Subunit-Specific Reactivity of Autoantibodies Against Laminin-332 Reveals Direct Inflammatory Mechanisms on Keratinocytes.

Laminin-332 pemphigoid is a rare and severe autoimmune blistering disease, caused by IgG autoantibodies targeting laminin-332 in the dermal-epidermal basement zone. Laminin-332 pemphigoid is characterized by variable inflammatory infiltrate and the predominance of non-complement-fixing antibodies. Given these findings, we hypothesized that IgG autoantibodies to laminin-332 directly resulted in keratinocyte expression of inflammatory factors. We performed RNA-seq on primary human keratinocytes treated with IgG from patients with laminin-332 pemphigoid. Genes for numerous cytokines and chemokines were upregulated, including CSF2, CSF3, CXCL1, CXCL5, CXCL3, CXCL8, CXCL10, CXCL1, IL6, IL7, IL15, IL23, IL32, IL37, TGFB2 as well as metalloproteases. Considering the pro-inflammatory and proteolytic effect of autoantibodies from patients with laminin-332 pemphigoid identified in our initial experiment, we next questioned whether the reactivity against specific laminin subunits dictates the inflammatory and proteolytic keratinocyte response. Then, we treated keratinocytes with IgG from a separate cohort of patients with reactivity against individual subunits of laminin-332. We identified upregulation of IL-1α, IL-6, IL-8, CXCL1, MMP9, TSLP, and GM-CSF at the protein level, most notably in keratinocytes treated with IgG from laminin ß3-reactive patients. We for the first time demonstrated a pro-inflammatory response, similar to that described in keratinocytes treated with IgG autoantibodies from patients with bullous pemphigoid, providing novel insight into the pathogenesis of laminin-332 pemphigoid and laminin-332 biology.

Evaluation of IL8 pathway on the ocular surface: new insights in patients with ocular mucous membrane pemphigoid.

PURPOSE: To evaluate the expression of IL8/CXCL8 cytokine and its receptor CXCR1 in tear film and ocular surface of patients with ocular mucous membrane pemphigoid (oMMP). METHODS: Ten patients with oMMP in the quiescent phase, 20 patients with primary Sjogren syndrome (pSS) and 13 age- and sex-matched healthy controls (HCs) were included in this study. All patients undergone complete eye examination including lacrimal function tests and ocular surface staining assessed by ocular staining score. Ocular mucous membrane pemphigoid (oMMP) staging according to Mondino classification and dry eye severity grade according to Dry Eye Workshop 2007 classification were recorded. Tear samples and conjunctival epithelium were collected. IL-8 tear concentration was measured by enzyme-linked immunosorbent assay, and conjunctival IL8 was analysed by Western blot; conjunctival expression of CXCR1 was evaluated by immunohistochemistry. Il-8 and CXCR1 expression in oMMP patients were compared with HCand pSS patients and correlated with ocular clinical findings. RESULTS: Tear levels of IL-8 were significantly increased in patients with oMMP (260.1 ± 70 pg/ml) when compared to both HCs (98.5 ± 71.35 pg/ml; p = 0.001) and patients with pSS (96.3 ± 87.5 pg/ml; p = 0.001). Conjunctival expression of IL8 and CXCR1 was significantly increased in oMMP patients when compared to both healthy subjects and pSS patients. CONCLUSION: The significant increase of tear and conjunctival IL8 and CXCR1 levels in patients with oMMP when compared to healthy subjects and patients with Sjogren syndrome suggests that changes of IL8 pathway are specific of oMMP and may represent a potential biomarker of the disease and/or therapeutic target.

Ocular mucous membrane pemphigoid: a review.

