Immunologic prediction of relapse in patients with pemphigus vulgaris (PV) in clinical remission

Antidesmoglein 1 and 3 serum IgG and positivity by direct immunofluorescence microscopy is associated with relapse in pemphigus in a prospective bicontinental study

Background

Prospective studies identifying immunological parameters that can predict clinical relapse in pemphigus are scarce.

Objective

To periodically assess immunological parameters in patients with pemphigus vulgaris and foliaceous in remission to understand immunological events preceding clinical relapse.

Methods

A total of 105 patients were included. Baseline assessment included direct immunofluorescence (DIF), serum IgG against desmoglein (Dsg) 1, IgG, IgG1, and IgG4 against Dsg 3, IgG against the extracellular domains 1 and 2 of Dsg 3, IgG against muscarinic (M3)-AchR, and peripheral CD19+CD27+ memory B cells/plasma cells, repeated every 3 months for up to 12 months or until clinical relapse. DIF was repeated at month 12 and on relapse.

Results

About 29 of 105 patients (28%) experienced a relapse. Longer duration of clinical remission, presence of pruritus and positive anti-Dsg1 at baseline correlated with higher relapse rates. Compared with the visit immediately preceding relapse, a significantly increased number of patients with positive anti-Dsg1 (38% vs 31.1%, P = .01), anti-Dsg3 (51.7% vs 41.4%, P = .01) and IgG positivity by DIF (85.7% vs 25%, P < .001) was observed at the time of relapse.

Conclusion

Regular monitoring of anti-Dsg 1 and anti-Dsg 3 serum levels and DIF positivity during the course of the disease in remission may predict relapse.

Direct immunofluorescence on plucked hair outer root sheath can predict relapse in pemphigus vulgaris

BACKGROUND

Prospective research is lacking on the utility of plucked hair outer root sheath direct immunofluorescence (ORS DIF) in the prediction of relapse in pemphigus vulgaris (PV) and the correlation of ORS DIF positivity with serum desmoglein antibody titers.

METHODS

We performed a prospective cohort study enrolling 80 PV patients in complete clinical remission at a tertiary care center in North India. Study participants underwent ORS DIF at baseline, which was repeated every 3 months. Skin biopsy DIF was done at study inclusion, repeated at 3 months, and upon clinical relapse. An antidesmoglein antibody titer was assessed concurrently with ORS DIF in a subset of patients. Patients on adjuvant therapy had their adjuvant therapy withdrawn either at the initial visit, at 3 months, or at a 6-month follow-up. Our objectives were to determine the association between positive ORS DIF and clinical relapse, the correlation between positive ORS DIF and skin biopsy DIF, and between positive ORS DIF and positive antidesmoglein antibody titers (when concurrently done).

RESULTS

Twenty-two patients (27.5%) had a clinical relapse. Baseline immunological markers significantly associated with relapse are ORS DIF positivity with IgG (16/36 [45.44%] P = 0.005) and C3 (12/29 [41.37%] P = 0.047) and greater intensity of baseline IgG and C3 positivity in ORS DIF (IgG, P = 0.002; C3, P = 0.033). Notably, a significant correlation was observed between baseline positive ORS DIF and skin biopsy DIF (IgG, ρ = 0.695; C3, ρ = 0.498). Positive ORS DIF strongly correlated with positive anti-Dsg3 antibody titers (φs = 0.815; P < 0.01). Early withdrawal of adjuvant immunosuppressant (within 3 months) (P = 0.007) and positive ORS DIF were also associated with relapse (P = 0.017).

CONCLUSION AND RELEVANCE

ORS DIF is a reliable predictor of PV clinical relapse and demonstrated robust correlations with skin biopsy DIF and antidesmoglein antibody titers. Periodic assessment of ORS DIF aids in determining new-onset positivity that heralds clinical relapse.

Consensus Based Indian Guidelines for the Management of Pemphigus Vulgaris and Pemphigus Foliaceous

