Explore the vast range of titles available.

The processes that drive fibrotic diseases are complex and include an influx of peripheral blood monocytes that can differentiate into fibroblast-like cells called fibrocytes. Monocytes can also differentiate into other cell types, such as tissue macrophages. The ability to discriminate between monocytes, macrophages, fibrocytes, and fibroblasts in fibrotic lesions could be beneficial in identifying therapies that target either stromal fibroblasts or fibrocytes. We have identified markers that discriminate between human peripheral blood monocytes, tissue macrophages, fibrocytes, and fibroblasts. Amongst these four cell types, only peripheral blood monocytes express the combination of CD45RO, CD93, and S100A8/A9; only macrophages express the combination of CD45RO, 25F9, S100A8/A9, and PM-2K; only fibrocytes express the combination of CD45RO, 25F9, and S100A8/A9, but not PM-2K; and only fibroblasts express the combination of CD90, cellular fibronectin, hyaluronan, and TE-7. These markers are effective both in vitro and in sections from human lung. We found that markers such as CD34, CD68, and collagen do not effectively discriminate between the four cell types. In addition, IL-4, IL-12, IL-13, IFN-gamma, and SAP differentially regulate the expression of CD32, CD163, CD172a, and CD206 on both macrophages and fibrocytes. Finally, CD49c (alpha3 integrin) expression identifies a subset of fibrocytes, and this subset increases with time in culture. These results suggest that discrimination of monocytes, macrophages, fibrocytes, and fibroblasts in fibrotic lesions is possible, and this may allow for an assessment of fibrocytes in fibrotic diseases.

Systemic lupus erythematosus (SLE) is a genetically complex disease with heterogeneous clinical manifestations. Recent studies have greatly expanded the number of established SLE risk alleles, but the distribution of multiple risk alleles in cases versus controls and their relationship to subphenotypes have not been studied. We studied 22 SLE susceptibility polymorphisms with previous genome-wide evidence of association (p < 5 x 10⁻¹²⁸) in 1919 SLE cases from 9 independent Caucasian SLE case series and 4813 independent controls. The mean number of risk alleles in cases was 15.1 (SD 3.1) while the mean in controls was 13.1 (SD 2.8), with trend p = 4 x 10⁻⁸. We defined a genetic risk score (GRS) for SLE as the number of risk alleles with each weighted by the SLE risk odds ratio (OR). The OR for high-low GRS tertiles, adjusted for intra-European ancestry, sex, and parent study, was 4.4 (95% CI 3.8-5.1). We studied associations of individual SNPs and the GRS with clinical manifestations for the cases: age at diagnosis, the 11 American College of Rheumatology classification criteria, and double-stranded DNA antibody (anti-dsDNA) production. Six subphenotypes were significantly associated with the GRS, most notably anti-dsDNA (OR(high-low) = 2.36, p = 9e-9), the immunologic criterion (OR(high-low) = 2.23, p = 3e-7), and age at diagnosis (OR(high-low) = 1.45, p = 0.0060). Finally, we developed a subphenotype-specific GRS (sub-GRS) for each phenotype with more power to detect cumulative genetic associations. The sub-GRS was more strongly associated than any single SNP effect for 5 subphenotypes (the above plus hematologic disorder and oral ulcers), while single loci are more significantly associated with renal disease (HLA-DRB1, OR = 1.37, 95% CI 1.14-1.64) and arthritis (ITGAM, OR = 0.72, 95% CI 0.59-0.88). We did not observe significant associations for other subphenotypes, for individual loci or the sub-GRS. Thus our analysis categorizes SLE subphenotypes into three groups: those having cumulative, single, and no known genetic association with respect to the currently established SLE risk loci.

