Efficacy and safety of adjuvant immunoadsorption in pemphigus vulgaris and pemphigus foliaceus (IA-Pem Study): a multicentre randomized controlled trial.

BACKGROUND: Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are potentially life-threatening autoimmune blistering diseases. Treatment is based on long-term immunosuppression with high doses of glucocorticosteroids in combination with potentially corticosteroid-sparing agents and/or rituximab. Immunoadsorption (IA) has emerged as a fast-acting adjuvant treatment option. OBJECTIVES: To assess the clinical efficacy of IA in addition to best medical treatment (BMT). METHODS: We conducted a multicentre (26 centres from Germany and Austria) randomized controlled trial in 72 patients with newly diagnosed, relapsed or chronic active PV or PF (34 female patients and 38 male patients, aged 42-72 years) comparing BMT (prednisolone 1.0 mg kg-1 per day plus azathioprine or mycophenolate) with adjuvant IA (BMT + IA). Central 1 : 1 randomization was done at the coordinating centre for clinical trials (KKS Marburg). The primary endpoint was analysed using Kaplan-Meier and Cox regression methods. RESULTS: The study was ended prematurely owing to safety concerns after random allocation of 72 patients to BMT + IA (n = 34) or BMT (n = 38). The primary endpoint, time to complete remission on therapy, was not significantly different for the two groups [hazard ratio (HR) 1.35, 95% confidence interval (CI) 0.68-2.69; P = 0.39]. The cumulative dose of prednisolone was significantly lower in the BMT + IA group compared with BMT alone (difference -1214, 95% CI -2225 to -70; P = 0.03). In a post hoc analysis, patients with more extensive PV/PF showed a tendency towards a shorter time to remission in the BMT + IA group compared with the BMT group (HR 1.87, P = 0.17 in patients with baseline Pemphigus Disease Area Index ≥ 15). While more adverse events were observed in patients in the BMT group (29 vs. 25), severe adverse events were more frequent in patients in the BMT + IA group (17 events in 10 patients vs. 11 events in 8 patients). CONCLUSIONS: In this study, adjuvant IA did not demonstrate a shorter time to clinical remission, but a corticosteroid-sparing effect was observed. In patients with extensive PV/PF, post hoc analysis suggests that adjuvant IA may lead to earlier remission, but potential adverse events must be carefully weighed against the expected benefits.

Pemphigus vulgaris and pemphigus foliaceus are potentially life-threatening autoantibody-driven blistering diseases, which present with erosions or blisters on skin and/or mucous membranes. Treatment is based on long-term immunosuppressive agents. Immunoadsorption (IA) is a procedure that removes autoantibodies from the blood and has emerged as a fast-acting treatment option for pemphigus.We conducted a trial comparing best medical treatment (BMT) (prednisolone 1.0 mg kg per day plus azathioprine or mycophenolate) with best medical treatment plus IA (BMT + IA). A total of 26 centres from Germany and Austria recruited 72 patients with active pemphigus (34 women and 38 men, aged 42­72 years) who were randomly allocated in a ratio of 1 : 1 to the treatment groups.Following inclusion of 72 patients in the BMT + IA (n = 34) or BMT (n = 38) groups, the study ended prematurely owing to safety concerns. The main outcome, time to complete remission (relief of all symptoms) while still receiving therapy, was not significantly different for the two groups. In contrast, the cumulative dose of prednisolone was significantly lower in the BMT + IA compared with BMT alone. In an additional analysis, patients with more extensive pemphigus showed a tendency towards a shorter time to remission in the BMT + IA group compared with the BMT group. While more adverse events were observed in the BMT group (29 vs. 25), severe adverse events were more frequent in the BMT + IA group (17 vs. 11). In this study, IA did not show a shorter time to clinical remission, but a prednisolone-sparing effect was observed. In patients with extensive pemphigus, adjuvant IA may possibly lead to earlier remission, but potential adverse events must be carefully weighed against the expected benefits.

Laminin ß4 is a constituent of the cutaneous basement membrane zone and additional autoantigen of anti-p200 pemphigoid.

