Tag Archives: pemphigus vulgaris

Pemphigus vulgaris (PV) is an autoimmune disease in which the body’s immune system develops antibodies to two of its own proteins, the desmogleins DSG1 and DSG3 that help maintain the integrity of the skin. The immune attack causes painful blisters on the skin and mucus membranes that can lead to infections. Current therapies are geared towards suppressing the entire immune system, but this is problematic as it causes many side effects and leaves the patient vulnerable to infection.

To identify better therapeutic targets, researchers at the Institute for Research in Biomedicine in Bellinzona, Switzerland, identified the portions of DSG1 and DSG3 that are targeted by antibodies. In the study, published this month in the Journal of Clinical Investigation, Antonio Lanzavecchia and colleagues collected immune cells from PV patients and isolated the antibodies to determine which ones were involved in PV. By studying the antibodies, they were able to identify regions of DSG3 that are the primary target of the immune sysm. These findings could help with new ways to diagnose and treat PV.

Full article available at: http://www.medicalnewstoday.com/releases/249883.php

Pemphigus vulgaris (PV) is an autoimmune blistering disease of skin and mucous membranes caused by autoantibodies to the desmoglein (DSG) family proteins DSG3 and DSG1, leading to loss of keratinocyte cell adhesion. To learn more about pathogenic PV autoantibodies, we isolated 15 IgG antibodies specific for DSG3 from 2 PV patients. Three antibodies disrupted keratinocyte monolayers in vitro, and 2 were pathogenic in a passive transfer model in neonatal mice. The epitopes recognized by the pathogenic antibodies were mapped to the DSG3 extracellular 1 (EC1) and EC2 subdomains, regions involved in cis-adhesive interactions. Using a site-specific serological assay, we found that the cis-adhesive interface on EC1 recognized by the pathogenic antibody PVA224 is the primary target of the autoantibodies present in the serum of PV patients. The autoantibodies isolated used different heavy- and light-chain variable region genes and carried high levels of somatic mutations in complementary-determining regions, consistent with antigenic selection. Remarkably, binding to DSG3 was lost when somatic mutations were reverted to the germline sequence. These findings identify the cis-adhesive interface of DSG3 as the immunodominant region targeted by pathogenic antibodies in PV and indicate that autoreactivity relies on somatic mutations generated in the response to an antigen unrelated to DSG3.

Pemphigus vulgaris (PV) is a life-threatening autoimmune blistering disease of skin and mucous membranes caused by autoantibodies that bind to the cadherin-type cell-cell adhesion molecules desmoglein 3 (DSG3) and DSG1, the main constituents of desmosomes, and cause the loss of keratinocyte cell adhesion. The critical role of autoantibodies in PV pathogenesis is supported by the observations that the disease activity correlates with anti-DSG3 antibody titers , that newborns of mothers with active PV exhibit blisters caused by the placental transfer of maternal antibodies, and that pemphigus-like lesions are induced in neonatal mice by passive transfer of anti-DSG3 IgG from PV patients.

In the skin, DSG3 is mainly expressed in the basal and suprabasal layers, while DSG1 is predominantly expressed in the upper epidermal layers. In contrast, in noncornified stratified epithelia, such as the oral mucosa, DSG3 is highly expressed throughout the epithelium, while DSG1 is expressed at a much lower level. The differential expression pattern of DSG1 and DSG3 is responsible for clinical variants of pemphigus: antibodies to DSG3 are present in the mucosal form, while antibodies to both DSG3 and DSG1 are associated with mucocutaneous lesions.

DSG3 is a calcium-binding membrane glycoprotein with an extracellular domain comprising 5 distinct subdomains (EC1–EC5), and it is synthesized as proprotein, which is processed in the Golgi apparatus by removal of a propeptide before transporting to the cell surface. The cleavage of the propeptide occurs upstream of a conserved tryptophan residue in the EC1 subdomain, unmasking residues critical for the formation of homophilic interactions with DSG3 on opposing cells. Several studies have shown that polyclonal antibodies in PV serum react primarily with the aminoterminus of DSG3 in the EC1 and EC2 subdomains (amino acids 1–161).

