Serum IGF-1 Scores and Clinical Outcomes in the Phase III IMbrave150 Study of Atezolizumab Plus Bevacizumab versus Sorafenib in Patients with Unresectable Hepatocellular Carcinoma.

Purpose: Child-Turcotte-Pugh class A (CTP-A) in unresectable hepatocellular carcinoma (HCC) is the standard criterion for active therapy and clinical trial enrollment. We hypothesized that insulin-like growth factor-1 (IGF-1) derived scores may provide improved survival prediction over CTP classification. This study aimed to evaluate the potential prognostic and predictive effects of IGF-1 derived scores in the phase III IMbrave150 study. Patients and Methods: Baseline and on-treatment serum IGF-1 levels from 371 patients were subjected to central analysis. Patients' IGF-1 score (1/2/3) and IGF-CTP score (A/B/C) were determined based on pre-specified cutoffs. Outcomes were analyzed by baseline and by on-treatment changes of the IGF-1 and IGF-CTP scores within and between the two treatment arms. The interaction between these scores and outcomes was assessed using univariate and multivariate analyses. Results: Baseline IGF-CTP score (A vs B/C) showed prognostic significance for OS in both the atezolizumab-bevacizumab (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.20-0.56; P<0.001) and sorafenib (HR, 0.32; 95% CI, 0.16-0.65; P=0.002) arms. Baseline IGF-1 score (1 vs 2/3) also showed prognostic significance for OS in both the atezolizumab-bevacizumab (HR, 0.33; 95% CI, 0.20-0.55; P<0.001) and sorafenib (HR, 0.48; 95% CI, 0.26-0.89; P=0.02) arms. HRs for PFS were consistent with those for OS. No significant predictive effects were observed for either score between the two arms. Kinetic analysis revealed that patients with increased IGF-1 score (1-> 2/3) at 3 weeks post treatment had shorter OS than patients with stable IGF-1 score of 1 in both the atezolizumab-bevacizumab (HR, 3.70; 95% CI, 1.56-8.77; P=0.003) and sorafenib (HR, 5.83; 95% CI, 1.88-18.12; P=0.0023) arms. Conclusion: Baseline and kinetic change of IGF-CTP and IGF-1 scores are independent prognostic factors for patients with unresectable HCC treated with atezolizumab-bevacizumab or sorafenib. These novel scores may provide improved patient stratification in future HCC clinical trials. IMbrave150 ClincialTrials.gov number, NCT03434379.

Molecular correlates of clinical response and resistance to atezolizumab in combination with bevacizumab in advanced hepatocellular carcinoma.

Atezolizumab (anti-programmed death-ligand 1 (PD-L1)) and bevacizumab (anti-vascular endothelial growth factor (VEGF)) combination therapy has become the new standard of care in patients with unresectable hepatocellular carcinoma. However, potential predictive biomarkers and mechanisms of response and resistance remain less well understood. We report integrated molecular analyses of tumor samples from 358 patients with hepatocellular carcinoma (HCC) enrolled in the GO30140 phase 1b or IMbrave150 phase 3 trial and treated with atezolizumab combined with bevacizumab, atezolizumab alone or sorafenib (multikinase inhibitor). Pre-existing immunity (high expression of CD274, T-effector signature and intratumoral CD8+ T cell density) was associated with better clinical outcomes with the combination. Reduced clinical benefit was associated with high regulatory T cell (Treg) to effector T cell (Teff) ratio and expression of oncofetal genes (GPC3, AFP). Improved outcomes from the combination versus atezolizumab alone were associated with high expression of VEGF Receptor 2 (KDR), Tregs and myeloid inflammation signatures. These findings were further validated by analyses of paired pre- and post-treatment biopsies, in situ analyses and in vivo mouse models. Our study identified key molecular correlates of the combination therapy and highlighted that anti-VEGF might synergize with anti-PD-L1 by targeting angiogenesis, Treg proliferation and myeloid cell inflammation.

