Project description:Atopic dermatitis (AD) is a common disease, with an increasing prevalence. The primary pathogenesis of the disease is still elusive, resulting in lack of specific treatments. The prevailing view is that AD is a biphasic, T-cell polarized disease, with Th2 predominating acute AD, and a switch to Th1 characterizing chronic disease. Identification of factors that participate in onset of lesions and maintenance of chronic lesions is critical for development of targeted therapeutics. We performed global genomic, molecular and cellular profiling of paired non-lesional, acute, and chronic skin biopsies from ten AD patients. Onset of acute lesions is associated with a striking increase in a subset of terminal differentiation proteins, specifically the IL-22-modulated S100A7-9. Correspondingly, acute disease is associated with significant increases in gene expression levels of the major Th22- (IL-22) and Th2- (IL-4, IL-31) cytokines and Th17-regulated genes (CCL20, PI3/Elafin), without significant changes in IL-17. A lesser induction of Th1- (IFNγ, MX-1, CXCL9-11) associated genes was detected in acute disease. Chronic skin lesions are characterized by significantly intensified activation of Th22, Th2 and Th1. Our data establish increased expression of S100A7-9 and other epidermal genes at onset of acute AD, with parallel activation of Th2 and Th22 cytokines. Our findings suggest an absence of switch mechanism in chronic disease and instead indicate that progression to chronic lesions is associated with intensified activation of immune axes that initiate onset of acute lesions, particularly Th22 and Th2. This alters the prevailing view of pathogenesis, with important therapeutic implications. Acute, chronic, and non-lesional skin samples were collected from ten patients with moderate-to-severe AD that met our inclusion criteria, under an institutional review board–approved protocol. The following criteria were employed to define acute AD and distinguish true acute from “acute on chronic” skin lesions: a) new lesions of <72 hours duration, as previously defined;14 b) lack of skin lichenification; c) lack of regenerative hyperplasia, as defined by epidermal thickness ≤150μ [hematoxylin and eosin (H&E)] and basal or confluent supra-basal Keratin 16 (K16) positivity. No systemic or topical treatments were allowed for ≥4 weeks prior to biopsies. Biopsy specimens were frozen in optimal cutting temperature (OCT) for immunohistochemistry (IHC) and liquid nitrogen for RNA extraction.

Project description:In psoriasis, inflammation and epidermal hyperplasia are thought to be controlled by T cell-derived cytokines. Evidence now suggests that Th17 and Th22 cells infiltrate psoriasis lesions and by secreting IL-17 and IL-22, respectively, may drive disease-specific gene or cell responses. While studies in model systems indicate that IL-22 has a dominant pathogenic role, there is evolving evidence that IL-17 contributes to features of psoriasis. To more fully understand the role of IL-17 in human disease pathogenesis, we examined psoriatic skin lesions obtained from patients treated with an anti-IL-17 (IL-17 A) monoclonal antibody, LY2439821. In a phase 1, randomized, double-blind, placebo-controlled dose escalation trial, patients with chronic psoriasis were randomized to receive 3 doses of subcutaneous LY2439821 at 5 mg (n=8), 15 mg (n=8), 50 mg (n=8), 150 mg (n=8) or placebo (n=8) at weeks 0, 2 and 4. Repeat biopsies were taken from the same lesional area at baseline, week 2 and 6. At week 6, a PASI75 was observed in 0/8, 2/8, 5/7 and 8/8 patients receiving 5 mg, 15 mg, 50 mg or 150 mg LY2439821 respectively and 0/8 patients receiving placebo. The antibody was well-tolerated. In patients receiving the two highest doses, histological and immunohistochemical analyses of biopsies revealed significant reductions from baseline in keratinocyte proliferation, hyperplasia and epidermal thickness after 2 weeks, as well as reduced infiltration into the dermis and epidermis by T-cells (CD3+) and dendritic cells (CD11c and DC-LAMP). Keratinocyte expression of innate defense proteins, S100A7, S100A8, beta-defensin2 and LL37/cathelicidin was also reduced. By week 6, the skin appeared normal with a reversal of disease defining pathological features. Quantitative RT-PCR revealed decreased expression of interferon gamma (IFN-gamma), IL-22 and IL-17, key cytokines from T cell subsets Th1, Th22 and Th17, respectively. In order to explore the extent to which IL-17 blockade influences an even broader set of inflammatory or psoriatic disease related genes, mRNA levels from skin biopsy samples were evaluated using whole genome microarrays. At week 2, the highest dose of LY2439821 modulated over 1500 genes significantly (>1.5 fold change [FC], p<0.05). Of these, 51 genes were strongly suppressed (>7-fold) including IL-19, lipocalin, amphiregulin, granzyme B, and several chemokines. In a separate analysis, those genes known to be synergistically regulated by both IL-17 and TNF-alpha showed the greatest normalization in expression compared to genes known to be regulated by TNF-alpha alone, IFN-gamma or Interferon alpha. Our data suggest that Th17 cells, through the expression of IL-17, mediate psoriasis pathogenesis, and that neutralization of IL-17 with LY2439821 suppresses signaling through multiple inflammatory circuits by inhibiting expression of cytokines from multiple T cell subsets, as well as chemokines, and antimicrobial proteins from keratinocytes. In a phase 1, randomized, double-blind, placebo-controlled dose escalation trial, patients with chronic psoriasis were randomized to receive 3 doses of subcutaneous LY2439821 at 5 mg (n=8), 15 mg (n=8), 50 mg (n=8), 150 mg (n=8) or placebo (n=8) at weeks 0, 2 and 4. Repeat biopsies were taken from the same lesional area at baseline, week 2 and 6. At week 6, a PASI75 was observed in 0/8, 2/8, 5/7 and 8/8 patients receiving 5 mg, 15 mg, 50 mg or 150 mg LY2439821 respectively and 0/8 patients receiving placebo.