The isolation of pathogenic mAbs is instrumental for addressing questions as to the mechanism that induces the autoreactive response and drives blister formation in PV patients. Amagai and coworkers isolated from an active mouse model of PV a pathogenic antibody, AK23, which causes loss of cell adhesion by binding to the EC1 subdomain of DSG3 that is involved in the formation of the trans-adhesive interface. A number of human anti-DSG pathogenic and nonpathogenic mAbs were isolated as single-chain variable-region fragments (scFvs) from a PV patient . Similarly to the AK23 mAb, the pathogenic activity of these human antibodies was mapped to the aminoterminal region of EC1, which is masked by the propeptide . Taken together, the human and mouse data suggest that pathogenic antibodies bind primarily to EC1 and disrupt the keratinocyte adhesion by interfering with the trans-adhesive interface of DSG3.

In this study, we isolated from 2 PV patients several IgG autoantibodies that bind DSG3. These antibodies carried high levels of somatic mutations that were required for binding to DSG3. The epitopes recognized by 3 pathogenic antibodies were mapped to the EC1 and EC2 subdomains in regions that are expected to be involved in cis-adhesive interactions. This region was found to be the primary target of serum autoantibodies in PV patients. These results identify the cis-adhesive interface as the immunodominant region targeted by pathogenic antibodies in PV and suggest that autoreactivity relies on somatic mutations triggered by an unrelated antigen.

Full article Available at: http://www.jci.org/articles/view/64413

We report a case of neutropenic ulceration in a 42-year-old woman receiving azathioprine for pemphigus vulgaris. She developed multiple indolent ulcers involving the nose, neck, and back, after about 6-8 weeks following commencement of azathioprine 50 mg daily. The ulcers were large, disfiguring, dry, and with basal necrotic slough. They were painless and did not discharge pus. The absolute neutrophil count was severely depressed initially, but normalized following azathioprine withdrawal. Swab culture revealed colonization with Klebsiella pneumoniae and the ulcers healed with local debridement, treatment with imipenem, and topical application of mupirocin. However, nasal disfigurement persisted. Neutropenic ulceration is known to be associated with azathioprine therapy but we report this case because of the unusual presentation-indolent cutaneous ulcers. Early recognition of the problem and drug withdrawal can prevent complications like disfigurement.

Neutropenia is characterized by an abnormally low number of neutrophils in the blood. Neutrophils normally comprise 45-75% of circulating white blood cells, and neutropenia is diagnosed when the absolute neutrophil count falls to <1500/ μL. Slowly developing neutropenia often goes undetected and is generally discovered when the patient develops sepsis or localized infections.

There are many causes of neutropenia, and immunosuppressants are a common iatrogenic cause. Azathioprine is an immunosuppressant drug that is being used for nearly 50 years now in organ transplantation and in diseases with suspected autoimmune etiology. Dermatologists use azathioprine as a steroid-sparing agent in various dermatoses such as psoriasis, immunobullous diseases, photodermatoses, and eczematous disorders. [1] The drug has been used in ulcerative autoimmune disorders such as Crohn’s disease and pyoderma gangrenosum. On the other hand, it has also been implicated as a cause of ulceration associated with neutropenia. [2] Most reports of neutropenic ulceration document involvement of the buccal mucosa and oral cavity.  We report a case of multiple severe cutaneous ulcers associated with long-term azathioprine use in a patient with pemphigus vulgaris.

Full article available at: http://www.ijp-online.com/article.asp?issn=0253-7613;year=2012;volume=44;issue=5;spage=646;epage=648;aulast=Laha

Dichorionic diamniotic twins were born at 37 weeks of gestation by cesarean section to a 34-year-old primigravid Japanese woman because the first twin was in breech presentation. The mother had been diagnosed with pemphigus vulgaris prior to her pregnancy. In addition to a high antidesmoglein 3 autoantibody titer, flaccid bullae and erosions on both of the twins’ lips and in their oral cavities at 13 days of age led to the diagnosis of neonatal pemphigus vulgaris. This case highlights the need for awareness that pemphigus vulgaris may not occur immediately after birth.

http://onlinelibrary.wiley.com/doi/10.1111/j.1525-1470.2012.01828.x/abstract;jsessionid