BACKGROUND: Anti-p200 pemphigoid is a subepidermal autoimmune blistering disease (AIBD) characterized by autoantibodies against a 200 kDa protein. Laminin γ1 has been described as target antigen in 70% to 90% of patients. No diagnostic assay is widely available for anti-p200 pemphigoid, which might be due to the unclear pathogenic relevance of anti-laminin γ1 autoantibodies. OBJECTIVE: To identify a target antigen with higher clinical and diagnostic relevance. METHODS: Immunoprecipitation, mass spectrometry, and immunoblotting were employed for analysis of skin extracts and sera of patients with anti-p200 pemphigoid (n = 60), other AIBD (n = 33), and healthy blood donors (n = 29). To localize the new antigen in skin, cultured keratinocytes and fibroblasts, quantitative real-time polymerase chain reaction and immunofluorescence microscopy were performed. RESULTS: Laminin ß4 was identified as target antigen of anti-p200 pemphigoid in all analyzed patients. It was located at the level of the basement membrane zone of the skin with predominant expression in keratinocytes. LIMITATIONS: A higher number of sera needs to be tested to verify that laminin ß4 is the diagnostically relevant antigen of anti-p200 pemphigoid. CONCLUSION: The identification of laminin ß4 as an additional target antigen in anti-p200 pemphigoid will allow its differentiation from other AIBD and as such, improve the management of these rare disorders.

Lymphocyte-predominant lesional inflammatory infiltrates of the skin are associated with mucosal-dominant phenotype in pemphigus.

INTRODUCTION: Pemphigus is a potentially life-threatening autoimmune blistering disease. To date, studies assessing the association of histopathology with clinical phenotype are lacking. We sought to evaluate the main histopathologic findings and, also, the potential links between cutaneous inflammatory infiltrates and clinical characteristics in pemphigus. METHODS: We conducted a retrospective cohort study in patients diagnosed with pemphigus vulgaris (PV) and pemphigus foliaceus (PF) in a referral center for autoimmune blistering diseases. RESULTS: A total of 124 patients were included in the study (97 had PV and 27 had PF). On biopsy specimens, PV was more frequently associated with the "row of tombstones" feature (36.1% vs. 11.1%, p = 0.013), and PF was associated with acanthosis (44.4% vs. 23.7%, p = 0.034). Acantholysis was found in the upper half of the epidermis in PF (96.3% vs. 5.15%, p < 0.001), as opposed to the lower half in PV (75.2% vs. 0%, p = 0.002). Patients with lymphocyte-predominant inflammatory infiltrates in lesional skin specimens presented with a higher frequency of the mucosal-dominant phenotype (25.5% vs. 9.1%, p = 0.014), higher-density cellular infiltrate (100% vs. 41.6%, p < 0.001), and more frequent acantholytic cells (42.6% vs. 23.4%, p = 0.025). Neutrophil-predominant infiltrates in specimens from lesional skin were linked to a milder disease based on median Pemphigus Disease Area Index (38.9% vs. 13.2%, p = 0.036) and Autoimmune Bullous Skin Disorder Intensity Score (20.2 vs. 36.3, p = 0.019), while eosinophil-predominant inflammatory infiltrates were more often associated with eosinophilic spongiosis (100% vs. 23.1%, p = 0.014). CONCLUSIONS: Lymphocyte-predominant infiltrates in lesional skin specimens of pemphigus patients predict a mucosal-dominant phenotype, while neutrophil-predominant infiltrates are associated with a milder disease.

Evaluation of the Diagnostic Value of Oesophageal Biopsies for Direct Immunofluorescence Microscopy in Mucous Membrane Pemphigoid.

