[Modern diagnostics of autoimmune bullous diseases]. / Moderne Diagnostik bullöser Autoimmundermatosen.

Blisters and erosions of skin and mucous membranes are key features of the clinically heterogeneous group of autoimmune bullous diseases (AIBDs). These can be divided into pemphigoid diseases with autoantibodies against structural proteins of the dermal-epidermal junction, pemphigus diseases with autoantibodies against desmosomal proteins, and dermatitis herpetiformis with autoantibodies against transglutaminases 1 and 2. A differentiation based only on clinical features is often not sufficient. After researching the literature in PubMed, the current diagnostic tools for AIBDs are summarized.AIBD diagnostics are performed using histology, direct and indirect immunofluorescence, as well as ELISA and immunoblotting. For serological diagnosis, the conventional multistep approach or multivariant assays for the analysis of autoantibodies against several target antigens in parallel can be applied. These allow a precise classification of AIBD and therefore a tailored use of different therapeutic regimens, e.g., for bullous pemphigoid or pemphigus foliaceus/vulgaris, as well as identification of disease entities with a known association with neoplasia.Direct immunofluorescence is still the diagnostic mainstay of AIBDs. However, novel serological assays, such as target-antigen-specific ELISA or indirect immunofluorescence systems using BIOCHIP™ mosaic technology, allow serologic diagnosis in most AIBD patients and the exact classification of the disease entity at the molecular level.

Evaluation and Comparison of Clinical and iLaboratory Characteristics of Patients With IgA Epidermolysis Bullosa Acquisita, Linear IgA Bullous Dermatosis, and IgG Epidermolysis Bullosa Acquisita.

IMPORTANCE: Immunoglobulin A (IgA) epidermolysis bullosa acquisita (EBA) is an autoimmune skin blistering disease with IgA autoantibodies directed against type VII collagen. There is debate whether it should be considered part of the clinical spectrum of linear IgA bullous dermatosis (LABD) or a separate disease entity. OBJECTIVE: This cohort study aimed to define the clinical features and treatment responses of IgA EBA and anti-BP180-driven LABD, and to compare the prevalences of IgA EBA anti-BP180 LABD and classic IgG-mediated EBA in an autoimmune diagnostic laboratory database. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study and case series study included demographic, immunopathologic, and serologic data from 300 patients diagnosed with IgA EBA, IgG EBA, or LABD. Furthermore, clinical features and treatment responses of IgA EBA were analyzed in a case series including 4 patients with IgA EBA. All patients from the database of the autoimmune diagnostic laboratory at the Department of Dermatology, University of Lübeck, Germany, who were diagnosed with IgA EBA, LABD, or IgG EBA between October 2010 and July 2019 were included. Four patients diagnosed with IgA EBA between October 2015 and January 2018 are described in detail. MAIN OUTCOMES AND MEASURES: The clinical course of IgA EBA was observed before and during different treatments. RESULTS: The database search yielded 21 cases of IgA EBA (12 females [57%]/9 males [43%]), 222 cases of LABD (111 females [51%]/106 males [49]), and 57 cases of IgG EBA (29 females [50%]/28 males [48%]). The median (range) age of each cohort was 64 (4-81) years for IgA EBA, 56 (3-92) years for IgG EBA, and significantly older compared with IgG EBA (P = .002) for those with LAPD (median [range], 70 [1-94] years). The patients with IgA EBA exhibited heterogeneous clinical presentations that significantly differed from those of anti-BP180 LABD. All 4 patients with IgA EBA described in detail were first treated with dapsone, but only 1 responded to this treatment. The others required treatment with high-dose dexamethasone, rituximab, and/or intravenous immunoglobulins to achieve partial clinical remission. CONCLUSIONS AND RELEVANCE: Overall, the findings of this cohort study and small case series suggest that IgA EBA may be more common than expected and may require more intensive systemic treatment than LABD, suggesting it should be considered a separate disease entity.

iMATCH: an integrated modular assembly system for therapeutic combination high-capacity adenovirus gene therapy.

