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Importance: Ecthyma contagiosum, or orf, is a viral zoonotic infection caused by Poxviridae. Although human orf infection is considered to follow a self-limited course, various immunological reactions may be triggered, including immunobullous diseases. In the majority of the latter cases, the antigenic target remained enigmatic., Objective: To characterize the predominant autoantigen in orf-induced immunobullous disease and further describe this clinical entity., Design, Setting, and Participants: This multicenter case series sought to provide detailed clinical, histopathological and immunological characteristics of a patient with orf-induced pemphigoid. Based on this index patient, serological analyses were conducted of 4 additional patients with previously reported orf-induced immunobullous disease. Immunoblotting with extracellular matrix and a recently established indirect immunofluorescence assay for detection of serum anti-laminin 332 IgG were performed., Exposures: The disease course and clinical characteristics of orf-induced immunobullous disease were observed., Main Outcomes and Measures: Orf-induced immunobullous disease is primarily characterized by anti-laminin 332 autoantibodies, predominant skin involvement, and a self-limiting course. The study provides further details on epidemiological, clinical, immunopathological, diagnostic, and therapeutic aspects of orf-induced immunobullous disease., Results: In all 5 patients, IgG1 and/or IgG3 autoantibodies against laminin 332 were identified. The α3, β3, and γ2 chains were recognized in 2, 4, and 1 patient(s), respectively., Conclusions and Relevance: In this case series, laminin 332, a well-known target antigen in mucous membrane pemphigoid, was a major autoantigen in orf-induced immunobullous disease, even though predominant mucosal lesions were lacking in this autoimmune blistering disease. Orf-induced anti-laminin 332 pemphigoid is proposed as distinct clinical entity.

Physician‒scientists have made countless discoveries, and their dwindling numbers are a significant concern. Although dermatology has become an increasingly popular destination for physician‒scientist trainees, the proportion of trainees who pursue scientific research careers after training is among the lowest of all medical specialties. To investigate this problem, we surveyed a national cohort of dermatology educators, physician‒scientist track program directors, and National Institute of Arthritis and Musculoskeletal and Skin Diseases T32 directors for opinions regarding physician‒scientist training in dermatology. On the basis of these findings and to help address the issue, we propose a training practicum and provide a resource for funding opportunities to help guide trainees and institutions interested in supporting investigative dermatologists. We also discuss the important roles of department chairs and institutions in fashioning an environment conducive to physician‒scientist training. The information and recommendations provided in this paper may help to improve the recruitment, training, development, and retention of investigative dermatologists and future leaders in this field., (© 2021 The Authors.)

Background: The Dermatology Foundation (DF) has a comprehensive career development award (CDA) program., Objective: To assess the impact of this program, a cross-sectional survey of recipients receiving support between 1990 and 2012 was performed., Methods: Award recipients completed a questionnaire concerning their career status and record of research funding. To verify the self-reported funding data, information about each awardee was extracted from the National Institutes of Health Research Portfolio Online Reporting Tools database and used to define funding acquired by CDA recipients., Results: In all, 84% of CDA recipients responded to the survey. A total of 213 awardees (79%) hold full- or part-time positions in academic medicine. Approximately 70% of the award recipients in academic medicine have received federal research funding. The National Institutes of Health Research Portfolio Online Reporting Tools database and other sources indicated that the funding acquired by CDA recipients through 2015 and 2017 amounted to approximately $365.4 million and $451.8 million, respectively. Each dollar of DF CDA funding through 2015 (ie, $36.2 million) was linked to more than $10 in grant support through 2015 and $12 through 2017., Limitations: This cross-sectional survey was retrospective and (in part) self-reported., Conclusions: The DF has succeeded in supporting the career development of basic, translational, and clinical investigators and fostered the promotion and retention of these individuals in academic medicine., (Copyright © 2018 American Academy of Dermatology, Inc. All rights reserved.)