Genome-wide association study identifies kallikrein 5 in type 2 inflammation-low asthma.

BACKGROUND: Clinical studies of type 2 (T2) cytokine-related neutralizing antibodies in asthma have identified a substantial subset of patients with low levels of T2 inflammation who do not benefit from T2 cytokine neutralizing antibody treatment. Non-T2 mechanisms are poorly understood in asthma but represent a redefined unmet medical need. OBJECTIVE: We sought to gain a better understanding of genetic contributions to T2-low asthma. METHODS: We utilized an unbiased genome-wide association study of patients with moderate to severe asthma stratified by T2 serum biomarker periostin. We also performed additional expression and biological analysis for the top genetic hits. RESULTS: We identified a novel protective single nucleotide polymorphism at chr19q13.41, which is selectively associated with T2-low asthma and establishes Kallikrein-related peptidase 5 (KLK5) as the causal gene mediating this association. Heterozygous carriers of the single nucleotide polymorphisms have reduced KLK5 expression. KLK5 is secreted by human bronchial epithelial cells and elevated in asthma bronchial alveolar lavage. T2 cytokines IL-4 and IL-13 downregulate KLK5 in human bronchial epithelial cells. KLK5, dependent on its catalytic function, induces epithelial chemokine/cytokine expression. Finally, overexpression of KLK5 in airway or lack of an endogenous KLK5 inhibitor, SPINK5, leads to spontaneous airway neutrophilic inflammation. CONCLUSION: Our data identify KLK5 to be the causal gene at a novel locus at chr19q13.41 associated with T2-low asthma.

TGFß2 and TGFß3 isoforms drive fibrotic disease pathogenesis.

Transforming growth factor-ß (TGFß) is a key driver of fibrogenesis. Three TGFß isoforms (TGFß1, TGFß2, and TGFß3) in mammals have distinct functions in embryonic development; however, the postnatal pathological roles and activation mechanisms of TGFß2 and TGFß3 have not been well characterized. Here, we show that the latent forms of TGFß2 and TGFß3 can be activated by integrin-independent mechanisms and have lower activation thresholds compared to TGFß1. Unlike TGFB1, TGFB2 and TGFB3 expression is increased in human lung and liver fibrotic tissues compared to healthy control tissues. Thus, TGFß2 and TGFß3 may play a pathological role in fibrosis. Inducible conditional knockout mice and anti-TGFß isoform-selective antibodies demonstrated that TGFß2 and TGFß3 are independently involved in mouse fibrosis models in vivo, and selective TGFß2 and TGFß3 inhibition does not lead to the increased inflammation observed with pan-TGFß isoform inhibition. A cocrystal structure of a TGFß2-anti-TGFß2/3 antibody complex reveals an allosteric isoform-selective inhibitory mechanism. Therefore, inhibiting TGFß2 and/or TGFß3 while sparing TGFß1 may alleviate fibrosis without toxicity concerns associated with pan-TGFß blockade.

The transition from normal lung anatomy to minimal and established fibrosis in idiopathic pulmonary fibrosis (IPF).

