Use of Convolutional Neural Networks for the Detection of u-Serrated Patterns in Direct Immunofluorescence Images to Facilitate the Diagnosis of Epidermolysis Bullosa Acquisita.

The u-serrated immunodeposition pattern in direct immunofluorescence (DIF) microscopy is a recognizable feature and confirmative for the diagnosis of epidermolysis bullosa acquisita (EBA). Due to unfamiliarity with serrated patterns, serration pattern recognition is still of limited use in routine DIF microscopy. The objective of this study was to investigate the feasibility of using convolutional neural networks (CNNs) for the recognition of u-serrated patterns that can assist in the diagnosis of EBA. The nine most commonly used CNNs were trained and validated by using 220,800 manually delineated DIF image patches from 106 images of 46 different patients. The data set was split into 10 subsets: nine training subsets from 42 patients to train CNNs and the last subset from the remaining four patients for a validation data set of diagnostic accuracy. This process was repeated 10 times with a different subset used for validation. The best-performing CNN achieved a specificity of 89.3% and a corresponding sensitivity of 89.3% in the classification of u-serrated DIF image patches, an expert level of diagnostic accuracy. Experiments and results show the effectiveness of CNN approaches for u-serrated pattern recognition with a high accuracy. The proposed approach can assist clinicians and pathologists in recognition of u-serrated patterns in DIF images and facilitate the diagnosis of EBA.

12/15-Lipoxygenase choreographs the resolution of IgG-mediated skin inflammation.

Autoimmune diseases are defined by an immune response against a specific autoantigen, driven by antigen-specific T cells or antibodies. While the mechanisms resolving brief episodes of acute inflammation elicited by microbial components or tissue injury are well understood, the mechanisms resolving tissue inflammation in autoimmune diseases are still largely elusive. We have, therefore, addressed the mechanisms of resolution in IgG-mediated autoimmune diseases using a mouse model of the pemphigoid disease "bullous pemphigoid-like epidermolysis bullosa acquisita" (BP-like EBA) as prototypical example. We found that 12/15-LO is induced in skin lesions of BP-like EBA and is predominantly expressed in eosinophils. Dependent on the expression of 12/15-LO, large amounts of proresolving lipid mediators, are biosynthesized in the skin by the point disease peaks. Their production is timely correlated to the gradual reversal of tissue inflammation. Genetic deficiency in Alox15, the gene encoding 12/15-LO, disrupts this process significantly protracting and aggravating disease. This protraction is associated reduced recruitment of regulatory T cells (Tregs) into lesional skin. Intriguingly, Alox15-/- mice also exhibit reduced recruitment of eosinophils into the skin, and the chemotaxis of cultured Alox15-/- eosinophils towards CCL11/eotaxin-1 is compromised. Finally, we demonstrate that 15-lipoxygenase-1, the human homologue of 12/15-LO is induced in granulocytes in lesional skin of patients suffering from a pemphigoid disease. Collectively, our result uncover key mechanisms resolving IgG-mediated skin inflammation. These mechanisms are orchestrated by 12/15-LO expressed in eosinophils promoting the recruitment of eosinophils and Tregs, which in turn inhibit neutrophils.

Drug Development in Pemphigoid Diseases.

Pemphigoid diseases are organ-specific autoimmune diseases of the skin and/or mucous membranes. They are caused by autoantibodies targeting adhesion molecules located at the dermal-epidermal junction. While the diagnostics of pemphigoid diseases and insights into their pathogenesis have improved significantly, the development of novel treatments that are effective and safe remains an unmet medical need. However, numerous pre-clinical studies and early clinical trials have recently been launched. This review summarizes some pathways leading to drug development in pemphigoid diseases, namely: (i) hypothesis-driven drug development; (ii) omics-based drug development; (iii) drug repurposing; (iv) screening-based drug development; and (v) drug development based on careful clinical observations. Ultimately, it is hoped that this will lead to personalized and curative treatments.