Background: Antilaminin 332 mucous membrane pemphigoid (MMP) is an autoimmune subepidermal blistering disease with predominant mucosal involvement and autoantibodies against laminin 332. Malignancies have been associated with this disease; however, no standardized detection system for antilaminin 332 serum antibodies is widely available., Objectives: Development of a sensitive and specific assay for the detection of antilaminin 332 antibodies., Methods: An indirect immunofluorescence (IF) assay using recombinant laminin 332 was developed and probed with a large number of antilaminin 332 MMP patient sera (n = 93), as well as sera from patients with antilaminin 332-negative MMP (n = 153), bullous pemphigoid (n = 20), pemphigus vulgaris (n = 20) and noninflammatory dermatoses (n = 22), and healthy blood donors (n = 100)., Results: In the novel IF assay, sensitivities with the laminin 332 heterotrimer and the individual α3, β3 and γ2 chains were 77%, 43%, 41% and 13%, respectively, with specificities of 100% for each substrate. The sensitivity for the heterotrimer increased when an anti-IgG4 enriched antitotal IgG conjugate was applied. Antilaminin 332 reactivity paralleled disease activity and was associated with malignancies in 25% of patients with antilaminin 332 MMP., Conclusions: The novel IF-based assay will facilitate the serological diagnosis of antilaminin 332 MMP and may help to identify patients at risk of a malignancy., (© 2018 British Association of Dermatologists.)

Importance: Anti-type VII collagen autoantibodies are often detectable in patients with bullous systemic lupus erythematosus (BSLE). However, the timing of their appearance preceding the onset of disease is unknown to date., Observations: We report the case of a 50-year-old woman with a history of SLE who was seen with vesicles and bullae around her lips, trunk, axillae, arms, and thighs. Histologic analysis and immunofluorescence and immunoblot studies confirmed the diagnosis of BSLE. Immunoblotting and enzyme-linked immunosorbent assay studies of the patient's serum obtained 3 months before the onset of BSLE showed the presence of anti-type VII collagen autoantibodies. Levels of anti-type VII collagen IgG increased after bullous lesions appeared. Within 1 month after initiating dapsone therapy and increasing the dosage of prednisone, skin lesions promptly resolved. One year after the onset of BSLE, the anti-type VII collagen IgG decreased below levels observed before the inception of the bullous lesions., Conclusions and Relevance: Anti-type VII collagen autoantibodies can precede the clinical appearance of BSLE. The subsequent increase and decrease in levels of circulating anti-type VII collagen autoantibodies, which mirrored skin disease activity, support a potential role in their initiation of disease.

Mice carrying a deletion in the NC14A domain of murine type XVII collagen begin scratching at age 2 months and then develop erosions, subepidermal vesicles, eosinophil-rich skin infiltrates, and autoantibodies directed against a 180 kDa skin protein that appears to be type XVII collagen. These mice represent a bullous pemphigoid animal model featuring pruritus in immunocompetent, mature, and largely unmanipulated animals.

Mucous membrane pemphigoid (MMP), an autoimmune subepithelial blistering disease that predominantly affects the mucous membranes, is usually diagnosed in elderly adults. Early diagnosis of MMP is crucial because it tends to run a chronic and progressive course with the potential for devastating scarring of the mucous membranes that may lead to blindness and airway compromise. A subtype of MMP, anti-laminin-332 MMP, is a rare blistering disorder in which autoantibodies are directed against laminin-332 (formerly epiligrin), a structural protein of the epidermal basement membrane. Herein we report what we believe to be the youngest patient diagnosed with anti-laminin-332 MMP, a 9-year-old girl with disease affecting only the oral, pharyngeal, and laryngeal mucosa, with no skin involvement., (© 2013 Wiley Periodicals, Inc.)