BACKGROUND: The transition from normal lung anatomy to minimal and established fibrosis is an important feature of the pathology of idiopathic pulmonary fibrosis (IPF). The purpose of this report is to examine the molecular and cellular mechanisms associated with this transition. METHODS: Pre-operative thoracic Multidetector Computed Tomography (MDCT) scans of patients with severe IPF (n = 9) were used to identify regions of minimal(n = 27) and established fibrosis(n = 27). MDCT, Micro-CT, quantitative histology, and next-generation sequencing were used to compare 24 samples from donor controls (n = 4) to minimal and established fibrosis samples. FINDINGS: The present results extended earlier reports about the transition from normal lung anatomy to minimal and established fibrosis by showing that there are activations of TGFBI, T cell co-stimulatory genes, and the down-regulation of inhibitory immune-checkpoint genes compared to controls. The expression patterns of these genes indicated activation of a field immune response, which is further supported by the increased infiltration of inflammatory immune cells dominated by lymphocytes that are capable of forming lymphoid follicles. Moreover, fibrosis pathways, mucin secretion, surfactant, TLRs, and cytokine storm-related genes also participate in the transitions from normal lung anatomy to minimal and established fibrosis. INTERPRETATION: The transition from normal lung anatomy to minimal and established fibrosis is associated with genes that are involved in the tissue repair processes, the activation of immune responses as well as the increased infiltration of CD4, CD8, B cell lymphocytes, and macrophages. These molecular and cellular events correlate with the development of structural abnormality of IPF and probably contribute to its pathogenesis.

Molecular Subsets in Renal Cancer Determine Outcome to Checkpoint and Angiogenesis Blockade.

Integrated multi-omics evaluation of 823 tumors from advanced renal cell carcinoma (RCC) patients identifies molecular subsets associated with differential clinical outcomes to angiogenesis blockade alone or with a checkpoint inhibitor. Unsupervised transcriptomic analysis reveals seven molecular subsets with distinct angiogenesis, immune, cell-cycle, metabolism, and stromal programs. While sunitinib and atezolizumab + bevacizumab are effective in subsets with high angiogenesis, atezolizumab + bevacizumab improves clinical benefit in tumors with high T-effector and/or cell-cycle transcription. Somatic mutations in PBRM1 and KDM5C associate with high angiogenesis and AMPK/fatty acid oxidation gene expression, while CDKN2A/B and TP53 alterations associate with increased cell-cycle and anabolic metabolism. Sarcomatoid tumors exhibit lower prevalence of PBRM1 mutations and angiogenesis markers, frequent CDKN2A/B alterations, and increased PD-L1 expression. These findings can be applied to molecularly stratify patients, explain improved outcomes of sarcomatoid tumors to checkpoint blockade versus antiangiogenics alone, and develop personalized therapies in RCC and other indications.

IL-17A is associated with the breakdown of the blood-brain barrier in relapsing-remitting multiple sclerosis.

IL-17 has been implicated in the pathogenesis of multiple sclerosis (MS). Here, we show that blockade of IL-17A, but not IL-17F, attenuated experimental autoimmune encephalomyelitis (EAE). We further show that IL-17A levels were elevated in the CSF of relapsing-remitting MS (RRMS) patients and that they correlated with the CSF/serum albumin quotient (Qalb), a measure of blood-brain barrier (BBB) dysfunction. We then demonstrated that the combination of IL-17A and IL-6 reduced the expression of tight junction (TJ)-associated genes and disrupted monolayer integrity in the BBB cell line hCMEC/D3. However, unlike IL-17A, IL-6 in the CSF from RRMS patients did not correlate with Qalb. These data highlight the potential importance of targeting IL-17A in preserving BBB integrity in RRMS.

