Dimethyl fumarate modulates the Treg-Th17 cell axis in patients with psoriasis.

BACKGROUND: Dimethyl fumarate (DMF) is the active ingredient of Skilarence™ and Tecfidera™, which are used for the treatment of psoriasis and multiple sclerosis, respectively. Various immunomodulatory mechanisms of action have been identified for DMF; however, it is still unclear what effects DMF exerts in vivo in patients with psoriasis. OBJECTIVES: In this study we examined the effects of DMF, both in vivo and in vitro, on T cells, which play a key role in the pathogenesis of psoriasis. METHODS: The frequency of T-cell subsets was examined by flow cytometry in untreated patients with psoriasis or those treated with DMF. The effects of DMF in vitro on T-cell survival, activation and proliferation, and cell-surface thiols were assessed by flow cytometry. RESULTS: In patients with psoriasis treated with DMF we observed an increase in the frequency of T regulatory (Treg) cells and a decrease in T helper (Th)17 lineage cells and the associated cytokines interleukin-17, interleukin-22 and granulocyte-macrophage colony-stimulating factor. T cells cultured in vitro with DMF exhibited reduced viability, and inhibition of activation and proliferation in response to stimulation due to the oxidative effects of DMF. However, the frequency of Treg cells increased in the presence of DMF due to their heightened ability to resist DMF-induced oxidative stress. CONCLUSIONS: DMF enhanced the ratio of Treg cells to Th17 cells in patients with psoriasis, in patients with multiple sclerosis and in vitro. Furthermore, our data suggest that this is at least in part as a result of the differential effects of DMF on Treg cells compared with conventional T cells.

The pathogenic role of dendritic cells in non-infectious anterior uveitis.

BACKGROUND: Anterior uveitis (AU) is characterised by infiltration of immune cells into the anterior chamber of the eye. Dendritic cells (DC) are professional antigen presenting cells that initiate and promote inflammation. This study aims to characterise DC in AU and to examine the effects of aqueous humor (AqH) on DC maturation and function. METHODS: The frequency and phenotype of AU and healthy control (HC) circulating DC was examined. AU and HC AqH was immunostained and assessed by flow cytometry. The effect of AU and HC AqH on DC activation and maturation was examined and subsequent effects on CD4+ T cell proliferation assessed. RESULTS: AU peripheral blood demonstrated decreased circulating myeloid and plasmacytoid DC. Within AU AqH, three populations of CD45+ cells were significantly enriched compared to HC; DCs (CD11c+ HLA-DR+), neutrophils (CD15+ CD11c+) and T cells (CD4+ and CD8+). A significant increase in IFNγ, IL8 and IL6 was observed in the AU AqH, which was also significantly higher than that of paired serum. AU AqH induced expression of CD40 and CD80 on DC, which resulted in increased T cell proliferation and the production of GM-CSF, IFNγ and TNFα. CONCLUSION: DC are enriched at the site of inflammation in AU. Our data demonstrate an increase in inflammatory mediators in the AU inflamed microenvironment. AU AqH can activate DC, leading to subsequent proliferation and activation of effector T cells. Thus, the AU microenvironment contributes to immune cell responses and intraocular inflammation.

Natural killer cells from psoriasis vulgaris patients have reduced levels of cytotoxicity associated degranulation and cytokine production.

Psoriasis vulgaris is a chronic inflammatory disease of the skin with a strong genetic component and immune system involvement. Although some evidence suggests that Natural Killer (NK) cells may play a part in psoriasis, their role is relatively unstudied and results are controversial. In this current study, NK cells from psoriasis patients exhibited reduced degranulation and produced lower levels of the pro-inflammatory cytokines IFN-γ and TNF-α. Further investigation found that NK cells from psoriasis patients and healthy controls expressed similar levels of activation markers, NK cell receptors and apoptosis-inducing molecules. In addition, comparable levels of several cytokines important in NK cell biology were found in the serum of psoriasis patients and healthy controls. Genotyping analysis revealed that HLA-C2, which provides a ligand for killer-cell immunoglobulin-like receptors (KIR) expressed by NK cells, was strongly associated with psoriasis susceptibility. However, no link between the KIR genes themselves and disease was found.

