Mucous membrane pemphigoid: an update

Pediatric limbal stem cell deficiency: An overview of a rarely studied pathology

The cornea is the outermost transparent layer of the eye, and the continuous renewal of the corneal epithelium is important for its transparency. This process is primarily facilitated by corneal stem cells, most of which are found at the limbus. However, any deterioration or damage in this region leads to corneal conjunctivalization and consequent limbal stem cell deficiency (LSCD), which compromises corneal transparency. LSCD is an important condition, especially in the pediatric population, as it can lead to corneal vascularization, opacity and ultimately loss of vision and subsequent amblyopia, unlike adults. Although pediatric LSCD is often due to chemical injuries, as in adults, it is also caused by conditions such as congenital aniridia, Steven Johnson Syndrome and various other immunological disorders. Appropriate and timely treatment in pediatric LSCD is of particular importance in preventing progression to amblyopia, unlike adults. Accurate staging of the disease is essential for the necessary medical and surgical treatment decision. While medical approaches are at the forefront to eliminate the causative agent and improve the ocular surface in reversible cases, it is essential to replace the limbal stem cells lost in advanced disease. For these replacement procedures, it is noteworthy that there is a tendency for minimally invasive methods compared to adults to avoid possible complications due to long life expectancy in children. In conclusion, although there are various reviews on limbal stem cell deficiency (LSCD) in adults, we believe that this review for childhood LSCD will make an important contribution to the literature, since the relevant literature currently reported for the pediatric population is limited.

Diagnostic approach to limbal stem cell deficiency

Limbal stem cell deficiency (LSCD) is an important cause of visual and ocular morbidity. Effective diagnosis and management require a thoughtful and comprehensive evaluation of the ocular surface. This review describes the pathogenesis, diagnosis, and grading of LSCD, as well as characteristic findings via slit lamp examination, in-vivo confocal microscopy, anterior segment optical coherence tomography (AS-OCT), impression cytology, and OCT angiography.

Cell therapy in the cornea: The emerging role of microenvironment

The cornea is an ideal testing field for cell therapies. Its highly ordered structure, where specific cell populations are sequestered in different layers, together with its accessibility, has allowed the development of the first stem cell-based therapy approved by the European Medicine Agency. Today, different techniques have been proposed for autologous and allogeneic limbal and non-limbal cell transplantation. Cell replacement has also been attempted in cases of endothelial cell decompensation as it occurs in Fuchs dystrophy: injection of cultivated allogeneic endothelial cells is now in advanced phases of clinical development. Recently, stromal substitutes have been developed with excellent integration capability and transparency. Finally, cell-derived products, such as exosomes obtained from different sources, have been investigated for the treatment of severe corneal diseases with encouraging results. Optimization of the success rate of cell therapies obviously requires high-quality cultured cells/products, but the role of the surrounding microenvironment is equally important to allow engraftment of transplanted cells, to preserve their functions and, ultimately, lead to restoration of tissue integrity and transparency of the cornea.

Ocular involvement in autoimmune bullous diseases

Autoimmune bullous diseases represent a heterogenous group of disorders caused by autoantibodies against adhesion molecules; the location of the target protein determines the level of cleft formation. The spectrum of ocular lesions in autoimmune bullous diseases can range from mild symptoms to severe involvement with sight impairment and even, in some cases, blindness. In pemphigus vulgaris, the prevalence of ocular involvement has been reported to be between 7% and 26%. The most common clinical sign of ocular pemphigus vulgaris is bilateral conjunctivitis with hyperemia. Ocular involvement also occurs in 41% to 70% of patients with paraneoplastic pemphigus. The main ocular manifestations are bilateral cicatrizing conjunctivitis with symblepharon formation, and shortening of the fornices. In mucous membrane pemphigoid, ocular involvement is seen in 61% to 70% of patients; the most frequent ocular finding is cicatricial conjunctivitis. Patients with autoimmune bullous diseases having common ocular involvement should be assessed by an ophthalmologist to avoid serious complications. Diagnostic procedures and treatment require multidisciplinary care based on the close cooperation between dermatologists and ophthalmologists.