Analysis of protein-altering variants in telomerase genes and their association with MUC5B common variant status in patients with idiopathic pulmonary fibrosis: a candidate gene sequencing study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) risk has a strong genetic component. Studies have implicated variations at several loci, including TERT, surfactant genes, and a single nucleotide polymorphism at chr11p15 (rs35705950) in the intergenic region between TOLLIP and MUC5B. Patients with IPF who have risk alleles at rs35705950 have longer survival from the time of IPF diagnosis than do patients homozygous for the non-risk allele, whereas patients with shorter telomeres have shorter survival times. We aimed to assess whether rare protein-altering variants in genes regulating telomere length are enriched in patients with IPF homozygous for the non-risk alleles at rs35705950. METHODS: Between Nov 1, 2014, and Nov 1, 2016, we assessed blood samples from patients aged 40 years or older and of European ancestry with sporadic IPF from three international phase 3 clinical trials (INSPIRE, CAPACITY, ASCEND), one phase 2 study (RIFF), and US-based observational studies (Vanderbilt Clinical Interstitial Lung Disease Registry and the UCSF Interstitial Lung Disease Clinic registry cohorts) at the Broad Institute (Cambridge, MA, USA) and Human Longevity (San Diego, CA, USA). We also assessed blood samples from non-IPF controls in several clinical trials. We did whole-genome sequencing to assess telomere length and identify rare protein-altering variants, stratified by rs35705950 genotype. We also assessed rare functional variation in TERT exons and compared telomere length and disease progression across genotypes. FINDINGS: We assessed samples from 1510 patients with IPF and 1874 non-IPF controls. 30 (3%) of 1046 patients with an rs35705950 risk allele had a rare protein-altering variant in TERT compared with 34 (7%) of 464 non-risk allele carriers (odds ratio 0·40 [95% CI 0·24-0·66], p=0·00039). Subsequent analyses identified enrichment of rare protein-altering variants in PARN and RTEL1, and rare variation in TERC in patients with IPF compared with controls. We expanded our study population to provide a more accurate estimation of rare variant frequency in these four loci, and to calculate telomere length. The proportion of patients with at least one rare variant in TERT, PARN, TERC, or RTEL1 was higher in patients with IPF than in controls (149 [9%] of 1739 patients vs 205 [2%] of 8645 controls, p=2·44 × 10-8). Patients with IPF who had a variant in any of the four identified telomerase component genes had telomeres that were 3·69-16·10% shorter than patients without a variant in any of the four genes and had an earlier mean age of disease onset than patients without one or more variants (65·1 years [SD 7·8] vs 67·1 years [7·9], p=0·004). In the placebo arms of clinical trials, shorter telomeres were significantly associated with faster disease progression (1·7% predicted forced vital capacity per kb per year, p=0·002). Pirfenidone had treatment benefit regardless of telomere length (p=4·24 × 10-8 for telomere length lower than the median, p=0·0044 for telomere length greater than the median). INTERPRETATION: Rare protein-altering variants in TERT, PARN, TERC, and RTEL1 are enriched in patients with IPF compared with controls, and, in the case of TERT, particularly in individuals without a risk allele at the rs35705950 locus. This suggests that multiple genetic factors contribute to sporadic IPF, which might implicate distinct mechanisms of pathogenesis and disease progression. FUNDING: Genentech, National Institutes of Health, Francis Family Foundation, Pulmonary Fibrosis Foundation, Nina Ireland Program for Lung Health, US Department of Veterans Affairs.

Ubiquilin1 promotes antigen-receptor mediated proliferation by eliminating mislocalized mitochondrial proteins.

Ubiquilins (Ubqlns) are a family of ubiquitin receptors that promote the delivery of hydrophobic and aggregated ubiquitinated proteins to the proteasome for degradation. We carried out a proteomic analysis of a B cell lymphoma-derived cell line, BJAB, that requires UBQLN1 for survival to identify UBQLN1 client proteins. When UBQLN1 expression was acutely inhibited, 120 mitochondrial proteins were enriched in the cytoplasm, suggesting that the accumulation of mitochondrial client proteins in the absence of UBQLN1 is cytostatic. Using a Ubqln1-/- mouse strain, we found that B cell receptor (BCR) ligation of Ubqln1-/- B cells led to a defect in cell cycle entry. As in BJAB cells, mitochondrial proteins accumulated in BCR-stimulated cells, leading to protein synthesis inhibition and cell cycle block. Thus, UBQLN1 plays an important role in clearing mislocalized mitochondrial proteins upon cell stimulation, and its absence leads to suppression of protein synthesis and cell cycle arrest.

Peptidoglycan Association of Murein Lipoprotein Is Required for KpsD-Dependent Group 2 Capsular Polysaccharide Expression and Serum Resistance in a Uropathogenic Escherichia coli Isolate.

