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Epidermolysis bullosa (EB) is a chronic inheritable disease that leads to severe blistering and fibrosis. Previous studies have shown that the actin cytoskeletal protein flightless I (Flii) impairs wound healing associated with EB. Using a mouse model of EB acquisita (EBA), the effect of "mopping up" Flii using Flii-neutralizing antibodies (FnAbs) before, during, and after blister formation was determined. FnAbs, incorporated into a cream vehicle and applied topically to the skin, penetrated into the basal epidermis and upper papillary dermis but were not detected in serum or other organs and did not alter neutrophil or macrophage infiltration into the blistered skin. Histological assessment of blister severity showed that treatment of early-stage blisters with FnAb cream reduced their severity and improved their rate of healing. Treatment of established blisters with FnAb cream also improved healing and restored the skin's tensile strength toward that of normal skin. Repeated application of FnAbs to EBA skin before the onset of blistering reduced the severity of skin blistering. Independent of when the FnAbs were applied, skin barrier function and wound healing were improved and skin fragility was reduced, suggesting that FnAbs could potentially improve healing of patients with EB. Refereed/Peer-reviewed

The International Pre IID 2013 Satellite Meeting on Autoimmune Bullous Diseases (AIBDs) was held in Lubeck, Germany, from 6th to 7th May 2013, preceding the International Investigative Dermatology (IID) meeting in Edinburgh, UK. This Satellite Meeting followed the tradition of the IID-associated symposia on AIBDs in Kyoto (1993), Salzburg (1998), and Otsu (2008). In total, 180 international researchers and clinicians attended the meeting. Plenary lectures covered the following topics: (i) epidemiology and genetics of AIBDs; (ii) diagnosis and novel disease entities; (iii) cell biology of desmosomes and disease pathways; (iv) cell biology of hemidesmosomes and disease pathways; and (v) outcome measures and novel treatments. In the exhibit of posters, approximately 60 abstracts were presented. The meeting was flanked by two satellite symposia. Importantly, the meeting provided ample time for interactive discussions, critical analyses of the progress achieved to date, and the identification of questions that still needed to be resolved.

Epidermolysis bullosa simplex is a heterogeneous group of inherited bullous disorders due to mutations in keratins 5 and 14. We report two different mutations in keratin 14 at codon 119 of the helix initiation peptide, each with different phenotypic expression. One, a sporadic case that clinically resembles Dowling-Meara epidermolysis bullosa simplex, resulted from conversion of methionine to threonine (M119T). The other, a multigeneration family with the Koebner phenotype, resulted from a previously unreported methionine to valine substitution (M119V). We suggest that loss of hydrophobicity during conversion of methionine to threonine is responsible for the more severe presentation of the first family, whereas maintenance of the hydrophobic nature of the amino acid with conversion to valine resulted in a less severe variant of epidermolysis bullosa simplex. Although most prior mutations in the highly conserved boundary motif of the alpha-helix have resulted in the Dowling-Meara subtype, our findings confirm that it is not always possible to predict the epidermolysis bullosa simplex severity on the basis of the location of the mutation along the keratin polypeptide. The specific amino acid substitution may be more critical in some cases.

