A Mitochondrial Polymorphism Alters Immune Cell Metabolism and Protects Mice from Skin Inflammation.

Several genetic variants in the mitochondrial genome (mtDNA), including ancient polymorphisms, are associated with chronic inflammatory conditions, but investigating the functional consequences of such mtDNA polymorphisms in humans is challenging due to the influence of many other polymorphisms in both mtDNA and the nuclear genome (nDNA). Here, using the conplastic mouse strain B6-mtFVB, we show that in mice, a maternally inherited natural mutation (m.7778G > T) in the mitochondrially encoded gene ATP synthase 8 (mt-Atp8) of complex V impacts on the cellular metabolic profile and effector functions of CD4+ T cells and induces mild changes in oxidative phosphorylation (OXPHOS) complex activities. These changes culminated in significantly lower disease susceptibility in two models of inflammatory skin disease. Our findings provide experimental evidence that a natural variation in mtDNA influences chronic inflammatory conditions through alterations in cellular metabolism and the systemic metabolic profile without causing major dysfunction in the OXPHOS system.

Optimization of reference gene panels for gene expression analysis in preclinical models of inflammatory skin diseases.

Reverse transcriptase qPCR is the most common method to determine and compare mRNA expression levels and relies on normalization using reference genes. The expression levels of the latter, however, are themselves often variable between experimental conditions, thus compromising the results. Using the geNorm algorithm, we have examined seven genes with respect to their suitability as reference genes for gene analysis in mouse models of skin inflammation, using the antibody transfer model of epidermolysis bullosa acquisita and in the Aldara™ -induced psoriasiform dermatitis. Our results indicate that the combination of at least 2-3 reference genes is required for stable normalization. Notably, the expression of reference genes changed when comparing lesional skin of both models or when comparing lesional to non-lesional skin within one model. This highlights the need for precise selection of reference genes dependent on the specific experimental setup.

Myeloid-Specific Deletion of Mcl-1 Yields Severely Neutropenic Mice That Survive and Breed in Homozygous Form.

Mouse strains with specific deficiency of given hematopoietic lineages provide invaluable tools for understanding blood cell function in health and disease. Whereas neutrophils are dominant leukocytes in humans and mice, there are no widely useful genetic models of neutrophil deficiency in mice. In this study, we show that myeloid-specific deletion of the Mcl-1 antiapoptotic protein in Lyz2 Cre/Cre Mcl1 flox/flox (Mcl1 ΔMyelo) mice leads to dramatic reduction of circulating and tissue neutrophil counts without affecting circulating lymphocyte, monocyte, or eosinophil numbers. Surprisingly, Mcl1 ΔMyelo mice appeared normally, and their survival was mostly normal both under specific pathogen-free and conventional housing conditions. Mcl1 ΔMyelo mice were also able to breed in homozygous form, making them highly useful for in vivo experimental studies. The functional relevance of neutropenia was confirmed by the complete protection of Mcl1 ΔMyelo mice from arthritis development in the K/B×N serum-transfer model and from skin inflammation in an autoantibody-induced mouse model of epidermolysis bullosa acquisita. Mcl1 ΔMyelo mice were also highly susceptible to systemic Staphylococcus aureus or Candida albicans infection, due to defective clearance of the invading pathogens. Although neutrophil-specific deletion of Mcl-1 in MRP8-CreMcl1 flox/flox (Mcl1 ΔPMN) mice also led to severe neutropenia, those mice showed an overt wasting phenotype and strongly reduced survival and breeding, limiting their use as an experimental model of neutrophil deficiency. Taken together, our results with the Mcl1 ΔMyelo mice indicate that severe neutropenia does not abrogate the viability and fertility of mice, and they provide a useful genetic mouse model for the analysis of the role of neutrophils in health and disease.

Epidermolysis Bullosa (EB) Acquisita in an Adult Patient with Previously Unrecognized Mild Dystrophic EB and Biallelic COL7A1 Mutations.

