The distribution of immunoglobulins and the C3 component of complement in multiple biopsies from the uninvolved and perilesional skin in pemphigus

Pemphigus Vulgaris and Bullous Pemphigoid of the Upper Aerodigestive Tract: A Review Article and Novel Approaches to Management

BACKGROUND

Autoimmune bullous diseases are rare conditions characterized by blistering of the skin and mucous membranes. The 2 commonest forms are pemphigus vulgaris and bullous pemphigoid. The oral cavity or oropharynx may be the initial site of presentation or often the only site involved.

SUMMARY

These conditions are often misdiagnosed or overlooked leading to poorer patient outcomes. Due to the chronic nature of these conditions and the systemic effects of treatment, there is a significant associated morbidity and mortality. As such, an understanding of the fundamentals of autoimmune bullous diseases is vital to those working in otolaryngology. The mainstay of management in both conditions is topical and systemic corticosteroids. There is also a role for immunomodulating and non-steroidal anti-inflammatory drugs as adjunct or alternative therapies. Surgical intervention may be required to protect the airway. Often multimodality treatment is required involving multidisciplinary input from otolaryngologists, oral surgeons, dermatologists, and rheumatologists. This review article will highlight the aetiology, pathology, clinical features, investigations, and management of both pemphigus vulgaris and bullous pemphigoid including recent advances in management.

The optimal oral biopsy site for diagnosis of mucous membrane pemphigoid and pemphigus vulgaris

BACKGROUND

Accepted 'standard practice' for the diagnosis of immunobullous disease is a perilesional sample for direct immunofluorescence (DIF).

OBJECTIVES

To compare diagnostic outcomes of a normal buccal punch biopsy (NBPB) with a perilesional biopsy (PLB) for mucous membrane pemphigoid (MMP) and pemphigus vulgaris (PV).

METHODS

A retrospective analysis of 251 DIF-positive patients with MMP and 77 DIF-positive patients with PV was undertaken. Parameters analysed included the intraoral sites of involvement and histopathological, DIF and indirect immunofluorescence (IIF) findings.

RESULTS

For MMP, PLB was positive in 134 of 143 (93·7%) samples, compared with 129 of 144 (89·6%) by NBPB. The diagnostic sensitivities for PLB (81%, 39 of 48) and NBPB (77%, 37 of 48) among 48 patients who underwent both techniques were not significantly different (P = 0·62). In gingival-only MMP, PLB was positive in 63 of 69 (91%) and NBPB was positive in 63 of 75 (84%). For multisite MMP, PLB was positive in 71 of 74 (96%) and NBPB was positive in 66 of 69 (96%). In gingival-only MMP, biopsies from reflected alveolar mucosa in 17 consecutive patients were positive in 17 of 17 cases (100%). For PV, PLB was positive in 42 of 43 (98%), compared with 42 of 42 (100%) by NBPB. Histopathology was diagnostic in 93 of 134 (69·4%) cases of MMP and 38 of 41 (93%) cases of PV. IIF was positive in 126 of 197 (64·0%) MMP and 68 of 74 (92%) PV patient sera.

CONCLUSIONS

In the largest series of combined oral DIF results in patients with MMP and PV, we have shown that NBPB is equivalent to PLB for the diagnosis of PV and multisite MMP, and is more sensitive than both histology and IIF. What's already known about this topic? The variation in sensitivity of oral biopsy sites for direct immunofluorescence (DIF) in the diagnosis of oral MMP and PV has not been studied in detail in large series of patients. Biopsy can be challenging due to difficult access and fragility of the oral mucosa. The diagnostic biopsy technique is therefore critical. What does this study add? We have shown that a normal buccal punch biopsy (NBPB) from uninvolved oral mucosa is as sensitive as a perilesional biopsy (PLB) for diagnosis of oral PV, and superior to serology and histology. For multisite MMP, NBPB is equivalent to PLB and is more sensitive than serology and histology. The oral punch biopsy technique on uninvolved buccal mucosa tissue is a simple and safe practical method for diagnosing oral PV and MMP.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