IgG antinuclear antibodies (ANAs) are elevated in patients with systemic lupus erythematosus (SLE) compared with patients with discoid lupus erythematosus (DLE). To provide an expanded immunologic view of circulating ANAs in lupus patients, we compared the expressions of IgG, IgM, and IgA ANAs in DLE and SLE patients. In this cross-sectional study, sera from age-, gender-, and ethnic-matched SLE (N = 35), DLE (N = 23), and normal patients (N = 22) were tested for IgG, IgM, and IgA ANAs using enzyme-linked immunosorbent assays (ELISAs) and indirect immunofluorescence (IIF) with monkey esophagus as substrate. ELISAs showed elevated levels of IgG ANA, IgM ANA, and IgG/IgM ANA ratios in SLE patients compared with DLE and normal patients. IgA ANA expression was higher in SLE and DLE patients versus normal patients. IIF studies showed higher percentages of patients positive for IgG, IgM, and IgA ANAs in the SLE group. Higher IgG/IgM ANA ratios in SLE than DLE show enhanced class-switching and a more sustained humoral response in SLE. They also suggest a potential connection of IgM ANAs with disease containment.

Background: B-cell activating factor of the TNF family (BAFF) promotes the maturation and survival of B cells. Because BAFF levels are elevated in systemic lupus erythematosus (SLE) patients, BAFF has been the target of emerging therapies for SLE, such as belimumab. Levels of BAFF and its receptors in discoid lupus erythematosus (DLE) patients are unknown., Objective: To compare skin and blood mRNA and protein levels of BAFF and its receptors BAFF-R, TACI, and BCMA in DLE subjects with (DLE+/SLE+ (N=28)) and without SLE (DLE+/SLE- (N=35)), psoriasis subjects (N=11), and normal subjects (N=42)., Methods: We used quantitative real-time PCR to measure blood and skin BAFF, BAFF-R, TACI, and BCMA mRNA, sandwich ELISAs to measure sera BAFF, and immunohistochemistry to evaluate BAFF and BAFF-R skin protein expression., Results: BAFF mRNA and protein levels were highest in DLE+/SLE+blood, followed by DLE+/SLE-, psoriasis, and normal blood. BAFF protein also correlated with anti-nuclear antibodies, and autoantibodies against double-stranded DNA, single-stranded DNA, and ribonucleoprotein, and Systemic Lupus Erythematosus Disease Activity Index scores in DLE patients. While showing no difference between DLE+/SLE+ and DLE+/SLE- skin, BAFF and its receptors mRNA were up-regulated in DLE skin vs. normal and psoriasis skin. DLE skin had higher percentages of BAFF-R⁺ inflammatory cells, likely T cells and macrophages, than psoriasis and normal skin., Conclusions: BAFF may be a serologic marker of systemic disease in DLE patients. BAFF and its receptors are elevated in DLE skin, suggesting that targeted therapies against these proteins could treat refractory DLE patients., (Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: To provide research support that develops and retains leaders, educators, and investigators in dermatology and cutaneous biology, the Dermatology Foundation (DF) has designed and implemented a comprehensive Career Development Award (CDA) Program., Objective: To assess the impact of the DF's 3-year CDA, a comprehensive survey of recipients who received this mechanism of support between 1990 and 2007 was performed., Methods: Of 196 individuals receiving a DF CDA, 181 were identified and asked to complete a comprehensive questionnaire concerning their career status, employment history, professional rank, and record of independent research funding (private foundation, federal, other). A personal assessment of the impact of this funding on these individuals' career trajectory was also requested., Results: Eighty percent of 181 CDA recipients identified currently hold full- or part-time positions in academic medicine. The faculty rank of 112 survey respondents included 46 assistant professors (41%), 41 associate professors (37%), 18 professors (16%), and 7 division or departmental chairs (6%). Of respondents, 84% reported that they have received subsequent independent research funding; 95 of these individuals (86%) have received funding from a federal agency (235 federal grants awarded to date with funding >$318M)., Limitations: The study was retrospective and self-reported; some awardees did not respond to the survey., Conclusions: The DF's CDA Program has succeeded in supporting the early career development of talented investigators, educators, and leaders; fostered the promotion and retention of these individuals in academic medicine; and nucleated numerous investigative careers that have successfully acquired independent research funding., (Copyright © 2012 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

