Enhanced diagnostic immunofluorescence using biopsies transported in saline

The Role of Serology in the Diagnosis of Ocular Predominant Mucous Membrane Pemphigoid and the Search for an Ocular-Specific Autoantigen

Ocular predominant mucous membrane pemphigoid (oMMP) is a severe subtype of MMP that can lead to scarring and blindness. While conjunctival biopsy for direct immunofluorescence (DIF) is considered the gold standard for diagnosis, limited sensitivity results in a false-negative rate upwards of 40%. Likewise, it remains unclear to what extent a negative biopsy, whether false-negative or true-negative, results in a different prognosis, with patients previously termed "pseudopemphigoid" demonstrating comparable disease progression. Serologic testing allows for a less invasive means to demonstrate circulating autoantibodies against known autoantigens in pemphigoid diseases. Patients with MMP, particularly oMMP, however, typically demonstrate low titers of circulating autoantibodies, limiting the diagnostic utility of these tests. The autoantigen integrin β4 has been previously reported to be a specific marker of pure ocular MMP, while in the majority of patients with oMMP, the identified target antigens are BP180 (type XVII collagen) and laminin 332. Recent studies have, however, demonstrated inconsistent reactivity and specificity for integrin β4 as an ocular-specific marker in MMP. Herein, we review the role of serologic testing in the diagnosis and prognosis of oMMP, as well as the current understanding of autoantigens in oMMP.Abbreviations: BMZ - basement membrane zone, DIF - direct immunofluorescence, IIF - indirect immunofluorescence, MMP - mucous membrane pemphigoid, oMMP - ocular predominant mucous membrane pemphigoid.

Direct immunofluorescence demystified: Essential insights and recent advances for dermatologists

Direct immunofluorescence (DIF) is widely used in dermatopathology for the diagnosis of autoimmune blistering diseases (AIBDs), cutaneous vasculitis, and connective tissue disorders. Although it is easy and useful to perform, it needs technical expertise and experience for proper interpretation. The yield of DIF depends on multiple factors including the adequacy, transportation, storage, processing, and interpretation of the biopsy specimen. Effective collaboration between the dermatologist and dermatopathologist along with meticulous clinico-pathological correlation is crucial for accurately interpreting DIF in the appropriate clinical context. In this narrative review of DIF in dermatology, we discuss the indications of DIF, recent updates on the selection of optimum biopsy sites, basic techniques of DIF including the classical transport medium and its alternatives, processing and staining technique, patterns in various diseases, advancements such as serration pattern analysis, and latest recommendations on the use of DIF in cutaneous disorders.

Direct Immunofluorescence of Skin and Oral Mucosa: Guidelines for Selecting the Optimum Biopsy Site

Direct immunofluorescence is a vital diagnostic test for assessing vesiculobullous disorders, vasculitides, and connective tissue diseases. It is a robust and valuable technique that offers essential diagnostic information for many critical dermatoses. Dermatopathologists depend heavily on the data obtained from direct immunofluorescence evaluation to confirm final diagnoses. Selecting the most appropriate biopsy site is necessary for maximizing diagnostic accuracy, and the best site may vary depending on the clinical differential diagnosis. Inaccurate biopsy site selection can significantly impact the accuracy of the results. To optimize the use of direct immunofluorescence studies, this review provides helpful guidelines and some practical tips for selecting the best biopsy site.

Chemically programmable bacterial probes for the recognition of cell surface proteins

Common methods to label cell surface proteins (CSPs) involve the use of fluorescently modified antibodies (Abs) or small-molecule-based ligands. However, optimizing the labeling efficiency of such systems, for example, by modifying them with additional fluorophores or recognition elements, is challenging. Herein we show that effective labeling of CSPs overexpressed in cancer cells and tissues can be obtained with fluorescent probes based on chemically modified bacteria. The bacterial probes (B-probes) are generated by non-covalently linking a bacterial membrane protein to DNA duplexes appended with fluorophores and small-molecule binders of CSPs overexpressed in cancer cells. We show that B-probes are exceptionally simple to prepare and modify because they are generated from self-assembled and easily synthesized components, such as self-replicating bacterial scaffolds and DNA constructs that can be readily appended, at well-defined positions, with various types of dyes and CSP binders. This structural programmability enabled us to create B-probes that can label different types of cancer cells with distinct colors, as well as generate very bright B-probes in which the multiple dyes are spatially separated along the DNA scaffold to avoid self-quenching. This enhancement in the emission signal enabled us to label the cancer cells with greater sensitivity and follow the internalization of the B-probes into these cells. The potential to apply the design principles underlying B-probes in therapy or inhibitor screening is also discussed here.