Associations between blood groups and several diseases are observed in the literature. Some of these have scientific support suggesting a rationale, statistical relation. The association between ABO groups with several malignancies, hypercholesterolemia, thrombosis, myocardial infarction, duodenal ulcer, infections, and autoimmune diseases is reported.  Pemphigus vulgaris (PV), a rare autoimmune, blistering disease, related to autoantibodies mainly directed to desmogleins, which lead to loss of keratinocyte adhesion.  The association between ABO groups and pemphigus has been proposed but not fully demonstrated. Shahkar et al., concluded the non-existent relationship between blood groups and the development of PV. The authors carried out a case-control study that showed there is no real association between blood groups and PV, in contrast to the work of Grob and Inderbitzin  and Altobella.  The authors determined that the presence of a particular blood group, in patients with the disease, does not vary significantly with “healthy” population distribution, which is very important because the relationship between blood groups and skin diseases has been controversial and not yet fully elucidated or explained clearly.

In 2007, Valikhani et al.,  showed not only that the ABO and Rhesus blood groups not have a particular distribution in the PV, other than the population, but no such relationship with any of the known variants of pemphigus, at least in Iran, suggesting the authors to conduct a study involving other areas of global demographic.

In Mexico, we conducted a similar study in a tertiary referral center for specialized dermatology consultation. We obtained the ABO and Rhesus blood groups of patients with PV in a period between January 2002 and October 2009, being our hospital a center that collects patients from different parts of Mexico and even South America.

We selected 70 charts of patients with PV. No differences in the presence of a particular blood group in patients with the disease were found (P=0.65). We sought to evaluate if any ABO group correlates with the clinical outcome (body surface area affected) of the patients studied. There were no positive or negative correlation between ABO groups and clinical outcome in PV (P=0.752)

We conclude, there is no association between ABO and Rhesus blood groups with PV, demonstrated by observing no differences between the presentations of a specific blood group in the disease. Moreover, there is no association between any ABO groups with the clinical outcome in PV.

Tirado-Sánchez A, Ponce-Olivera RM. Lack of relationship between blood groups and clinical outcome (body surface area affected) in patients with pemphigus vulgaris. Indian J Dermatol [serial online] 2012 [cited 2012 Sep 12];57:411-2. Available from: http://www.e-ijd.org/text.asp?2012/57/5/411/100513

Background:  Pemphigus vulgaris (PV) is an autoimmune blistering skin disorder characterized by the presence of suprabasal acantholysis and autoantibodies against desmoglein 3. There are two different clinical forms: mucocutaneous (MCPV) or mucosal (MPV). However, it is not clear how PV lesions in oral, ear, nose and throat (OENT) areas produced by the very dynamic of the anatomical structures involved in the functions of the aerodigestive tract. Objectives:  To investigate the pattern of OENT manifestations in PV, and their relationship with physiological traumatic mechanisms in stratified squamous epithelium structures. Patients:  A prospective analysis of 40 patients diagnosed with MCPV (22 patients) or MPV (18 patients) was carried out in the University Clinic of Navarra. OENT manifestations were evaluated in all patients endoscopically. OENT involvement was divided into anatomical areas. Results:  The most frequent symptom was pain, mainly on oral mucosa (87,5%). Buccal mucosa (90%), posterior wall of pharynx (67.5%), upper edge of epiglottis (85%) and nasal vestibule (70%) were the areas most frequently affected in the OENT mucosa. These localizations were related to physiological traumatic mechanisms in polystratified squamous epithelium structures. Conclusions:  OENT endoscopy should be included in the examination of all PV patients. To know the most frequent localizations of active lesions on OENT mucosa in PV will help us to interpreter more efficiently the findings from OENT endoscopy. Also, information related to traumatic physiological mechanisms on OENT areas must be offered to patients in order to avoid the appearance of new active PV lesions.
PMID: 22716123 [PubMed – as supplied by publisher] (Source: The British Journal of Dermatology)
from MedWorm: Pemphigus http://www.medworm.com/index.php?rid=6310669&cid=c_297_12_f&fid=37668&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2FPubMed%2F22716123%3Fdopt%3DAbstract

Background:  Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are potentially fatal blistering diseases caused by autoantibodies targeting desmoglein adhesion proteins. Previous studies have shown an IgG4>IgG1 predominance of anti-desmoglein antibodies in pemphigus; however, no studies have examined total serum IgG4 levels in pemphigus. IgG4 is induced by chronic antigen stimulation, which could occur with persistent skin blistering and potentially elevate the total serum IgG4 relative to other IgG subclasses in pemphigus patients.