Adenovirus-mediated combination gene therapies have shown promising results in vaccination or treating malignant and genetic diseases. Nevertheless, an efficient system for the rapid assembly and incorporation of therapeutic genes into high-capacity adenoviral vectors (HCAdVs) is still missing. In this study, we developed the iMATCH (integrated modular assembly for therapeutic combination HCAdVs) platform, which enables the generation and production of HCAdVs encoding therapeutic combinations in high quantity and purity within 3 weeks. Our modular cloning system facilitates the efficient combination of up to four expression cassettes and the rapid integration into HCAdV genomes with defined sizes. Helper viruses (HVs) and purification protocols were optimized to produce HCAdVs with distinct capsid modifications and unprecedented purity (0.1 ppm HVs). The constitution of HCAdVs, with adapters for targeting and a shield of trimerized single-chain variable fragment (scFv) for reduced liver clearance, mediated cell- and organ-specific targeting of HCAdVs. As proof of concept, we show that a single HCAdV encoding an anti PD-1 antibody, interleukin (IL)-12, and IL-2 produced all proteins, and it led to tumor regression and prolonged survival in tumor models, comparable to a mixture of single payload HCAdVs in vitro and in vivo. Therefore, the iMATCH system provides a versatile platform for the generation of high-capacity gene therapy vectors with a high potential for clinical development.

Large International Validation of ABSIS and PDAI Pemphigus Severity Scores.

The Pemphigus Disease Area Index (PDAI) and Autoimmune Bullous Skin Disorder Intensity-Score (ABSIS) scores have been proposed to provide an objective measure of pemphigus activity. These scores have been evaluated only on already treated patients mainly with mild to moderate activity. The objective was to assess the interrater reliability of ABSIS and PDAI scores and their correlation with other severity markers in a large international study. Consecutive patients with newly diagnosed pemphigus were enrolled in 31 centers. Severity scores were recorded during a 24-month period by the same two blinded investigators. Serum was collected at each visit for ELISA measurement of anti-desmoglein antibodies. The intraclass correlation coefficient (ICC) and Spearman rank correlation coefficient were calculated. A total of 116 patients with pemphigus vulgaris (n = 84) or pemphigus foliaceus (n = 32) were included. At baseline, the ABSIS and PDAI ICCs were 0.90 (95% confidence interval [CI] = 0.85-0.93), and 0.91(95% CI = 0.87-0.94), respectively. The ICCs for PDAI were higher in moderate and extensive pemphigus (ICC = 0.82, 95% CI = 0.63-0.92 and ICC = 0.80, 95% CI = 0.62-0.90, respectively) than in patients with intermediate (significant) extent (ICC = 0.50, 95% CI = 0.27-0.68). Conversely, the ICCs for ABSIS were lower in patients with moderate extent (ICC = 0.44, 95% CI = 0.004-0.74) than in those with intermediate or extensive forms, (ICC = 0.69, 95% CI = 0.51-0.81 and ICC = 0.75, 95% CI = 0.51-0.88, respectively). During patients' follow-up, the ICCs of both ABSIS and PDAI scores remained higher than 0.70. ABSIS and PDAI skin (r = 0.71 and r = 0.75) but not mucosal (r = 0.32 and r = 0.37) subscores were correlated with the evolution of anti-DSG1 and anti-DSG3 ELISA values, respectively. ABSIS and PDAI scores are robust tools to accurately assess pemphigus activity.

Mouse gridlock: no aortic coarctation or deficiency, but fatal cardiac defects in Hey2 -/- mice.

Gridlock (grl) is one of the first mutations characterized from the large zebrafish mutagenesis screens, and it results in an arterial (aortic) maturation defect, which was proposed to resemble aortic coarctation, a clinically important human malformation. While the grl mutation appears to be a hypomorph, grl knockdown experiments have shown even stronger effects on arterial development. We have generated a knockout of the murine Hey2 (gridlock) gene to analyze the mammalian phenotype. Surprisingly, Hey2 loss does not affect aortic development, but it instead leads to a massive postnatal cardiac hypertrophy with high lethality during the first 10 days of life. This cardiomyopathy is ameliorated with time in surviving animals that do not appear to be manifestly impaired during adult life. These differences in phenotypes suggest that changes in expression or function of genes during evolution may lead to quite different pathological phenotypes, if impaired.

Expression of Notch pathway genes in the embryonic mouse metanephros suggests a role in proximal tubule development.

The interaction of neighboring cells via Notch signalling leads to cell fate determination, differentiation and patterning of highly organized tissues. Mice with targeted disruption of genes from the Notch signal transduction pathway display defects in the developing somites, neurogenic structures, blood vessels, heart and other organs. Recent studies have added requirements for Notch signalling during kidney, pancreas and thymus morphogenesis. Here, we describe the expression of all four receptors (Notch1-4), the five transmembrane ligands (Dll1, 3, 4, Jag1 and Jag2), intracellular effectors (the Hey genes) and extracellular modulators (Lfng, Mfng, Rfng) in the developing mouse metanephros. Our results point to a Lfng-dependent role for Notch signalling in the development of nephron segments, especially the proximal tubules.

