Eosinophil cationic protein levels parallel coagulation activation in the blister fluid of patients with bullous pemphigoid

Risk of Incident Venous Thromboembolism Among Patients With Bullous Pemphigoid or Pemphigus Vulgaris: A Nationwide Cohort Study With Meta-Analysis

Background Bullous pemphigoid (BP) and pemphigus vulgaris (PV) share similar pathophysiology with venous thromboembolism (VTE) involving platelet activation, immune dysregulation, and systemic inflammation. Nevertheless, their associations have not been well established. Methods and Results To examine the risk of incident VTE among patients with BP or PV, we performed a nationwide cohort study using Taiwan's National Health Insurance Research Database and enrolled 12 162 adults with BP or PV and 12 162 controls. A Cox regression model considering stabilized inverse probability weighting was used to calculate the hazard ratios (HRs) for incident VTE associated with BP or PV. To consolidate the findings, a meta-analysis that incorporated results from the present cohort study with previous literature was also conducted. Compared with controls, patients with BP or PV had an increased risk for incident VTE (HR, 1.87 [95% CI, 1.55-2.26]; P<0.001). The incidence of VTE was 6.47 and 2.20 per 1000 person-years in the BP and PV cohorts, respectively. The risk for incident VTE significantly increased among patients with BP (HR, 1.85 [95% CI, 1.52-2.24]; P<0.001) and PV (HR, 1.99 [95% CI, 1.02-3.91]; P=0.04). In the meta-analysis of 8 studies including ours, BP and PV were associated with an increased risk for incident VTE (pooled relative risk, 2.17 [95% CI, 1.82-2.62]; P<0.001). Conclusions BP and PV are associated with an increased risk for VTE. Preventive approaches and cardiovascular evaluation should be considered particularly for patients with BP or PV with concomitant risk factors such as hospitalization or immobilization.

Case Report: A Presentation of Early-Onset Immune-Mediated Bullous Pemphigoid in a Patient with Urothelial Cancer

Cutaneous immune-related adverse events (cirAEs) are the most common side effects of immune checkpoint inhibitor (ICI) therapy (30-50% for all grades). The vast majority of them are low or mild and can be treated without ICI interruption. Autoimmune blistering disorders, such as immune-mediated bullous pemphigoid (IBP), are rare (<1%) but potentially serious conditions that must be early detected. The onset generally occurs within the first months of the treatment, and it appears to be more common with antiprogrammed death-1 or antiprogrammed ligand 1 (anti-PD1/PDL1) than with anticytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4). We present a case of a three-day severe IBP onset after receiving the first cycle of atezolizumab. This exceptional early presentation could suggest the presence of some predisposing condition and demonstrates the need to better understand predictive toxicity-related biomarkers in candidate patients for immunotherapy.

Targeting type 2 inflammation in bullous pemphigoid: current and emerging therapeutic approaches

Bullous pemphigoid (BP) is one of the most common autoimmune bullous diseases and mainly affects an elderly population with multi-morbidity. Due to the frailty of many BP patients, existing treatment options are limited. The blisters associated with BP result from IgG and IgE autoantibodies binding to the central components of hemidesmosome, BP180, and BP230, stimulating a destructive inflammatory process. The known characteristic features of BP, such as intense pruritus, urticarial prodrome, peripheral eosinophilia, elevated IgE, as well as recent expanding evidence from in vitro and in vivo studies implicate type 2 inflammation as an important driver of BP pathogenesis. Type 2 inflammation is an inflammatory pathway involving a subset of CD4+ T cells that secrete IL-4, IL-5, and IL-13, IgE-secreting B cells, and granulocytes, such as eosinophils, mast cells, and basophils. It is believed that effectors in type 2 inflammation may serve as novel and effective treatment targets for BP. This review focuses on recent understandings of BP pathogenesis with a particular emphasis on the role of type 2 inflammation. We summarize current clinical evidence of using rituximab (B-cell depletion), omalizumab (anti-IgE antibody), and dupilumab (anti-IL-4/13 antibody) in the treatment of BP. The latest advances in emerging targeted therapeutic approaches for BP treatment are also discussed.

Eosinophils, Basophils, and Neutrophils in Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering skin disease, of which the incidence has increased in recent years. BP is characterized by circulating IgG and IgE autoantibodies against the hemidesmosomal proteins BP180 and BP230. Although autoantibodies trigger inflammatory cascades that lead to blister formation, effector cells and cell-mediated autoimmunity must also be considered as important factors in the pathogenesis of BP. The aim of this review is to outline the current knowledge on the role of eosinophils, basophils, and neutrophils in BP.

