Genetics of sarcoidosis

Sarcoid Uveitis: An Intriguing Challenger

The purpose of our work is to describe the actual knowledge concerning etiopathogenesis, clinical manifestations, diagnostic procedures, complications and therapy of ocular sarcoidosis (OS). The study is based on a recent literature review and on the experience of our tertiary referral center. Data were retrospectively analyzed from the electronic medical records of 235 patients (461 eyes) suffering from a biopsy-proven ocular sarcoidosis. Middle-aged females presenting bilateral ocular involvement are mainly affected; eye involvement at onset is present in one-third of subjects. Uveitis subtype presentation ranges widely among different studies: panuveitis and multiple chorioretinal granulomas, retinal segmental vasculitis, intermediate uveitis and vitreitis, anterior uveitis with granulomatous mutton-fat keratic precipitates, iris nodules, and synechiae are the main ocular features. The most important complications are cataract, glaucoma, cystoid macular edema (CME), and epiretinal membrane. Therapy is based on the disease localization and the severity of systemic or ocular involvement. Local, intravitreal, or systemic steroids are the mainstay of treatment; refractory or partially responsive disease has to be treated with conventional and biologic immunosuppressants. In conclusion, we summarize the current knowledge and assessment of ophthalmological inflammatory manifestations (mainly uveitis) of OS, which permit an early diagnostic assay and a prompt treatment.

Sarcoidosis during treatment of pulmonary tuberculosis: a rare case report and review of the literature

The coexistence of pulmonary tuberculosis and pulmonary sarcoidosis is rare. Further, the morphological features of pulmonary tuberculosis with comorbid pulmonary sarcoidosis are similar to those of tuberculosis alone. There are obvious clinical, histological, and radiological similarities between sarcoidosis and tuberculosis, which makes differential diagnosis very challenging, particularly in countries with a high burden of tuberculosis. Here, a rare case of computed tomography (CT) findings of sarcoidosis that developed during tuberculosis treatment is reported. The 46-year-old male patient had no significant symptoms and was undergoing treatment for Mycobacterium tuberculosis infection. Chest CT revealed enlargement of multiple lymph nodes, without cystic or necrotic changes, in the mediastinum and both hili, and post-infectious changes consistent with the sequelae of tuberculosis infection in the left upper lobe. Chest radiographic evidence was accompanied by compatible clinical features and noncaseating granulomas on biopsy. As the patient was clinically stable, corticosteroid treatment was not initiated. To date, the patient remains without specific symptoms and outpatient follow-ups continue. Although rare, sarcoidosis may occur during treatment of pulmonary tuberculosis, and requires attention for diagnosis and treatment. The present case draws a radiological picture of how tuberculosis evolved to sarcoidosis.

Soluble epoxide hydrolase derived lipid mediators are elevated in bronchoalveolar lavage fluid from patients with sarcoidosis: a cross-sectional study

Background

Sarcoidosis is a systemic inflammatory multi-organ disease almost always affecting the lungs. The etiology remains unknown, but the hallmark of sarcoidosis is formation of non-caseating epithelioid cells granulomas in involved organs. In Scandinavia, > 30% of sarcoidosis patients have Löfgren’s syndrome (LS), an acute disease onset mostly indicating a favorable prognosis. The impact of dysregulation of lipid mediators, which has been investigated in other inflammatory disorders, is still unknown.

Methods

Using three different liquid chromatography coupled to tandem mass spectrometry targeted platforms (LC-MS/MS), we quantified a broad suite of lipid mediators including eicosanoids, sphingolipids and endocannabinoids in bronchoalveolar lavage (BAL) fluid from pulmonary sarcoidosis patients (n = 41) and healthy controls (n = 16).