Pemphigus is an autoimmune blistering disorder characterized by the presence of intraepidermal blisters and erosions, primarily affecting the mucosa and/or skin. There are no established Indian guidelines for the management of pemphigus, and Western guidelines cannot be directly applied due to differences in clinicodemographic profiles, comorbidities, and resource limitations. These guidelines aim to provide Indian dermatologists with evidence-based and consensus-driven recommendations for the management of pemphigus vulgaris (PV) and pemphigus foliaceous (PF), taking into account the unique challenges posed by the Indian healthcare setting. The guidelines focus on the comprehensive management of PV and PF, addressing diagnosis, treatment, monitoring, and follow-up. It is intended for dermatologists working in both outpatient and inpatient settings across India. The first draft of the guidelines was prepared by the writing group and then reviewed by 19 national experts in pemphigus management, including inputs from allied specialties. Areas with limited evidence or anticipated variation in recommendations were subjected to rounds of voting, with responses categorized as "strongly agree," "agree," "neutral," "disagree," or "strongly disagree." Suggestions were incorporated, and statements were revised until a mean agreement score of 4 or higher was reached across 16 key areas after four voting rounds. These guidelines offer a structured approach to managing pemphigus in India, addressing the need for region-specific recommendations that account for unique challenges such as resource constraints and specific comorbidities in Indian patients. They serve as a valuable resource for dermatologists treating pemphigus in a range of clinical settings.

IgG reactivity to different desmoglein-3 ectodomains in pemphigus vulgaris: novel panels for assessing disease severity

Introduction

Pemphigus vulgaris (PV) is an autoimmune disease characterized by IgG autoantibodies targeting desmoglein-3 (Dsg3), leading to blistering of mucous membranes and skin. Although commercial ELISA kits effectively diagnose PV, correlation with clinical phenotype remains unclear. This study assesses multiple panels for monitoring disease severity and activity by profiling IgG autoantibodies against Dsg3's various extracellular ectodomains.

Method

We designed and expressed different extracellular domains of Dsg3 in HEK293T cell line and developed 15 different ELISA panels, each using a single or multi ectodomains encompassing the entire extracellular region of Dsg3 to detect specific autoantibodies against the particular part of Dsg3.

Results

To validate our approach, we compared our ELISA panel for the full Dsg3 (EC1-5) against a commercial kit using 154 random serum samples from PV patients, demonstrating a strong correlation. For evaluation of IgG autoantibody profiles in our panels, 59 PV patients were included, along with 11 bullous pemphigoid patients, and 49 healthy controls. For all the included subjects, 15 predefined ELISA panels were tested. The IgG autoantibodies against EC1 were detected in 86% of patients with a positive full Dsg3 ectodomain (EC1-5) ELISA, with 26% against EC2, 14% for EC3, 29% for EC4, and 23% for EC5. Among the panels with multiple Dsg3 ectodomains, EC1-3 and EC1-4 were representative of the entire Dsg3 ectodomain in terms of ELISA positivity across all included patients. A significant correlation (P<0.05) was observed between ELISA optical density (OD) and Pemphigus Disease Area Index (PDAI) scores in five panels, EC1, EC2-3, EC2-5, and EC3-4 in addition to the full ectodomain. It suggests an association with disease severity. Interestingly, while the ELISA panel for the entire Dsg3 extracellular ectodomains did not differentiate disease phases, in three of our panels, including EC1, EC3-5, and EC2-5, ANOVA analysis showed a statistically significant difference between the groups of patients in remission, partial remission or persistent lesions, and those with active disease (new cases or relapse). Among these three panels, EC1 was the only one that showed a significant difference in the multiple comparisons analysis; patients in the active phase had higher levels of autoantibodies than those in 'partial remission or persistent lesions' and 'complete remission' groups.

Conclusion

The level of autoantibodies against EC1 was not only correlated with the full ectodomain but also associated with higher disease severity and active disease phase. This study indicates that a detailed autoantibody profile against Dsg3 ectodomains could serve as a marker for PV severity and activity which may potentially enhance early treatment initiation.

The human skin organ culture model as an optimal complementary tool for murine pemphigus models

Pemphigus is a severe autoimmune bullous disease of the skin and/or mucous membranes caused by autoantibodies that mainly target the adhesion proteins desmoglein (Dsg) 3 and/or Dsg1. Clinically, pemphigus is characterized by flaccid blistering, leading to severe water and electrolyte loss. Before the introduction of corticosteroid treatment, the disease turned out to be fatal in many cases. Despite recent therapeutic improvements, treatment of pemphigus patients is centred on prolonged systemic immunosuppression and remains challenging. Current drug development for pemphigus has a strong focus on disease-causing B cells and autoantibodies and, more recently, also on modulating autoantibody-induced tissue pathology and keratinocyte signalling. This drug development requires reliable pre-clinical model systems replicating the pathogenesis of the human disease. Among those are neonatal and adult mouse models based on the transfer of Dsg3, Dsg1/3 or Dsg1-specific autoantibodies. To reduce the number of animal experiments, we recently established a standardized human skin organ culture (HSOC) model for pemphigus. This model reproduces the clinical phenotype of autoantibody-induced tissue pathology in pemphigus vulgaris. For induction of blistering, a recombinant single-chain variable fragment (scFv) targeting both Dsg1 and 3 is injected into pieces of human skin (obtained from plastic surgeries). Further characterization of the HSOC model demonstrated that key morphologic, molecular and immunologic features of pemphigus are being replicated. Thus, the pemphigus HSOC model is an excellent alternative to pemphigus animal model systems that are based on the transfer of (auto)antibodies.

