Low pH condition impairs BP-IgG binding to the basement membrane zone

Bullous pemphigoid (BP), an autoimmune subepidermal blistering disease, shows tense blisters associated with urticarial erythema. Tissue-bound Immunoglobulin G (IgG) at the basement membrane zone (BMZ) detected by direct immunofluorescence (DIF) is strong evidence for a diagnosis of BP. The sensitivity of DIF is higher in complement component 3 (C3) than in IgG, but the reason for this different sensitivity is not fully understood. In this study, we performed several ex vivo studies to investigate the possible mechanism of IgG negativity and C3 positivity at the BMZ by DIF in some BP cases. First, sera from BP patients showing IgG negativity by DIF were found to clearly react to the BMZ in their own DIF skin samples. Next, indirect immunofluorescence (IIF) was performed using sera diluted with different pH phosphate-buffered saline (PBS), pH 7.4, 6.0, and 3.0. Patients' sera diluted with pH 7.4 PBS showed linear staining at the BMZ, but sera diluted with pH 6.0 PBS and pH 3.0 PBS showed lower fluorescence intensities. Finally, sections of skin from BP patients were pre-incubated with different pH PBS (pH 3.0, 6.0, and 7.4), followed by staining with anti-human IgG and C3. The fluorescence intensities were notably lower for IgG and C3 that had been pre-incubated with pH 3.0 PBS and pH 6.0 PBS than for IgG and C3 that had been pre-incubated with pH 7.4 PBS. These results suggest that a low pH condition hinders the binding of autoantibodies to the BMZ, that is, the drop in tissue pH induced by inflammation inhibits autoantibodies from depositing at the BMZ. Furthermore, the drop in tissue pH causes tissue-bound autoantibodies to detach from the BMZ. Complement fragments are activated not only on IgG but also on the cell surface of cells close to IgG during complement activation. IgG may detach from the BMZ under low pH condition induced by inflammation, but some complement fragments remain at the BMZ. These phenomena may help to explain why C3 is more sensitive than IgG when DIF is used to diagnose BP.

Diagnosis of autoimmune subepidermal bullous diseases with mucous membrane involvement based on laser-scanning confocal microscopy

BACKGROUND

Mucosal involvement in autoimmune subepidermal blistering disorders (ASBD) may represent the only or predominant localization. Circulating autoantibodies are detected in 50% cases.

OBJECTIVE

The aim of this study was to evaluate the usefulness of fluorescence overlay antigen mapping by laser-scanning confocal microscopy (FOAM-LSCM) to identify ASBD with mucosal involvement in oral mucosa specimens.

MATERIALS & METHODS

Thirty-two ASBD patients, diagnosed based on direct immunofluorescence between 2006 and 2016, were enrolled. Localization of IgG deposits bound at the basement membrane zone, relative to laminin-332 and collagen IV localization, was assessed in vivo.

RESULTS

FOAM-LSCM disclosed four different immunofluorescence patterns. IgG deposits were located above laminin-332, as in bullous pemphigoid (BP-type), in 19% cases and co-localized with laminin-332 (anti-laminin-332-type) in 6% cases. IgG deposits were found below laminin-332 and above collagen IV (mucous membrane pemphigoid-type) in 59% cases, and below collagen IV (epidermolysis bullosa acquisita-type) in 16%. Circulating antibodies were found in 56% cases.

CONCLUSION

The FOAM-LSCM method should be used in order to obtain a definitive diagnosis of ASBD with mucosal involvement, particularly in the presence of negative circulating antibodies.

