Restoring immune tolerance in pemphigus vulgaris.

Intravenous immunoglobulin (IVIg), a preparation of polyclonal serum IgG pooled from numerous blood donors, has been used for nearly three decades and is proving to be an efficient treatment for many autoimmune blistering diseases, including pemphigus vulgaris (PV). Despite its widespread use and therapeutic success, its mechanisms of action are not completely understood. Some of its anti-inflammatory and immunomodulatory actions have been studied. In this study, the authors present a twenty-year follow-up of 21 patients with clinical and immunopathological confirmed PV, treated with IVIg as monotherapy, according to an established published protocol. IVIg therapy produced long-term sustained, clinical, serological, and immunopathological remission. For 20 y, these patients received no drugs and experienced no disease. This observation suggests that there was the establishment of immune balance or restoration of immune regulation in these PV patients. Twelve (57%) patients experienced no relapse during follow-up. Six (29%) patients experienced a relapse due to acute stress or post-coronavirus infection and/or vaccination. Reinstitution of IVIg resulted in prompt sustained recovery. Three (14.2%) patients, in clinical and serological remission, died due to unrelated causes. No severe adverse effects from IVIg were documented in all 21 patients. The simultaneous or sequential anti-inflammatory and immunomodulatory effects of IVIg may have influenced the long-term clinical remission observed. This study provides a human prototype to examine the pathophysiology of autoimmunity and a model to study immune regulation and mechanisms that can facilitate restoring immune tolerance.

Single-Cell Transcriptomes and Immune Repertoires Reveal the Cell State and Molecular Changes in Pemphigus Vulgaris.

The etiology and pathogenesis of pemphigus vulgaris (PV) entail intricate interactions between immune cells and epithelial cells. However, the specific subtypes of immune cells involved in PV, along with their respective roles, remain elusive. Likewise, the precise functions and mechanisms by which glucocorticoids affect cell types within the disease context require further elucidation. To address these knowledge gaps, we performed 5' single-cell RNA sequencing, combined with V(D)J enrichment on buccal mucosal lesions and peripheral blood samples from treatment-naive patients with PV, in conjunction with post-treatment peripheral blood samples obtained after oral prednisone treatment. Our findings suggest that the IL-1α signaling pathway, myeloid APCs, inflammatory CD8+ resident memory T cells, and dysfunctional CD4+ regulatory T cells are involved in the pathogenesis of PV. Part of these findings were validated by immunohistochemical assays and multiplex immunofluorescence assays. Furthermore, our results highlight the significant impact of prednisone treatment on monocytes and mucosal-associated invariant T cells while revealing a limited effect on CD4+ regulatory T cells. Additionally, we present the CDR3 amino acid sequence of BCR related to PV disease and investigate the characteristics of TCR/BCR clonotypes. In conclusion, our study provides a comprehensive understanding of PV, particularly focusing on the mucosal-dominant type, and sheds light on the effects of glucocorticoids within the PV context. These insights hold promise for the development of new therapeutic strategies in this autoimmune disorder.

Meeting report - Desmosome dysfunction and disease: Alpine desmosome disease meeting.

Desmosome diseases are caused by dysfunction of desmosomes, which anchor intermediate filaments (IFs) at sites of cell-cell adhesion. For many decades, the focus of attention has been on the role of actin filament-associated adherens junctions in development and disease, especially cancer. However, interference with the function of desmosomes, their molecular constituents or their attachments to IFs has now emerged as a major contributor to a variety of diseases affecting different tissues and organs including skin, heart and the digestive tract. The first Alpine desmosome disease meeting (ADDM) held in Grainau, Germany, in October 2022 brought together international researchers from the basic sciences with clinical experts from diverse fields to share and discuss their ideas and concepts on desmosome function and dysfunction in the different cell types involved in desmosome diseases. Besides the prototypic desmosomal diseases pemphigus and arrhythmogenic cardiomyopathy, the role of desmosome dysfunction in inflammatory bowel diseases and eosinophilic esophagitis was discussed.

Single-cell sequencing reveals distinct immune cell features in cutaneous lesions of pemphigus vulgaris and bullous pemphigoid.

Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are two common subtypes of autoimmune bullous disease (AIBD). The key role of circulating autoreactive immune cells contributing to skin damage of AIBD has been widely recognized. Nevertheless, the immune characteristics in cutaneous lesions remain unclear. Here, we performed single-cell RNA sequencing (scRNA-seq) and single-cell VDJ sequencing (scRNA-seq) to generate transcriptional profiles for cells and T/B cell clonetype in skin lesions of BP and PV. We found that the proportions of NK&T, macrophages/ dendritic cells, B cells, and mast cells increased in BP and PV lesions. Then, BP and PV cells constituted over 75% of all myeloid cell subtypes, CD4+ T cell subtypes and CD8+ T cell subtypes. Strikingly, CD8+ Trm was identified to be expanded in PV, and located in the intermediate state of the pseudotime trajectory from CD8+ Tm to CD8+ Tem. Interestingly, CD8+ Tem and CD4+ Treg highly expressed exhaustion-related genes, especially in BP lesions. Moreover, the enhanced cell communication between stromal cells and immune cells like B cells and macrophages/ dendritic cells was also identified in BP and PV lesions. Finally, clone expansion was observed in T cells of BP and PV compared with HC, while CD8+ Trm represented the highest ratio of hyperexpanded TCR clones among all T cell subtypes. Our study generally depicts a large and comprehensive single-cell landscape of cutaneous lesions and highlights immune cell features in BP and PV. This offers potential research targets for further investigation.

Rituximab versus Mycophenolate Mofetil in Patients with Pemphigus Vulgaris.

BACKGROUND: Rituximab and mycophenolate mofetil are used to treat pemphigus vulgaris, but they have not been adequately compared in clinical trials. METHODS: In a randomized, controlled trial, we assigned patients with moderate-to-severe pemphigus vulgaris in a 1:1 ratio to receive intravenous rituximab (1000 mg on days 1, 15, 168, and 182) or oral mycophenolate mofetil (2 g per day), in addition to an oral glucocorticoid administered on the same tapering schedule in the two groups. The primary end point was sustained complete remission at week 52, defined as the healing of lesions with no new active lesions, as reflected by a Pemphigus Disease Area Index (PDAI) activity score of 0 (on a scale of 0 to 250, with higher scores indicating greater disease severity), for at least 16 weeks without the use of glucocorticoids. Secondary end points were the cumulative dose of glucocorticoids, the number of disease flares, and the change from baseline in the score on the Dermatology Life Quality Index (DLQI; scores range from 0 to 30, with higher scores indicating greater impairment). RESULTS: Of the 135 patients who underwent randomization, 67 were assigned to receive rituximab and 68 to receive mycophenolate mofetil. The primary outcome was assessed in the modified intention-to-treat population: 62 patients in the rituximab group and 63 in the mycophenolate mofetil group. The median PDAI activity scores at baseline were 22.7 in the rituximab group and 18.3 in the mycophenolate mofetil group. At week 52, sustained complete remission was observed in 25 patients (40%) in the rituximab group and in 6 (10%) in the mycophenolate mofetil group (difference, 31 percentage points; 95% confidence interval [CI], 15 to 45; P<0.001). The mean cumulative glucocorticoid dose during the 52-week treatment period was 3545 mg in the rituximab group and 5140 mg in the mycophenolate mofetil group (difference, -1595 mg; 95% CI, -2838 to -353; P<0.001). There were 6 disease flares in the rituximab group and 44 in the mycophenolate mofetil group (adjusted rate ratio, 0.12; 95% CI, 0.05 to 0.29; P<0.001). The mean change in DLQI score was -8.87 points and -6.00 points, respectively (difference, -2.87 points; 95% CI, -4.58 to -1.17; P = 0.001). Serious adverse events occurred in 15 of 67 patients (22%) in the rituximab group and in 10 of 68 (15%) in the mycophenolate mofetil group. CONCLUSIONS: Rituximab was superior to mycophenolate mofetil in producing sustained complete remission at 52 weeks in patients with pemphigus vulgaris. Rituximab resulted in a greater reduction in glucocorticoid use than mycophenolate mofetil, but more patients in the rituximab group had serious adverse events. Further trials are needed to determine the comparative efficacy and safety of rituximab and mycophenolate mofetil beyond 52 weeks of treatment. (Funded by F. Hoffmann-La Roche; PEMPHIX ClinicalTrials.gov number, NCT02383589.).

Integrative single-cell analysis reveals distinct adaptive immune signatures in the cutaneous lesions of pemphigus.