What the rheumatologist needs to know about skin biopsy

The skin biopsy plays an important and powerful role in helping diagnose rheumatic diseases that present with cutaneous findings. As the skin is a very accessible organ, and the skin biopsy can be performed quickly as an in-office procedure, the skin biopsy is utilized frequently in patients with rheumatic diseases. However, the more challenging aspects of performing the biopsy, such as identifying the type of biopsy to perform, the site (s) to biopsy, the type of media to use, and the interpretation of histopathologic data are nuanced and require considerable thought. In this review, we discuss the common skin findings in rheumatic diseases and the general indications for skin biopsies in these diseases. We then summarize how to perform various skin biopsy techniques and how to select the biopsy technique. Finally, we discuss important rheumatic disease-specific considerations for skin biopsy, including where to biopsy and how to interpret the pathologic reports.

European Guidelines (S3) on diagnosis and management of mucous membrane pemphigoid, initiated by the European Academy of Dermatology and Venereology - Part II

This guideline has been initiated by the task force Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology, including physicians from all relevant disciplines and patient organizations. It is a S3 consensus-based guideline that systematically reviewed the literature on mucous membrane pemphigoid (MMP) in the MEDLINE and EMBASE databases until June 2019, with no limitations on language. While the first part of this guideline addressed methodology, as well as epidemiology, terminology, aetiology, clinical presentation and outcome measures in MMP, the second part presents the diagnostics and management of MMP. MMP should be suspected in cases with predominant mucosal lesions. Direct immunofluorescence microscopy to detect tissue-bound IgG, IgA and/or complement C3, combined with serological testing for circulating autoantibodies are recommended. In most patients, serum autoantibodies are present only in low levels and in variable proportions, depending on the clinical sites involved. Circulating autoantibodies are determined by indirect IF assays using tissue substrates, or ELISA using different recombinant forms of the target antigens or immunoblotting using different substrates. The major target antigen in MMP is type XVII collagen (BP180), although in 10-25% of patients laminin 332 is recognized. In 25-30% of MMP patients with anti-laminin 332 reactivity, malignancies have been associated. As first-line treatment of mild/moderate MMP, dapsone, methotrexate or tetracyclines and/or topical corticosteroids are recommended. For severe MMP, dapsone and oral or intravenous cyclophosphamide and/or oral corticosteroids are recommended as first-line regimens. Additional recommendations are given, tailored to treatment of single-site MMP such as oral, ocular, laryngeal, oesophageal and genital MMP, as well as the diagnosis of ocular MMP. Treatment recommendations are limited by the complete lack of high-quality randomized controlled trials.

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.

Practical Direct Immunofluorescence

Direct immunofluorescence (DIF) remains a valuable tool that may be underused because of perceived challenges in the interpretation, limitations, and processing of DIF specimens. The aim of this review is to provide a practical guide for appropriately incorporating DIF in a variety of clinical diseases, such as autoimmune blistering disorders. In vasculitis, the role of DIF continues to evolve, particularly in the setting of IgA vasculitis. Although typically not indicated for the workup of connective tissue disease, DIF may be helpful in cases with negative serologies, nondiagnostic histologic findings, or scarring alopecia. Practical pearls for biopsy technique, specimen handling, and storage are also discussed.