Monopathogenic vs multipathogenic explanations of pemphigus pathophysiology

This viewpoint highlights major, partly controversial concepts about the pathogenesis of pemphigus. The monopathogenic theory explains intra-epidermal blistering through the "desmoglein (Dsg) compensation" hypothesis, according to which an antibody-dependent disabling of Dsg 1- and/or Dsg 3-mediated cell-cell attachments of keratinocytes (KCs) is sufficient to disrupt epidermal integrity and cause blistering. The multipathogenic theory explains intra-epidermal blistering through the "multiple hit" hypothesis stating that a simultaneous and synchronized inactivation of the physiological mechanisms regulating and/or mediating intercellular adhesion of KCs is necessary to disrupt epidermal integrity. The major premise for a multipathogenic theory is that a single type of autoantibody induces only reversible changes, so that affected KCs can recover due to a self-repair. The damage, however, becomes irreversible when the salvage pathway and/or other cell functions are altered by a partnering autoantibody and/or other pathogenic factors. Future studies are needed to (i) corroborate these findings, (ii) characterize in detail patient populations with non-Dsg-specific autoantibodies, and (iii) determine the extent of the contribution of non-Dsg antibodies in disease pathophysiology.

Critical Role of the Neonatal Fc Receptor (FcRn) in the Pathogenic Action of Antimitochondrial Autoantibodies Synergizing with Anti-desmoglein Autoantibodies in Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a life-long, potentially fatal IgG autoantibody-mediated blistering disease targeting mucocutaneous keratinocytes (KCs). PV patients develop pathogenic anti-desmoglein (Dsg) 3 ± 1 and antimitochondrial antibodies (AMA), but it remained unknown whether and how AMA enter KCs and why other cell types are not affected in PV. Therefore, we sought to elucidate mechanisms of cell entry, trafficking, and pathogenic action of AMA in PV. We found that PVIgGs associated with neonatal Fc receptor (FcRn) on the cell membrane, and the PVIgG-FcRn complexes entered KCs and reached mitochondria where they dissociated. The liberated AMA altered mitochondrial membrane potential, respiration, and ATP production and induced cytochrome c release, although the lack or inactivation of FcRn abolished the ability of PVIgG to reach and damage mitochondria and to cause detachment of KCs. The assays of mitochondrial functions and keratinocyte adhesion demonstrated that although the pathobiological effects of AMA on KCs are reversible, they become irreversible, leading to epidermal blistering (acantholysis), when AMA synergize with anti-Dsg antibodies. Thus, it appears that AMA enter a keratinocyte in a complex with FcRn, become liberated from the endosome in the cytosol, and are trafficked to the mitochondria, wherein they trigger pro-apoptotic events leading to shrinkage of basal KCs uniquely expressing FcRn in epidermis. During recovery, KCs extend their cytoplasmic aprons toward neighboring cells, but anti-Dsg antibodies prevent assembly of nascent desmosomes due to steric hindrance, thus rendering acantholysis irreversible. In conclusion, FcRn is a common acceptor protein for internalization of AMA and, perhaps, for PV autoantibodies to other intracellular antigens, and PV is a novel disease paradigm for investigating and elucidating the role of FcRn in this autoimmune disease and possibly other autoimmune diseases.

Diagnosis and clinical features of pemphigus foliaceus

Pemphigus foliaceus is an acquired autoimmune blistering disease in which the body's immune system produces IgG autoantibodies that target the intercellular adhesion glycoprotein desmoglein-1, which is principally expressed in the granular layer of the epidermis, resulting in the loss of intercellular connections between keratinocytes (acantholysis) and the formation of subcorneal blisters within the epidermis. This article summarizes the epidemiology, clinical features, techniques for diagnosis, and drugs associated with treatment of this rare disease.

Direct immunofluorescence in Behçet's disease: a controlled study with 108 cases

PURPOSE

Behçet's disease (BD) is a disease of unknown etiology, which has multisystemic involvement. This multisystemic involvement might be the clue for an autoimmune pathogenesis. In order to evaluate an autoimmune pathogenesis, we examined immunoreactans depositions in the skin of BD patients.

MATERIALS AND METHODS

The skin samples of 108 BD patients (28 perilesional skin, 44 positive pathergy test site, 22 negative pathergy test site, 14 normal skin) were examined for the depositions of immunoglobulin (Ig)M, IgG, IgA, complement 3 (C(3)), and fibrinogen (F) using direct immunofluorescence (DIF). The data were statistically compared to the DIF of 36 systemic lupus erythematosus (SLE) patients and 20 healthy controls using chi(2) Fisher exact test.

