Serum reactivity in dermatitis herpetiformis: an international multicentre study.

BACKGROUND: Dermatitis herpetiformis (DH) is a rare gluten-induced skin disorder characterized predominantly by IgA autoantibodies against endomysium, tissue transglutaminase (TG2/tTG), epidermal transglutaminase (TG3/eTG) and deamidated gliadin. To date, circulating autoantibody reactivity has not been systematically described. OBJECTIVES: Characterization of serum reactivities in DH. METHODS: This multicentre international study analysed sera from 242 patients with DH taken at the time of initial diagnosis. DH-specific IgA and IgG serum autoantibodies were analysed by indirect immunofluorescence (IF) on monkey oesophagus, and by enzyme-linked immunosorbent assay (ELISA) based on recombinant TG2/tTG, TG3/eTG and deamidated gliadin (GAF3X). RESULTS: IgA indirect IF microscopy on monkey oesophagus revealed the highest reactivity (84.3%; specificity 100%) followed by IgA TG2/tTG ELISA (78.5%, specificity 99.0%), IgA TG3/eTG ELISA (72.7%, specificity 95.0%) and IgA GAF3X ELISA (69.0%, specificity 98.5%). CONCLUSIONS: Serum IgA and IgG autoantibodies against endomysium, TG2/tTG, TG3/eTG and deamidated gliadin are highly prevalent in DH. Indirect IF microscopy on monkey oesophagus (IgA) provides the highest diagnostic accuracy that can be further enhanced by 4.5% when combined with IgA TG2/tTG ELISA.

Skin-Related Quality of Life During Autoimmune Bullous Disease Course.

Importance: Autoimmune bullous diseases (AIBDs) are chronic relapsing-remitting conditions with significant morbidity. Skin-related quality of life (SRQL) may vary by AIBD subtype and disease type. Disease severity and flare severity can be difficult to define; SRQL can offer a key insight. Objectives: To investigate the Skindex-16 score as an SRQL measure in AIBD subtypes during flare and nonflare states and to evaluate Skindex-16 construct validity. Design, Setting, and Participants: This retrospective cross-sectional study was conducted from September 1, 2016, to February 1, 2020, among 192 patients at the University of Utah Health autoimmune dermatology clinic with pemphigoid, pemphigus, dermatitis herpetiformis, and linear immunoglobulin A disease. Patients had an encounter-associated diagnosis, Skindex-16 scores, and self-reported flare status. Statistical analysis was performed from March 2022 to June 2023. Exposure: Autoimmune bullous disease subtype and patient-reported flare status. Main Outcomes and Measures: Skindex-16 domain scores (emotions, symptoms, and functioning; range, 0-100, where 0 indicates no effect on SRQL and 100 maximum effect) and individual item scores were described by disease and flare status. Flare scores were expected to be higher by at least the standard error of measurement (SEm). Convergent validity was assessed using Spearman correlation among Skindex-16 scores, serologic titers, and other patient-reported outcome measures. Floor or ceiling domain scores (<20% of sample scoring either lowest or highest possible domain scores, respectively) were assessed for Skindex-16. Structural validity was assessed using confirmatory factor analysis (CFA). Results: The study included 192 patients with 212 visits (median age, 68 years [IQR, 58-76 years]; 123 of 212 women [58.0%]) with Skindex-16 scores (64 in flare state and 148 in nonflare state). Median Skindex-16 domain scores were higher for all disease categories among patients in the flare state compared with those in the nonflare state (pemphigoid [emotions: flare, 52.4 (IQR, 38.1-69.0); nonflare, 7 (IQR, 0-17); symptoms: flare, 37.5 (IQR, 29.2-58.0); nonflare, 13 (IQR, 0-25); functioning: flare, 26.7 (IQR, 10.0-56.7); nonflare, 0 (IQR, 0-3)]; pemphigus [emotions: flare, 54.8 (IQR, 31.0-81.0; nonflare, 0 (IQR, 0-19); symptoms: flare, 58.3 (IQR, 41.7-70.8); nonflare, 4 (IQR, 0-12.5); functioning: flare, 26.7 (IQR, 13.3-83.3); nonflare, 0 (IQR, 0-3.33)]; dermatitis herpetiformis [emotions: flare, 72.6 (IQR, 34.7-90.5); nonflare, 14.3 (IQR, 2.4-26.2); symptoms: flare, 69 (IQR, 31.3-85.4); nonflare, 12.5 (IQR, 0-29.2); functioning: flare, 38.3 (IQR, 5.0-63.2); nonflare, 0 (IQR, 0-13.3)]. This difference exceeded SEm cut points. Cronbach α was greater than 0.80 for all domains and AIBDs. Moderate or low correlations were seen with desmoglein 1 and bullous pemphigoid 180 titers. Moderate correlation existed between Skindex-16 and Patient-Reported Outcomes Measurement Information System Depression scores (emotions: ρ = 0.40; symptoms: ρ = 0.41; functioning: ρ = 0.48), and strong correlation existed between Skindex-16 and patient-reported disease severity (emotions: ρ = 0.71; symptoms: ρ = 0.73; functioning: ρ = 0.66). Floor domain scores greater than 20% were seen among patients in the nonflare state, but ceiling domain scores were rare (<10% for all domains); CFA model fit was poor. Conclusions and Relevance: In this cross-sectional study, SRQL was highly associated with flare of AIBDs. Skin-related quality of life was worse during periods without flare among patients with pemphigoid and dermatitis herpetiformis compared with pemphigus, highlighting residual SRQL morbidity. Skindex-16 showed good construct validity, but the poor CFA model fit needs further research. Clinical measurement of SRQL in AIBDs can add critical disease-severity information.