Limbal stem cell diseases

The function of limbal stem/progenitor cells (LSCs) is critical to maintain corneal epithelial homeostasis. Many external insults and intrinsic defects can be deleterious to LSCs and their niche microenvironment, resulting in limbal stem cell dysfunction or deficiency (LSCD). Ocular comorbidities, frequent in eyes with LSCD, can exacerbate the dysfunction of residual LSCs, and limit the survival of transplanted LSCs. Clinical presentation and disease evolution vary among different etiologies of LSCD. New ocular imaging modalities and molecular markers are now available to standardize the diagnosis criteria and stage the severity of the disease. Medical therapies may be sufficient to reverse the disease if residual LSCs are present. A stepwise approach should be followed to optimize the ocular surface, eliminate the causative factors and treat comorbid conditions, before considering surgical interventions. Furthermore, surgical options are selected depending on the severity and laterality of the disease. The standardized diagnostic criteria to stage the disease is necessary to objectively evaluate and compare the efficacy of the emerging customized therapies.

Understanding cornea epithelial stem cells and stem cell deficiency: Lessons learned using vertebrate model systems

Animal models have contributed greatly to our understanding of human diseases. Here, we focus on cornea epithelial stem cell (CESC) deficiency (commonly called limbal stem cell deficiency, LSCD). Corneal development, homeostasis and wound healing are supported by specific stem cells, that include the CESCs. Damage to or loss of these cells results in blindness and other debilitating ocular conditions. Here we describe the contributions from several vertebrate models toward understanding CESCs and LSCD treatments. These include both mammalian models, as well as two aquatic models, Zebrafish and the amphibian, Xenopus. Pioneering developments have been made using stem cell transplants to restore normal vision in patients with LSCD, but questions still remain about the basic biology of CESCs, including their precise cell lineages and behavior in the cornea. We describe various cell lineage tracing studies to follow their patterns of division, and the fates of their progeny during development, homeostasis, and wound healing. In addition, we present some preliminary results using the Xenopus model system. Ultimately, a more thorough understanding of these cornea cells will advance our knowledge of stem cell biology and lead to better cornea disease therapeutics.

Ectodermal Dysplasia: Association with Anti-Basement Membrane Autoantibodies

Ectodermal dysplasia (ED) is a group of several genetic conditions with absence or dysgenesis of at least two ectodermal derivatives: teeth, skin and its appendages including hair, nails, eccrine and sebaceous glands. The most important clinical findings in patients with ED are hypodontia, hypotrichosis, and hypohidrosis, which can lead to episodes of hyperthermia. Few reports have focused on the progressive keratopathy in ED. Cicatrizing conjunctivitis associated with anti-basement membrane autoantibodies has been described. We report a series of three ectodermal dysplasia patients with an ocular phenotype typically seen in ocular mucous membrane pemphigoid; conjunctival immunohistopathology revealed anti-basement membrane autoantibodies in all of them, and systemic immunosuppression proved to be effective in improving symptoms and helping to stabilize ocular surface disease.

Global Consensus on Definition, Classification, Diagnosis, and Staging of Limbal Stem Cell Deficiency

PURPOSE

Despite extensive knowledge gained over the last 3 decades regarding limbal stem cell deficiency (LSCD), the disease is not clearly defined, and there is lack of agreement on the diagnostic criteria, staging, and classification system among treating physicians and research scientists working on this field. There is therefore an unmet need to obtain global consensus on the definition, classification, diagnosis, and staging of LSCD.

METHODS

A Limbal Stem Cell Working Group was first established by The Cornea Society in 2012. The Working Group was divided into subcommittees. Four face-to-face meetings, frequent email discussions, and teleconferences were conducted since then to obtain agreement on a strategic plan and methodology from all participants after a comprehensive literature search, and final agreement was reached on the definition, classification, diagnosis, and staging of LSCD. A writing group was formed to draft the current manuscript, which has been extensively revised to reflect the consensus of the Working Group.

RESULTS

A consensus was reached on the definition, classification, diagnosis, and staging of LSCD. The clinical presentation and diagnostic criteria of LSCD were clarified, and a staging system of LSCD based on clinical presentation was established.

CONCLUSIONS

This global consensus provides a comprehensive framework for the definition, classification, diagnosis, and staging of LSCD. The newly established criteria will aid in the correct diagnosis and formulation of an appropriate treatment for different stages of LSCD, which will facilitate a better understanding of the condition and help with clinical management, research, and clinical trials in this area.

