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Rationale: Sarcoidosis is a multisystem disease of unknown cause. Löfgren's syndrome (LS) is a characteristic subgroup of sarcoidosis that is associated with a good prognosis in sarcoidosis. However, little is known about its genetic architecture or its broader phenotype, non-LS sarcoidosis., Objectives: To address the genetic architecture of sarcoidosis phenotypes, LS and non-LS., Methods: An association study in a white Swedish cohort of 384 LS, 664 non-LS, and 2,086 control subjects, totaling 3,134 subjects using a fine-mapping genotyping platform was conducted. Replication was performed in four independent cohorts, three of white European descent (Germany, n = 4,975; the Netherlands, n = 613; and Czech Republic, n = 521), and one of black African descent (United States, n = 1,657), totaling 7,766 subjects., Measurements and Main Results: A total of 727 LS-associated variants expanding throughout the extended major histocompatibility complex (MHC) region and 68 non-LS-associated variants located in the MHC class II region were identified and confirmed. A shared overlap between LS and non-LS defined by 17 variants located in the MHC class II region was found. Outside the MHC region, two LS-associated loci, in ADCY3 and between CSMD1 and MCPH1, were observed and replicated., Conclusions: Comprehensive and integrative analyses of genetics, transcription, and pathway modeling on LS and non-LS indicates that these sarcoidosis phenotypes have different genetic susceptibility, genomic distributions, and cellular activities, suggesting distinct molecular mechanisms in pathways related to immune response with a common region.

Rationale: Genetic variation plays a significant role in the etiology of sarcoidosis. However, only a small fraction of its heritability has been explained so far., Objectives: To define further genetic risk loci for sarcoidosis, we used the Immunochip for a candidate gene association study of immune-associated loci., Methods: Altogether the study population comprised over 19,000 individuals. In a two-stage design, 1,726 German sarcoidosis cases and 5,482 control subjects were genotyped for 128,705 single-nucleotide polymorphisms using the Illumina Immunochip for the screening step. The remaining 3,955 cases, 7,514 control subjects, and 684 parents of affected offspring were used for validation and replication of 44 candidate and two established risk single-nucleotide polymorphisms., Measurements and Main Results: Four novel susceptibility loci were identified with genome-wide significance in the European case-control populations, located on chromosomes 12q24.12 (rs653178; ATXN2/SH2B3), 5q33.3 (rs4921492; IL12B), 4q24 (rs223498; MANBA/NFKB1), and 2q33.2 (rs6748088; FAM117B). We further defined three independent association signals in the HLA region with genome-wide significance, peaking in the BTNL2 promoter region (rs5007259), at HLA-B (rs4143332/HLA-B*0801) and at HLA-DPB1 (rs9277542), and found another novel independent signal near IL23R (rs12069782) on chromosome 1p31.3., Conclusions: Functional predictions and protein network analyses suggest a prominent role of the drug-targetable IL23/Th17 signaling pathway in the genetic etiology of sarcoidosis. Our findings reveal a substantial genetic overlap of sarcoidosis with diverse immune-mediated inflammatory disorders, which could be of relevance for the clinical application of modern therapeutics.

Rationale: Sarcoidosis is a complex inflammatory disease with a heterogeneous clinical picture. Among others, an acute and chronic clinical course can be distinguished, for which specific genetic risk factors are known., Objectives: To identify additional risk loci for sarcoidosis and its acute and chronic subforms, we analyzed imputed data from a genome-wide association scan for these phenotypes., Methods: After quality control, the genome-wide association scan comprised nearly 1.3 million imputed single-nucleotide polymorphisms based on an Affymetrix 6.0 Gene Chip dataset of 564 German sarcoidosis cases, including 176 acute and 354 chronic cases and 1,575 control subjects., Measurements and Main Results: We identified chromosome 11q13.1 (rs479777) as a novel locus influencing susceptibility to sarcoidosis with genome-wide significance. The marker was significantly associated in three distinct German case-control populations and in an additional German family sample with odds ratios ranging from 0.67 to 0.77. This finding was further replicated in two independent European case-control populations from the Czech Republic (odds ratio, 0.75) and from Sweden (odds ratio, 0.79). In a meta-analysis of the included European case-control samples the marker yielded a P value of 2.68 × 10(-18). The locus was previously reported to be associated with Crohn disease, psoriasis, alopecia areata, and leprosy. For sarcoidosis, fine-mapping and expression analysis suggest KCNK4, PRDX5, PCLB3, and most promising CCDC88B as candidates for the underlying risk gene in the associated region., Conclusions: This study provides striking evidence for association of chromosome 11q13.1 with sarcoidosis in Europeans, and thus identified a further genetic risk locus shared by sarcoidosis, Crohn disease and psoriasis.

