Characteristics of Pruritus in Bullous Pemphigoid and Impact on Quality of Life: A Prospective Cohort Study

Pruritus is a common symptom of bullous pemphigoid (BP), but has been poorly studied. The aim of this study was to analyse the characteristics of pruritus in patients with BP and its impact on their quality of life. A multicentre prospective observational study (in 15 French hospitals) was performed. A total of 60 patients were included, with a mean age of 77.4 years. Pruritus occurred daily in 85% of patients, with a mean pruritus intensity of 5.2/10. Tingling sensations were present in 72.4% of patients and burning sensations in 68.9%. Pruritus was exacerbated by stress, fatigue and xerosis. The mean ItchyQol score was 56.2/110 and the mean 5-D Itch Scale score was 16.5/25. The severity of pruritus was not related to age, sex, BP activity score, eosinophilia, or anti-BP230 and anti-BP180 autoantibodies. This study revealed that pruritus in BP is poorly tolerated and is an important cause of impaired quality of life.

Effects of Plectin Depletion on Keratin Network Dynamics and Organization

The keratin intermediate filament cytoskeleton protects epithelial cells against various types of stress and is involved in fundamental cellular processes such as signaling, differentiation and organelle trafficking. These functions rely on the cell type-specific arrangement and plasticity of the keratin system. It has been suggested that these properties are regulated by a complex cycle of assembly and disassembly. The exact mechanisms responsible for the underlying molecular processes, however, have not been clarified. Accumulating evidence implicates the cytolinker plectin in various aspects of the keratin cycle, i.e., by acting as a stabilizing anchor at hemidesmosomal adhesion sites and the nucleus, by affecting keratin bundling and branching and by linkage of keratins to actin filament and microtubule dynamics. In the present study we tested these hypotheses. To this end, plectin was downregulated by shRNA in vulvar carcinoma-derived A431 cells. As expected, integrin β4- and BPAG-1-positive hemidesmosomal structures were strongly reduced and cytosolic actin stress fibers were increased. In addition, integrins α3 and β1 were reduced. The experiments furthermore showed that loss of plectin led to a reduction in keratin filament branch length but did not alter overall mechanical properties as assessed by indentation analyses using atomic force microscopy and by displacement analyses of cytoplasmic superparamagnetic beads using magnetic tweezers. An increase in keratin movement was observed in plectin-depleted cells as was the case in control cells lacking hemidesmosome-like structures. Yet, keratin turnover was not significantly affected. We conclude that plectin alone is not needed for keratin assembly and disassembly and that other mechanisms exist to guarantee proper keratin cycling under steady state conditions in cultured single cells.

Immunoadsorber for specific apheresis of autoantibodies in the treatment of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering skin disease associated with autoantibodies against two hemidesmosomal proteins, BP180 (type XVII collagen) and BP230. As the pathogenic relevance of antibodies against the immunodominant NC16A domain of BP180 has been clearly demonstrated, specific removal of these antibodies should be a rational therapeutic approach. Here, we evaluated three recombinant forms of bacterially produced BP180 NC16A, a monomer, trimer, and tetramer, together with different matrices for their efficacy to specifically adsorb autoantibodies from BP plasma samples. An adsorber consisting of NC16A-trimer coupled to NHS-activated Sepharose 4 Fast Flow revealed satisfying adsorption rates and a high specificity. The NC16A-trimer adsorber was regenerable and autoclavable. It has the potential to be used for specific immunoadsorption to treat severe and refractory BP and other pemphigoid diseases associated with BP180 NC16A reactivity.

The molecular architecture of hemidesmosomes, as revealed with super-resolution microscopy

Hemidesmosomes have been extensively studied with immunofluorescence microscopy, but owing to its limited resolution, the precise organization of hemidesmosomes remains poorly understood. We studied hemidesmosome organization in cultured keratinocytes with two- and three-color super-resolution microscopy. We observed that, in the cell periphery, nascent hemidesmosomes are associated with individual keratin filaments and that β4 integrin (also known as ITGB4) is distributed along, rather than under, keratin filaments. By applying innovative methods to quantify molecular distances, we demonstrate that the hemidesmosomal plaque protein plectin interacts simultaneously and asymmetrically with β4 integrin and keratin. Furthermore, we show that BP180 (BPAG2, also known as collagen XVII) and BP230 (BPAG1e, an epithelial splice variant of dystonin) are characteristically arranged within hemidesmosomes with BP180 surrounding a central core of BP230 molecules. In skin cross-sections, hemidesmosomes of variable sizes could be distinguished with BP230 and plectin occupying a position in between β4 integrin and BP180, and the intermediate filament system. In conclusion, our data provide a detailed view of the molecular architecture of hemidesmosomes in cultured keratinocytes and skin.

Positive Direct Immunofluorescence Is of Better Value than ELISA-BP180 and ELISA-BP230 Values for the Prediction of Relapse after Treatment Cessation in Bullous Pemphigoid: A Retrospective Study of 97 Patients

BACKGROUND

ELISA-BP180 values and direct immunofluorescence (DIF) are prognostic factors for relapse after treatment cessation in bullous pemphigoid (BP).

OBJECTIVE

To determine the relevance of ELISA-BP230 antibodies for predicting relapse 6 months after treatment cessation.

METHODS

We retrospectively selected patients with BP and available data from ELISA-BP180 and -BP230 and DIF performed at treatment cessation. The rate of relapse was calculated at 6 months. We compared ELISA-BP180 and -BP230 values and DIF in patients with relapse and remission.