Oral Lesions in Autoimmune Bullous Diseases: An Overview of Clinical Characteristics and Diagnostic Algorithm

Autoimmune bullous diseases are a group of chronic inflammatory disorders caused by autoantibodies targeted against structural proteins of the desmosomal and hemidesmosomal plaques in the skin and mucosa, leading to intra-epithelial or subepithelial blistering. The oral mucosa is frequently affected in these diseases, in particular, in mucous membrane pemphigoid, pemphigus vulgaris, and paraneoplastic pemphigus. The clinical symptoms are heterogeneous and may present with erythema, blisters, erosions, and ulcers localized anywhere on the oral mucosa, and lead to severe complaints for the patients including pain, dysphagia, and foetor. Therefore, a quick and proper diagnosis with adequate treatment is needed. Clinical presentations of autoimmune bullous diseases often overlap and diagnosis cannot be made based on clinical features alone. Immunodiagnostic tests are of great importance in differentiating between the different diseases. Direct immunofluorescence microscopy shows depositions of autoantibodies along the epithelial basement membrane zone in mucous membrane pemphigoid subtypes, or depositions on the epithelial cell surface in pemphigus variants. Additional immunoserological tests are useful to discriminate between the different subtypes of pemphigoid, and are essential to differentiate between pemphigus and paraneoplastic pemphigus. This review gives an overview of the clinical characteristics of oral lesions and the diagnostic procedures in autoimmune blistering diseases, and provides a diagnostic algorithm for daily practice.

Assessment of Diagnostic Strategy for Early Recognition of Bullous and Nonbullous Variants of Pemphigoid

Importance

A substantial number of patients with bullous pemphigoid do not develop skin blisters and may not have received the correct diagnosis. Diagnostic criteria and an optimal diagnostic strategy are needed for early recognition and trials.

Objectives

To assess the minimal requirements for diagnosis of bullous and nonbullous forms of pemphigoid and to evaluate the optimal diagnostic strategy.

Design, Setting, and Participants

This paired, multivariable, diagnostic accuracy study analyzed data from 1125 consecutive patients with suspected pemphigoid who were referred to the Groningen Center for Blistering Diseases from secondary and tertiary care hospitals throughout the Netherlands. Eligible participants were patients with paired data on at least (1) a skin biopsy specimen for the direct immunofluorescence (DIF) microscopy test; (2) indirect immunofluorescence on a human salt-split skin substrate (IIF SSS) test; and (3) 1 or more routine immunoserologic tests administered between January 1, 2002, and May 1, 2015. Samples were taken from patients at the time of first diagnosis, before introduction of immunosuppressive therapy, and within an inclusion window of a maximum of 4 weeks. Data analysis was conducted from October 1, 2015, to December 1, 2017.

Main Outcomes and Measures

Pairwise DIF, IIF SSS, IIF on monkey esophagus, BP180 and BP230 enzyme-linked immunosorbent assays, and immunoblot for BP180 and BP230 tests were performed. The results were reported in accordance with 2015 version of the Standards for Reporting Diagnostic Accuracy.

Results

Of the 1125 patients analyzed, 653 (58.0%) were women and 472 (42.0%) were men, with a mean (SD) age of 63.2 (19.9) years. In total, 343 participants received a pemphigoid diagnosis, with 782 controls. Of the 343 patients, 74 (21.6%, or 1 in 5) presented with nonbullous pemphigoid. The DIF microscopy was the most sensitive diagnostic test (88.3% [n = 303]; 95% CI, 84.5%-91.3%), whereas IIF SSS was less sensitive (77.0% [n = 263]; 95% CI, 72.2%-81.1%) but was highly specific (99.9%; 95% CI, 99.3%-100%) and complemented most cases with negative DIF findings. Results of the BP180 NC16A enzyme-linked immunosorbent assay did not add diagnostic value for initial diagnosis in multivariable logistic regression analysis of combined tests. These findings lead to the proposed minimal criteria for diagnosing pemphigoid: (1) pruritus and/or predominant cutaneous blisters, (2) linear IgG and/or C3c deposits (in an n-serrated pattern) by DIF on a skin biopsy specimen, and (3) positive epidermal side staining of IgG by IIF SSS on a serum sample; this proposal extends bullous pemphigoid with the unrecognized nonbullous form.

Conclusions and Relevance

Both DIF and IIF SSS tests should be performed for diagnosis of the bullous and nonbullous variants of pemphigoid, and the BP180 NC16A enzyme-linked immunosorbent assay is recommended as an add-on test for disease activity monitoring.

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.

A comparative study of Michel's medium versus honey as a transport medium for skin specimens prior to direct immunofluorescence microscopy and antigen mapping

BACKGROUND

Michel's medium (MM) is currently the recommended transport medium for skin biopsy specimens prior to direct immunofluorescence (DIF) microscopy.

