Library

Notes: Background Pityriasis rosea (PR) is a common papulosquamous skin disorder that is suspected to have an infectious aetiology. Objectives We aimed to study the role of human herpesvirus (HHV)-7 and HHV-6 in the pathogenesis of PR. Methods We performed seroepidemiological studies (indirect immunofluorescence test) and polymerase chain reaction (PCR) analysis for HHV-6 and HHV-7 in patients with PR. Seventy-two serum samples and 37 samples of peripheral blood mononuclear cells (PBMC) from 44 patients with PR were obtained. Twenty-five patients with other skin disorders such as drug eruption, urticaria or herpes zoster were studied as controls in the PCR analysis. Results HHV-7 DNA was detected in 13 of 30 (43%) samples of PBMC of the patients with PR and 14 of 25 (56%) samples of PBMC of controls. HHV-6 DNA was detected in six of 29 (21%) patients with PR and nine of 23 (39%) controls. Thus there was no difference in the prevalence of HHV-6 or HHV-7 in PBMC between patients with PR and those with other skin disorders. In the seroepidemiological study, two cases of at least a fourfold rise in titre and five cases of a fourfold decrease in titre to HHV-7 antibody, and two cases of a fourfold rise in titre and two cases of a fourfold decrease in titre to HHV-6 antibody, were observed in 24 patients with PR. This seroepidemiological study revealed antibody responses consistent with active infection in several PR patients, but the greater proportion of the patients had no definite increase in the antibody titres. Conclusions We conclude that HHV-7 and HHV-6 may play a part in some patients with PR, but that other causative agents may exist. Further analyses are needed to determine the causative agents of PR.

Notes: In order to clarify the pathomechanism of acantholysis in Hailey–Hailey disease (HHD) and Darier’s disease (DD), the distribution of desmosomal and adherens junction-associated proteins was studied in the skin of patients with HHD (n = 4) and DD (n = 3). Domain-specific antibodies were used to determine the cellular localization of the desmosomal transmembrane glycoproteins (desmogleins 1 and 3 and desmocollin), desmosomal plaque proteins (desmoplakin, plakophilin and plakoglobin) and adherens junction-associated proteins (E-cadherin, α-catenin, β-catenin and actin). A significant difference in staining patterns between intra- and extracellular domains of desmosomal cadherins and E-cadherin was demonstrated in acantholytic cells in both HHD and DD, but not in those in pemphigus vulgaris and pemphigus foliaceus samples used as controls. In acantholytic cells in HHD and DD, antibodies against attachment plaque proteins and intracellular epitopes of desmosomal cadherins exhibited diffuse cytoplasmic staining, whereas markedly reduced staining was observed with antibodies against extracellular epitopes of the desmogleins. Similarly, membrane staining of an intracellular epitope of E-cadherin was preserved, while immunoreactivity of an extracellular epitope of E-cadherin was destroyed. While the DD gene has been identified as ATP2A2, the gene for HHD has not been clarified. The dissociation of intra- and extracellular domains of desmosomal cadherin and E-cadherin is characteristic of the acantholytic cells in HHD and DD, and not of pemphigus. This common phenomenon in HHD and DD might be closely related to the pathophysiological mechanisms in both conditions.

Notes: Background There are a number of reports of pemphigus with clinical shifting between pemphigus foliaceus (PF) and pemphigus vulgaris (PV). On the other hand, a novel enzyme-linked immunosorbent assay (ELISA) against recombinant baculoproteins of desmoglein 1 (Dsg1) (PF antigen) and Dsg3 (PV antigen) has been established and found to be extremely sensitive and specific. Objectives To characterize the change in the antibody profiles in a series of pemphigus cases with mixed features of PF and PV by various methods, including the novel ELISA. Patients/methods Sera were obtained from eight cases undergoing a shift between PF and PV and three cases of coexistent PF and PV. The autoantigens were analysed by ELISA, as well as by immunofluorescence using normal human skin sections and immunoblotting using normal human epidermal extracts. Results The results of the ELISA, immunofluorescence and immunoblotting studies showed that the transition between PF and PV correlates well with the changes of autoantibodies against either Dsg1 or Dsg3. Conclusions The clinical phenotype at each stage is defined by the anti-Dsg antibody profile in the serum of these pemphigus patients showing mixed features of PF and PV. In addition, ELISA using recombinant baculoproteins was particularly useful in distinguishing PF and PV.

