Characterization of the PF-ILD phenotype in patients with advanced pulmonary sarcoidosis.

BACKGROUND: Advanced pulmonary sarcoidosis causes significant morbidity and can lead to death. Large trials demonstrated efficacy of antifibrotics in patients with progressive fibrosing interstitial lung diseases (PF-ILD), including a few with sarcoidosis. To date, little is known about this progressive fibrosing phenotype in sarcoidosis. Diffusion capacity of carbon monoxide (DLCO) may be a useful functional marker to screen for advanced pulmonary sarcoidosis. In this study, we describe a cohort with advanced pulmonary sarcoidosis and we gain insights in the progressive fibrosing phenotype in sarcoidosis. METHODS: Patients with sarcoidosis and a DLCO < 50% predicted were included in this retrospective cohort study. First measurement of DLCO < 50% predicted was the baseline. Lung function data, HRCT, pulmonary hypertension (PH) and mortality were collected. Patients with > 10% fibrosis on HRCT meeting the criteria for ILD-progression within 24 months were labelled as PF-ILD. With Cox-regression analysis predictors of mortality were established. RESULTS: 106 patients with a DLCO < 50% predicted were included. Evolution of forced vital capacity (FVC) varied widely between patients from - 34% to + 45% after 2 years follow-up, whereas change in DLCO varied between - 11% and + 26%. Fourteen patients (15%) met the PF-ILD criteria, of whom 6 (43%) died within 10 years versus 10 (13%) in the non PF-ILD group (p = 0.006). PH was present 12 (11%), 56 (53%) demonstrated > 10% fibrosis on HRCT. Independent predictors of mortality and lung transplantation in the whole cohort are PH, PF-ILD and UIP-like pattern. CONCLUSION: In conclusion, within this group with advanced pulmonary sarcoidosis disease course varied widely from great functional improvement to death. PF-ILD patients had higher mortality rate than the mortality in the overall pulmonary sarcoidosis group. Future research should focus on the addition of antifibrotics in these patients. Trial registration retrospectively registered.

Simultaneous testing of immunological sensitization to multiple antigens in sarcoidosis reveals an association with inorganic antigens specifically related to a fibrotic phenotype.

Organic and inorganic antigens were studied simultaneously in the same cohort of sarcoidosis patients to investigate whether correlations between clinical characteristics and immunological sensitization could reveal new phenotypes. Sensitization to antigens of mycobacteria, Propionibacterium acnes catalase and vimentin was investigated in 201 sarcoidosis and 51 obstructive sleep apnoea patients, serving as control group. Sensitization to aluminium, beryllium, silica and zirconium was also studied in 105 of the sarcoidosis patients and in 24 of the controls. A significantly higher percentage of sarcoidosis patients (27·6%) than controls (4·2%) had an immunological response to metals or silica (P = 0·014). A higher percentage of these sarcoidosis patients showed fibrosis on chest X-ray 5 years after the diagnosis (69·2 versus 30·3%, P = 0·016). No significant differences in mycobacterial or vimentin enzyme-linked immunospot (ELISPOT) assay results were observed between sarcoidosis and control patients. A significantly lower percentage of sarcoidosis patients (3·5%) than control patients (15·7%) had a positive ELISPOT for P. acnes catalase (P = 0·003). However, sarcoidosis patients sensitized to P. acnes catalase were more likely to have skin involvement, while sarcoidosis patients sensitized to mycobacterial antigens were more likely to have cardiac involvement. Our study suggests a more prominent role for inorganic triggers in sarcoidosis pathogenesis than previously thought. Immunological sensitization to inorganic antigens was associated with development of fibrotic sarcoidosis. No association was found between sensitization to bacterial antigens or vimentin and sarcoidosis in Dutch patients. However, our data suggest that trigger-related phenotypes can exist in the heterogeneous population of sarcoidosis patients.

Immunoreactivity to metal and silica associates with sarcoidosis in Dutch patients.