Adaptive and innate immune pathogenesis of bullous pemphigoid: A review

Bullous pemphigoid (BP) is an autoimmune blistering disease that primarily affects elderly individuals. The presentation of BP is heterogeneous, typically manifesting as microscopic subepidermal separation with a mixed inflammatory infiltrate. The mechanism of pemphigoid development is unclear. B cells play a major role in pathogenic autoantibody production, and T cells, type II inflammatory cytokines, eosinophils, mast cells, neutrophils, and keratinocytes are also implicated in the pathogenesis of BP. Here, we review the roles of and crosstalk between innate and adaptive immune cells in BP.

Bullous pemphigoid: The role of type 2 inflammation in its pathogenesis and the prospect of targeted therapy

Bullous pemphigoid (BP) is an autoimmune disease that mainly occurs in the elderly, severely affecting their health and life quality. Traditional therapy for BP is mainly based on the systemic use of corticosteroids, but long-term use of corticosteroids results in a series of side effects. Type 2 inflammation is an immune response largely mediated by group 2 innate lymphoid cells, type 2 T helper cells, eosinophils, and inflammatory cytokines, such as interleukin (IL)-4, IL-5 and IL-13. Among patients with BP, the levels of immunoglobulin E and eosinophils are significantly increased in the peripheral blood and skin lesions, suggesting that the pathogenesis is tightly related to type 2 inflammation. To date, various targeted drugs have been developed to treat type 2 inflammatory diseases. In this review, we summarize the general process of type 2 inflammation, its role in the pathogenesis of BP and potential therapeutic targets and medications related to type 2 inflammation. The content of this review may contribute to the development of more effective drugs with fewer side effects for the treatment of BP.

Emerging Biomarkers and Therapeutic Strategies for Refractory Bullous Pemphigoid

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disorder in the elderly. Systemic and topical use of glucocorticoids and immunosuppressants has been shown to be effective in most patients. However, refractory BP patients are challenged to clinicians with severe clinical symptoms, resistance to treatment, and high relapse rate. How to predict and assess the refractory and severity of bullous pemphigoid is the key issue in clinical practice, and the urgent need for precision medicine in refractory patients is driving the search for biomarkers and biologics. Recently, some biomarkers, such as the level of specific autoantibodies and released cytokines, have been proposed as the potential parameters to reflect the disease severity and predict the treatment response and relapse of refractory BP. Moreover, new biologics targeting pathogenic antibodies, complement, Th2 axis, eosinophils, and Th17 axis have shown potent efficacy on refractory BP. Here, we review the literature and give an overview of emerging biomarkers and therapeutic strategies for refractory bullous pemphigoid to improve the prognosis of the patient.

Plasma levels of D-dimer and fibrin degradation products correlate with bullous pemphigoid severity: a cross-sectional study

Bullous pemphigoid (BP), the most frequent blistering dermatosis in the elderly, is associated with increased mortality. The severity of BP can be assessed by detecting the anti-BP180 immunoglobulin G (IgG) concentration, but the lab test is not available in many community clinics. BP patients are usually in a hypercoagulable state with increased levels of D-dimer and fibrin degradation products (FDPs). We aimed to evaluate the use of D-dimer and FDPs in assessing BP severity. We compared the levels of plasma D-dimer, plasma FDPs, eosinophil counts, eosinophil cationic protein, and serum anti-BP180 IgG concentration between 48 typical BP patients and 33 Herpes zoster (HZ) patients (control group). Correlational analyses were conducted to determine the relationships between the lab values and common BP severity markers. The plasma D-dimer and FDP levels were higher in BP patients than in HZ controls (D-dimer: 3297 ± 2517 µg/L vs. 569.70 ± 412.40 µg/L; FDP: 9.74 ± 5.88 mg/L vs. 2.02 ± 1.69 mg/L, respectively, P < 0.0001). Significant positive correlations were found between D-dimer/FDP levels and BP severity markers (i.e. anti-BP180 IgG concentration [D-dimer: r = 0.3928, P = 0.0058; FDP: r = 0.4379, P = 0.0019] and eosinophil counts [D-dimer: r = 0.3625, P = 0.0013; FDP: r = 0.2880, P = 0.0472]) in BP patients. We also found an association between FDP and urticaria/erythema lesions (r = 0.3016, P = 0.0372), but no other BPDAI components. In 19 BP patients with complete remission after systemic glucocorticoid treatment, D-dimer and FDP levels decreased post-therapy (D-dimer: 5559 ± 7492 µg/L vs. 1738 ± 1478 µg/L; P < 0.0001; FDP: 11.20 ± 5.88 mg/L vs. 5.13 ± 3.44 mg/L; P = 0.0003), whereas they did not in BP patients with treatment resistant. Plasma D-dimer and FDP are convenient markers to evaluate BP severity assistant on BPDAI and eosinophil counts. FDP is also helpful for inflammatory lesions in BP patients.