Pemphigus, an autoimmune bullous disease affecting the skin and mucosal membranes, is primarily driven by anti-desmoglein (Dsg) autoantibodies. However, the underlying immune mechanisms of this disease remain largely elusive. Here, we compile an unbiased atlas of immune cells in pemphigus cutaneous lesions at single-cell resolution. We reveal clonally expanded antibody-secreting cells (ASCs) that exhibit variable hypermutation and accumulation of IgG4 class-switching in their immunoglobulin genes. Importantly, pathogenic Dsg-specific ASCs are localized within pemphigus lesions and can evolve from both Dsg-autoreactive and non-binding precursors. We observe an altered distribution of CD4+ T cell subsets within pemphigus lesions, including an imbalance of Th17/Th2 cells. Significantly, we identify a distinct subpopulation of Th17 cells expressing CXCL13 and IL-21 within pemphigus lesions, implying its pivotal role in B cell recruitment and local production of autoantibodies. Furthermore, we characterize multiple clonally expanded CD8+ subpopulations, including effector GMZB+ and GMZK+ subsets with augmented cytotoxic activities, within pemphigus lesions. Chemokine-receptor mapping uncovers cell-type-specific signaling programs involved in the recruitment of T/B cells within pemphigus lesions. Our findings significantly contribute to advancing the understanding of the heterogeneous immune microenvironment and the pathogenesis of pemphigus cutaneous lesions, thereby providing valuable insights for potential therapeutic interventions in this disease.

Immune interplay from circulation to local lesion in pemphigus pathogenesis.

Pemphigus, a potentially lethal autoimmune skin disease, is mediated by desmoglein-specific antibodies, manifesting cutaneous and mucosal blisters and erosions. The interaction between multiple immune counterparts contributes to the progress of pemphigus. Currently, the emergence of bioinformatic analysis enables investigators to gain a global picture of the pemphigus immune network, based on the exhaustive pedigree annotation of multiple subsets. T helper subsets dominate the landscape as mentioned previously, and innate immune cells have been involved as well. Of particular interests is which phenotype of T cells orchestrates the autoimmune process and chronic inflammation in a certain condition. In this review, the circulatory and peripheral immune cells and cytokine components constituting the immune microenvironment are separately discussed to provide a perspective on pemphigus pathogenesis, with particular reference to insights provided by the bioinformation technique.

Alterations of circulating free fatty acids in patients with pemphigus vulgaris.

Free fatty acids (FFA) have gained research interest owing to their functions in both local and systemic immune regulation. Changes in the serum levels of anti-inflammatory short chain fatty acids (SCFA), primarily derived from the gut microbiota, and pro-inflammatory medium (MCFA) and long (LCFA) chain fatty acids, derived from either the gut microbiota or the diet, have been associated with autoimmunity. Circulating FFA were retrospectively analysed by a gas chromatography-mass spectrometry method in the serum of 18 patients with pemphigus vulgaris (PV) at the baseline and 6 months (n = 10) after immunosuppressive treatments, and 18 healthy controls (HC). Circulating FFA were correlated with the Pemphigus Disease Area Index (PDAI) and serum concentrations of interferon-gamma (IFN-γ), Interleukin (IL)-17A, IL-5, IL-10 and IL-21. Principal Component analysis computed on FFA abundances revealed significant differences in the profile of SCFA (p = 0,012), MCFA (p = 0.00015) and LCFA (p = 0,035) between PV patients and HC, which were not significantly changed by immunosuppressive treatments. PV patients showed a significantly lower serum concentration of propionic (p < 0.0005) and butyric (p < 0.0005) acids, SCFA with anti-inflammatory functions, while hexanoic (p < 0.0005) and hexadecanoic (p = 0.0006) acids, pro-inflammatory MCFA and LCFA respectively, were over-represented. Treatments induced a significant decrease of hexanoic (p = 0.035) and a further increase of hexadecanoic (p = 0.046) acids. Positive correlations emerged between IFN-γ and acetic acid (Rho = 0.60), IFN-γ and hexanoic acid (Rho = 0.46), IL-5 and both hexadecanoic acid (Rho = 0.50) and octadecanoic acid (Rho = 0.53), butyric acid and PDAI (Rho = 0.53). PV was associated with a remarked imbalance of circulating FFA compared to HC. The serum alterations of SCFA, MCFA, and LCFA may contribute to promoting inflammation in PV. Deeper insights into the immunomodulatory functions of these molecules may pave the way for personalized dietary interventions in PV patients.

Pulmonary interstitial lesions in pemphigus mouse model: Verifying pemphigus may not be only limited to skin and mucosa.