Scleroderma is a clinically heterogeneous disease with a complex phenotype. The disease is characterized by vascular dysfunction, tissue fibrosis, internal organ dysfunction, and immune dysfunction resulting in autoantibody production. We analyzed the genome-wide patterns of gene expression with DNA microarrays in skin biopsies from distinct scleroderma subsets including 17 patients with systemic sclerosis (SSc) with diffuse scleroderma (dSSc), 7 patients with SSc with limited scleroderma (lSSc), 3 patients with morphea, and 6 healthy controls. 61 skin biopsies were analyzed in a total of 75 microarray hybridizations. Analysis by hierarchical clustering demonstrates nearly identical patterns of gene expression in 17 out of 22 of the forearm and back skin pairs of SSc patients. Using this property of the gene expression, we selected a set of 'intrinsic' genes and analyzed the inherent data-driven groupings. Distinct patterns of gene expression separate patients with dSSc from those with lSSc and both are easily distinguished from normal controls. Our data show three distinct patient groups among the patients with dSSc and two groups among patients with lSSc. Each group can be distinguished by unique gene expression signatures indicative of proliferating cells, immune infiltrates and a fibrotic program. The intrinsic groups are statistically significant (p<0.001) and each has been mapped to clinical covariates of modified Rodnan skin score, interstitial lung disease, gastrointestinal involvement, digital ulcers, Raynaud's phenomenon and disease duration. We report a 177-gene signature that is associated with severity of skin disease in dSSc. Genome-wide gene expression profiling of skin biopsies demonstrates that the heterogeneity in scleroderma can be measured quantitatively with DNA microarrays. The diversity in gene expression demonstrates multiple distinct gene expression programs in the skin of patients with scleroderma.

MicroRNAs (miRNA) have emerged as an important new class of modulators of gene expression. In this study we investigated miRNA that are differentially expressed in lupus nephritis. Microarray technology was used to investigate differentially expressed miRNA in peripheral blood mononuclear cells (PBMCs) and Epstein-Barr Virus (EBV)-transformed cell lines obtained from lupus nephritis affected patients and unaffected controls. TaqMan-based stem-loop real-time polymerase chain reaction was used for validation. Microarray analysis of miRNA expressed in both African American (AA) and European American (EA) derived lupus nephritis samples revealed 29 and 50 differentially expressed miRNA, respectively, of 850 tested. There were 18 miRNA that were differentially expressed in both racial groups. When samples from both racial groups and different specimen types were considered, there were 5 primary miRNA that were differentially expressed. We have identified 5 miRNA; hsa-miR-371-5P, hsa-miR-423-5P, hsa-miR-638, hsa-miR-1224-3P and hsa-miR-663 that were differentially expressed in lupus nephritis across different racial groups and all specimen types tested. Hsa-miR-371-5P, hsa-miR-1224-3P and hsa-miR-423-5P, are reported here for the first time to be associated with lupus nephritis. Our work establishes EBV-transformed B cell lines as a useful model for the discovery of miRNA as biomarkers for SLE. Based on these findings, we postulate that these differentially expressed miRNA may be potential novel biomarkers for SLE as well as help elucidate pathogenic mechanisms of lupus nephritis. The investigation of miRNA profiles in SLE may lead to the discovery and development of novel methods to diagnosis, treat and prevent SLE.

Background Regulatory T cells (Tregs) are essential in the control of tolerance. Evidence implicates Tregs in human autoimmune conditions. Here we investigated their role in systemic sclerosis (SSc). Methods/Principal Findings Patients were subdivided as having limited cutaneous SSc (lcSSc, n = 20) or diffuse cutaneous SSc (dcSSc, n = 48). Further subdivision was made between early dcSSc (n = 24) and late dcSSc (n = 24) based upon the duration of disease. 26 controls were studied for comparison. CD3+ cells were isolated using FACS and subsequently studied for the expression of CD4, CD8, CD25, FoxP3, CD127, CD62L, GITR, CD69 using flow cytometry. T cell suppression assays were performed using sorted CD4CD25highCD127- and CD4CD25lowCD127high and CD3+ cells. Suppressive function was correlated with CD69 surface expression and TGFβ secretion/expression. The frequency of CD4+CD25+ and CD25highFoxP3highCD127neg T cells was highly increased in all SSc subgroups. Although the expression of CD25 and GITR was comparable between groups, expression of CD62L and CD69 was dramatically lower in SSc patients, which correlated with a diminished suppressive function. Co-incubation of Tregs from healthy donors with plasma from SSc patients fully abrogated suppressive activity. Activation of Tregs from healthy donors or SSc patients with PHA significantly up regulated CD69 expression that could be inhibited by SSc plasma. Conclusions/Significance These results indicate that soluble factors in SSc plasma inhibit Treg function specifically that is associated with altered Treg CD69 and TGFβ expression. These data suggest that a defective Treg function may underlie the immune dysfunction in systemic sclerosis.