Characterizing the proteome of bullous pemphigoid blister fluid utilizing tandem mass tag labeling coupled with LC-MS/MS

Bullous pemphigoid is an autoimmune blistering disease caused by autoantibodies against components of the cutaneous basement membrane zone. Autoantibodies lead to complement-dependent and -independent inflammation and blistering. Blister fluid is a valuable biologic resource, as it provides insight into both systemic and local microenvironment responses. Here, we utilized liquid chromatography with tandem mass spectrometry to characterize the bullous pemphigoid blister fluid proteome. We then depleted exosomes to better understand the exosomal versus non-exosomal proteome. We identified 339 proteins in the blister fluid of bullous pemphigoid patients. Gene ontology demonstrated enrichment of several key biologic processes including innate immune response, neutrophil degranulation, platelet degranulation, and complement activation. Exosome depletion resulted in a significant decrease in normalized reporter intensities of 192 proteins, consistent with our observation of a large number of exosomal proteins found in the blister fluid. We then compared the bullous pemphigoid blister fluid proteome to prior proteomic datasets in suction blister fluid, snake bites, and thermal burns, identifying 76 proteins unique to bullous pemphigoid. These include major basic protein, eosinophil peroxidase, galectin-10, and the immunoglobulin epsilon heavy constant region, consistent with tissue eosinophilia. We lastly validated several previously reported blister fluid exosomal components. Blister fluid in bullous pemphigoid contains a mixture of numerous biologic processes. While many of these processes are shared with blistering from alternative causes, we have identified several notable features unique to bullous pemphigoid.

Bullous Pemphigoid: Trigger and Predisposing Factors

Bullous pemphigoid (BP) is the most frequent autoimmune subepidermal blistering disease provoked by autoantibodies directed against two hemidesmosomal proteins: BP180 and BP230. Its pathogenesis depends on the interaction between predisposing factors, such as human leukocyte antigen (HLA) genes, comorbidities, aging, and trigger factors. Several trigger factors, such as drugs, thermal or electrical burns, surgical procedures, trauma, ultraviolet irradiation, radiotherapy, chemical preparations, transplants, and infections may induce or exacerbate BP disease. Identification of predisposing and trigger factors can increase the understanding of BP pathogenesis. Furthermore, an accurate anamnesis focused on the recognition of a possible trigger factor can improve prognosis by promptly removing it.

Eosinophilic Dermatoses: Recognition and Management

Eosinophilic dermatoses encompass a broad spectrum of diseases of different etiologies hallmarked by eosinophilic infiltration of the skin and/or mucous membranes, with or without associated blood eosinophilia. The wide range of dermatological manifestations of this spectrum, including nodules and plaques, pustules, blisters, ulcers, and urticarial lesions, is reflected in a non-univocal classification system. We identified six groups of eosinophilic dermatoses based on the predominant anatomic level of involvement: (1) epidermal; (2) of the dermal-epidermal junction; (3) dermal; (4) of the hypodermis and muscle fascia; (5) of the pilosebaceous unit; and (6) vascular/perivascular. We review clinicopathologic features and management of diseases belonging to each group, particularly: (1) pemphigus herpetiformis and atopic dermatitis as prototypes of the epidermal group; (2) bullous pemphigoid as prototypic eosinophilic dermatosis of the dermal-epidermal junction; (3) eosinophilic cellulitis (Wells syndrome), hypereosinophilic syndromes, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, eosinophilic dermatosis of hematologic malignancy and chronic spontaneous urticaria as paradigmatic dermal eosinophilic dermatoses; (4) eosinophilic fasciitis as an eosinophilic dermatosis with predominant involvement of the hypodermis and muscle fascia; (5) eosinophilic pustular folliculitis as a model of the pilosebaceous unit involvement; and (6) granuloma faciale, angiolymphoid hyperplasia with eosinophilia, and eosinophilic granulomatosis with polyangiitis, belonging to the vascular/perivascular group.