Interstitial lung disease (ILD) has been identified as a prevalent complication and significant contributor to mortality in individuals with pemphigus. In this study, a murine model of pemphigus was developed through the subcutaneous administration of serum IgG obtained from pemphigus patients, allowing for an investigation into the association between pemphigus and ILD. Pulmonary interstitial lesions were identified in the lungs of a pemphigus mouse model through histopathology, RT-qPCR and Sircol assay analyses. The severity of these lesions was found to be positively associated with the concentration of IgG in the injected serum. Additionally, DIF staining revealed the deposition of serum IgG in the lung tissue of pemphigus mice, indicating that the subcutaneous administration of human IgG directly impacted the lung tissue of the mice, resulting in damage. This study confirms the presence of pulmonary interstitial lesions in the pemphigus mouse model and establishes a link between pemphigus and ILD.

Local neutrophil and eosinophil extracellular traps formation in pyodermatitis pyostomatitis vegetans.

Pyodermatitis pyostomatitis vegetans is a rare inflammatory condition, affecting the skin and/or mucous membrane. Some cases include both skin and mucous involvement, whereas others develop either skin or mucous lesions only. The typically affected areas are the scalp, face, trunk and extremities, including the flexural areas and umbilicus. Clinical features show erosive granulomatous plaques, keratotic plaques with overlying crusts and pustular lesions. Among mucous lesions, oral mucosa is most frequently involved, and gingival erythema, shallow erosions, cobblestone-like papules on the buccal mucosa or upper hard palate of the oral cavity are also observed. Some of the lesions assume a 'snail track' appearance. Although there are several similarities between pyodermatitis pyostomatitis vegetans and other diseases, that is pyoderma gangrenosum, pemphigus vegetans and pemphigoid vegetans, the histopathological features of pyodermatitis pyostomatitis vegetans are unique in that epidermal hyperplasia, focal acantholysis and dense inflammatory infiltrates with intraepidermal and subepidermal eosinophilic microabscesses are observed. Direct immunofluorescence findings are principally negative. Activated neutrophils are supposed to play an important role in the pathogenesis of pyodermatitis pyostomatitis vegetans. The expression of IL-36 and neutrophil extracellular traps (NETs) was observed in the lesional skin, and additionally, eosinophil extracellular traps (EETs) was detected in pyodermatitis pyostomatitis vegetans. A possible pathogenic role of NETs and EETs in the innate immunity and autoinflammatory aspects of pyodermatitis pyostomatitis vegetans was discussed.

Beyond the skin: B cells in pemphigus vulgaris, tolerance and treatment.

Pemphigus vulgaris (PV) is a rare autoimmune bullous disease characterized by blistering of the skin and mucosa owing to the presence of autoantibodies against the desmosome proteins desmoglein 3 and occasionally in conjunction with desmoglein 1. Fundamental research into the pathogenesis of PV has revolutionized its treatment and outcome with rituximab, a B-cell-depleting therapy. The critical contribution of B cells to the pathogenesis of pemphigus is well accepted. However, the exact pathomechanism, mechanisms of onset, disease course and relapse remain unclear. In this narrative review, we provide an overview of the fundamental research progress that has unfolded over the past few centuries to give rise to current and emerging therapies. Furthermore, we summarize the multifaceted roles of B cells in PV, including their development, maturation and antibody activity. Finally, we explored how these various aspects of B-cell function contribute to disease pathogenesis and pave the way for innovative therapeutic interventions.

Pemphigus vulgaris (PV) is a rare autoimmune disease, in which the immune system attacks itself and causes blisters on the skin and inside the mouth. This happens because the body mistakenly attacks specific proteins (called desmosomes) that keep the skin together. Globally, this disease affects anywhere from 0.5 to 16.1 people per million, often older than 50 years. PV is life-threatening when left untreated. From carrying out research as far back as the 1700s, we have made significant strides in understanding PV. For example, research has led to a new treatment with the antibody rituximab, which works by eliminating the cells of the immune system that attack desmosomes (called B cells). However, after therapy is completed, the disease often returns because the same troublesome B cells reappear. There are multiple places that are involved when the body attacks desmosomes. The problems range from the bone marrow where the B cells are made and selected to the ways these cells change as they move around the body. It takes a rare combination of these changes to switch from a normal immune system to one that causes PV. Clinicians and researchers are currently developing new treatment options to better target this skin disease. We want to emphasize that research should continue to uncover how the disease works because a better understanding promotes the development of new therapies, and perhaps even a cure. This is vital, because PV can significantly lower the quality of life of people living with this skin disease.

