Intrinsic atopic dermatitis shows similar T(H)2 and higher T(H)17 immune activation compared with extrinsic atopic dermatitis
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
Authors: Suarez-Farinas, Mayte; Dhingra, Nikhil; Gittler, Julia; Shemer, Avner; Cardinale, Irma; Strong, Cristina de Guzman; Krueger, James G.; Guttman-Yassky, Emma
Abstract
Background: Atopic dermatitis (AD) is classified as extrinsic and intrinsic, representing approximately 80% and 20% of patients with the disease, respectively. Although sharing a similar clinical phenotype, only extrinsic AD is characterized by high serum IgE levels. Because most patients with AD exhibit high IgE levels, an "allergic"/IgE-mediated disease pathogenesis was hypothesized. However, current models associate AD with T-cell activation, particularly TH2/TH22 polarization, and epidermal barrier defects. Objective: We sought to define whether both variants share a common pathogenesis. Methods: We stratified 51 patients with severe AD into extrinsic AD (n 5 42) and intrinsic AD (n 5 9) groups (with similar mean disease activity/SCORAD scores) and analyzed the molecular and cellular skin pathology of lesional and nonlesional intrinsic AD and extrinsic AD by using gene expression (real-time PCR) and immunohistochemistry. Results: A significant correlation between IgE levels and SCORAD scores (r = 0.76, P < 10(-5)) was found only in patients with extrinsic AD. Marked infiltrates of T cells and dendritic cells and corresponding epidermal alterations (keratin 16, Mki67, and S100A7/A8/A9) defined lesional skin of patients with both variants. However, higher activation of all inflammatory axes (including T(H)2) was detected in patients with intrinsic AD, particularly T(H)17 and T(H)22 cytokines. Positive correlations between T(H)17-related molecules and SCORAD scores were only found in patients with intrinsic AD, whereas only patients with extrinsic AD showed positive correlations between SCORAD scores and (T)H2 cytokine (IL-4 and IL-5) levels and negative correlations with differentiation products (loricrin and periplakin). Conclusions: Although differences in T(H)17 and T(H)22 activation exist between patients with intrinsic AD and those with extrinsic AD, we identified common disease-defining features of T-cell activation, production of polarized cytokines, and keratinocyte responses to immune products. Our data indicate that a T(H)2 bias is not the sole cause of high IgE levels in patients with extrinsic AD, with important implications for similar therapeutic interventions.
In-Frame Indel Mutations in theGenome of the Blind Mexican Cavefish, Astyanax mexicanus
GENOME BIOLOGY AND EVOLUTION
Authors: Berning, Daniel; Adams, Hannah; Luc, Heidi; Gross, Joshua B.
Abstract
Organisms living in the subterranean biome evolve extreme characteristics including vision loss and sensory expansion. Despite prior work linking certain genes toMendelian traits, the genetic basis for complex cave-associated traits remains unknown. Moreover, it is unclear if certain forms of genetic variation (e.g., indels, copy number variants) aremore common in regressive evolution. Progress in this area has been limited by a lack of suitable natural model systems and genomic resources. In recent years, the Mexican tetra, Astyanax mexicanus, has advanced as a model for cave biology and regressive evolution. Here, we present the results of a genome-wide screen for in-frame indels using alignments of RNA-sequencing reads to the draft cavefish genome. Mutations were discovered in three genes associated with blood physiology (mlf1, plg, and wdr1), two genes associated with growth factor signaling (ghrb, rnf126), one gene linked to collagen defects (mia3), and one gene which may have a global epigenetic impact on gene expression (mki67). With one exception, polymorphisms were shared between Pachon and Tinaja cavefish lineages, and different from the surface-dwelling lineage. We confirmed the presence of mutations using direct Sanger sequencing and discovered remarkably similar developmental expression in both morphs despite substantial coding sequence alterations. Further, three mutated genes mapped near previously established quantitative trait loci associated with jaw size, condition factor, lens size, and neuromast variation. This work reveals previously unappreciated traits evolving in this species under environmental pressures (e.g., blood physiology) and provides insight to genetic changes underlying convergence of organisms evolving in complete darkness.