Murein lipoprotein (Lpp) and peptidoglycan-associated lipoprotein (Pal) are major outer membrane lipoproteins in Escherichia coli Their roles in cell-envelope integrity have been documented in E. coli laboratory strains, and while Lpp has been linked to serum resistance in vitro, the underlying mechanism has not been established. Here, lpp and pal mutants of uropathogenic E. coli strain CFT073 showed reduced survival in a mouse bacteremia model, but only the lpp mutant was sensitive to serum killing in vitro The peptidoglycan-bound Lpp form was specifically required for preventing complement-mediated bacterial lysis in vitro and complement-mediated clearance in vivo Compared to the wild-type strain, the lpp mutant had impaired K2 capsular polysaccharide production and was unable to respond to exposure to serum by elevating capsular polysaccharide amounts. These properties correlated with altered cellular distribution of KpsD, the predicted outer membrane translocon for "group 2" capsular polysaccharides. We identified a novel Lpp-dependent association between functional KpsD and peptidoglycan, highlighting important interplay between cell envelope components required for resistance to complement-mediated lysis in uropathogenic E. coli isolates.IMPORTANCE Uropathogenic E. coli (UPEC) isolates represent a significant cause of nosocomial urinary tract and bloodstream infections. Many UPEC isolates are resistant to serum killing. Here, we show that a major cell-envelope lipoprotein (murein lipoprotein) is required for serum resistance in vitro and for complement-mediated bacterial clearance in vivo This is mediated, in part, through a novel mechanism by which murein lipoprotein affects the proper assembly of a key component of the machinery involved in production of "group 2" capsules. The absence of murein lipoprotein results in impaired production of the capsule layer, a known participant in complement resistance. These results demonstrate an important role for murein lipoprotein in complex interactions between different outer membrane biogenesis pathways and further highlight the importance of lipoprotein assembly and transport in bacterial pathogenesis.

A CEACAM6-High Airway Neutrophil Phenotype and CEACAM6-High Epithelial Cells Are Features of Severe Asthma.

Severe asthma represents a major unmet clinical need; understanding the pathophysiology is essential for the development of new therapies. Using microarray analysis, we previously found three immunological clusters in asthma: Th2-high, Th17-high, and Th2/17-low. Although new therapies are emerging for Th2-high disease, identifying molecular pathways in Th2-low disease remains an important goal. Further interrogation of our previously described microarray dataset revealed upregulation of gene expression for carcinoembryonic Ag cell adhesion molecule (CEACAM) family members in the bronchi of patients with severe asthma. Our aim was therefore to explore the distribution and cellular localization of CEACAM6 using immunohistochemistry on bronchial biopsy tissue obtained from patients with mild-to-severe asthma and healthy control subjects. Human bronchial epithelial cells were used to investigate cytokine and corticosteroid in vitro regulation of CEACAM6 gene expression. CEACAM6 protein expression in bronchial biopsies was increased in airway epithelial cells and lamina propria inflammatory cells in severe asthma compared with healthy control subjects. CEACAM6 in the lamina propria was localized to neutrophils predominantly. Neutrophil density in the bronchial mucosa was similar across health and the spectrum of asthma severity, but the percentage of neutrophils expressing CEACAM6 was significantly increased in severe asthma, suggesting the presence of an altered neutrophil phenotype. CEACAM6 gene expression in cultured epithelial cells was upregulated by wounding and neutrophil elastase. In summary, CEACAM6 expression is increased in severe asthma and primarily associated with airway epithelial cells and tissue neutrophils. CEACAM6 may contribute to the pathology of treatment-resistant asthma via neutrophil and airway epithelial cell-dependent pathways.