Circulating anti-type VII collagen autoantibodies are frequently detected in patients with recessive dystrophic epidermolysis bullosa (RDEB). However, evidence supporting their pathogenic role in inducing epidermolysis bullosa acquisita (EBA) has been provided for only one individual with dominant dystrophic epidermolysis bullosa (DDEB). We describe here a patient who presented with dystrophic toenails since early childhood and developed trauma-induced skin blisters and oral erosions at age 26 years. Direct immunofluorescence showed IgG deposits with a u-serrated pattern along the cutaneous basement membrane zone, while no change in the expression of collagen VII could be detected by antigen mapping. High-titre anti-collagen VII antibodies were detected by enzyme-linked immunoassay (ELISA). In parallel, sequencing of epidermolysis bullosa (EB) genes identified compound heterozygous COL7A1 missense c.410G>A (p.Arg137Gln) and splicing c.3674C>T (p.Ala1225_Gln1241del) mutations, previously unrecognized in dystrophic epidermolysis bullosa (DEB). Thus, our patient had RDEB "nails-only" and developed mechanobullous EBA in adulthood. These data support a pathogenic role of circulating autoantibodies to collagen VII in inducing EBA in selected patients with DEB. Unforeseen worsening of skin symptoms in DEB should prompt laboratory investigations for EBA.

The Syk Tyrosine Kinase Is Required for Skin Inflammation in an In Vivo Mouse Model of Epidermolysis Bullosa Acquisita.

The inflammatory form of epidermolysis bullosa acquisita is caused by autoantibodies against type VII collagen (C7), a component of the dermal-epidermal junction. We have previously shown that myeloid Src family kinases mediate skin inflammation triggered by anti-C7 antibodies. Here we identify the Syk tyrosine kinase as a critical component of autoantibody-induced skin inflammation downstream of Src family kinases. Immobilized C7-anti-C7 immune complexes triggered neutrophil activation and Syk phosphorylation in a Src family kinase-dependent manner. Bone marrow chimeric mice lacking Syk in their hematopoietic compartment were completely protected from skin inflammation triggered by anti-C7 antibodies despite normal circulating anti-C7 levels. Syk deficiency abrogated the accumulation of CXCL2, IL-1ß, and leukotriene B4 at the site of inflammation and resulted in defective in vivo neutrophil recruitment. Syk-/- neutrophils had a normal intrinsic migratory capacity but failed to release CXCL2 or leukotriene B4 upon activation by immobilized C7-anti-C7 immune complexes, indicating a role for Syk in the amplification of the inflammation process. These results identify Syk as a critical component of skin inflammation in a mouse model of epidermolysis bullosa acquisita and as a potential therapeutic target in epidermolysis bullosa acquisita and other mechanistically related inflammatory skin diseases such as bullous pemphigoid.

Myeloid-related proteins-8 and -14 are expressed but dispensable in the pathogenesis of experimental epidermolysis bullosa acquisita and bullous pemphigoid.

BACKGROUND: Myeloid-related protein-8 (MRP-8) and its heterodimeric partner, MRP-14 belong to the group of danger-associated molecular patterns (DAMPs) and are associated with numerous chronic human disorders. However, their functional role in autoimmunity remains largely unclear. OBJECTIVE: Here, we examined the involvement of MRP-8/-14 in two difficult-to-treat autoimmune blistering diseases, epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP). METHODS: MRP-8/-14 concentrations in the sera of EBA and BP patients were quantified by ELISA. Experimental EBA and BP in mice were induced by transfer of antibodies directed against type VII or XVII collagen, respectively. Expression of MRP-8/-14 was analyzed in skin samples of these experimental mouse models. The functional role of MRP-8/-14 proteins was evaluated by the induction of experimental EBA and BP in MRP-14-deficient mice. RESULTS: We found serum levels of MRP-8/-14 to be elevated in both, EBA and BP patients. Furthermore, in the lesional skin of mice with experimental diseases expression of MRP-8/-14 was increased as compared to healthy controls. However, MRP-14-deficient mice were fully susceptible to experimental disease with a phenotype comparable to that of wild type controls. CONCLUSION: Although MRP-8/-14 expression is highly increased in experimental as well as human disease, these proteins do not contribute to the pathogenesis in the effector phase of EBA and BP.

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.

Caspase-1-independent IL-1 release mediates blister formation in autoantibody-induced tissue injury through modulation of endothelial adhesion molecules.