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.

Acute myeloid leukemia with paraneoplastic pemphigus successfully treated with a personalized antileukemic and immunosuppressive strategy.

Bullous pemphigoid (BP) is a rare blistering disease often considered a primary sign of a paraneoplastic syndrome. Retrospective studies have established its link with hematological malignancies, particularly lymphoproliferative disorders. Here, we present what we believe to be the inaugural case of successful simultaneous management of BP and de novo acute myeloid leukemia (AML) in a 28-year-old male patient. Given the rarity and severity of both conditions, our treatment strategy aimed to maximize efficacy by combining immunosuppressive therapy (initially plasmapheresis with high-dose corticosteroids, followed by anti-CD20 monoclonal antibody and intravenous immunoglobulins 2 g/m2) with lymphodepleting antileukemic chemotherapy utilizing Fludarabine (FLAG-IDA induction regimen). Following diagnosis, considering the patient's youth and the concurrent presence of two rare and potentially life-threatening diseases, we opted for an aggressive treatment. Upon achieving complete morphological remission of AML with measurable residual disease (MRD) negativity, despite incomplete resolution of BP, we proceeded with high-dose cytarabine consolidation followed by peripheral stem cell harvest and autologous stem cell transplantation (ASCT). Our conditioning regimen for ASCT involved Bu-Cy with the addition of anti-thymocyte globulins. At day + 100 post-ASCT, bone marrow evaluation confirmed morphological remission and MRD negativity. Meanwhile, BP had completely resolved with normalization of BP180 antibody levels.

Autoimmune blistering disorders and cardiovascular risks: A population-based cohort study.

BACKGROUND: Autoimmune blistering disorders (ABDs) might elevate cardiovascular risk, but studies are lacking. OBJECTIVE: The objective of this study was to examine if ABDs elevate the risk of atherosclerotic cardiovascular disease, heart failure, arrhythmia, venous thromboembolism, and cardiovascular death. METHODS: A population-based cohort of Danish patients with ABD (≥18 years of age) diagnosed during 1996-2021 (n = 3322) was compared with an age- and sex-matched comparison cohort from the general population (n = 33,195). RESULTS: Compared with the general population, patients with ABDs had higher 1-year risks of atherosclerotic cardiovascular disease (3.4% vs 1.6%), heart failure (1.9% vs 0.7%), arrhythmia (3.8% vs 1.3%), venous thromboembolism (1.9% vs 0.3%), and cardiovascular death (3.3% vs 0.9%). The elevated risk persisted after 10 years for all outcomes but arrhythmia. The hazard ratios associating ABDs with the outcomes during the entire follow-up were 1.24 (1.09-1.40) for atherosclerotic cardiovascular disease, 1.48 (1.24-1.77) for heart failure, 1.16 (1.02-1.32) for arrhythmia, 1.87 (1.50-2.34) for venous thromboembolism, and 2.01 (1.76-2.29) for cardiovascular death. The elevated cardiovascular risk was observed for both pemphigus and pemphigoid. LIMITATIONS: Our findings might only generalize to patients with ABDs without prevalent cardiovascular diseases. CONCLUSION: Patients with ABDs had an elevated cardiovascular risk compared with age- and sex-matched controls.

IgM to IgG Class Switching Is a Necessary Step for Pemphigus Phenotype Induction in Desmoglein 3-Specific B Cell Receptor Knock-in Mouse.