Diagnostics for Dermatologic Diseases with Autoantibodies.

BACKGROUND: Dermatologic diseases with autoantibodies were recognized early as autoimmunity became accepted as a pathogenic immunologic concept. Laboratory testing to identify disease-defining autoantibodies and investigate their role in pathophysiology has evolved since. CONTENT: Blistering dermatologic diseases, profiled by autoantibody production, target epithelial components critical in cell-cell and cell-matrix adhesion, resulting in epithelial separation and other characteristic features of the disorders. This review covers the clinical indications for dermatologic disease-related autoantibody testing, the specifics of procuring specimens to test, the available diagnostic tests, and information provided by the testing. Atypical, uncharacteristic, and less well-known clinical and autoantibody profiles as well as several of the many future prospects for expansion of the testing applications are elaborated on in the online Data Supplement. SUMMARY: Autoantibody-associated dermatologic diseases are acquired immunologic disorders that have considerable clinical implications affecting essential barrier functions of skin and mucous membranes and causing discomfort, including pain and pruritus. Certain of the diseases can have life-threatening manifestations, and treatments can have significant side-effects. The skin diseases may presage other clinical associations that are important to recognize and treat. Laboratory testing aids in the diagnosis of these diseases through identification of the autoantibodies and is essential for prompt and precise knowledge of the disease type for prognosis, further clinical evaluations, and treatment decisions.

Diagnosis and management of pemphigus: Recommendations of an international panel of experts.

BACKGROUND: Several European countries recently developed international diagnostic and management guidelines for pemphigus, which have been instrumental in the standardization of pemphigus management. OBJECTIVE: We now present results from a subsequent Delphi consensus to broaden the generalizability of the recommendations. METHODS: A preliminary survey, based on the European Dermatology Forum and the European Academy of Dermatology and Venereology guidelines, was sent to a panel of international experts to determine the level of consensus. The results were discussed at the International Bullous Diseases Consensus Group in March 2016 during the annual American Academy of Dermatology conference. Following the meeting, a second survey was sent to more experts to achieve greater international consensus. RESULTS: The 39 experts participated in the first round of the Delphi survey, and 54 experts from 21 countries completed the second round. The number of statements in the survey was reduced from 175 topics in Delphi I to 24 topics in Delphi II on the basis of Delphi results and meeting discussion. LIMITATIONS: Each recommendation represents the majority opinion and therefore may not reflect all possible treatment options available. CONCLUSIONS: We present here the recommendations resulting from this Delphi process. This international consensus includes intravenous CD20 inhibitors as a first-line therapy option for moderate-to-severe pemphigus.