Autoimmune Subepidermal Bullous Diseases of the Skin and Mucosae: Clinical Features, Diagnosis, and Management

Autoimmune subepidermal blistering diseases of the skin and mucosae constitute a large group of sometimes devastating diseases, encompassing bullous pemphigoid, gestational pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, and anti-p200 pemphigoid. Their clinical presentation is polymorphic. These autoimmune blistering diseases are associated with autoantibodies that target distinct components of the basement membrane zone of stratified epithelia. These autoantigens represent structural proteins important for maintenance of dermo-epidermal integrity. Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease of the skin and mucosae. Although the disease typically presents with a generalized blistering eruption associated with itch, atypical variants with either localized bullous lesions or "non-bullous" presentations are observed in approximately 20% of patients. A peculiar form of BP typically associated with pregnancy is pemphigoid gestationis. In anti-p200 pemphigoid, patients present with tense blisters on erythematosus or normal skin resembling BP, with a predilection for acral surfaces. These patients have antibodies targeting the 200-kDa basement membrane protein. Epidermolysis bullosa is a rare autoimmune blistering disease associated with autoantibodies against type VII collagen that can have several phenotypes including a classical form mimicking dystrophic epidermolysis bullosa, an inflammatory presentation mimicking BP, or mucous membrane pemphigoid-like lesions. Mucous membrane pemphigoid (MMP) is the term agreed upon by international consensus for an autoimmune blistering disorder, which affects one or more mucous membrane and may involve the skin. The condition involves a number of different autoantigens in the basement membrane zone. It may result in severe complications from scarring, such as blindness and strictures. Diagnosis of these diseases relies on direct immunofluorescence microscopy studies and immunoserological assays. Management of affected patients is often challenging. We will here review the clinical and immunopathological features as well as the pathophysiology of this group of organ-specific autoimmune diseases. Finally, we will discuss the diagnostic approach and the principles of management in clinical practice.

High Expression of Collagen XVII Compensates for its Depletion Induced by Pemphigoid IgG in the Oral Mucosa

The basement membrane zone consists of multiple components, including collagen XVII (COL17), which is the target of bullous pemphigoid. To our knowledge, no research has addressed the differences in basement membrane zone components between the skin and oral mucosa; therefore, we investigated the basement membrane zone proteins, with a focus on COL17. The mRNA and protein expression levels of COL17 were significantly higher in oral keratinocytes than in skin keratinocytes. Hemidesmosomal COL17 expression was markedly higher in oral keratinocytes than in skin keratinocytes, and its level was associated with adhesion strength. Oral keratinocytes adhered to the extracellular matrix more tightly than did skin keratinocytes in vitro. Based on these results, we attempt to explain the clinical diversity of bullous pemphigoid. COL17 depletion was more prominent in skin keratinocytes than in oral keratinocytes after treatment with COL17-NC16A mAbs, which have in vivo pathogenicity. COL17 C-terminus mAbs, which are not pathogenic, facilitated COL17 depletion in combination treatment with COL17-NC16A mAbs in both types of keratinocytes. In summary, the greater amount of COL17 in oral keratinocytes than in skin keratinocytes is associated with the higher strength of oral keratinocyte hemidesmosomal adhesion at the basement membrane zone. Our results may explain why bullous pemphigoid blistering tends to be more prevalent in the skin than in the oral mucosa.

The Basement Membranes in Sarcomatoid Carcinomas. An Immunohistochemical Study

Aims

Eight sarcomatoid carcinomas from various anatomical locations were investigated by immunohistochemical staining to laminin, type IV collagen and heparan sulfate proteoglycan, to study the characteristics of basement membranes at the interface between carcinomatous and sarcomatous tissues.

Methods

Paraffin wax embedded tissue sections from representative tumor samples have been stained with specific antibodies, using the peroxidase-antiperoxidase technique.

Results

In all cases several interruptions or discontinuities of the basement membrane staining pattern were seen. In 4 cases, larger defects or complete loss of staining was also noted. At these places, the boundaries between carcinomatous and sarcomatous tissue were often blurred.

Conclusions

Disruption and loss of basement membranes at interface between carcinomatous and sarcomatous tissues is a frequent finding in sarcomatoid carcinomas. These changes could be consistent with an epithelial origin of the sarcomatous component in these tumors by means of an epithelial-mesenchymal conversion mechanism.