Results

A total of 47 lipid mediators were consistently detected in BAL fluid of patients and controls. After false discovery rate adjustment, two products of the soluble epoxide hydrolase (sEH) enzyme, 11,12-dihydroxyeicosa-5,8,14-trienoic acid (11,12-DiHETrE, p = 4.4E-5, q = 1.2E-3, median fold change = 6.0) and its regioisomer 14,15-dihydroxyeicosa-5,8,11-trienoic acid (14,15-DiHETrE, p = 3.6E-3, q = 3.2E-2, median fold change = 1.8) increased in patients with sarcoidosis. Additional shifts were observed in sphingolipid metabolism, with a significant increase in palmitic acid-derived sphingomyelin (SM16:0, p = 1.3E-3, q = 1.7E-2, median fold change = 1.3). No associations were found between these 3 lipid mediators and LS, whereas levels of SM 16:0 and 11,12-DiHETrE associated with radiological stage (p < 0.05), and levels of 14,15-DiHETrE were associated with the BAL fluid CD4/CD8 ratio.

Conclusions

These observed shifts in lipid mediators provide new insights into the pathobiology of sarcoidosis and in particular highlight the sEH pathway to be dysregulated in disease.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0939-0) contains supplementary material, which is available to authorized users.

Prediction of Disordered Regions and Their Roles in the Anti-Pathogenic and Immunomodulatory Functions of Butyrophilins

Butyrophilins (BTNs) are a group of the moonlighting proteins, some members of which are secreted in milk. They constitute a large family of structurally similar type 1 transmembrane proteins from the immunoglobulin superfamily. Although the founding member of this family is related to lactation, participating in the secretion, formation and stabilization of milk fat globules, it may also have a cell surface receptor function. Generally, the BTN family members are known to modulate co-stimulatory responses, T cell selection, differentiation, and cell fate determination. Polymorphism of these genes was shown to be associated with the pathology of several human diseases. Despite their biological significance, structural information on human butyrophilins is rather limited. Based on their remarkable multifunctionality, butyrophilins seem to belong to the category of moonlighting proteins, which are known to contain intrinsically disordered protein regions (IDPRs). However, the disorder status of human BTNs was not systematically investigated as of yet. The goal of this study is to fill this gap and to evaluate peculiarities of intrinsic disorder predisposition of the members of human BTN family, and to find if they have IDPRs that can be attributed to the multifunctionality of these important proteins.

FCGR3A and FCGR3B copy number variations are risk factors for sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder that causes significant morbidity. Genetic factors contribute to sarcoidosis risks. In this study, we investigated whether copy number variations (CNVs) of FCGR3A (coding for FcγRIIIA) and FCGR3B (coding for FcγRIIIB) genes are associated with sarcoidosis susceptibility and whether the expressions of FcγRIIIA on NK cells and FcγRIIIB on neutrophils are altered in sarcoidosis patients. TaqMan real-time PCR assays were used to analyze the CNV of FCGR3A and FCGR3B genes. FCGR3A and FCGR3B CNV genotypes were compared between 671 biopsy-proven sarcoidosis patients and the same number of healthy controls matched with age, sex, race, and geographic area from the ACCESS (A Case Control Etiologic Study of Sarcoidosis) cohort. Flow cytometry analyses were used to determine expressions of FcγRIIIA on NK cells and FcγRIIIB on neutrophils in phenotype analyses. We found that FCGR3A CNVs were significantly associated with sarcoidosis in females (CN = 1 vs. CN = 2 logistic regression adjusted for sex and race, OR 4.0156, SE = 2.2784, P = 0.0143; CN = 3 vs. CN = 2 logistic regression adjusted for sex and race, OR 2.8044, SE = 1.1065, P = 0.0090), suggesting that FCGR3A gene abnormality influences sarcoidosis development in a gender-specific manner. Furthermore, FcγRIIIA expressions were significantly decreased on NK cells from sarcoidosis patients compared to those from healthy controls (P = 0.0007). Additionally, low FCGR3B CN was associated with sarcoidosis (CN <2 vs. CN = 2 logistic regression adjusted for sex and race, OR 1.5025, SE = 0.2682, P = 0.0226), indicating that the functions of FCGR3B gene may also contribute to the pathogenesis of sarcoidosis. We conclude that FCGR3A CNVs are a major risk factor for female sarcoidosis and FCGR3B CNVs may also affect the development of sarcoidosis.