Objectives:  The primary aim of the study was to quantitate total and desmoglein-specific IgG subclasses in pemphigus patients.

Methods:  IgG subclasses and desmoglein-specific IgG1 and IgG4 were quantitated in PV, PF, and age-matched normal sera using a subclass ELISA. The effectiveness of IgG4 depletion in blocking PV IgG pathogenicity was determined using a keratinocyte dissociation assay.

Results:  Desmoglein-specific antibodies comprised a median of 7.1% and 4.2% of total IgG4 in PV and PF patients, with 8-fold and 4-fold enrichment in IgG4 versus IgG1. Total serum IgG4, but not other IgG subclasses, was enriched in PV and PF patients compared to age-matched controls (p=0.004 and p=0.005, respectively). IgG4 depletion of PV sera reduced pathogenicity in a keratinocyte dissociation assay and showed that affinity-purified IgG4 is more pathogenic than other serum IgG fractions.

Conclusions:  Desmoglein-specific autoantibodies are significantly enriched in IgG4, which may explain the enrichment of total serum IgG4 in some pemphigus patients. By preferentially targeting autoimmune rather than beneficial immune antibodies, IgG4-targeted therapies may offer safer treatment options for pemphigus.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2133.2012.11144.x/abstract

This report describes the clinical presentations and treatment responses of three children with PV, as confirmed according to histology and indirect immunofluorescence studies. In all three cases, oral prednisone used in conjunction with mycophenolate mofetil (MMF) resulted in complete clinical remission, during which all pharmacotherapy was successfully discontinued. Resolution of the skin and mucosal blistering tended to occur quickly with prednisone, and after initiation of treatment with MMF, discontinuation of all pharmacotherapy was achieved within a range of 10 to 30 months in the three patients. One patient experienced a recurrence of genital lesions 19 months after discontinuation of therapy, but the condition remitted within 2 weeks with topical corticosteroid therapy. At the time of this report, the duration of complete remission ranged from 6 to 19 months. In summary, combination therapy with prednisone and MMF for pediatric PV appears to be a safe and effective approach that is associated with durable remission.

http://onlinelibrary.wiley.com/doi/10.1111/j.1525-1470.2012.01730.x/abstract

Several studies have tried to determine the relationship between auto-antibodies against the acetylcholine receptor and the development of pemphigus vulgaris. In this study, we observed that antibody levels against the acetylcholine receptor are mildly elevated in pemphigus vulgaris (PV), and significantly correlate with disease severity on the initial diagnosis and during follow up. However, it is not clear if these antibodies are just an epiphenomenon or a potential trigger of the known pathogenic process in PV.

 

Source: http://www.ncbi.nlm.nih.gov/pubmed/22630584?dopt=Abstract

Background:  Pemphigus vulgaris (PV) is an autoimmune blistering skin disorder characterized by the presence of suprabasal acantholysis and autoantibodies against desmoglein 3. There are two different clinical forms: mucocutaneous (MCPV) or mucosal (MPV). However, it is not clear how PV lesions in oral, ear, nose and throat (OENT) areas produced by the very dynamic of the anatomical structures involved in the functions of the aerodigestive tract.

Objectives:  To investigate the pattern of OENT manifestations in PV, and their relationship with physiological traumatic mechanisms in stratified squamous epithelium structures.

Patients:  A prospective analysis of 40 patients diagnosed with MCPV (22 patients) or MPV (18 patients) was carried out in the University Clinic of Navarra. OENT manifestations were evaluated in all patients endoscopically. OENT involvement was divided into anatomical areas.

Results:  The most frequent symptom was pain, mainly on oral mucosa (87,5%). Buccal mucosa (90%), posterior wall of pharynx (67.5%), upper edge of epiglottis (85%) and nasal vestibule (70%) were the areas most frequently affected in the OENT mucosa. These localizations were related to physiological traumatic mechanisms in polystratified squamous epithelium structures.

Conclusions:  OENT endoscopy should be included in the examination of all PV patients. To know the most frequent localizations of active lesions on OENT mucosa in PV will help us to interpreter more efficiently the findings from OENT endoscopy. Also, information related to traumatic physiological mechanisms on OENT areas must be offered to patients in order to avoid the appearance of new active PV lesions.

 

Source: Study of Oral, Ear, Nose, and Throat Involvement…