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Background: Recently, high prevalence of cryofibrinogenaemia has been observed in plasma of untreated dermatitis herpetiformis (DH) patients, and the pathological IgA and TG3 deposits in the papillary dermis were found to co-localize with fibrin and fibrinogen., Objective: To study the fibrinolytic potential in plasma of untreated, dapsone and or/gluten-free diet treated DH patients as well as the in vitro effect of dapsone on the fibrinolytic profile., Method: Plasma samples of 23 DH patients, 19 healthy subjects and 5 pemphigus vulgaris patients were investigated by a turbidimetric-clot lysis assay. Out of them 5 DH plasma samples representing different fibrinolytic parameters, and 3 healthy controls were selected for parallel fibrin clot preparation. The clot fibrin structure was examined by scanning electron microscopy (SEM), and the diameters of 900 fibrin fibres were determined in each clot., Results: A significantly prolonged clot lysis time was detected in untreated DH patients. The turbidity values of DH plasma clots indicated an altered fibrin structure that was also confirmed by SEM: significantly thicker fibrin fibers were observed in untreated, TG3 antibody positive DH patients compared to healthy controls, whereas the fiber diameters of dapsone-treated patients were similar or thinner than the control values. In line with the structural changes of fibrin, the fibrinolytic profile of 5 DH patients under dapsone treatment approached the control values., Conclusion: This study revealed that the fibrinolytic potential was impaired in the plasma of untreated DH patients, whereas dapsone corrected the fibrinolytic defect. These data suggest a pathogenic role for plasma-derived factors in the development of skin symptoms and add a new aspect to the long-known beneficial, symptomatic effect of dapsone in active DH., (Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Dermatitis herpetiformis (DH) is a chronic, polymorphic, pruritic skin disease that develops mostly in patients with latent gluten-sensitive enteropathy. DH patients usually present with skin manifestations only and are not aware of the underlying small-bowel problems. Owing to the granular immunoglobulin (Ig) A deposition at the tips of the papillary dermis and to the subepidermal blister formation associated with neutrophilic accumulations underlying the basement membrane, DH is considered to be an autoimmune blistering disease. Contrary to the other bullous disorders, DH patients have no circulating autoantibodies binding to the cutaneous basement membrane components or to other adherent structures of the skin, but they have gluten-induced IgA autoantibodies against transglutaminase (TG) 2 and TG3. The serum IgA against tissue TG2 is a most specific and sensitive serologic marker of gluten-sensitive enteropathy and is equivalent to the perviously described IgA endomysium antibodies. DH could be a cutaneous IgA-epidermal TG3 immunocomplex disease, developing only in a few patients with gluten-sensitive enteropathy as a second gluten-dependent disease. The main treatment of DH today is a strict, life-long gluten-free diet. Untreated DH patients should be regularly monitored for malabsorption and lymphomas. Associated autoimmune diseases are more common among DH patients. Family screening for gluten sensitivity is also strongly suggested., (Copyright © 2012. Published by Elsevier Inc.)

Background: Our aim was to understand why some sera from patients with a broad spectrum of autoimmune diseases or non-autoimmune diseases involving enhanced apoptosis, cell lysis and/or putative secondary autoimmune processes show reactions in the tissue transglutaminase (TGc) ELISA used for diagnosis of gluten-sensitive disease., Methods: Sera were compared from groups of patients with autoimmune diseases, diseases involving organ specific enhanced cell death, celiac disease or dermatitis herpetiformis, diseases of non-autoimmune origin, and a group without known disease. IgA antibodies against TGc were detected using human antigen (produced recombinantly in bacterial or human cells) in different systems (non-commercial ELISA with buffers of differing NaCl concentrations, and anti-TGc sandwich ELISA). Anti-gliadin and anti-endomysium antibodies were also determined., Results: Many sera from patients with autoimmune disorders gave a positive signal in the human TGc ELISAs. The signal appeared related to minor impurities in the recombinant human TGc used and to raised serum IgA antibody levels rather than to the occurrence of TGc specific antibodies in these patients., Conclusions: No association of anti-TGc Abs and autoimmune conditions independent of gluten-sensitive disease could be shown. Care should be taken to exclude copurification of chaperones, like heat shock protein 70, where preparing antigens for TGc ELISAs.

