Is there a role for microorganisms in the pathogenesis of sarcoidosis?

Sarcoid-like lesions associated with the immune restoration inflammatory syndrome in AIDS: absence of polymerase chain reaction detection of Mycobacterium tuberculosis in granulomas isolated by laser capture microdissection

Highly active antiretroviral therapy (HAART)-treated human immunodeficiency virus (HIV)-positive patients can develop granulomatous lesions within the first few weeks of initiating therapy. This immune syndrome, called immune restoration inflammatory syndrome (IRIS), can induce sarcoid-like lesions in tissues. The pathogenesis of these granulomas is currently unknown because no pathogen has been identified to date in the lesions using morphological and/or microbiological approaches. However, the role of certain microbes, such as Mycobacterium tuberculosis, is still debated. The aim of this study was to look for the presence of M. tuberculosis in sarcoid-like lesions occurring in 14 AIDS patients treated with HAART. We used the PCR DNA amplification method in granulomas microdissected from sections stained by hematoxylin-eosin from formalin-fixed, paraffin-embedded specimens. Results were compared to those obtained from microdissected tuberculosis (TB) granulomas (15 patients) and from microdissected sarcoidosis granulomas (12 patients). M. tuberculosis DNA was undetectable from the microdissected sarcoid-like granulomas, whereas DNA from M. tuberculosis was isolated in all the microdissected TB granulomas and was absent in the microdissected sarcoidosis granulomas. Taken together, these data showed that M. tuberculosis DNA is not associated with the presence of sarcoid-like lesions occurring in HIV-positive patients treated with HAART.

Transformation of pulmonary histoplasmosis to sarcoidosis: a case report

Histoplasmosis, a dimorphic fungus, and sarcoidosis, a disease of unknown etiology, share many clinical features, including typical manifestations of granulomatous inflammation involving the lungs and mediastinal lymphatics in association with constitutional symptoms. As such, they are often difficult to distinguish based upon clinical presentation. Recent studies suggest that sarcoidosis may be triggered by infectious agents. Here we present a case of documented pulmonary histoplasmosis that evolved into sarcoidosis. This case supports the notion that infections promote sarcoidosis in predisposed hosts.

Toll-like receptor (TLR) 4 polymorphism Asp299Gly is not associated with disease course in Dutch sarcoidosis patients

The aetiology of sarcoidosis, a systemic disorder characterized by the formation of non-caseating granulomas in variable organs, remains enigmatic. Clarification is hampered by heterogeneity in disease phenotypes and course, due partly to the influence of a variety of genetic and environmental factors. Multiple studies have pointed towards bacteria as possible causative agents. Toll-like receptors (TLR) are innate immunity receptors important in the immune response against pathogens. TLR-4, together with CD14 and MD-2, is an essential receptor for the recognition of lipopolysaccharide (LPS), unique to the cell wall of Gram-negative bacteria. Recently, an association between TLR-4 polymorphism Asp299Gly, leading to a change in the extracellular domain of the receptor and possible hyporesponsiveness to LPS, and a chronic course of sarcoidosis was found in German patients. In the present study this polymorphism was genotyped in 156 Dutch sarcoidosis patients and 200 healthy Dutch controls using dual-labelled fluorescent oligonucleotides. No differences were found in allelic distributions between patients and controls (P = 0.79) or within the different clinical entities of the sarcoidosis group (P = 0.44). Importantly, there were no differences between the Dutch and German sarcoidosis patients (P = 0.62). However, the allelic distribution of the Asp299Gly polymorphism differed significantly between both control groups (P = 0.04). This study highlights the importance of testing a reported gene association in a distinct population when performing genetic association studies.

Antifungal treatment in sarcoidosis--a pilot intervention trial

BACKGROUND

Sarcoidosis is generally treated with corticosteroids that are not always an effective therapy.

OBJECTIVES

To assess if treatment with antifungal drugs would improve the clinical status of patients with sarcoidosis.

METHODS

Patients (n=18) with sarcoidosis grades II and III according to established criteria and without clinical and immunological signs of fungal infection, were treated with antifungal medication together with corticosteroids for 3-6 months. Pulmonary X-ray infiltration, lung function, and severity of symptoms were registered before and after the treatment and at follow up 9-58 months later.

RESULTS

The treatment resulted in statistically significant decreases in the degree of pulmonary infiltration with an average decrease in the group from 2.0 to 1.0. There were also significant increases in diffusion capacity and decreases in the severity of symptoms.

CONCLUSION

It is suggested that treatment with antifungal drugs may be useful, at least in certain cases of sarcoidosis.