Although reports documented aberrant cytokine expression in autoimmune bullous dermatoses (AIBDs), cytokine-targeting therapies have not been established in these disorders. We showed previously that IL-6 treatment protected against tissue destruction in experimental epidermolysis bullosa acquisita (EBA), an AIBD caused by autoantibodies to type VII collagen (COL7). The anti-inflammatory effects of IL-6 were mediated by induction of IL-1ra, and prophylactic IL-1ra administration prevented blistering. In this article, we demonstrate elevated serum concentrations of IL-1ß in both mice with experimental EBA induced by injection of anti-COL7 IgG and in EBA patients. Increased IL-1α and IL-1ß expression also was observed in the skin of anti-COL7 IgG-injected wild-type mice compared with the significantly less diseased IL-1R-deficient or wild-type mice treated with the IL-1R antagonist anakinra or anti-IL-1ß. These findings suggested that IL-1 contributed to recruitment of inflammatory cells into the skin. Accordingly, the expression of ICAM-1 was decreased in IL-1R-deficient and anakinra-treated mice injected with anti-COL7. This effect appeared to be specifically attributable to IL-1 because anakinra blocked the upregulation of different endothelial adhesion molecules on IL-1-stimulated, but not on TNF-α-stimulated, cultured endothelial cells. Interestingly, injection of caspase-1/11-deficient mice with anti-COL7 IgG led to the same extent of skin lesions as in wild-type mice. Collectively, our data suggest that IL-1, independently of caspase-1, contributes to the pathogenesis of EBA. Because anti-IL-1ß in a prophylactic setting and anakinra in a quasi-therapeutic setting (i.e., when skin lesions had already developed) improved experimental EBA, IL-1 appears to be a potential therapeutic target for EBA and related AIBDs.

Genome-wide mapping of gene-microbiota interactions in susceptibility to autoimmune skin blistering.

Susceptibility to chronic inflammatory diseases is determined by immunogenetic and environmental risk factors. Resident microbial communities often differ between healthy and diseased states, but whether these differences are of primary aetiological importance or secondary to the altered inflammatory environment remains largely unknown. Here we provide evidence for host gene-microbiota interactions contributing to disease risk in a mouse model of epidermolysis bullosa acquisita, an autoantibody-induced inflammatory skin disease. Using an advanced intercross, we identify genetic loci contributing to skin microbiota variability, susceptibility to skin blistering and their overlap. Furthermore, by treating bacterial species abundances as covariates with disease we reveal a novel disease locus. The majority of the identified covariate taxa are characterized by reduced abundance being associated with increased disease risk, providing evidence of a primary role in protection from disease. Further characterization of these putative probiotic species or species assemblages offers promising potential for preventative and therapeutic treatment development.

Genetic identification and functional validation of FcγRIV as key molecule in autoantibody-induced tissue injury.

Autoantibody-mediated diseases are clinically heterogeneous and often fail conventional therapeutic strategies. Gene expression profiling has helped to identify new molecular pathways in these diseases, although their potential as treatment targets largely remains to be functionally validated. Based on weighted gene co-expression network analysis, we determined the transcriptional network in experimental epidermolysis bullosa acquisita (EBA), a paradigm of an antibody-mediated organ-specific autoimmune disease characterized by autoantibodies directed against type VII collagen. We identified 33 distinct and differentially expressed modules, including Fcγ receptor (FcγR) IV and components of the neutrophil-associated enzyme system in autoantibody transfer-induced EBA. Validation experiments, including functional analysis, demonstrated that FcγRIV expression on neutrophils crucially contributes to autoantibody-induced tissue injury in the transfer model of EBA. Mice lacking the common γ-chain of activating FcγRs, deficient in FcγRIV or treated with FcγRIV function blocking antibody, but not mice deficient in FcγRI, FcγRIIB, FcγRIII or both FcγRI and FcγRIII, were effectively protected from EBA. Skin disease was restored in γ-chain-deficient mice locally reconstituted with neutrophils from wild-type, but not from γ-chain-deficient, mice. Our findings both genetically and functionally identify a novel disease-related molecule, FcγRIV, in an autoantibody-mediated disorder, which may be of importance for the development of novel targeted therapies.