The therapeutic approach to mucous membrane pemphigoid is site specific, with the goal of preserving function for patients with chronic and treatment-resistant disease. The involvement of certain mucosal sites (ie, ocular, laryngeal, esophageal, nasopharyngeal, and anogenital) is high risk and warrants more aggressive intervention. Control of the disease must be balanced with minimizing the sequelae of long-term exposure to systemic glucocorticosteroids and/or other immunosuppressives. Timely interventions and multidisciplinary management are essential in preventing disability., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Mucous membrane pemphigoid (MMP) is the clinical phenotype of a group of autoimmune blistering diseases characterized by autoantibodies directed against different structural proteins in epidermal basement membranes. The clinical course and prognosis of MMP are affected by the specific autoantigen targeted, the titer and bioactivity profile of corresponding autoantibodies, and the specific mucosal sites of disease activity. Irreversible scarring and loss of function must be prevented by early diagnosis and appropriate interventions., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Bullous pemphigoid (BP) is a subepidermal autoimmune disease characterized by a humoral response to an epidermal basement membrane (BM) component, BP antigen 2 (BPAG2). BP patients have IgG autoantibodies against an immunodominant BPAG2 extracellular domain termed NC16A as well as additional epitopes located both in the intracellular and extracellular domains (ICD and ECD, respectively) of this autoantigen. To study the evolution of humoral responses to BPAG2, sequential serum samples obtained from C57BL/6Ncr mice grafted with otherwise syngeneic skin from transgenic mice expressing human BPAG2 (hBPAG2) in epidermal BM were studied for IgG reactivity to seven ECD and ICD hBPAG2 epitopes. All grafted mice developed specific IgG against hBPAG2 ECD and ICD epitopes. In seven of eight mice, anti-hBPAG2 IgG was initially directed against ECD epitopes; in six mice, humoral responses subsequently targeted additional ECD and ICD BPAG2 epitopes. In contrast to IgG specific for ECD epitopes, IgG against ICD epitopes was present at lower levels, detectable for shorter periods, and non-complement fixing. Interestingly, the appearance of IgG directed against ICD epitopes correlated with the development of graft loss in this experimental model. These studies provide a comprehensive and prospective characterization of the evolution of humoral immune responses to hBPAG2 in vivo.

Non-Herlitz junctional epidermolysis bullosa (nH JEB) is characterized by generalized blisters that predominate in sites exposed to friction, trauma, or heat. Whereas infants and children with nH JEB often appear to resemble patients with other forms of EB, adults with this disorder typically display atrophic scars, hypopigmentation, or hyperpigmentation at sites of healed blisters as well as incomplete alopecia, dystrophic nails, mucous membrane involvement, and dental abnormalities. Mild (or severe) disease early in life may be characterized by the opposite phenotype in adults with nH JEB. Although nH JEB is generally less severe than Herlitz disease, fatalities (especially in neonates) are not uncommon among patients with the former diagnosis.

All mammal neonates receive maternal Abs for protection against pathogenic organisms in the postnatal environment. However, neonates can experience serious adverse reactions if the Abs transferred from the mother recognize self-molecules as autoAgs. In this study, we describe a novel model for autoimmune disease induced by transferred maternal Abs in genetically transformed Ag-humanized mice progeny. Bullous pemphigoid is the most common life-threatening autoimmune blistering skin disease that affects the elderly, in which circulating IgG autoAbs are directed against epidermal type XVII collagen (COL17). We have established a genetically manipulated experimental mouse model in which maternal Abs against human COL17 are transferred to pups whose skin expresses only human and not mouse COL17, resulting in blistering similar to that seen in patients with bullous pemphigoid. Maternal transfer of pathogenic Abs to humanized neonatal mice is a unique and potential experimental system to establish a novel autoimmune disease model.