A Nonsynonymous Variant in the GOLM1 Gene in Cutaneous Malignant Melanoma.

Background: Statistically significant linkage of melanoma to chromosome 9q21 was previously reported in a Danish pedigree resource and independently confirmed in Utah high-risk pedigrees, indicating strong evidence that this region contains a melanoma predisposition gene. Methods: Whole-exome sequencing of pairs of related melanoma case subjects from two pedigrees with evidence of 9q21 linkage was performed to identify the responsible predisposition gene. Candidate variants were tested for association with melanoma in an independent set of 454 unrelated familial melanoma case subjects and 396 unrelated cancer-free control subjects from Utah, and 1534 melanoma case subjects and 1146 noncancer control subjects from Texas (MD Anderson) via a two-sided Fisher exact test. Results: A rare nonsynonymous variant in Golgi Membrane Protein 1 (GOLM1), rs149739829, shared in two hypothesized predisposition carriers in one linked pedigree was observed. Segregation of this variant in additional affected relatives of the index carriers was confirmed. A statistically significant excess of carriers of the variant was observed among Utah case subjects and control subjects (odds ratio [OR] = 9.81, 95% confidence interval [CI] = 8.35 to 11.26, P < .001) and statistically significantly confirmed in Texas case subjects and control subjects (OR = 2.45, 95% CI = 1.65 to 3.25, P = .02). Conclusion: These findings support GOLM1 as a candidate melanoma predisposition gene.

A subset of patients with pemphigoid (herpes) gestationis has serological evidence of celiac disease.

BACKGROUND: Pemphigoid (herpes) gestationis (PG) is an uncommon, self-limited disease with other autoimmune associations; however, celiac disease (CD) is not recognized as one. METHODS: From 71 patients' sera submitted for herpes gestationis factor (HGF) testing over a 5-year period, 12 were consistent with PG demonstrating HGF and increased IgG BP180 antibody levels; these sera were tested for IgA and IgG endomysial antibodies (EMA), epithelial basement membrane zone and cell surface antibodies by indirect immunofluorescence, and for IgA and IgG tissue transglutaminase (transglutaminase 2 or TG2) antibodies, IgA epidermal transglutaminase (transglutaminase 3 or TG3) antibodies, IgG BP230, and IgG desmoglein 1 and desmoglein 3 antibodies by enzyme-linked immunosorbent assays (ELISAs). RESULTS: Three of 12 patients' sera with PG (25%) had CD antibodies with positive IgA EMA and increased IgA TG2 antibody levels; two of these had positive IgG EMA, and one other had an increased IgA TG3 antibody level. CONCLUSIONS: A subset of patients with serological findings of PG also has serological evidence of CD, which may have implications in the etiopathogenesis of PG and which reveals important information about the mother's, and possibly her infant's, health.

Pathophysiology of Autoimmune Bullous Diseases: Nature Versus Nurture.

Pemphigus and pemphigoid are the prototypical immunobullous diseases. Although it has been well established that they are caused by deposition of autoreactive antibodies directed against adherence proteins within the skin, the specific genetic and environmental factors leading to development of these diseases continue to be an area of investigation. Herein, we discuss several of the potential environmental triggers that may induce patients to develop immunobullous diseases including medications, viral infections, UV exposure or other radiation injury and dietary factors. In addition, the potential genetic and immunologic mechanisms contributing to the pathogenesis of pemphigus and pemphigoid will be reviewed. The multifactorial nature of these diseases contributes to their complexity and highlights the importance of a detailed personal and family history when caring for these patients.

Rituximab Treatment for Recalcitrant Dermatitis Herpetiformis.

Importance: Dermatitis herpetiformis (DH) is an autoimmune blistering condition seen in the context of celiac disease. While typically managed by gluten-free diet and dapsone, treatment of DH refractory to standard treatments is not well defined. Observations: A man in his 80s with DH not controlled by gluten-free diet (with poor adherence), dapsone, and conventional immune-suppressing agents responded to treatment with rituximab according to the lymphoma protocol (4 weekly infusions of 375 mg/m2). Thirteen months after treatment, the patient had achieved complete resolution of pruritus and clinical manifestations of the disease, as well as normalization of antibodies against epidermal and tissue transglutaminases. He achieved complete clinical and serological remission and has remained symptom-free up to 18 months following treatment. Conclusions and Relevance: We present here the first case of a patient with DH treated with rituximab who achieved complete clinical and serological remission. We suggest rituximab as a viable treatment option for recalcitrant DH.