Mucous membrane pemphigoid is an autoimmune blistering disorder characterized by predominant involvement of surface-close epithelia and linear depositions of immunoreactants at the dermal-epithelial junction on direct immunofluorescence microscopy. A major diagnostic difficulty is the frequent need for multiple biopsies to facilitate the diagnosis. Although oesophageal involvement is a rare, but life-threatening manifestation, the relevance of oesophageal direct immunofluorescence sampling is unclear. This retrospective monocentric study evaluated 67 non-lesional biopsies from 11 patients with mucous membrane pemphigoid and clinical symptoms suggestive of oesophageal involvement, comprising 31 samples from the oesophagus and 36 samples from other anatomical sites. Five patients (45.5%) exhibited endoscopic findings compatible with oesophageal involvement of mucous membrane pemphigoid. No correlation was identified between the presence of oesophageal lesions and direct immunofluorescence positivity in lesions from the oesophagus (p = 1.0). Oral and cutaneous samples were significantly more frequently positive by direct immunofluorescence than were oesophageal biopsies (p < 0.0001 and p = 0.0195, respectively). Oesophageal samples yielded significantly less IgG reactivity than oral and cutaneous lesions (p < 0.0001 and p = 0.0126, respectively), and less IgA antibody response than oral lesions (p = 0.0036). In conclusion, oesophageal direct immunofluorescence samples were inferior to oral and cutaneous biopsies for the diagnosis of mucous membrane pemphigoid even when oesophageal lesions compatible with mucous membrane pemphigoid were present at the time of biopsy.

Serum reactivity in dermatitis herpetiformis: an international multicentre study.

BACKGROUND: Dermatitis herpetiformis (DH) is a rare gluten-induced skin disorder characterized predominantly by IgA autoantibodies against endomysium, tissue transglutaminase (TG2/tTG), epidermal transglutaminase (TG3/eTG) and deamidated gliadin. To date, circulating autoantibody reactivity has not been systematically described. OBJECTIVES: Characterization of serum reactivities in DH. METHODS: This multicentre international study analysed sera from 242 patients with DH taken at the time of initial diagnosis. DH-specific IgA and IgG serum autoantibodies were analysed by indirect immunofluorescence (IF) on monkey oesophagus, and by enzyme-linked immunosorbent assay (ELISA) based on recombinant TG2/tTG, TG3/eTG and deamidated gliadin (GAF3X). RESULTS: IgA indirect IF microscopy on monkey oesophagus revealed the highest reactivity (84.3%; specificity 100%) followed by IgA TG2/tTG ELISA (78.5%, specificity 99.0%), IgA TG3/eTG ELISA (72.7%, specificity 95.0%) and IgA GAF3X ELISA (69.0%, specificity 98.5%). CONCLUSIONS: Serum IgA and IgG autoantibodies against endomysium, TG2/tTG, TG3/eTG and deamidated gliadin are highly prevalent in DH. Indirect IF microscopy on monkey oesophagus (IgA) provides the highest diagnostic accuracy that can be further enhanced by 4.5% when combined with IgA TG2/tTG ELISA.

The G protein-coupled receptor 15 (GPR15) regulates cutaneous immunology by maintaining dendritic epidermal T cells and regulating the skin microbiome.

The G protein-coupled receptor 15 (GPR15) regulates homing of different T-cell populations into the gut, thus, preserving tissue homeostasis. Its potential role in the preservation of homeostasis on other body interfaces, including the skin, is less well understood. We addressed the impact of GPR15 on cutaneous T-cell populations and the skin microbiome under steady-state conditions. Genetic deficiency in GPR15 substantially altered the composition of skin-resident T-cell populations. Precisely, dendritic epidermal T cells were almost absent in the epidermis of Gpr15-/- mice. The niche of dendritic epidermal T cells in the epidermis was, instead, populated by αß TCR+ T cells. These changes were associated with shifts in the skin microbiota in Gpr15-/- mice. Collectively, our results uncover a role of GPR15 in the regulation of the cutaneous immune system and, thus, highlight the receptor as important general regulator of tissue homeostasis of exterior body interfaces.

Histopathological risk factors for malignancy in dermatomyositis.

