Coline H.M. van Moorsel

Surfactant Protein C Mutations Are the Basis of a Significant Portion of Adult Familial Pulmonary Fibrosis in a Dutch Cohort

RATIONALE Familial clustering of adult idiopathic interstitial pneumonias (IIP) suggests that genetic factors might play an important role in disease development. Mutations in the gene encoding surfactant protein C (SFTPC) have been found in children and families with idiopathic pneumonias, whereas cocarriage of a mutation in ATP-binding cassette subfamily A member 3 (ABCA3) was postulated to have a disease-modifying effect. OBJECTIVES To investigate the contribution of SFTPC mutations to adult familial pulmonary fibrosis (FPF) and the disease-modifying effect of mutations in ABCA3 within their families. METHODS Twenty-two unrelated patients with FPF (10%) were identified within our single-center cohort of 229 patients with IIP. SFTPC was sequenced in 20 patients with FPF and 20 patients with sporadic IIP. In patients with an SFTPC mutation, sequencing of ABCA3 was performed. Discovered variants were typed in more than 100 control subjects and 121 additional patients with sporadic IIP. MEASUREMENTS AND MAIN RESULTS In 5/20 unrelated patients with FPF (25%; confidence interval, 10-49) a mutation in SFTPC was detected: M71V, IVS4+2, and three times I73T. No mutations were detected in the sporadic or control cohort. Patients with SFTPC mutations presented with a histopathological pattern of usual interstitial pneumonia and nodular septa thickening and multiple lung cysts in combination with ground glass or diffuse lung involvement on chest high-resolution computed tomography. Two variants in ABCA3 were found in adult patients with FPF but not in affected children. CONCLUSIONS Mutations in SFTPC are a frequent cause of FPF in adult patients in our cohort. Nonclassifiable radiological patterns with cystic changes and histopathological patterns of usual interstitial pneumonia are characteristics of adult SFTPC mutation carriers.

Methotrexate vs Azathioprine in Second-line Therapy of Sarcoidosis

BACKGROUND Steroids remain the first-choice therapeutic in sarcoidosis; however, long-term use is associated with toxicity. Evidence defining the best second-line therapeutic is currently lacking. The aim of this study was to compare the effect of methotrexate and azathioprine on prednisone tapering, pulmonary function, and side effects in the second-line treatment of sarcoidosis. METHODS An international retrospective cohort study was performed, reviewing all patients with sarcoidosis who started methotrexate or azathioprine until 2 years after initiation or discontinuation. A linear mixed model with FEV1, vital capacity (VC), diffusing capacity of lung for carbon monoxide (DLCO), and prednisone dose changes over time as end points was used. Side effects were compared with χ2 tests. RESULTS Two hundred patients were included, of whom 145 received methotrexate and 55 azathioprine. Prednisone daily dose decreased a mean of 6.32 mg/y (P < .0001) while on therapy, with a similar steroid-sparing capacity for methotrexate and azathioprine. Of all patients completing 1 year of therapy, 70% had a reduction in daily prednisone dose of at least 10 mg. FEV1 showed a mean increase of 52 mL/y (P = .006) and VC of 95 mL/y (P = .001) in both treatment groups. DLCO % predicted increased, with a mean of 1.23%/y (P = .018). There were more patients with infections in the azathioprine group (34.6% vs 18.1%, P = .01), but no differences regarding other side effects. CONCLUSIONS This retrospective study comparing the effect of second-line therapy in sarcoidosis shows that both methotrexate and azathioprine have significant steroid-sparing potency, a similar positive effect on lung function, and comparable side effects, except for a higher infection rate in the azathioprine group.

Prediction of relapse after discontinuation of infliximab therapy in severe sarcoidosis

Infliximab is effective as a third-line therapeutic for severe sarcoidosis; however, long-term efficacy is unknown. The aim of this study was to assess the relapse rate after discontinuation of infliximab in sarcoidosis patients and predict relapse by analysis of the activity marker soluble interleukin (IL)-2 receptor (sIL-2R) and maximum standardised uptake value (SUVmax) of 18F-fluorodeoxyglucose positron emission tomography (FDG PET). In this retrospective cohort study, the proportion of relapse was analysed using the Kaplan–Meier method and predicting factors were studied using Cox regression. 47 sarcoidosis patients who started infliximab therapy were included in the risk analysis. Kaplan–Meier analysis revealed a median time to relapse of 11.1 months and showed that 25% of the cohort relapsed within 4 months. Both mediastinal SUVmax ≥6.0 on FDG PET (hazard ratio 3.77, p<0.001) and serum sIL-2R ≥4000 pg·mL−1 (hazard ratio 2.24, p=0.033) at start of therapy predicted relapse. In multivariate analysis, a mediastinal SUVmax ≥6.0 at initiation of therapy was an independent predictor of relapse (hazard ratio 4.33, p<0.001). The majority of patients that discontinued infliximab therapy relapsed. High serum sIL-2R and high SUVmax on FDG PET at initiation of therapy were significant predictors of relapse. These results suggest close monitoring of patients in this category when they discontinue infliximab treatment. Two significant predictors of relapse after discontinuation of infliximab therapy for severe sarcoidosis http://ow.ly/qXWuq