Taiwanese dermatological association (TDA) consensus for the management of pemphigus

Pemphigus is an uncommon but life-threatening autoimmune blistering disease characterized by the presence of antibodies against desmogleins. Without effective treatment, pemphigus can result in significant morbidity and mortality. Existing consensus statements on pemphigus management from international medical groups provide varying guidelines, especially on treatment. Thus, on January 4, 2020, a panel of seven dermatology experts from the Taiwanese Dermatological Association (TDA) and one rheumatology expert convened to develop a consensus for the management of pemphigus. These experts with extensive experience in pemphigus management were recommended by their respective teaching hospitals and primary care clinics in Taiwan and by the TDA. The meeting reviewed the available consensus statements from international dermatology groups, including the European Dermatology Forum (EDF), the European Academy of Dermatology and Venereology (EADV), and the International Bullous Diseases Consensus Group. Using these guidelines as a basis for discussion and consensus formulation, these experts formulated their consensus statement that provides practical, concise but comprehensive recommendations as to the diagnosis, treatment, and monitoring of pemphigus patients in Taiwan. This consensus serves as a clinical reference for physicians for the management of pemphigus in Taiwan or wherever it may be applicable.

Targeting therapy in pemphigus: Where are we now and where are we going?

Pemphigus is a heterogeneous group of autoimmune skin disorders characterized by blistering of the skin and mucosal membranes, potentially affecting the quality of life if left unchecked. The current mainstay of treatment is systemic corticosteroids and immunosuppressive agents. Nevertheless, long-term use of these drugs can easily cause infections and other life-threatening adverse reactions. Thus, currently, researchers are trying to develop new and safer therapeutic approaches. Specifically, targeted therapies to pathogenic immune pathways have been gradually introduced and used for the treatment of pemphigus or in clinical trials, such as monoclonal anti-CD20 antibody, BAFF inhibitor, BTK inhibitor, CAAR-T therapy, FcRn antagonist, and TNF-α inhibitor. In addition, IL-4Rα antibody, IL-17 blockade, mTOR pathway inhibitor, CTLA-4Ig, and p38 MAPK inhibitors are theoretically promising treatment for pemphigus. Here, we review the research progress on the mechanism of targeted therapies for pemphigus.

The Essential Role of microRNAs in Inflammatory and Autoimmune Skin Diseases-A Review

The etiopathogenesis of autoimmune skin diseases is complex and still not fully understood. The role of epigenetic factors is emphasized in the development of such diseases. MicroRNAs (miRNAs), a group of non-coding RNAs (ncRNAs-non-coding RNAs), are one of the important post-transcriptional epigenetic factors. miRNAs have a significant role in the regulation of the immune response by participating in the process of the differentiation and activation of B and T lymphocytes, macrophages, and dendritic cells. Recent advances in research on epigenetic factors have provided new insights into the pathogenesis and potential diagnostic and therapeutic targets of many pathologies. Numerous studies revealed a change in the expression of some microRNAs in inflammatory skin disorders, and the regulation of miRNA expression is a promising therapeutic goal. This review presents the state of the art regarding changes in the expression and role of miRNAs in inflammatory and autoimmune skin diseases, including psoriasis, atopic dermatitis, vitiligo, lichen planus, hidradenitis suppurativa, and autoimmune blistering diseases.

Autoantibodies against Desmoglein 1 and 3 in South Tunisian pemphigus

BACKGROUND

Desmoglein (Dsg) 1 and 3 are the 2 major autoantigens in pemphigus foliaceus (PF) and pemphigus vulgaris (PV).

AIM

We aimed to determine anti-Dsg1 and 3 Abs'usefulness in the diagnosis of pemphigus and to assess the correlation of these antibodies (Abs) with clinical phenotype and disease activity in south Tunisian patients.

METHODS

We retrospectively analyzed 131 samples from 82 patients (52 with PF and 30 with PV) during follow-up. Anti-Dsg1 and 3 Abs were measured by ELISA. Consecutive anti-Dsg1 and 3 Abs were correlated with disease activity. Receiver operating characteristics (ROC) curve were calculated to determine anti-Dsg1 and 3 Abs'cut-offs with optimal sensitivity and specificity for disease activity.