Project description:In psoriasis, inflammation and epidermal hyperplasia are thought to be controlled by T cell-derived cytokines. Evidence now suggests that Th17 and Th22 cells infiltrate psoriasis lesions and by secreting IL-17 and IL-22, respectively, may drive disease-specific gene or cell responses. While studies in model systems indicate that IL-22 has a dominant pathogenic role, there is evolving evidence that IL-17 contributes to features of psoriasis. To more fully understand the role of IL-17 in human disease pathogenesis, we examined psoriatic skin lesions obtained from patients treated with an anti-IL-17 (IL-17 A) monoclonal antibody, LY2439821. In a phase 1, randomized, double-blind, placebo-controlled dose escalation trial, patients with chronic psoriasis were randomized to receive 3 doses of subcutaneous LY2439821 at 5 mg (n=8), 15 mg (n=8), 50 mg (n=8), 150 mg (n=8) or placebo (n=8) at weeks 0, 2 and 4. Repeat biopsies were taken from the same lesional area at baseline, week 2 and 6. At week 6, a PASI75 was observed in 0/8, 2/8, 5/7 and 8/8 patients receiving 5 mg, 15 mg, 50 mg or 150 mg LY2439821 respectively and 0/8 patients receiving placebo. The antibody was well-tolerated. In patients receiving the two highest doses, histological and immunohistochemical analyses of biopsies revealed significant reductions from baseline in keratinocyte proliferation, hyperplasia and epidermal thickness after 2 weeks, as well as reduced infiltration into the dermis and epidermis by T-cells (CD3+) and dendritic cells (CD11c and DC-LAMP). Keratinocyte expression of innate defense proteins, S100A7, S100A8, beta-defensin2 and LL37/cathelicidin was also reduced. By week 6, the skin appeared normal with a reversal of disease defining pathological features. Quantitative RT-PCR revealed decreased expression of interferon gamma (IFN-gamma), IL-22 and IL-17, key cytokines from T cell subsets Th1, Th22 and Th17, respectively. In order to explore the extent to which IL-17 blockade influences an even broader set of inflammatory or psoriatic disease related genes, mRNA levels from skin biopsy samples were evaluated using whole genome microarrays. At week 2, the highest dose of LY2439821 modulated over 1500 genes significantly (>1.5 fold change [FC], p<0.05). Of these, 51 genes were strongly suppressed (>7-fold) including IL-19, lipocalin, amphiregulin, granzyme B, and several chemokines. In a separate analysis, those genes known to be synergistically regulated by both IL-17 and TNF-alpha showed the greatest normalization in expression compared to genes known to be regulated by TNF-alpha alone, IFN-gamma or Interferon alpha. Our data suggest that Th17 cells, through the expression of IL-17, mediate psoriasis pathogenesis, and that neutralization of IL-17 with LY2439821 suppresses signaling through multiple inflammatory circuits by inhibiting expression of cytokines from multiple T cell subsets, as well as chemokines, and antimicrobial proteins from keratinocytes.

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Th22 cells represent a distinct human T cell subset involved in epidermal immunity and remodeling

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