal macrophages in most prostate samples. Prostate cancer samples had higher frequencies of either cytoplasmic P. acnes or nuclear NF-κB expression of glandular epithelium and higher numbers of stromal macrophages with P. acnes than control samples. These parameters were also higher in the peripheral zone than in the transitional zone of the prostate, especially in prostate cancer samples. Nuclear NF-κB expression was more frequent in glands with P. acnes than in glands without P. acnes. The number of stromal macrophages with the bacterium correlated with the grade of chronic inflammation in both the PZ and TZ areas and with the grade of acute inflammation in the TZ area.

Conclusions

Immunohistochemical analysis with a novel monoclonal antibody for detecting P. acnes in the prostate suggested that intraepithelial P. acnes infection in non-cancerous prostate glands and inflammation caused by the bacterium may contribute to the development of prostate cancer.

Editorial on two chronic low back pain studies: A major change in surgical management of disc disease?

In two recent publications, the authors’ hypothesis was that Modic type 1 changes seen in patients with chronic low back pain and herniated lumbar discs may be attributed to bacterial infection/inflammation. The first study showed that many herniated discs were infected with Proprionibacterium acnes, a common anaerobic skin organism, also found in sarcoidosis, and possibly, arthritic joints. In the second double-blind randomized study, 162 patients with disc herniation and Modic type 1 changes were treated with 100 days of oral Bioclavid (Amoxicillin/Clavulanic acid) vs. placebo; those treated with antibiotics improved in all dimensions (e.g., reduced chronic low back/leg pain, reduced disability). Together, the implications of these studies for spine surgeons and pain practitioners are momentous. If a few weeks of oral antibiotic treatment resolves chronic low back pain, then much currently performed spine surgery (e.g. including internal fixation/fusion), as well as chronic pain management/rehabilitation and psychological strategies may be rendered unnecessary.