RESULTS

We included 97 patients. At 6 months, 25.6% of patients showed relapse. The proportion of patients with an ELISA-BP230 value ≥27 UA/ml was higher, but not significantly, for those with relapse than for those with remission (p = 0.11). The frequency of positive DIF findings was significantly higher for patients with relapse (p = 0.005).

CONCLUSION

DIF is of better value than ELISA-BP180 and -230 tests to predict relapse after treatment cessation in BP.

Diagnostic accuracy of BP180 NC16a and BP230-C3 ELISA in serum and saliva of patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is a subepidermal blistering disease, characterized by autoantibodies directed against BP180 and BP230. Collecting saliva is an easy and painless way of obtaining biological samples, and can be used for diagnosis of autoimmune diseases.

AIM

To compare the diagnostic accuracy of serum and salivary BP180-NC16a and BP230-C3 in the initial diagnosis of BP.

METHODS

We assessed 50 patients newly diagnosed with BP and 50 healthy controls. The diagnosis of BP was confirmed based on clinical, histopathological and immunofluorescence findings. Serum and saliva samples were collected from both groups, and BP180 and BP230 titres were assessed using commercially available ELISA kits.

RESULTS

Using serum, the sensitivity of the serum BP180 and BP230 ELISA assays was 88% and 48%, respectively, and the specificity of both was 96%. Using saliva with the cutoff value proposed by the manufacturer, sensitivity was 56.2% and 14.6%, and specificity was 98% and 100%, respectively. Using the best calculated cutoff for saliva, sensitivity increased to 87.5% and 77.1%, and specificity to 96% and 62%, respectively. There was a significant correlation between serum and saliva BP180 levels and the severity of skin disease. Both serum and saliva BP230 levels were significantly higher in patients with mucosal involvement.

CONCLUSION

Serum BP180 NC16a ELISA is a sensitive and specific test for the initial diagnosis of BP, whereas serum BP230-C3 ELISA is highly specific, but less sensitive. Saliva may be a noninvasive and convenient alternative for use in the BP180 NC16a ELISA to diagnose BP.

IgE autoantibodies in bullous pemphigoid: supporting role, or leading player?

Bullous pemphigoid (BP) is a common autoimmune blistering skin disease in which two hemidesmosomal components--the transmembrane collagen XVII (BP180 or BPAG2) and the plakin family protein BP230 (BPAG1)--are targeted by autoimmunity. Of these, collagen XVII (COL17) is thought to be a major autoantigen, and vital roles of IgG autoantibodies in blister formation have been elucidated. However, BP shows distinct features, including pruritic urticarial erythema and eosinophilic infiltration, which may be independent of IgG-mediated autoimmunity. Recently, it has been revealed that sera from certain patients with BP contain IgE autoantibodies to COL17 and that IgE autoantibodies bind to peri-lesional dermal-epidermal junctions. Mouse models have demonstrated that IgE antibodies to COL17 induce erythema and eosinophilic infiltration in skin. In addition, the successful treatment of severe BP with omalizumab, a humanized monoclonal antibody targeting IgE, has been reported. These findings suggest that both IgG and IgE autoantibodies to COL17 may be involved in the BP pathogenesis. This article summarizes IgE-mediated autoimmunity to COL17 in BP.

Disruption in the autophagic process underlies the sensory neuropathy in dystonia musculorum mice

A homozygous mutation in the DST (dystonin) gene causes a newly identified lethal form of hereditary sensory and autonomic neuropathy in humans (HSAN-VI). DST loss of function similarly leads to sensory neuron degeneration and severe ataxia in dystonia musculorum (Dst(dt)) mice. DST is involved in maintaining cytoskeletal integrity and intracellular transport. As autophagy is highly reliant upon stable microtubules and motor proteins, we assessed the influence of DST loss of function on autophagy using the Dst(dt-Tg4) mouse model. Electron microscopy (EM) revealed an accumulation of autophagosomes in sensory neurons from these mice. Furthermore, we demonstrated that the autophagic flux was impaired. Levels of LC3-II, a marker of autophagosomes, were elevated. Consequently, Dst(dt-Tg4) sensory neurons displayed impaired protein turnover of autophagosome substrate SQTSM1/p62 and of polyubiquitinated proteins. Interestingly, in a previously described Dst(dt-Tg4) mouse model that is partially rescued by neuronal specific expression of the DST-A2 isoform, autophagosomes, autolysosomes, and damaged organelles were reduced when compared to Dst(dt-Tg4) mutant mice. LC3-II, SQTSM1, polyubiquitinated proteins and autophagic flux were also restored to wild-type levels in the rescued mice. Finally, a significant decrease in DNAIC1 (dynein, axonemal, intermediate chain 1; the mouse ortholog of human DNAI1), a member of the DMC (dynein/dynactin motor complex), was noted in Dst(dt-Tg4) dorsal root ganglia and sensory neurons. Thus, DST-A2 loss of function perturbs late stages of autophagy, and dysfunctional autophagy at least partially underlies Dst(dt) pathogenesis. We therefore conclude that the DST-A2 isoform normally facilitates autophagy within sensory neurons to maintain cellular homeostasis.