BACKGROUND: Involvement of metals or silica in the pathogenesis of sarcoidosis has been suggested by several case reports and specific epidemiological studies. However, the combination of occupational exposure and an immunological reaction has not been studied before in a group of sarcoidosis patients and non-sarcoidosis controls. METHODS: In 256 sarcoidosis patients and 73 control patients with obstructive sleep apnea, exposure to metal and silica was assessed using a questionnaire consisting of a complete occupational history subsequently linked to job-exposure matrices. Next, immunoreactivity to aluminium, beryllium, zirconium and silica was determined in 33 sarcoidosis and 19 control patients using a lymphocyte proliferation test. RESULTS: In sarcoidosis, 83 out 256 patients (32.4%) had occupational exposure to metals or silica, compared to 24.7% in the control group (p = 0.21). A significantly higher percentage of the sarcoidosis patients tested showed immunoreactivity to metals or silica compared to the control group (21.2 and 0% respectively, p = 0.039). CONCLUSIONS: Immunoreactivity to silica and metals was only found in sarcoidosis patients, supporting the hypothesis that these antigens may be involved in the pathogenesis of a distinct subgroup of sarcoidosis patients. This indicates that when searching for causative agents in sarcoidosis patients, besides beryllium, also zirconium, aluminium and silica deserve clinical investigation.

Genetic variation in the Toll-like receptor gene cluster (TLR10-TLR1-TLR6) influences disease course in sarcoidosis.

Sarcoidosis is an inflammatory disease of unknown etiology. Various microorganisms have been proposed as etiologic agent suggesting a role for pattern-recognition receptors such as Toll-like receptors (TLRs) in disease pathogenesis, with a special interest in TLR-2. TLR-10, TLR-1, and TLR-6 act as co-receptors for TLR-2 and the genes encoding these receptors are located in a gene cluster on chromosome 4. The aim of our study was to assess differences in genetic variation in the TLR10-TLR1-TLR6 gene cluster between patients and controls. A total of eight single nucleotide polymorphisms were genotyped in 447 healthy controls and 533 patients, divided in 425 with sarcoidosis and 108 with Löfgren's syndrome. Comparison of the total patient cohort with controls showed that the allele frequencies of rs1109695, rs7658893 (TLR-10), and rs5743604 as well as rs5743594 (TLR-1) differed significantly. Haplotype analysis showed that the most common haplotype found was significantly decreased in patients with chronic sarcoidosis. Furthermore, a less common haplotype was found to be significantly increased in patients with Löfgren's syndrome as well as sarcoidosis patients with self-remitting disease, indicating that it could act as a disease modifying haplotype. In conclusion, our study suggests that absence of the common haplotype in the TLR10-TLR1-TLR6 gene cluster increases the risk of developing chronic disease in patients already affected by sarcoidosis. Based on their role as co-receptors for TLR-2, this study supports the growing evidence that aberrant TLR-2 function is important in sarcoidosis disease pathogenesis.

The usefulness of repeated CMR and FDG PET/CT in the diagnosis of patients with initial possible cardiac sarcoidosis.