Anti-TNF therapeutics for the treatment of sarcoidosis

Sarcoidosis is a systemic disease with an incidence of 1 to 40 per 100 000 persons per year. It predominantly affects people in the age of 20 to 40 years old. Disease course varies from mild self-limiting to chronic debilitating and life-threatening disease. Since the cause of sarcoidosis is unknown, curative therapy is not available. Immunosuppressive drugs may, however, control the symptoms of the disease. The hallmark of sarcoidosis is the formation of granulomas that are most commonly found in lungs and lymph nodes. As TNF plays an important role in both formation and maintenance of these granulomas, as well as in the immune response, anti-TNF biologicals such as infliximab and adalimumab are considered a last resort therapeutic option. Clinical effectiveness, however, varies considerably and data showing which patients would benefit most from this expensive therapy are scarce. This review summarizes current knowledge on anti-TNF therapeutics in sarcoidosis, and describes insights on prediction of response, outcome measures and antibody development.

Real-time quantitative reverse transcription-polymerase chain reaction to detect propionibacterial ribosomal RNA in the lymph nodes of Chinese patients with sarcoidosis

The aim of this study was to investigate the diagnostic value of using the copy number of propionibacterial rRNA as a biomarker for sarcoidosis. Ribosomal RNA of Propionibacterium acnes and P. granulosum was measured by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) using formalin-fixed and paraffin-embedded tissue of lymph node biopsy from 65 Chinese patients with sarcoidosis, 45 with tuberculosis and 50 controls with other diseases (23 with non-specific lymphadenitis and 27 with mediastinal lymph node metastasis from lung cancer). The receiver operating characteristic (ROC) curve was analysed to determine an optimal cut-off value for diagnosis, and the diagnostic accuracy of the cut-off value was evaluated in additional tissue samples [24 patients with sarcoidosis and 22 with tuberculosis (TB)]. P. acnes or P. granulosum rRNA was detected in 48 of the 65 sarcoidosis samples but only in four of the 45 TB samples and three of the 50 control samples. Analysis of the ROC curve revealed that an optimal cut-off value of the copy number of propionibacterial rRNA for diagnosis of sarcoidosis was 50·5 copies/ml with a sensitivity and specificity of 73·8 and 92·6%, respectively. Based on the cut-off value, 19 of the 24 additional sarcoidosis samples exhibited positive P. acnes or P. granulosum, whereas only one of the 22 additional TB samples was positive, resulting in a sensitivity and specificity of 79·2 and 95·5%, respectively. These findings suggest that propionibacteria might be associated with sarcoidosis granulomatous inflammation. Detection of propionibacterial rRNA by RT-PCR might possibly distinguish sarcoidosis from TB.

Sarcoidosis: Role of non-tuberculosis mycobacteria and Mycobacterium tuberculosis

Sarcoidosis is a granulomatous inflammatory disease that is induced by unknown antigen(s) in a genetically susceptible host. Although the direct link between Mycobacterium tuberculosis (MTB) infection and sarcoidosis can be excluded on the basis of current knowledge, non-infectious mechanisms may explain the causative role of mycobacterial antigens. Ever since sarcoidosis was first described, its relationship with tuberculosis (TB) has been under-investigated. Whereas some researchers consider sarcoidosis and TB as two examples of the same disease process, others have rejected mycobacteria as playing any causative role in sarcoidosis. Whether they are linked causally or not, clinical evidence makes a differential diagnosis between the two conditions very challenging, particularly in countries with high burden of TB. The present study analyzes the relationship between sarcoidosis and TB and its implications in clinical practice. The coincidence of TB and sarcoidosis and the higher incidence of mycobacterial DNA in biological samples of sarcoid patients have been reported by many authors. In addition, new evidence of a similarity in MTB phenotype in sarcoidosis is provided. Overall, these observations suggest that TB and sarcoidosis may not only share the same etiology, but may even be different aspects of one disease.