BPAG1a and b associate with EB1 and EB3 and modulate vesicular transport, Golgi apparatus structure, and cell migration in C2.7 myoblasts

BPAG1a and BPAG1b (BPAG1a/b) constitute two major isoforms encoded by the dystonin (Dst) gene and show homology with MACF1a and MACF1b. These proteins are members of the plakin family, giant multi-modular proteins able to connect the intermediate filament, microtubule and microfilament cytoskeletal networks with each other and to distinct cell membrane sites. They also serve as scaffolds for signaling proteins that modulate cytoskeletal dynamics. To gain better insights into the functions of BPAG1a/b, we further characterized their C-terminal region important for their interaction with microtubules and assessed the role of these isoforms in the cytoskeletal organization of C2.7 myoblast cells. Our results show that alternative splicing does not only occur at the 5′ end of Dst and Macf1 pre-mRNAs, as previously reported, but also at their 3′ end, resulting in expression of additional four mRNA variants of BPAG1 and MACF1. These isoform-specific C-tails were able to bundle microtubules and bound to both EB1 and EB3, two microtubule plus end proteins. In the C2.7 cell line, knockdown of BPAG1a/b had no major effect on the organization of the microtubule and microfilament networks, but negatively affected endocytosis and maintenance of the Golgi apparatus structure, which became dispersed. Finally, knockdown of BPAG1a/b caused a specific decrease in the directness of cell migration, but did not impair initial cell adhesion. These data provide novel insights into the complexity of alternative splicing of Dst pre-mRNAs and into the role of BPAG1a/b in vesicular transport, Golgi apparatus structure as well as in migration in C2.7 myoblasts.

[Bullous pemphigoid: diagnosis and therapy]

Bullous pemphigoid is the most common autoimmune bullous skin disease which occurs more often at higher age. Clinically it presents with tense blisters and eczematous lesions combined with severe pruritus. The pemphigoid-like diseases include mucous membrane pemphigoid, pemphigoid gestationis and linear IgA disease. Diagnosis is based on immunofluorescence microscopy and confirmatory tests (ELISA, immunoblotting). Classical bullous pemphigoid presents with IgG autoantibodies against BP180 and BP230. Treatment includes topical and systemic corticosteroids and adjuvant immunosuppressants.

BP180- and BP230-specific IgG autoantibodies in pruritic disorders of the elderly: a preclinical stage of bullous pemphigoid?

Pruritus increasingly occurs in the elderly population and is associated with a variety of dermatoses of mixed aetiology. Clinical and experimental evidence suggests that senile pruritus may be linked to autoimmune events initiated by loss of self-tolerance against cutaneous autoantigens, which is facilitated by immune ageing processes. T-cell immunity, which underpins the production of pathogenic autoantibodies in autoimmune diseases, is deregulated by immune senescence thereby leading to autoimmune disorders such as bullous pemphigoid (BP). High mortality rates of BP combined with steadily increasing incidence emphasize the need for an effective diagnostic strategy at an early stage. We summarize here the current understanding of immunological alterations during the ageing process, thereby focusing on aberrant T-cell responses against the basement membrane antigens BP180 and BP230, which may eventually lead to the clinical outcome of BP.

Isolation of a hemidesmosome-rich fraction from a human squamous cell carcinoma cell line

Hemidesmosomes are cell-to-matrix adhesion complexes anchoring keratinocytes to basement membranes. For the first time, we present a method to prepare a fraction from human cultured cells that are highly enriched in hemidesmosomal proteins. Using DJM-1 cells derived from human squamous cell carcinoma, accumulation of hemidesmosomes was observed when these cells were cultured for more than 10 days in a commercial serum-free medium without supplemental calcium. Electron microscopy demonstrated that numerous electron-dense adhesion structures were present along the basal cell membranes of DJM-1 cells cultured under the aforementioned conditions. After removing cellular materials using an ammonia solution, hemidesmosomal proteins and deposited extracellular matrix were collected and separated by electrophoresis. There were eight major polypeptides, which were determined to be plectin, BP230, BP180, integrin α6 and β4 subunits, and laminin-332 by immunoblotting and mass spectrometry. Therefore, we designated this preparation as a hemidesmosome-rich fraction. This fraction contained laminin-332 exclusively in its unprocessed form, which may account for the promotion of laminin deposition, and minimal amounts of Lutheran blood group protein, a nonhemidesmosomal transmembrane protein. This hemidesmosome-rich fraction would be useful not only for biological research on hemidesmosomes but also for developing a serum test for patients with blistering skin diseases.

Transgenic expression of neuronal dystonin isoform 2 partially rescues the disease phenotype of the dystonia musculorum mouse model of hereditary sensory autonomic neuropathy VI

A newly identified lethal form of hereditary sensory and autonomic neuropathy (HSAN), designated HSAN-VI, is caused by a homozygous mutation in the bullous pemphigoid antigen 1 (BPAG1)/dystonin gene (DST). The HSAN-VI mutation impacts all major neuronal BPAG1/dystonin protein isoforms: dystonin-a1, -a2 and -a3. Homozygous mutations in the murine Dst gene cause a severe sensory neuropathy termed dystonia musculorum (dt). Phenotypically, dt mice are similar to HSAN-VI patients, manifesting progressive limb contractures, dystonia, dysautonomia and early postnatal death. To obtain a better molecular understanding of disease pathogenesis in HSAN-VI patients and the dt disorder, we generated transgenic mice expressing a myc-tagged dystonin-a2 protein under the regulation of the neuronal prion protein promoter on the dt(Tg4/Tg4) background, which is devoid of endogenous dystonin-a1 and -a2, but does express dystonin-a3. Restoring dystonin-a2 expression in the nervous system, particularly within sensory neurons, prevented the disorganization of organelle membranes and microtubule networks, attenuated the degeneration of sensory neuron subtypes and ameliorated the phenotype and increased life span in these mice. Despite these improvements, complete rescue was not observed likely because of inadequate expression of the transgene. Taken together, this study provides needed insight into the molecular basis of the dt disorder and other peripheral neuropathies including HSAN-VI.