Predicting Outcome in Patients with Anti-GBM Glomerulonephritis

BACKGROUND AND OBJECTIVES

Large studies on long-term kidney outcome in patients with anti-glomerular basement membrane (anti-GBM) GN are lacking. This study aimed to identify clinical and histopathologic parameters that predict kidney outcome in these patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective analysis included a total of 123 patients with anti-GBM GN between 1986 and 2015 from six centers worldwide. Their kidney biopsy samples were classified according to the histopathologic classification for ANCA-associated GN. Clinical data such as details of treatment were retrieved from clinical records. The primary outcome parameter was the occurrence of ESRD. Kidney survival was analyzed using the log-rank test and Cox regression analyses.

RESULTS

The 5-year kidney survival rate was 34%, with an improved rate observed among patients diagnosed after 2007 (P=0.01). In patients with anti-GBM GN, histopathologic class and kidney survival were associated (P<0.001). Only one of 15 patients with a focal class biopsy sample (≥50% normal glomeruli) developed ESRD. Patients with a sclerotic class biopsy sample (≥50% globally sclerotic glomeruli) and patients with 100% cellular crescents did not recover from dialysis dependency at presentation. In multivariable analysis, dialysis dependency at presentation (hazard ratio [HR], 3.17; 95% confidence interval [95% CI], 1.59 to 6.32), percentage of normal glomeruli (HR, 0.97; 95% CI, 0.95 to 0.99), and extent of interstitial infiltrate (HR, 2.02; 95% CI, 1.17 to 3.50) were predictors of ESRD during follow-up.

CONCLUSIONS

Dialysis dependency, low percentage of normal glomeruli, and large extent of interstitial infiltrate are associated with poor kidney outcome in anti-GBM GN. Kidney outcome has improved during recent years; the success rate doubled after 2007.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_11_21_CJASNPodcast_18_1_v.mp3.

Diagnostic Value of Linear Fluorescence Along the Basement Membrane of Sweat Gland Ducts in Bullous Pemphigoid

Linear IgG deposits along the basement membrane of adnexa has been proposed to be useful in the diagnosis of bullous pemphigoid (BP), but no controlled studies have been performed. This study evaluated linear IgG fluorescence of the basement membrane of sweat gland ducts (SGD) and other adnexa in perilesional biopsies from patients with BP (n = 64) and controls (n = 82), using direct immunofluorescence microscopy. Fluorescence intensity was graded semi-quantitatively. Positive SGDs were found in 58 (90.6%) patients with BP and 44 (53.7%) controls, a statistically significant difference (p < 0.0001). The sensitivity of positive SGDs for BP was high (90.6%), but the specificity was low (46.3%). Only strong fluorescence intensity was associated with high specificity. In conclusion, positive SGDs in direct immunofluorescence microscopy are highly sensitive for BP; however, only strong fluorescence has acceptable specificity. Weak positivity of SGDs without linear fluorescence of the epidermal basement membrane may not be sufficiently specific for BP.

MST1-dependent vesicle trafficking regulates neutrophil transmigration through the vascular basement membrane

Neutrophils need to penetrate the perivascular basement membrane for successful extravasation into inflamed tissue, but this process is incompletely understood. Recent findings have associated mammalian sterile 20-like kinase 1 (MST1) loss of function with a human primary immunodeficiency disorder, suggesting that MST1 may be involved in immune cell migration. Here, we have shown that MST1 is a critical regulator of neutrophil extravasation during inflammation. Mst1-deficient (Mst1-/-) neutrophils were unable to migrate into inflamed murine cremaster muscle venules, instead persisting between the endothelium and the basement membrane. Mst1-/- neutrophils also failed to extravasate from gastric submucosal vessels in a murine model of Helicobacter pylori infection. Mechanistically, we observed defective translocation of VLA-3, VLA-6, and neutrophil elastase from intracellular vesicles to the surface of Mst1-/- neutrophils, indicating that MST1 is required for this crucial step in neutrophil transmigration. Furthermore, we found that MST1 associates with the Rab27 effector protein synaptotagmin-like protein 1 (JFC1, encoded by Sytl1 in mice), but not Munc13-4, thereby regulating the trafficking of Rab27-positive vesicles to the cellular membrane. Together, these findings highlight a role for MST1 in vesicle trafficking and extravasation in neutrophils, providing an additional mechanistic explanation for the severe immune defect observed in patients with MST1 deficiency.