OBJECTIVE

To compare the utility of honey with that of MM as a transport medium for skin biopsy specimens used for DIF and antigen mapping.

METHODS

Group I consisted of 45 freshly-taken skin specimens earmarked for DIF testing. It was divided into three groups (A, B and C), each containing 15 specimens. Biopsy specimens were sliced into two, one each for MM and honey. Samples in group A were processed at the end of week 1 while those in group B and C were processed at the end of weeks 2 and 4, respectively. Group II consisted of five specimens of epidermolysis bullosa (EB) which was further divided into three groups; two specimens were processed for antigen mapping at the end of week 1, while others were processed at the end of week 2 (two specimens) and 4 (one specimen).

RESULTS

Sensitivity of honey as a transport medium for skin biopsy specimens was 100%, 92.6% and 53.8% at weeks 1, 2 and 4, respectively. The antigen mapping was positive in all specimens.

CONCLUSION

Utility of honey was comparable to MM for DIF samples tested at weeks 1 and 2 but was lower at week 4.

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.

Epidermolysis Bullosa Acquisita: The 2019 Update

Epidermolysis bullosa acquisita (EBA) is an orphan autoimmune disease. Patients with EBA suffer from chronic inflammation as well as blistering and scarring of the skin and mucous membranes. Current treatment options rely on non-specific immunosuppression, which in many cases, does not lead to a remission of treatment. Hence, novel treatment options are urgently needed for the care of EBA patients. During the past decade, decisive clinical observations, and frequent use of pre-clinical model systems have tremendously increased our understanding of EBA pathogenesis. Herein, we review all of the aspects of EBA, starting with a detailed description of epidemiology, clinical presentation, diagnosis, and current treatment options. Of note, pattern analysis via direct immunofluorescence microscopy of a perilesional skin lesion and novel serological test systems have significantly facilitated diagnosis of the disease. Next, a state-of the art review of the current understanding of EBA pathogenesis, emerging treatments and future perspectives is provided. Based on pre-clinical model systems, cytokines and kinases are among the most promising therapeutic targets, whereas high doses of IgG (IVIG) and the anti-CD20 antibody rituximab are among the most promising "established" EBA therapeutics. We also aim to raise awareness of EBA, as well as initiate basic and clinical research in this field, to further improve the already improved but still unsatisfactory conditions for those diagnosed with this condition.

Serration pattern analysis for differentiating epidermolysis bullosa acquisita from other pemphigoid diseases

BACKGROUND

Direct immunofluorescence (DIF) microscopy of a skin biopsy specimen is the reference standard for the diagnosis of pemphigoid diseases (PDs). Serration pattern analysis enables the differentiation of epidermolysis bullosa acquisita (EBA) from other PDs using DIF microscopy alone. However, practice gaps need to be addressed in order to implement this technique in the routine diagnostic procedure.

OBJECTIVE

We sought to determine and optimize the technical requirements for serration pattern analysis of DIF microscopy and determine interrater conformity of serration pattern analysis.

METHODS

We compared serration pattern analysis of routine DIF microscopy from laboratories in Groningen, The Netherlands and Lübeck, Germany with 4 blinded observers. Skin biopsy specimens from 20 patients with EBA and other PDs were exchanged and analyzed. Various factors were evaluated, including section thickness, transport medium, and biopsy specimen processing.

RESULTS

The interrater conformity of our 4 observers was 95.7%. Recognition of serration patterns was comparable in samples transported in saline and in Michel's medium and with section thicknesses of 4, 6, and 8 μm.

LIMITATIONS

Limitations include our small sample size and the availability of 20 samples that were compared retrospectively.

CONCLUSION

DIF serration pattern analysis is not restricted by variation in laboratory procedures, transport medium, or experience of observers. This learnable technique can be implemented as a routine diagnostic method as an extension of DIF microscopy for subtyping PD.

Immunofluorescence of Autoimmune Bullous Diseases

Autoimmmune bullous diseases of skin and mucosa are uncommon, disabling, and potentially lethal diseases. For a quick and reliable diagnosis immunofluorescence is essential. This article describes two variants of immunofluorescence. The direct method uses a skin or mucosal biopsy of the patient to detect in vivo bound antibodies. Indirect immunofluorescence uses patient's serum and a substrate to visualize circulating autoantibodies. These two methods supplemented with advanced techniques allow reliable classification of autoimmune bullous diseases; not only the main entities pemphigus and pemphigoid, but also subclasses within these groups. This is important because prognosis and therapy vary among different variants of autoimmune bullous diseases.