Macrophage migration inhibitory factor (MIF) -173 polymorphism is associated with clinical erythema nodosum in Löfgren's syndrome

INTRODUCTION

Macrophage migration inhibitory factor (MIF) has been shown to be a key regulator in innate and adaptive immune responses. A single nucleotide polymorphism in the 5' region of the MIF gene, MIF -173∗G/C, is associated with increased MIF protein production, in vivo and in vitro. Associations have been shown between the minor MIF -173C allele and sarcoidosis patients with erythema nodosum (EN). Löfgren's syndrome is an acute and usually self-remitting phenotype of sarcoidosis. It is defined as having an acute onset with bilateral hilar lymphadenopathy (BHL), fever, erythema nodosum (EN) and/or arthritis. The aim of this study was to investigate whether MIF -173G/C associates with the susceptibility to and the clinical manifestations, i.e. arthritis or EN, of Löfgren's syndrome. A total of 171 patients with Löfgren's syndrome and 313 controls were genotyped for a single nucleotide polymorphism at position -173 of the MIF gene (SNP rs755622), using a PCR and a restriction enzyme technique.

RESULTS

There were no significant differences found in the MIF -173C allele frequencies between patients with Löfgren's syndrome and controls. In patients with Löfgren's syndrome with only EN, a significantly increased frequency of the C minor allele was observed compared to patients with arthritis only (p=0.0095; OR 3.08, CI: 1.28-7.39). Patients with only EN compared to patients with EN and arthritis showed a significantly increased frequency of the minor C allele (p=0.044; OR 1.97, CI: 1.01-3.85). But patients with only arthritis compared to patients with EN and arthritis did not show a significant difference in C allele frequency (p=0.270; OR 0.64, CI: 0.29-1.42).

CONCLUSIONS

The MIF -173C allele is associated with erythema nodosum in Löfgren's syndrome, but not with susceptibility to sarcoidosis. This indicates a role for MIF after antigen presenting to the T cell has taken place and the sarcoid inflammatory response has begun.

Gene expression profiles in granuloma tissue reveal novel diagnostic markers in sarcoidosis

Sarcoidosis is an immune-mediated multisystem disease characterized by the formation of non-caseating granulomas. The pathogenesis of sarcoidosis is unclear, with proposed infectious or environmental antigens triggering an aberrant immune response in susceptible hosts. Multiple pro-inflammatory signaling pathways have been implicated in mediating macrophage activation and granuloma formation in sarcoidosis, including IFN-γ/STAT-1, IL-6/STAT-3, and NF-κB. It is difficult to distinguish sarcoidosis from other granulomatous diseases or assess disease severity and treatment response with histopathology alone. Therefore, development of improved diagnostic tools is imperative. Herein, we describe an efficient and reliable technique to classify granulomatous disease through selected gene expression and identify novel genes and cytokine pathways contributing to the pathogenesis of sarcoidosis. We quantified the expression of twenty selected mRNAs extracted from formalin-fixed paraffin embedded (FFPE) tissue (n = 38) of normal lung, suture granulomas, sarcoid granulomas, and fungal granulomas. Utilizing quantitative real-time RT-PCR we analyzed the expression of several genes, including IL-6, COX-2, MCP-1, IFN-γ, T-bet, IRF-1, Nox2, IL-33, and eotaxin-1 and revealed differential regulation between suture, sarcoidosis, and fungal granulomas. This is the first study demonstrating that quantification of target gene expression in FFPE tissue biopsies is a potentially effective diagnostic and research tool in sarcoidosis.