Detection of anti-type VII collagen IgE antibodies in epidermolysis bullosa acquisita.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a rare pemphigoid disease involving autoantibodies to type VII collagen (COL7), a major structural component of anchoring fibrils. IgE autoantibodies to type XVII collagen (BP180) have been identified in bullous pemphigoid (BP), the prototype of pemphigoid diseases. Although the pathogenic relevance of IgG anti-COL7 has been investigated, that of IgE in EBA remains unclear. OBJECTIVES: To reveal the presence and pathogenic relevance of IgE anti-COL7 in EBA. METHODS: We examined IgE antibodies in 109 patients with EBA by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA). RESULTS: IIF with normal human skin revealed IgE reactivity in the basement membrane zone in 29 (26·6%) cases. To verify whether the IgE antibodies were specific to COL7, we performed IIF with 21 clearly positive cases and the skin of a patient with dystrophic EBA, which does not involve COL7. All cases showed negative results, indicating that IgE antibodies were specific to COL7. In a modified IgG COL7 ELISA for IgE, 16 (14·7%) cases were positive (three and 13 cases were negative and positive on IIF, respectively). We compared anti-COL7 IgG and IgE, and found a weak but significant correlation (r = 0·459, P < 0·001). EBA is clinically divided into a mechanobullous (MB; noninflammatory) type and an inflammatory (INF) type resembling BP. Of the IIF-positive cases, 11 of 30 (37%) had INF and nine of 48 (19%) had MB. CONCLUSIONS: This study is the first to demonstrate the presence of circulating anti-COL7 IgE in patients with EBA, which may correlate with the clinical phenotype.

Direct Immunofluorescence of Mechanobullous Epidermolysis Bullosa Acquisita, Porphyria Cutanea Tarda and Pseudoporphyria.

Mechanobullous epidermolysis bullosa acquisita (mEBA) can have a clinical presentation that is very similar to other blistering diseases, such as porphyria cutanea tarda (PCT) and pseudoporphyria. Direct immunofluorescence is an important feature in the diagnosis of mEBA, although features that overlap with PCT and pseudoporphyria have been reported. This retrospective observational study investigated whether direct immunofluorescence can discriminate mEBA from PCT and pseudoporphyria. Biopsies of 13 patients with mEBA, 10 with PCT and 10 with pseudoporphyria were included. In 7 cases of PCT and 4 of pseudoporphyria, direct immunofluorescence showed a pattern at the dermal-epidermal junction that appeared similar to the u-serrated pattern in mEBA. Vessel wall depositions were observed in all 3 diseases, but were more frequent and more intense in PCT and pseudoporphyria than in mEBA. Careful examination of direct immunofluorescence of mEBA vs. PCT and pseudoporphyria revealed different staining patterns, although overlapping features were present. Therefore, integrating all clinical and laboratory data is essential to differentiate between mEBA, PCT and pseudoporphyria.

[Epidermolysis bullosa acquisita]. / Epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a rare acquired subepidermal bullous autoimmune dermatosis, associated with autoantibodies against collagen type VII, the most important component of dermal anchoring fibrils. Blister induction occurs after binding of autoantibodies to collagen type VII, leading to complement activation, recruitment of neutrophils and secretion of proteases. Clinically, the disease is mostly characterized by tense blisters on trauma-exposed body areas which heal with scarring (mechanobullous form of EBA). The second most frequent subtype of EBA is inflammatory EBA, a bullous pemphigoid-like disease associated with pruritus. Involvement of mucous membranes and/or lesions in the head and neck area additionally point to the diagnosis of EBA. The mechanobullous type of EBA and EBA with intensive mucous membrane lesions display a chronic course and are often extremely resistant to therapy. Topical and systemic glucocorticoids, dapsone, colchicine, classical immunosuppressants, anti-CD20 antibodies, immunoadsorption or intravenous immunoglobulins have been reported as treatments.

Serration pattern analysis for differentiating epidermolysis bullosa acquisita from other pemphigoid diseases.

BACKGROUND: Direct immunofluorescence (DIF) microscopy of a skin biopsy specimen is the reference standard for the diagnosis of pemphigoid diseases (PDs). Serration pattern analysis enables the differentiation of epidermolysis bullosa acquisita (EBA) from other PDs using DIF microscopy alone. However, practice gaps need to be addressed in order to implement this technique in the routine diagnostic procedure. OBJECTIVE: We sought to determine and optimize the technical requirements for serration pattern analysis of DIF microscopy and determine interrater conformity of serration pattern analysis. METHODS: We compared serration pattern analysis of routine DIF microscopy from laboratories in Groningen, The Netherlands and Lübeck, Germany with 4 blinded observers. Skin biopsy specimens from 20 patients with EBA and other PDs were exchanged and analyzed. Various factors were evaluated, including section thickness, transport medium, and biopsy specimen processing. RESULTS: The interrater conformity of our 4 observers was 95.7%. Recognition of serration patterns was comparable in samples transported in saline and in Michel's medium and with section thicknesses of 4, 6, and 8 µm. LIMITATIONS: Limitations include our small sample size and the availability of 20 samples that were compared retrospectively. CONCLUSION: DIF serration pattern analysis is not restricted by variation in laboratory procedures, transport medium, or experience of observers. This learnable technique can be implemented as a routine diagnostic method as an extension of DIF microscopy for subtyping PD.