Identification of quantitative trait loci in experimental epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic mucocutaneous autoimmune skin blistering disease. Several lines of evidence underscore the contribution of autoantibodies against type VII collagen (COL7) to the pathogenesis of EBA. Furthermore, EBA susceptibility is associated with the MHC haplotype in patients (HLA-DR2) and in immunization-induced EBA in mice (H2s). The latter study indicated an additional contribution of non-MHC genes to disease susceptibility. To identify non-MHC genes controlling EBA susceptibility, we intercrossed EBA-susceptible MRL/MpJ with EBA-resistant NZM2410/J and BXD2/TyJ as well as Cast mice. Mice of the fourth generation of this four-way autoimmune-prone advanced intercross line were immunized with a fragment of murine COL7 to induce EBA. Anti-COL7 autoantibodies were detected in 84% of mice, whereas deposition of complement at the dermal-epidermal junction (DEJ) was observed in 50% of the animals; 33% of immunized mice presented with overt clinical EBA. Onset of clinical disease was associated with several quantitative trait loci (QTLs) located on chromosomes 9, 12, 14, and 19, whereas maximum disease severity was linked to QTLs on chromosomes 1, 15, and 19. This more detailed insight into the pathogenesis of EBA may eventually lead to new treatment strategies for EBA and other autoantibody-mediated diseases.

Overexpression of the Flii gene increases dermal-epidermal blistering in an autoimmune ColVII mouse model of epidermolysis bullosa acquisita.

Epidermolysis bullosa (EB) is a severe genetic skin fragility syndrome characterized by blister formation. The molecular basis of EB is still largely unknown and wound healing in patients suffering from EB remains a major challenge to their survival. Our previous studies have identified the actin remodelling protein Flightless I (Flii) as an important mediator of wound repair. Here we identify Flii as a novel target involved in skin blistering. Flii expression was significantly elevated in 30 patients with EB, most prominently in patients with recessive dystrophic EB (RDEB) who have defects in production of type VII collagen (ColVII). Using an autoimmune ColVII murine model of EB acquisita (EBA) and an immunocompetent-ColVII-hypomorphic genetic mouse model of RDEB together with murine Flii alleles, we investigated the contribution of Flii to EB. Overexpression of Flii produced severe blistering post-induction of EBA, while decreased Flii reduced blister severity, elevated integrin expression, and improved ColVII production. Flii(+/-) blistered skin showed reduced α-SMA, TGF-ß1, and Smad 2/3 expression, suggesting that decreasing Flii may affect fibrosis. In support of this, Flii-deficient fibroblasts from EBA mice were less able to contract collagen gels in vitro; however, addition of TGF-ß1 restored collagen contraction, suggesting an interplay between Flii and TGF-ß1. Elevated Flii gene and protein expression was further observed in the blisters of ColVII hypomorphic mice, a murine model of RDEB, suggesting that reducing Flii in blistered skin could be a potential new approach for treating patients with EB.

Complement-fixing anti-type VII collagen antibodies are induced in Th1-polarized lymph nodes of epidermolysis bullosa acquisita-susceptible mice.

The environment encountered in secondary lymphoid organs (e.g., lymph nodes) influences the outcome of immune responses. Immunization of mice with type VII collagen, an adhesion protein expressed at the cutaneous basement membrane, induces experimental epidermolysis bullosa acquisita (EBA). In this model, clinical disease is associated with the H2s haplotype of the MHC found in SJL/J mice. Most other strains (e.g., BALB/c, C57BL/6, NZM2410/J) are resistant to clinical disease, despite autoantibody production. Comparison of autoantibody response in EBA-resistant and -susceptible mice showed an IgG2-dominated response in the latter. We hypothesized that EBA susceptibility is due to specific cytokine gene expression in draining lymph nodes (dLN). To challenge this hypothesis, EBA-susceptible (SJL/J) and -resistant (BALB/c, C57BL/6) mice were immunized with type VII collagen, followed by analysis of clinical phenotype, subclasses of circulating and tissue-bound autoantibodies, complement activation, and cytokine gene expression in dLN. Disease manifestation was associated with induction of complement-fixing autoantibodies, confirming previous observations. Furthermore, however, IFN-γ/IL-4 ratio in dLN of EBA-susceptible mice was significantly increased compared with EBA-resistant strains, suggesting a Th1 polarization. Immunization of H2s-congenic C57BL/6 mice (B6.SJL-H2s) led to Th1 polarization in dLN and clinical disease. In addition to their cytokine milieu, EBA-susceptible and -resistant mice also differed regarding the expression of FcγR on peripheral leukocytes, in which a higher FcγRIV expression in SJL/J and B6.SJL-H2s mice, compared with C57BL/6, was associated with skin lesions. In summary, blistering in experimental EBA is regulated by both adaptive (divergent class switch recombination due to polarized cytokine expression) and innate (FcγR expression) immune mechanisms.