AIMS: To identify possible histopathological risk factors for malignancy in skin biopsies of dermatomyositis patients. METHODS AND RESULTS: We analysed clinical metadata and studied 30 skin biopsies of 11 patients with and 12 patients without associated malignancy, who were treated in one secondary and one tertiary German medical centre between 2009 and 2022 and fulfilling the EULAR/ACR classification criteria for dermatomyositis. Specimens were categorized by malignancy status and evaluated based on haematoxylin and eosin (H&E), periodic acid Schiff (PAS), Alcian Blue, and anti-CD123 immunohistochemistry stains. After correcting for multiple testing, biopsies of patients with cancer exhibited more severe basement membrane thickening (P < 0.05) and pigment incontinence (P < 0.05) compared to patients without tumour burden. Patients with numerous subepidermal melanophages had a more than 5-times increased odds ratio to suffer from an internal malignancy (odds ratio [OR] 5.3, 95% confidence interval [CI] 1.3-54.2, P < 0.05). Furthermore, specimens of the malignancy group presented a distinct superficial distribution pattern of CD123+ plasmacytoid dendritic cells (PDCs, P < 0.01). Extravascular eosinophils were absent in all cases. CONCLUSION: Severity of basement membrane thickening, extent of pigment incontinence, and superficial distribution pattern of CD123+ PDCs could serve as useful histopathological indicators of risk for malignancy in dermatomyositis.

Evidence for a role of extracellular heat shock protein 70 in epidermolysis bullosa acquisita.

Heat shock protein 90 (Hsp90) and Hsp70 are chaperones implicated in different inflammatory disorders, given their property to impact innate and adaptive immune responses. Here, we determined the so far unknown role of extracellular Hsp70 in epidermolysis bullosa acquisita (EBA), an anti-type VII collagen autoantibody-mediated blistering dermatosis. The in vivo pathophysiological relevance of extracellular Hsp70 was demonstrated in an anti-type VII collagen antibody transfer-induced EBA mouse model in which elevated blood levels of this chaperone were recorded. We found that Hsp70-treated mice had a more intense clinical disease severity compared to controls that were paralleled by increased levels of cutaneous matrix metalloproteinase 9 and plasma hydrogen peroxide. The latter finding was confirmed in an independent reactive oxygen species release assay using EBA-specific immune complexes combined with recombinant Hsp70. Finally, cell culture experiments using human naive peripheral blood mononuclear cells (PBMC) revealed that extracellular Hsp70 stimulated the secretion of the T cell-derived pro-inflammatory cytokines IL-6 and IL-8. This work extends knowledge about the role of Hsps in autoimmune bullous diseases, suggesting that extracellular Hsp70 represents a pathophysiological factor and potential treatment target in EBA.

Disease Recurrence during Adjuvant Immune Checkpoint Inhibitor Treatment in Metastatic Melanoma: Clinical, Laboratory, and Radiological Characteristics in Patients from a Single Tertiary Referral Center.

Despite the dramatic improvements in recurrence-free survival in patients with metastatic melanoma treated with immune checkpoint inhibitors (ICI), a number of patients develop metastases during adjuvant therapy. It is not currently possible to predict which patients are most likely to develop disease recurrence due to a lack of reliable biomarkers. Thus, we retrospectively analyzed the case records of all patients who commenced adjuvant ICI therapy between January 2018 and December 2021 in a single university skin cancer center (n = 46) (i) to determine the rates of disease recurrence, (ii) to examine the utility of established markers, and (iii) to examine whether re-challenge with immunotherapy resulted in clinical response. Twelve out of forty-six (26%) patients developed a relapse on adjuvant immunotherapy in our cohort, and the median time to relapse was 139 days. Adjuvant immunotherapy was continued in three patients. Of the twelve patients who developed recurrence during adjuvant immunotherapy, seven had further disease recurrence within the observation period, with a median time of 112 days after the first progress. There was no significant difference comparing early recurrence (<180 days after initiation) on adjuvant immunotherapy to late recurrence (>180 days after initiation) on adjuvant immunotherapy. Classical tumor markers, including serum lactate dehydrogenase (LDH) and S-100, were unreliable for the detection of disease recurrence. Baseline lymphocyte and eosinophil counts and those during immunotherapy were not associated with disease recurrence. Interestingly, patients with NRAS mutations were disproportionately represented (60%) in the patients who developed disease recurrence, suggesting that these patients should be closely monitored during adjuvant therapy.

DNA chip-based diagnosis of onychomycosis and tinea pedis.