Skin grafts from mice expressing human bullous pemphigoid antigen 2 (hBPAG2) in epidermal basement membrane elicit hBPAG2-specific IgG and graft loss in wild-type (Wt) recipients. Graft loss was dependent on CD4+ T cells and correlated with the production and tissue deposition of hBPAG2-specific IgG. To explore the role of CD40/CD40 ligand (CD40L) interaction in this model, Wt mice grafted with transgenic (Tg) skin were treated with hamster anti-CD40L mAb MR1. In contrast to grafted Wt mice treated with equivalent doses of control IgG, 22 of 23 MR1-treated Wt mice did not develop hBPAG2-specific IgG or graft loss for >or=60 days. MR1-treated mice also accepted a second Tg skin graft without durable production of hBPAG2-specific IgG or graft loss. Moreover, splenocytes and enriched CD4+ T cells from MR1-treated graft recipients transferred un- or hyporesponsiveness to hBPAG2 to other mice and demonstrated a dominant tolerant effect over cotransferred naive splenocytes following adoptive transfer to Rag2-/- mice. Successful inhibition of hBPAG2-specific IgG production and Tg graft loss following CD40:CD40L co-stimulatory blockade in this model provides opportunities to study mechanisms of peripheral tolerance and generate antigen-specific regulatory CD4+ cells-issues of relevance to patients with pemphigoid as well as individuals undergoing gene replacement therapy for epidermolyis bullosa.

Segmental odontomaxillary dysplasia is a rare disorder that unilaterally affects the maxilla causing facial asymmetry and presenting with hypertrichosis and hypoplastic or missing teeth in the affected area. Lip clefting has only been reported in one other case. We report a case of segmental odontomaxillary dysplasia presenting with hypertrichosis of the face, hyperlinear palms with faint erythema, and commissural lip clefting.

Background: Antiepiligrin cicatricial pemphigoid is a mucosal-predominant subepidermal blistering disease associated with an increased relative risk of cancer. In contrast to prior reports showing that anti-laminin (L)-332 autoantibodies are a reliable marker for patients with antiepiligrin cicatricial pemphigoid, a recent report suggested that as many as 40% of patients with bullous pemphigoid (BP) have IgG reactive with this laminin isoform., Objective: We sought to determine whether patients with BP possess circulating IgG anti-L-332 autoantibodies., Methods: Sera from 100 adults with BP were analyzed by indirect immunofluorescence testing of intact skin, immunoblot studies of human keratinocyte (HK) extracts, and a new L-332 enzyme-linked immunosorbent assay. Sera showing reactivity suggestive of anti-L-332 autoantibodies in these assays were further analyzed in immunoblot studies of HK extracellular matrix and immunoprecipitation studies of biosynthetically radiolabeled HK extracts., Results: IgG from all patients with BP bound intact epidermal basement membrane by indirect immunofluorescence microscopy and immunoblotted bullous pemphigoid antigen-1, -2, or both in HK extracts. None of these sera immunoblotted L-332 in HK extracts, although 13 did score above the cut point of a new IgG(4) L-332 enzyme-linked immunosorbent assay (sensitivity = 0.91, specificity = 0.98, Youden index = 0.89). Further analysis of sera from these 13 patients found: (1) all had IgG that bound the epidermal side of 1 mol/L NaCl split skin by indirect immunofluorescence microscopy; (2) none immunoblotted L-332 purified from HK extracellular matrix; and (3) none immunoprecipitated L-332 from biosynthetically radiolabeled HK extracts., Limitations: The basis of false-positive enzyme-linked immunosorbent assay determinations for anti-L-332 IgG among patients with BP is unknown., Conclusion: Anti-L-332 autoantibodies remain a reliable marker for patients with antiepiligrin cicatricial pemphigoid.

