Pemphigus vulgaris (PV) is a potentially fatal blistering disease caused by autoantibodies against desmoglein 3 (Dsg3). Here, we clone anti-Dsg3 antibodies from four PV patients and identify pathogenic VH1-46 autoantibodies from all four patients. Unexpectedly, VH1-46 autoantibodies had relatively few replacement mutations. We reverted antibody somatic mutations to their germline sequences to determine the requirement of mutations for autoreactivity. Three of five VH1-46 germline-reverted antibodies maintain Dsg3 binding, compared to zero of five non-VH1-46 germline-reverted antibodies. Site-directed mutagenesis of VH1-46 antibodies demonstrate that acidic amino acid residues introduced by somatic mutation or heavy chain VDJ recombination are necessary and sufficient for Dsg3 binding. Our data suggest that VH1-46 autoantibody gene usage is commonly found in PV because VH1-46 antibodies require few to no mutations to acquire Dsg3 autoreactivity, which may favor their early selection. Common VH gene usage indicates common humoral immune responses, even among unrelated patients.

Pemphigus vulgaris is a blistering disease associated with autoantibodies to the desmosomal adhesion protein, desmoglein 3. Genetic deficiency of desmoglein 3 in mice mimics autoimmunity to desmoglein 3 in pemphigus vulgaris, with mucosal-dominant blistering in the suprabasal layer of the epidermis. Mice with an epidermal-specific deletion of desmocollin 3, the other major desmosomal cadherin isoform expressed in the basal epidermis, develop suprabasal blisters in skin that are histologically identical to those observed in pemphigus vulgaris, suggesting that desmocollin 3 might be a target of autoantibodies in some pemphigus vulgaris patients. We now demonstrate that desmocollin 3 is an autoantigen in pemphigus vulgaris, illustrated in a patient with mucosaldominant blistering. Six of 38 pemphigus vulgaris and one of 85 normal serum samples immunoprecipitate desmocollin 3 (P ‫؍‬ 0.003). Incubation of patient IgG with human keratinocytes causes loss of intercellular adhesion, and adsorption with recombinant desmocollin 3 specifically prevents this pathogenic effect. Additionally, anti-desmocollin 3 sera cause loss of keratinocyte cell surface desmocollin 3, but not desmoglein 3 by immunofluorescence , indicating distinct cellular pathogenic effects in anti-desmocollin and antidesmoglein pemphigus , despite their identical clinical presentations. These data demonstrate that desmocollin 3 is a pathogenic autoantigen in pemphigus vulgaris and suggest that pemphigus vulgaris is a histological reaction pattern that may result from autoimmunity to desmoglein 3, desmocol-

This article provides a systematic evaluation of the scientific evidence of the efficacy of oral antibiotics for acne. Due to heterogeneity in the design of the trials, there is insufficient evidence to support one type, dose, or duration of oral antibiotic over another in terms of efficacy; however, due to increasing resistance to antibiotics, dermatologists should heed consensus guidelines for their appropriate use.

Summary Background Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are potentially fatal blistering diseases caused by autoantibodies targeting desmoglein (Dsg) adhesion proteins. Previous studies have shown an IgG4 > IgG1 predominance of anti-Dsg antibodies in pemphigus; however, no studies have examined total serum IgG4 levels in pemphigus. IgG4 is induced by chronic antigen stimulation, which could occur with persistent skin blistering and potentially elevate the total serum IgG4 relative to other IgG subclasses in patients with pemphigus. Objectives The primary aim of the study was to quantitate total and Dsg-specific IgG subclasses in patients with pemphigus. Methods IgG subclasses and Dsg-specific IgG1 and IgG4 were quantitated in patients with PV and PF, and in sera from age-matched controls using a subclass enzyme-linked immunosorbent assay. The effectiveness of IgG4 depletion in blocking IgG pathogenicity in PV was determined using a keratinocyte dissociation assay. Results Dsg-specific antibodies comprised a median of 7·1% and 4·2% of total IgG4 in patients with PV and PF, respectively, with eightfold and fourfold enrichment in IgG4 vs. IgG1. Total serum IgG4, but not other IgG subclasses, was enriched in patients with PV and PF compared with age-matched controls (P = 0·004 and P = 0·005, respectively). IgG4 depletion of PV sera reduced pathogenicity in a keratinocyte dissociation assay and showed that affinity-purified IgG4 is more pathogenic than other serum IgG fractions. Conclusions Dsg-specific autoantibodies are significantly enriched in IgG4, which may explain the enrichment of total serum IgG4 in some patients with pemphigus. By preferentially targeting autoimmune rather than beneficial immune antibodies, IgG4-targeted therapies may offer safer treatment options for pemphigus.

The utility of laser therapy is increasingly being recognized in the treatment of active acne vulgaris. We aimed to perform a narrative review of the medical literature on the use of laser therapy for the treatment of active acne vulgaris. We performed a PubMed literature search on September 1, 2016 using the search terms "active acne," "acne," "laser therapy," and "laser surgery." Case reports, case series, cohort, and controlled trials were included. Studies of lasers in the treatment of acne, including erbium glass, Nd:YAG, pulse dye laser (PDL), potassium titanyl phosphate (KTP) laser, and laser-based photodynamic therapy, have been published. While treatment of active acne with lasers has been successful, many studies are limited by small patient number and lack of control populations and comparison to standard therapies for active acne. Laser therapies are increasingly becoming part of or an adjunct to the medical treatment of active acne and are a useful treatment modality.