IL1RN genetic variations and risk of IPF: a meta-analysis and mRNA expression study

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating lung disease of unknown aetiology. Genetic variations in the IL1RN gene, encoding the interleukin-1 receptor antagonist (IL-1Ra), have been associated with IPF susceptibility. Several studies investigated the variable number tandem repeat (VNTR) or single nucleotide polymorphisms rs408392, rs419598 and rs2637988, with variable results. The aim of this study was to elucidate the influence of polymorphisms in IL1RN on IPF susceptibility and mRNA expression. We performed a meta-analysis of the five case–control studies that investigated an IL1RN polymorphism in IPF in a Caucasian population. In addition, we investigated whether IL1RN mRNA expression was influenced by IL1RN polymorphisms. The VNTR, rs408392 and rs419598 were in tight linkage disequilibrium, with D′ > 0.99. Furthermore, rs2637988 was in linkage disequilibrium with the VNTR (D′ = 0.90). A haploblock of VNTR*2 and the minor alleles of rs408392and rs419598 was constructed. Meta-analysis revealed that this VNTR*2 haploblock is associated with IPF susceptibility both with an allelic model (odds ratio = 1.42, p = 0.002) and a carriership model (odds ratio = 1.60, p = 0.002). IL1RN mRNA expression was significantly influenced by rs2637988, with lower levels found in carriers of the (minor) GG genotype (p < 0.001). From this meta-analysis, we conclude that the VNTR*2 haploblock is associated with susceptibility to IPF. In addition, polymorphisms in IL1RN influence IL-1Ra mRNA expression, suggesting that lower levels of IL-1Ra predispose to developing IPF. Together these findings demonstrate that the cytokine IL-1Ra plays a role in IPF pathogenesis.

Effectiveness of infliximab in refractory FDG PET-positive sarcoidosis.

Inconclusive evidence for the efficacy of infliximab in sarcoidosis hinders the global use of this potentially beneficial drug. To study infliximab efficacy in a clinical setting, we performed a prospective open-label trial in patients refractory to conventional treatment. Patients (n=56) received eight infusions of 5 mg·kg-1 infliximab. Pulmonary function, disease activity measured by 18F-fluorodeoxyglucose (FDG) by positron emission tomography (PET) and quality of life were part of the clinical work-up. Infliximab levels were measured before every infusion. After 26 weeks of infliximab treatment, mean improvement in forced vital capacity (FVC) was 6.6% predicted (p=0.0007), whereas in the 6 months before start of treatment, lung function decreased. Maximum standardised uptake value (SUVmax) of pulmonary parenchyma on 18F-FDG PET decreased by 3.93 (p<0.0001). High SUVmax of pulmonary parenchyma at baseline predicted FVC improvement (R=0.62, p=0.0004). An overall beneficial response was seen in 79% of patients and a partial response was seen in 17% of patients. No correlation between infliximab trough level (mean 18.0 µg·mL-1) and initial response was found. In conclusion, infliximab causes significant improvement in FVC in refractory 18F-FDG PET positive sarcoidosis. Especially in pulmonary disease, high 18F-FDG PET SUVmax values at treatment initiation predict clinically relevant lung function improvement. These results suggest that inclusion of 18F-FDG PET is useful in therapeutic decision-making in complex sarcoidosis. Infliximab is highly effective in refractory 18F-FDG PET positive sarcoidosis patients http://ow.ly/JoxhL

Polymorphisms in innate immunity genes associated with development of bronchiolitis obliterans after lung transplantation

BACKGROUND Activation of the immune system is suggested to prevent transplant tolerance and to promote the development of bronchiolitis obliterans syndrome (BOS). The innate immune system is activated by the interaction of pathogen-associated molecular patterns of microorganisms with Toll-like receptors (TLRs). Activation of innate immunity via TLRs was shown to be a barrier to the induction of transplantation tolerance after lung transplantation. We hypothesized that polymorphisms in 10 genes coding for TLR1 to TLR10 might contribute to an altered immune response and the subsequent development of BOS. METHODS DNA was collected from 110 lung transplant recipients. Twenty patients developed BOS. The control group comprised 422 individuals. Sixty-four single-nucleotide polymorphisms (SNPs) in 10 genes coding for TLR1 to TLR10 were genotyped. RESULTS The genotype distribution of TLR2 (rs1898830 and rs7656411), TLR4 (rs1927911) and TLR9 (rs352162 and rs187084) was significantly different between BOS(pos) patients and BOS(neg) patients and controls. The BOS(pos) group had significantly more patients with 3 or 4 of these risk alleles compared with the BOS(neg) and control groups. CONCLUSIONS Polymorphisms in TLR2, TLR4 and TLR9 that recognize bacterial and viral pathogens are associated with BOS after lung transplantation.