IgG antibodies against immunodominant C-terminal epitopes of BP230 do not induce skin blistering in mice

Bullous pemphigoid, the most common autoimmune blistering disease in Western Europe and the USA is characterized by the presence of circulating and tissue-bound autoantibodies against the hemidesmosomal proteins BP230 and BP180/collagen XVII. After binding to their target antigens at the basement membrane of the dermal-epidermal junction these autoantibodies are thought to trigger an inflammatory cascade comprising complement- and granulocyte-dependent reactions that result in tissue damage. Whereas the role of anti-BP180 antibodies has been extensively characterized, few and conflicting data is available on the contribution of anti-BP230 antibodies to bullous pemphigoid pathogenesis. Therefore, we addressed in the present study the role of autoantibodies to BP230 in experimental bullous pemphigoid. Rabbit polyclonal antibodies generated against epitopes of the C-terminal fragment of murine BP230 bound to the basement membrane and activated the complement system ex vivo. Affinity-purified antibodies were subsequently subcutaneously transferred into neonatal and adult BALB/c mice. In vivo, we observed a dose-dependent binding of transferred antibodies in the murine skin; however, there was no complement activation and these mice showed no clinical or histological signs of inflammatory disease, in contrast to mice receiving anti-BP180 antibodies. We further conducted ex vivo experiments and demonstrated that rabbit IgG anti-BP230-specific antibodies, in contrast to antibodies from bullous pemphigoid patients or rabbit IgG anti-BP180 antibodies used as positive controls, did not activate human granulocytes to induce dermal-epidermal separation in skin cryosections. Our present findings demonstrate that antibodies against BP230 are non-pathogenic in experimental models of bullous pemphigoid and suggest that proper activation of the complement and granulocytes represent prerequisites for conferring bullous pemphigoid autoantibodies their tissue destructive potential.

Expression microarray analysis reveals alternative splicing of LAMA3 and DST genes in head and neck squamous cell carcinoma

Purpose

Prior studies have demonstrated tumor-specific alternative splicing events in various solid tumor types. The role of alternative splicing in the development and progression of head and neck squamous cell carcinoma (HNSCC) is unclear. Our study queried exon-level expression to implicate splice variants in HNSCC tumors.

Experimental Design

We performed a comparative genome-wide analysis of 44 HNSCC tumors and 25 uvulopalatopharyngoplasty (UPPP) tissue samples at an exon expression level. In our comparison we ranked genes based upon a novel score—the Maximum-Minimum Exon Score (MMES) – designed to predict the likelihood of an alternative splicing event occurring. We validated predicted alternative splicing events using quantitative RT-PCR on an independent cohort.

Results

After MMES scoring of 17,422 genes, the top 900 genes with the highest scores underwent additional manual inspection of expression patterns in a graphical analysis. The genes LAMA3, DST, VEGFC, SDHA, RASIP1, and TP63 were selected for further validation studies because of a high frequency of alternative splicing suggested in our graphical analysis, and literature review showing their biological relevance and known splicing patterns. We confirmed TP63 as having dominant expression of the short DeltaNp63 isoform in HNSCC tumor samples, consistent with prior reports. Two of the six genes (LAMA3 and DST) validated by quantitative RT-PCR for tumor-specific alternative splicing events (Student's t test, P<0.001).

Conclusion

Alternative splicing events of oncologically relevant proteins occur in HNSCC. The number of genes expressing tumor-specific splice variants needs further elucidation, as does the functional significance of selective isoform expression.

A case of pemphigoid gestationis with concurrent IgG antibodies to BP180, BP230 and type VII collagen

A 22-year-old primigravida had a pruritic, erythematous, bullous eruption on the skin during the 26th week of gestation. After delivery the eruption flared up. The diagnosis of pemphigoid gestationis was confirmed based on histopathological and immunofluorescence findings. The result of immunoblotting showed IgG autoantibodies which reacted against BP230 in epidermal extracts and 290 kDa type VII collagen in dermal extracts. The BP180 antibodies were also detected by an enzyme-linked immunosorbent assay BP180NC16a diagnosis kit. Pulsed corticosteroid and cyclophosphamide resulted in a favourable response at the acute stage. The patient was cured in 2 years. The analysis of the patient's autoantibodies provides strong evidence for the involvement of epitope spreading in her autoimmune disease.

Clinical and immunologic factors associated with bullous pemphigoid relapse during the first year of treatment: a multicenter, prospective study

IMPORTANCE

Although predisposing factors for bullous pemphigoid (BP) have been recently established, no clinical or immunologic factors have yet been identified to predict disease outcome.

OBJECTIVE

To identify risk factors for BP relapse during the first year of treatment.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter prospective study of 120 consecutive patients with newly diagnosed BP in 8 French dermatology departments. Baseline and 6 follow-up visits were planned to record disease activity and collect blood samples for measurement of serum anti-BP180 and anti-BP230 levels by means of enzyme-linked immunosorbent assay (ELISA).

MAIN OUTCOMES AND MEASURES

The end point was clinical relapse within the first year of therapy. Associations of clinical and immunologic (including serum levels of anti-BP180 and anti-BP230 autoantibodies) parameters with clinical relapse were assessed using univariate and multivariate analyses.

RESULTS

During the 1-year follow-up, 35 patients (29.2%) experienced relapse, whereas anti-BP180 and anti-BP230 ELISA results were similar at baseline between patients who did and did not experience relapse. Factors at baseline independently associated with relapse were extensive disease at inclusion (hazard ratio [HR], 2.37 [95% CI, 1.2-4.8]) and an associated dementia (HR, 2.09 [95% CI, 1.0-4.2]). Use of superpotent topical corticosteroids alone (by 100 patients [83.3%]) induced a dramatic, early decrease in serum levels of anti-BP180 and anti-BP230 autoantibodies. Mean early decreases in autoantibody levels between baseline and day 60 were lower in patients with relapse compared with patients with ongoing remission (-10.0% and -45.2%, respectively, for anti-BP180 levels [P < .001] and -11.8% and -35.4%, respectively, for anti-BP230 levels [P = .046]). A higher serum level of anti-BP180 at day 150, with a cutoff of 23 U/mL, provided 84.2% sensitivity, 44.8% specificity, 33.3% positive predictive value, and 89.7% negative predictive value for the occurrence of relapses between days 150 and 360.