RESULTS

Highly significant immunoreactans depositions were obtained in BD (deposition rates: IgM 70.3%, IgG 0%, IgA 20.3%, C(3) 62.9%, F 83.3%). The comparison with SLE revealed no differences in IgM, IgA, and C(3). However, IgG deposition was higher in SLE while F deposition was higher in BD. In both BD and SLE, the Ig depositions were highly significant when the data were compared with the healthy controls.

CONCLUSION

The significant deposition of immunoreactans in BD, especially in the negative pathergy and the normal skin sites, were observed. This study is the first controlled study revealing positive Ig depositions in BD, and it is expected to help us to reconsider the autoimmune pathogenesis in BD.

Pemphigus in the XXI Century: New life to an old story

In this new century of pemphigus research, the search for novel treatments is switching from a monospecific approach, focused on immunosuppression, to a polyspecific approach that includes drugs acting on novel pathophysiologic pathways. Current research argues that acantholysis in pemphigus occurs as an active process resulting from intracellular signaling triggered as a result of IgG binding to the keratinocyte membrane antigens in a receptor-ligand fashion. Recent progress regarding the pathophysiology of pemphigus acantholysis led to, or was accompanied by, breakthrough discoveries of safer treatments. Both the identification of cell-surface receptors to acetylcholine among the nondesmoglein (Dsg) targets for pemphigus antibodies, and the elucidation of the cholinergic control of keratinocyte cell adhesion provide an explanation for the therapeutic efficacy of cholinomimetics in patients with pemphigus. In patients' skin, Fas-L, TNFalpha, and, probably, IL-1alpha act as autocrine/paracrine co-factors for anti-keratinocyte IgG. Thus, it appears that an array of interconnected signaling cascades is responsible for acantholysis and cell death in pemphigus. Future studies should define the signaling pathways mediating acantholysis that occur in individual pemphigus patients and identify the membrane proteins (receptors) triggering signaling along a specific pathway upon their ligation by autoantibodies. It will be important to determine which pathway 1) leads directly to a loss of cell-cell adhesion (primary pathway), 2) which is being activated due to cell shrinkage/detachment (secondary pathway), 3) which contributes to utilization of altered proteins and organelles (scavenging pathway), and 4) which represents the cell defense (protective pathway). To dissect out the signaling pathways originating from binding of pemphigus IgG to non-Dsg targets on the keratinocyte plasma membrane experiments should be performed in cultures of murine keratinocytes grown from the Dsg3-/- mice or human keratinocytes with the knocked-down expression of the Dsg1 and/or Dsg3 gene by the RNA interference.

Guidelines

These guidelines for management of pemphigus vulgaris have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation.

Circulating pemphigus IgG in families of patients with pemphigus: comparison of indirect immunofluorescence, direct immunofluorescence, and immunoblotting

BACKGROUND

Patients with pemphigus vulgaris (PV) are genetically linked to two alleles of the HLA subgroup, and circulating antibodies were found in first-degree relatives of these patients, thus showing genetic predisposition.

OBJECTIVE

Our purpose was to determine the occurrence of circulating true PV-IgG in patients' relatives.

METHODS

Circulating PV-IgG was determined in 21 first-degree relatives of 12 patients with PV by indirect immunofluorescence on monkey esophagus, carcinoma A431 cultures, and Western immunoblotting. Direct immunofluorescence was performed on skin biopsy specimens of 20 relatives.

RESULTS

Circulating PV-IgG was detected in 15 relatives (71%) by all methods tested. Good correlation was found between immunoblot reactivity and immunofluorescence. Of the 15 "positive" relatives, only five showed fixation of IgG to epidermal cells in vivo.

CONCLUSION

The permeability of the epidermis or epidermal cell reactivity in vivo probably controls the expression of disease in patients' relatives.

Immunofluorescence study of pemphigus from north India

Both serum studies by indirect immunofluorescence (IIF) tests and skin biopsy examination by direct immunofluorescence (DIF) were performed on 22 cases of pemphigus with clinically active lesions. Twenty cases had pemphigus vulgaris and two, pemphigus foliaceus. The majority of cases (70%) were between 21 and 60 years old; the mean age was 39.5 +/- 12.7 years. There was no sex predilection. DIF showed the positive fluorescence of intercellular cement substance (ICS) of the epidermis in all 22 cases (100%). IgG was positive in 77.2%, followed sequentially by C3C (50%), IgA (45.45%), and IgM (36.36%). Six cases (27.27%) also showed granular immunoglobulin and/or complement deposits at the dermoepidermal junction. IIF detected serum antiepithelial antibodies in 18 cases (81.81%) using human esophagus as substrate. Most of these cases (88.88%) showed IgG type of antibodies; the other 11.11% exhibited IgA and IgM in low concentrations. 1+ titer positivity was observed in 15 cases. This study demonstrates the value of DIF for a definitive diagnosis of pemphigus. However, it is also important to appreciate that immunofluorescence is not a substitute for histopathology, but rather complementary to it.