RESULTS

Anti-Dsg1 and 3 levels were associated to in PF and PV patients respectively (p<0,001). Anti-Dsg1 and 3 Ab were associated with skin (95%) and mucosal (60%) lesions, respectively. A significant decrease of anti-Dsg1 Abs was observed in patients with PF in clinical remission (36 ± 62 U/mL; (p=0,04). No correlation was found between anti-Dsg3 Abs and the course of mucosal lesions in PV (p=0,3). During follow-up, anti-Dsg1 Abs correlated with relapses (177 ±60 U/mL ; p=0,04). The 161,5 U/mL cut-off for anti-Dsg1 Abs provided 100% specificity and 86,4% sensitivity in PF disease activity. The 30,7U/mL cut-off for anti-Dsg3 provided 89,5% sensitivity and 100% specificity in PV.

CONCLUSIONS

High anti-Dsg3 Abs values are not always associated with PV disease activity. Anti-Dsg1 Abs showed a closer relationship with skin activity in PS and should be therefore taken into account in management of pemphigus patients.

Clinical and serological predictors of relapse in pemphigus: a study of 143 patients

BACKGROUND

Pemphigus is an autoimmune bullous disease mediated by autoantibodies targeting epithelial cell-cell adhesion molecules. Predictors of relapse have not yet been clearly identified.

AIMS

To identify factors at diagnosis and during follow-up that could be predictors of relapse.

METHODS

Clinical and immunopathological data at diagnosis, clinical remission and first relapse from patients with pemphigus vulgaris or foliaceus and at least a 36-month follow-up were collected retrospectively. Based on the autoantibody profile at diagnosis, three serological patient subsets were devised: (i) anti-desmoglein (Dsg)1-positive and anti-Dsg3-negative; (iii) anti-Dsg1-negative and anti-Dsg3-positive; and (iii) anti-Dsg1-positive and anti-Dsg3-positive.

RESULTS

Data from 143 patients were collected. No significant differences were found between relapsers (n = 90) and nonrelapsers (n = 53) for time to remission or for anti-Dsg1 and anti-Dsg3 titres at diagnosis and remission. In the analysis of all patients, a higher risk of relapse was found for a body surface area (BSA) score of 3 compared with BSA < 3 (OR = 3.30, 95% CI 1.17-9.28; P = 0.02) and for a positive titre of either anti-Dsg1 or anti-Dsg3 autoantibodies at remission compared with both being negative (OR = 2.42, 95% CI 1.21-4.85, P = 0.01). In patients who were anti-Dsg3-positive and anti-Dsg1-negative at diagnosis, failure to achieve anti-Dsg3 negativity at clinical remission was a significant predictor of relapse (OR = 7.89, 95% CI 2.06-30.21; P < 0.01). Similarly, failure to achieve anti-Dsg1 negativity at clinical remission was a significant predictor of relapse in patients with both anti-Dsg1 and anti-Dsg3 positivity at diagnosis (OR = 5.74, 95% CI 1.15-28.61; P = 0.03), but not in those who were anti-Dsg1-positive/anti-Dsg3-negative at diagnosis (OR = 1.08, 95% CI 0.27-4.30; P = 0.91).

CONCLUSION

Regardless of pemphigus subtype, autoantibody titre negativity at clinical remission in patients classified based on their anti-Dsg1 and anti-Dsg3 profile at diagnosis and BSA were useful tools in predicting relapse.

Current status and prospects for the diagnosis of pemphigus vulgaris

Introduction: Pemphigus vulgaris (PV) is an intraepidermal autoimmune bullous disease (AIBD) characterized by autoantibodies against desmosomal adhesion proteins, most commonly desmoglein (Dsg)3, leading to the suprabasal cleft formation and acantholysis.Areas covered: Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) studies display the intercellular deposition of IgG/C3 throughout the epidermis and presence of circulating autoantibodies respectively, as a net-like pattern. However, the target antigen remains unknown using immunofluorescence techniques. Thanks to the development of Dsg ELISA, using recombinant technology, circulating antibodies against Dsg1 and 3 could be detected sensitively. It is possible to differentiate PV from pemphigus foliaceus (PF) using this assay. BIOCHIP mosaic and multivariant ELISA are two novel serologic methods with the added value of the ability to screen several AIBDs simultaneously.Non-Dsg1/3 antigens are also involved in the pathogenesis of PV and investigated more deeply thanks to the protein microarrays technique. Additionally, patients with high values of anti-Dsg1/3 may be lesion-free, suggesting the presence of nonpathogenic autoantibodies.Expert opinion: Newer diagnostic methods to replace traditional techniques should possess high sensitivity and specificity and be widely available, noninvasive, and relatively cheap. The newly developed methods need to be further evaluated before being recommended for routine use.