Eosinophils in Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disorder with substantial morbidity and mortality. BP is regarded as a disorder driven by IgG due to BP180 and BP230 IgG autoantibodies, yet, new advances highlight the function of eosinophils and IgE autoantibodies in BP. Evidence supports that eosinophils are involved in BP pathogenesis, notably, these include the presence of IL-5, eotaxin, and eosinophil-colony stimulating factor in blister fluid, peripheral blood eosinophilia is present in nearly 50% of affected patients, eosinophils are found against the dermo-epidermal junction (DEJ) when BP serum is present, metalloprotease-9 is secreted by eosinophils at blister sites, blister fluid of BP patients contains eosinophil granule proteins which are located along the lamina lucida of the BMZ in patients with BP and correspond with disease clinically, eosinophil extracellular traps (EET) have been linked to DEJ splitting, IL-5 activated eosinophils cause DEJ separation when BP serum is present, and eosinophils are requisite to drive anti-BP180 IgE mediated blistering of the skin. Yet, the mechanism whereby eosinophils contribute to the pathogenesis of BP remains to be explored. In this review, we examine the role of eosinophils in BP while offering a basis to explain the pathomechanisms of eosinophils in BP.

Factors associated with the activity and severity of bullous pemphigoid: a review

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease. It usually affects people older than 70 years of age. The two main autoantigens are BP180 and BP230, both of which are components of hemidesmosomes. Immunoglobulin (Ig)G and IgE autoantibodies to BP180 detected by the enzyme-linked immunoassay (ELISA) show close associations with the activity and severity of BP. In addition, inflammatory cells (eosinophils, neutrophils and mast cells) and cytokines (e.g. interleukins and CC chemokine ligands) play an important part in the pathogenesis, activity and severity of BP. We summarized the potential contribution of each factor postulated to be associated with the activity and severity of BP, and provide guidance for clinicians to pay timely and close attention to such parameters. This review may also promote the development of novel therapies for BP.Key MessagesBullous Pemphigoid Disease Area Index (BPDAI) is a scoring system which can reflect the extent of clinical involvement of BP patients.The titres of IgE autoantibodies and IgG autoantibodies against the NC16A domain of BP180 are closely correlated with the activity and severity of BP.Many inflammatory cells and molecules, such as eosinophils and interleukins, can also reflect the activity and severity of BP.

Targeted Therapies for Autoimmune Bullous Diseases: Current Status

Autoimmune bullous skin disorders are rare but meaningful chronic inflammatory diseases, many of which had a poor or devastating prognosis prior to the advent of immunosuppressive drugs such as systemic corticosteroids, which down-regulate the immune pathogenesis in these disorders. Glucocorticoids and adjuvant immunosuppressive drugs have been of major benefit for the fast control of most of these disorders, but their long-term use is limited by major side effects such as blood cytopenia, osteoporosis, diabetes mellitus, hypertension, and gastrointestinal ulcers. In recent years, major efforts were made to identify key elements in the pathogenesis of autoimmune bullous disorders, leading to the identification of their autoantigens, which are mainly located in desmosomes (pemphigus) and the basement membrane zone (pemphigoids). In the majority of cases, immunoglobulin G, and to a lesser extent, immunoglobulin A autoantibodies directed against distinct cutaneous adhesion molecules are directly responsible for the loss of cell-cell and cell-basement membrane adhesion, which is clinically related to the formation of blisters and/or erosions of the skin and mucous membranes. We describe and discuss novel therapeutic strategies that directly interfere with the production and regulation of pathogenic autoantibodies (rituximab), their catabolism (intravenous immunoglobulins), and their presence in the circulation and extravascular tissues such as the skin (immunoadsorption), leading to a significant amelioration of disease. Moreover, we show that these novel therapies have pleiotropic effects on various proinflammatory cells and cytokines. Recent studies in bullous pemphigoid suggest that targeting of immunoglobulin E autoantibodies (omalizumab) may be also beneficial. In summary, the introduction of targeted therapies in pemphigus and pemphigoid holds major promise because of the high efficacy and fewer side effects compared with conventional global immunosuppressive therapy.