Granular C3 Dermatosis.

There has been no previous systematic study of bullous skin diseases with granular basement membrane zone deposition exclusively of C3. In this study we collected 20 such patients, none of whom showed cutaneous vasculitis histopathologically. Oral dapsone and topical steroids were effective. Various serological tests detected no autoantibodies or autoantigens. Direct immunofluorescence for various complement components revealed deposition only of C3 and C5-C9, indicating that no known complement pathways were involved. Studies of in situ hybridization and micro-dissection with quantitative RT-PCR revealed a slight reduction in expression of C3 in patient epidermis. These patients may represent a new disease entity, for which we propose the term "granular C3 dermatosis". The mechanism for granular C3 deposition in these patients is unknown, but it is possible that the condition is caused by autoantibodies to skin or aberrant C3 expression in epidermal keratinocytes.

Persistence of Autoreactive IgA-Secreting B Cells Despite Multiple Immunosuppressive Medications Including Rituximab.

IMPORTANCE: Immunobullous diseases mediated by IgA are often difficult to manage, but to date no mechanism has been proposed. Rituximab is an anti-CD20 monoclonal antibody that has demonstrated good efficacy in the treatment of refractory mucous membrane pemphigoid. However, not all cases of mucous membrane pemphigoid respond to rituximab. Herein we present a case of treatment-refractory mucous membrane pemphigoid and propose a mechanism to explain the lack of response to therapy. OBSERVATIONS: Before treatment, direct immunofluorescent examination of a biopsy sample from the patient's perilesional skin demonstrated linear deposition of IgG and IgA along the dermoepidermal junction. After a multidrug immunosuppressive regimen that included rituximab, results of a second biopsy demonstrated only IgA along the dermoepidermal junction. This finding correlated well with flow cytometry data from the same patient that demonstrated a persistent population of IgA-secreting plasmablasts/plasma cells, despite depletion of CD20⁺ cells. In addition, results of immunohistochemical analysis of the perilesional skin remained positive for CD19 and CD138 immune cells (plasmablast/plasma cell markers). CONCLUSIONS AND RELEVANCE: These findings suggest that current available immunosuppressive medications, including rituximab, cannot eliminate IgA-secreting plasmablasts/plasma cells, which are likely central to the pathophysiology of IgA-mediated immunobullous diseases. Future studies are needed to develop alternative therapeutic strategies that target autoreactive IgA-secreting plasmablasts/plasma cells.

Specific nongluten proteins of wheat are novel target antigens in celiac disease humoral response.

While the antigenic specificity and pathogenic relevance of immunologic reactivity to gluten in celiac disease have been extensively researched, the immune response to nongluten proteins of wheat has not been characterized. We aimed to investigate the level and molecular specificity of antibody response to wheat nongluten proteins in celiac disease. Serum samples from patients and controls were screened for IgG and IgA antibody reactivity to a nongluten protein extract from the wheat cultivar Triticum aestivum Butte 86. Antibodies were further analyzed for reactivity to specific nongluten proteins by two-dimensional gel electrophoresis and immunoblotting. Immunoreactive molecules were identified by tandem mass spectrometry. Compared with healthy controls, patients exhibited significantly higher levels of antibody reactivity to nongluten proteins. The main immunoreactive nongluten antibody target proteins were identified as serpins, purinins, α-amylase/protease inhibitors, globulins, and farinins. Assessment of reactivity toward purified recombinant proteins further confirmed the presence of antibody response to specific antigens. The results demonstrate that, in addition to the well-recognized immune reaction to gluten, celiac disease is associated with a robust humoral response directed at a specific subset of the nongluten proteins of wheat.

Pemphigus vulgaris autoantibody profiling by proteomic technique.