Biologics in autoimmune bullous diseases: Current scenario

Autoimmune bullous diseases can be intraepidermal (pemphigus group of disorders) or subepidermal (pemphigoid group of disorders). The treatment of these disorders chiefly comprises corticosteroids and immunosuppressant adjuvants like azathioprine and mycophenolate mofetil. Autoantibodies are the main mediators of these diseases. Rituximab, a chimeric anti-CD20 monoclonal antibody targeting B-cells, has emerged as an excellent treatment option for refractory pemphigus vulgaris in the last decade. Since then, many new biologics have been proposed/explored for managing autoimmune bullous diseases. These hold potential for greater efficacy and lesser adverse effects than conventional immunosuppressants. In this review, we discuss the role of various biologics in the treatment of autoimmune bullous diseases, followed by a brief discussion on the drawbacks to their use and new developments in this area.

MicroRNAs in pemphigus and pemphigoid diseases

Autoimmune blistering diseases are a heterogenous group of dermatological disorders characterized by blisters and erosions of the skin and/or mucous membranes induced by autoantibodies against structural proteins of the desmosome or the dermal-epidermal adhesion complex including the hemidesmosome. They consist of the two major disease groups, pemphigus and pemphigoid diseases (PPDs). The diagnosis is based on clinical findings, histopathology, direct immunofluorescence, and detection of circulating autoantibodies. The pathogenesis is not fully elucidated, prognostic factors are lacking, and to date, there is no cure for PPDs. MicroRNAs (miRNAs) represent small, non-coding RNAs that play a pivotal role in the posttranscriptional regulation of gene expression. Their dysfunction was highlighted to play a significant role in the pathogenesis of various diseases. Even though a link between miRNAs and autoimmune blistering diseases had been suggested, the research of their involvement in the pathogenesis of PPDs is still in its infancy. miRNAs hold promise for uncovering new layers in the pathogenesis of PPDs, in order to improve diagnosis and also to develop potential therapeutic options. In the current article, we provide an overview regarding current knowledge of miRNAs in terms of complex pathogenesis of PPDs, and, also, their potential role as biomarkers, predictive factors and therapeutic targets.

Clinical and biological activity of rituximab in the treatment of pemphigus

B-cells are major effector cells in autoimmunity since they differentiate into plasmocytes that produce pathogenic auto-antibody such as anti-desmoglein antibodies in pemphigus patients. Major advances were obtained using whole B-cell depleting therapies including anti-CD20 antibodies in refractory pemphigus patients that lead to rituximab approval in pemphigus patients in EU and USA. This review summarizes the data supporting the efficacy of rituximab in pemphigus and provides an overview of the reported immunological changes underlying its therapeutic action. Short and long-term remission in pemphigus is explained by the removal of autoreactive B-cells involved in the production of pathogenic IgG auto-antibodies and by enhancement of the appearance of regulatory B-cells that could maintain long term immune tolerance.

Identification of clinical and immunological factors associated with clinical relapse of pemphigus vulgaris in remission

Background

Pemphigus vulgaris is a potentially fatal autoimmune epidermal blistering disease with a chronic and relapsing course. It is difficult to predict clinical relapse. Identification of clinical and immunological factors that are associated with early clinical relapse in a prospective study design may help in planning treatment for better maintenance of clinical remission.

Aim

The aim of our study was to identify clinical and immunological factors associated with clinical relapse within 9 months of study inclusion in patients with pemphigus vulgaris in clinical remission.

Methods

Forty consecutive consenting patients who had been diagnosed to have pemphigus vulgaris and were in clinical remission on minimal therapy or off therapy were included. The patients were followed up every 3 months until 9 months. Clinical factors considered relevant were recorded at the beginning of the study. Immunological factors such as CD19+ B-cell count and CD19+CD27+ memory B cells/plasma cell count in peripheral blood were assessed at baseline [anti-desmoglein (Dsg) 1 and 3 titers were first assessed at 3 months, not at baseline] and repeated every 3 months, until 9 months or clinical relapse whichever was earlier. Direct immunofluorescence (DIF) of skin biopsy specimen was performed at study initiation and again at the time of clinical relapse or study completion, whichever occurred earlier. All patients completed the study.