Annexin A11 gene polymorphism (R230C variant) and sarcoidosis in a Portuguese population

A recent genome-wide association study detected a protective effect for the annexin A11 rs1049550*T allele (R230Cvariant) in susceptibility to sarcoidosis. We evaluated the association between rs1049550 C/T and sarcoidosis susceptibility, distinct disease phenotypes and evolution in a Portuguese population. We performed a case-control study of 208 patients and 197 healthy controls. Samples were genotyped for rs1049550 C/T using real-time polymerase chain reaction. The frequency of the annexin A11 rs1049550*T allele was significantly lower in patients than in controls (33.2 vs 44.9%, P < 0.001). Odds ratio of 0.52 and 0.44 were obtained, respectively for carriers of one (CT) and two (TT) copies normalized to the CC wild-type genotype (P < 0.001). There were no significant differences in patients with and without Löfgren syndrome. A significant increase in the frequency of the T allele was observed in patients with bronchoalveolar lavage (BAL) fluid neutrophilia (P = 0.04). No significant associations were seen for lung function pattern, radiological stages or different forms of disease evolution. Our study confirms that rs1049550*T allele exerts a significant protective effect on sarcoidosis susceptibility. Given the role of annexin A11 in cell division, apoptosis and neutrophil function, this polymorphism may affect key elements of granulomatous and interstitial inflammation in sarcoidosis.

Interferon regulatory factor 5 polymorphisms in sarcoidosis

OBJECTIVE

Interferon regulatory factor 5 (IRF5) gene polymorphisms are associated with susceptibility to autoimmune diseases. The aim of this study is to determine the roles of IRF5 single-nucleotide polymorphisms (SNPs) in sarcoidosis.

METHODS

A total of 175 Japanese patients with biopsy-proven sarcoidosis and 150 sex-matched controls were genotyped for four IRF5 SNPs: rs729302A/C, rs2004640G/T, rs10954213A/G, and rs2280714G/A. The associations of these SNPs with susceptibility to sarcoidosis were examined.

RESULTS

Carriage of rs10954213A and rs2280714A conferred significant risks for sarcoidosis [carriage of rs10954213A: odds ratio (OR) = 1.96, 95% confidence interval (CI) = 1.15-3.33, P = 0.01, corrected P = 0.04; carriage of rs2280714A: OR = 1.97, 95% CI = 1.22-3.16, P = 0.005, corrected P = 0.02]. The haplotype carrying rs10954213A and rs2280714A (haplotype 2) was significantly associated with susceptibility to sarcoidosis (OR = 2.00, 95% CI = 1.24-3.24, P = 0.004, corrected P = 0.01). rs729302 and rs2004640 were not associated with susceptibility to sarcoidosis, whereas carriage of rs2004640G was protective against pulmonary hypertension (OR = 0.017, 95% CI = 0.002-0.15, P < 0.001, corrected P < 0.001).

CONCLUSION

A haplotype carrying two functional SNPs of IRF5, rs10954213A and rs2280714A, was associated with the risk of sarcoidosis in the Japanese population.

BTNL2 gene polymorphism associations with susceptibility and phenotype expression in sarcoidosis

A functional polymorphism within butyrophilin-like 2 (BTNL2) gene has been described as a potential risk factor for sarcoidosis. The association between chronicity and the rs2076530 SNP A allele has also been reported. This study evaluates the BTNL2 rs2076530 G/A allele associations with sarcoidosis susceptibility and disease evolution in a Portuguese cohort of patients. A case-control study of 151 patients and 150 controls was performed. Allele frequencies were compared with Chi-square test in a univariate analysis and with logistic regression in a multivariate analysis. BTNL2 rs206530 A allele frequencies were significantly higher in sarcoidosis with no linkage disequilibrium with HLA-DRB1 alleles, except in the subgroup of patients with Löfgren syndrome where the determinant allele was HLA-DRB1*03. The A allele was also increased in those with isolated thoracic disease, with no differences regarding radiological stages or disease evolution. HLA-DRB1*03, besides the association with Löfgren syndrome was significantly related with disease resolution. Our data confirms the association of BTNL2 rs2076530 A allele with sarcoidosis susceptibility in a Portuguese population. We found independent genetic risk factors in clinically distinct disease phenotypes: BTNL2 rs2076530 A allele in patients without Löfgren syndrome or with isolated thoracic disease, and HLA-DRB1*03 in Löfgren syndrome or disease resolution.

