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Notizen: Paraneoplastic pemphigus is a relatively recently described immunobullous disease with characteristic features. We report three cases of paraneoplastic pemphigus in adult men with chronic lymphocytic leukaemia arising within a week of completion of treatment with fludarabine. In all cases, withdrawal of fludarabine and treatment of the blistering was associated with marked cutaneous improvement. Fludarabine, a synthetic nucleoside analogue, which has only been available in Britain since 1994, is known to be associated with autoimmune phenomena and may have been involved in the development of paraneoplastic pemphigus in these cases.

Notizen: 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.

Notizen: 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.

Notizen: The localization of DNA replicating cells, epidermal growth factor (EGF) receptor-expressing cells and ras oncogene product p21 (p-21ras) positive cells were examined in various skin tumours to elucidate the role of EGF receptor and p21ras in the epidermis. Normal skin, keratoacanthoma (KA), solar keratosis (SK), Bowen's disease (BD), squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and extramammary Paget's disease (PD) were studied. EGF receptors were seen in proliferating layers, where DNA replicating cells localize, but p21ras was found in the more differentiated layers. We conclude that EGF receptor expression is closely associated with cellular proliferation, but p21ras may play a role in the differentiation of cells in various skin tumours.

Notizen: We have examined the localization of DNA replicating cells and EGF receptor-expressing cells in the epidermis of psoriasis vulgaris, a benign hyperproliferative skin disease, and Bowen's disease, a pre-malignant hyperproliferative skin disease, and normal skin. DNA replicating cells were detected by anti-BrdU monoclonal antibody after incubating tissue sections with BrdU, and EGF receptors were detected by the anti-EGF receptor monoclonal antibody B4G7. In normal skin, DNA replicating cells were localized exclusively in the basal and suprabasal layers. EGF receptor expression was observed most strongly in the basal and parabasal layers, but diminished gradually towards the upper squamous layer. In psoriatic skin, DNA replicating cells were also localized in the basal and parabasal layers, but the number of these mitotic cells was about 10 times higher than in normal skin. In this case, more EGF receptors were detected in all viable layers of the epidermis. Apparently normal skin adjacent to psoriasis lesions showed persistent expression of EGF receptors in the upper squamous layer without an increased number of DNA replicating cells in the basal and parabasal layers. In Bowen's disease, DNA replicating cells and EGF receptor expressing cells were distributed in all layers of the epidermis. These findings indicate that the increased production of EGF receptors may be, in part, responsible for the hyperproliferative state of the epidermis and that cells in the upper squamous layer of psoriasis may have lost a mechanism by which EGF receptor expression is diminished thus allowing differentiation. This altered process of EGF receptor production may be involved in the onset of psoriasis vulgaris.

Notizen: Summary Pemphigus is an autoimmune mucocutaneous bullous disease characterized by autoantibodies against the cell surfaces of epidermal keratinocytes. Six cases with deposition of both IgG and IgA on keratinocyte cell surfaces have been reported in the recent literature. We provisionally termed these cases IgG/IgA pemphigus. We describe a 42-year-old Japanese woman with clinical and histopathological features resembling herpetiform pemphigus who demonstrated in vivo bound and circulating anticell surface autoantibodies of both IgG and IgA classes on immunofluorescence examination. Enzyme-linked immunosorbent assay using baculovirus-expressed recombinant desmoglein (Dsg) 1 and Dsg 3 showed that both IgG and IgA antibodies reacted with Dsg1. The reactivity was completely adsorbed with preincubation of serum with Dsg1 baculoprotein, further confirming the exclusive reactivity of both IgG and IgA antibodies with Dsg1. This is the second case of IgG/IgA pemphigus in which the human target antigens for both IgG and IgA antibodies have been unequivocally identified. This study provides further evidence that IgG/IgA pemphigus is a distinct disease entity.