Results

Of 40 patients, 11 (27.5%) experienced relapse as per definition, while 29 (72.5%) remained in complete remission. Clinical relapse during study duration was significantly more common in those who had onset of disease in oral mucosa [odds ratio (OR), 10.71; 95% confidence interval (CI) 1.21-94.86, P = 0.02], pruritus (OR 8.4; 95% CI 1.76-40.02, P = 0.01), and extensive cutaneous involvement during previous disease activity (OR 7.36; 95% CI 1.34-40.55, P = 0.03) and also pruritus during remission (P = 0.004). Immunological factors found to be significantly associated with early clinical relapse were raised CD19+ B-cell count at baseline (OR 7.84; 95% CI 1.39 - 53.41, P = 0.01), immunoglobulin G (OR 4.85; 95% CI 1.09-23.44, P = 0.04), and C3 (OR 20.33; 95% CI 3.02-199.5, P < 0.001) positivity in the intercellular space of the epidermis on DIF at study onset and rising anti-Dsg 3 antibody titers (OR 19.96; 95% CI 1.85- 310.9, P = 0.03).

Limitations

Limited sample size, short follow-up duration, and inability to perform anti-Dsg enzyme linked immunosorbent assay for all the patients at all the time points of assessment are limitations of this study.

Conclusion

Immunological relapse can be determined before clinical relapse, so that treatment can be restarted/modified and clinical remission can be maintained.

Immune serological diagnosis of pemphigus

Pemphigus is a rare autoimmune blistering disease which manifests with painful erosions and blisters of the skin and mucosa. This disorder is caused by autoantibodies attacking desmosomal proteins, necessary for cell-cell contact stability and epidermal integrity. Desmoglein (Dsg) 1 and Dsg3 are the two major target antigens in pemphigus. Yet, many other target proteins, which have been described over the years, seem to be involved in the loss of epidermal integrity. Clinical examination, combined to serological advances and detection of targeted antigens, permitted to differentiate among several pemphigus subtypes, in which pemphigus vulgaris and pemphigus foliaceus are the most common. Nowadays, serological analysis in pemphigus is a fundamental step of the diagnostic algorithm. This is based on analysis of clinical symptoms, histopathological examination of lesional skin, detection of tissue bound and circulating antibodies by direct and indirect immunofluorescence, and determination of target antigens either by enzyme-linked immunosorbent essay (ELISA) or by western blot analysis. A correct and exhaustive diagnostic algorithm is fundamental to characterize pemphigus subtypes, which lastly permits to adopt a correct treatment approach. Moreover, quality and quantity of circulating antibodies in patient's sera deliver important information regarding clinical course, disease severity and treatment response; thus, relevantly affecting physician's decision. To facilitate this process, "easy-to-perform" diagnostic kits with high sensitivity and specificity are being commercialized. In this review, we focus on available methods and established assays to correctly detect circulating autoantibodies in pemphigus. Moreover, we discuss subtype specific serological peculiarities in the five most relevant subtypes (pemphigus vulgaris, pemphigus foliaceus, pemphigus vegetans, paraneoplastic pemphigus and intercellular IgA dermatosis (also called as IgA pemphigus).

Estimated cut-off values for pemphigus severity classification according to pemphigus disease area index (PDAI), autoimmune bullous skin disorder intensity score (ABSIS), and anti-desmoglein 1 autoantibodies

BACKGROUND

Pemphigus is a potentially fatal disease if left untreated. Valid scoring systems and defined cut-off values for classification of patients would help with better management through specified pharmaceutical and non-pharmaceutical treatments.

METHODS

In this study, pemphigus patients who were receiving immunosuppressive treatments and had recent disease relapse were recruited for examination of pemphigus disease area index(PDAI), autoimmune bullous skin disorder intensity score (ABSIS), physician global assessment (PGA), autoimmune bullous disease quality of life (ABQoL), anti-desmoglein 1 (anti-Dsg1), and anti-Dsg3 autoantibody titers from December-2017 to February-2018. Cut-off values were estimated using model-based clustering classification and the 25th and 75th percentiles approach, performed separately for the exclusive cutaneous, exclusive mucosal, and mucocutaneous groups.

RESULTS

In the 109 included patients, the 25th and 75th percentiles cut-offs were 6.2 and 27 for PDAI score, and 4 and 29.5 for ABSIS score. The model-based analysis resulted in two groups (cut-point:15) for PDAI score, and three groups (cut-points:6.4 and 31.5) for ABSIS score. The groups were significantly different for the PDAI, ABSIS, PGA, and ABQoL values. Based on anti-Dsg1 autoantibody values, the model-based analysis cut-point was 128 and the 25th and 75th percentiles cut-offs were 98 and 182. Anti-Dsg3 autoantibody values did not differentiate between pemphigus severity classes.