Background: Many complications have been reported after orf infection, including lymphadenopathy, secondary bacterial infection, and erythema multiforme. Rare associations with papulovesicular eruptions, including a bullous pemphigoid-like eruption, have also been described., Objectives: Our purpose was to clinically, histologically, and immunologically characterize two cases of orf-induced blistering disease, and to determine whether this condition represented a novel disease entity distinct from known immunobullous diseases., Methods: Two patients were clinically described and skin biopsy specimens were collected for routine histology, direct immunofluorescence studies, and polymerase chain reaction analysis to detect orf viral DNA. Patients' sera were assessed for autoantibodies by indirect immunofluorescence studies using normal-appearing human salt-split skin, by Western blot analysis using keratinocyte extracts, dermal extracts, and recombinant type VII collagen, and immunoprecipitation studies of extracts from biosynthetically radiolabeled human keratinocytes., Results: Two distinctive cases of severe, diffuse blistering eruptions after orf infection are described. In one patient, orf virus DNA was detected in the inciting orf lesion, but not in blistered skin, ruling out disseminated orf infection as a cause of the blisters. In both cases, histology revealed subepidermal blisters with mixed inflammatory cell infiltrates containing neutrophils and eosinophils, direct immunofluorescence microscopy studies demonstrated IgG and C3 deposited at the dermoepidermal junctions of perilesional skin, and indirect immunofluorescence studies demonstrated circulating antibasement membrane IgG that bound the dermal side of salt-split skin. Extensive immunoblot and immunoprecipitation studies failed to reveal a consistent, identifiable autoantigen., Limitations: We describe only two cases. The autoantigen recognized by circulating autoantibodies was not identified., Conclusions: Orf-induced immunobullous disease is a unique disease entity that is clinically and immunologically distinct from bullous pemphigoid, epidermolysis bullosa acquisita, and other known immunobullous conditions.

The pemphigoid group of autoimmune blistering diseases includes distinct entities (bullous pemphigoid, mucous membrane pemphigoid, pemphigoid gestationis, linear IgA dermatosis and lichen planus pemphigoides) that are characterized by relatively consistent clinical, histologic and immunopathologic findings. Patients with these disorders have antibasement membrane autoantibodies that often display pathogenic (blister-forming) activity following passive transfer to experimental animals. Interestingly, such autoantibodies target important structural proteins that promote adhesion of epidermis to epidermal basement membrane in human skin. Autoimmune blistering diseases are characterized by substantial morbidity (for example pruritus, pain, disfigurement) and in some instances mortality. Treatment with systemic immunosuppressives has reduced morbidity and mortality in patients with these diseases.

Anti-epiligrin cicatricial pemphigoid (AECP) is a chronic, mucous membrane-dominated, subepithelial blistering disease characterized by circulating anti-basement membrane zone auto-antibodies to laminin 5. Recent studies have shown that people with AECP have an increased relative risk for malignant tumours. In this report we describe two patients with AECP. In both cases, indirect immunofluorescence demonstrated circulating IgG anti-basement membrane auto-antibodies that bound to the dermal side of 1M NaCl split normal skin. Immunoblotting using laminin 5 purified from keratinocyte extract as a substrate showed that the IgG antibodies of patient 1 reacted with the 140-kDa beta3 subunit of laminin 5 and IgG antibodies of patient 2 reacted with the 165-kDa and 145-kDa alpha3 subunits. Patient 1 had prostate carcinoma and his blistering was resistant to therapy. Patient 2 had no detectable malignancy and treatment with doxycycline was successful.