Management of the immunobullous disorders. II. Pemphigus

In the second of our reviews on the management of the immunobullous disorders, we review the therapy of pemphigus disorders, including pemphigus vulgaris, pemphigus vegetans, pemphigus foliaceus, pemphigus erythematosus, pemphigus herpetiformis, drug-induced pemphigus, IgA pemphigus and paraneoplastic pemphigus.

Treatment of oral pemphigus vulgaris

BACKGROUND

Oral pemphigus is considered to represent either an initial stage of pemphigus vulgaris that should be treated with high doses of immunosuppressive drugs to prevent its spread to the skin or a variety of the disease that does not need aggressive treatment. The absence of a widely accepted therapeutic method and the obscure nature of this disease prompted this study.

METHODS

Twenty-eight patients with oral pemphigus were randomly divided into three groups. The first group received only steroids at a dose of 40 mg of prednisone equivalent. In the other two groups the same dose of steroids was administered, but combined with either 100 mg of cyclophosphamide or 5 mg/kg of cyclosporine as an adjuvant. Direct immunofluorescence studies were performed on specimens obtained from both buccal mucosa and oral skin.

RESULTS

There was no significant difference in the duration of treatment required to achieve remission and in the relapse rate among the three groups. The incidence of complications was higher with combination treatment. Deposited immunoreactants were detected with equal frequency in specimens obtained from the buccal mucosa and normal skin.

CONCLUSIONS

Oral pemphigus most likely represents an initial stage of a disease that can become generalized. Administration of moderate doses of steroids alone is effective in controlling the disease.

Pemphigus in remission: value of negative direct immunofluorescence in management

BACKGROUND

Pemphigus vulgaris is characterized by relapses and remission, and there are currently no sensitive markers to predict remission.

OBJECTIVE

Our purpose was to determine if direct immunofluorescence (DIF) performed during clinical remission of pemphigus is useful in management of the disease.

METHODS

Twenty-eight patients with pemphigus that was in clinical remission (i.e., patients who were taking low-dose prednisolone [10 mg/day] and had been blister-free for at least 6 months) underwent DIF. Therapy was then discontinued and patients were prospectively followed up for 5 years.

RESULTS

Twenty-two patients had negative results and six patients had positive results of DIF. The disease remained in remission in three quarters of the patients with negative results of DIF. Of those who had a relapse, intercellular C3 on DIF and oral lesions on initial presentation were important risk factors, and the relapses in patients with negative results of DIF were mild. The biopsy site was unimportant. All patients with positive results of DIF had major relapses within 3 months of cessation of therapy.

CONCLUSION

DIF should be performed before therapy is discontinued. A negative DIF finding is a good indicator of remission in pemphigus.

Variation in the deposition of the antibodies at different anatomical sites in linear IgA disease of adults and chronic bullous disease of childhood

The diagnosis of linear IgA disease of adults (LAD) and chronic bullous disease of childhood (CBDC) relies upon finding a linear band of IgA at the basement membrane zone on direct immunofluorescence. This study examines the regional variation in antigen expression in the skin of affected individuals. Direct immunofluorescence was performed on biopsies from four different sites in 17 patients with these diseases. In two patients a biopsy from the volar surface of the forearm was negative, but other sites were positive; in the remaining patients there was no variation in antibody expression with site. It is therefore recommended that, if a single diagnostic biopsy is to be taken, the volar surface of the forearm is avoided.

Development of concepts of etiology, pathogenesis and treatment of pemphigus vulgaris based on the hypothesis of atavistic origin of the disease

Atavistically dependent expression of pemphigus vulgaris 'immune' antigen (PVIA) on the human epidermocyte surface is hypothetically the key factor of autoimmune aggression onset in pemphigus patients. Normal epidermocytes can express PVIA in response to a putative factor of 'sheding' as well as to certain biologic, chemical and physical effects. Taking into account the fact that the antibodies against 'shedding' factor carry out the function of anti-idiotypic ones, they can be used as blocking antibodies in treatment of pemphigus vulgaris.