BACKGROUND AND OBJECTIVES: Onychomycosis (OM) and tinea pedis (TP) are common fungal infections. Currently, diagnosis is based on direct microscopy and culture that have a low to moderate sensitivity and/or require up to 3-4 weeks until results are obtained. PCR techniques have emerged for the diagnosis of fungal infections, but little is known about their sensitivity and specificity in diagnosing. Here, we compared the diagnostic value of a DNA-chip technology, that detects 56 fungal pathogens, in a single-center prospective diagnostic study with microscopy and culture in suspected OM/TP. PATIENTS AND METHODS: Microscopy, culture and DNA microarray assays were performed on scraping material from patients with suspected OM (n = 67) or TP (n = 73). To test whether swabs can be used as an alternative for scraping, PCR yields were compared in a further 13 patients with OM and 11 patients with TP. RESULTS: DNA microarrays had the highest sensitivity. Combination of DNA-chip technology with microscopy further increased the sensitivity, and results from this combined laboratory diagnosis can be obtained within 24 hours. Comparison of sampling techniques (scraping, dry or wet swab) for DNA-chip assays showed similar results in suspected OM or TP. CONCLUSIONS: DNA-chip technology shows high sensitivity for OM and TP diagnosis, especially when combined with microscopy.

DNA-Chip-basierte Diagnose der Onychomykose und Tinea pedis.

HINTERGRUND UND ZIELE: Onychomykose (OM) und Tinea pedis (TP) sind häufige Pilzinfektionen der Haut. Aktuell basiert die Diagnose vornehmlich auf mikroskopischem Direktnachweis und/oder Kultur. Beide Methoden haben jedoch eine geringe bis mäßige Sensitivität und benötigen teilweise mehrere Wochen, bis endgültige Laborergebnisse vorliegen. Um die Diagnose kutaner Pilzinfektionen zu verbessern, wurden PCR-basierte Methoden entwickelt. Hier haben wir hier die Sensitivität und Spezifität einer Chip-basierten Multiplex-PCR mit mikroskopischen Direktnachweis und verglichen. PATIENTEN UND METHODIK: In einer monozentrischen, prospektiven Studie wurden bei Patienten mit Verdacht auf OM (n  =  67) oder TP (n  =  73) Schuppenpräparate entnommen und mittels mikroskopischem Direktnachweis, Kultur und DNA-Chip-Technologie der Erregernachweis durchgeführt. In einem weiteren Ansatz wurde überprüft, ob Abstriche als Alternative zur Entnahme eines Schuppenpräparates verwendet werden können. Hierfür wurden 24 weitere OM/TP-Patienten rekrutiert und die Ergebnisse der DNA-Chip-Technologie aus Abstrichen mit denen aus den Schuppenpräparaten verglichen. ERGEBNISSE: Im Vergleich aller Methoden hatte die DNA-Chip-Technologie die höchste Sensitivität, eine Kombination von DNA-Chip-Technologie mit mikroskopischem Direktnachweis erhöhte dies weiter. Ergebnisse dieser kombinierten Labordiagnostik sind innerhalb von 24 Stunden verfügbar. Der Vergleich der Probenentnahmetechniken (Abstrich beziehungsweise Schuppenpräparat) zeigte vergleichbare Ergebnisse. SCHLUSSFOLGERUNGEN: Die molekulare Diagnostik (mittels DNA-Chip-Technologie) hat eine hohe Sensitivität für die OM- und TP-Diagnostik, insbesondere in Kombination mit dem mikroskopischen Direktnachweis.

S2k Guideline for the diagnosis and treatment of mucous membrane pemphigoid.

Mucous membrane pemphigoid (MMP) is a pemphigoid disease with predominant mucous membrane involvement. It mainly affects the mucous membranes of the mouth, eyes, nose and pharynx, but also the larynx, trachea, esophagus, genital and perianal regions. The manifestation of the disease covers a wide spectrum from gingival erythema and single oral lesions to severe tracheal strictures that obstruct breathing and conjunctival scarring with marked visual impairment and, not infrequently, blindness. In addition to a clinical picture of predominant mucosal involvement, diagnosis is based on direct immunofluorescence of a peri-lesional biopsy and serology. The main target antigen is BP180 (collagen XVII), and reactivity with laminin 332 is associated with malignancy in approximately 25 % of MMP patients. The treatment of MMP is challenging. On the one hand, due to the involvement of different mucous membranes, good interdisciplinary cooperation is required; on the other hand, due to the rarity of the disease, no randomized controlled clinical trials are available. The aim of this guideline is to present the clinical picture, including severity and scoring systems, and to give guidance for diagnosing and treating this complex disease. In MMP, interdisciplinary cooperation plays an essential role as well as the prompt diagnosis and initiation of adequate therapy in order to avoid irreversible damage to the mucous membranes with serious complications.