Bullous pemphigoid antigen 2 (BPAG2) is targeted by autoantibodies in patients with bullous pemphigoid (BP), and absent in patients with one type of epidermolysis bullosa (OMIM #226650). A keratin 14 promoter construct was used to produce transgenic (Tg) mice appropriately expressing human BPAG2 (hBPAG2) in murine epidermal basement membrane (BM). Grafts of Tg skin placed on gender-matched, syngeneic wild type (Wt) or major histocompatibility complex I (MHC I)-/- mice elicited IgG that bound human epidermal BM and BPAG2. Production of such IgG in grafted mice was prompt (detectable within 16+/-2 days), robust (titer > or = 1,280), durable (present > or = 380 days), and correlated with the involution and loss of Tg skin grafts. MHC II-/- mice grafted with Tg skin did not develop anti-hBPAG2 IgG or graft loss indicating that MHC II:CD4+ T cell interactions were crucial for these responses. Tg skin grafts on Wt mice developed neutrophil-rich infiltrates, dermal edema, subepidermal blisters, and deposits of immunoreactants in epidermal BM. This model shows fidelity to alterations seen in patients with BP, has relevance to immune responses that may arise in patients with epidermolysis bullosa following BPAG2 gene replacement, and can be used to identify interventions that may block production of IgG against proteins in epidermal BM.

Anti-epiligrin cicatricial pemphigoid (AECP) is a chronic, autoimmune, subepidermal blistering disease characterized by circulating anti-basement membrane autoantibodies to laminin 5. Recent studies have shown that patients with this form of cicatricial pemphigoid have an increased relative risk for malignant solid tumors. The mechanism underlying this association of AECP and cancer is unknown, but there is accumulating evidence that laminin 5 plays a central role. In this article we report a patient with AECP and co-associated cutaneous T cell lymphoma and summarize all to date reported cases of AECP associated with malignancies. In addition we provide a review of the biology of laminin 5 and its potential role in cancer development.

Transmissibility of characteristic lesions to experimental animals may help us understand the pathomechanism of human autoimmune disease. Here we show that human autoimmune disease can be reproduced using genetically engineered model mice. Bullous pemphigoid (BP) is the most common serious autoimmune blistering skin disease, with a considerable body of indirect evidence indicating that the underlying autoantigen is collagen XVII (COL17). Passive transfer of human BP autoantibodies into mice does not induce skin lesions, probably because of differences between humans and mice in the amino acid sequence of the COL17 pathogenic epitope. We injected human BP autoantibody into Col17-knockout mice rescued by the human ortholog. This resulted in BP-like skin lesions and a human disease phenotype. Humanization of autoantigens is a new approach to the study of human autoimmune diseases.

The "danger model" of immune recognition proposes that the immune system does not differentiate between self and non-self when deciding whether to mount a response, but instead, discerns between that which is dangerous or not dangerous to the host. Danger signals incite inflammatory responses, which can lead to the induction of tissue-specific autoimmunity. Immunosuppressive molecules expressed on selected cells have the potential to regulate tissue-specific inflammation, and consequently, autoimmunity. Recent studies have revealed that CD200, a potent immunoregulatory protein, is expressed on Langerhans cells (LCs) and keratinocytes (KCs) in mouse epidermis. CD200 expression is concentrated on KCs comprising the outer root sheath (ORS) of murine hair follicles (HF). Skin deficient in CD200 is highly susceptible to HF-associated inflammation and immune-mediated alopecia. In this concept review, the results of recent studies on CD200 and its inhibitory receptor, CD200R, are summarized and integrated to yield a model whereby CD200-CD200R interaction attenuates perifollicular inflammation, prevents HF-specific autoimmunity and may protect epidermal stem cells from autoimmune destruction. Further elucidation of the CD200-CD200R signaling pathway in cutaneous tissues may advance understanding of how immune homeostasis is established and maintained in the skin.

We describe a patient with widespread skin lesions and circulating IgG autoantibodies to both type VII collagen and laminin 5. Although autoantibodies to type VII collagen belonged to IgG2, IgG3, and IgG4 subclasses, laminin 5 was targeted exclusively by IgG3 autoantibodies. Interestingly, despite the presence of IgG3 autoantibodies, the patient's serum failed to fix complement to the dermoepidermal junction. In addition, these autoantibodies did not recruit and activate leukocytes or induce dermoepidermal separation in skin sectioned by cryostat. We report a most unusual case of an autoimmune subepidermal blistering with an exclusive IgG3 reactivity to laminin 5.