Overlapping expression pattern of the actin organizers Spir-1 and formin-2 in the developing mouse nervous system and the adult brain.

The Wiskott-Aldrich homology domain 2 (WH2) family protein Spir and the formin Cappuccino belong to two distinct classes of actin organizers. Despite their functional classification as actin organizers, a major defect of Drosophila spire and cappuccino mutant oocytes is a failure in the orientation of microtubule plus ends towards the posterior pole. Mammalian homologues of spire are the spir-1 and spir-2 genes. The mouse and human formin-1 and formin-2 genes have high similarity to the cappuccino gene. The mouse formin-2 gene has been found to be expressed in the developing nervous system and in neuronal cells of the adult brain. By analyzing the expression of the spir-1 gene we show that spir-1 and formin-2 have a nearly identical expression pattern during mouse embryogenesis and in the adult brain. In mouse embryos both genes are expressed in the developing nervous system. In the adult brain high expression of the genes was found in the Purkinje cells of the cerebellum and in neuronal cells of the hippocampus and dentate gyrus.

Individual variability in cyclosporin A sensitivity: the assessment of functional measures on CD28-mediated costimulation of human whole blood T lymphocytes.

The quantitative analysis of cyclosporin A (CsA) effects might be helpful for optimizing immunosuppressive treatment after allogeneic organ transplantation in individual patients, as rejection can occur despite the existence of CsA blood levels within therapeutic ranges. Previous investigations found that costimulation of the CD28 pathway generally mediates CsA-resistant proliferation of T cell receptor (TCR)-activated T lymphocytes. However, here we describe considerable interindividual variation regarding the immunosuppressive effects of CsA (1000 microg/L) on anti-CD3/CD28 T cell costimulation in a human whole blood assay. In the in vitro study, we found a significant reduction of T cell proliferation, activation marker expression (CD25, CD69) on the T cell surface, and interleukin-2 (IL-2) protein expression in whole blood samples of all healthy subjects (n = 11). However, the investigation of cytokine mRNA profiles revealed variable results of in vitro CsA sensitivity. Whole blood samples of 3 of 11 healthy individuals demonstrated a marked suppression of IL-2 mRNA expression (>50%) and a partial inhibition of IL-4, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) mRNA expression on addition of CsA. In contrast, the remaining 8 healthy individuals had cytokine mRNA expression levels that were unaffected or even increased when CsA was administered in vitro. In patients undergoing CsA monotherapy (ex vivo study, n = 9), we found a significant suppression of IL-2 mRNA levels in 4 of 9 patients ex vivo. Thus, we cannot confirm a universal CsA resistance of T cells on anti-CD3/CD28 costimulation. Instead, our results suggest an individual degree of CsA sensitivity that might be more consistent with clinical experience. Prospective studies are necessary to determine if individual degrees of CsA sensitivity correlate with clinical events and are associated with a low or high risk of transplant rejection.

Fjx1: a notch-inducible secreted ligand with specific binding sites in developing mouse embryos and adult brain.

The mouse fjx1 gene was identified as a homologue to the Drosophila gene four-jointed (fj). Fj encodes a transmembrane type II glycoprotein that is partially secreted. The gene was found to be a downstream target of the Notch signaling pathway in leg segmentation and planar cell polarity processes during eye development of Drosophila. Here, we show that fjx1 is not only conserved in vertebrates, but we also identified the murine fjx1 gene as a direct target of Notch signaling. In addition to the previously described expression of fjx1 in mouse brain, we show here that fjx1 is expressed in the peripheral nervous system, epithelial cells of multiple organs, and during limb development. The protein is processed and secreted as a presumptive ligand. Through the use of an fjx1-AP fusion protein, we could visualize fjx1 binding sites at complementary locations, supporting the notion that fjx1 may function as a novel signaling molecule.

Cloning and expression analysis of the mouse stroma marker Snep encoding a novel nidogen domain protein.

The vertebrate kidney develops through a series of mesenchymal-epithelial interactions between the ureteric bud and the metanephrogenic mesenchyme to form nephrons and the collecting system, which are both embedded in the renal interstitium. The interstitial stromal cells are an essential prerequisite for regular kidney development, but their origin and function is poorly understood. They are found in the kidney periphery and the medulla and are likely derived from the kidney mesenchyme and/or from migrating neural crest cells. During late kidney development, stromal cells are lost through massive apoptosis. We have identified a novel marker of kidney stroma cells, Snep (stromal nidogen extracellular matrix protein), that is additionally expressed in mesenchymal cells of other embryonic tissues and within the nervous system. Of interest, Snep transcripts are also found at sites of embryonic apoptosis. Furthermore, comparative expression analysis of kidney stroma markers suggests that Snep is expressed in a specific subpopulation of stromal cells and may provide environmental cues to support regular development.