Genetic association and differential expression of HLAComplexGroup lncRNAs in pemphigus.

BACKGROUND: Pemphigus is a group of bullous diseases characterized by acantholysis and skin blisters. As for other autoimmune diseases, the strongest genetic associations found so far for pemphigus foliaceus (PF) and vulgaris (PV) are with alleles of HLA genes. However, apart from protein-coding genes, the MHC region includes a set of poorly explored long non-coding RNA (lncRNA) genes, the HLA complex group (HCG). OBJECTIVES: To investigate if HCG lncRNA alleles are associated with pemphigus susceptibility. METHODS AND RESULTS: We analyzed SNPs in 13 HCG lncRNA genes, both in PV (Germany: 241 patients; 1,188 controls) and endemic PF (Brazil: 227 patients; 194 controls), applying multivariate logistic regression. We found 55 associations with PV (pcorr < 0.01) and nine with endemic PF (pcorr < 0.05), the majority located in TSBP1-AS1 (which includes HCG23) and HCG27 lncRNA genes, independently of HLA alleles previously associated with pemphigus. The association of TSBP1-AS1 rs3129949*A allele was further replicated in sporadic PF (p = 0.027, OR = 0.054; 75 patients and 150 controls, all from Germany). Next, we evaluated the expression levels of TSBP1-AS1, TSBP1, HCG23, and HCG27 in blood mononuclear cells of Brazilian patients and controls. HCG27 was upregulated in endemic PF (p = 0.035, log2 FC = 1.3), while TSBP1-AS1 was downregulated in PV (p = 0.029, log2 FC = -1.29). The same expression patterns were also seen in cultured keratinocytes stimulated with IgG antibodies from patients and controls from Germany. TSBP1 mRNA levels were also decreased in endemic PF blood cells (p = 0.042, log2 FC = -2.14). TSBP1-AS1 and HCG27 were also observed downregulated in CD19+ cells of endemic PF (p < 0.01, log2 FC = -0.226 and -0.46 respectively). CONCLUSIONS: HCG lncRNAs are associated with susceptibility to pemphigus, being TSBP1-AS1 and HCG27 also differentially expressed in distinct cell populations. These results suggest a role for HCG lncRNAs in pemphigus autoimmunity.

Genetic variability of immune-related lncRNAs: polymorphisms in LINC-PINT and LY86-AS1 are associated with pemphigus foliaceus susceptibility.

Pemphigus foliaceus (PF) is an autoimmune blistering disease of the skin, clinically characterized by erosions and, histopathologically, by acantholysis. PF is endemic in the Brazilian Central-Western region. Numerous single nucleotide polymorphisms (SNPs) have been shown to affect the susceptibility for PF, including SNPs at long non-coding RNA (lncRNA) genes, which are known to participate in many physiological and pathogenic processes, such as autoimmunity. Here, we investigated whether the genetic variation of immune-related lncRNA genes affects the risk for endemic and sporadic forms of PF. We analysed 692 novel SNPs for PF from 135 immune-related lncRNA genes in 227 endemic PF patients and 194 controls. The SNPs were genotyped by Illumina microarray and analysed by applying logistic regression at additive model, with correction for sex and population structure. Six associated SNPs were also evaluated in an independent German cohort of 76 sporadic PF patients and 150 controls. Further, we measured the expression levels of two associated lncRNA genes (LINC-PINT and LY86-AS1) by quantitative PCR, stratified by genotypes, in peripheral blood mononuclear cells of healthy subjects. We found 27 SNPs in 11 lncRNA genes associated with endemic PF (p < .05 without overlapping with protein-coding genes). Among them, the LINC-PINT SNP rs10228040*A (OR = 1.47, p = .012) was also associated with increased susceptibility for sporadic PF (OR = 2.28, p = .002). Moreover, the A+ carriers of LY86-AS1*rs12192707 mark lowest LY86-AS1 RNA levels, which might be associated with a decreasing autoimmune response. Our results suggest a critical role of lncRNA variants in immunopathogenesis of both PF endemic and sporadic forms.