Ocular mucous membrane pemphigoid (MMP) is a rare, immuno-mediated chronic progressive condition of the conjunctiva characterized by blisters developing from sub-epithelial tissue through disruption of the adhesions between the conjunctival epithelium and the sub-epithelium. Patients with ocular MMP, in many cases, develop profound conjunctival scarring and visual impairment. Furthermore, ocular MMP may lead to a progressive secondary corneal vascularization and to corneal opacification. Ocular MMP is difficult to diagnose during the initial stages because of false negatives during biopsy and variability in the clinical presentation. Most of the current pharmacological treatments aim to control the inflammatory response to reduce the progressive tissue remodeling which leads to the formation of a fibrotic scar. The course and prognosis of ocular MMP depend on the severity and progression of the disease after systemic immunomodulatory therapy. The aim of this review is to provide a comprehensive analysis of the current literature on established and emerging concepts in ocular MMP, with special attention to its clinical presentation, diagnosis, treatment, and pathogenic mechanisms, including the role of some cytokines and growth factors in the development of the disease.

The direct binding of collagen XVII and collagen IV is disrupted by pemphigoid autoantibodies.

The basement membrane zone (BMZ) is framed by hemidesmosomes and extracellular matrix (ECM) including collagen IV (COL4). Hemidesmosomes are multiprotein complexes that include collagen XVII (COL17). BMZ proteins can be targeted in autoimmune subepidermal blistering diseases, e.g., pemphigoid targeting COL17. The blistering mechanisms in pemphigoid have not been fully elucidated, especially in mucous membrane pemphigoid (MMP), which mainly affects the mucosa. In this study, we showed that oral lesions in pemphigoid may be attributed to the inhibition of protein-protein interactions by autoantibodies. Using immunoprecipitation, we revealed that COL17 directly binds to COL4 in normal human keratinocytes and normal human oral keratinocytes. In particular, the C-terminus of COL17 is binding site to COL4 in oral keratinocytes. The precise COL4-binding region on COL17 was determined by protein-protein binding assay to be from amino acid Gly1175 to Asp1340 on the C-terminus. MMP-IgG or mAb recognizing the C-terminus hindered the interaction of COL17 with COL4 in oral keratinocytes. Furthermore, keratinocyte adhesion strength to COL4-coated plates was significantly reduced by the treatment of mAb against the C-terminus. In addition, the inflammatory infiltrates around perilesions were significantly less in MMP compared to BP. These results indicate that pemphigoid IgG targeting the C-terminus plays a pathogenic role in blister formation in the oral mucosa to inhibit protein interactions with less inflammation.

Inflammatory Stress Causes N-Glycan Processing Deficiency in Ocular Autoimmune Disease.

High levels of proinflammatory cytokines have been associated with a loss of tissue function in ocular autoimmune diseases, but the basis for this relationship remains poorly understood. Here we investigate a new role for tumor necrosis factor α in promoting N-glycan-processing deficiency at the surface of the eye through inhibition of N-acetylglucosaminyltransferase expression in the Golgi. Using mass spectrometry, complex-type biantennary oligosaccharides were identified as major N-glycan structures in differentiated human corneal epithelial cells. Remarkably, significant differences were detected between the efficacies of cytokines in regulating the expression of glycogenes involved in the biosynthesis of N-glycans. Tumor necrosis factor α but not IL-1ß had a profound effect in suppressing the expression of enzymes involved in the Golgi branching pathway, including N-acetylglucosaminyltransferases 1 and 2, which are required for the formation of biantennary structures. This decrease in gene expression was correlated with a reduction in enzymatic activity and impaired N-glycan branching. Moreover, patients with ocular mucous membrane pemphigoid were characterized by marginal N-acetylglucosaminyltransferase expression and decreased N-glycan branching in the conjunctiva. Together, these data indicate that proinflammatory cytokines differentially influence the expression of N-glycan-processing enzymes in the Golgi and set the stage for future studies to explore the pathophysiology of ocular autoimmune diseases.

Molecular diagnosis of anti-laminin 332 (epiligrin) mucous membrane pemphigoid.

