Ichthyosis with confetti caused by new and recurrent mutations in KRT10 associated with varying degrees of keratin 10 mis-localization.

BACKGROUND: Ichthyosis with confetti (IWC) is an extremely rare autosomal-dominant genodermatosis characterized by erythroderma with numerous confetti-like pale spots. IWC is caused by mutations in KRT10 (IWC-I) or KRT1 (IWC-II) which affect their tail domains. In IWC-I, the mutations lead to replacement of glycine/serine-rich keratin 10 (K10) tail with arginine- or alanine-rich frameshift motifs, causing K10 mis-localization which might trigger loss of the mutant KRT10 allele via mitotic recombination, leading to genetic reversion. OBJECTIVE: To investigate mutations in five IWC-I patients and their functional consequences. METHODS: We performed Sanger sequencing of KRT1 and KRT10 in peripheral blood samples of five patients, with highly polymorphic KRT10 SNPs genotyped to confirm loss-of-heterozygosity in the epidermis of pale spots. K10 expression pattern was examined in both patient skin biopsies and HaCaT cells overexpressing mutant KRT10-enhanced green fluorescence protein fusion. RESULTS: Four novel and one recurrent KRT10 mutations were identified in patient peripheral blood samples but not in the corresponding pale spot epidermis. Two of the mutations, c.1696_1699dupCACA and c.1676dupG, affected residues close to K10 carboxyl terminus and encoded only 3 and 6 arginine residues, which were far fewer than reported previously. Interestingly, imaging analyses for K10 in HaCaT cells overexpressing either of these two mutations and in the corresponding patients' affected skin, showed a remarkably lower level of K10 mis-localization compared to that of other mutations reported in this study. CONCLUSIONS: Our findings suggest that the number of arginine residues in the mutant tail may correlate with the level of K10 mis-localization in IWC-I keratinocytes. These results expand the genotypic and phenotypic spectrum of IWC-I.

An Autoimmune Basis for Raynaud's Phenomenon: Murine Model and Human Disease.

OBJECTIVE: Raynaud's phenomenon (RP) is common in anti-RNP-positive patients with rheumatic diseases but is not itself known to be caused by autoimmunity. The aim of this study was to assess autoantibodies that could mediate this process. METHODS: Antibodies derived from patient sera and from murine models of anti-RNP autoimmunity were screened for the ability to induce RP-like tissue ischemia and endothelial cell apoptosis in murine models and in vitro systems. RESULTS: RNP-positive sera from RP patients and murine sera from RNP-positive B cell adoptive transfer recipients induced RP-like tissue ischemia and endothelial cell apoptosis. Proteomic analysis identified cytokeratin 10 (K10) as a candidate autoantigen in RP. Monoclonal anti-K10 antibodies reproduced patterns of ischemic tissue loss and endothelial cell apoptosis; K10 knockout or depletion of anti-K10 activity in serum was protective. Cold exposure enhanced K10 expression and in vivo tissue loss. CONCLUSION: Anti-K10 antibodies are sufficient to mediate RP-like ischemia in murine models and are implicated in the pathogenesis of RP in patients with anti-RNP autoimmunity.

Identification of α1-antitrypsin as a potential prognostic biomarker for advanced nonsmall cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors by proteomic analysis.

OBJECTIVE: This retrospective study attempted to identify serum biomarkers that could help to indicate treatment response in advanced nonsmall-cell lung cancer (NSCLC) patients receiving epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment. METHODS: Two-dimensional fluorescence difference gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were used to identify proteins expressed in serum samples from NSCLC patients with long (>6-month) progression-free survival (PFS) periods, following EGFR-TKI treatment. RESULTS: Serum amyloid P component (APCS), α1-antitrypsin (AAT), fibrinogen-α (FGA), keratin type I cytoskeletal 10 (KRT10) and serotransferrin (TF) expression differed between samples taken from 18 patients before treatment (baseline) and when progressive disease (PD) was observed, during treatment. Changes in AAT, KRT10 and APCS levels were validated by Western blot analysis in the sample pool; findings were further validated by Western blot analysis in a random sample of four patients. These proteins were also present in serum samples obtained from the same patients at the partial response (PR) timepoint during EGFR-TKI treatment. AAT was upregulated at PD compared with baseline, but downregulated during the PR phase. CONCLUSION: These observations suggest that AAT could be used as a serological biomarker for predicting the utility of EGFR-TKI treatment for advanced NSCLC.