CONCLUSIONS AND RELEVANCE

The pronounced decrease in the level of anti-BP180 autoantibodies and, to a lesser extent, those directed against BP230 confirmed the use of superpotent topical corticosteroids alone as a reference BP treatment. Furthermore, our study suggests that neurological diseases play a major role in BP, not only as a predisposing but also as a prognostic factor.

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.

Concomitant bullous pemphigoid and dermatitis herpetiformis

Dermatitis herpetiformis and bullous pemphigoid are bullous autoimmune diseases of the skin microscopically characterized by subepidermal blisters. We present a 77-year-old patient with an 18-month history of disseminated pruritic papular lesions. Direct immunofluorescence microscopy revealed linear deposition of IgG at the basement membrane zone as well as granular deposits of IgA in the papillary dermis. Circulating IgG antibodies against BP180, BP230 and gliadin as well as IgA reactivity against endomysium, tissue transglutaminase, and gliadin were detected compatible with both bullous pemphigoid and dermatitis herpetiformis. Here, we review the English literature on all previously reported patients with co-occurrence of both entities. Interestingly, in previous cases, tissue-bound and serum autoantibodies against the respective target antigens had not yet been completely characterized.

Prevalence and clinical significance of anti-laminin 332 autoantibodies detected by a novel enzyme-linked immunosorbent assay in mucous membrane pemphigoid

IMPORTANCE

A rare variant of mucous membrane pemphigoid (MMP) is characterized by circulating anti-laminin 332 (Lam332) autoantibodies and seems to be associated with concurrent malignant neoplasms.

OBJECTIVE

To determine the prevalence and clinical significance of anti-Lam332 autoantibody detection from a large series of patients with MMP.

DESIGN

Multicenter retrospective study.

SETTING

Four French national centers for autoimmune bullous diseases.

PARTICIPANTS

One hundred fifty-four patients with MMP and 89 individuals serving as controls were included.

INTERVENTIONS

Serum samples were analyzed by a new Lam332 enzyme-linked immunosorbent assay (ELISA); clinical and immunopathologic data were obtained from the patients' medical records.

MAIN OUTCOME MEASURES

The Lam332 ELISA scores were evaluated with respect to clinical characteristics, standard and salt-split indirect immunofluorescence, and bullous pemphigoid (BP) 230 and BP180-NC16A ELISAs.

RESULTS

The Lam332 ELISA score was positive (≥9 U/mL) in 20.1% of serum samples from patients with MMP, 1 of 50 patients with bullous pemphigoid (BP), none of 7 with pemphigus, and 3 of 32 other controls. No relationship was evidenced between a positive ELISA Lam332 score and age; sex ratio; oral, ocular, genital, skin, or esophageal/laryngeal involvement; internal malignant neoplasm; or BP180 ELISA score. Salt-split skin indirect immunofluorescence and ELISA BP230 results were more frequently positive when Lam332 ELISA results were positive (P = .04 and .02, respectively). Patients with a positive Lam332 ELISA score frequently had more severe MMP (67.8% vs 47.2%; P = .04).

CONCLUSIONS AND RELEVANCE

Results of this novel ELISA showed that serum anti-Lam332 autoantibodies are detected in 20.1% of patients with MMP. Anti-Lam332 autoantibodies are mainly detected in patients with severe MMP but not preferentially in those with a malignant neoplasm. The association between anti-Lam332 and anti-BP230 autoantibodies might arise from an epitope-spreading phenomenon.

Association of autoantibodies to BP180 with disease activity in Greek patients with bullous pemphigoid

39 bullous pemphigoid (BP) patients were studied to assess the clinical significance of anti-BP180 and anti-BP230 circulating autoantibodies of BP and correlate their titers with the clinical scores of the BP Disease Area Index (BPDAI) and the Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) as well as with the intensity of pruritus measured by the BPDAI pruritus component. All parameters were evaluated by the time of diagnosis (baseline), month 3, and month 6. Titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (r = 0.557, P value < 0.0001) and ABSIS (r = 0.570, P value < 0.0001) values, as well as with BPDAI component for the intensity of pruritus (rho = 0.530, P value = 0.001) at baseline. At month 3, titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (rho = 0.626, P value = 0.000) and ABSIS (rho = 0.625, P value = 0.000) values, as well as with the BPDAI component for the intensity of pruritus (rho = 0.625, P value = 0.000). At month 6, titers of anti-BP180 autoantibodies were strongly correlated with BPDAI (rho = 0.527, P value = 0.001) and ABSIS (rho = 0.526, P value = 0.001) values, as well as with the BPDAI component for the intensity of pruritus (rho = 0.525, P value = 0.001). There was no statistically significant correlation between titers of anti-BP230 autoantibodies and the BPDAI, ABSIS, and BPDAI component for the intensity of pruritus at the same time points.

Evaluation of the combination of BP180-NC16a enzyme-linked immunosorbent assay and BP230 enzyme-linked immunosorbent assay in the diagnosis of bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is an acquired autoimmune subepidermal blistering disease characterized by circulating IgG autoantibodies directed against BP180 and BP230 hemidesmosomal proteins. Previous studies have demonstrated that antibodies against the NC16a domain of BP180 mediate BP pathogenesis, while antibodies against BP230 enhance the inflammatory response. Recently, commercial BP180-NC16a enzyme-linked immunosorbent assay (ELISA) and BP230 ELISA kits were developed to detect anti-BP180 and anti-BP230 autoantibodies in human BP sera.