CXCL14 is a candidate biomarker for Hedgehog signalling in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is associated with aberrant expression of developmental pathways, including Hedgehog (Hh). As Hh signalling contributes to multiple pro-fibrotic processes, Hh inhibition may represent a therapeutic option for IPF. However, no non-invasive biomarkers are available to monitor lung Hh activity. METHODS: We assessed gene and protein expression in IPF and control lung biopsies, mouse lung, fibroblasts stimulated in vitro with sonic hedgehog (SHh), and plasma in IPF patients versus controls, and cancer patients before and after treatment with vismodegib, a Hh inhibitor. RESULTS: Lung tissue from IPF patients exhibited significantly greater expression of Hh-related genes versus controls. The gene most significantly upregulated in both IPF lung biopsies and fibroblasts stimulated in vitro with SHh was CXCL14, which encodes a soluble secreted chemokine whose expression is inhibited in vitro by the addition of vismodegib. CXCL14 expression was induced by SHh overexpression in mouse lung. Circulating CXCL14 protein levels were significantly higher in plasma from IPF patients than controls. In cancer patients, circulating CXCL14 levels were significantly reduced upon vismodegib treatment. CONCLUSIONS: CXCL14 is a systemic biomarker that could be used to identify IPF patients with increased Hh pathway activity and monitor the pharmacodynamic effects of Hh antagonist therapy in IPF. TRIAL REGISTRATION NUMBER: Post-results, NCT00968981.

TH2 and TH17 inflammatory pathways are reciprocally regulated in asthma.

Increasing evidence suggests that asthma is a heterogeneous disorder regulated by distinct molecular mechanisms. In a cross-sectional study of asthmatics of varying severity (n = 51), endobronchial tissue gene expression analysis revealed three major patient clusters: TH2-high, TH17-high, and TH2/17-low. TH2-high and TH17-high patterns were mutually exclusive in individual patient samples, and their gene signatures were inversely correlated and differentially regulated by interleukin-13 (IL-13) and IL-17A. To understand this dichotomous pattern of T helper 2 (TH2) and TH17 signatures, we investigated the potential of type 2 cytokine suppression in promoting TH17 responses in a preclinical model of allergen-induced asthma. Neutralization of IL-4 and/or IL-13 resulted in increased TH17 cells and neutrophilic inflammation in the lung. However, neutralization of IL-13 and IL-17 protected mice from eosinophilia, mucus hyperplasia, and airway hyperreactivity and abolished the neutrophilic inflammation, suggesting that combination therapies targeting both pathways may maximize therapeutic efficacy across a patient population comprising both TH2 and TH17 endotypes.

Association of the interferon signature metric with serological disease manifestations but not global activity scores in multiple cohorts of patients with SLE.

OBJECTIVES: The interferon (IFN) signature (IS) in patients with systemic lupus erythematosus (SLE) includes over 100 genes induced by type I IFN pathway activation. We developed a method to quantify the IS using three genes-the IS metric (ISM)-and characterised the clinical characteristics of patients with SLE with different ISM status from multiple clinical trials. METHODS: Blood microarray expression data from a training cohort of patients with SLE confirmed the presence of the IS and identified surrogate genes. We assayed these genes in a quantitative PCR (qPCR) assay, yielding an ISM from the IS. The association of ISM status with clinical disease characteristics was assessed in patients with extrarenal lupus and lupus nephritis from four clinical trials. RESULTS: Three genes, HERC5, EPSTI and CMPK2, correlated well with the IS (p>0.96), and composed the ISM qPCR assay. Using the 95th centile for healthy control data, patients with SLE from different studies were classified into two ISM subsets-ISM-Low and ISM-High-that are longitudinally stable over 36 weeks. Significant associations were identified between ISM-High status and higher titres of anti-dsDNA antibodies, presence of anti extractable nuclear antigen autoantibodies, elevated serum B cell activating factor of the tumour necrosis factor family (BAFF) levels, and hypocomplementaemia. However, measures of overall clinical disease activity were similar for ISM-High and ISM-Low groups. CONCLUSIONS: The ISM is an IS biomarker that divides patients with SLE into two subpopulations-ISM-High and ISM-Low-with differing serological manifestations. The ISM does not distinguish between high and low disease activity, but may have utility in identifying patients more likely to respond to treatment(s) targeting IFN-α. CLINICALTRIALSGOV REGISTRATION NUMBER: NCT00962832.

