Frequency and Correlation of Peripheral and Tissue Eosinophilia with Clinical Manifestations in Patients with Bullous Pemphigoid

INTRODUCTION

Bullous pemphigoid (BP) is an autoimmune disease involving the sub-epidermal layer. Eosinophilia may play a role in the pathogenesis of BP.

OBJECTIVES

We aimed to investigate the correlation between dermal or peripheral eosinophilia with clinical presentations in patients with BP.

METHODS

This cross-sectional study was conducted on 108 BP patients from January 2010 to September 2019. Clinical data were recovered. Skin biopsies were re-evaluated, and the Bullous Pemphigoid Disease Area Index (BPDAI) severity score was calculated. Finally, the relationship between clinical features of BP and dermal or peripheral eosinophilia was analyzed.

RESULTS

A total number of 108 patients were included in this study. Thirty-five were excluded due to our exclusion criteria. Finally, data from 73 patients were analyzed. Fifty-seven point five percent of the population was female. There was a significant direct correlation (r = 0.33) between BPDAI severity score and tissue eosinophilia (P = 0.03). No significant relationship was found between BPDAI severity score and peripheral eosinophilia (P = 0.52). There were significant positive correlations between tissue eosinophilia with absolute serum eosinophil count (P = 0.002; r = 0.49) and percentage (P < 0.0001; r = 0.89).

CONCLUSIONS

This study revealed significant relationships between tissue eosinophilia and BP severity. These findings could be useful in clinical practice. The possible role of eosinophils in BP clinical features should be considered as a promising help for better diagnosis and treatment.

Anti-α6β4 integrin autoantibodies inhibit the binding of laminins to α6β4 integrin in patients with pemphigoid and affect the gastrointestinal tract

BACKGROUND

Anti-α6β4 integrin autoantibodies can be observed in some patients with mucous membrane pemphigoid. We have previously identified anti-α6β4 integrin extracellular domain autoantibodies together with anti-BP180 NC16A antibodies in a patient with DPP-4 inhibitor-induced bullous pemphigoid. However, the significance and impact of anti-α6β4 integrin antibodies are unknown.

OBJECTIVES

To characterize anti-α6β4 integrin extracellular domain autoantibodies in pemphigoid patients, to determine whether these antibodies inhibit laminin-α6β4 integrin binding and to observe their systemic effects.

METHODS

Anti-α6β4 integrin autoantibodies were analysed by staining cells expressing the extracellular region of α6β4 integrin with sera from 20 patients with pemphigoid. The anti-α6β4 integrin autoantibodies were characterized using different transfectants. The binding of laminins to α6β4 integrin was studied using cells expressing the activated conformation of α6β4 integrin and the inhibitory effect of the autoantibodies on the binding of laminins to α6β4 integrin was tested. Trends in antibody titres and clinical symptoms were quantified and analysed.

RESULTS

IgG autoantibodies against the extracellular domain of anti-α6β4 integrin were found in some patients with pemphigoid. Laminin binding to α6β4 integrin was observed in the active conformation of α6β4 integrin, and serum from a patient with a high titre of anti-α6β4 integrin antibodies inhibited the binding of both laminin-511 and laminin-332 to α6β4 integrin. α6β4 integrin is expressed on the basement membrane of both skin and small intestine, and exfoliation was observed in the patient's epidermis and small intestinal epithelium. A reduction in the titre of the anti-α6β4 integrin antibody was associated with improvement in both skin and gastrointestinal symptoms.

CONCLUSIONS

This study demonstrated the presence of anti-α6β4 integrin extracellular domain-specific autoantibodies in some patients with pemphigoid. In addition, these autoantibodies showed inhibitory activity on α6β4 integrin-laminin binding. Anti-α6β4 integrin antibodies can affect the gastrointestinal tract as well as the skin and oral mucosa.

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.

Bullous pemphigoid diagnosis: the role of routine formalin-fixed paraffin-embedded skin tissue immunochemistry

The gold standard for diagnosing bullous pemphigoid (BP) is the detection of linear deposition of IgG and/or C3 at the dermoepidermal junction using direct immunofluorescence (DIF). Because DIF has several disadvantages, primarily the requirement for frozen specimens, we assessed the diagnostic value of immunohistochemical (IHC) staining for BP detection. Eighty-eight patients with bullous lesions were included in this study. IHC staining for C3d, C4d, and IgG was performed on 88 samples, which included specimens from patients with DIF-confirmed BP (n = 43), clinicopathologically suspected BP with negative DIF results (n = 9), and other bullous diseases (n = 36). Diagnosis based on positive results for C3d, C4d, or IgG in IHC staining detected 86% of DIF-confirmed BP cases. The sensitivity of IHC staining for the detection of DIF-confirmed BP cases and clinicopathologically suspected BP cases was similar to that of DIF (80.8% vs. 84.3%), but the specificity was higher (83.3% vs. 75.0%). Five of the nine clinicopathologically suspected BP cases were diagnosed using IHC staining. Thus, IHC staining of routine biopsy material could be an alternative method for diagnosing BP. IHC staining has considerable diagnostic potential, especially in cases with a high suspicion of BP, but negative or suboptimal DIF results.Please check and confirm the author names and initials are correct. Author 2: Given name: [Chul Hwan] Family name: [Kim], Author 3: Given name: [Yoo Jin] Family name: [Lee].Checked it.