Pemphigus vulgaris is an autoimmune blistering disease caused by IgG targeting desmoglein 3 (Dsg3), an adhesion molecule of keratinocytes. Anti-Dsg3 IgG production is prevented in healthy individuals, but it is unclear how Dsg3-specific B cells are regulated. To clarify the immunological condition regulating Dsg3-specific B cells, a pathogenic anti-Dsg3 Ig (AK23) knock-in mouse was generated. AK23 knock-in B cells developed normally without undergoing deletion or acquiring an anergic phenotype in vivo. The knock-in B cells showed Ca2+ influx upon IgM cross-linking and differentiated into AK23-IgG+ B cells after LPS and IL-4 stimulation in vitro that induced a pemphigus phenotype after adoptive transfer into Rag2 -/- mice. However, the knock-in mouse itself produced AK23-IgM but little IgG without blisters in vivo. Dsg3 immunization and skin inflammation caused AK23-IgG production and a pemphigus phenotype in vivo. Furthermore, Fcgr2b deficiency or haploinsufficiency spontaneously induced AK23-IgG production and a pemphigus phenotype with poor survival rates in AK23 knock-in mice. To assess Fcgr2b involvement in Ig class-switch efficiency, postswitch transcripts of B cells were quantified and significantly higher in Fcgr2b -/- and Fcgr2b +/- mice than wild-type mice in a gene dose-dependent manner. Finally, RNA sequencing revealed reduced expression of FCGR2B and FcγRIIB-related genes in patient B cells. These results indicated that Dsg3-specific B cells do not spontaneously perform pathogenic class switching in vivo, and pemphigus phenotype induction was prevented under normal conditions. Attenuated FcγRIIB signaling is also one of the drivers for pathogenic class switching and is consistent with immunological features identified from clinical samples. This study unveiled a characteristic immune state silencing autoreactive B cells in mice.

Co-occurrence of oral pemphigus vulgaris and herpes simplex virus infection in a young patient with Crohn's disease: report of a rare case of oral lesions during anti-TFN alpha and immunomodulator therapy.

BACKGROUND: Pemphigus vulgaris (PV) is a potentially life-threatening mucocutaneous autoimmune disease that affects desmoglein-1 and desmoglein-3, leading to intraepithelial vesiculobullous lesions. In the oral mucosa, PV lesions can mimic other diseases such as mucous membrane pemphigoid, other forms of pemphigus, recurrent aphthous stomatitis, erythema multiforme, Stevens-Johnson syndrome, and virus-induced ulcers like herpes simplex virus (HSV), making diagnosis challenging. The co-occurrence of PV with Crohn's disease is rare and predominantly seen in younger patients. The therapeutic mainstay for both PV and Crohn's disease usually involves systemic corticosteroids combined with immunosuppressants and immunobiological drugs. Literature indicates that the use of these drugs, particularly TNF-alpha inhibitors, for managing autoimmune diseases like Crohn's can potentially induce other autoimmune diseases known as autoimmune-like syndromes, which include episodes of lupus-like syndrome and inflammatory neuropathies. There are few cases in the literature reporting the development of PV in individuals with CD undergoing infliximab therapy. CASE REPORT: A young female with severe Crohn's disease, treated with the TNF-alpha inhibitor infliximab, developed friable pseudomembranous oral ulcerations. Histopathological and immunofluorescence analyses confirmed these as PV. The treatment included clobetasol propionate and low-level photobiomodulation, which resulted in partial improvement. The patient later experienced severe intestinal bleeding, requiring intravenous hydrocortisone therapy, which improved both her systemic condition and oral lesions. Weeks later, new ulcerations caused by herpes virus and candidiasis were identified, leading to treatment with oral acyclovir, a 21-day regimen of oral nystatin rinse, and photodynamic therapy, ultimately healing the oral infections. To manage her condition, the gastroenterologists included methotrexate (25 mg) in her regimen to reduce the immunogenicity of infliximab and minimize corticosteroid use, as the patient was in remission for Crohn's disease, and the oral PV lesions were under control. CONCLUSION: Young patients with Crohn's disease should be referred to an oral medicine specialist for comorbidity investigation, as oral PV and opportunistic infections can arise during immunosuppressive therapy. The use of TNF-alpha inhibitors in patients treated for inflammatory bowel disease, such as Crohn's, should be carefully evaluated for potential side effects, including oral PV.

Positive Herpesvirus IgG Antibodies in Lung Cancer Patients Finally Proved as Drug-induced Pemphigus.

BACKGROUND: Herpesvirus IgG antibody positivity can be a lifelong burden of disease replication and reinfection or recent viruses can be reactivated and play an important role in the diagnosis and monitoring of herpesvirus [1]. However, sometimes serum IgG antibody positivity is of limited help in determining the onset of disease. We reported a case of herpesvirus IgG antibody positive in a patient with lung cancer who was initially misdiagnosed as herpes simplex and later confirmed drug-induced pemphigus (DIP) by histological and immunofluorescence studies. METHODS: Appropriate laboratory tests, enzyme-linked immunosorbent assay (ELISA), immunofluorescence and histological tests were performed for diagnosis. RESULTS: In lung cancer patients who were positive for herpesvirus IgG antibodies, were initially misdiagnosed as herpes simplex and eventually confirmed by histological and immunofluorescence examinations as DIP. CONCLUSIONS: Positive herpesvirus IgG antibody is not a specific manifestation of herpesvirus infection. For patients with unexplained skin blisters, we should improve histological examinations as soon as possible to clarify the type of lesion.