High titer anti-basement membrane antibodies in a subset of patients with pediatric systemic lupus erythematosus

BACKGROUND/AIMS

There is a critical need for more noninvasive biomarkers to identify nephritis in patients with systemic lupus erythematosus (SLE). Recent studies in a model mouse and an adult SLE patient cohort suggest that anti-basement membrane antibody levels correlate well with lupus activity and kidney injury. The purpose of this study was to assess the anti-basement membrane reactivity in pediatric SLE (pSLE) patients with or without nephritis.

METHODS

Auto-antibodies to basement membrane antigens were assessed using an anti-matrigel ELISA. Endpoint titers were measured in pSLE patients and healthy children, as well as in autoimmune and non-immune mice, with good reproducing capabilities. Findings were also analyzed with respect to the presence or absence of nephritis, dsDNA antibodies, and other manifestations of pSLE.

RESULTS

MRL/lpr mice developed high-titer anti-matrigel antibodies, whereas C57BL/6 mice did not. In a cohort of 21 pSLE patients and 22 pediatric controls, high-titer anti-matrigel IgG, IgM and IgA antibody levels were specific for pSLE. High-titer anti-matrigel IgG3 levels could distinguish with good sensitivity the 13 pSLE patients with a history of nephritis from the 8 non-renal pSLE patients. High-titer anti-matrigel IgG, IgA, IgM or IgG3 did not correlate with positive anti-double stranded DNA, but defined an overlapping subset of patients.

CONCLUSION

The addition of anti-basement membrane antibody testing to serologic testing in pSLE may help to monitor disease activity or to define important subsets of patients with risks for specific disease manifestations.

Immunologically mediated drug-induced acute renal failure

(1) AIN is the most frequent pattern of drug-induced immunologically mediated renal injury. A number of drugs may be responsible for AIN, namely methicillin and other penicillin derivatives, rifampicin, phenindione and sulfonamides. Particular clinical and pathological features often suggest an immune pathogenetic mechanism. IgG anti-TBM and IgE antibodies have been found in only a few cases and it is likely that antibody-mediated and cell-mediated injury may operate in the same patient. (2) Only few examples of drug-induced vasculitis and glomerulonephritis are known, and the pathophysiology of this kind of renal damage is poorly understood.

Immunochemical characterization and quantitation of the human glomerular basement membrane antigen from the urine of patients with glomerular diseases

A soluble glomerular basement membrane (GBM) antigen was detected in the urines of patients with various glomerular diseases including chronic glomerulonephritis, nephrotic syndrome, chronic renal insufficiency, and lupus nephropathy. The urinary GBM antigen (u-GBM) was immunochemically distinct from other renal antigens and other serum components, but it was cross-reactive with trypsinized human GBM antigen (t-GBM). The molecular size of u-GBM was approximately the same as human serum albumin as estimated by elution patterns on Sephadex G-200. The concentration of u-GBM was estimated quantitatively by a single radial radioimmunodiffusion. Although differed from case to case, a rough correlation with the type and/or stage of nephrotic syndrom existed. It was also demonstrated that the amounts of u-GBM decreased in response to steroid therapy of nephrotic syndrome. It was further shown that in a case of membranoproliferative glomerulonephritis, anti-GBM antibody could be eluted from the kidney removed from the patient. These findings imply that the GBM antigen plays an important role in the pathogenesis of human renal diseases. The pathophysiological significance of urinary GBM excretion in renal diseases is also discussed here.