New Insights Into the Pathogenesis of Bullous Pemphigoid: 2019 Update

There are several lines of evidence indicating that the physiopathological bases of bullous pemphigoid (BP), the most common subepidermal autoimmune bullous disease, are hallmarked by the production of autoantibodies directed against the hemidesmosomal anchoring proteins BP180 and BP230. In contrast to the robustness of the latter assumption, the multifaceted complexity of upstream and downstream mechanisms implied in the pathogenesis of BP remains an area of intense speculation. So far, an imbalance between T regulatory cells and autoreactive T helper (Th) cells has been regarded as the main pathogenic factor triggering the autoimmune response in BP patients. However, the contributory role of signaling pathways fostering the B cell stimulation, such as Toll-like receptor activation, as well as that of ancillary inflammatory mechanisms responsible for blister formation, such as Th17 axis stimulation and the activation of the coagulation cascade, are still a matter of debate. In the same way, the pathomechanisms implied in the loss of dermal-epidermal adhesion secondary to autoantibodies binding are not fully understood. Herein, we review in detail the current concepts and controversies on the complex pathogenesis of BP, shedding light on the most recent theories emerging from the literature.

Coagulation and Skin Autoimmunity

Several lines of evidence indicate that the immune system, inflammation, and coagulation are simultaneously activated in autoimmune and immune-mediated skin diseases. Pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha induce the expression of the main initiator of coagulation, i.e., tissue factor. The proteases of coagulation in turn act on protease-activated receptors inducing the expression of various pro-inflammatory cytokines triggering inflammation. The cross-talk among immune system, inflammation, and coagulation amplifies and maintains the activation of all three pathways. This review focuses on three skin disorders as chronic spontaneous urticaria (CSU), angioedema, and bullous pemphigoid (BP), in which the relationships among the three systems have been investigated or their clinical consequences are relevant. Markers of thrombin generation, fibrinolysis, and inflammation have been reported to be increased in the plasma during flares of CSU and angioedema, as well as in the active phase of BP, with the marker levels reverting to normal during remission. The coagulation activation seems to be important only at local level in CSU and angioedema while both at local and systemic levels in BP which is the only condition associated with an increased thrombotic risk. The prothrombotic state in autoimmune skin diseases raises the question of the indication of anticoagulant treatment, particularly in the presence of other cardiovascular risk factors.

Biomarkers related to bullous pemphigoid activity and outcome

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease of the skin. Investigation of the BP-associated pathophysiological processes during the last decades showed that the generation of autoantibodies directed against the hemidesmosome proteins BP180 and BP230, a hallmark of the BP-associated autoimmune response, leads to the recruitment of inflammatory immune cells at the dermal-epidermal junction, and subsequently to the release of a large amount of inflammatory molecules involved in blister formation. Analysis in transversal and longitudinal studies of autoantibodies and inflammatory molecules production both at the time of diagnosis and under treatment was mainly performed within the serum but also in the blister fluid. Some autoimmune or inflammatory molecules expression was related to the presence of clinical signs, while others were mere bystanders. In this review, we focused on the autoimmune and inflammatory molecules that have been identified as potential biomarkers of BP development and outcome.

Mechanisms of pathogenic effects of eosinophil cationic protein and eosinophil-derived neurotoxin on human keratinocytes

Cutaneous deposition of eosinophil degranulation proteins is a major feature of eosinophil-rich cutaneous diseases including bullous pemphigoid (BP). We sought to better understand the effect of two of these proteins - eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN), on human keratinocytes using the Het-1A cell line. To evaluate expression of key cytokines and chemokines observed in BP as well as metal metalloprotease 9 (MMP9), we performed qPCR and in-cell Western assays on cells treated with either ECP or EDN. We further evaluated the effect of ECP and EDN on keratinocyte survival, generation of reactive oxygen species (ROS) and apoptosis. Lastly, we assessed ECP and EDN's ability to induce keratinocyte detachment from provisional matrix. Treatment of keratinocytes with ECP and EDN resulted in significant increases in IL-5, eotaxin-1 and CCL5 (RANTES) expression at both mRNA and protein levels, but not IL-17 or IL-31. ECP and EDN also upregulate MMP9 production. Inhibiting MMP9, we confirmed that keratinocyte expression of IL-5, eotaxin-1 and RANTES was independent from MMP9. Both ECP and EDN were cytotoxic to keratinocytes, inducing ROS formation and apoptosis through a mitochondrion-dependent pathway as evidenced by results of terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) and cytochrome c release assays, respectively. ECP but not EDN led to significant keratinocyte detachment from provisional matrix. These findings demonstrate that the pathogenic effects of ECP and EDN in BP may result from their direct action on keratinocytes, and as such may became a target for future therapies in eosinophil-rich cutaneous diseases.