Background Systemic sclerosis (SSc) is an autoimmune disease where controversy on Th1/Th2 balance dominates. We investigated whether the recently discovered Th17 pattern was present in SSc. Methodology and Principal Findings Patients were subdivided as having limited cutaneous SSc (lcSSc, n = 12) or diffuse cutaneous SSc (dcSSc, n = 24). A further arbitrary subdivision was made between early dcSSc (n = 11) and late dcSSc (n = 13) based upon the duration of disease. As a comparator group 14 healthy controls were studied. CD3+ cells were isolated using FACS and subsequently studied for the expression of CD4, CD8, CD25, CD45Ro, CD45Ra, IL-23, GITR, CD69 and intracellular expression of IL-17, TGFβ and IFNγ using flow cytometry. Levels of IL-17, IL-6, IL-1α and IL-23 were measured using Bioplex assays. SSc patients had more and more activated CD4+ cells. In addition, CD4, CD45Ro and CD45Ra cells from all SSc patients highly expressed the IL23R, which was associated with a higher IL-17 expression as well. In contrast, IFNγ and TGFβ were selectively up regulated in SSc subsets. In line with these observation, circulating levels of IL-17 inducing cytokines IL-6, IL-23 and IL-1α were increased in all or subsets of SSc patients. Conclusion and Significance The combination of IL-17, IFNγ and TGFβ levels in CD45Ro and CD45Ra cells from SSc patients is useful to distinguish between lSSc, ldSSc or edSSc. Blocking Th17 inducing cytokines such as IL-6 and IL-23 may provide a useful tool to intervene in the progression of SSc.

Nicotinamide phosphoribosyltransferase (NAMPT), also known as visfatin, is the rate-limiting enzyme in the salvage pathway of NAD biosynthesis from nicotinamide. Since its expression is upregulated during inflammation, NAMPT represents a novel clinical biomarker in acute lung injury, rheumatoid arthritis, and Crohn's disease. However, its role in disease progression remains unknown. We report here that NAMPT is a key player in inflammatory arthritis. Increased expression of NAMPT was confirmed in mice with collagen-induced arthritis, both in serum and in the arthritic paw. Importantly, a specific competitive inhibitor of NAMPT effectively reduced arthritis severity with comparable activity to etanercept, and decreased pro-inflammatory cytokine secretion in affected joints. Moreover, NAMPT inhibition reduced intracellular NAD concentration in inflammatory cells and circulating TNFalpha levels during endotoxemia in mice. In vitro pharmacological inhibition of NAMPT reduced the intracellular concentration of NAD and pro-inflammatory cytokine secretion by inflammatory cells. Thus, NAMPT links NAD metabolism to inflammatory cytokine secretion by leukocytes, and its inhibition might therefore have therapeutic efficacy in immune-mediated inflammatory disorders.

Sarcoidosis is a poorly understood chronic inflammatory condition. Infiltration of affected organs by lymphocytes is characteristic of sarcoidosis, however previous reports suggest that circulating lymphocyte counts are low in some patients with the disease. The goal of this study was to evaluate lymphocyte subsets in peripheral blood in a cohort of sarcoidosis patients to determine the prevalence, severity, and clinical features associated with lymphopenia in major lymphocyte subsets. Lymphocyte subsets in 28 sarcoid patients were analyzed using flow cytometry to determine the percentage of CD4, CD8, and CD19 positive cells. Greater than 50% of patients had abnormally low CD4, CD8, or CD19 counts (p<4x10(-10)). Lymphopenia was profound in some cases, and five of the patients had absolute CD4 counts below 200. CD4, CD8, and CD19 lymphocyte subset counts were significantly correlated (Spearman's rho 0.57, p = 0.0017), and 10 patients had low counts in all three subsets. Patients with severe organ system involvement including neurologic, cardiac, ocular, and advanced pulmonary disease had lower lymphocyte subset counts as a group than those patients with less severe manifestations (CD4 p = 0.0043, CD8 p = 0.026, CD19 p = 0.033). No significant relationships were observed between various medical therapies and lymphocyte counts, and lymphopenia was present in patients who were not receiving any medical therapy. Significant lymphopenia involving CD4, CD8, and CD19 positive cells was common in sarcoidosis patients and correlated with disease severity. Our findings suggest that lymphopenia relates more to disease pathology than medical treatment.