BACKGROUND: Mucous membrane pemphigoid is a group of chronic subepithelial autoimmune blistering diseases that mainly affect mucous membranes. Laminin 332-specific autoantibodies are present in approximately 1/3 of the patients, being associated with an increased risk of malignancy. Because of the severe complications, an early recognition of the disease allowing a timely therapy is essential. The gold standard methods for detection of laminin 332-specific autoantibodies, including the immunoprecipitation and immunoblotting are non-quantitative, laborious and restricted to a few specialized laboratories worldwide. In addition, the use of radioimmunoassays, although highly sensitive and specific, are laborious, expensive and tightly regulated. Therefore, there is a stringent need for a quantitative immunoassay for the routine detection of laminin 332-specific autoantibodies more broadly available to diagnostic laboratories. The aim of this study was to compare different antigenic substrates, including native, recombinant laminin 332 and laminin 332-rich keratinocyte extracellular matrix, for development of an ELISA to detect autoantibodies in mucous membrane pemphigoid. RESULTS: Using a relatively large number of sera from MMP patients with well-characterized autoantibody reactivity we show the suitability of ELISA systems using laminin 332 preparations as adjunct diagnostic tools in MMP. While glycosylation of laminin 332 does not appear to influence its recognition by MMP autoantibodies, ELISA systems using both purified, native and recombinant laminin 332 demonstrated a high sensitivity and good correlation with the detection of autoantibodies by immunoblotting. ELISA systems using different laminin 332 preparations represent a feasible and more accessible alternative for a broad range of laboratories. CONCLUSIONS: Our findings qualify the use of immunoassays with the laminin 332-rich preparations as an ancillary diagnostic tool in mucous membrane pemphigoid.

NGF Modulates trkANGFR/p75NTR in αSMA-Expressing Conjunctival Fibroblasts from Human Ocular Cicatricial Pemphigoid (OCP).

OBJECTIVE: In a previous study, we reported the upregulation of Nerve Growth Factor (NGF) and trkANGFR expression in Ocular Cicatricial Pemphigoid (OCP), an inflammatory and remodeling eye disease. Herein, we hypothesize a potential NGF-driven mechanism on fibroblasts (FBs) during OCP remodeling events. To verify, human derived OCP-FBs were isolated and characterized either at baseline or after NGF exposure. MATERIALS AND METHODS: Conjunctival biopsies were obtained from 7 patients having OCP and 6 control subjects (cataract surgery). Both conjunctivas and primary FB cultures were characterised for αSMA, NGF and trkANGFR/p75NTR expression. Subcultures were exposed to NGF and evaluated for αSMA, NGF, trkANGFR/p75NTR expression as well as TGFß1/IL4 release. For analysis, early and advanced subgroups were defined according to clinical parameters. RESULTS: OCP-conjunctivas showed αSMA-expressing FBs and high NGF levels. Advanced OCP-FBs showed higher αSMA expression associated with higher p75NTR and lower trkANGFR expression, as compared to early counterparts. αSMA expression was in keeping with disease severity and correlated to p75NTR. NGF exposure did not affect trkANGFR levels in early OCP-FBs while decreased both αSMA/p75NTR expression and TGFß1/IL4 release. These effects were not observed in advanced OCP-FBs. CONCLUSIONS: Taken together, these data are suggestive for a NGF/p75NTR task in the potential modulation of OCP fibrosis and encourages further studies to fully understand the underlying mechanism occurring in fibrosis. NGF/p75NTR might be viewed as a potential therapeutic target.

Tear film osmolarity in ocular mucous membrane pemphigoid.