AIMS

To evaluate the efficacy of BP180-NC16a ELISA and BP230 ELISA in the initial diagnosis of BP.

METHODS

Sera from 62 BP patients and 62 control subjects were tested by BP180-NC16a ELISA and BP230 ELISA and compared with findings from indirect immunofluorescence (IIF) and immunoblotting (IB) to determine the sensitivity and specificity of these assays.

RESULTS

The sensitivities of BP180-NC16a ELISA and BP230 ELISA were 87.1% (54/62) and 56.5% (35/62), respectively, and the specificities of both were 100% (62/62). Using both ELISAs for diagnosis increased the sensitivity to 95.2% (59/62) and was statistically comparable with IB sensitivity.

CONCLUSIONS

ELISA is a convenient, effective, and reliable method for serodiagnosis of BP, and combined use of BP180-NC16a ELISA and BP230 ELISA can increase the sensitivity of this diagnostic approach.

Anti-skin specific autoantibodies detected by a new immunofluorescence multiplex biochip method in patients with autoimmune bullous diseases

BACKGROUND

Autoimmune blistering skin diseases are a heterogeneous group of diseases characterized by autoantibodies against structural components of the skin. In pemphigus vulgaris (PV) autoantibodies react mainly with desmoglein 3 (Dsg3) alone and/or in combination with desmoglein 1 (Dsg1). In bullous pemphigoid (BP) autoantibodies target two hemidesmosomal proteins, BP180 and BP230.

OBJECTIVE

To evaluate the diagnostic accuracy of a new indirect immunofluorescence (IIF) multiplex biochip method for the detection of anti-skin specific autoantibodies.

METHODS

Sera from 36 patients with PV and from 40 patients with BP were collected. The control group included 54 patients with other skin diseases and 40 healthy subjects. The detection of circulating autoantibodies to Dsg1, Dsg3, BP230 and BP180 was performed with a new IIF multiplex biochip method and with two currently commercially available ELISA methods.

RESULTS

The multiplex IIF method showed a high diagnostic sensitivity (100%) for PV on cells transfected with Dsg3. In patients with BP, the positivity to the BP180 antigen was higher (90%) than that on monkey esophagus (50%) and on cells transfected with BP230 (40%). A good rate of agreement was observed among methods (IIF vs. ELISA) and among ELISA systems.

CONCLUSIONS

The new multiplex biochip IIF method has a high diagnostic accuracy for the diagnosis of PV and BP, comparable to ELISA methods, and is able to screen autoimmune bullous diseases.

Adjuvant treatment of recalcitrant bullous pemphigoid with immunoadsorption

Elimination of pathogenic autoantibodies by immunoadsorption (IA) has been described as an effective adjuvant treatment in severe bullous autoimmune diseases, especially in pemphigus. There is much less experience in the treatment of bullous pemphigoid (BP). BP was diagnosed in a 62-year-old Caucasian woman presenting a pruritic rash with multiple tense blisters. Standard treatments with topical and oral corticosteroids, steroid-sparing agents including dapsone, azathioprine, mycophenolate mofetil (MMF) and intravenous immunoglobulins were ineffective or had to be discontinued due to adverse events. An immediate clinical response could be achieved by two treatment cycles of adjuvant protein A immunoadsorption (PA-IA) in addition to continued treatment with MMF (2 g/day) and prednisolone (1 mg/kg/day). Tolerance was excellent. Clinical improvement remained stable after discontinuation of IA and went along with sustained reduction of circulating autoantibodies. Our data demonstrate that PA-IA might be a safe and effective adjuvant treatment in severe and recalcitrant BP.

IgE recognition of bullous pemphigoid (BP)180 and BP230 in BP patients and elderly individuals with pruritic dermatoses

Bullous pemphigoid (BP) is the most common autoimmune bullous disease of the elderly and is associated with IgG and IgE autoantibodies against the hemidesmosomal proteins, BP180 and BP230. The purpose of this study was to characterize the epitope specificity of IgE against defined regions of BP180 and BP230 in 32 BP patients and 21 elderly patients with pruritic disorders who did not yet fulfill all the criteria of BP by immunoblot (IB), ELISA and indirect immunofluorescence microscopy. Our findings show that IgE from BP sera preferentially targets the COOH-terminus of BP230 (IB: 16/32, ELISA: 12/32) and, to a lesser extent, the BP180-NC16A domain (IB: 11/32, ELISA: 9/32). Noteworthy, a subgroup of elderly patients with pruritic dermatoses also showed IgE recognition of BP180-NC16A (IB: 1/21, ELISA: 4/21) and less frequently of BP230 (IB: 2/21, ELISA: 2/21). Thus, IgE recognition of the BP autoantigens is presumably an early pathogenetic event in BP.