Immunologically induced tubulo-interstitial nephritis: experimental models in rats

Experimental models of immunologically induced tubulo-interstitial nephritis (TIN) in rats are described. Antitubular basement membrane (anti-TBM) nephritis was demonstrated to be a TIN resulting from an antigen antibody reaction. Renal transplant rejection and the local graft-vs-host (GVH) reaction were cell-mediated immune reactions in which the antigen was possibly shared by kidney structures. A cellular immune reaction to locally applied antigens was shown to be the basis for another experimental model of TIN, possibly originating from activated mediator systems.

Glomerular capillary regeneration and endothelial cell apoptosis in both reversible and progressive models of glomerulonephritis

In summary, angiogenetic capillary regeneration with endothelial proliferation occurred among mesangiolytic lesions in Thy-1 GN, and the damaged glomerulus recovered its normal structure with the reconstruction of the capillary network. In anti-GBM GN on WKY rats, the damaged glomerulus showed rare capillary regeneration and progressed to global sclerosis. In Thy-1 GN, endothelial cell apoptosis was found in the regenerated capillaries with endothelial cell hypercellularity. On the other hand, in anti-GBM GN on WKY rats, the number of endothelial cell apoptosis increased during the evolution of glomerular sclerosis. We have concluded that glomerular capillary regeneration plays an essential role in the recovery of damaged glomeruli. Moreover, apoptosis is indispensable in regulating the number of intrinsic endothelial cells. We also found that endothelial apoptosis is important in progression of glomerular sclerosis.

Immunologically mediated tubulo-interstitial nephritis in children

14 children with proven or presumably immunologically mediated tubulo-interstitial nephritis are presented. In 2 patients anti-tubular basement membrane antibodies were detected. In 6 immunofluorescence microscopy showed granular deposits of immunoglobulin and/or complement likely representing interstitial location of immune complexes. The findings by immunofluorescence were not significant in the remaining 6 patients. However, the association of renal disease to extra-renal disorders, namely chronic active hepatitis and ulcerative colitis, or uveitis or the presence of an epithelioid granuloma with multinucleated giant cells suggests that in such patients an immunologic disorder might be responsible for the tubulo-interstitial nephritis.

BP180- and BP230-specific IgG autoantibodies in pruritic disorders of the elderly: a preclinical stage of bullous pemphigoid?

Pruritus increasingly occurs in the elderly population and is associated with a variety of dermatoses of mixed aetiology. Clinical and experimental evidence suggests that senile pruritus may be linked to autoimmune events initiated by loss of self-tolerance against cutaneous autoantigens, which is facilitated by immune ageing processes. T-cell immunity, which underpins the production of pathogenic autoantibodies in autoimmune diseases, is deregulated by immune senescence thereby leading to autoimmune disorders such as bullous pemphigoid (BP). High mortality rates of BP combined with steadily increasing incidence emphasize the need for an effective diagnostic strategy at an early stage. We summarize here the current understanding of immunological alterations during the ageing process, thereby focusing on aberrant T-cell responses against the basement membrane antigens BP180 and BP230, which may eventually lead to the clinical outcome of BP.

Bullous pemphigoid induced by hydrochlorothiazide therapy

The most common subepidermal blistering disorder, bullous pemphigoid (BP) typically occurs in the elderly without any obvious inciting event. 1 Anti-basement membrane zone antibodies are typically detected on direct and indirect immunofluorescence studies. 2 A flu-like prodromal phase with a non-specific urticarial dermatitis may herald the development of the more characteristic tense bullae. 3 Obtaining a thorough medication history is important as a number of pharmacological agents have been reported to trigger this same phenomenon. We report a case of generalized BP induced by hydrochlorothiazide therapy in a 32-year-old male.

Methotrexate as a treatment in ocular cicatricial moderate pemphigoid

CLINICAL CASE

A 73 year-old woman presented with a history of non-specific symptoms and photophobia in both eyes of 1 year progression. The examination revealed a bilateral symblepharon and fornix shortening. Immunohistochemical analysis confirmed the presence of linear deposits of IgG, IgM and C3 along the conjunctival basement membrane. With the diagnosis of Ocular Cicatricial Pemphigoid, systemic treatment with subcutaneous methotrexate was prescribed.