PURPOSE: The aim of this study was to evaluate tear film osmolarity in patients with ocular mucous membrane pemphigoid (MMP). METHODS: This observational cross-sectional study included 40 patients with biopsy-proven ocular MMP at Foster stage III referred to the tertiary-care Ocular Immunology and Uveitis Service at the San Raffaele Scientific Institute in Milan from June 2010 to August 2013. We evaluated the following clinical parameters: tear film osmolarity, ocular surface disease symptoms (OSDI) questionnaire, Schirmer test, tear film break-up time (TFBUT), and corneal and conjunctival staining. RESULTS: Forty patients (27 women and 13 men) were enrolled. All patients were undergoing systemic immunosuppressive therapy: 19 patients (47.5%) were on methotrexate, 9 (22.5%) were on mycophenolate mofetil, 9 (22.5%) were on low-dose corticosteroids, and 3 (7.5%) were on azathioprine. The mean osmolarity was 322.90 ± 33.39 mOsm/L, the mean OSDI score was 73.2 ± 17.9, the mean TFBUT was 6.60 ± 3.13 seconds, and the mean Schirmer test value was 4.07 ± 3.58 seconds. Tear film osmolarity significantly correlated with the TFBUT (r = 0.80; P < 0.0001), whereas no clinical correlation was found with the Schirmer test value (r = 0.01; P = 0.40) or with the OSDI score (r = 0.02; P = 0.29). Osmolarity did not turn out to be statistically different in the subgroups according to the Oxford corneal staining scale (P = 0.71) and to the Van Bijsterveld conjunctival staining score (P = 0.31). CONCLUSIONS: Tear osmolarity increased in patients with ocular MMP and correlated with the TFBUT. This result emphasizes the role of evaporative dry-eye condition in patients with ocular MMP. Tear osmolarity may be considered as a useful test in the diagnostic assessment of dry eye associated with MMP and for targeting therapeutic decisions.

Upregulation of Toll-like receptor 5 expression in the conjunctival epithelium of various human ocular surface diseases.

AIMS: To examine the expression of Toll-like receptor (TLR) 5 in the conjunctival epithelium of patients with severe ocular surface diseases. METHODS: Immunohistochemical study of TLR5 was performed on conjunctival tissues obtained from patients undergoing surgical reconstruction of the ocular surface to treat Stevens-Johnson syndrome (SJS) (n=4), ocular cicatricial pemphigoid (OCP) (n=3), chemical eye burn (n=3), and pterygium (n=2), and on nearly normal conjunctival tissues obtained during surgery for four cases of conjunctivochalasis as a control. RESULTS: TLR5 protein was consistently and abundantly expressed in the conjunctival epithelium and detected only at the basal and wing cells. However, in the conjunctival epithelium obtained from the patients with SJS, OCP and chemical eye burns, the TLR5 protein was detected at not only the basal and wing cells but also at the superficial cells. TLR5 protein detected in the pterygium patients mirrored that detected in the controls. CONCLUSIONS: Although TLR5 was normally present on the basal and wing cells of conjunctival epithelium with spatially selective presence, it was expressed on not only the basal and wing cells but also the superficial cells in the conjunctival epithelium of patients with SJS, OCP or chemical eye burns, suggesting that TLR5 might be upregulated in the conjunctival epithelium of these diseases.

Profile of local interleukin expression in a cohort of ocular cicatricial pemphigoid patients.

PURPOSE: We investigated the expression of IL-1, IL-6, IL-12, IL-13, and IL-17 in the conjunctiva of patients with ocular cicatricial pemphigoid (OCP), also labeled as ocular mucous membrane pemphigoid (MMP). METHODS: A retrospective case-control study was done on 5 biopsy-proven OCP subjects and 6 healthy volunteers. Conjunctival specimens were obtained, and the local expression of IL-1, IL-6, IL-12, IL-13, and IL-17 was studied by immunohistochemistry. Clinical and therapeutic features were collected during follow-up. RESULTS: No remarkable IL-1, IL-6, IL-12, IL-13, or IL-17 expression was observed in normal conjunctival specimens. All OCP samples had remarkable amounts of IL-12 and IL-17 expression especially in the epithelium and stroma; there also was stromal overexpression of IL-6. The mean follow-up after the biopsy was 13 months (range 9-15 months). CONCLUSIONS: Our results demonstrated, for the first time to our knowledge, a local overexpression of IL-6, IL-12, and IL-17 in conjunctiva of OCP compared to controls.

Azathioprine-induced EBV-positive mucocutaneous ulcer.

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer was recently described as a clinicopathologic entity occurring secondary to iatrogenic or age-related immune suppression. The histopathology of EBV-positive mucocutaneous ulcer reveals a polymorphous infiltrate including atypical large B-cells and Reed-Sternberg-like cells which are CD20-positive, CD30-positive and EBV-positive. The disorder follows an indolent and self-limited course. We report a case of EBV-positive mucocutaneous ulcer secondary to prolonged use of azathioprine for the treatment of pemphigoid and highlight the need for recognition of this disorder by dermatopathologists and dermatologists.