The molecular basis for the presence of two autoimmune diseases occurring simultaneously--preliminary observations based on computer analysis

Specific Human Leukocyte Antigen Class II (HLA II) molecules associated with pemphigus vulgaris (PV), mucous membraine pemphigoid (MMP), and mixed connective tissue disease (MCTD) may react with multiple T cell epitopes within desmoglein 3 (Dsg 3), bullous pemphigoid antigen 2 (BPAG 2), and 70 kDa polypeptide small nuclear ribonucleoproteins (snRNP70) in autoantibody production. We report a group of patients with simultaneous occurrences of PV with MCTD, and MMP with MCTD. In one patient group, we performed serological studies to show presence of antibodies to Dsg 3, Dsg 1, and snRNP70 simultaneously. In the second group, we performed serological studies to show presence of antibodies to BPAG 1, BPAG 2, β4 integrin, and snRNP70 simultaneously. In both groups, HLA II genes were analyzed and the observations were consistent with previously described associations with PV, MMP, and MCTD. It is possible that HLA-DQβ1*0301 allele, present in 10 of 17 patients and DRβ1*04 in some of the others, may have the ability to bind to several relevant T cell epitopes in the snRNP70 molecule. We have utilized a computer model to demonstrate that HLA II-restricted T cell epitopes present within the known autoantigens may be capable of eliciting an immune response. While other explanations and mechanisms exist, the authors suggest that epitope spreading may be one possible mechanism, amongst others, that may result in the simultaneous presence of two separate pathogenic autoantibodies.

Neuronal dystonin isoform 2 is a mediator of endoplasmic reticulum structure and function

Dystonin/Bpag1 is a cytoskeletal linker protein whose loss of function in dystonia musculorum (dt) mice results in hereditary sensory neuropathy. Although loss of expression of neuronal dystonin isoforms (dystonin-a1/dystonin-a2) is sufficient to cause dt pathogenesis, the diverging function of each isoform and what pathological mechanisms are activated upon their loss remains unclear. Here we show that dt(27) mice manifest ultrastructural defects at the endoplasmic reticulum (ER) in sensory neurons corresponding to in vivo induction of ER stress proteins. ER stress subsequently leads to sensory neurodegeneration through induction of a proapoptotic caspase cascade. dt sensory neurons display neurodegenerative pathologies, including Ca(2+) dyshomeostasis, unfolded protein response (UPR) induction, caspase activation, and apoptosis. Isoform-specific loss-of-function analysis attributes these neurodegenerative pathologies to specific loss of dystonin-a2. Inhibition of either UPR or caspase signaling promotes the viability of cells deficient in dystonin. This study provides insight into the mechanism of dt neuropathology and proposes a role for dystonin-a2 as a mediator of normal ER structure and function.

Bullous pemphigoid: from the clinic to the bench

Bullous pemphigoid (BP) constitutes the most frequent autoimmune subepidermal blistering disease. It is associated with autoantibodies directed against the BP antigens 180 (BP180, BPAG2) and BP230 (BPAG1-e). The pathogenicity of anti-BP180 antibodies has been convincingly demonstrated in animal models. The clinical features of BP are extremely polymorphous. The diagnosis of BP critically relies on immunopathologic findings. The recent development of novel enzyme-linked immunosorbent assays has allowed the detection of circulating autoantibodies with relatively high sensitivity and specificity. Although potent topical steroids have emerged in the past decade as first-line treatment of BP, management of the disease may be challenging.

Demonstration of epitope-spreading phenomena in bullous pemphigoid: results of a prospective multicenter study

Bullous pemphigoid (BP), the most common autoimmune subepidermal bullous disease, is associated with an autoantibody response to BP180 and BP230, two components of junctional adhesion complexes in human skin promoting dermo-epidermal cohesion. Retrospective analyses demonstrated that these autoantigens harbor several epitopes targeted by autoaggressive B and T cells. The aim of this prospective multicenter study was to assess the evolution of IgG autoantibodies in 35 BP patients over a 12-month observation period. Epitope-spreading (ES) events were detected in 17 of 35 BP patients (49%). They preferentially occurred in an early stage of the disease and were significantly related to disease severity at diagnosis. Moreover, in three patients, spreading of IgG reactivity to intracellular epitopes of BP180 and BP230 was preceded by recognition of the BP180 ectodomain. Finally, IgG reactivity with extracellular epitopes of BP180 and intracellular epitopes of BP230 correlated with the severity of BP in disease course. These findings support the idea that IgG recognition of the BP180 ectodomain is an early and crucial event in BP disease, followed by variable intra- and intermolecular ES events, which likely shape the individual course of BP.

Role of MHC Class II genes in the pathogenesis of pemphigoid

Pemphigoid (Pg) is an autoimmune subepidermal blistering disease that affects the elderly population. The phenotype can be Bullous Pemphigoid (BP), which primarily involves the skin, or Mucous Membrane Pemphigoid (MMP), which primarily involves mucus membranes. Ocular Cicatricial Pemphigoid (OCP) and Oral Pemphigoid (OP) are subsets of MMP. The known antigens in BP are Bullous Pemphigoid Antigen 1 (BPAG1, also known as BP230), Bullous Pemphigoid Antigen 2 (BPAG2, also known as BP180), and subunits of human integrins α6 and β4. The Human Leukocyte Antigen (HLA) allele HLA-DQβ1*0301 has been reported to be associated with enhanced susceptibility to all of these subsets. Sera of patients with the four subsets are characterized by the presence of anti-Basement Membrane Zone (anti-BMZ) antibodies. In this manuscript, we present a model in which relevant portions of the four different antigens involved in pemphigoid have potential sites that could be presented by an antigen presenting cell (APC) in conjunction with DQβ1*0301 to a T cell receptor to initiate the process that results in anti-BMZ antibody production. Thus, this model provides a hypothetical computer-based mechanism to explain how a single HLA allele can be associated with the production of antibodies to four different antigens that result in four different subsets of a disease with four different clinical profiles and prognoses.