Prevalence and risk factors for respiratory symptoms and airway obstruction in HIV-infected subjects in the era of highly active antiretroviral therapy (HAART) are unknown. We evaluated respiratory symptoms and measured airway obstruction to identify the impact of HAART and other risk factors on respiratory symptoms and pulmonary function. Two hundred thirty-four HIV-infected adults without acute respiratory symptoms were recruited from an HIV clinic. All subjects were interviewed and performed spirometry. Multivariate linear and logistic regressions were performed to determine predictors of respiratory symptoms, forced expiratory volume in one second (FEV(1)) percent predicted, and FEV(1)/forced vital capacity (FEV(1)/FVC). Thirty-one percent of subjects reported at least one respiratory symptom. Smoking status (current or former versus never) (odds ratio [OR] = 2.7, 95% confidence interval [CI] = 1.41-5.22, p = 0.003), higher log plasma HIV viral levels (OR = 1.12, 95%CI = 1.02-1.24, p = 0.02), and lower FEV(1)/FVC (OR = 1.06 for every 0.01 decrease in FEV(1)/FVC, 95%CI = 1.02-1.14, p = 0.001) were independent predictors of respiratory symptoms. Age (p = 0.04), pack-year smoking history (p<0.001), previous bacterial pneumonia (p = 0.007), and HAART use (p = 0.04) were independent predictors of decreased FEV(1)/FVC. Respiratory symptoms remain common in HIV-infected subjects, especially in those with a smoking history. Subjects who were older, had a greater pack-year history of smoking, or previous bacterial pneumonia had lower FEV(1)/FVC ratios. Interestingly, use of HAART was independently associated with a decreased FEV(1)/FVC, possibly secondary to an immune response to subclinical infections, increased autoimmunity, or other factors associated with HAART use.

Systemic lupus erythematosus (SLE) is a genetically complex disease with heterogeneous clinical manifestations. A polymorphism in the STAT4 gene has recently been established as a risk factor for SLE, but the relationship with specific SLE subphenotypes has not been studied. We studied 137 SNPs in the STAT4 region genotyped in 4 independent SLE case series (total n = 1398) and 2560 healthy controls, along with clinical data for the cases. Using conditional testing, we confirmed the most significant STAT4 haplotype for SLE risk. We then studied a SNP marking this haplotype for association with specific SLE subphenotypes, including autoantibody production, nephritis, arthritis, mucocutaneous manifestations, and age at diagnosis. To prevent possible type-I errors from population stratification, we reanalyzed the data using a subset of subjects determined to be most homogeneous based on principal components analysis of genome-wide data. We confirmed that four SNPs in very high LD (r(2) = 0.94 to 0.99) were most strongly associated with SLE, and there was no compelling evidence for additional SLE risk loci in the STAT4 region. SNP rs7574865 marking this haplotype had a minor allele frequency (MAF) = 31.1% in SLE cases compared with 22.5% in controls (OR = 1.56, p = 10(-16)). This SNP was more strongly associated with SLE characterized by double-stranded DNA autoantibodies (MAF = 35.1%, OR = 1.86, p<10(-19)), nephritis (MAF = 34.3%, OR = 1.80, p<10(-11)), and age at diagnosis<30 years (MAF = 33.8%, OR = 1.77, p<10(-13)). An association with severe nephritis was even more striking (MAF = 39.2%, OR = 2.35, p<10(-4) in the homogeneous subset of subjects). In contrast, STAT4 was less strongly associated with oral ulcers, a manifestation associated with milder disease. We conclude that this common polymorphism of STAT4 contributes to the phenotypic heterogeneity of SLE, predisposing specifically to more severe disease.