Pharmacokinetics study about topical clobetasol on oral mucosa.

BACKGROUND: Clobetasol is the most potent topical corticosteroid used in oral medicine for muco-cutaneous diseases. Several papers reported about patients with cushingoid appearance, suggesting an adrenal suppression related to clobetasol systemic absorption after local application. Owing to the lack of studies, our goal is to assess whether transmucosal assimilation, after its application on oral mucosa, really occurs and to define clobetasol pharmacokinetics profile. METHODS: Data were recorded by collecting blood samples both on 10 patients in clobetasol therapy and on 14 healthy volunteers instructed about standardized clobetasol applications. A new technique of analytical chemistry was employed to detect its serum concentrations. RESULTS: Clobetasol absorption was ascertained, showing a certain accumulation rate. Different levels have been found in relation to oral disease and individual features (as smoking habits and presence of oral mucosa erosion). CONCLUSIONS: Our study validates clobetasol systemic transmucosal absorption, also recommending a careful monitoring of patients in corticosteroid therapy to avoid local and systemic adverse effects.

Reciprocal altered expression of E-cadherin and P-cadherin in mucous membrane pemphigoid.

E- and P- cadherins are involved in the selective adhesion of epidermal cells. To gain insight into the role of cadherins on the acantholysis of keratinocytes and further investigate the pathogenesis of Mucous Membrane Pemphigoid, we examined the expression of P-cadherin and E-cadherin, in normal human oral mucosa, lesional and peri-lesional mucosa in MMP. Twenty-nine samples from paraffin-embedded specimens of MMP were used for the study. Five specimens of healthy oral mucosa were evaluated as control group. To evaluate the E- and P-Cadherin expression, a mean percentage of positive cells was determined from the percentage of positive cells derived from the analysis of 100 cells in ten random areas at x400 magnification. It was observed that E-cadherin was weakly and discontinuously expressed on the epithelial layers of pemphigoid mucosa, while it was intensively expressed on all keratinocytes in normal human skin. In contrast, P-cadherin was strongly expressed throughout the entire epidermal layer in MMP samples, although its expression is restricted to the basal cell layer in normal human skin. Statistical analyses showed that the percentage of E-cadherin positive cells in the epithelium of pemphigoid cases was significantly decreased compared with that in normal human mucosa. There was a significant increase in the percentage of P-cadherin positive cells in the epithelial layers of MMP compared with normal human mucosa. The present study showed that there is downregulation of E-cadherin expression and upregulation of P-cadherin expression in MMP mucosa, which may be involved in the pathogenesis of MMP.

Membrane array analysis of tear proteins in ocular cicatricial pemphigoid.

PURPOSE: To explore non-invasive, protein-based, membrane array technology as a means to evaluate the global immune and angiogenic profile of tear proteins in patients with active ocular cicatricial pemphigoid (OCP). METHODS: Forty-three proteins consisting of cytokines, angiogenic/growth factors, and immunoinflammatory modulators were measured by membrane array in tear samples of four control patients and four OCP patients during active disease and after treatment. RESULTS: Signals for several distinct and consistent molecular entities were upregulated in all four active OCP tear samples relative to controls. In particular, interleukin-8 and matrix metalloproteinase-9 were elevated during active disease and decreased after systemic immunomodulatory therapy. CONCLUSIONS: Protein array analysis may provide a well-tolerated assay to monitor levels of inflammatory markers in the tears of OCP patients in response to therapy.

Immunohistochemical expression of epithelial cell markers in corneas with congenital aniridia and ocular cicatrizing pemphigoid.