Background: Pseudoxanthoma elasticum (PXE) is an inherited systemic disorder, characterized by dermal, ocular and cardiovascular lesions. Genetic defects of the ABCC6 (MRP6) transporter are known to cause PXE., Objectives: The purpose of this study was to identify the genetic background of a PXE patient with a very early onset of the disease and severe systemic involvement., Methods: Direct sequencing of genomic DNA obtained from peripheral whole blood., Results: Our patient was found to be compound heterozygous with both ABCC6 alleles having genomic deletions. A novel exon 24-25 deletion was identified on one allele, while the frequently observed exon 23-29 deletion was found on the other allele. The novel deletion is 4.68 kb long and was shown to extend from intron 23 to 25. DNA-sequencing of a 2.03 kb fusion fragment revealed the deletion breakpoints within introns 23 and 25 originating in the middle of two Alu-repeats., Conclusion: In a patient with severe clinical symptoms, we found two genomic deletions in regions that might be important for function of the ABCC6 transporter. Genomic deletions in ABCC6 may occur more frequently in PXE patients than previously expected and future genetic analysis should focus on these mutations as well.

Dermatitis herpetiformis is characterised by granular IgA precipitates in the papillary dermis. In contrast to other autoimmune blistering diseases, where tissue-deposited and circulating autoantibodies recognise the same target within the skin, in dermatitis herpetiformis a serum IgA reacting with a component of the healthy papillary dermis has not been detected. Recently, the antigenic specificity of pathognomic skin-bound IgA has been clarified: the immune precipitates contain epidermal transglutaminase, an enzyme not previously detected in the papillary region of normal skin. Furthermore, serum IgA in dermatitis herpetiformis has been found to bind epidermal transglutaminase. These findings may relate to the fact, that dermatitis herpetiformis is associated with gluten sensitive enteropathy, coeliac disease, which is characterised by IgA type autoantibodies to a closely related enzyme, tissue transglutaminase. The two transglutaminases are highly homologous, and therefore, cross reactivity of the two antibodies might explain why patients with gluten sensitive enteropathy, with or without skin disease, generally have serum autoantibodies to both enzymes. There is growing evidence that dermatitis herpetiformis should be considered as the skin manifestation of gluten sensitivity developing in those patients with mild coeliac disease, who produce epidermal transglutaminase autoantibodies of high avidity and affinity. Both the skin and the small bowel diseases are gluten dependent and are strongly associated with HLA DQ with no genetic differences to explain the two phenotypes. The question should be asked whether the rash in dermatitis herpetiformis is a classic autoimmune blistering disease or whether it has an immune complex basis, which is the most likely alternative.

Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.

Dermatitis herpetiformis is a gluten-sensitive disease with a symmetrically distributed blistering over extensor surfaces. The association with celiac disease is further supported by the high rate of immunoglobulin A autoantibodies to endomysium in patients with dermatitis herpetiformis, which are highly specific and sensitive indicators of celiac disease. Therefore, we determined immunoglobulin A antibodies to tissue transglutaminase, the recently discovered endomysial autoantigen in celiac disease, in patients with dermatitis herpetiformis and controls. Sera of 61 patients with dermatitis herpetiformis, as characterized by granular immunoglobulin A deposits in the subepidermal basement membrane and known endomysial antibody titers (determined by indirect immunofluorescence) as well as 84 control sera of patients with dermal or intestinal diseases unrelated to dermatitis herpetiformis, were analyzed for circulating immunoglobulin A antibodies to tissue transglutaminase by enzyme-linked immunosorbent assay. Immunoglobulin A anti-tissue transglutaminase titers in patients with dermatitis herpetiformis were significantly elevated above the controls. Furthermore, the immunoglobulin A anti-tTG titers showed a positive correlation with semiquantitative endomysial antibody data. Compared with endomysial antibodies, determination of immunoglobulin A anti-tissue transglutaminase reached a specificity and sensitivity of 97.6% and 89.1%. Patients with dermatitis herpetiformis have elevated immunoglobulin A autoantibodies to tissue transglutaminase, confirming its pathogenic relation with celiac disease and further supporting the usefulness of this novel assay for screening and therapy control.