The Role of Eosinophils in Bullous Pemphigoid: A Developing Model of Eosinophil Pathogenicity in Mucocutaneous Disease

Bullous pemphigoid (BP) is an autoimmune blistering disease which carries a significant mortality and morbidity. While historically BP has been characterized as an IgG driven disease mediated by anti-BP180 and BP230 IgG autoantibodies, developments in recent years have further elucidated the role of eosinophils and IgE autoantibodies. In fact, eosinophil infiltration and eosinophilic spongiosis are prominent features in BP. Several observations support a pathogenic role of eosinophils in BP: IL-5, eotaxin, and eosinophil-colony stimulating factor are present in blister fluid; eosinophils line the dermo-epidermal junction (DEJ) in the presence of BP serum, metalloprotease-9 is released by eosinophils at the site of blisters; eosinophil degranulation proteins are found on the affected basement membrane zone as well as in serum corresponding with clinical disease; eosinophil extracellular DNA traps directed against the basement membrane zone are present, IL-5 activated eosinophils cause separation of the DEJ in the presence of BP serum; and eosinophils are the necessary cell required to drive anti-BP180 IgE mediated skin blistering. Still, it is likely that eosinophils contribute to the pathogenesis of BP in numerous other ways that have yet to be explored based on the known biology of eosinophils. We herein will review the role of eosinophils in BP and provide a framework for understanding eosinophil pathogenic mechanisms in mucocutaneous disease.

BP180 Is Critical in the Autoimmunity of Bullous Pemphigoid

Bullous pemphigoid (BP) is by far the most common autoimmune blistering dermatosis that mainly occurs in the elderly. The BP180 is a transmembrane glycoprotein, which is highly immunodominant in BP. The structure and location of BP180 indicate that it is a significant autoantigen and plays a key role in blister formation. Autoantibodies from BP patients react with BP180, which leads to its degradation and this has been regarded as the central event in BP pathogenesis. The consequent blister formation involves the activation of complement-dependent or -independent signals, as well as inflammatory pathways induced by BP180/anti-BP180 autoantibody interaction. As a multi-epitope molecule, BP180 can cause dermal-epidermal separation via combining each epitope with specific immunoglobulin, which also facilitates blister formation. In addition, some inflammatory factors can directly deplete BP180, thereby leading to fragility of the dermal-epidermal junction and blister formation. This review summarizes recent investigations on the role of BP180 in BP pathogenesis to determine the potential targets for the treatment of patients with BP.

Analysis of serum markers of cellular immune activation in patients with bullous pemphigoid

Experimental models of bullous pemphigoid (BP), the most frequent subepidermal autoimmune bullous disease, revealed that the immune response leading to blister formation represents an incompletely understood complex process involving different inflammatory cells. In contrast to previous reports commonly focusing on limited molecular and cellular phenotypes of the disease, the aim of this study was to investigate a broad spectrum of markers of cellular immune activation in patients with BP. We found that serum levels of soluble CD4, myeloperoxidase, S100A12, eosinophil cationic protein and soluble P-selectin were significantly elevated in patients with active BP compared with normal controls. Mast cell tryptase and neopterin serum levels significantly decreased at the time of clinical remission of the patients. Additionally, serum concentrations of soluble IL-2 receptor, mast cell tryptase and soluble P-selectin were significantly associated with levels of circulating anti-BP180 autoantibodies. Our findings confirm and extend previous reports suggesting some concomitant involvement of a panel of molecules representative for a wide spectrum of cellular players (T cells, mast cells, neutrophils, eosinophils, macrophages and platelets) orchestrating the inflammatory reaction in BP. These data may favour the employment of broad-spectrum or combined immunosuppressants, potentially together with an anticoagulant treatment, over cell- or molecule-specific targeted therapy in patients with this disorder.