PURPOSE: We investigated the immunohistochemical characteristics of corneal specimens in congenital aniridia and pemphigoid using various corneal markers to determine the status of the corneal epithelium. METHODS: Conjunctivalization was clinically suspected in all corneas. Ten aniridia and seven pemphigoid paraffin-embedded corneal specimens were stained with periodic Schiff reagent (PAS) and antibodies against CK3/12, CK12, CK19, breast cancer resistance protein 1 (BCRP) and p63. RESULTS: Aniridia: six cases contained goblet cells, four were negative. Both groups had cases with (three of six; one of four) and without CK19 positivity and cases with (two of six; three of four) and without p63 positivity. All aniridia cases except two in the goblet cell group were CK3/12- and CK12-positive and BCRP-negative. Pemphigoid: only one of the seven cases contained goblet cells. This case stained positively for CK19, 3/12, 12 and p63 and negatively for BCRP. The other six cases were positive for CK3/12, five of which were positive for CK12; only one case was CK19-positive. Three cases were p63-positive and two BCRP-positive. The CK12 staining was heterogenous in most cases and was often found in the superficial layer. CONCLUSION: Three different stages of epithelial characteristics were found in congenital aniridia and pemphigoid: (i) CK19-negative and inhomogenous CK12-positive cases indicating epithelium mainly from (partly) CK12-deficient limbal stem cells; (ii) CK19- and/or goblet cell-positive and CK12-positive cases with their epithelia originating from CK12-deficient limbal stem cells and from incursing conjunctival cells; and (iii) CK19-positive and CK12-negative cases consisting of conjunctival cells alone.

The relationship between preoperative clinical scores and immunohistological evaluation of surgically resected tissues in chronic severe ocular surface diseases.

PURPOSE: To clarify the relationship between clinical symptoms and histological status in patients with ocular cicatricial pemphigoid (OCP) and Stevens-Johnson syndrome (SJS). METHODS: Clinical symptoms of four OCP and eight SJS patients in the chronic phase were scored with our recently proposed grading system. The histological status of the pannus tissue removed from the corneal surface during surgery was investigated using immunohistological techniques. RESULTS: All participants showed total loss of the palisades of Vogt and conjunctivalization of the entire corneal surface. All pannus tissues expressed the conjunctival epithelium marker CK4/13. The pannus tissue in clinically keratinized SJS expressed skin epidermal major cytokeratins, but the tissues of nonkeratinized SJS did not. CONCLUSIONS: Clinical observation and the use of our recently proposed grading system agreed with the immunohistological status with respect to keratinization, cell proliferation, and corneal/conjunctival cell typing. These findings facilitate our understanding of the pathogenesis of OCP and SJS, and will hopefully contribute to the development of future treatment strategies and improve predictions of the postoperative prognosis of ocular surface reconstruction in patients with OCP and SJS.

Conjunctival interleukin-13 expression in mucous membrane pemphigoid and functional effects of interleukin-13 on conjunctival fibroblasts in vitro.

Interleukin-13 (IL-13) is the dominant effector cytokine of fibrosis in pulmonary and liver disease. Excessive conjunctival fibrosis in the immunobullous disease ocular mucous membrane pemphigoid (MMP) causes blindness; the pathogenesis of scarring in this disease is incompletely understood. To determine whether IL-13 is involved in conjunctival fibrosis in MMP, we studied the expression of IL-13 in ocular MMP patients before and after systemic immunosuppression and examined the effects of IL-13 on normal human conjunctival fibroblasts. We found high stromal cell expression of IL-13 in active ocular MMP by immunohistochemistry; 80% of these cells were CD3-positive T cells. Following immunosuppression, in clinically uninflamed, treated, ocular MMP patients, the number of IL-13 positive cells was significantly reduced, but this was still fourfold greater than in normal conjunctiva. IL-13 stimulated collagen lattice contraction and migration, and decreased production of mmp-3 and mmp-10 by human conjunctival fibroblasts. The addition of T cell culture supernatant to IL-13 synergistically augmented fibroblast migration. IL-13 also up-regulated surface expression of HLA-DR, CD80, CD40, and CD154 by conjunctival fibroblasts, suggesting a potential mechanism for fibroblast-T cell cross talk, via which fibroblasts may actively engage in perpetuating chronic inflammation and continued fibrosis. Together, these findings suggest that IL-13 is involved in conjunctival fibrosis in MMP, and that IL-13 has both profibrotic and pro-inflammatory effects on human conjunctival fibroblasts.