CONCLUSIONS

Estimated cut-off values based on the anti-Dsg1 level, PDAI, and ABSIS scoring systems could be used to classify patients into different severity grades for better management and prognosis.

Pemphigus

Pemphigus consists of a group of rare and severe autoimmune blistering diseases mediated by pathogenic autoantibodies mainly directed against two desmosomal adhesion proteins, desmoglein (Dsg)1 and Dsg3 (also known as DG1 and DG3), which are present in the skin and surface-close mucosae. The binding of autoantibodies to Dsg proteins induces a separation of neighbouring keratinocytes, in a process known as acantholysis. The two main pemphigus variants are pemphigus vulgaris, which often originates with painful oral erosions, and pemphigus foliaceus, which is characterised by exclusive skin lesions. Pemphigus is diagnosed on the basis of either IgG or complement component 3 deposits (or both) at the keratinocyte cell membrane, detected by direct immunofluorescence microscopy of a perilesional biopsy, with serum anti-Dsg1 or anti-Dsg3 antibodies (or both) detected by ELISA. Corticosteroids are the therapeutic mainstay, which have recently been complemented by the anti-CD20 antibody rituximab in moderate and severe disease. Rituximab induces complete remission off therapy in 90% of patients, despite rapid tapering of corticosteroids, thus allowing for a major corticosteroid-sparing effect and a halved number of adverse events related to corticosteroids.

Serological Diagnosis of Autoimmune Bullous Skin Diseases

Autoimmune bullous dermatoses (AIBD) encompass a variety of organ-specific autoimmune diseases that manifest with cutaneous and/or mucosal blisters and erosions. They are characterized by autoantibodies targeting structural proteins of the skin, which are responsible for the intercellular contact between epidermal keratinocytes and for adhesion of the basal keratinocytes to the dermis. The autoantibodies disrupt the adhesive functions, leading to splitting and blister formation. In pemphigus diseases, blisters form intraepidermally, whereas in all other disease types they occur subepidermally. Early identification of autoimmune bullous dermatoses is crucial for both treatment and prognosis, particularly as regards tumor-associated disease entities. The diagnosis is based on clinical symptoms, histopathology, direct immunofluorescence to detect antibody/complement deposits, and the determination of circulating autoantibodies. The identification of various target antigens has paved the way for the recent development of numerous specific autoantibody tests. In particular, optimized designer antigens and multiplex test formats for indirect immunofluorescence and ELISA have enhanced and refined the laboratory analysis, enabling highly efficient serodiagnosis and follow-up. This review elaborates on the current standards in the serological diagnostics for autoimmune bullous dermatoses.

Short-term clinical and serological follow-up with conventional and conformational anti-desmoglein antibodies in treatment-naïve and previously treated patients with pemphigus vulgaris after receiving rituximab

Background

Pemphigus vulgaris (PV) is a blistering, life-threatening autoimmune disease. Ethylenediaminetetraacetic acid (EDTA)-treated desmoglein (Dsg) enzyme-linked immunosorbent assay (ELISA) has recently been suggested to detect nonpathogenic antibodies. Rituximab (RTX) is now considered a first-line treatment for PV.

Objective

The primary and secondary aims were to evaluate anti-Dsg and EDTA-treated anti-Dsg ELISA and clinical response before and 3 months after RTX in treatment-naïve and previously treated patients, respectively. In addition, we compared the short-term efficacy of RTX between these groups.

Methods

Seventy-five patients with PV who received RTX (500 mg weekly for 4 weeks or 1000 mg 2 weeks apart) and prednisolone were followed for 3 months. Thirty-seven treatment-naïve newly diagnosed (group A) and 38 relapsed patients (group B) were included. Disease activity was scored with the Pemphigus Disease Area Index (PDAI). Clinical response was also assessed. Serum samples were collected at two points and examined for anti-Dsg1/3 and EDTA-treated anti-Dsg1/3. Conformational anti-Dsg values were calculated by subtracting EDTA-treated from conventional anti-Dsg values.