SAPHO osteomyelitis and sarcoid dermatitis in a patient with DiGeorge syndrome

We report the development and spontaneous resolution of annular erythematous skin lesions consistent with sarcoid dermatitis in a child with DiGeorge syndrome (DGS) carrying the 22q11.2 microdeletion. The skin lesion developed after she was treated with isoniazid (INH) following exposure to active tuberculosis (TB). After resolution of the skin lesions, this child developed sterile hyperplastic osteomyelitis consistent with SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) osteomyelitis in her right mandible triggered by an odontogenic infection. This child had congenital heart disease, dysmorphic facies, recurrent sinopulmonary infection, gastroesophageal reflux disease, scoliosis, reactive periostitis, and developmental delay. She had a low CD4 and CD8 T cell count with a normal 4/8 ratio, but normal cell proliferation and T cell cytokine production in response to mitogens. When she was presented with sterile osteomyelitis of right mandible, she revealed polyclonal hypergammaglobulinemia with elevated erythrocyte sedimentation rate (ESR)/angiotensin converting enzyme (ACE) levels, but negative CRP. Autoimmune and sarcoidosis workup was negative. Inflammatory parameters gradually normalized following resolution of odontogenic infection and with the use of non-steroidal anti-inflammatory drugs (NSAIDs). The broad clinical spectrum of DGS is further expanded with the development of autoimmune and inflammatory complications later in life. This case suggests that patients with the DGS can present with unusual sterile inflammatory lesions triggered by environmental factors, further broadening the clinical spectrum of this syndrome.

Pneumocystis jirovecii colonisation in patients with interstitial lung disease

A prospective study was conducted to determine the prevalence of colonisation by Pneumocystis jirovecii in 80 consecutive patients who required bronchoscopy and bronchoalveolar lavage (BAL) following suspicion of interstitial lung disease (ILD). The mtLSU rRNA gene of P. jirovecii was identified by nested PCR in BAL samples. Patients with ILDs were divided into three groups: group A comprised those with idiopathic interstitial pneumonias; group B comprised those with sarcoidosis; and group C comprised those with other ILDs. The overall prevalence of P. jirovecii carriage was 33.8%, with colonisation rates of 37.8%, 18.8% and 37% in groups A, B and C, respectively (p not significant). There were more smokers among the carriers, but there were no other significant differences between carriers and non-carriers. The high prevalence of P. jirovecii carriers found among immunocompetent patients with ILDs in Spain suggests a possible role of P. jirovecii in the natural history of these diseases.

[Granzymes A and B in pulmonary sarcoidosis (experimental study)]

Sarcoidosis is a systemic disease of unknown aetiology, morphologically characterized by well-formed epithelioid granulomas, which show little or no central necrosis. These may be present in any organ or tissue. The lung is the most frequently and prominently involved target. The granuloma is often very sharply demarcated from the adjacent tissue and is surrounded by a mantle of lymphocytes, which mediate lysis of target cells by various mechanisms, including exocytosis of lytic proteins, perforins and granzymes. Sarcoidosis laboratorial diagnosis is usually made by SACE and Lisozyme dosages. The granzymes A and B could be two other markers of the disease, since the sarcoidosis granuloma is rich in cytotoxic and NK cells. An ELISA Kit was used to measure Granzyme A and B in serum of a normal control group (NC) (n=30), and in two groups with lung pathology: one without sarcoidosis, disease control (DC) (n=21) and other with sarcoidosis (S) (n=11). Our results showed that SACE activity is significantly augmented in S group comparing with NC and DC, respectively: 82,6+/-32,7/31,9+/-17,8 - p=0,00017 and 82,6+/-32,7/31,9+/-17,8 - p=0,00024. Lisozyme activity is significantly augmented in S and DC groups comparing with NC. Granzyme B showed a significant decrease in DC and S groups comparing with NC. Granzyme A showed a significant decrease between S/NC groups. Our results suggest that the decrease of Granzyme A and B in sarcoidotic patients could be related to an ineffective inflammatory local response related to the formation of sarcoidosis granulomas. More studies are needed, particularly in BAL.

CARD15 single nucleotide polymorphisms 8, 12 and 13 are not increased in ethnic Danes with sarcoidosis

BACKGROUND

Mutations of the caspase-activating recruitment domain 15 (CARD15) gene on chromosome 16 are associated with chronic inflammatory granulomatous bowel disease (Crohn's disease). Sarcoidosis is a systemic granulomatous disease with unknown etiology, which shares histological features with Crohn's disease.