Heterogeneous gene expression signatures correspond to distinct lung pathologies and biomarkers of disease severity in idiopathic pulmonary fibrosis.

BACKGROUND: There is microscopic spatial and temporal heterogeneity of pathological changes in idiopathic pulmonary fibrosis (IPF) lung tissue, which may relate to heterogeneity in pathophysiological mediators of disease and clinical progression. We assessed relationships between gene expression patterns, pathological features, and systemic biomarkers to identify biomarkers that reflect the aggregate disease burden in patients with IPF. METHODS: Gene expression microarrays (N=40 IPF; 8 controls) and immunohistochemical analyses (N=22 IPF; 8 controls) of lung biopsies. Clinical characterisation and blood biomarker levels of MMP3 and CXCL13 in a separate cohort of patients with IPF (N=80). RESULTS: 2940 genes were significantly differentially expressed between IPF and control samples (|fold change| >1.5, p<0.05). Two clusters of co-regulated genes related to bronchiolar epithelium or lymphoid aggregates exhibited substantial heterogeneity within the IPF population. Gene expression in bronchiolar and lymphoid clusters corresponded to the extent of bronchiolisation and lymphoid aggregates determined by immunohistochemistry in adjacent tissue sections. Elevated serum levels of MMP3, encoded in the bronchiolar cluster, and CXCL13, encoded in the lymphoid cluster, corresponded to disease severity and shortened survival time (p<10(-7) for MMP3 and p<10(-5) for CXCL13; Cox proportional hazards model). CONCLUSIONS: Microscopic pathological heterogeneity in IPF lung tissue corresponds to specific gene expression patterns related to bronchiolisation and lymphoid aggregates. MMP3 and CXCL13 are systemic biomarkers that reflect the aggregate burden of these pathological features across total lung tissue. These biomarkers may have clinical utility as prognostic and/or surrogate biomarkers of disease activity in interventional studies in IPF.

Endogenously expressed IL-13Rα2 attenuates IL-13-mediated responses but does not activate signaling in human lung fibroblasts.

IL-13 can bind to two distinct receptors: a heterodimer of IL-13Rα1/IL-4Rα and IL-13Rα2. Whereas IL-13Rα1/IL-4Rα engagement by IL-13 leads to the activation of STAT6, the molecular events triggered by IL-13 binding to IL-13Rα2 remain incompletely understood. IL-4 can bind to and signal through the IL-13Rα1/IL-4Rα complex but does not interact with IL-13Rα2. Idiopathic pulmonary fibrosis is a progressive and generally fatal parenchymal lung disease of unknown etiology with no current pharmacologic treatment options that substantially prolong survival. Preclinical models of fibrotic diseases have implicated IL-13 activity on multiple cell types, including macrophages and fibroblasts, in initiating and perpetuating pathological fibrosis. In this study, we show that IL-13, IL-4, IL-13Rα2, and IL-13-inducible target genes are expressed at significantly elevated levels in lung tissue from patients with idiopathic pulmonary fibrosis compared with control lung tissue. IL-4 and IL-13 induce virtually identical transcriptional responses in human monocytes, macrophages, and lung fibroblasts. IL-13Rα2 expression can be induced in lung fibroblasts by IL-4 or IL-13 via a STAT6-dependent mechanism, or by TNF-α via a STAT6-independent mechanism. Endogenously expressed IL-13Rα2 decreases, but does not abolish, sensitivity of lung fibroblasts to IL-13 and does not affect sensitivity to IL-4. Genome-wide transcriptional analyses of lung fibroblasts stimulated with IL-13 in the presence of Abs that selectively block interactions of IL-13 with IL-13Rα1/IL-4Rα or IL-13Rα2 show that endogenously expressed IL-13Rα2 does not activate any unique IL-13-mediated gene expression patterns, confirming its role as a decoy receptor for IL-13 signaling.