BACKGROUND: Cardiac sarcoidosis (CS) diagnosis is usually based on advanced imaging techniques and multidisciplinary evaluation. Diagnosis is classified as definite, probable, possible or unlikely. If diagnostic confidence remains uncertain, cardiac imaging can be repeated. The objective is to evaluate the usefulness of repeated cardiac magnetic resonance imaging (CMR) and fluorodeoxyglucose positron emission tomography (FDG PET/CT) for CS diagnosis in patients with an initial "possible" CS diagnosis. METHODS: We performed a retrospective cohort study in 35 patients diagnosed with possible CS by our multidisciplinary team (MDT), who received repeated CMR and FDG PET/CT within 12 months after diagnosis. Imaging modalities were scored on abnormalities suggestive for CS and classified as CMR+/PET+, CMR+/PET-, CMR-/PET+ and CMR-/PET-. Primary endpoint was final MDT diagnosis of CS. RESULTS: After re-evaluation, nine patients (25.7%) were reclassified as probable CS and 16 patients (45.7%) as unlikely CS. Two patients started immunosuppressive treatment after re-evaluation. At baseline, eleven patients (31.4%) showed late gadolinium enhancement (LGE) on CMR (CMR+) and 26 (74.3%) patients showed myocardial FDG-uptake (PET+). At re-evaluation, nine patients (25.7%) showed LGE (CMR+), while 16 patients (45.7%) showed myocardial FDG-uptake (PET+). When considering both imaging modalities together, 82.6% of patients with CMR-/PET+ at baseline were reclassified as possible or unlikely CS, while 36.4% of patients with CMR+ at baseline were reclassified as probable CS. Three patients with initial CMR-/PET+ showed LGE at re-evaluation. CONCLUSION: Repeated CMR and FDG PET/CT may be useful in establishing or rejecting CS diagnosis, when initial diagnosis is uncertain. However, clinical relevance has to be further determined.

Effectiveness and safety of infliximab in cardiac Sarcoidosis.

BACKGROUND: Immunosuppressive therapy in active cardiac sarcoidosis (CS) might prevent potential life-threatening complications. Infliximab (IFX) is a tumor necrosis factor alpha monoclonal antibody proven to be effective in refractory extracardiac sarcoidosis. It is sparsely used in CS, because of its association with worsening heart failure in prior studies. The goal of this study is to assess the effectiveness and safety of IFX in CS. METHODS AND RESULTS: A retrospective, single center cohort study was performed in sarcoidosis patients treated with IFX based on a cardiac indication between January 2016 and March 2019. Patients received IFX intravenously at a dose of 5 mg/kg at week 0, 2, and subsequently every 4 weeks. After every six months, treatment response was evaluated within the multidisciplinary team using FDG-PET/CT, transthoracic echocardiography, biomarkers and device interrogation reports. Responder analysis definitions were based on; dosage of immunosuppressive drugs, improvement in functional class, left ventricular ejection fraction (LVEF) and SUVmax. Twenty-two patients were included (mean age 51.0 SD10.0 years, male 68.2%) with a mean follow-up of 18.9 months (6 to 44 months) of whom 18 (82%) were classified as responders. Median SUVmax on FDG-PET/CT decreased from SUVmax 5.2 [3.7-8.4] to 2.3 [1.4-2.3], p = 0.015. The target-to-background ratio decreased from 3.2 [2.1-5.1] to 1.0 [0.7-2.4], p = 0.002. The median left ventricular (LV) ejection fraction increased from 45.0% [34.0-60.0] to 55.0% [41.0-60.0], p = 0.02. The majority of patients (73%) experienced no side effects and no patients had worsening of heart failure. CONCLUSION: In this pilot study, patients with refractory CS treated with infliximab, on top of standard of care, had a reduction in inflammation on FDG-PET/CT and an improvement in LV function, without serious adverse events.

Toll-like receptor (TLR)-9 genetics and function in sarcoidosis.

Sarcoidosis is a systemic disorder characterized by the formation of non-caseating granulomas in variable organs. Toll-like receptor (TLR)-9 is important in the innate immune response against both Mycobacterium tuberculosis and Propionibacterium acnes, candidate causative agents in sarcoidosis. The aim of our study was to investigate possible genetic and functional differences in TLR-9 between patients and controls. TLR-9 single nucleotide polymorphisms were genotyped in 533 patients and divided into a study cohort and validation cohort and 185 healthy controls. Furthermore, part of the promotor as well as the entire coding region of the TLR-9 gene were sequenced in 20 patients in order to detect new mutations. No genetic differences were found between patients and controls. In order to test TLR-9 function, peripheral blood mononuclear cells (PBMCs) of 12 healthy controls and 12 sarcoidosis patients were stimulated with a TLR-9 agonist and the induction of interleukin (IL)-6, interferon (IFN)-γ and IL-23 was measured. Sarcoidosis patients produce significantly less IFN-γ upon stimulation with different stimuli. Regarding IL-23 production, a significant difference between patients and controls was found only after stimulation with the TLR-9 agonist. In conclusion, we did not find genetic differences in the TLR-9 gene between sarcoidosis patients and controls. Sarcoidosis patients produce less IFN-γ regardless of the stimulating agent, probably reflecting the anergic state often seen in their peripheral blood T lymphocytes. The differences in TLR-9-induced IL-23 production could indicate that functional defects in the TLR-9 pathway of sarcoidosis patients play a role in disease susceptibility or evolution.