The diagnosis of limbal stem cell deficiency

Limbal stem cells (LSCs) maintain the normal homeostasis and wound healing of corneal epithelium. Limbal stem cell deficiency (LSCD) is a pathologic condition that results from the dysfunction and/or an insufficient quantity of LSCs. The diagnosis of LSCD has been made mainly based on medical history and clinical signs, which often are not specific to LSCD. Methods to stage the severity of LSCD have been lacking. With the application of newly developed ocular imaging modalities and molecular methods as diagnostic tools, standardized quantitative criteria for the staging of LSCD can be established. Because of these recent advancements, effective patient-specific therapy for different stages of LSCD may be feasible.

High-Yield Vulvar Histopathology for the Clinician

Certain adjustable factors may influence how helpful a pathology report is to the clinician. Different biopsy techniques may be preferable based on the type of lesion being biopsied and the background epithelial surface. Key observations from the history and physical examination, possibly with a clinical photograph, are helpful to the pathologist. When reading the pathology report, realize the difficulties arising from definitively classifying some diseases and how treatment can affect the tissue. Finally, avoid miscommunication with the pathologist by understanding current nomenclature of vulvar disease.

Repeat Conjunctival Biopsy after Immunomodulatory Therapy for Ocular Mucous Membrane Pemphigoid

PURPOSE

To evaluate whether conjunctival biopsy findings in patients with ocular mucous membrane pemphigoid (MMP) persist as positive or revert to negative following treatment with immunomodulatory therapy (IMT).

METHODS

Patients with biopsy-proven MMP were treated with IMT for at least 2 years before undergoing repeat conjunctival biopsy for immunofluorescence microscopy. Their records were reviewed and findings evaluated to ascertain which patients' biopsies showed antibody deposition on the conjunctival basement membrane.

RESULTS

Following 2 years of IMT, conjunctival biopsies showed persistent antibody deposition in two patients, and were negative in four patients.

CONCLUSIONS

Conjunctival biopsies in patients with ocular MMP may show reversion to inactive disease following IMT. Post-treatment biopsy might be clinically useful as a means of evaluating the efficacy of therapy in this chronic disease.

Emerging role of antioxidants in the protection of uveitis complications

Current understanding of the role of oxidative stress in ocular inflammatory diseases indicates that antioxidant therapy may be important to optimize the treatment. Recently investigated antioxidant therapies for ocular inflammatory diseases include various vitamins, plant products and reactive oxygen species scavengers. Oxidative stress plays a causative role in both non-infectious and infectious uveitis complications, and novel strategies to diminish tissue damage and dysfunction with antioxidant therapy may ameliorate visual complications. Preclinical studies with experimental animals and cultured cells demonstrate significant anti-inflammatory effects of a number of promising antioxidant agents. Many of these antioxidants are under clinical trial for various inflammatory diseases other than uveitis such as cardiovascular, rheumatoid arthritis and cancer. Well planned interventional clinical studies in the field of ocular inflammation will be necessary to sufficiently investigate the potential medical benefits of antioxidant therapies for uveitis. This review summarizes the recent investigations of novel antioxidant agents for ocular inflammation, with selected studies focused on uveitis.

IgA autoantibodies in the pemphigoids and linear IgA bullous dermatosis

BACKGROUND

Patients with bullous pemphigoid (BP), mucous membrane pemphigoid (MMP) and pemphigoid gestationis (PG) have IgG antibodies against BP180 and BP230, components of the hemidesmosomes. Patients with linear IgA bullous dermatosis (LABD) have IgA autoantibodies against a 97/120-kDa protein which is highly homologous to a shedded fragment of the BP180-ectodomain.

OBJECTIVES

The aim of our study was to determine the incidence of IgA autoantibodies directed against BP180/BP230 in the pemphigoids and LABD and to determine the antigenic regions that are targeted by IgA autoantibodies.

METHODS

Utilizing baculovirus-expressed recombinant BP180 and BP230 proteins, we performed immunoblot analyses for IgA reactivity of sera from patients with BP (n = 30), MMP (n = 10), PG (n = 6), LABD (n = 6) and from control patients with non-related pruritic dermatoses (n = 8).

RESULTS

IgA reactivity against BP180 and/or BP230 was detected in 19/30 of the BP, in 7/10 of the MMP, in 6/6 of the LABD and in 3/6 of the PG sera, respectively, but not in the control group. In all subgroups, the major antigenic site recognized by IgA antibodies was located within the NH(2)-terminus of the BP180-ectodomain, but only a minority of the sera showed also IgA reactivity against the BP180-NC16a-domain. IgA reactivity against the central domain of BP180 was more frequently seen than against its COOH-terminus. IgA against the COOH- and NH(2)-terminus of BP230, respectively, was detected in 6/30 of the BP, 1/10 of the MMP, 1/6 of the LABD and 0/8 control sera.