Utility of immunofluorescence in dermatology

Immunofluorescence (IF) tests have redefined our understanding of many immune-mediated skin diseases, especially autoimmune blistering diseases (AIBDs). Nomenclature of certain AIBDs (for example, linear IgA diseases and IgA pemphigus) has been done based solely on the finding of tissue-bound immunoreactants as detected by IF tests. Direct and indirect are the two major types of IF tests; they are not only useful in the diagnosis but also guide the clinician in the treatment at least in certain AIBDs, as the titer of circulating antibodies as detected by IF reflects the disease activity. In this review, we describe techniques, various types of IF, and its modification.

Diagnostic value of immunohistochemistry on formalin-fixed, paraffin-embedded skin biopsy specimens for bullous pemphigoid

BACKGROUND

Direct immunofluorescence microscopy (DIF) studies constitute the gold standard for diagnosis of bullous pemphigoid (BP) but depend on the availability of specialized laboratories and often on an additional skin biopsy specimen.

OBJECTIVES

To assess the value of immunohistochemical analyses (IHCA) in the diagnosis of BP using formalin-fixed, paraffin-embedded skin biopsy specimens as an alternative to DIF; and to study the correlation between the results of IHCA and the presence of histological subepidermal blister formation and of circulating autoantibodies by indirect immunofluorescence studies using split skin or by enzyme-linked immunosorbent assays.

METHODS

We included all patients newly diagnosed with BP evaluated between 2008 and 2010. There were 51 consecutive skin biopsy specimens obtained from 38 patients with BP with positive DIF.

RESULTS

By IHCA, deposits of immunoreactants were found in 45% of all tested cases. Deposits of C3d, IgG, IgM, IgE and IgA were found in 37%, 23%, 2%, 0% and 0% of cases, respectively. Deposits of C3d and/or IgG were found in 79% of the 24 cases with a blister and in 83% of the 12 cases with subepidermal blistering and positive immunoserological analyses, respectively.

CONCLUSIONS

In contrast to previous studies, our findings in an unselected patient cohort indicate that IHCA are not sufficiently sensitive to replace DIF studies for confirming the diagnosis of BP. IHCA sensitivity significantly increases in the presence of histological blistering and/or of circulating autoantibodies. IHCA represents a potential rescue diagnostic technique only if specialized laboratories and/or a second biopsy specimen for DIF are unavailable.

Desmosomes in disease: a guide for clinicians

The large number of diseases occurring when desmosome constituents are impaired provides striking evidence for the key role of desmosomes in maintaining tissue integrity. A detailed understanding of the molecular alterations causing desmosomal dysfunction has, in turn, underpinned the development of novel diagnostic tools. This has salient clinical implications for dentists and oral medicine practitioners because the majority of desmosomal diseases affect the oral cavity. In the present article, we review the autoimmune, infectious, genetic, and neoplastic diseases that target the desmosome, with particular emphasis on clinical manifestations, diagnostic pathways, and relevant laboratory investigations.

Direct Immunofluorescence in Oral Lichen Planus

INTRODUCTION

Oral lichen planus (OLP) is a common immune-mediated oral mucosal disease. Diagnosis of OLP depends mainly on both clinical and histopathological features. Direct immunofluorescence (DIF) is a useful investigation method to distinguish between similar lesions and to confirm diagnosis in cases of uncharacterized features.

AIM

The purpose of this study was to evaluate the prevalence and pattern of DIF in a group of Thai patients with OLP.

MATERIALS AND METHODS

Records of clinically and histologically diagnosed OLP patients attending the Oral Medicine Clinic, Faculty of Dentistry, Mahidol University, Bangkok, Thailand were consecutively reviewed for DIF results. The DIF patterns in these patients were analysed.