Notes: Pemphigus vulgaris (PV) is an autoimmune blistering disease characterized by circulating pathogenic IgG antibodies against desmoglein 3 (Dsg3). The purpose of this study was to develop chimeric molecules for specific recognition and elimination of autoimmune B cells in PV. Mouse hybridoma cell lines producing anti-Dsg3 antibody (5H10, 12A2) were developed as an in vitro model system for targeting B cells. Dsg3-GFP, a baculoprotein containing the entire extracellular domain of Dsg3 fused with green fluorescence protein, recognized and targeted the hybridoma cells through their surface immunoglobulin receptors in an antigen-specific way. The epitopes of these monoclonal antibodies were mapped on the amino terminal EC1 and part of EC2, a region considered functionally important in cadherins. Chimeric toxin molecules containing the mapped region (Dsg3ΔN1) and modified Pseudomonas exotoxin were produced in bacteria (Dsg3ΔN1-PE40-KDEL, PE37-Dsg3ΔN1-KDEL) and tested in vitro on hybridoma cell lines. The chimeric toxins, but not Dsg3ΔN1 alone, showed dose-dependent toxic activity with a reduction in hybridoma cell number to 40–60% of toxin-negative control cultures, compared with little or no effect on anti-Dsg3-negative hybridoma cells. Furthermore, these toxins showed toxic effects on anti-Dsg3 IgG-producing B cells from Dsg3ΔN1-immunized mice, with a 60% reduction in cell number compared with Dsg3ΔN1 alone. Thus, specific recognition and targeting of antigen-specific B cells in PV was demonstrated; this strategy may hold promise as a future therapeutic option for PV and other autoimmune diseases.

Notes: We previously reported that intracolonic administration of enprostil, a prostaglandin-E2 (PGE2) analogue, had therapeutic effects on acute colitis induced in rodents by dextran sulfate sodium (DSS). In addition, production of growth-regulated gene product/cytokine-induced neutrophil chemoattractant-1 [GRO/CINC-1; an interleukin(IL)-8 like cytokine] was suppressed in the inflamed tissues. In the present study we used a human colon cancer cell line (HT-29) to investigate enprostil effects on the IL-8 production of intestinal epithelial cells stimulated by various stimulants. In a MTT assay, concentrations of enprostil 〉10−5M had cytotoxitic effects on HT-29 cells. Furthermore, 10−6 M enprostil suppressed IL-8 production in HT-29 cells, SW620 and CaCo2 stimulated with interleukin-1β (IL-1β) or lipopolysaccharide (LPS), but did not suppress this response when cells were stimulated with tumour necrosis factor (TNF)-α. These results suggest that enprostil affects a point in the pathway between the IL-1 receptor or LPS receptor and nuclear factor-κB(NF-κB), without affecting the pathway between the TNF receptor and NF-κB, with the latter factor being required for the IL-8 gene transcription. The therapeutic effect of exogenous enprostil on DSS colitis may involve the inhibition of IL-8 production in colonic epithelial cells stimulated by IL-1β or LPS.

Notes: Eosinophilic pustular folliculitis (EPF) is characterized by erythematous patches of large follicular papules and pustules involving mainly the face. Although various treatments have been attempted for EPF, including systemic and topical steroid, diaphenylsulphone, colchicine, minocycline as well as UVB phototherapy, there is no consensus on the first choice of treatment. We report a typical case and summarize 25 patients with EPF treated in our hospital between 1978 and 1998. Indomethacin was most frequently used (12/25) and showed clinical improvement in the majority of the cases (11/12). The effect of indomethacin was usually observed within 1–2 weeks after initiation of treatment. Decrease of peripheral blood eosinophils accompanied the clinical improvement. Thus, indomethacin should be considered as a first choice of treatment for EPF.