Immunoglobulin M pemphigoid.

BACKGROUND: Pemphigoid diseases are a heterogeneous group of autoimmune blistering disorders characterized by predominant deposition of immunoglobulin G or immunoglobulin A autoantibodies against structural proteins of the dermoepidermal junction (DEJ). Sole linear immunoglobulin M (IgM) deposits at the DEJ in pemphigoid diseases have been observed; however, IgM-specific target antigens have not been identified. OBJECTIVE: Characterization of patients with IgM pemphigoid. METHODS: Skin biopsy specimens and sera from IgM-positive patients were assessed using histopathology, direct and indirect immunofluorescence microscopy, enzyme-linked immunosorbent assays, immunoblotting, cryosection assay, complement fixation test, and internalization assays. RESULTS: Tissue-bound linear IgM deposits along the DEJ and circulating IgM autoantibodies against type XVII collagen (Col17) were detected. These circulating IgM autoantibodies showed no complement activating or blister inducing capacity, but the ability of Col17 internalization ex vivo. LIMITATIONS: Limited number of patients. CONCLUSION: This study provides further evidence for the role of IgM autoantibodies in pemphigoid disease and highlights Col17 as a target antigen in IgM pemphigoid.

Diagnostic Value and Practicability of Serration Pattern Analysis by Direct Immunofluorescence Microscopy in Pemphigoid Diseases.

In pemphigoid diseases, direct immunofluorescence can be used to differentiate 2 patterns of antibody deposition at the dermal-epidermal junction; u- and n-serrated pattern. The u-serrated pattern is found in epidermolysis bullosa acquisita, and n-serrated pattern in all other pemphigoid diseases. To determine the detection frequency of these serrated patterns and the optimal thickness of biopsy cryosections, 2 patient cohorts obtained form our routine autoimmune laboratory were analysed; a retrospective cohort (n = 226) and a prospective cohort (n = 156). [AQ1] In 76% (291/382) of biopsies, a pattern was recog-nized, of which 96% (278/291) and 4% (13/291) had an n- or u-serrated pattern, respectively. A u-serrated pattern was seen in all epidermolysis bullosa acquisita biopsies confirmed by serology. No antibodies against type VII collagen were detected in any of the sera from biopsies with n-serrated pattern. No differences between the detection frequencies of serrated pattern were seen with respect to age, sex, biopsy site, or section thickness, while the detection frequency was higher in patients with serum anti-BP180 reactivity compared with those without. In conclusion, serrated pattern analysis using direct immunofluorescence has a high detection frequency and specificity for epidermolysis bullosa acquisita and will further facilitate the diagnosis of latter disorder.

Immunomodulator Galectin-9 is Increased in Blood and Skin of Patients with Bullous Pemphigoid.

Massive recruitment of eosinophils into the dermis is a hallmark of bullous pemphigoid pathogenesis. Identifying the chemoattractant(s) guiding eosinophils into the skin in bullous pemphigoid is a prerequisite to thera-peutic targeting of eosinophil recruitment. Galectin -9 is a potent chemoattractant for eosinophils, but its potential role in bullous pemphigoid is unknown. The aim of this study was to determine the expression levels of galectin-9 in serum and skin of patients with bullous pemphigoid. Galectin-9 levels were significantly elevated in serum of patients with bullous pemphigoid compared with age- and sex-matched controls, but did not correlate with disease activity assessed with the Bullous Pemphigoid Disease Area Index. Galectin-9 expression was also increased in lesional skin of patients with bullous pemphigoid, and was expressed predominantly in eosinophils, neutrophils and keratinocytes. In conclusion, these results support the notion that galectin-9 may play a role in the patho-genesis of bullous pemphigoid.

Diagnosis of Epidermolysis Bullosa Acquisita: Multicentre Comparison of Different Assays for Serum Anti-type VII Collagen Reactivity.