The Notch target genes Hey1 and Hey2 are required for embryonic vascular development.

The Delta-Notch signaling pathway plays a central role in the development of most vertebrate organs. The Hey family of bHLH transcription factors are direct targets of Notch signaling. Loss of Hey2 in the mouse leads to cardiac defects with high postnatal lethality. We have now generated a mouse Hey1 knockout that has no apparent phenotypic defect. The combined loss of Hey1 and Hey2, however, results in embryonic death after embryonic day 9.5 (E9.5) with a global lack of vascular remodeling and massive hemorrhage. Initial vasculogenesis appears unaffected, but all subsequently developing major vessels in the embryo and yolk sac are either small or absent. Furthermore, the placental labyrinth completely lacks embryonic blood vessels. Similar vascular defects are observed in Jagged1 and Notch1 knockout mice. In the latter we found Hey1 and Hey2 expression in yolk sacs to be strongly reduced. Remaining large arteries in both Notch1 and Hey1/Hey2 knockout mice fail to express the arterial endothelial markers CD44, neuropilin1, and ephrin-B2. This indicates that Hey1/Hey2 are essential transducers of Notch signals in cardiovascular development that may mediate arterial cell fate decision.

Delayed cytokine mRNA expression kinetics after T-lymphocyte costimulation: a quantitative measure of the efficacy of cyclosporin A-based immunosuppression.

BACKGROUND: Because cyclosporin A (CsA) and glucocorticoids inhibit the production of interleukin-2 (IL-2) and other cytokines, quantitative analysis of cytokine mRNA might constitute a pharmacodynamic measure for immunosuppressive drug effects. We investigated whether immunosuppressive drugs influence cytokine mRNA expression kinetics during T-cell costimulation. METHODS: We used a human whole blood assay to determine basal (unstimulated) IL-2, IL-4, and tumor necrosis factor-alpha (TNF-alpha) mRNA concentrations and expression kinetics after anti-CD3/anti-CD28 monoclonal antibody costimulation in kidney transplant recipients undergoing CsA-based immunosuppressive triple therapy and in healthy controls (ex vivo study I). The effect of CsA on IL-2 mRNA expression kinetics was also determined ex vivo in patients undergoing CsA monotherapy (ex vivo study II) and after in vitro addition of CsA. RESULTS: In ex vivo study I, basal TNF-alpha mRNA but not IL-2 and IL-4 mRNA was decreased in kidney transplant patients. We observed shifts in peak IL-2 and IL-4 (from 8 to 24 h) and TNF-alpha (from 4 to 8 h of costimulation) mRNA expression in kidney transplant patients after T-cell costimulation. In patients undergoing CsA monotherapy (ex vivo study II), the inhibitory effect of CsA was detectable as an individually delayed increase in IL-2 mRNA during costimulation. In vitro addition of CsA also induced a dose-independent displacement of IL-2 mRNA expression kinetics (i.e., a delay). CONCLUSIONS: A delayed increase in cytokine mRNA expression during T-cell costimulation may represent a sensitive effect of immunosuppression. The single analysis of one absolute or peak mRNA value could be misleading. For prospective studies involving measurement of cytokine mRNA, we therefore suggest the parameter "area of cytokine mRNA expression over time", which should include absolute cytokine mRNA values at two different time points of mRNA kinetics.

Developmental expression and biochemical characterization of Emu family members.

Kidney development has often served as a model for epithelial-mesenchymal cell interaction where the branching epithelium of the ureteric bud induces the metanephrogenic mesenchyme to form epithelial nephrons. In a screen for genes differentially expressed during kidney development, we have identified a novel gene that is dynamically expressed in the branching ureter and the developing nephrons. It was designated Emu1 since it shares an N-terminal cysteine-rich domain with Emilin1/2 and Multimerin. This highly conserved EMI domain is also found in another novel protein (Emu2) of similar protein structure: an N-terminal signal peptide followed by the EMI domain, an interrupted collagen stretch, and a conserved C-terminal domain of unknown function. We identified two further secreted EMI domain proteins, prompting us to compare their gene and protein structures, the EMI domain phylogeny, as well as the embryonic expression pattern of known (Emilin1/2, Multimerin) and novel (Emu1/2, Emilin3, Multimerin2) Emu gene family members. Emu1 and Emu2 not only show a similar structural organization, but furthermore a striking complementary expression in organs developing through epithelial-mesenchymal interactions. In these tissues, Emu1 is restricted to epithelial and Emu2 to mesenchymal cells. Preliminary biochemical analysis of Emu1/2 confirmed that they are secreted glycoproteins which are attached to the extracellular matrix and capable of forming homo- and heteromers via disulfide bonding. The widespread, but individually distinct expression patterns of all Emu gene family members suggest multiple functions during mouse embryogenesis. Their multidomain protein structure may indicate that Emu proteins interact with several different extracellular matrix components and serve to connect and integrate the function of multiple partner molecules.