Safety and pharmacodynamics of rontalizumab in patients with systemic lupus erythematosus: results of a phase I, placebo-controlled, double-blind, dose-escalation study.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the presence of autoantibodies and inflammation in multiple organ systems. Elevation of messenger RNA levels of interferon (IFN)-regulated genes (IRGs) has been described in the peripheral blood of SLE patients and has been associated with disease activity. The safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of rontalizumab, a humanized IgG1 monoclonal antibody that neutralizes IFNα, were assessed in a phase I dose-escalation study of single and repeat doses of rontalizumab in adults with mildly active SLE. The present report describes the safety results and the impact of rontalizumab on expression of IRGs, IFN-inducible proteins, and autoantibodies. METHODS: Patients were enrolled into dose groups ranging from 0.3 to 10 mg/kg, administered via intravenous (IV) or subcutaneous routes. Expression levels of 7 IRGs and IFN-inducible serum proteins were monitored as potential biomarkers for the PD activity of rontalizumab. RESULTS: An acceptable safety profile was demonstrated for rontalizumab in patients with SLE. Prespecified criteria for dose-limiting toxicity were not met. The incidence of serious adverse events was comparable across cohorts. The PK properties were as expected for an IgG1 monoclonal antibody and were proportional to dose. Following administration of rontalizumab, a rapid decline in the expression of IRGs was observed in the 3 mg/kg and 10 mg/kg IV cohorts, and this effect could be sustained with repeat dosing. There was no apparent decline in the levels of IFN-inducible proteins or levels of anti-double-stranded DNA and anti-extractable nuclear antigen autoantibodies following treatment with rontalizumab. CONCLUSION: The preliminary safety, PK profile, and observed PD effects of rontalizumab support further evaluation of its safety and efficacy in SLE.

Increased expression of immunoreactive thymic stromal lymphopoietin in patients with severe asthma.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a cytokine implicated in the pathophysiology of asthma through 2 distinct pathways: a TSLP-OX40 ligand (OX40L)-T cell axis and a TSLP-mast cell axis. Whether these pathways are active in human asthma is unknown. OBJECTIVE: We sought to investigate whether mucosal TSLP protein expression relates to asthma severity and distinct immunologic pathways. METHODS: In healthy subjects and patients with mild-to-severe asthma, we immunostained bronchial biopsy specimens for TSLP, OX40, OX40L, T(H)2 cytokines, and inflammatory cell markers. We examined gene expression using RNA microarrays and quantitative RT-PCR. RESULTS: There was considerable heterogeneity in the levels of TSLP, IL-13, and IL-4 immunostaining across the cohort of asthmatic patients examined. Overall, TSLP protein expression was significantly increased in airway epithelium and lamina propria of asthmatic patients, particularly in patients with severe asthma. TSLP immunostaining in both compartments correlated with the severity of airflow obstruction. The majority of leukocytes expressing IL-13 were possibly nuocytes. Accounting for intersubject variability, the 55% of asthmatic patients with increased IL-13 immunostaining in the lamina propria also had increased IL-4 and TSLP expression. This was further substantiated by significant correlations between TSLP gene expression, a T(H)2 gene expression signature, and eosinophilic inflammation in bronchial biopsy specimens. Immunostaining for OX40, OX40L, and CD83 was sparse, with no difference between asthmatic patients and healthy subjects. CONCLUSION: TSLP expression is increased in a subset of patients with severe asthma in spite of high-dose inhaled or oral corticosteroid therapy. Targeting TSLP might only be efficacious in the subset of asthma characterized by increased TSLP expression and T(H)2 inflammation.