Cytoskeletal anchorage of different Dsg3 pools revealed by combination of hybrid STED/SMFS-AFM.

Desmoglein 3 (Dsg3) is a desmosomal cadherin mediating cell adhesion within desmosomes and is the antigen of the autoimmune blistering skin disease pemphigus vulgaris. Therefore, understanding of the complex desmosome turnover process is of high biomedical relevance. Recently, super resolution microscopy was used to characterize desmosome composition and turnover. However, studies were limited because adhesion measurements on living cells were not possible in parallel. Before desmosomal cadherins are incorporated into nascent desmosomes, they are not bound to intermediate filaments but were suggested to be associated with the actin cytoskeleton. However, direct proof that adhesion of a pool of desmosomal cadherins is dependent on actin is missing. Here, we applied single-molecule force spectroscopy measurements with the novel single molecule hybrid-technique STED/SMFS-AFM to investigate the cytoskeletal anchorage of Dsg3 on living keratinocytes for the first time. By application of pharmacological agents we discriminated two different Dsg3 pools, only one of which is anchored to actin filaments. We applied the actin polymerization inhibitor Latrunculin B to modify the actin cytoskeleton and the PKCα activator PMA to modulate intermediate filament anchorage. On the cellular surface Dsg3 adhesion was actin-dependent. In contrast, at cell-cell contacts, Dsg3 adhesion was independent from actin but rather is regulated by PKC which is well established to control desmosome turn-over via intermediate filament anchorage. Taken together, using the novel STED/SMFS-AFM technique, we demonstrated the existence of two Dsg3 pools with different cytoskeletal anchorage mechanisms.

Sexual quality of life in patients with pemphigus: A case-control study.

BACKGROUND: Pemphigus, an autoimmune blistering disease that affects the skin and mucous membranes, significantly impairs the quality of life (QoL) of affected individuals. While there are a variety of QoL measurement tools available for assessing this disease, there is a lack of studies that specifically evaluate the sexual QoL of patients with pemphigus. OBJECTIVES: This case-control study aims to investigate the impact of the disease on sexual activity as well as its overall effect on QoL. MATERIALS AND METHODS: Fifty pemphigus patients, who were referred to the Dermatology Department at the University Hospital of Brescia in the period March 2019-September 2021, completed several QoL surveys, including the 36-item Short Form Health survey (SF-36), the 12-Item General Health Questionnaire (GHQ-12), the Autoimmune Bullous Disease Quality of Life (ABQOL) and either the International Index of Erectile Function (IIEF) or the Female Sexual Function Index (FSFI). The severity of the disease was assessed using the Pemphigus Disease Area Index (PDAI). Differences in QoL surveys between the case and control groups were analysed using either the t-test or the Wilcoxon-Mann-Whitney test. The correlation between QoL surveys in pemphigus patients and disease severity were analysed using Spearman's coefficient (r). RESULTS: The results revealed a marked impairment in overall QoL among patients with pemphigus compared to the healthy control subjects. Significant differences were observed in various domains of QoL, including physical health, mental well-being, social functioning and, notably, sexual health. Furthermore, disease severity as evaluated by the PDAI showed correlations with specific aspects of health status, and disease-specific QoL demonstrated associations with nearly all domains of health status. No significant correlations were found between sexual activity, mucosal involvement or steroid therapy and PDAI scores or disease-specific QoL measures. CONCLUSION: These findings emphasize the significant impact of pemphigus on patients' well-being, with particular attention to the impaired sexual activity.

Pemphigus Vulgaris Successfully Treated With Bromocriptine.

Pemphigus vulgaris (PV) is an autoimmune blistering skin condition primarily treated with immunosuppressive agents. We describe a case of PV successfully treated with nonconventional treatment, bromocriptine mesylate. Bromocriptine has been used in human trials showing beneficial therapeutic effects in managing autoimmune conditions. The results from experimental trials and the low toxicity of bromocriptine in comparison with immunosuppressive agents form a solid rationale for investigating its role in controlling PV.  J Drugs Dermatol. 2024;23(3):     doi:10.36849/JDD.7720e.