Modeling haplotype-haplotype interactions in case-control genetic association studies

Haplotype analysis has been increasingly used to study the genetic basis of human diseases, but models for characterizing genetic interactions between haplotypes from different chromosomal regions have not been well developed in the current literature. In this article, we describe a statistical model for testing haplotype-haplotype interactions for human diseases with a case-control genetic association design. The model is formulated on a contingency table in which cases and controls are typed for the same set of molecular markers. By integrating well-established quantitative genetic principles, the model is equipped with a capacity to characterize physiologically meaningful epistasis arising from interactions between haplotypes from different chromosomal regions. The model allows the partition of epistasis into different components due to additive × additive, additive × dominance, dominance × additive, and dominance × dominance interactions. We derive the EM algorithm to estimate and test the effects of each of these components on differences in the pattern of genetic variation between cases and controls and, therefore, examine their role in the pathogenesis of human diseases. The method was further extended to investigate gene-environment interactions expressed at the haplotype level. The statistical properties of the models were investigated through simulation studies and its usefulness and utilization validated by analyzing the genetic association of sarcoidosis from a human genetics project.

HLA-DRB1 allele frequencies and C4 copy number variation in Finnish sarcoidosis patients and associations with disease prognosis

Sarcoidosis is a multiorgan immune-mediated disease of unknown etiology with varying clinical pictures. We studied 3 genes in the major histocompatibility complex region (HLA-DRB1 and complement C4A and C4B) in patients with resolved disease after a 2-year follow-up (n = 90) and in patients whose disease was still active at that time point (n = 98) and compared them with controls (n = 150). Our primary aim was to detect genetic differences between the patient groups. We observed that the susceptibility allele for sarcoidosis was HLA-DRB1*15:01 (p = 0.011; odds ratio [OR] = 1.67) and the protective allele was HLA-DRB1*01:01 (p = 0.001; OR = 0.43). HLA-DRB1*03:01 was associated with resolving disease when compared with the persistent group (p = 0.011; OR = 2.22). The probability of having resolving disease was even greater if the patient had HLA-DRB1*03:01 and did not have extrapulmonary lesions (p = 0.001; OR = 3.39). By evaluating amino acid variants of the HLA-DRB1 gene, we determined that specific amino acids in pockets 4, 7, and 9 were associated with the prognosis of sarcoidosis. Our results support the importance of HLA-DRB1 as a predisposing gene for sarcoidosis. Particularly, HLA-DRB1*03:01 and polymorphisms of DRB1 pocket residues were associated with a favorable prognosis. Thus, accurate categorization of disease phenotype and HLA-DRB1 sequencing offer a basis for disease course estimation of sarcoidosis.

Evidence for mycobacteria in sarcoidosis

Despite its recognition as a distinct granulomatous disease for over a century, the etiology of sarcoidosis remains to be defined. Since the early 1900s, infectious agents have been suspected in causing sarcoidosis. For much of this time, mycobacteria were considered a likely culprit, yet until recently, the supporting evidence has been tenuous at best. In this review, we evaluate the reported association between mycobacteria and sarcoidosis. Historically, mycobacterial infection has been investigated using histologic stains, cultures of lesional tissue or blood, and identification of bacterial nucleic acids or bacterial antigens. More recently, advances in biochemical, molecular, and immunological methods have produced a more rigorous analysis of the antigenic drivers of sarcoidosis. The result of these efforts indicates that mycobacterial products likely play a role in at least a subset of sarcoidosis cases. This information, coupled with a better understanding of genetic susceptibility to this complex disease, has therapeutic implications.