Eosinophils in Autoimmune Diseases

Eosinophils are multifunctional granulocytes that contribute to initiation and modulation of inflammation. Their role in asthma and parasitic infections has long been recognized. Growing evidence now reveals a role for eosinophils in autoimmune diseases. In this review, we summarize the function of eosinophils in inflammatory bowel diseases, neuromyelitis optica, bullous pemphigoid, autoimmune myocarditis, primary biliary cirrhosis, eosinophilic granulomatosis with polyangiitis, and other autoimmune diseases. Clinical studies, eosinophil-targeted therapies, and experimental models have contributed to our understanding of the regulation and function of eosinophils in these diseases. By examining the role of eosinophils in autoimmune diseases of different organs, we can identify common pathogenic mechanisms. These include degranulation of cytotoxic granule proteins, induction of antibody-dependent cell-mediated cytotoxicity, release of proteases degrading extracellular matrix, immune modulation through cytokines, antigen presentation, and prothrombotic functions. The association of eosinophilic diseases with autoimmune diseases is also examined, showing a possible increase in autoimmune diseases in patients with eosinophilic esophagitis, hypereosinophilic syndrome, and non-allergic asthma. Finally, we summarize key future research needs.

The biochemistry of blister fluid from pediatric burn injuries: proteomics and metabolomics aspects

Burn injury is a prevalent and traumatic event for pediatric patients. At present, the diagnosis of burn injury severity is subjective and lacks a clinically relevant quantitative measure. This is due in part to a lack of knowledge surrounding the biochemistry of burn injuries and that of blister fluid. A more complete understanding of the blister fluid biochemistry may open new avenues for diagnostic and prognostic development. Burn insult induces a highly complex network of signaling processes and numerous changes within various biochemical systems, which can ultimately be examined using proteome and metabolome measurements. This review reports on the current understanding of burn wound biochemistry and outlines a technical approach for 'omics' profiling of blister fluid from burn wounds of differing severity.

IgE-mediated mechanisms in bullous pemphigoid and other autoimmune bullous diseases

Autoimmune bullous diseases (AIBDs) are characterized by autoantibodies against structural proteins of the dermal-epidermal junction (in pemphigoid diseases) and the epidermal/ epithelial desmosomes (in pemphigus diseases). By far, the most common AIBD is bullous pemphigoid, which is immunopathologically characterized by autoantibodies against BP180 (type XVII collagen) and BP230. IgG and, to a lesser extent, IgA autoantibodies are the major autoantibody isotypes in these disorders. IgE autoantibodies are increasingly reported in particular in bullous pemphigoid. The development of specific and sensitive anti-BP180 IgE ELISA systems, the report of two experimental murine models employing IgE autoantibodies against BP180, and the successful treatment of bullous pemphigoid with the anti-IgE antibody omalizumab have raised interest in the role of IgE autoantibodies and the modulation of their production in AIBDs. Here, the relevance of IgE autoantibodies in the diagnosis, pathophysiology, and treatment decisions of AIBDs, with a focus on bullous pemphigoid, is reviewed.

Neurological disorders in patients with bullous pemphigoid: clinical and experimental investigations

BACKGROUND

Previous studies have shown that patients with bullous pemphigoid (BP) are more likely to have neurological diseases (ND).

OBJECTIVES

To compare clinical findings in BP patients with and without ND and to investigate BP180 autoantibody binding in different neuronal tissues of mammalians.

METHODS

Our database was searched for clinical findings of in-patients with the definitive diagnosis of BP. Moreover, brain tissue of mammalians was treated with serum of BP patients with elevated BP180 autoantibodies using biochip mosaics.

RESULTS

Of 85/161 (52.8%) patients had a history of at least one ND (BP+ND). BP180 (P = 0.018), eosinophils (P = 0.043) and patients' accommodation in nursing homes (P < 0.0001) remained in the logistic regression model as significant independent predictors for the presence of ND in patients with BP. Subgroup analysis of community-dwelling BP patients revealed 25/93 (26.9%) patients with ND. In this population, the presence of ND also significantly correlated with BP180 (r = 0.26; P = 0.0003) and eosinophils (r = 0.19; P = 0.0087). In the animal model, no BP180-specific immunofluorescence could be detected.

CONCLUSIONS

Our data support results of previous studies detecting significantly increased frequency of ND in BP patients. We have shown that raised BP180 titres and blood eosinophils are independent predictors for the presence of ND in BP patients. However, our experimental data do not support previous results indicating that specific binding of BP180 antibodies in neuronal tissue plays a pathogenetic role in ND.