DISCUSSION

We consider such treatment a very effective initial immunosuppressive alternative in patients with moderate conjunctival inflammation and in cases of rapid progression.

Bullous pemphigoid: role of complement and mechanisms for blister formation within the lamina lucida

Bullous pemphigoid (BP), an autoimmune subepidermal blistering skin disease, demonstrates tense blisters with or without widespread erythema, blistering along the lamina lucida, immunoglobulin G and/or complement deposits at the basement membrane zone, and the presence of circulating autoantibodies against hemidesmosomal molecules. These autoantibodies usually react against 180-kDa and/or 230-kDa proteins, designated as BP180 and BP230, respectively. The precise blistering mechanisms after autoantibodies bind to antigens are not fully understood. Immune complexes are thought to initially activate the complement cascade, which may induce activation of proteases and/or cytokines and cause dermal-epidermal separation. However, why does separation run specifically within the lamina lucida in a space as narrow as 500 nm wide? This review mainly focuses on the possible mechanisms of BP-specific blistering and how separation occurs along the lamina lucida, based on existing evidence.

The peri-islet basement membrane, a barrier to infiltrating leukocytes in type 1 diabetes in mouse and human

We provide the first comprehensive analysis of the extracellular matrix (ECM) composition of peri-islet capsules, composed of the peri-islet basement membrane (BM) and subjacent interstitial matrix (IM), in development of type 1 diabetes in NOD mice and in human type 1 diabetes. Our data demonstrate global loss of peri-islet BM and IM components only at sites of leukocyte infiltration into the islet. Stereological analyses reveal a correlation between incidence of insulitis and the number of islets showing loss of peri-islet BM versus islets with intact BMs, suggesting that leukocyte penetration of the peri-islet BM is a critical step. Protease- and protease inhibitor-specific microarray analyses (CLIP-CHIP) of laser-dissected leukocyte infiltrated and noninfiltrated pancreatic islets and confirmatory quantitative real time PCR and protein analyses identified cathepsin S, W, and C activity at sites of leukocyte penetration of the peri-islet BM in association with a macrophage subpopulation in NOD mice and human type 1 diabetic samples and, hence, potentially a novel therapeutic target specifically acting at the islet penetration stage. Interestingly, the peri-islet BM and underlying IM are reconstituted once inflammation subsides, indicating that the peri-islet BM-producing cells are not lost due to the inflammation, which has important ramifications to islet transplantation studies.

Transcutaneous gene gun delivery of hNC16A Induces BPAG2-specific tolerance

Immune recognition and rejection of tissues expressing transfected genes is a major complication of gene replacement therapy for inherited genetic disorders. Owing to the high immunogenicity of human bullous pemphigoid antigen 2 (hBPAG2), the induction and maintenance of tolerance to this neo-antigen is essential to deliver the gene product to patients with epidermolysis bullosa junctionalis. In a skin grafting mouse model, we used gene gun transfection with a construct encoding hNC16A, the immunodominant domain of hBPAG2, to induce antigen-specific immune tolerance. Eighty percent of wild-type mice transfected with hNC16A showed long-term survival of skin grafts expressing hBPAG2. Tolerance was stable and transferable by T cells but not by B cells of tolerant mice to naive hosts. A dense Foxp3(+) regulatory T-cell (T(reg)) infiltrate was noticed in grafts of tolerant mice and depletion of these cells resulted in a loss of tolerance. Taken together, we show that long-lasting hBPAG2-specific tolerance was induced with gene gun delivery of hNC16A through a T(reg)-dependent mechanism. This is of relevance to patients undergoing gene therapy and has broader implications for the treatment of antigen-specific autoimmune diseases.