Results

The correlation of conventional and conformational anti-Dsg values was perfect (correlation coefficient > 0.98; p < .001) at every time point for both anti-Dsgs. There was no difference with regard to PDAI and anti-Dsg values between the two groups at baseline. The frequency of responders was significantly higher in group A (100%) than in group B (89%; p = .006). Three patients relapsed, and five patients had persistent disease activity in group B. After 3 months, conventional and conformational anti-Dsg values were significantly higher in group B compared with group A (anti-Dsg3: p = .017 and .021, respectively; anti-Dsg1: p = .014 and .016, respectively). Total and scalp PDAI were significantly lower in group A than in group B (p = .042 and .016, respectively).

Conclusion

EDTA-treated anti-Dsg ELISA had no added value. Using RTX as first-line treatment in patients with PV appears to be associated with better clinical response and immunologic profile than delayed treatment in the short term.

Immunological methods for the diagnosis of oral mucosal diseases

Immunological methods, which have been widely used in autoimmune blistering diseases (AIBDs) of the oral mucosa, can also be adopted as auxiliary diagnostic tools in oral lichen planus (OLP) and discoid lupus erythematosus (DLE). AIBDs, characterized by autoantibodies against structural proteins of keratinocytes or the basement membrane zone, clinically present as blisters and erosions of the oral mucosa. When atypical lesions occur, OLP or DLE may be confused with AIBDs. The improvement of diagnostic accuracy is necessary due to the significant differences in treatment and prognosis among these diseases. A variety of immunological methods are used for qualitative and quantitative detection of target antigens and autoantibodies. These methods can evaluate efficacy of treatment, monitor diseases and guide treatment decisions. In this review, we discuss the application of immunofluorescence, biochemical tests, and protein microarrays for AIBDs, OLP and DLE, as well as the differential diagnostic methods using immunological tests.

Clinical and immunological features of pemphigus relapse

BACKGROUND

More than half of patients with pemphigus experience relapse during the disease course. The risk factors and clinical and immunological characteristics of relapse remain largely unclear.

OBJECTIVES

To elucidate the risk factors and clinical features of pemphigus relapse.

METHODS

We carried out a retrospective review of the clinical records of 42 cases of pemphigus at a single centre.

RESULTS

Sixty-two per cent of patients experienced relapse, usually when oral prednisolone was tapered to around 0·1 mg kg^-1 . In mucocutaneous pemphigus vulgaris (mcPV), the initial doses (mean ± SD) of prednisolone were significantly lower in patients with relapse (0·78 ± 0·24 mg kg^-1 ) than in those without relapse (1·01 ± 0·01 mg kg^-1 ). At relapse, mcPV shifted to mucosal dominant PV (mPV; 40%), pemphigus foliaceus (PF) (20%) or 'other' (20%). In contrast, relapsing mPV and PF had the same clinical phenotypes as the initial phenotypes. Patients with both anti-desmoglein (Dsg)1 and anti-Dsg3 antibodies at onset had recurrence with anti-Dsg3 antibodies alone (40%), with both anti-Dsg1 and anti-Dsg3 antibodies (30%), with anti-Dsg1 antibody alone (20%) or were subthreshold (10%).

CONCLUSIONS

mcPV shows transitions in clinical phenotype and autoantibody profile at relapse. At least 1 mg kg^-1 daily of prednisolone, especially for patients with mcPV, and prudent tapering around 0·1 mg kg^-1 may lead to better outcomes.

A prospective study comparing patients with early and late relapsing pemphigus treated with rituximab

BACKGROUND

Rituximab (RTX) is an effective therapy for patients with pemphigus; however, the therapy does not prevent relapse.

OBJECTIVES

To compare early relapsing patients (before 12 months) and late relapsing patients (after 24 months) following RTX therapy.

METHOD

In this prospective study, 19 patients were enrolled (14 with pemphigus vulgaris and 5 with pemphigus foliaceus). The baseline disease score, autoantibody levels, and percentage of CD20⁺ cells of patients with pemphigus were measured. Patients received 1 cycle of RTX and were followed for 26 months.

RESULTS

Among early relapsing patients (n = 5), the time to relapse was 6 to 11 months. Among late relapsing patients (n = 6), the time to relapse was 24 to 26 months. A significant difference was observed in the mean baseline anti-desmoglein 1 (DSG1) index between early relapsing (705.72) and late relapsing patients (210.4) (P = .0014). A significant negative correlation was found between the baseline anti-DSG1 index and time to relapse (r = -0.777, P = .00009).

LIMITATIONS

The small number of patients with pemphigus foliaceus.

CONCLUSIONS

Because patients with high baseline anti-DSG1 indices relapsed earlier, it may be important to follow these patients closely for the initial 12 months after RTX therapy. These patients may require a maintenance RTX dose during the first 12 months after RTX therapy.