Controlled tetra-Fc sialylation of IVIg results in a drug candidate with consistent enhanced anti-inflammatory activity.

Despite the beneficial therapeutic effects of intravenous immunoglobulin (IVIg) in inflammatory diseases, consistent therapeutic efficacy and potency remain major limitations for patients and physicians using IVIg. These limitations have stimulated a desire to generate therapeutic alternatives that could leverage the broad mechanisms of action of IVIg while improving therapeutic consistency and potency. The identification of the important anti-inflammatory role of fragment crystallizable domain (Fc) sialylation has presented an opportunity to develop more potent Ig therapies. However, translating this concept to potent anti-inflammatory therapeutics has been hampered by the difficulty of generating suitable sialylated products for clinical use. Therefore, we set out to develop the first, to our knowledge, robust and scalable process for generating a well-qualified sialylated IVIg drug candidate with maximum Fc sialylation devoid of unwanted alterations to the IVIg mixture. Here, we describe a controlled enzymatic, scalable process to produce a tetra-Fc-sialylated (s4-IVIg) IVIg drug candidate and its qualification across a wide panel of analytic assays, including physicochemical, pharmacokinetic, biodistribution, and in vivo animal models of inflammation. Our in vivo characterization of this drug candidate revealed consistent, enhanced anti-inflammatory activity up to 10-fold higher than IVIg across different animal models. To our knowledge, this candidate represents the first s4-IVIg suitable for clinical use; it is also a valuable therapeutic alternative with more consistent and potent anti-inflammatory activity.

Case Report of a 21-Year-Old Man With Epidermolysis Bullosa Acquisita.

Epidermolysis bullosa acquisita (EBA) is a rare acquired type of mechanobullous disease affecting the dermal-epidermal junction (DEJ) of trauma prone acral surfaces. It manifests as tense vesicles, bullae, and milia and typically heals as atrophic hypo- or hyperpigmented scars. Classic noninflammatory mechanobullous EBA typically presents at a mean age of 48 years. A 21-year-old man presented with a 2-year history of nonpainful papular-vesicular lesions on his hands, knees, and toes after minor trauma to these areas. Physical exam revealed postinflammatory hypopigmented scarring and milia to the bilateral dorsal hands and bilateral extensor elbows and knees, with tense blisters on the dorsal hand and patella regions. Direct immunofluorescence revealed strong linear IgG and IgM with weak focal positivity for IgA and C3 at the DEJ. Blood work revealed an increased diffuse gamma region of 71 g/L (6-13 g/L) on serum protein electrophoresis. Pathology showed a fibrotic underlying dermis, with subepidermal bullae and separation and no significant inflammation. The patient was started on colchicine. This case showcases an unusual early age of presentation for mechanobullous EBA and illustrates the importance of interpreting pathology in the context of clinical findings and maintaining a high index of suspicion for EBA in younger patients who present with classic findings. This case is unique as it is the first report of an association between EBA and polyclonal gammopathy and could be suggestive of chronic inflammation, which would fit with our patient's chronic history of EBA.

Distinguishing Epidermolysis Bullosa Acquisita From Bullous Pemphigoid Without Direct Immunofluorescence.