OBJECTIVES

To evaluate whether ethnic Danes with sarcoidosis have an increased frequency of CARD15 mutations compared to healthy control subjects.

METHODS

Genotyping for CARD15 mutations R702W, G908R, and L1007fsinsC, also designated single nucleotide polymorphism (SNP) SNP8, SNP12 and SNP13, respectively, were performed by capillary electrophoresis single-strand confirmation polymorphism in 53 patients with histologically verified sarcoidosis and in 103 healthy controls.

RESULTS

The frequencies of CARD15 mutations in sarcoidosis patients were: SNP8, 4/106 chromosomes (3.8%); SNP12, 2/106 chromosomes (1.9%); SNP13, 2/106 chromosomes (1.9%); SNP8+SNP12+SNP13, 8/106 chromosomes (7.6%). All 8 patients were heterozygous. The frequencies in controls were: SNP8, 9/206 chromosomes (4.4%); SNP12, 2/206 chromosomes (1.0%); SNP13, 4/206 chromosomes (1.9%); SNP8+SNP12+SNP13, 15/206 chromosomes (7.3%). All controls were heterozygous. The differences were not statistically significant (p>0.05). Furthermore, the course of disease was not significantly different in the 8 patients with CARD15 mutations and the 45 patients without mutations.

CONCLUSION

The frequency of CARD15 mutations is not increased in ethnic Danish patients with sarcoidosis, and heterozygosity for such mutations apparently has no influence on the course of disease.

Sweet's syndrome and sarcoidosis

In this review we summarize a number of cases of Sweet's syndrome (SS) associated with sarcoidosis that have been reported in the English literature. In all of the cases, the two disorders were diagnosed simultaneously. Patients with both disorders were younger and had a higher rate of fever than patients with SS alone. In this group of patients, we found a trend toward less skin involvement of the face and trunk, more involvement of the upper limbs, and more atypical skin lesions, particularly papules. The association of the two disorders seems to be more related to a subset of acute sarcoidosis (Lofgren's syndrome). All of the patients in this group had a benign course and self-limiting disease. Thus, SS in association with sarcoidosis could be considered a favorable prognostic factor. Although SS has a high rate of recurrence, no recurrence occurred in this group of patients during follow-up.

Endotoxin Up-regulates Interleukin-18

RATIONALE AND OBJECTIVES

Sarcoidosis is a granulomatous disease of unknown etiology characterized by a helper T-cell type 1-mediated process. Previously we demonstrated a role for interleukin-18 in sarcoidosis. Here we examine the regulation of interleukin-18 in this condition.

METHODS

Cytokine levels in sarcoid epithelial lining fluid were measured by ELISA. We examined interleukin-18 promoter activity and mRNA and protein levels in the epithelial lining fluid of individuals with active sarcoidosis, and of individuals recovered from sarcoidosis, in response to purified protein derivative of Mycobacterium tuberculosis, beryllium sulfate, zirconium sulfate, aluminum sulfate, and lipopolysaccharide. Endotoxin levels in the epithelial lining fluid of individuals with sarcoidosis, individuals recovered from sarcoidosis, and control subjects were assessed by Limulus amebocyte lysate analysis. Allele-specific polymerase chain reaction was used to genotype 94 patients with sarcoidosis and 97 control subjects for the interleukin-18 -607(A/C) polymorphism. Species-specific polymerase chain reaction identified bacterial DNA in fluid samples.

RESULTS

Epithelial lining fluid from active sarcoids contained elevated levels of interleukin-18, interferon-gamma, and interleukin-12 compared with recovered patients and also contained significantly higher levels of endotoxin. Depletion of endotoxin from this epithelial lining fluid reduced its effect on the human interleukin-18 promoter in vitro. There was a higher frequency of the -607C allele and -607(C/C) genotype in the sarcoidosis population compared with control subjects; however, this was not associated with a functional response to endotoxin treatment. Finally, bacterial 16S rRNA from Haemophilus influenzae and Moraxella catarrhalis was detected in sarcoid fluid samples.

CONCLUSIONS

The pathogenesis of sarcoidosis is propagated through the actions of a helper T-cell type 1-driven response. This study shows that gram-negative bacteria may contribute to this effect by upregulating interleukin-18 expression.

Characterization of Mycobacterium tuberculosis complex isolates from Greek patients with sarcoidosis by Spoligotyping

Spoligotyping was undertaken with 38 Mycobacterium tuberculosis isolates from Greek sarcoidosis patients and 31 isolates from patients with tuberculosis. Fifty percent of the isolates from sarcoidosis patients and 16.13% of the isolates from patients with tuberculosis were represented by a unique pattern, whereas the remaining isolates belonged to seven shared types. Interestingly, half of the isolates from sarcoidosis patients did not resemble the spoligotypes of the isolates from patients with tuberculosis, most of which pertained to shared spoligotypes.