CD277 is a negative co-stimulatory molecule universally expressed by ovarian cancer microenvironmental cells

CD277, a member of the butyrophilin subfamily 3 (BTN3), shares significant sequence similarities and predicted common structural features with inhibitory B7-H4 and other members of the B7 superfamily. Here we report that CD277 is consistently expressed in stromal, as well as tumor cells in the microenvironment of human advanced ovarian carcinoma specimens, both of primary and metastatic origin. MHC-II+ myeloid antigenpresenting leukocytes (dendritic cells and macrophages) express significantly higher levels of surface CD277, compared to other tumor-infiltrating leukocyte subsets, and this expression is significantly up-regulated by multiple common tumor microenvironmental signals, including VEGF and CCL3. Most importantly, engagement of CD277 on the surface of TCR-stimulated T cells inhibits their otherwise robust expansion and production of Th1 cytokines by preventing the up-regulation of cFLIP. Our results point to a role for CD277 up-regulated by microenvironmental signals in the acquisition of a regulatory phenotype by tumor-associated myeloid cells. Consequently, CD277, and likely other butyrophilins and butyrophilin-like molecules, emerge as regular players in the orchestration of immunosuppressive networks in ovarian cancer, and therefore new targets for interventions to overcome immune evasion and boost anti-tumor immunity in cancer patients.

Recent advances in sarcoidosis

Sarcoidosis, a systemic granulomatous disease of undetermined etiology, is characterized by a variable clinical presentation and course. During the past decade, advances have been made in the study of sarcoidosis. The multicenter ACCESS (A Case Control Etiologic Study of Sarcoidosis) trial recruited > 700 subjects with newly diagnosed sarcoidosis and matched control subjects. Investigators were unable to identify a single cause of sarcoidosis, but ACCESS paved the way for subsequent etiologic studies. The Mycobacterium tuberculosis catalase-peroxidase protein has been identified as a potential sarcoidosis antigen. Genetic aspects of the disease have been elucidated further. Genome-wide scans have identified candidate genes. Gene expression analyses have defined cytokine dysregulation in sarcoidosis more clearly. Although the criteria for diagnosis have not changed, sarcoidosis remains a diagnosis of exclusion best supported by a tissue biopsy specimen that demonstrates noncaseating granulomas in a patient with compatible clinical and radiologic features of the disease. Endobronchial ultrasound-guided transbronchial needle aspiration of mediastinal lymph nodes has facilitated diagnosis, often eliminating the need for more invasive procedures, such as mediastinoscopy. PET scanning has proven valuable in locating occult sites of active disease. Currently, no reliable prognostic biomarkers have been identified. The tumor necrosis factor inhibitors, a relatively new class of agents, have been used in patients with refractory disease. It is unclear whether phosphodiesterase-5 inhibitors, prostaglandin analogs, or endothelin antagonists should be used for the treatment of sarcoidosis-associated pulmonary hypertension.

Butyrophilin-like 2 in pulmonary sarcoidosis: a factor for susceptibility and progression?

The aims of this study were to assess the association of BTNL2G16071A with the course of pulmonary sarcoidosis and to verify the association with disease predisposition. In addition, the linkage between BTNL2G16071A and certain human leukocyte antigen (HLA)-DRB1/DQB1 types was investigated. In a retrospective case-control study BTNL2G16071A, HLA-DQB1, and HLA-DRB1 were typed in 632 sarcoidosis patients. These patients were classified into 304 patients with persistent sarcoidosis and 328 patients with nonpersistent sarcoidosis. The BTNL2 16071A variant allele was present significantly more often in patients with persistent disease (92.4%; 281/304) compared with patients demonstrating a nonpersistent course (86.6%; 284/328; odds ratio (OR) = 1.89 with 95% confidence interval (95% CI) 1.11-3.22). Furthermore, BTNL2 16071A variant allele carriers have an increased risk (OR = 1.85, 95% CI 1.19-2.88) of developing sarcoidosis. Moreover, the strong linkage between variant allele and HLA-DRB1*15 presence (OR = 8.43, 95% CI 3.02-23.5) was confirmed. The presence of a BTNL2G16071A variant allele almost doubles the risk of progressing to persistent pulmonary sarcoidosis in addition to increasing the risk of developing sarcoidosis. Presumably, these increased risks are caused by the strong linkage between BTNL2G16071A and DRB1*15. The choice between determining BTNL2G16071A SNP or the HLA-DRB1 type depends on the ability and/or availability to perform either test.