BACKGROUND: It has been postulated that periodic acid-Schiff staining of basement membrane can predict direct immunofluorescence patterns seen in epidermolysis bullosa acquisita and bullous pemphigoid. It has also been suggested that the type of inflammatory infiltrate or presence of fraying of basal keratinocytes may differentiate these two conditions. OBJECTIVE: In this study, we aimed to confirm these observations. METHODS: We reviewed 13 cases of direct immunofluorescence-confirmed epidermolysis bullosa acquisita and 19 cases of direct immunofluorescence-confirmed bullous pemphigoid, all with a subepidermal blister in the routinely processed specimen. The gold standard for diagnosis of epidermolysis bullosa acquisita vs bullous pemphigoid was taken to be identification of immune deposits on the dermal side ('floor' for epidermolysis bullosa acquisita) or the epidermal side ('roof' for bullous pemphigoid) of the salt-split direct immunofluorescence specimen. Our tests to distinguish epidermolysis bullosa acquisita from bullous pemphigoid on the routinely processed biopsy included periodic acid-Schiff basement membrane on the blister roof, neutrophilic infiltrate, lack of eosinophilic infiltrate, and absence of keratinocyte fraying. RESULTS: Sensitivity and specificity for each test were as follows: periodic acid-Schiff staining of roof (sensitivity 25%, specificity 95%), neutrophilic infiltrate (sensitivity 54%, specificity 74%), lack of eosinophilic infiltrate (sensitivity 92%, specificity 68%), and absence of keratinocyte fraying (sensitivity 62%, specificity 58%). CONCLUSIONS: Features in the routinely processed biopsy were unable to reliably distinguish between epidermolysis bullosa acquisita and bullous pemphigoid. Direct immunofluorescence on salt-split skin remains the standard for differentiation.

Epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a rare, acquired subepidermal blistering disease. EBA is characterized by autoantibodies to collagen VII,which serves to link the epidermis to the dermis. The two most common presentations of EBA are classical noninflammatory EBA and bullous pemphigoid-like EBA. Diagnosis of EBA can be challenging as it sharesclinical and histopathologic features with other blistering diseases. Treatment is often recalcitrant and will often necessitate multiple therapies. We presenta case of a thirty-six-year-old Chinese man with EBA and review the literature.

Conditional depletion of mast cells has no impact on the severity of experimental epidermolysis bullosa acquisita.

The role of mast cells (MCs) in autoimmunity is the matter of an intensive scientific debate. Based on observations in different MC-deficient mouse strains, MCs are considered as fundamental players in autoimmune diseases. However, most recent data suggest that the outcome of such diseases is strongly affected by the individual mouse strain used. By the use of two c-Kit mutant MC-deficient mouse strains and one c-Kit-independent strain, we here investigated the role of MCs in a systemic Ab transfer model of epidermolysis bullosa acquisita, a subepidermal autoimmune blistering skin disease characterized by autoantibodies against type VII collagen. While C57BL/6J-Kit(W-sh/W-sh) mice developed an unexpected increased blistering phenotype, no significant differences to WT controls were seen in WBB6F1 -Kit(W/W-v) or the novel Mcpt5-Cre iDTR animals. Interestingly, in a local Ab transfer model, which induces a localized disease, we showed that application of high concentrations of anti-COL7 (where COL7 is type VII collagen) Abs induced MC activation and MC-dependent edema formation that did, however, not contribute to blister induction. Our results indicate that in the autoimmune disorder epidermolysis bullosa acquisita MCs do not contribute to the immune-mediated tissue injury. Modern c-Kit mutant-independent MC-deficient mouse strains will help to further redefine the role of MCs in autoimmunity.

Skin microbiota-associated inflammation precedes autoantibody induced tissue damage in experimental epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic autoimmune blistering skin disease characterized by autoantibodies against type VII collagen (COL7). Immunization of SJL/J mice with recombinant murine COL7 results in break of tolerance and skin blisters. Strikingly, despite circulating autoantibodies, the same genetic background and identical environmental conditions, 20% of mice remain healthy. To elucidate the regulation of the transition from the presence of autoantibodies to overt autoimmune disease, we characterized the innate and adaptive immune response of mice that remain healthy after immunization and compared it to mice that developed skin disease. Both clinically healthy and diseased SJL/J mice showed circulating autoantibodies and deposition of complement-fixing IgG2c autoantibodies and C3 at the dermal-epidermal junction. However, only in diseased animals significant neutrophil infiltration and increase in FcgRIV expression were observed in the skin. In contrast, the expression of T cell signature cytokines in the T cell zone of the draining lymph node was comparable between clinically healthy and diseased animals after immunization. Surprisingly, health was associated with a decreased expression of CD11c, TNFA and KC (CXCL1) in the skin prior to immunization and could be predicted with a negative predictive value of >80%. Furthermore, mice that did not develop clinical disease showed a significantly higher richness and distinctly clustered diversity of their skin microbiota before immunization. Our data indicate that the decision whether blisters develop in the presence of autoantibodies is governed in the skin rather than in the lymph node, and that a greater richness of cutaneous bacterial species appears to be protective.