TO THE EDITOR Recessive dystrophic epidermolysis bullosa (RDEB) is a devastating inherited skin disease caused by mutations in the gene encoding type VII collagen (Christiano et al., 1993). The condition is characterized by skin fragility, trauma-induced skin blistering and chronic non-healing wounds (Mellerio et al., 2007). Patients with RDEB are at strongly increased risk of developing aggressive cutaneous squamous cell carcinoma (SCC) which is the cause of death by age 45 years in 70% of individuals with the most severe form of RDEB (Fine et al., 2009). Potential similarities between the microenvironment of non-healing wounds and mucosal epithelia where human papillomaviruses (HPV) have been shown to induce the development of SCC (Zur Hausen, 2009) led us to investigate whether HPV infection could be responsible for the increased incidence and aggressive nature of RDEB SCC. The involvement of HPV in the development of cutaneous SCC remains controversial except in the rare genodermatosis epidermodysplasia verruciformis (EV) where up to 60% of patients develop SCC containing high copy numbers of beta-PV (β-PV) (Harwood and Proby, 2002) which_may be restricted to a minority of tumor cells (Dell’Oste et al., 2009). The possibility that HPV are also involved in RDEB SCC has not been addressed. HPV are a diverse group of small double-stranded DNA viruses that infect squamous epithelial cells. The two largest genera are alpha-PV (α-PV), comprising all HPV genotypes found in mucosal lesions as well as many of those associated with benign skin warts, and β-PV, containing HPV types which have most frequently been associated with EV and cutaneous SCC (de Villiers et al., 2004). Because vaccines against prevalent high risk mucosal/genital HPV (HPV16/18) are available and effective at preventing cancer development (Zur Hausen, 2009), we tested RDEB SCC for the presence of 18 high risk α-PV types using the digene HPV genotyping reverse hybridization assay (RHA) detection kit (Qiagen, Leiden, The Netherlands). We tested DNA prepared from 21 separate SCC isolated from 12 RDEB patients as well as DNA from 39 organ transplant recipient (OTR) SCC and 18 immunocompetent (ICP) SCC collected for a separate study (Purdie et al., 2009) with 6 vulval SCC samples included as positive controls. All DNA were isolated from frozen tissue collected after informed consent and in accordance with Helsinki guidelines following research ethics committee approval. All cutaneous SCC from RDEB and non-RDEB individuals were negative, whereas 9 different α -PV types were detected in the vulval SCC samples. Next we tested the presence of beta-PV using the RHA kit skin (β) HPV detection system (Diassay, Rijswijk, The Netherlands) (de Koning et al., 2006). In addition to the cutaneous SCC samples described we tested 7 peri-tumoral skin samples from 5 of our SCC RDEB patients and normal uninvolved skin from 11 RDEB patients who had not yet developed SCC. As before, all DNA were isolated from frozen tissue. Data are summarized in Table 1. The overall detection rate of β-PV in RDEB SCC was 90% compared with 74% and 78% for OTR SCC and ICP SCC respectively, with similar frequencies observed in RDEB peri-tumoral and normal skin. As β-PV infection has been shown to be prevalent at low copy number in non-tumour bearing normal skin and hair follicles, a role for these viruses is perhaps more plausible in lesions with higher viral load (Feltkamp et al., 2008). We next examined viral load for β-PV using quantitative PCR (Q-PCR) as described (Weissenborn et al., 2010), with input cell equivalents determined by normalization to β-globin. HPV β types were chosen for investigation on the basis of their frequent detection in at least 2 of the 3 groups of SCC samples (Table 1). Data are summarized in Table 2. Only 25-38% of the RHA-positive SCC samples analyzed were above the detection threshold for Q-PCR, suggesting that the initial RHA detection method was extremely sensitive. The Q-PCR detection efficiency in RDEB SCC was not significantly different from that reported in a previous study of predominantly ICP SCC (Weissenborn et al., 2005) where 46% of samples showed detectable β-PV viral load (p=0.248, Fisher’s exact test). Furthermore, the relative viral load in the two studies were very similar, with all SCC showing comparatively low overall HPV-DNA copy numbers of less than one per five cell equivalents. It must be emphasized however that these data do not exclude the possibility of a considerably higher viral load in a subset of tumor cells, as recently demonstrated for EV SCC (Dell’Oste et al., 2009). With the exception of 2 HPV8-positive samples where viral load were comparable, the RDEB peri-tumoral and normal skin samples examined were below the Q-PCR detection threshold. These combined data imply that high copy number HPV infection is not a general feature of RDEB skin, despite its unique microenvironment. In particular, RDEB SCC does not appear significantly different from other cutaneous SCC in overall prevalence of HPV infection or viral load. Table 1 Percentage samples positive for β-HPV by reverse hybridization assay with multiple infection indicated. Table 2 Analysis of viral load for HPV types 5, 8, 15, 23 and 24 in each sample group. To our knowledge the possible contribution of HPV infection to RDEB-SCC pathogenesis is previously unreported. Although our numbers are small, 21 cases of RDEB SCC is a significant series for this rare disease and compares favorably with other examples of analysis in this tumor group (23 RDEB SCC examined for p53 immuno-staining (Slater et al., 1992) and 25 RDEB SCC analyzed for matrix metalloproteinase (MMP) immuno-staining (Kivisaari et al., 2008) for example. The use of highly sensitive PCR methodology to detect relatively ubiquitous viral DNA sequences together with confounding factors such as type of tissue analysed have yielded conflicting data on HPV prevalence in OTR versus ICP individuals, actinic keratosis versus SCC, and normal skin (Harwood and Proby, 2002; Weissenborn et al., 2005; Feltkamp et al., 2008; Mackintosh et al., 2009). Nevertheless, combined viral load data have shown that in contrast to α-PV and cervical cancer, β-PV presence is not necessary in each tumor cell for maintenance of the malignant phenotype, although this does not preclude a role for HPV in cutaneous SCC. Our results from RDEB SCC lie within the range of other cutaneous SCC data and show no evidence of HPV contribution to the increased incidence and aggressive nature of RDEB SCC.

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease caused by anti-epithelial antibodies, leading to disruption of cell–cell adhesion. Although the disease is exceedingly rare worldwide, it is known to be relatively prevalent in Jewish populations. The low prevalence of the disease represents a significant obstacle to a genome-wide approach to the mapping of susceptibility genes. We reasoned that the study of a genetically homogeneous cohort characterized by a high prevalence of PV may help exposing associated signals while reducing spurious results due to population sub-structure. We performed a genome-wide association study using 300K single-nucleotide polymorphisms (SNPs) in a case–control study of 100 PV patients of Jewish descent and 397 matched control individuals, followed by replication of significantly associated SNPs in three additional cohorts of Jewish, Egyptian, and German origin. In addition to the major histocompatibility complex locus, a genomic segment on 8q11.23 that spans the ST18 gene was also found to be significantly associated with PV. This association was confirmed in the Jewish and Egyptian replication sets but not in the German sample, suggesting that ST18-associated variants may predispose to PV in a population-specific manner. ST18 regulates apoptosis and inflammation, two processes of direct relevance to the pathogenesis of PV. Further supporting the relevance of ST18 to PV, we found this gene to be overexpressed in the skin of PV patients as compared with healthy individuals.