Synthesis, structures, and characterization of benzildiimine complexes of rhodium(III) and iridium(I)

The reactions of trans-[(PPh₃)₂M(CO)Cl] (M = Rh and Ir) with benzildiimine (H₂BDI = 2) derived from benzil-bis(trimethylsilyl)diimine (Si₂BDI) (1) in a 1:2 and 1:1 molar ratio afforded the cationic bis-benzildiiminato complexes [Rh(PPh₃)₂(HBDI)₂]Cl (3) and the mono-benzildiimine complex [Ir(PPh₃)₂(CO)(H₂BDI)]Cl (4), respectively. Both complexes are fully characterized using IR, FAB-MS, NMR spectroscopy and elemental analysis. The single crystal X-ray structure analysis reveals a distorted octahedral coordination geometry for the Rh(III) in 3 and a highly distorted square pyramidal geometry for Ir(I) in 4. In addition, the solid-state structure of Si₂BDI is reported here for the first time showing the substituents highly twisted because of steric reasons.     

Circulating cytokines in sarcoidosis: Phenotype-specific alterations for fibrotic and non-fibrotic pulmonary disease

AimsSarcoidosis is a granulomatous disease of unknown etiology marked by tremendous clinical heterogeneity. Many patients enter remission with good long-term outcomes. Yet, chronic disease is not uncommon, and this important phenotype remains understudied. Identified alterations in local and circulating cytokines—specifically targeted for study, and often in the acute phase of disease—have informed our growing understanding of the immunopathogenesis of sarcoidosis. Our aim was to evaluate a broad panel of circulating cytokines in patients with chronic sarcoidosis. Among those with chronic disease, pulmonary fibrosis occurs in only a subset. To gain more insight into the determinants of the fibrotic response, we also determined if the phenotypes of fibrotic and non-fibrotic pulmonary sarcoidosis have distinct cytokine profiles.ResultsIn patients with sarcoidosis compared to controls, IL-5 was decreased, and IL-7 was increased. Both of these comparisons withstood rigorous statistical correction for multiple comparisons. GM-CSF met a nominal level of significance. We also detected an effect of phenotype, where IL-5 was significantly decreased in non-fibrotic compared to fibrotic pulmonary sarcoidosis, and compared to controls. Compared to controls, there was a trend towards a significant increase in IL-7 in fibrotic, but not in non-fibrotic pulmonary sarcoidosis. In contrast, compared to controls, there was a trend towards a significant increase in GM-CSF in non-fibrotic, but not in fibrotic pulmonary sarcoidosis.ConclusionsIn a comprehensive evaluation of circulating cytokines in sarcoidosis, we found IL-5, IL-7, and GM-CSF to be altered. These findings provide a window into the immunopathogenesis of sarcoidosis. IL-7 is a novel sarcoidosis cytokine and, as a master regulator of lymphocytes, is an attractive target for further studies. By observing an effect of phenotype upon cytokine patterns, we also identify specific immune alterations which may contribute to clinical heterogeneity.     

Linkage of type I interferon activity and TNF-alpha levels in serum with sarcoidosis manifestations and ancestry

Background

Both type I interferon (IFN), also known as IFN-α and tumor necrosis factor alpha (TNF-α) have been implicated in the pathogenesis of sarcoidosis. We investigated serum levels of these cytokines in a large multi-ancestral sarcoidosis population to determine correlations between cytokine levels and disease phenotypes.

Methods

We studied serum samples from 98 patients with sarcoidosis, including 71 patients of African-American ancestry and 27 patients of European-American ancestry. Serum type I IFN was measured using a sensitive reporter cell assay and serum TNF-α was measured using a commercial ELISA kit. Clinical data including presence or absence of neurologic, cardiac, and severe pulmonary manifestations of sarcoidosis were abstracted from medical records. Twenty age-matched non-autoimmune controls were also studied from each ancestral background. Differences in cytokine levels between groups were analyzed with Mann-Whitney U test, and correlations were assessed using Spearman''s rho. Multivariate logistic regression models were used to detect associations between cytokines and clinical manifestations.

Results

Significant differences in cytokine levels were observed between African- and European-American patients with sarcoidosis. In African-Americans, serum TNF-α levels were significantly higher relative to matched controls (P = 0.039), and patients with neurologic disease had significantly higher TNF-α than patients lacking this manifestation (P = 0.022). In European-Americans, serum type I IFN activity was higher in sarcoidosis cases as compared to matched controls, and patients with extra-pulmonary disease represented a high serum IFN subgroup (P = 0.0032). None of the associations observed were shared between the two ancestral groups.

Conclusions

Our data indicate that significant associations between serum levels of TNF-α and type I IFN and clinical manifestations exist in a sarcoidosis cohort that differ significantly by self-reported ancestry. In each ancestral background, the cytokine elevated in patients with sarcoidosis was also associated with a particular disease phenotype. These findings may relate to ancestral differences in the molecular pathogenesis of this heterogeneous disease.     