Patients with dermatitis herpetiformis (DH) have IgA deposition in the papillary dermis and in the lamina propria of the small bowel. In addition, most of DH patients' sera contain IgA class anti-reticulin antibodies, anti-endomysium antibodies (EMA), and anti-jejunal antibodies (JAB) during times of gluten intake. In previous studies, JAB and EMA seemed to be identical and related to the group of anti-reticulin antibodies. In the present study, pre-embedding en bloc immunoelectronmicroscopic methods were applied for analysis of the ultrastructural binding sites of JAB on monkey and rabbit small bowels. These substrates were incubated with sera from DH patients strongly positive for JAB. Simultaneous investigations with the PAP technique and with 5 nm gold-labeled protein A or second antibodies visualized the bound IgA identically: it was associated with collagen fibrils underlying the epithelial and cryptal basement membranes and with collagen fibrils around capillaries. Staining was also detected along the endomysial collagen fibrils of smooth muscle layers, around elastica and smooth muscle cells of blood vessel walls, and along collagen fibrils near smooth muscle cells in the lamina propria. Neither the peroxidase product nor gold deposition was detected directly on the fibers, but was associated with amorphous material surrounding collagen fibers of different diameters. The distribution of JAB-stained structures corresponded to the localization of reticulin network of the small bowel. Our data indicate that JAB recognize an antigen or antigens associated with an amorphous component of the reticulin-collagen structure of jejunum and may have identical binding sites, as anti-reticulin antibodies and EMA.

Jejunal histology and the presence of serum IgA antibodies (JAB) binding to human jejunum in vitro were studied in 139 children with severe malabsorptive symptoms. Among 33 children with confirmed coeliac disease (ESPGAN criteria), 13 (93%) of 14 sampled before starting on a gluten-free diet had JAB, none of 21 sampled had JAB while on a gluten-free diet of long duration, and 90% of 30 sampled during gluten challenge had JAB. 53 children had severe jejunal villous atrophy (probable coeliac disease): 71% of those younger than 2 years and 94% of those aged 2-18 years had JAB during gluten intake. JAB could not be detected in 53 disease control patients (normal jejunal histology) and in 3 coeliac disease patients with selective IgA deficiency. Simultaneous determination of antigliadin (AGA) and antiendomysium (EMA) levels, and gliadin and tissue absorption studies, showed that JAB and AGA are different, whereas JAB and EMA are probably identical. IgA JAB could be the target-organ-related autoantibodies in coeliac disease.

Previously we have shown by indirect immunofluorescence (IF) technique that a special IgA antibody in the sera of patients with dermatitis herpetiformis (DH) binds to the structures of the normal jejunum. Now we show by direct IF that specific IgA deposits are present in the proximal jejunum of 11/12 DH and 2/2 celiac patients before a gluten-free diet (GFD). The IgA deposition was in a tubular pattern underlying the villous and crypt epithelial basement membranes and in the lamina propria. This IgA deposition diminished or was not detectable in DH patients under a GFD for a year, and became detectable under gluten challenge in three DH patients. One patient with celiac disease and IgA deficiency, four with other intestinal diseases, and four without jejunal damage had neither jejunal IgA deposition nor circulating IgA anti-jejunal antibody. The deposition of IgA in the jejunum seemed to be correlated with the presence of IgA anti-jejunal antibody in the serum and with the presence of jejunal damage, but the degree of jejunal atrophy, the titer of the anti-jejunal antibody, and the intensity of jejunal IgA deposition in DH patient were not clearly related. Deposition of IgA in the jejunum in DH did not clearly correlate with the activity of the skin symptoms and thus may not be directly related to the pathogenesis of the skin disease of DH.

Sera of 44 children with dermatitis herpetiformis with granular IgA deposits in the papillary dermis were investigated on cryostat sections of normal jejunum of three children aged 2 months, 1 year, and 10 years by indirect immunofluorescence. Eighteen of 25 patients on a normal diet had an IgA class antibody showing the following staining patterns on substrate jejunums: tubular positivity in the lamina propria--around the crypts, beneath the villous epithelial basement membrane, and in some instances in the middle of the villous also, following the capillary system of villi; coalescence of tubular positivity at the muscularis mucosae; and positive blood vessels and smooth muscle endomysium. Eleven of 18 children with positive sera were put on a gluten-free diet (GFD) and their sera became negative. One of these 11 patients was challenged with gluten and the antibody reappeared. Nineteen patients examined only on a GFD and 30 healthy blood donors did not have this antibody. There was no strict correlation between the titer of antibody and the severity of jejunal mucosal damage.