Ultrastructural study of clinically uninvolved skin of patients with pemphigus vulgaris

We investigated skin biopsies from pemphigus vulgaris (PV) patients by light, fluorescent and electron microscopy in order to study the ultrastructural appearances of epidermis at the pre-acantholytic stage. The biopsies were obtained from uninvolved forearm skin in 10 patients with PV in the acute stage of the disease, from perilesional skin of the same patients as well as from the forearm skin of 10 healthy subjects. Light microscopy showed no pathological changes in clinically uninvolved skin of pemphigus patients. Direct immunofluorescence confirmed the presence of IgG auto-antibodies fixed in intercellular space of the spinous-cell layer of uninvolved skin. Electron microscopy of the uninvolved skin biopsies revealed the following changes: disintegration of desmosomes of spinous cells with their replacement by finger-shaped protrusions of cytoplasm; clarification of the nuclear matrix; widening of the perinuclear slit; an increased number of secondary lysosomes in cells; oedema and swelling of mitochondria with destruction of their cristae. The cells retained their polygonal shape and the intercellular distance did not increase. We conclude that at the pre-acantholytic stage the breakage and dissolution of desmosomes precedes the increase in the intercellular space.

The usefulness of immunofluorescent tests in pemphigus patients in clinical remission

Direct and indirect immunofluorescent studies (DIF, IIF) were performed on 24 pemphigus vulgaris patients who were in a state of clinical remission. The tests were repeated after an interval of 6 months. All the patients were on maintenance therapy with oral prednisone. The DIF in eight patients showed negative results among whom seven remained negative. Six patients out of 24 showed weakly positive fluorescence and ten patients showed strong positive fluorescence. The IIF was negative in 17 patients and positive in seven patients who also showed positive DIF. During a follow-up period of 20 months, one of eight patients with negative DIF relapsed compared with two of six patients with weak positive DIF and five of 10 patients with strong DIF. Five patients with strong DIF for IgG also had C3, of whom three relapsed, compared with five of 19 patients who were negative for C3. Four of seven patients with positive IIF relapsed compared with four of 17 with negative IIF. It is suggested that repeated DIF tests in pemphigus patients, who are in clinical remission, may serve as an indicator for the immunological activity and be of help in the management of these cases.

Complement activation in Brazilian pemphigus foliaceus

Brazilian pemphigus foliaceus is an autoimmune blistering skin disease of man that has a very high incidence in a confined geographical distribution. Rocket immunoelectrophoresis of plasma showed increased levels of complement fragments, C4d and Ba, indicating activation of complement through both the classical and the alternative pathways. Less sensitive methods such as CH50, total C3 and C4 did not demonstrate this activation, and immune complex measurements were within normal range. While complement may not be absolutely necessary for the development of skin lesions, our longitudinal studies show that activation of complement is at its highest during the most active phase of the disease.

Autoreactive cytotoxic T lymphocytes in pemphigus and pemphigoid

In order to know whether effector cells are capable of recognizing the epidermal targets in pemphigus vulgaris (PV) and bullous pemphigoid (BP), non-adherent cells (NAC) of peripheral blood from 27 primary PV, 19 BP patients and 12 healthy volunteers were used in cytotoxic tests. Autologous, allogenic and murine epidermal keratinocytes as well as autologous and allogenic fibroblasts were employed as targets. Total esterase activity of serine proteinases was measured in supernatants of samples and the results obtained were compared with the data received in 51Cr-release assay. These two techniques yielded similar results. The effector cells of PV and BP patients were found to lyse the epidermal target cells without presensitization in vitro. Epidermal cells from involved and uninvolved skin of PV patients, as well as from perilesional skin of BP patients, were highly sensitive to cytotoxic effect on the part of effector cells. The NAC activity in BP was higher than in PV. On the one hand, the obtained data suggest that PV and BP patients develop autoreactive cytotoxic T lymphocytes, sensitized to pemphigus and pemphigoid antigens, respectively, and on the other hand that epidermocytes in pemphigus and pemphigoid patients turned to be more fragile compared to normal human epidermal keratinocytes. It was supposed that cell-mediated cytotoxic reactions are probably related to enhanced proteolytic activity in the site of bullous eruption.