IgA Anti-β2-Glycoprotein I Autoantibodies Are Associated with an Increased Risk of Thromboembolic Events in Patients with Systemic Lupus Erythematosus

Background

The clinical utility of testing for antiphospholipid antibodies (aPL) of IgA isotype remains controversial.

Methodology/Principal Findings

To address this issue, we reasoned that if IgA aPL contribute to the clinical manifestations of the antiphospholipid syndrome, then an association with thromboembolic events should manifest in patients whose only aPL is of IgA isotype. We performed a retrospective chart review of 56 patients (31 with systemic lupus erythematosus [SLE] and 25 without SLE) whose only positive aPL was IgA anti-β2-glycoprotein I (isolated IgA anti-β2GPI) and compared their clinical features with 56 individually matched control patients without any aPL. Patients with isolated IgA anti-β2GPI had a significantly increased number of thromboembolic events, as compared to controls. When patients were stratified into those with and without SLE, the association between isolated IgA anti-β2GPI and thromboembolic events persisted for patients with SLE, but was lost for those without SLE. Titers of IgA anti-β2GPI were significantly higher in SLE patients who suffered a thromboembolic event. Among patients with isolated IgA anti-β2GPI, there was an increased prevalence of diseases or morbidities involving organs of mucosal immunity (i.e., gastrointestinal system, pulmonary system, and skin).

Conclusions/Significance

The presence of isolated IgA anti-β2GPI is associated with an increased risk of thromboembolic events, especially among patients with SLE. IgA anti-β2GPI is associated with an increased prevalence of morbidities involving organs of mucosal immunity.     

Peripheral Blood Gene Expression as a Novel Genomic Biomarker in Complicated Sarcoidosis

Sarcoidosis, a systemic granulomatous syndrome invariably affecting the lung, typically spontaneously remits but in ∼20% of cases progresses with severe lung dysfunction or cardiac and neurologic involvement (complicated sarcoidosis). Unfortunately, current biomarkers fail to distinguish patients with remitting (uncomplicated) sarcoidosis from other fibrotic lung disorders, and fail to identify individuals at risk for complicated sarcoidosis. We utilized genome-wide peripheral blood gene expression analysis to identify a 20-gene sarcoidosis biomarker signature distinguishing sarcoidosis (n = 39) from healthy controls (n = 35, 86% classification accuracy) and which served as a molecular signature for complicated sarcoidosis (n = 17). As aberrancies in T cell receptor (TCR) signaling, JAK-STAT (JS) signaling, and cytokine-cytokine receptor (CCR) signaling are implicated in sarcoidosis pathogenesis, a 31-gene signature comprised of T cell signaling pathway genes associated with sarcoidosis (TCR/JS/CCR) was compared to the unbiased 20-gene biomarker signature but proved inferior in prediction accuracy in distinguishing complicated from uncomplicated sarcoidosis. Additional validation strategies included significant association of single nucleotide polymorphisms (SNPs) in signature genes with sarcoidosis susceptibility and severity (unbiased signature genes - CX3CR1, FKBP1A, NOG, RBM12B, SENS3, TSHZ2; T cell/JAK-STAT pathway genes such as AKT3, CBLB, DLG1, IFNG, IL2RA, IL7R, ITK, JUN, MALT1, NFATC2, PLCG1, SPRED1). In summary, this validated peripheral blood molecular gene signature appears to be a valuable biomarker in identifying cases with sarcoidoisis and predicting risk for complicated sarcoidosis.     

Significant CD4, CD8, and CD19 Lymphopenia in Peripheral Blood of Sarcoidosis Patients Correlates with Severe Disease Manifestations

Background

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.

Methodology/Principal Findings

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<4×10⁻¹⁰). 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.

Conclusions/Significance

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.     

At the limits of the human: reading Postraciality from Palestine

ABSTRACT

Drawing from David Goldberg’s attentiveness to racism and ‘postraciality’, I read the role of racial violence and terror in the making of Palestine and the Palestinians. The paper shows how Goldberg’s book unsettles racialized convictions of postraciality, and deconstructs the uncompromising global narrative of race. Following Goldberg’s analysis, this paper challenges racialized Zionist ideologies by considering how we might understand the marking of Palestinian homes, bodies, and lives that have become sites of racialized incarceration and brutality through the process of Israeli settler colonialism. I suggest that there is a need to pay close attention to mundane, everyday modes of suffering in order to understand the postraciality of racial suffering in the context of Palestine. I explore how the equation of Palestinians with non-humans requires them either to disappear or submit to racialized exercises of power. These questions allow us to critically analyze postraciality in the context of those living at the limits of humanity.     

Statistical methodology for the analysis of dye-switch microarray experiments

Background  

In individually dye-balanced microarray designs, each biological sample is hybridized on two different slides, once with Cy3 and once with Cy5. While this strategy ensures an automatic correction of the gene-specific labelling bias, it also induces dependencies between log-ratio measurements that must be taken into account in the statistical analysis.