Epidermolysis bullosa acquisita is a pemphigoid disease characterized by autoantibodies against type VII collagen. This study compared the sensitivity and specificity of 6 diagnostic assays: type VII collagen non-collagenous domains enzyme-linked immunoassay (NC1/2 ELISA) (MBL, Nagoya, Japan); type VII collagen NC1 ELISA (Euroimmun, Lübeck, Germany); indirect immunofluorescence (IF) microscopy test based on the expression of recombinant NC1 in a human cell line (NC1 BIOCHIP®; Euroimmun); full-length recombinant type VII collagen ELISA; immunoblotting with full-length type VII collagen in the extract of human dermis; and immunoblotting with recombinant NC1. Immunoblotting with recombinant NC1 showed a sensitivity of 93.1% and specificity of 100%, follow-ed by NC1 BIOCHIP® (sensitivity, 89.1%; specificity, 100%), immunoblotting with human dermis (sensitivity, 87.1%; specificity 100%), NC1-ELISA (sensitivity 82.2%; specificity 98.6%), NC1/NC2 ELISA (sensitivity 88.1%; specificity 93.3%), and full-length type VII collagen ELISA (sensitivity 80.2%; specificity 93.8%).

Immunoglobulin and Complement Immunohistochemistry on Paraffin Sections in Autoimmune Bullous Diseases: A Systematic Review and Meta-analysis.

ABSTRACT: Immunohistochemistry (IHC) on formalin-fixed, paraffin-embedded tissue has been proposed as a potential tool in the diagnosis of autoimmune bullous diseases (AIBDs) in lieu of standard direct immunofluorescence (DIF) microscopy. To comprehensively determine the diagnostic accuracy of immunoglobulin and complement IHC for diagnosis of AIBDs, we conducted a systematic review and multivariate Bayesian model-based meta-analysis of the literature. Quality and heterogeneity assessment of studies was performed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist and the I2 index, respectively. Electronic searches using PubMed from April 1964 to July 2020 identified 14 articles meeting predetermined inclusion and exclusion criteria. Median sensitivities with 95% credible intervals in pemphigus and pemphigoid were 0.24 (0.01-0.89) and 0.22 (0.02-0.77) with immunoglobulin G (IgG), 0.77 (0.39-0.95) and 0.25 (0.02-0.85) with IgG4, 0.11 (0.02-0.32) and 0.86 (0.56-0.98) with C3d, and 0.84 (0.56-0.97) and 0.75 (0.37-0.94) with C4d, respectively. Specificities were 1.00 (0.00-1.00) with IgG, 0.98 (0.89-1.00) with IgG4, 0.99 (0.97-1.00) with C3d, and 0.99 (0.97-1.00) with C4d. The risk of bias and heterogeneity among studies was a serious problem, decreasing the level of evidence. Our work suggests that, in selected cases, paraffin-based IHC may be a helpful procedure to screen for AIBDs, especially when specialized laboratories and/or biopsy specimens for DIF do not exist. Nevertheless, more studies with a refined quality design are needed to explore the true usefulness of this diagnostic method in AIBDs.

A Mitochondrial Polymorphism Alters Immune Cell Metabolism and Protects Mice from Skin Inflammation.

Several genetic variants in the mitochondrial genome (mtDNA), including ancient polymorphisms, are associated with chronic inflammatory conditions, but investigating the functional consequences of such mtDNA polymorphisms in humans is challenging due to the influence of many other polymorphisms in both mtDNA and the nuclear genome (nDNA). Here, using the conplastic mouse strain B6-mtFVB, we show that in mice, a maternally inherited natural mutation (m.7778G > T) in the mitochondrially encoded gene ATP synthase 8 (mt-Atp8) of complex V impacts on the cellular metabolic profile and effector functions of CD4+ T cells and induces mild changes in oxidative phosphorylation (OXPHOS) complex activities. These changes culminated in significantly lower disease susceptibility in two models of inflammatory skin disease. Our findings provide experimental evidence that a natural variation in mtDNA influences chronic inflammatory conditions through alterations in cellular metabolism and the systemic metabolic profile without causing major dysfunction in the OXPHOS system.