CONCLUSION

IgA reactivity against BP180 and/or BP230 is a common finding in the pemphigoids.

Long-standing oral ulcers: proposal for a new 'S-C-D classification system'

Persistent oral ulcers and erosions can be the final common manifestation, sometimes clinically indistinguishable, of a diverse spectrum of conditions ranging from traumatic lesions, infectious diseases, systemic and local immune-mediated lesions up to neoplasms. The process of making correct diagnosis for persistent oral ulcers still represents a challenge to clinicians. Major diagnostic criteria should include the clinical appearance of both ulcer and surrounding non-ulcerated mucosa, together with the evaluation of associated signs and symptoms, such as: number (single or multiple), shape, severity of the ulcer(s), conditions of remaining mucosa (white, red or with vesiculo-bullous lesions) and systemic involvement (e.g. fever, lymphadenopathy or evaluation of haematological changes). The aim of this paper was to review the literature relating to persistent oral ulcers and provide a helpful, clinical-based diagnostic tool for recognising long-standing ulcers in clinical dental practice. The authors, therefore, suggest distinguishing simple, complex and destroying (S-C-D system) ulcerations, as each requires different diagnostic evaluations and management. This classification has arisen from studying the current English literature relating to this topic, performed using MEDLINE / PubMed / Ovid databases.

[Mucous membrane pemphigoid with ocular involvement. Part I: Clinical manifestations, pathogenesis and diagnosis]

Mucous membrane pemphigoid is a subepidermal blistering autoimmune disorder characterized by predominant involvement of mucous membranes and the presence of autoantibodies against proteins of the dermal-epidermal junction. Lesions most frequently develop in the oral cavity followed, in descending order of frequency, by conjunctiva, nasopharynx, the anogenital region, skin, larynx, and oesophagus. When the lesions are restricted to the conjunctiva, the term ocular pemphigoid may be applied. Cicatrization of the plica is considered a pathognomonic sign in early disease. Recurrent conjunctival inflammation results in subepithelial fibrosis, which leads to fornix shortening, symblepharon formation and subsequent trichiasis and entropion. Even in the absence of conjunctival inflammation, ankyloblepharon may occur. In end stage disease, limbal stem cell deficiency, tear deficiency, and lid malpositions may occur and result in a total keratinization of the ocular surface. The diagnosis is based on clinical findings and the detection of linear deposits of IgG and/or IgA and/or C3 at the dermal-epidermal junction by direct immunofluorescence microscopy of a perilesional biopsy. Autoantibodies (against type XVII and VII collagen, laminin 5 and 6, alpha6beta4 integrin, BP230) have been detected in patient serum. In the case of ocular involvement, preferential reactivity against beta4 integrin has been described.

Oral mucosal diseases: Mucous membrane pemphigoid

Subepithelial vesiculobullous conditions are chronic autoimmune disorders that arise from reactions directed against components of the hemidesmosomes or basement membrane zones (BMZ) of stratified squamous epithelium to which the term immune-mediated subepithelial blistering diseases (IMSEBD) has been given. Mucous membrane pemphigoid (MMP) is the most common, but variants do exist. Non-immune disorders that involve these epithelial components typically have a genetic basis--the main example being epidermolysis bullosa. All subepithelial vesiculobullous disorders present as blisters and erosions, and diagnosis must be confirmed by biopsy examination with immunostaining, sometimes supplemented by other investigations. No single treatment reliably controls all subepithelial vesiculobullous disorders; the immunological differences within IMSEBD may account for differences in responses to treatment. Currently, as well as improving oral hygiene, immunomodulatory treatment is used to control the oral lesions of MMP, but it is not known if its specific subsets reliably respond to different agents.

Differentiation of mucous membrane pemphigoid subgroups with confocal imaging

OBJECTIVE

Mucous membrane pemphigoid is an immune-mediated subepithelial blistering disease consisting of immunologically heterogeneous subgroups. Differentiation between these subgroups is important because they differ in prognosis. This study uses oral mucosal pemphigoid specimens to investigate the utility of computer-aided fluorescence overlay antigen mapping and laser scanning confocal microscopy to differentiate subgroups of mucous membrane pemphigoid.