Sensitivity of whole-blood T lymphocytes in individual patients to tacrolimus (FK 506): impact of interleukin-2 mRNA expression as surrogate measure of immunosuppressive effect.

BACKGROUND: To optimize immunosuppressive treatment in individual transplant patients, functional measurements of the effects of tacrolimus (FK 506) are of clinical importance. Previous investigations have demonstrated the occurrence of tacrolimus-resistant production of interleukin-2 (IL-2) in vitro, which may explain in part why rejection episodes are still a frequent problem despite attainment of therapeutic blood concentrations and HLA matching. However, an adequate surrogate marker to define the tacrolimus response in individual patients has not been established. METHODS: We investigated the immunosuppressive effects of tacrolimus on anti-CD3/anti-CD28 T-cell costimulation in a human whole-blood assay, analyzing T-cell proliferation, activation marker expression (CD25, CD69), IL-2 protein expression, and cytokine mRNA expression in vitro (n = 11 healthy individuals). We also quantified IL-2 mRNA expression in patients undergoing tacrolimus (n = 4) or cyclosporin A (CsA; n = 4) monotherapy before ex vivo living-donor kidney transplantation. RESULTS: T-cell proliferation; CD25, CD69, and IL-2 concentrations; and IL-4 mRNA were significantly decreased in vitro. In contrast, cytokine mRNA profiles revealed variable tacrolimus sensitivity. Whole-blood samples from 3 of 11 healthy individuals demonstrated marked suppression of IL-2 mRNA expression (>50%) when tacrolimus was administered in vitro. When CsA was added to whole-blood cultures, the influence on IL-2 mRNA expression was comparable to that of tacrolimus in 9 of 11 individuals. Two individuals responded conversely, indicating that differences in the in vitro response to tacrolimus and CsA among individuals may be attributable to potential heterogeneity in the involvement of the CD28 pathway. Kinetic profiles of IL-2 mRNA expression also revealed individually distinct degrees of calcineurin inhibitor sensitivity in patients undergoing tacrolimus or CsA monotherapy before living-donor kidney transplantation. CONCLUSIONS: Our results suggest an individual degree of calcineurin inhibitor sensitivity of activated whole-blood lymphocytes based on IL-2 mRNA expression. Our approach is potentially valuable for identifying transplant patients in whom IL-2 mRNA expression is unaffected or even enhanced after initiation of immunosuppressive therapy. Such individuals may be less sensitive to the immunosuppressive agent and therefore at increased risk of transplant rejection. Prospective studies are necessary to determine the correlation of IL-2 mRNA expression with the clinical risk of transplant rejection.

Phenotypic variability in Hey2 -/- mice and absence of HEY2 mutations in patients with congenital heart defects or Alagille syndrome.

The genetic alterations leading to congenital heart defects (CHD) are still poorly understood. We and others have recently shown that in mice loss of Hey2 results in a high incidence of fatal ventricular and atrial septal defects, combined with tricuspid stenosis or atresia in some cases. The phenotype has been postulated to resemble human tetralogy of Fallot. Our analysis of CD1 outbred mice suggests that phenotypic consequences of Hey2 loss can be quite variable and dependent on modifier genes as we detected only isolated VSDs with lower prevalence and a significantly reduced mortality rate in this strain. Since Hey2 is one of the few Notch target genes, it is also conceivable that HEY2 mutations may account for cases of Alagille syndrome (AGS: variable combinations of heart, skeleton, eye, and facial malformations and cholestasis), in which the typical mutations of the Notch ligand JAG1 cannot be found. To clarify the role of HEY2 in human CHD and AGS, we screened by direct sequencing 23 children with CHD and 38 patients diagnosed with AGS, which lack mutations in the JAG1 gene. We found two types of silent changes in the coding region: a CTT-->CTG transition in exon 3 and a CTG-->CTC polymorphism in exon 5. Furthermore, a heterozygous SNP in the splice donor site of exon 4 was detected that is unlikely to disrupt splicing. Although the high incidence and variability of human congenital heart defects implies a multifactorial genetic basis, our results suggest that mutation of HEY2 is not a major contributing factor.