Pemphigus vulgaris (PV) is a mucocutaneous blistering disease characterized by IgG autoantibodies against the stratified squamous epithelium. Current understanding of PV pathophysiology does not explain the mechanism of acantholysis in patients lacking desmoglein antibodies, which justifies a search for novel targets of pemphigus autoimmunity. We tested 264 pemphigus and 138 normal control sera on the multiplexed protein array platform containing 701 human genes encompassing many known keratinocyte cell-surface molecules and members of protein families targeted by organ-non-specific PV antibodies. The top 10 antigens recognized by the majority of test patients' sera were proteins encoded by the DSC1, DSC3, ATP2C1, PKP3, CHRM3, COL21A1, ANXA8L1, CD88 and CHRNE genes. The most common combinations of target antigens included at least one of the adhesion molecules DSC1, DSC3 or PKP3 and/or the acetylcholine receptor CHRM3 or CHRNE with or without the MHC class II antigen DRA. To identify the PV antibodies most specific to the disease process, we sorted the data based on the ratio of patient to control frequencies of antigen recognition. The frequency of antigen recognition by patients that exceeded that of control by 10 and more times were the molecules encoded by the CD33, GP1BA, CHRND, SLC36A4, CD1B, CD32, CDH8, CDH9, PMP22 and HLA-E genes as well as mitochondrial proteins encoded by the NDUFS1, CYB5B, SOD2, PDHA1 and FH genes. The highest specificity to PV showed combinations of autoantibodies to the calcium pump encoded by ATP2C1 with C5a receptor plus DSC1 or DSC3 or HLA-DRA. The results identified new targets of pemphigus autoimmunity. Novel autoantibody signatures may help explain individual variations in disease severity and treatment response, and serve as sensitive and specific biomarkers for new diagnostic assays in PV patients.

Linkage analysis of extended high-risk pedigrees replicates a cutaneous malignant melanoma predisposition locus on chromosome 9q21.

Three predisposition genes have been identified for cutaneous malignant melanoma (CMM), but they account for only ∼25% of melanoma clusters/pedigrees. Linkage analyses of melanoma pedigrees from many countries have failed to identify significant linkage evidence for the remaining predisposition genes that must exist. The Utah linkage analysis approach of using singly informative extended high-risk pedigrees combined with high-density single-nucleotide polymorphism (SNP) markers has successfully identified significant linkage evidence for two regions. This is, to our knowledge, the first genome-wide linkage analysis of the extended Utah high-risk CMM pedigrees, and it provides confirmation of linkage for a chromosome 9q region previously reported in Danish pedigrees. This report confirms that linkage analysis for common disorders can be successful in analysis of high-density markers in sets of singly informative high-risk pedigrees.

Two Japanese cases of dermatitis herpetiformis associated each with lung cancer and autoimmune pancreatitis but showing no intestinal symptom or circulating immunoglobulin A antibodies to any known antigens.

Dermatitis herpetiformis (DH) is common in some Caucasian populations but extremely rare in Japanese, probably because of different immunogenetic backgrounds. We report two Japanese DH cases with typical clinical, histological and direct immunofluorescence features. However, no symptom of gluten-sensitive enteropathy was shown. The diagnosis was confirmed by eliminating other autoimmune blistering diseases by indirect immunofluorescence, enzyme-linked immunosorbent assays and immunoblotting. However, circulating immunoglobulin (Ig)A anti-endomysium, reticulin and gliadin antibodies were not detected. IgA antibodies to tissue and epidermal transglutaminases were also negative. One case was associated with lung cancer and the other one with autoimmune pancreatitis. On review of 17 cases of DH reported in Japan over the previous 10 years, including our cases, one case was associated with gluten-sensitive enteropathy, four with malignant neoplasms, two with autoimmune systemic disorders and one with psoriasis. Although our cases were typical of DH in clinical, histopathological and IgA deposit features, they showed different human leukocyte antigen haplotypes, no gluten-sensitive enteropathy and no DH-specific IgA antibodies, including those to epidermal and tissue transglutaminases. These results suggest that studies of unique characteristics in Japanese DH patients should facilitate further understanding of pathogenesis in DH.