A relapse of pemphigus vulgaris in pemphigus herpetiformis or a phenotypic “switch”

Sir, Pemphigus herpetiformis (PH) was originally described by Jablonska et al. in 1975. Clinically, PH presents itself as a herpetiform dermatitis with immunopathological characteristics of pemphigus [1,2]. We report an exceptional case of typical pemphigus vulgaris (PV) relapsing after 36 years in PH. A 65-year-old patient, followed for PV for 36 years and treated with corticosteroid therapy with a remission for more than thirty years, consulted for pruriginous lesions evolving for the previous eight months. A dermatological examination revealed urticariform pruriginous ring lesions surmounted by small peripheral vesicles spread throughout the body (Fig. 1), sparing the mucous membranes, and without Nikolsky’s sign. After two non-specific skin biopsies, the histological examination revealed an intraepidermal bubble with acantholytic cells and eosinophilic spongiosis (Figs. 2a and 2b). Direct immunofluorescence confirmed the diagnosis of pemphigus and indirect immunofluorescence was at the upper limit. The diagnosis of a PV relapse in PH was retained and a dapsone-based treatment was initiated at a dose of 150 mg/day and stopped seven days later when met with hemolytic anemia. Oral corticosteroid therapy involving prednisone at a dose of 1 mg/kg/day was initiated but, given the persistence of the pruritus, the decision was to combine methotrexate at a dose of 12.5 mg/week. A good evolution and a decline within eight months were observed. An improved pruritus and the disappearance of the skin lesions were achieved after one month of treatment. PV and PH are two different anatomical and clinical entities of the autoimmune disease pemphigus, with distinct clinical, histopathological, and immunopathological characteristics [1,2]. Our observation documents a complete phenotypic “switch” of pemphigus with a transition from PV to PH both clinically, histologically, and immunologically. Several rare cases of PV switching to superficial pemphigus (SP) (“phenotypic switch”) have, since 1991, been reported, with a higher frequency this direction than otherwise; the transition period varies from six months to twenty years [3]. To the best of our knowledge, no case has been described of a progression from PV to PH. Having observed one firsthand, we are first to describe the case of a complete phenotypic switch from PV to PH. The mechanism of such a transition remains poorly understood and is often observed during a relapse. Some authors suggest that the effect of immunosuppressants on the desmoglein DSG3 more marked than on DSG1 could explain the relapse of PS in PH [3,4]. Future studies on the immunological factors and predictors of PV relapses after the discontinuation of treatment would be useful to better understand the mechanisms of a relapse in pemphigus, with or without a phenotypic transition.

Long Non-coding RNA MIAT Controls Advanced Atherosclerotic Lesion Formation and Plaque Destabilization

Background: Long noncoding RNAs (lncRNAs) are important regulators of biological processes involved in vascular tissue homeostasis and disease development. The current study assessed the functional contribution of the lncRNA Myocardial Infarction Associated Transcript ( MIAT ) to atherosclerosis and carotid artery disease. Methods: We profiled differences in RNA transcript expression in patients with advanced carotid artery atherosclerotic lesions from the Biobank of Karolinska Endarterectomies (BiKE). The lncRNA MIAT was identified as the most upregulated non-coding RNA transcript in carotid plaques compared to non-atherosclerotic control arteries, which was confirmed by quantitative real time PCR (qRT-PCR) and in situ hybridization. Results: Experimental knockdown of MIAT , utilizing site-specific antisense oligonucleotides (LNA-GapmeRs) not only markedly decreased proliferation and migration rates of cultured human carotid artery smooth muscle cells (SMCs), but also increased their apoptosis. Mechanistically, MIAT regulated SMC proliferation via the EGR1-ELK1-ERK pathway. MIAT is further involved in SMC phenotypic transition to proinflammatory macrophage-like cells through binding to the promoter region of KLF4 and enhancing its transcription. Studies using Miat −/− and Miat −/− ApoE −/− mice as well as Yucatan LDLR −/− mini-pigs confirmed the regulatory role of this lncRNA in SMC de- and trans-differentiation and advanced atherosclerotic lesion formation. Conclusions: The lncRNA MIAT is a novel regulator of cellular processes in advanced atherosclerosis that controls proliferation, apoptosis, and phenotypic transition of SMCs as well as the pro-inflammatory properties of macrophages.

Transiently increased intercommunity regulation characterizes concerted cell phenotypic transition

Phenotype transition takes place in many biological processes such as differentiation and reprogramming. A fundamental question is how cells coordinate switching of expressions of clusters of genes. Through analyzing single cell RNA sequencing data in the framework of transition path theory, we studied how such a genome-wide expression program switching proceeds in three different cell transition processes. For each process we reconstructed a reaction coordinate describing the transition progression, and inferred the gene regulation network (GRN) along the reaction coordinate. In all three processes we observed common pattern that the effective number and strength of regulation between different communities increase first and then decrease. The change accompanies with similar change of the GRN frustration, defined as overall confliction between the regulation received by genes and their expression states, and GRN heterogeneity. While studies suggest that biological networks are modularized to contain perturbation effects locally, our analyses reveal a general principle that during a cell phenotypic transition intercommunity interactions increase to concertedly coordinate global gene expression reprogramming, and canalize to specific cell phenotype as Waddington visioned.