Knowledge of the pathophysiology of immunobullous diseases has been advanced by the demonstration that passive transfer of antibodies against skin autoantigens can induce blisters in experimental animals with clinical, histologic, and immunopathologic features similar to those seen in human patients. In this issue of the JCI, Liu et al. extend their earlier observations regarding an experimental murine model of bullous pemphigoid by showing that the plasminogen/plasmin signaling cascade synergizes with MMP-9 during the early phase of antibody-induced blister formation in vivo. In a separate study, Sitaru et al. show for the first time to my knowledge that passive transfer of experimental antibodies against type VII collagen create subepidermal blisters in mice that mimic those seen in patients with epidermolysis bullosa acquisita (see the related article beginning on page 870). While the articles by Liu, Sitaru, and their colleagues identify pathways of inflammation and tissue injury that, if interrupted, may abrogate blister formation, in a third study, Payne et al. utilized phage display technologies to isolate human anti-desmoglein monoclonal antibodies from a patient with pemphigus vulgaris and show that such antibodies have restricted patterns of heavy and light chain gene usage - findings suggesting that autoantibodies may represent an additional target for therapeutic interventions in patients with immunobullous diseases (see the related article beginning on page 888).

Background: Anti-epiligrin cicatricial pemphigoid (AECP) is a subepidermal blistering disease characterized by circulating anti-basement membrane autoantibodies to laminin 5., Objective: To evaluate the relative sensitivity of immunoblotting and immunoprecipitation techniques for the detection of anti-laminin 5 antibodies, comparative studies using reference laminin 5 antiserum as well as sera from patients with AECP, other immunobullous diseases, and normal volunteers were performed., Methods: Equivalent amounts of protein from five different substrates were studied by immunoblotting; immunoprecipitation experiments examined biosynthetically radiolabeled human keratinocyte (HK) extracts. Results HK extracellular matrix (ECM) was the most sensitive substrate for detection of antibodies to laminin 5; extracts of HKs, A-431 cells and HaCat cells represented alternative test substrates (though the later required higher amounts of protein input). Sera from patients with AECP immunoblotted laminin 5 in HK ECM at end titers exceeding those identified in indirect immunofluorescence microscopy studies of 1 M NaCl split skin. Immunoprecipitation studies found that a 10,000-fold dilution of reference laminin 5 antiserum retained the ability to identify laminin 5. Maximal dilutions of sera from AECP patients retaining the ability to immunoprecipitate laminin 5 ranged from 500 to 5,000., Conclusion: Immunoprecipitation was the most sensitive technique for detection of anti-laminin 5 antibodies, while immunoblotting of HK ECM or HK extracts represented practical alternatives.

CD200 (OX-2) is a transmembrane glycoprotein that transmits an immunoregulatory signal through the CD200 receptor (CD200R) to attenuate inflammatory reactions and promote immune tolerance. CD200 expression in the skin has not been described previously. We now report that freshly isolated cells of the murine epidermis contain a subpopulation of major histocompatibility complex (MHC) class II-negative, CD3-negative keratinocytes that are CD200-positive. CD200 expression was accentuated in keratinocytes comprising the outer root sheath of the murine hair follicle (HF). When syngeneic skin grafts were exchanged between gender-matched wild-type (WT) and CD200-deficient C57BL/6 mice, significant perifollicular and intrafollicular inflammation was observed, eventually leading to the destruction of virtually all HF (alopecia) without significant loss of the CD200-negative grafts. Minimal and transient inflammation was observed in WT grafts, which persisted long term with hair. There was a 2-fold increase in graft-infiltrating T cells in CD200-deficient skin at 14 d. Alopecia and skin lesions were induced in CD200-deficient hosts by adoptive transfer of splenocytes from WT mice previously grafted with CD200-negative skin, but not from mice grafted with WT skin. Collectively, these results suggest that the expression of CD200 in follicular epithelium attenuates inflammatory reactions and may play a role in maintaining immune tolerance to HF-associated autoantigens.