Notes: Abstract:  Adherens junctions (AJs) are cell–cell and cell–matrix junctions that are known to comprise of transmembrane and cytoplasmic components linked to the f-actin cytoskeleton. Although the presence of AJs has been confirmed in normal human epidermis, previous studies immunolocalizing AJ-related antigens have been controversial. The purpose of this study was to produce a more precise molecular mapping of AJs and their constituents in relation to desmosomes in normal human epidermal keratinocytes. Using an electron microscopy (EM) method to optimally fix plasma membranes, AJ structures were typically seen as a narrowing of the intercellular space between two keratinocytes that was distinct from desmosomes and gap junctions. Such structures were consistently found more frequently in the upper epidermis than in the basal layer. Immunogold electron microscopy showed an absence of the AJ components (E-cadherin and β-catenin) from desmosomal areas but they were present at interdesmosomal areas at sites of close membrane association. Conversely, the desmosomal components plakoglobin and plakophilin 1 were restricted only to the outer attachment plaque of the desmosome. These results further confirm that AJs have a distinct molecular composition and distribution from desmosomes and that they regularly occur between desmosomes along the keratinocyte plasma membrane to provide alternative cell–cell adhesion mechanisms.

Notes: Summary Background Pemphigus is an antidesmoglein (Dsg) autoimmune disease that is divided into two major subtypes: pemphigus foliaceus (PF) and pemphigus vulgaris (PV). We previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 to detect IgG autoantibodies in patients with pemphigus. The protocol for the ELISAs was optimized for serological diagnosis, but under the conditions used, these assays were not particularly useful for monitoring disease activity in certain patients. That is, the sera from some patients with high-titre antibodies continued to show high index values in the ELISA after clinical improvement. Objectives In the study reported here, we modified the ELISA protocol to obtain ‘true’ index values that exhibit a better correlation with disease activity. Methods We tested two cases of pemphigus foliaceus (PF) and four cases of pemphigus vulgaris (PV), each with ELISA index values greater than 150 for Dsg1 or Dsg3. We ran an ELISA with sera from these patients serially diluted from 1 : 100 to 1 : 12,800. We then performed ELISA with a series of PV No. 1 sera diluted to 1 : 800 and PV No. 2–4 and PF No. 1–2 sera diluted to 1 : 1600, after which we plotted the ELISA index values against the time course of disease activity. Results In each of these cases, there was no apparent decline, over the course of the disease activity, in the ELISA index values at a serum dilution of 1 : 100, probably because the antigen–antibody reaction was saturated at that dilution. After running an ELISA with sera serially diluted from 1 : 100 to 1 : 12,800 we found that a linear dose-dependency between the dilution value and the index value was only observed when sera were diluted to 1 : 800 or more in one case (PV No.1) and to 1 : 1600 or more in the other five cases (PV No. 2–4, PF No. 1–2). After performing ELISA with these series as outlined above we plotted the ELISA index values against the time course of disease activity and found that the index values obtained from these appropriately diluted sera fluctuated in parallel with disease activity, and declined with clinical improvement. Conclusions These findings indicate that when appropriate dilutions are used in Dsg1 and Dsg3 ELISA, these assays can provide useful serological information for assessing disease activity in PF and PV.

Notes: We report a 73-year-old Japanese female who developed IgG autoantibodies against BP180 as well as desmoglein 3 (Dsg3). She showed tense blisters on the extremities without apparent mucosal involvement and a skin biopsy indicated subepidermal blisters with eosinophilic spongiosis. Her clinical and histologic features indicated the diagnosis of bullous pemphigoid while anti-Dsg3 IgG might not show an apparent pathogenic effect. Interestingly, titres of anti-Dsg3 IgG fluctuated in parallel with those of anti-BP180 IgG throughout the course with two flares. Although the exact mechanism for autoantibody production is still unknown, the close link in the production of IgG autoantibodies against two independent skin antigens suggests a shared immunoregulatory mechanism against cutaneous autoantigens.