The retinoid-related orphan receptor alpha is essential for the end-stage effector phase of experimental epidermolysis bullosa acquisita.

Genetic studies have added to the understanding of complex diseases. Here, we used a combined genetic approach for risk-loci identification in a prototypic, organ-specific, autoimmune disease, namely experimental epidermolysis bullosa acquisita (EBA), in which autoantibodies to type VII collagen (COL7) and neutrophil activation cause mucocutaneous blisters. Anti-COL7 IgG induced moderate blistering in most inbred mouse strains, while some showed severe disease or were completely protected. Using publicly available genotyping data, we identified haplotype blocks that control blistering and confirmed two haplotype blocks in outbred mice. To identify the blistering-associated genes, haplotype blocks encoding genes that are differentially expressed in EBA-affected skin were considered. This procedure identified nine genes, including retinoid-related orphan receptor alpha (RORα), known to be involved in neurological development and function. After anti-COL7 IgG injection, RORα+/- mice showed reduced blistering and homozygous mice were completely resistant to EBA induction. Furthermore, pharmacological RORα inhibition dose-dependently blocked reactive oxygen species (ROS) release from activated neutrophils but did not affect migration or phagocytosis. Thus, forward genomics combined with multiple validation steps identifies RORα to be essential to drive inflammation in experimental EBA.

Recombinant human IgA1 and IgA2 autoantibodies to type VII collagen induce subepidermal blistering ex vivo.

Subepidermal autoimmune blistering dermatoses (AIBD) are prototypic autoantibody-mediated diseases. In epidermolysis bullosa acquisita (EBA), an autoimmune disease with severe and chronic skin blistering, autoantibodies are directed against type VII collagen. IgG is the predominant autoantibody isotype of EBA, the pathogenicity of which has been demonstrated in a variety of in vivo and ex vivo disease models. In contrast, there is not much evidence for the pathogenicity of IgA, which may appear as the only autoantibody isotype in some EBA patients. To investigate the pathogenic potential of IgA autoantibodies, we generated chimeric V gene-matched human IgA1, IgA2, and control IgG1 autoantibodies directed against type VII collagen. Immobilized immune complexes containing the rIgA1 and rIgA2 autoantibodies induced the dose-dependent release of reactive oxygen species from neutrophil granulocytes, a precondition for blister formation. Moreover, both rIgA1 and rIgA2 induced leukocyte-dependent dermal-epidermal separation in cryosections of human skin. In contrast with rIgG1, neither rIgA1 nor rIgA2 was capable of inducing complement deposition at the dermal-epidermal junction. Because complement activation is a prerequisite for blister induction, this lack of function compared with IgG1 may be compensated for by the stronger activation of neutrophil granulocytes by both IgA1 and IgA2. For IgG-mediated AIBD, immunoadsorption therapy is a convenient treatment modality for the removal of pathogenic autoantibodies, particularly in treatment-resistant cases. The results of this study show the pathogenic potential of IgA autoantibodies and support the development of adsorber matrices for IgA-mediated AIBD.

Heat shock protein 90 is required for ex vivo neutrophil-driven autoantibody-induced tissue damage in experimental epidermolysis bullosa acquisita.

A broad range of immunosuppressive and immunomodulatory effects of heat shock protein 90 (Hsp90) blockade has been described in models of autoimmune bullous diseases, but the direct contribution of this chaperone to neutrophil effector pathways in the context of autoantibody-driven blistering is generally unknown. Therefore, this has been addressed in the current study on the basis of the subepidermal blistering disease epidermolysis bullosa acquisita (EBA) characterized by autoantibodies against type VII collagen, in which a crucial role of neutrophils and both their reactive oxygen species and matrix metalloproteinases in mediating tissue injury has been established. First, the Hsp90 antagonist 17-DMAG dose-dependently inhibited dermal-epidermal separation ex vivo in cryosections of human skin induced by co-incubation of EBA patient autoantibodies with neutrophils from healthy blood donors. Next, 17-DMAG dose-dependently suppressed production and release of reactive oxygen species by human neutrophils induced by both fMLP ± LPS and EBA-specific immune complexes. In addition, co-immunoprecipitation studies revealed that extracellular Hsp90 interacted with secreted matrix metalloproteinases 2 and 12 in sera of EBA patients, suggesting that these basement membrane-degrading proteolytic enzymes are client proteins of Hsp90 and dependent on its chaperone function. Our findings add to the knowledge of the multimodal anti-inflammatory effects of Hsp90 blockade and implicate that Hsp90 is closely involved in the effector mechanisms of neutrophil-driven autoantibody-induced tissue damage, thus being a relevant therapeutic target in patients with neutrophil-mediated autoimmune diseases such as inflammatory types of EBA.