Association between Variations in Cell Cycle Genes and Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating and progressive lung disease. Its aetiology is thought to involve damage to the epithelium and abnormal repair. Alveolar epithelial cells near areas of remodelling show an increased expression of proapoptotic molecules. Therefore, we investigated the role of genes involved in cell cycle control in IPF. Genotypes for five single nucleotide polymorphisms (SNPs) in the tumour protein 53 (TP53) gene and four SNPs in cyclin-dependent kinase inhibitor 1A (CDKN1A), the gene encoding p21, were determined in 77 IPF patients and 353 controls. In peripheral blood mononuclear cells (PBMC) from 16 healthy controls mRNA expression of TP53 and CDKN1A was determined. Rs12951053 and rs12602273, in TP53, were significantly associated with survival in IPF patients. Carriers of a minor allele had a 4-year survival of 22% versus 57% in the non-carrier group (p = 0.006). Rs2395655 and rs733590, in CDKN1A, were associated with an increased risk of developing IPF. In addition, the rs2395655 G allele correlated with progression of the disease as it increased the risk of a rapid decline in lung function. Functional experiments showed that rs733590 correlated significantly with CDKN1A mRNA expression levels in healthy controls. This is the first study to show that genetic variations in the cell cycle genes encoding p53 and p21 are associated with IPF disease development and progression. These findings support the idea that cell cycle control plays a role in the pathology of IPF. Variations in TP53 and CDKN1A can impair the response to cell damage and increase the loss of alveolar epithelial cells.

High-Density Genetic Mapping Identifies New Susceptibility Variants in Sarcoidosis Phenotypes and Shows Genomic-driven Phenotypic Differences.

RATIONALE Sarcoidosis is a multisystem disease of unknown cause. Löfgrens 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.

Telomere Length in Interstitial Lung Diseases

BACKGROUND Interstitial lung disease (ILD) is a heterogeneous group of rare diseases that primarily affect the pulmonary interstitium. Studies have implicated a role for telomere length (TL) maintenance in ILD, particularly in idiopathic interstitial pneumonia (IIP). Here, we measure TL in a wide spectrum of sporadic and familial cohorts of ILD and compare TL between patient cohorts and control subjects. METHODS A multiplex quantitative polymerase chain reaction method was used to measure TL in 173 healthy subjects and 359 patients with various ILDs, including familial interstitial pneumonia (FIP). The FIP cohort was divided into patients carrying TERT mutations, patients carrying SFTPA2 or SFTPC mutations, and patients without a proven mutation (FIP-no mutation). RESULTS TL in all cases of ILD was significantly shorter compared with those of control subjects (P range: .038 to < .0001). Furthermore, TL in patients with idiopathic pulmonary fibrosis (IPF) was significantly shorter than in patients with other IIPs (P = .002) and in patients with sarcoidosis (P < .0001). Within the FIP cohort, patients in the FIP-telomerase reverse transcriptase (TERT) group had the shortest telomeres (P < .0001), and those in the FIP-no mutation group had TL comparable to that of patients with IPF (P = .049). Remarkably, TL of patients with FIP-surfactant protein (SFTP) was significantly longer than in patients with IPF, but similar to that observed in patients with other sporadic IIPs. CONCLUSIONS The results show telomere shortening across all ILD diagnoses. The difference in TL between the FIP-TERT and FIP-SFTP groups indicates the distinction between acquired and innate telomere shortening. Short TL in the IPF and FIP-no mutation groups is indicative of an innate telomere-biology defect, while a stress-induced, acquired telomere shortening might be the underlying process for the other ILD diagnoses.

Systemic and exhaled cytokine and chemokine profiles are associated with the development of bronchiolitis obliterans syndrome

BACKGROUND The mechanisms that lead to the fibrotic obliteration in bronchiolitis obliterans syndrome (BOS) may involve the interactions between T-helper (Th)1 and Th2 cytokines. The aim of this study is to determine the Th1 and Th2 cytokine and chemokine profiles in serum and exhaled breath condensate (EBC) in lung transplant recipients and to assess their usefulness as biomarkers to predict the development of BOS. METHODS Serum and EBC from 10 patients with BOS (BOS(pos)) and 10 patients without BOS (BOS(neg)), matched for clinical and demographic variables, were analyzed with a multiplex immunoassay to measure a panel of 27 cytokines and chemokines. RESULTS The pro-inflammatory cytokines in serum were elevated in lung transplant recipients compared with controls. BOS(pos) patients had significantly lower concentrations of interleukin (IL)-4, IL-13, and vascular endothelial growth factor (VEGF) compared with BOS(neg) patients. The concentration of IL-5, however, was significantly higher in BOS(pos) patients. Levels of IL-4 and IL-5 were hardly detectable in EBC. IL-13 and VEGF, both decreased in serum in BOS(pos) patients, were also decreased in EBC in BOS(pos) patients compared with BOS(neg) patients. Longitudinal analysis of cytokines and chemokines in serum and EBC from the time of lung transplantation onwards did not reveal significant trends in cytokines and chemokines that preceded the diagnosis of BOS. CONCLUSIONS Levels of pro-inflammatory cytokines were increased in lung transplant recipients compared with controls. From the moment of transplantation onwards, there is a different pattern of Th2 cytokines in serum in BOS(pos) patients than in BOS(neg) patients.