Value of serum soluble interleukin-2 receptor as a diagnostic and predictive biomarker in sarcoidosis.

BACKGROUND: Differentiating between interstitial lung diseases (ILD) is challenging. Serum soluble interleukin 2 receptor (sIL-2R) is used as a diagnostic marker in sarcoidosis, but its diagnostic value has not yet been studied in other ILDs like Idiopathic Pulmonary Fibrosis (IPF) or Hypersensitivity Pneumonitis (HP). Also, the prognostic value of sIL-2R in sarcoidosis remains unknown. METHODS: This retrospective cohort study included 121 patients with sarcoidosis, 35 with cHP, 62 with IPF (idiopathic pulmonary fibrosis) and 70 healthy controls. Serum sIL-2R levels were determined at diagnosis. Follow-up data were available for patients with chronic sarcoidosis (n = 64) and patients with non-chronic sarcoidosis (n = 29). RESULTS: Patients with sarcoidosis had higher sIL-2R levels (median 5418 pg/mL) than patients with cHP (median 4015 pg/mL, P = 0.002) and IPF (median 4192 pg/mL, P = 0.034). No differences were found between patients with cHP and IPF. Logistic regression revealed that sIL-2R at diagnosis is a significant predictor of the development of chronic sarcoidosis (OR = 2.1, P = 0.032). CONCLUSION: High levels of sIL-2R are suggestive of sarcoidosis, although a broad overlap exists in sIL-2R levels across sarcoidosis, cHP, and IPF. High levels of sIL-2R might serve as a prognostic biomarker for chronicity.

[A man with dyspnoea after a kidney transplant]. / Een man met kortademigheid na niertransplantatie.

We present a 62-year-old man with a kidney transplant in the past. Because of progressive dyspnoea a CT-scan was made, which showed ground glass in the upper fields with calcifications. He was diagnosed with metastatic pulmonary calcification, which is mostly seen in patient with renal failure and secondary hyperparathyroidism.

Clubbing in patients with fibrotic interstitial lung diseases.

BACKGROUND: Clubbing is associated with poor prognosis and is variably present in patients with idiopathic pulmonary fibrosis (IPF), but is also seen in other fibrotic interstitial lung diseases (ILDs). Little is known about the best methodology to assess clubbing in ILDs and, hence, the prevalence and clinical utility and clinical significance of clubbing. We therefore aimed to evaluate the agreement between different clubbing assessment methods in patients with fibrotic ILDs. Additionally, we assessed the prevalence of clubbing in different fibrotic ILDs and related clubbing to disease severity and quality of life. METHODS: Consecutive outpatients with fibrotic ILDs of two tertiary referral centers were included. Clubbing was assessed with the phalangeal depth ratio, the digital index, the Schamroth sign test, and by the treating physicians and investigator. RESULTS: We included 153 patients (100 men), mean age 65 (range 33-88), mean FVC 79% (25-145%), mean TLCOc 50% (16-104%). Different methods for assessment of clubbing had poor correlation, and as a result, clubbing prevalence varied according to the method used, ranging from 7 to 42% in the total group of patients and 7-52% in IPF. The degree of clubbing did not correlate with FVC or TLCOc (p > 0.2) or with quality of life scores, but lower mean TLCOc scores were seen in patients with clubbing than in those without. CONCLUSION: Clubbing was present in 7-42% of our fibrotic ILD cohort and showed no correlation with disease severity. Although considered an important clinical feature, assessment methods for clubbing showed no to poor agreement. Further studies are therefore needed to gain more insight into measuring clubbing reliably and the possible prognostic value and evolution of clubbing.