High prevalence of Mycobacterium tuberculosis DNA in biopsies from sarcoidosis patients from Catalonia, Spain

BACKGROUND

Sarcoidosis is a systemic granulomatous disease of unknown etiology. The presence of mycobacterial nucleic acid components in patients with sarcoidosis has been demonstrated with varying degrees of success.

OBJECTIVES

The aim of this study was to estimate the presence of Mycobacterium tuberculosis DNA in tissues from sarcoidosis patients, in Catalonia, Spain, as well as to assess the long-term clinical course in these patients.

METHODS

Fifty-eight paraffin-embedded tissue biopsies corresponding to cases of sarcoidosis (n = 23), lung neoplasm (n = 23), and lung tuberculosis (n = 12) available in 1996 were analyzed in a retrospective study by means of a nested polymerase chain reaction using primers corresponding to the insertion element IS6110 of M. tuberculosis complex. For greater sensitivity, Southern blot hybridization was performed. Clinical data were recorded prior to and after PCR analysis (follow-up reported until 2002).

RESULTS

M. tuberculosis DNA was present in 9 out of 23 sarcoidosis biopsies (39%), in 1 out of 23 control patients (4%) (p < 0.01), and in all tissue samples from the 12 control patients with tuberculosis. To date, none of these sarcoidosis patients has developed tuberculosis over a mean (+/-SD) follow-up period of 11 (+/-3.4) years.

CONCLUSION

In our setting, M. tuberculosis DNA is present in tissue biopsies of significantly more sarcoidosis patients than controls. However, these results do not demonstrate causality, although they may suggest a link between M. tuberculosis infection and sarcoidosis in some cases. Follow-up of these patients suggests that M. tuberculosis-DNA-positive sarcoidosis patients are not at greater risk of developing tuberculosis than M. tuberculosis-DNA-negative patients.

[Update on sarcoidosis]

Since the first description more than a century ago, intensive research continues to focus on sarcoidosis. Based on our current knowledge, sarcoidosis can be considered as an immune syndrome resulting from a variable combination of predisposing genetic, ethnic, and environmental factors. Over the last few years, several teams have proposed a link between certain genetic polymorphisms, particularly of the HLA system, and the risk of development or progression of sarcoidosis. Other pathogenic mechanisms involved in the formation of the sarcoid granuloma are becoming more clear and have led to the development of new therapeutic approaches such as anti-TNF currently being evaluated in multicentric trials.

Pulmonary sarcoidosis

Sarcoidosis is a multisystemic disease of unknown aetiology characterized by the formation of immune granulomas in involved organs. It is a worldwide disease that mainly affects 25-40 years old people with a lifetime incidence rate of 0.85-2.4%. Multiple clinical phenotypes are observed according to presentation, involved organs, disease duration and severity. Sarcoidosis primarily affects the lungs and the lymphatic system. The prevailing pathogenic hypothesis is that various antigens could promote sarcoidosis in genetically susceptible hosts, both these factors modulating the incidence and the clinical phenotype of sarcoidosis. So far, environmental agents have been suspected, including possible mycobacteria and propionibacteria. Interferon-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)-12 and IL-18 play a critical role in driving the Th1 commitment in the course of granulomatous process. Evolution of sarcoidosis is often marked by spontaneous resolution within 12-36 months, but can be severe because of chronic cases with pulmonary fibrosis or involving other organs, including heart, central nervous system and eyes. Mortality, ranging between 0.5 and 5%, is most often related to pulmonary fibrosis. Corticosteroids can reverse the granulomatous process, but are only suspensive, and their long-term benefit remains under question. Corticosteroids are recommended when sarcoidosis shows unfavourable clinical tolerance and evolution. Alternative and corticosteroid-sparing therapies are of increased interest in difficult cases, while targeted new drugs such as anti-TNF-alpha are still under investigation.