Functional characterization of an IgE-class monoclonal antibody specific for the bullous pemphigoid autoantigen, BP180

BP180 (collagen XVII) is the target antigen in several autoimmune diseases including bullous pemphigoid (BP). Both IgE and IgG class autoantibodies have been shown to be pathogenic in BP; however, studies designed to elucidate the patho-mechanisms mediated specifically by the IgE-class autoantibodies are limited by the low levels (ng/mL) of IgE in human sera. In this report, we developed mouse IgE class monoclonal antibodies (MAbs) against the immunodominant NC16A domain of the human BP180 protein and characterized two of the resultant MAbs, designated 395A5 and 395D2. Epitope mapping studies revealed that both MAbs target segment 2 of NC16A, as was described for IgE and IgG class BP autoantibodies. Also similar to BP IgE, MAb 395A5 showed indirect immunofluorescence labeling of the basement membrane zone (BMZ) of human skin, stimulated histamine release from mast cells when triggered with NC16A, and induced keratinocyte production of IL-8. The 395D2 MAb was also able to trigger antigen-specific histamine release from mast cells; however, in contrast to BP IgE and 395A5, 395D2 did not label the cutaneous BMZ, nor did it induce IL-8 production in keratinocytes. In summary, these studies underscore the importance of functionally characterizing MAbs generated for use in human disease models. The 395A5 IgE class murine MAb was shown to share several key functional properties with the pathogenically active IgE produced by BP patients. We therefore expect that this MAb will prove to be a useful tool for dissecting the mechanisms used by BP180-NC16A-specific IgE antibodies in the induction of BP skin lesions.

Pemphigoid gestationis

Pemphigoid gestationis is a rare autoimmune subepidermal bullous dermatosis that occurs during pregnancy and postpartum. Diagnosis is made on the basis of the presence of a subepidermal vesicle on routine histologic examination and of linear deposition of complement along the basement membrane zone of perilesional skin. The disorder is accompanied by severe pruritus and polymorphous bullous skin lesions. Clinical diagnosis is confirmed by histology and positive cutaneous immunofluorescence and immunoelectron microscopy tests (linear deposition of C3, with or without immunoglobulin G, along the basement membrane zone, within the lamina lucida, and localized to the proximal part of anchoring filaments of the epidermal fragment of salt-split skin). Enzyme-linked immunosorbent assay for pemphigoid gestationis antibody (BP180) is commercially available. If local treatment fails, systemic corticosteroid therapy should be administered. Oral corticosteroids are the therapeutic mainstay in pregnancy and postpartum. The prognosis is good for mother and child, except that there is a risk of preterm delivery and of moderate fetal growth restriction. Recurrence is possible during subsequent pregnancies. There is no significant maternal morbidity or mortality.

Myeloperoxidase anti-cytoplasmic antibody related crescentic glomerulonephritis in a patient with IgG3λ monoclonal immunoglobulin deposition disease with membranous features

A 68-year-old woman showed rapidly progressive glomerulonephritis based on the fact that she had 1+ proteinuria (1.1 g/day), a 3+ occult blood reaction, blood urea nitrogen of 32.4 mg/dL, serum creatinine of 2.96 mg/dL, and myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibodies (ANCA) at 52 ELISA Unit (normal range: below 10). A renal biopsy demonstrated a bubbling appearance associated with cellular crescent formation with segmental necrosis. Immunofluorescence studies showed granular IgG3λ deposition along the basement membrane and in the mesangial area. This is the first English-language case report describing MPO-ANCA positive crescentic glomerulonephritis in a patient demonstrating monoclonal immunoglobulin deposition disease with mainly membranous features.

Ocular mucous membrane pemphigoid after Lyell syndrome: occasional finding or predisposing event?

PURPOSE

Ocular mucous membrane pemphigoid (OMMP) is an autoimmune disease involving the eye and characterized by subepithelial detachment resulting from an immunologic reaction against conjunctival basal membrane zone (BMZ) antigens. Lyell syndrome (LS) is a drug-induced, T cell-mediated, cytotoxic reaction involving the mucocutaneous areas. Two patients with LS are presented in whom OMMP developed.

DESIGN

Report of 2 cases.

PARTICIPANTS

Two male patients, 80 and 60 years old, with persistent corneal ulcerations, corneal melting, and inflammation some months after an LS episode.