Black patients of African descent and HLA-DRB1*15:03 frequency overrepresented in epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune bullous disease (AIBD). However, higher EBA incidence and predisposing genetic factor(s) involving an HLA haplotype have been suspected in some populations. This retrospective study assessed the overrepresentation of black patients with EBA, its link with HLA-DRB1*15:03, and their clinical and immunological characteristics. Between 2005 and 2009, 7/13 (54%) EBA and 6/183 (3%) other-AIBD patients seen consecutively in our department were black (P=10(-6)); moreover 7/13 (54%) black patients and 6/183 (3%) white patients had EBA (P=10(-6)). In addition, between 1983 and 2005, 12 black patients had EBA. Finally, among the 19 black EBA patients, most of them had very atypical clinical presentations, 9 were natives of sub-Saharan Africa, 1 from Reunion Island, 7 from the West Indies, and 2 were of mixed ancestry. HLA-DRB1*15:03 allelic frequencies were 50% for African patients, significantly higher than the control population (P<10(-3)), and 21% for the West Indians (nonsignificant). High EBA frequencies have already been reported in American blacks significantly associated with the HLA-DR2. In conclusion, black-skinned patients developing EBA seem to have a genetic predisposition, and EBA should be suspected systematically for every AIBD seen in this population.

Generation of antibodies of distinct subclasses and specificity is linked to H2s in an active mouse model of epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disease, characterized by antibodies to type VII collagen (COL7). EBA can be induced in mice by immunization with a fragment of the non-collagenous 1 domain of murine COL7. Contrary to other autoimmune diseases, e.g., rheumatoid arthritis, little is known about the genetic susceptibility for EBA. We therefore used the EBA mouse model to address the hypothesis that disease induction depends on the major histocompatibility complex (MHC) haplotype. Mice from different inbred strains were immunized with recombinant murine COL7. Five distinct responses were observed: induction of (i) severe disease in SJL/J (H2s) and female MRL/MpJ (H2k), (ii) mild and transient disease in C57Bl/10.s (H2s), (iii) microscopic blistering in DBA/1J (H2q), (iv) only presence of non-pathogenic autoantibodies in C57Bl/6J (H2b), NZM2410/J (H2z), BXD2 (H2b), and male MRL/MpJ, and (v) complete resistance to EBA in NOD/ShiLtJ (H2g7) and C57Bl/10.q (H2q) mice. Overall, susceptibility to EBA was strongly associated with H2s. In addition, the diseased phenotype was associated with autoantibodies to specific regions of COL7. Our findings show that induction of antibodies with a distinct specificity is linked to the MHC haplotype in experimental EBA. Furthermore, our data are the basis for future studies with the goal of identifying non-MHC EBA susceptibility genes.

Autoimmunity to type VII collagen: epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is an acquired, mechanobullous disease characterized by autoimmunity to type VII collagen. Type VII collagen makes anchoring fibrils, structures that connect the epidermis and its underlying basement membrane zone to the papillary dermis. EBA patients exhibit skin fragility, blisters, scars and milia formation reminiscent of genetic dystrophic epidermolysis bullosa (DEB). DEB patients have diminutive or absent anchoring fibrils due to a genetic defect in the gene encoding type VII collagen. EBA patients have a decrease in normally functioning anchoring fibrils secondary to an abnormality in their immune system in which they produce 'pathogenic' IgG anti-type VII collagen antibodies. The pathogenicity of these autoantibodies has been demonstrated by passive transfer animal models, in which anti-type VII collagen antibodies injected into a mouse produced an EBA-like blistering disease in the animal. EBA has several distinct clinical presentations. It can present with features similar to DEB, bullous pemphigoid, cicatricial pemphigoid, Brunsting-Perry pemphigoid or IgA bullous dermatosis. Treatment for EBA is unsatisfactory, however, some therapeutic success has been reported with colchicine, dapsone, photophoresis, infliximab and intravenous immunoglobulin.