Molecular organization of the basement membrane zone

The dermal-epidermal basement membrane is a complex assembly of proteins that provide adhesion and regulate many important processes such as development, wound healing, and cancer progression. This contribution focuses on the structure and function of individual components of the basement membrane, how they assemble together, and how they participate in human tissues and diseases, with an emphasis on skin involvement. Understanding the composition and structure of the basement membrane provides insight into the pathophysiology of inherited blistering disorders, such as epidermolysis bullosa, and acquired bullous diseases, such as the pemphigoid group of autoimmune diseases and epidermolysis bullosa acquisita.

Activation of coagulation in bullous pemphigoid and other eosinophil-related inflammatory skin diseases

Bullous pemphigoid (BP) is a skin disease caused by autoantibodies to hemidesmosomal proteins BP180 and BP230, with eosinophils participating in blister formation. Tissue factor (TF), the initiator of coagulation, is embodied within the eosinophil granules and exposed upon activation. We evaluated the coagulation activation in patients with BP (63), chronic urticaria (CU; 20), atopic dermatitis (AD; 14), cutaneous drug reactions (CDRs; six), psoriasis (20), dermatitis herpetiformis (DH; four) and primary cutaneous T cell lymphoma (CTCL; five), and in 40 healthy controls. Prothrombin fragment F1+2 and d-dimer (coagulation markers) were measured by enzyme-linked immunosorbent assay (ELISA) in all plasma samples and BP blister fluid. Skin TF expression was evaluated immunohistochemically in the patients and 20 controls. F1+2 and d-dimer levels were higher in BP plasma than in control plasma (P = 0·0001 for both), and dramatically high in blister fluid; both correlated positively with disease severity, esinophil counts and anti-BP180 antibodies (P = 0·006-0·0001). Plasma F1+2 and d-dimer levels were higher in the CU, AD and CDR patients than in controls (P = 0·0001 for all), but normal in the psoriasis, DH and CTCL patients. Skin TF was expressed in the BP (P = 0·0001), CU (P = 0·0001), AD (P = 0·001) and CDR patients (P = 0·01), but not in the psoriasis, DH or CTCL patients. Co-localization confocal microscopy studies confirmed eosinophils as the source of TF in 10 BP patients. The coagulation cascade is activated in BP and other eosinophil-mediated skin disorders, but not in non-eosinophil driven conditions. This hypercoagulability may contribute to inflammation, tissue damage and, possibly, thrombotic risk.

Motor unit abnormalities in Dystonia musculorum mice

Dystonia musculorum (dt) is a mouse inherited sensory neuropathy caused by mutations in the dystonin gene. While the primary pathology lies in the sensory neurons of dt mice, the overt movement disorder suggests motor neurons may also be affected. Here, we report on the contribution of motor neurons to the pathology in dt(27J) mice. Phenotypic dt(27J) mice display reduced alpha motor neuron cell number and eccentric alpha motor nuclei in the ventral horn of the lumbar L1 spinal cord region. A dramatic reduction in the total number of motor axons in the ventral root of postnatal day 15 dt(27J) mice was also evident. Moreover, analysis of the trigeminal nerve of the brainstem showed a 2.4 fold increase in number of degenerating neurons coupled with a decrease in motor neuron number relative to wild type. Aberrant phosphorylation of neurofilaments in the perikaryon region and axonal swellings within the pre-synaptic terminal region of motor neurons were observed. Furthermore, neuromuscular junction staining of dt(27J) mouse extensor digitorum longus and tibialis anterior muscle fibers showed immature endplates and a significant decrease in axon branching compared to wild type littermates. Muscle atrophy was also observed in dt(27J) muscle. Ultrastructure analysis revealed amyelinated motor axons in the ventral root of the spinal nerve, suggesting a possible defect in Schwann cells. Finally, behavioral analysis identified defective motor function in dt(27J) mice. This study reveals neuromuscular defects that likely contribute to the dt(27J) pathology and identifies a critical role for dystonin outside of sensory neurons.

Alterations in type I hemidesmosome components suggestive of epigenetic control in the salivary glands of patients with Sjögren's syndrome

Objective

Acinar cells in the salivary glands of patients with Sjögren's syndrome (SS) display severe alterations in anchorage to the basal lamina. Bioinformatics analysis of the BP230 gene sequence has revealed the presence of CpG islands that might be involved in epigenetic control of gene expression, and methylation of the BP230 promotor region may be implicated as an epigenetic control mechanism in salivary gland damage. Thus, the present study was undertaken to evaluate the protein BP230, as well as proteins BP180, α6β4 integrin, and cytokeratin‐18, for their expression levels, localization, and ability to form hemidesmosome adhesion complexes.

Methods

Eighteen patients with primary SS and 14 healthy control subjects were studied. Levels of messenger RNA (mRNA) and protein were measured by reverse transcription–polymerase chain reaction and Western blotting, respectively. BP230 methylation was determined by methylation‐sensitive polymerase chain reaction. Protein complexes were analyzed by immunoprecipitation and assessed for localization by immunofluorescence.

Results

In patients with SS as compared with controls, BP230 mRNA levels were decreased while protein levels were increased, and the gene promotor region was hypermethylated. Augmented proteolysis of BP180 was detected, since levels of linear IgA disease fragment 1 were increased. The complex‐forming ability of BP230, BP180, α6β4 integrin, and cytokeratin‐18 was maintained in patients with SS, in contrast to that in controls. BP230 and BP180 colocalized at the basal membrane of acinar cells, and cleavage of BP180 coincided with a loss of colocalization.

Conclusion

The decrease in BP230 mRNA levels may be explained by gene hypermethylation. We postulate that local epigenetic modifications of BP230 are produced in response to factors present in the damaged salivary glands of patients with SS. Additionally, the paradoxical increase in BP230 protein levels and the formation of both normal and altered adhesion complexes may help avoid cell death induced by the loss of anchorage.