Linkage between Toll-like receptor (TLR) 2 promotor and intron polymorphisms: functional effects and relevance to sarcoidosis.

The intracellular pathogens Propionibacterium acnes and Mycobacterium tuberculosis have been leading suspects as the cause of sarcoidosis, a systemic disorder characterized by the formation of non-caseating granulomas. Toll-like receptor (TLR) 2 is important in the innate immune response against both pathogens, and is therefore of interest in sarcoidosis research. In the present study, three single nucleotide polymorphisms and one dinucleotide repeat polymorphism in the TLR-2 gene were genotyped in 419 sarcoidosis patients, divided into a study cohort and a validation cohort, and 196 healthy controls. In the study cohort we found a significant increase in prevalence of the AA-genotype at promotor location -16934 in patients with chronic disease compared to patients with acute/self-remitting sarcoidosis (34.5% versus 15.9%, respectively, P = 0.006, P(c) = 0.019). These results could not be confirmed in our validation cohort, implicating a possible role for TLR-2 genetics in only a small percentage of sarcoidosis patients. Furthermore, linkage was found between the promotor polymorphism -16934 A/T and the number of GT repeats in intron 1 (P < 0.0001). After in vitro stimulation of peripheral blood mononuclear cells (PMBCs) with different TLR-2 agonists, a correlation between induction of TNF-alpha (P = 0.008), interleukin (IL)-12 (P = 0.008) as well as IL-6 (P = 0.02), and the number of GT repeats was observed. In conclusion, the data show that polymorphisms in TLR-2 might be important in a small group of sarcoidosis patients and that their functional consequences explain partly some of the variance in cytokine pattern observed in different clinical phenotypes of this disease.

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.

HLA class I expression and chromosomal deletions at 6p and 15q in head and neck squamous cell carcinomas.

Loss at the chromosomal region 6p21.3 is a frequent event in head and neck squamous cell carcinomas (HNSCC). Since the human leukocyte antigen (HLA) complex is located at 6p21.3, loss of heterozygosity (LOH) of this region may provide tumour cells with an immune-escape tumour phenotype. In the present study, we have studied the correlation of HLA class I, TAP1 and TAP2 expression and LOH at 6p21.3. HLA class I and TAP1 and TAP2 protein expression was analysed by immunohistochemical procedures. A panel of 41 HNSCC with downregulated HLA class I expression was selected for LOH studies using 5 microsatellite markers located at 6p21.3 (D6S105, D6S265, D6S276, D6S273, D6S291) and 2 markers located at the chromosome 6 centromere (D6S473) and the 6p telomere (D6S277). In addition, LOH of the beta-2-nmicroglobulin (beta2m) gene was studied using 2 microsatellite markers flanking the beta2m gene (D15S126 and D15S153) and was correlated with beta2m and HLA class I expression. In 20/41 (49%) of the HNSCC, allelic loss for at least one locus at 6p21.3 was found. Loss at 15q was found in 4/10 (40%) HNSCC with downregulated beta2m expression and in 12/41 (29%) HNSCC with downregulated HLA class I expression. Our data show that downregulation of HLA class I expression is correlated with loss of chromosomal regions at 6p21.3 in HNSCC. In addition, LOH at 6p21.3 and 15q in 10 paired samples of DNA derived from the primary HNSCC, the lymph node metastases and from peripheral blood lymphocytes (PBLs) was studied. Five (5/10) primary tumours contained the same deletion as the corresponding lymph node metastases. The other cases contained deletions either in the primary tumour (3 cases) or in the lymph node metastases (1 case) or no deletions at all (1 case).