Background: Pulmonary sarcoidosis is a multisystem granulomatous disease with various clinical phenotypes. So far, there has been little information on protein patterns (PPs) of bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis and no data are available on PPs in clinical disease subtypes., Objectives: To investigate the PP of BALF from patients with pulmonary sarcoidosis, to evaluate whether PPs reflect disease course as assessed by chest X-ray (CXR), and to compare PPs between patients with/without Löfgren's syndrome., Methods: Surface-enhanced laser desorption/ionization-time-of-flight mass spectroscopy was applied to investigate PPs in unconcentrated BALF from 65 patients (CXR stage I, n = 32; CXR stage II, n = 22, CXR stage III, n = 11) and 23 healthy control subjects. The Mann-Whitney U test was used to detect differentially expressed protein peaks. After reversed-phase fractionation, peptide fingerprint mapping and immunodepletion were used to identify deregulated (up-regulated or down-regulated) proteins., Results: Forty differentially expressed protein entities (2.75-185.62 kD) were detected in patients with pulmonary sarcoidosis versus control subjects (p < 0.05). Whereas 13 peaks (33%) were present across all CXR stages, 27 (67%) were specific for particular CXR stages. Comparison of PPs between CXR stage I patients with or without Löfgren's syndrome revealed 25 differentially expressed peaks. The total number of deregulated peaks and also of those associated with sarcoidosis as a whole were markedly lower in patients with Löfgren's syndrome in comparison with other sarcoid phenotypes. Human serum albumin, alpha1-antitrypsin, and protocadherin-2 precursor were identified from sarcoidosis-associated PP., Conclusion: Surface-enhanced laser desorption/ionization-time-of-flight mass spectroscopy enables determination of protein patterns in sarcoid BALF and allows detection of protein patterns linked to a particular disease course.

In this study, messenger RNA (mRNA) expression for novel T lymphocyte chemoattractants, leukotactin-1, macrophage inflammatory protein (MIP)-3 alpha and MIP-3 beta was investigated in bronchoalveolar lavage fluid (BALF) cells from patients with sarcoidosis, a T cell-mediated disease with typical CD4+ lymphocyte alveolitis. Of these three chemokines, only MIP-3 beta mRNA was upregulated in sarcoidosis, and therefore, protein levels of this chemokine, its pharmacologic regulation, and association with disease clinical course were explored. MIP-3 beta protein concentrations were elevated in BALF from sarcoid patients compared with control subjects (p = 0.001) and in patients with chest X-ray stage II chemokine protein levels were increased compared with stage I (p = 0.003). MIP-3 beta protein was associated predominantly with alveolar macrophages and correlated with BALF lymphocytes and T cell subsets. mRNA expression for the MIP-3 beta receptor, CC chemokine receptor 7, was increased in sarcoidosis and correlated with MIP-3 beta protein levels. MIP-3 beta mRNA and protein expression in BALF cells was suppressed by dexamethasone and cyclosporine A in vitro. In conclusion, MIP-3 beta is implicated in T lymphocyte recruitment in sarcoidosis, is associated with disease progression, and is downregulated by drugs used for sarcoidosis treatment. This novel chemokine, therefore, represents a candidate for studies of sarcoidosis pathobiologic mechanisms.