Major histocompatibility complex class II transactivator gene polymorphism: associations with Löfgren's syndrome

The major histocompatibility complex (MHC) class II transactivator (MHC2TA) is known as a master regulator for expression of MHC class II molecules. In the present study, we investigated the influence on the risk for sarcoidosis of two variants of the MHC2TA gene, selected from previous association studies of inflammatory diseases. Seven hundred and twenty-eight sarcoidosis patients and 873 controls matched by ethnicity were included in the study. Patients were classified as with Löfgren's syndrome (or not) as subphenotypes. Individuals were genotyped for two single nucleotide polymorphisms (SNPs) of the MHC2TA gene, rs3087456 A/G and rs11074932 C/T, and were human leukocyte antigen (HLA)-DRB1-typed. After correction for multiple testing, our data showed a significant association with Löfgren's syndrome in allelic model for the rs3087456 SNP, which was not detected in non-Löfgren's patients. A similar trend was noted for the rs11074932 SNP. These risk factors were independent of HLA-DRB1*03, which is known to be associated with Löfgren's syndrome. The finding of a new genetic association between Löfgren's syndrome and MHC2TA gene polymorphisms, which seems independent of HLA-DRB1*03 and relates to the expression of MHC class II molecules, strongly supports the idea that Löfgren's syndrome is a separate disease entity.

Variation in IL7R predisposes to sarcoid inflammation

Sarcoidosis is a chronic granulomatous disorder characterized by a massive influx of Th1 lymphocytes. Both naive and memory T cells express high levels of interleukin 7 receptor-alpha (IL7R alpha), encoded by the IL7R gene. The purpose of this study was to investigate the role of the IL7R gene region in susceptibility to sarcoidosis. Six common single-nucleotide polymorphisms (SNPs) spanning IL7R were genotyped and analyzed in 475 sarcoidosis patients and 465 healthy controls. Replication of one significant associated SNP was carried out in 206 independent sarcoidosis patients, 127 controls and 126 patients with Löfgren's disease. The rs10213865 SNP was associated with sarcoidosis (P=0.008), and in silico analysis showed a complete linkage (r(2)=1, D'=1) with a functional nonsynonymous coding SNP in exon 6 (rs6897932, T244I). Combined analysis of 663 individuals with sarcoidosis and 586 controls (homozygous carriers of risk allele, P=5 x 10(-4), odds ratio=1.49 (1.19-1.86)) provided strong statistical support for a genuine association of IL7R with the risk of sarcoidosis. In addition, we report the same trend between variation in the IL7R gene and patients with Löfgren's disease, suggesting that variation in IL7R may confer general risk for developing granulomatous lung disease.

Neurosarcoidosis with necrotising sarcoid granulomatosis mimicking meningiomatosis cerebri: case report and literature search

A 52-year-old woman presented with headaches, difficulty with word finding and left eye blindness. MRI showed enhancing frontal dural-based masses suggestive of meningiomatosis. Biopsy and debulking revealed necrotising granulomas, without discernible micro-organisms or neoplasia; a thorough clinical work-up was negative for infection and vasculitis. A CT scan showed mild bilateral hilar lymphadenopathy, a tiny pulmonary nodule and cirrhotic liver. Her subsequent alteration of mental status was attributed to hepatic encephalopathy based upon elevated aminotransferase and ammonia levels, biopsy evidence of hepatoportal sclerosis with rare granulomas and response to lactulose. A diagnosis of neurosarcoidosis of the necrotising sarcoid granulomatosis variant (NS-NSG) with atypical systemic involvement was made. This is the fifth case report of NS-NSG clinically mimicking a neoplasm and histologically mimicking a mycobacterial infection. NS-NSG can have an atypical clinical picture including intracranial masses; a thorough work-up to exclude infectious and other non-infectious aetiologies is a prerequisite to its diagnosis.