Dysregulated cytokine expression in lesional and nonlesional skin in hidradenitis suppurativa.

BACKGROUND: There is a dearth of information on the precise pathogenesis of hidradenitis suppurativa (HS), but immune dysregulation is implicated. OBJECTIVES: To determine the nature of the immune response in HS. METHODS: Skin biopsies - lesional, perilesional (2 cm away) and uninvolved (10 cm away) - were obtained from patients with HS and healthy controls. The expression of various cytokines was determined by enzyme-linked immunosorbent assay, flow cytometry and real-time polymerase chain reaction. RESULTS: The expression of the inflammatory cytokines interleukin (IL)-17, IL-1ß and tumour necrosis factor-α was enhanced in lesional skin of patients with HS. In addition, IL17A and IL1B mRNA were enhanced in clinically normal perilesional skin. CD4(+) T cells produced IL-17 in HS, while CD11c(+) CD1a(-) CD14(+) cells were sources of IL-1ß. Activated caspase-1 was detected in HS skin and was associated with enhanced expression of NLRP3 and IL18. Inhibition of caspase-1 decreased IL-1ß and IL-18 production, suggesting that the caspase-1 pathway participates in IL-1ß and IL-18 expression in HS. Abnormal cytokine expression was detected in perilesional and uninvolved skin, which may suggest that subclinical inflammation is present in HS skin prior to the formation of an active lesion. CONCLUSIONS: This study demonstrates that CD4(+) T cells produce IL-17 in HS and that the IL-17 pathway may be important in HS pathogenesis. CD11c(+) CD1a(-) CD14(+) cells are a source of IL-1ß in HS, the production of which was shown to be mediated, in part, via a caspase-1-dependent pathway. These results suggest that IL-17 and the caspase-1-associated cytokines IL-1ß and IL-18 may play a role in the pathogenesis of HS.

Billion-pixel x-ray camera (BiPC-X).

The continuing improvement in quantum efficiency (above 90% for single visible photons), reduction in noise (below 1 electron per pixel), and shrink in pixel pitch (less than 1 µm) enable billion-pixel x-ray cameras (BiPC-X) based on commercial complementary metal-oxide-semiconductor (CMOS) imaging sensors. We describe BiPC-X designs and prototype construction based on flexible tiling of commercial CMOS imaging sensors with millions of pixels. Device models are given for direct detection of low energy x rays (<10 keV) and indirect detection of higher energies using scintillators. Modified Birks's law is proposed for light yield non-proportionality in scintillators as a function of x-ray energy. Single x-ray sensitivity and spatial resolution have been validated experimentally using a laboratory x-ray source and the Argonne Advanced Photon Source. Possible applications include wide field-of-view or large x-ray aperture measurements in high-temperature plasmas, the state-of-the-art synchrotron, x-ray free electron laser, and pulsed power facilities.

T cells in multiple sclerosis and experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a demyelinating inflammatory disorder of the central nervous system (CNS), which involves autoimmune responses to myelin antigens. Studies in experimental autoimmune encephalomyelitis (EAE), an animal model for MS, have provided convincing evidence that T cells specific for self-antigens mediate pathology in these diseases. Until recently, T helper type 1 (Th1) cells were thought to be the main effector T cells responsible for the autoimmune inflammation. However more recent studies have highlighted an important pathogenic role for CD4(+) T cells that secrete interleukin (IL)-17, termed Th17, but also IL-17-secreting γδ T cells in EAE as well as other autoimmune and chronic inflammatory conditions. This has prompted intensive study of the induction, function and regulation of IL-17-producing T cells in MS and EAE. In this paper, we review the contribution of Th1, Th17, γδ, CD8(+) and regulatory T cells as well as the possible development of new therapeutic approaches for MS based on manipulating these T cell subtypes.