RESULTS

There were 82 atrophic and/or erosive OLP patients with a mean age of 51.6 years. Male to female ratio was 1:5. Of these, 82.9% showed positive DIF. Buccal mucosa was superior to the gingiva and palate in terms of sensitivity for DIF. All specimens except one (98.5%) demonstrated deposition of fibrinogen at the basement membrane zone (BMZ) in a shaggy pattern. The most common DIF pattern was shaggy fibrinogen at BMZ with IgM deposition on the colloid bodies (CB) (35.3%) followed by shaggy fibrinogen along BMZ (27.9%).

CONCLUSION

The prevalence of positive DIF in Thai OLP patients was 82.9%. The most common finding was shaggy fibrinogen at BMZ. The typical pattern was shaggy fibrinogen along BMZ with or without positive IgM at CB. DIF pattern could be evaluated for the diagnosis of OLP lacking clinical and/or histopathological characteristic features.

Michel's Transport Medium as an Alternative to Liquid Nitrogen for PCR Analysis of Skin Biopsy Specimens

Formalin fixation and paraffin embedding are standard procedures for histopathological diagnosis and allow long-term archiving of tissue specimens. The cross-linking properties of formalin cause fragmentation of nucleic acids and reduce the sensitivity of PCR analysis. Michel's medium is a well-established transport medium used by dermatologists for biopsy transport to maintain tissue-fixed immunoreactants prior to direct immunofluorescence and immunoelectron microscopy. Here we report that Michel's medium also allows short-term preservation of DNA for PCR analysis and permits amplification of amplicons larger than 1 kb. Therefore, Michel's medium appears to be a reserve medium for performing PCR when no other samples are available.

Pre-bisection of a single skin biopsy does not produce technically inadequate specimens for direct immunofluorescence: a review of 3450 specimens

BACKGROUND

Evaluation of a potential immunobullous disorder typically requires two pieces of tissue obtained by skin biopsy: one placed in formalin for conventional microscopy and a second placed in a different transport medium suitable for direct immunofluorescence (DIF) testing. Clinical practice in this area is not standardized, with dermatologists either obtaining two biopsies or dividing (pre-bisecting) a single biopsy. Some DIF specimens are technically inadequate for interpretation of subepidermal imunobullous disorders because the basement membrane zone is not intact, but it is unknown whether pre-bisecting the tissue increases the risk of compromising the specimen.

OBJECTIVE

To investigate whether technically inadequate DIF specimens are associated with pre-bisection.

METHODS

DIF specimens were consecutively sampled from a single referral center and identified as whole (non-bisected) biopsy specimens or pre-bisected biopsy specimens. The proportion of inadequate specimens was calculated for both groups.

RESULTS

A total of 3450 specimens were included. The percentage of inadequate specimens was 5.072% (153/3016) for whole (non-bisected) specimens and 5.299% for pre-bisected specimens. This difference was not significant (chi square, p = 0.84). The study was sufficiently powered to detect a relative risk of 1.685.

CONCLUSIONS

Pre-bisection of a single skin biopsy does not significantly increase the risk of a technically inadequate specimen for direct immunofluorescence testing.

A Cross-sectional Study of Direct Immunofluorescence in the Diagnosis of Immunobullous Dermatoses

Background:

Autoimmune blistering diseases are a group of bullous disorders characterized by pathogenic antibodies directed at the target antigens, which are components of the desmosomes or adhesion complex at the dermoepidermal junction. Direct immunofluorescence (DIF) is invaluable in the diagnosis of these lesions.

Aim:

The aim of this study was to evaluate the sensitivity of DIF in immunobullous dermatoses and to study the pattern of DIF. The study also aims to correlate DIF with clinical and histologic findings and to analyze discrepancies.

Materials and Methods:

Total 100 biopsies received over a period of 2 years in the Department of Pathology were analyzed. DIF, histopathology and clinical data were reviewed.

Results:

Out of 100, 89 cases showed DIF patterns concordant with clinical/histologic diagnosis. The sensitivity of DIF was 94.44% (51/58) in the pemphigus and 84% (21/25) in the bullous pemphigoid (BP) group, 100% each in dermatitis herpetiformis (2/2) and linear IgA disease (1/1). A total of 11 histologically proven cases of immunobullous lesions were DIF negative-four (three of pemphigus vulgaris and one of BP) due to having no epidermis, three (cases of BP) owing to sampling/technical errors and the remaining four (cases of pemphigus vulgaris) due to being on treatment.