Mycobacterial catalase-peroxidase is a tissue antigen and target of the adaptive immune response in systemic sarcoidosis

Sarcoidosis is a disease of unknown etiology characterized by noncaseating epithelioid granulomas, oligoclonal CD4(+) T cell infiltrates, and immune complex formation. To identify pathogenic antigens relevant to immune-mediated granulomatous inflammation in sarcoidosis, we used a limited proteomics approach to detect tissue antigens that were poorly soluble in neutral detergent and resistant to protease digestion, consistent with the known biochemical properties of granuloma-inducing sarcoidosis tissue extracts. Tissue antigens with these characteristics were detected with immunoglobulin (Ig)G or F(ab')(2) fragments from the sera of sarcoidosis patients in 9 of 12 (75%) sarcoidosis tissues (150-160, 80, or 60-64 kD) but only 3 of 22 (14%) control tissues (all 62-64 kD; P = 0.0006). Matrix-assisted laser desorption/ionization time of flight mass spectrometry identified Mycobacterium tuberculosis catalase-peroxidase (mKatG) as one of these tissue antigens. Protein immunoblotting using anti-mKatG monoclonal antibodies independently confirmed the presence of mKatG in 5 of 9 (55%) sarcoidosis tissues but in none of 14 control tissues (P = 0.0037). IgG antibodies to recombinant mKatG were detected in the sera of 12 of 25 (48%) sarcoidosis patients compared with 0 of 11 (0%) purified protein derivative (PPD)(-) (P = 0.0059) and 4 of 10 (40%) PPD(+) (P = 0.7233) control subjects, suggesting that remnant mycobacterial catalase-peroxidase is one target of the adaptive immune response driving granulomatous inflammation in sarcoidosis.

Neurosarcoidosis

Neurosarcoidosis is an uncommon presentation of sarcoidosis. It is associated with significant morbidity and poor outcome. In the past decade, there has been significant progress in our understanding of the immunopathogenesis of the disease, but the etiology of this enigmatic condition still eludes us. Improved insight has paved the way for development of different treatment strategies against critical immunologic stages of the disease.

Granulomatous diseases of the oral tissues: differential diagnosis and update

Because of the relatively nonspecific clinical findings associated with a variety of granulomatous diseases, a microscopic diagnosis of granulomatous inflammation often presents a diagnostic dilemma for the clinician. The most common differential diagnosis includes foreign body reactions, infection, Crohn's disease, sarcoidosis, and orofacial granulomatosis. However, a variety of other conditions may be associated with granuloma formation. Often an extensive clinical, microscopic, and laboratory evaluation may be required to identify the source of the granulomatous inflammation. This article highlights the origin, clinical manifestations, current diagnostic modalities, and treatment of specific granulomatous diseases that may be encountered in clinical practice.

Exacerbation of underlying pulmonary disease in pregnancy

This article examines the management and outcomes of pregnant women with cystic fibrosis, primary pulmonary hypertension, and sarcoidosis. Pregnancy and the puerperium are associated with important cardiopulmonary changes that can adversely affect the clinical condition. Management of pregnant women with CF should be done with careful attention to complications of altered body weight, diabetes, and liver disease. Primary pulmonary hypertension is characterized by a progressive increase in pulmonary pressure and resistance in the absence of an identified cardiac or pulmonary cause. A multidisciplinary approach to the management of patients with primary pulmonary hypertension is of great importance for a successful maternal and fetal outcome. Good maternal and fetal outcomes are possible in women with restrictive lung disease in general and sarcoidosis in particular. The management of pregnancy, labor, and delivery are not altered by the presence of sarcoidosis.

Clinical and immunologic components of sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that affects the lungs and the lymphatic system. It is seen by specialists in allergy, rheumatology, and pulmonary disease. Although there are no clues to etiology, an environmental basis has been implicated primarily on the basis of epidemiologic and anecdotal data. The majority of patients are very readily diagnosed and should not be confused with other pulmonary disorders. Sarcoidosis can become an issue if it occurs in the presence of other significant pulmonary disease, such as patients with asthma or hypersensitivity pneumonitis. Most patients remain asymptomatic and many are diagnosed when picked up on a routine screening exam. Steroids can be used to manage some patients but caution should be exercised to choose the appropriate dose and to treat patients for a limited period of time to avoid the complications of steroids. A minority of patients do progress to significant disease, including morbidity and mortality, and further research is needed to determine more appropriate and specific therapy for such situations.

Sarcoidosis in untreated chronic hepatitis C virus infection

Chronic hepatitis C has been implicated in the pathogenesis of sarcoidosis in several cases of patients treated with interferon-alpha. On the other hand, only in a few cases previously has a possible link between sarcoidosis and untreated chronic hepatitis C virus infection been demonstrated. We report on a patient with chronic hepatitis C who developed cutaneous sarcoidosis without prior interferon-alpha treatment. We hypothesize that viral persistence seen in chronic hepatitis C virus infection might be one of the potential factors that trigger cellular immune response in granulomatous reactions as seen in sarcoidosis, in genetically predisposed patients.