Familial epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is an acquired blistering skin disorder caused by IgG autoantibodies directed against type VII collagen. In contrast to the genetic forms of epidermolysis bullosa, EBA is usually an acquired, sporadic disease. In this report, we describe a family with two cases of EBA in an uncle-nephew pair, and a third family member with asymptomatic circulating anti-type VII collagen antibodies. These findings provide support for the hypothesis that there is a genetic component to EBA.

Epidermolysis bullosa acquisita and neuroendocrine pancreatic cancer - Coincidence or patho-genetic relationship?

The etiology of epidermolysis bullosa acquisita (EBA) is unknown. EBA may be associated with other autoimmune systemic diseases; it also has been described in connection with different malignant tumors, showing complete remission after successful treatment of the tumor. In such cases, EBA may be regarded as a paraneo-plastic dermatosis. We detected a highly differentiated neuroendocrine pancreatic cancer in a 78-year-old woman with EBA. Even thought her tumor was completely removed and the patient has been disease-free for over seven years, a complete regression of her autoimmune bullous dermatosis could not be induced. By using intravenous immunoglobulins in combination with mycophenolate mofetil, further blister formation could be ameliorated.

The alternative pathway of complement activation is critical for blister induction in experimental epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita is a subepidermal blistering disease associated with tissue-bound and circulating autoantibodies against type VII collagen, a major constituent of the dermal-epidermal junction. The passive transfer of Abs against type VII collagen into mice induces a subepidermal blistering disease dependent upon activation of terminal complement components. To further dissect the role of the different complement activation pathways in this model, we injected C1q-deficient, mannan-binding lectin-deficient, and factor B-deficient mice with rabbit Abs against murine type VII collagen. The development and evolution of blistering had a similar pattern in mannan-binding lectin-deficient and control mice and was initially only marginally less extensive in C1q-deficient mice compared with controls. Importantly, factor B-deficient mice developed a delayed and significantly less severe blistering disease compared with factor B-sufficient mice. A significantly lower neutrophilic infiltration was observed in factor B-deficient mice compared with controls and local reconstitution with granulocytes restored the blistering disease in factor B-deficient mice. Our study provides the first direct evidence for the involvement of the alternative pathway in an autoantibody-induced blistering disease and should facilitate the development of new therapeutic strategies for epidermolysis bullosa acquisita and related autoimmune diseases.

Expression profiles of collagens, HSP47, TGF-beta1, MMPs and TIMPs in epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic, uncommon, sub-epidermal blistering disease involving the skin and mucous membranes that heals with scar formation and milia. Collagens, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are important components that play an essential role(s) in matrix remodeling during scar formation. However, the possible involvement of these components in EBA-induced scarring is not yet known. In the present study, we examined the expression profile of collagens, collagen-binding heat shock protein 47 (HSP47), MMPs and their inhibitory enzymes, TIMPs, in matrix remodeling during conjunctival scarring. The involvement of TGF-beta1, a fibrogenic factor, was also studied. Compared to the controls, an increased expression of type I collagen, type III collagen and HSP47 was detected in conjunctival biopsy sections of patient with EBA using immunohistochemistry. Similar increase in the expression of type I collagen, type III collagen and HSP47 was noted in conjunctival fibroblasts obtained from the patient with EBA. Up-regulation in the expression of MMP-1 and MMP-14 was also noted in conjunctival fibroblasts isolated from the patient with EBA, while no significant changes in the expression of MMP-3, MMP-8, MMP-9 and MMP-13 were seen. As for TIMPs, conjunctival fibroblasts isolated from the patient with EBA, grown in vitro, exhibited increased expression of TIMP-1, TIMP-2 and TIMP-3, when compared with fibroblasts grown from control conjunctival tissues, although the expression level varies with different molecules of the same family. Additionally, compared to the control conjunctival fibroblasts, an increased expression of TGF-beta1 was detected in fibroblasts isolated from the conjunctival tissues of patient with EBA. This study suggests that there is up-regulation in the production of collagens (type I and III), collagen-binding protein (HSP47), matrix degrading collagenases (MMP-1 and 14), and their inhibitory enzymes (TIMP-1, 2 and 3) during the process of conjunctival matrix remodeling in the patient with EBA. The presented data is preliminary and could serve as a basis for further studies to enhance our understanding about the molecular mechanisms of conjunctival scarring in patients with EBA.