Conclusion:

Immunofluorescence helps confirm the diagnosis of bullous lesions in which there is clinical and the histopathologic overlap. Sampling errors contributed to false negative (FN) results.

Comparative study of direct and indirect immunofluorescence and of bullous pemphigoid 180 and 230 enzyme-linked immunosorbent assays for diagnosis of bullous pemphigoid

BACKGROUND

Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) are used for the laboratory diagnosis of bullous pemphigoid (BP).

OBJECTIVE

The diagnostic value of DIF and IIF on rabbit and monkey esophagus or human salt-split skin and commercial ELISAs was assessed.

METHODS

This was a single-center retrospective study where 313 patients with BP were compared with 488 control subjects.

RESULTS

DIF was the most sensitive test (90.8%) whereas sensitivities for IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 76.0%, 73.2%, 73.3%, 72.0%, and 59.0%, respectively. The sensitivity of the serologic tests was 88.8% altogether. The specificities for DIF, IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 98%, 96.5%, 97.1%, 100%, 94.1%, and 99.2%, respectively.

LIMITATIONS

The retrospective nature of study was a limitation. Correlation of diagnostic data with clinical manifestations or disease course was not possible.

CONCLUSIONS

In suspected BP, both serologic tests and DIF have to be performed because of a sensitivity issue. Although the ELISAs had a relatively low sensitivity, the serologic tests altogether almost reached the level of sensitivity of DIF. The specificities of all assays were excellent.

Evaluation and treatment of the newborn with epidermolysis bullosa

Epidermolysis bullosa (EB) is a heterogeneous group of inherited skin diseases characterized by increased skin fragility and variable degrees of extracutaneous involvement. The clinical spectrum ranges from localized skin disease to a life-threatening and disabling disease with extensive extracutaneous involvement. All four major types of EB, namely EB simplex, Junctional EB, Dystrophic EB and Kindler syndrome, can present with blistering and erosions at birth and cannot be distinguished clinically in the newborn period. The extensive differential diagnosis of blistering and erosions in the neonate must be considered and common etiologies ruled out. The diagnosis of EB can be confirmed via a skin biopsy for immunoflourescence mapping. This review discusses the four major subtypes of EB and their associated extracutaneous features. The evaluation of a newborn suspected of having EB, including diagnosis and management, is also reviewed.

Detection of linear IgE deposits in bullous pemphigoid and mucous membrane pemphigoid: a useful clue for diagnosis

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease of the skin associated with IgG autoantibodies to BP180 and BP230, while mucous membrane pemphigoid (MMP) comprises a heterogeneous group of autoimmune blistering diseases characterized by a predominant mucous membrane involvement and scarring tendency associated with an autoantibody response to various autoantigens, including BP180. While the pathogenicity of IgG autoantibodies to BP180 has been demonstrated in BP, the role of IgE autoantibodies in mediating tissue damage in BP and MMP is unclear.

OBJECTIVES

To assess the presence of tissue-bound IgE in patients with BP and MMP, and their correlation with distinct clinical features.

METHODS

In this retrospective study, we assessed the presence of IgE deposits as detected by direct immunofluorescence microscopy of skin biopsy specimens obtained from 44 and 13 patients with a new diagnosis of BP and MMP, respectively. Distinct clinical features at time of diagnosis, such as itch, urticarial papules and plaques and eczematous lesions, were noted.

RESULTS

In 18 of 44 (41%) patients with BP linear deposits of IgE of variable intensity were detectable along the dermoepidermal junction. In 14 (32%) of the cases, IgE deposits were found concomitantly with IgG and C3. In two (5%) patients, diagnosis of BP was based on the isolated detection of IgE together with consistent clinicopathological features. Nine of 13 (69%) patients with MMP also exhibited linear IgE deposits, including one case with isolated linear IgE deposits. Patients with BP with tissue-bound IgE deposits had clinically significant urticarial papules and plaques when compared with patients with BP without IgE deposits.

CONCLUSIONS

Our findings indicate that demonstration of tissue-bound IgE deposits provides an additional useful criterion for diagnosis of BP and MMP in some patients. Prospective studies are needed to better correlate the presence of tissue-bound and circulating IgE autoantibodies and their specificity with distinct clinical features and course of BP and MMP.