METHODS

Conjunctival biopsy samples were obtained to perform direct immunofluorescence (DIF) and histologic analyses. Indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) also were performed.

MAIN OUTCOME MEASURES

Immunodeposit findings on the conjunctival BMZ obtained by DIF and IIF, inflammatory infiltration of the corneoconjunctival samples studied by histologic analysis, and autoantibodies of patient sera directed against BMZ antigens tested by ELISA.

RESULTS

Direct immunofluorescence analyses showed immunoglobulin G and complement 3 component deposits along the BMZ in a linear pattern. Histologic analysis revealed the presence of eosinophils, neutrophils, and mast cells with fibrin deposition in the substantia propria of both patients; the data confirmed the clinical suspicion of OMMP. The IIF and ELISA results were negative.

CONCLUSIONS

Chronic eye surface injury associated with LS may promote autoimmunization against ocular epithelial BMZ antigens, playing a strategic role in the subsequent onset of OMMP. The occurrence of OMMP after LS could be an occasional finding, or conversely, LS could be an underestimated predisposing factor in the development of OMMP.

Removal of the basement membrane enhances corneal wound healing

Recurrent corneal erosions are painful and put patients' vision at risk. Treatment typically begins with debridement of the area around the erosion site followed by more aggressive treatments. An in vivo mouse model has been developed that reproducibly induces recurrent epithelial erosions in wild-type mice spontaneously within two weeks after a single 1.5 mm corneal debridement wound created using a dulled-blade. This study was conducted to determine whether 1) inhibiting MMP9 function during healing after dulled-blade wounding impacts erosion development and 2) wounds made with a rotating-burr heal without erosions. Oral or topical inhibition of MMPs after dulled-blade wounding does not improve healing. Wounds made by rotating-burr heal with significantly fewer erosions than dulled-blade wounds. The localization of MMP9, β4 integrin and basement membrane proteins (LN332 and type VII collagen), immune cell influx, and reinnervation of the corneal nerves were compared after both wound types. Rotating-burr wounds remove the anterior basement membrane centrally but not at the periphery near the wound margin, induce more apoptosis of corneal stromal cells, and damage more stromal nerve fibers. Despite the fact that rotating-burr wounds do more damage to the cornea, fewer immune cells are recruited and significantly more wounds resolve completely.

IgA anti-p200 pemphigoid

BACKGROUND

Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disorder. Clinically, it may resemble bullous pemphigoid, linear IgA bullous dermatosis, or dermatitis herpetiformis. Immunologically, anti-p200 pemphigoid is characterized by the development of IgG antibodies directed against a basement membrane zone protein with a molecular weight of 200 kDa.

OBSERVATIONS

We report the first case, to our knowledge, of anti-p200 pemphigoid associated with IgA antibodies and having clinical features resembling pemphigus herpetiformis or dermatitis herpetiformis localized on traumatized areas. Histopathological examination of lesional skin showed dermal-epidermal separation and microabscesses composed of neutrophils in the dermal papillae. Direct immunofluorescence disclosed the presence exclusively of linear in vivo-bound IgA along the basement membrane zone. With the use of laser scanning confocal microscopy, in vivo-bound IgA was localized above collagen type IV and colocalized with laminin 332. Indirect immunofluorescence showed circulating IgA antibodies against basement membrane zone at a titer of 1:160 that reacted with the floor of an artificial blister of salt-split skin. Western immunoblot analysis using dermal extract confirmed the reactivity of circulating IgA antibodies with the 200-kDa antigen corresponding to laminin γ1; however, immunoblotting using recombinant protein of 107 amino acid C-terminus of laminin γ1 was negative for circulating IgA antibodies. Immunoelectron microscopy disclosed the reactivity of circulating IgA autoantibodies within the lower lamina lucida.

CONCLUSION

To the best of our knowledge, this is the first case fulfilling the immunopathological criteria for anti-p200 pemphigoid associated with IgA antibodies and having unusual clinical features.