High-yield biopsy technique for subepidermal blisters.

Dermatologists often perform 2 biopsies in patients with widespread tense blisters: one for light microscopy and another for direct immunofluorescence (DIF). Biopsy techniques recommended for blistering diseases with tense blisters are discussed, and illustrations demonstrate an alternative approach utilizing a single punch biopsy. A single punch biopsy is more cost effective and provides the same diagnostic information as the standard 2-biopsy approach for subepidermal blisters plus additional salt-split skin-like diagnostic information. A limitation for bisecting the single punch biopsy specimen is a potential complete separation of the epidermis from the dermis. The single punch biopsy technique is a simple cost-effective method for obtaining necessary diagnostic information when sampling tense blisters in patients with blistering diseases.

Canine epidermolysis bullosa acquisita: a retrospective study of 20 cases.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a rare autoimmune subepidermal blistering disease of dogs and humans. OBJECTIVES: Our objectives were to describe clinical phenotypes, histopathology and treatment outcomes of canine EBA. ANIMALS: Twenty dogs diagnosed with EBA based on a subepidermal blister formation and collagen VII autoreactivity. RESULTS: Most dogs were young (median: 1.2-year-old) with a male-to-female ratio of 2.3:1. Nine of 20 dogs (45%) developed lesions before one year of age and 11 of 20 dogs (55%) were great danes. Tense vesicles and bullae (18 of 20; 90%) and deep erosions and ulcers (20 of 20; 100%) were the most common lesions and these affected predominantly the oral cavity (19 of 20; 95%), pinnae (16 of 20; 80%), axillae (15 of 20; 75%) and footpads (14 of 20; 70%). Histopathology identified neutrophilic perivascular dermatitis (17 of 17; 100%) without or with (12 of 17; 71%) eosinophils, which occasionally equalled (four cases) or outnumbered neutrophils (two cases). Subepidermal vesicles were either devoid of inflammation or contained neutrophils with or without eosinophils, fibrin and/or haemorrhage. A complete remission of skin lesions was obtained in 14 dogs with a median time of 58 days. Glucocorticoids were used in these dogs either as a monotherapy (3 of 14; 21%) or in combination with other immunomodulating drugs (11 of 14; 79%). The median dose of prednisone was 3 mg/kg/day. The remaining six dogs were euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE: Canine EBA is a rare subepidermal blistering disease with an inflammatory phenotype and a predilection for young great danes and male dogs. The outcome of treatment appears more favourable than assumed previously.

[Epidermolysa bullosa acquisita and graft-versus-host disease]. / Épidermolyse bulleuse acquise et réaction du greffon contre l'hôte.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a rare acquired blistering disorder caused by production of auto-antibody directed against type-VII collagen. Autoimmune disorders can occur after allogenic bone marrow transplantation as manifestations associated with chronic graft-versus-host disease (GVHD). To date, there have been 10 cases reported in the literature concerning autoimmune blistering diseases following allogenic stem-cell transplants. Herein we describe a new case involving EBA. OBSERVATION: A 46-year-old woman developed EBA 4 years after allogenic cord blood transplantation for non-Hodgkin T-cell lymphoma complicated by acute digestive and cutaneous GVHD. At physical examination, she had some cutaneous blisters on the abdomen, arms and face, as well as numerous erosions in the buccal cavity. Direct immunofluorescence microscopy revealed linear IgG and C3 deposits along the dermal-epidermal basement membrane zone. Indirect immunofluorescence showed weak IgG G4 anti-basement membrane zone antibodies, which reacted with the dermal side of 1M NaCl-split skin; the autoantibodies were directed against type-VII collagen. This second case of EBA was evocative of a GVHD blistering disease. After the therapeutic failure of dapsone and of combined mycophenolate-prednisone, treatment with rituximab proved effective. DISCUSSION: EBA may form part of the autoimmune signs associated with chronic GVH. The destruction of basement membrane and of epidermal basal cells that occurs in GVH could give rise to autoimmune bullous disease. However, in our patient, in whom manifestation of chronic GVH was restricted to the lungs, it is difficult to rule out the fortuitous onset of EBA, which presented at a sizeable interval after acute GVH.