Prominent Role of Type 2 Immunity in Skin Diseases-Beyond Atopic Dermatitis

Type 2 immunity, illustrated by T helper 2 lymphocytes (Th2) and downstream cytokines (IL-4, IL-13, IL-31) as well as group 2 innate lymphoid cells (ILC2), is important in host defense and wound healing.¹ The hallmark of type 2 inflammation is eosinophilia and/or high IgE counts and is best recognized in atopic diathesis. Persistent eosinophilia, such as seen in hypereosinophilic syndromes, leads to fibrosis and hence therapeutic Type 2 inhibition in fibrotic diseases is of high interest. Furthermore, as demonstrated in cutaneous T cell lymphoma, advanced disease is characterized by Th1 to Th2 switch allowing cancer progression and immunosuppression. Development of targeted monoclonal antibodies against IL-4Rα (eg, dupilumab) led to a paradigm shift for the treatment of atopic dermatitis (AD) and stimulated research to better understand the role of Type 2 inflammation in other skin conditions. In this review, we summarize up to date knowledge on the role of Type 2 inflammation in skin diseases other than AD and highlight whether the use of Type 2 targeted therapies has been documented or is being investigated in clinical trials. This manuscript reviews the role of Type 2 inflammation in dermatitis, neurodermatitis, IgE-mediated dermatoses (eg, bullous pemphigoid, chronic spontaneous urticaria), sclerodermoid conditions and skin neoplasms.

Bullous pemphigoid-like rash revealing hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is a rare haematologic disorder characterised by unexplained, persistent eosinophilia with organ involvement. We report the case of a 74-year-old patient who presented with a pemphigoid-like bullous rash as the only manifestation of an HES. This report highlights the importance of the dermatological manifestations of this potentially life-threating condition that may initially present as a skin-limited disease. Bullous pemphigoid (BP) is a very common autoimmune blistering dermatosis that may share common clinical and histological features or associate with an HES. HES should be considered when patients diagnosed with BP demonstrate atypical course under corticosteroids and/or recalcitrant blood eosinophilia.

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.

False-Negative Rate of Direct Immunofluorescence on Lower Extremities in Bullous Pemphigoid

ABSTRACT

Bullous pemphigoid (BP) is the most common autoimmune blistering disorder of the skin. It is typified by tense blisters with a subepidermal split and mixed dermal inflammatory infiltrate on histology. Biopsy of the perilesional skin for direct immunofluorescence (DIF) has become the gold standard in the diagnosis of BP. Currently there is a pervasive clinical opinion that the lower extremity is a site with a high false-negative rate (FNR) for DIF in the diagnosis of BP. This notion is primarily based on 2 early studies from the 1980s without more recent confirmatory studies. To readdress this question regarding the lower extremities, a retrospective study from 2012 to 2018 was performed in our institution that evaluated the FNR of DIF by an anatomical site in the diagnosis of BP. Cases of BP were identified using standard criteria (clinical and histological data reviewed in cases with negative DIF), and overall, 79 patients were included in the study. A total of 4 false-negative DIF biopsies were verified. Two negative DIF were from the lower extremity yielding a FNR of 10% compared with 4% on the trunk and 3% from the upper extremity, with no statistically significant difference by anatomical sites. Our study fails to demonstrate a high FNR of DIF from the lower extremity in the diagnosis of BP.

Association Between Bullous Pemphigoid and Dipeptidyl Peptidase 4 Inhibitors: A Retrospective Cohort Study

BACKGROUND

The association between dipeptidyl peptidase 4 inhibitors (DPP-4i) and bullous pemphigoid (BP) has been demonstrated in several studies. The main aim of this study was to estimate the use of DPP-4i treatment in patients diagnosed with BP in our setting.

METHODS

We selected patients histologically diagnosed with BP in our department between October 2015 and October 2018 and performed a retrospective chart review to assess clinical and epidemiological data and direct immunofluorescence (DIF) patterns.

RESULTS

Of the 70 patients diagnosed with BP during the study period, 50% were diabetic and 88.57% of these were being treated with a DPP-4i when diagnosed with BP. The most common DPP-4i was linagliptin (used in 18.6% of patients), followed by vildagliptin (17.1%). The median latency period between initiation of DPP-4i treatment and diagnosis of BP was 27.5 months for all treatments, 16 months for linagliptin, and 39 months for vildagliptin (log rank < 0.01). A negative DIF result was significantly more common in patients not being treated with a DPP-4i. The DIF pattern most strongly (and significantly) associated with DPP-4i treatment was linear immunoglobulin G deposits along the dermal-epidermal junction. DPP-4i treatment was withdrawn in 87% of patients and 96% of these achieved a complete response.

CONCLUSIONS

DPP-4i treatment is very common in patients with BP in our setting. The latency period between start of treatment and onset of BP seems to be shorter with linagliptin than with other types of gliptins. Patients receiving DPP-4i treatment may show different DIF patterns to those not receiving treatment.

Advances in the diagnosis of autoimmune bullous dermatoses

Autoimmune bullous dermatoses are defined by autoantibodies directed against adhesion proteins in the epidermis or basement membrane zone, resulting in blister formation on the skin and mucosa. Diagnosis depends on lesional biopsy for histopathology and perilesional biopsy for direct immunofluorescence. Additional diagnostic methods include indirect immunofluorescence, enzyme-linked immunosorbent assay, and immunoblot (Western blot), which may be selected in specific clinical scenarios due to improved sensitivity and/or specificity. This contribution reviews the available evidence supporting the use of each method to provide a practical reference for clinicians when diagnosing autoimmune bullous disorders. Techniques and cost are reviewed, and newer diagnostic techniques with potential for clinical application are.