Diagnosis and clinical features of pemphigus vulgaris

Autoimmune bullous diseases are associated with autoimmunity against structural components that maintain cell-cell and cell-matrix adhesion in the skin and mucous membranes. They include those where the skin blisters at the basement membrane zone and those where the skin blisters within the epidermis (pemphigus vulgaris, pemphigus foliaceus, and other subtypes of pemphigus). The variants of pemphigus are determined according to the level of intraepidermal split formation. There are 5 main variants of pemphigus: pemphigus vulgaris, pemphigus foliaceus, pemphigus erythematosus, drug-induced pemphigus, and paraneoplastic pemphigus. This review focuses only on pemphigus vulgaris.

How to take skin biopsies for epidermolysis bullosa

The definitive diagnosis of inherited epidermolysis bullosa is best made with positive immunofluorescence antigenic mapping, transmission electron microscopy, and epidermolysis bullosa-related monoclonal antibody studies. However, immunofluorescence microscopy is faster and easier as compared with electron microscopy for subtyping epidermolysis bullosa. The severity of the disease varies with the structural protein involved. A proper diagnosis should be made as soon as possible, and skin biopsies help with diagnosis. This article describes the technique of skin biopsy.

Antiplectin autoantibodies in subepidermal blistering diseases

BACKGROUND

Hemidesmosomal proteins may become targets of autoimmunity in subepidermal blistering diseases. Well-known recognized autoantigens are the intracellular plaque protein BP230, the transmembrane BP180 and its shed ectodomain LAD-1.

OBJECTIVES

To establish the prevalence of autoimmunity against plectin, another intracellular plaque protein, and to investigate its antigenic sites.

METHODS

Two hundred and eighty-two patients with subepidermal blistering diseases, investigated by routine immunoblot analysis for possible antiplectin antibodies, were included in the study. Epitope mapping was performed using recombinantly produced overlapping plectin domains from the actin-binding domain to the rod domain. The COOH-terminal region of plectin was not included in the study.

RESULTS

In 11 of 282 (3.9%) patients an immunoblot staining pattern identical to that of antiplectin monoclonal antibody HD121 was found. Affinity-purified antibodies bound back to normal human skin in a pattern typical for plectin, i.e. to the epidermal basement membrane zone as well as to keratinocytes in the epidermis, and to myocytes. No binding was seen to plectin-deficient skin of a patient with epidermolysis bullosa simplex with muscular dystrophy. Epitope mapping of the plectin molecule showed that the central coiled-coil rod domain is an immunodominant hotspot as 92% of the sera with antiplectin antibodies reacted with it. Most patients with antiplectin antibodies also had antibodies to other pemphigoid antigens.

CONCLUSIONS

Plectin is a minor pemphigoid antigen with an immunodominant epitope located on the central rod domain.

[Mucous membrane pemphigoid with ocular involvement. Part I: Clinical manifestations, pathogenesis and diagnosis]

Mucous membrane pemphigoid is a subepidermal blistering autoimmune disorder characterized by predominant involvement of mucous membranes and the presence of autoantibodies against proteins of the dermal-epidermal junction. Lesions most frequently develop in the oral cavity followed, in descending order of frequency, by conjunctiva, nasopharynx, the anogenital region, skin, larynx, and oesophagus. When the lesions are restricted to the conjunctiva, the term ocular pemphigoid may be applied. Cicatrization of the plica is considered a pathognomonic sign in early disease. Recurrent conjunctival inflammation results in subepithelial fibrosis, which leads to fornix shortening, symblepharon formation and subsequent trichiasis and entropion. Even in the absence of conjunctival inflammation, ankyloblepharon may occur. In end stage disease, limbal stem cell deficiency, tear deficiency, and lid malpositions may occur and result in a total keratinization of the ocular surface. The diagnosis is based on clinical findings and the detection of linear deposits of IgG and/or IgA and/or C3 at the dermal-epidermal junction by direct immunofluorescence microscopy of a perilesional biopsy. Autoantibodies (against type XVII and VII collagen, laminin 5 and 6, alpha6beta4 integrin, BP230) have been detected in patient serum. In the case of ocular involvement, preferential reactivity against beta4 integrin has been described.