Members of the interleukin-1 (IL-1) family are implicated in the pathogenesis of sarcoidosis and idiopathic pulmonary fibrosis (IPF). We have, therefore, performed a case-control study to investigate a plausible association between sarcoidosis and the polymorphisms in the IL-1alpha, IL-1beta, and IL-1 receptor antagonist (IL-1Ra) genes. Further, as a separate question, we explored whether the aforementioned genes of the IL-1 cluster are associated with IPF. Using PCR with sequence-specific primers, IL-1alpha -889, IL-1beta -511, IL-1beta +3953, and IL-1Ra intron 2 VNTR polymorphisms were determined in 348 white subjects of West Slavonic ancestry (95 patients with sarcoidosis, 54 patients with IPF, and 199 healthy control subjects). The IL-1alpha -889 1.1 genotype was significantly overrepresented in patients with sarcoidosis in comparison with control subjects (60.0 versus 44.2%, p = 0.012, p(corr) = 0.047). The distribution of IL-1beta -511, IL-1beta +3953, and IL-1Ra VNTR genotypes and alleles did not significantly differ between the cases and controls. No association between IPF and the investigated polymorphisms was found. Strong linkage disequilibrium between pairs of polymorphic loci was observed. Further population studies are warranted to confirm the observed association between sarcoidosis and the IL-1alpha polymorphism and also to explore mechanisms of IL-1alpha -889 participation in aberrant immune response in sarcoidosis.

Previous studies of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene in sarcoidosis have revealed both ethnic heterogeneity of I/D frequencies and controversy surrounding the association between the polymorphism and severity of disease. The objective of this study was, therefore, to clarify the role of the ACE I/D polymorphism in (1) disease susceptibility, (2) pulmonary disease severity (with particular reference to pulmonary fibrosis), and (3) pulmonary disease progression, in two distinct European sarcoidosis populations. Standard chest radiographic staging was performed on 118 UK and 56 Czech white patients with sarcoidosis at 2 yr from presentation. Pulmonary function data were analyzed, and patients were then categorized according to disease severity. A PCR-SSP assay was used to determine the ACE I/D genotype of each patient studied. The I/D allele frequencies from these patients were compared with frequencies from ethnically matched UK (n = 386) and Czech (n = 179) control subjects using a chi-square contingency table. No significant differences were seen in the distribution of the ACE I/D genotypes, allele frequencies or phenotype frequencies. Furthermore, no association was found between the ACE I/D polymorphism and pulmonary disease severity, fibrosis, and progression. We conclude that the ACE I/D polymorphism has no role in sarcoidosis susceptibility in European whites and that it is not a regulatory variant in this disease.

Genes for the chemokine receptors CCR5 and CCR2 are characterized by polymorphisms resulting in a nonfunctional receptor expression. Ligands for CCR2 and CCR5 (chemokines monocyte chemotactic protein-1 [MCP-1] and RANTES) are implicated in the pathogenesis of sarcoidosis. We have, therefore, analyzed polymorphisms of CCR5 (32-bp deletion in CCR5 gene [Delta32]) and of CCR2 (replacement of valine by isoleucine in CCR2 gene [64I]) in 66 Czech patients with sarcoidosis in comparison with a representative sample of Czech normal population. The frequencies of CCR5Delta32 and CCR2-64I polymorphisms in patients with sarcoidosis were different from that in control subjects. CCR5Delta32 allelic frequency was significantly increased in patients. By contrast, the CCR2-64I allele was more frequent in control subjects; however, the difference did not attain significance. Interestingly, the CCR5Delta32 allele was associated with clinically more apparent disease: it was present in 39.1% of patients requiring corticosteroids but only in 16.7% patients who did not need therapeutic intervention (odds ratio [OR] = 2.9). When patients requiring corticosteroids were compared with control subjects, the differences in the CCR5Delta32 frequencies were enhanced (p < 0.01). In conclusion, the observed association of CCR5Delta32 and CCR2-64I with sarcoidosis implicates a role for these polymorphisms in disease susceptibility and protection.