Notizen: Background  We have shown previously that human desmocollin (Dsc) 1 is recognized by IgA autoantibodies of subcorneal pustular dermatosis (SPD) type IgA pemphigus. However, the presence of IgG anti-Dsc autoantibodies is still controversial, and antibodies to Dsc2 and Dsc3 have not been clearly identified.Objectives  To investigate this by producing recombinant proteins consisting of the entire extracellular domains of human Dsc1, 2 and 3 in baculovirus, and to use them to establish an enzyme-linked immunosorbent assay (ELISA).Methods  By this ELISA, we examined in total 165 cases of various types of autoimmune bullous diseases, as well as 23 normal controls.Results  None of 45 sera of classical pemphigus showed either IgG or IgA antibodies to any Dsc. In contrast, one atypical pemphigus serum showed both IgG and IgA antibodies to Dsc1, which were adsorbed by incubation with Dsc1 baculoprotein. Furthermore, this ELISA detected both IgA and IgG anti-Dsc3 antibodies in one atypical case, and IgA antibodies to both Dsc2 and Dsc3 in another. This reactivity was confirmed by positive IgA immunofluorescence with Dsc2 and Dsc3 expressed on COS-7 cells. These results show that both IgG and IgA autoantibodies against all of Dsc1–3 are present in the sera of particular cases of nonclassical pemphigus, except for IgG antibodies to Dsc2, but that they are not detected in classical pemphigus. Unexpectedly, although IgA antibodies of all of eight SPD type IgA pemphigus sera reacted with Dsc1 expressed on COS-7 cells, only one serum was positive in Dsc1 ELISA for IgA.Conclusions  This result indicates either that Dscs expressed by baculovirus may not adopt the correct conformation or that Dscs may need association with other molecules to express all the epitopes for autoantibodies.

Notizen: Summary The clinical phenotype of pemphigus is well explained by the combination of desmoglein (Dsg) 1 and Dsg3 distribution pattern and antiDsg autoantibody profile (Dsg compensation theory). It has been reported that neonatal skin has a similar Dsg distribution pattern to adult mucosal epithelia. We describe a newborn girl with mucocutaneous pemphigus vulgaris (PV) from a mother with mucosal dominant PV. The mother had had painful oral erosions for at least 7 months. Histopathological examination and direct and indirect immunofluorescence studies confirmed the diagnosis of PV and neonatal PV in the mother and daughter, respectively. The mother had a high titre of anti-Dsg3 IgG and a low titre of antiDsg1 IgG, while the neonate had only a high titre of anti-Dsg3 IgG, but no detectable antiDsg1 IgG. AntiDsg3 IgG, which caused the oral dominant phenotype in the mother, induced extensive oral as well as cutaneous lesions in the neonate. Our case provides clinical evidence for the Dsg compensation theory in neonatal PV.

Notizen: Background The two major subtypes of pemphigus include: pemphigus vulgaris (PV) and pemphigus foliaceus. Only limited data are available on the epidemiology of these diseases.Objective The aim of the present study was to estimate the gender- and age-specific incidences of PV in two well-defined regions of Germany and to compare the incidences among native Germans with those in citizens from other countries living in Germany.Methods We performed a retrospective review of records from all patients that were diagnosed with PV at the Departments of Dermatology in Würzburg and Mannheim between 1989 and 1997.Results During the observation period, 14 patients were diagnosed with PV coming from an area with 1.46 million residents. With regard to the patients’ age, the highest incidence for women was found in the 51–65-year-old-age group with 2.34 [95% confidence interval (CI): 0.36; 7.76] new cases per 1 million inhabitants per year. The highest incidence for men was observed in the over 65-year-old age group with 3.72 (95% CI: 0.95; 9.8) cases/million per year. In the 51–65-year-old age group, we found a 25-fold higher incidence of PV in foreigners living in Germany compared with native Germans. The age-adjusted incidence of PV was ninefold higher in foreigners compared with native Germans. Interestingly, all non-German patients came from two southern European countries (Turkey and Italy).Conclusions The age-adjusted incidence of PV differs between native Germans and foreigners living in Germany. Further studies are necessary to address the risk factors (genetic and/or environmental) that contribute to this difference.