STUDY DESIGN

Thirty oral mucosal biopsy specimens were cryosectioned and immunostained, although only 13 could be analyzed due to technical difficulties. In vivo bound antibodies and molecular markers of the basement membrane zone were differentially labeled with fluorescent antibodies. Fluorescent signals were imaged, and the spatial localization of in vivo bound antibodies was compared with the markers and analyzed.

RESULTS

In vivo bound IgG antibodies colocalized with beta4-integrin in 3 cases, with laminin-5 in 8 cases, and with collagen VII in 2 cases.

CONCLUSION

Fluorescence overlay antigen mapping and laser scanning confocal microscopy are useful techniques to differentiate pemphigoid subgroups in oral biopsy specimens.

Transplantation of ex vivo cultured limbal epithelial stem cells: a review of techniques and clinical results

Ex vivo cultured limbal epithelial stem cells have been used successfully to treat corneal limbal stem cell deficiency. We identified 17 reports of the application of this novel cell-based therapy in humans. In addition we identified four reports of the use of culture oral mucosal epithelial cells to treat limbal stem cell deficiency. We examined these reports to discern the success rate, complication rate, visual outcome, whether there is an optimal technique and which patients are the most likely to benefit. We also discuss the different culture methods employed and the regulations governing cell banks that are providing this service. We found that the techniques used to cultivate and transplant cells varied, but that no individual method was clearly superior. The reported success rate is similar across all studies for both allografts and autografts. The clinical indications for this treatment are not clearly defined as indicated by the variety of disorders treated. Follow-up is limited and the long-term success rate is yet to be established. Nonetheless, we conclude that there is sufficient evidence to support the continued use and refinement of this procedure as a treatment for corneal stem cell deficiency.

Significance of IgG4 in the diagnosis of mucous membrane pemphigoid

OBJECTIVE

To determine the diagnostic value and frequency of tissue deposition of IgG4 in comparison to polyclonal IgG, IgA, IgM, and C3.

STUDY DESIGN

Oral mucosal biopsies of 82 patients clinically suspected to have mucous membrane pemphigoid (MMP) were analyzed by direct immunofluorescence (IF) using polyclonal anti-human IgG, IgM, IgA, fibrin, complement C3, and anti-human IgG4 subclass monoclonal antibodies.

RESULTS

Based on clinical, hematoxylin and eosin (H & E), and direct IF studies, 34 cases were diagnosed as MMP. The most common antibody deposited was IgG (90%), followed by C3 (82%), and IgG4 (71%). In more than half the cases of MMP, IgG4 deposition was seen in combination with IgG and or C3. Strikingly, IgG4 was the sole antibody detected in 2 cases (6%).

CONCLUSION

Our results suggest that the use of monoclonal IgG4 is important in the diagnosis of MMP. We suggest adding monoclonal IgG4 to the routine panel of antibodies used in studies of cases suspected to have MMP to avoid false-negatives.

The Definition and Classification of Dry Eye Disease: Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop (2007)

The aim of the DEWS Definition and Classification Subcommittee was to provide a contemporary definition of dry eye disease, supported within a comprehensive classification framework. A new definition of dry eye was developed to reflect current understanding of the disease, and the committee recommended a three-part classification system. The first part is etiopathogenic and illustrates the multiple causes of dry eye. The second is mechanistic and shows how each cause of dry eye may act through a common pathway. It is stressed that any form of dry eye can interact with and exacerbate other forms of dry eye, as part of a vicious circle. Finally, a scheme is presented, based on the severity of the dry eye disease, which is expected to provide a rational basis for therapy. These guidelines are not intended to override the clinical assessment and judgment of an expert clinician in individual cases, but they should prove helpful in the conduct of clinical practice and research.

Application of topical mitomycin C to the base of shave-removed keloid scars to prevent their recurrence

BACKGROUND

Keloid scars are formed by over-activity of fibroblasts producing collagen and they cause significant morbidity both from their appearance and from their symptoms. Existing treatments are often unsatisfactory. Topical mitomycin C is known to inhibit fibroblast proliferation.

OBJECTIVES

To determine whether application of mitomycin C to the base of shave-removed keloids would prevent their recurrence.

METHODS

Ten patients had all or part of their keloid shave-removed. After haemostasis topical mitomycin C 1 mg mL(-1) was applied for 3 min. This application was repeated after 3 weeks. The keloids were photographed before treatment and the patients were reviewed every 2 months for a total of 6 months when a final photograph of the keloid site was taken. The patients and the Clinical Trials Unit staff scored the outcome on a linear analogue scale of 0-10, where 0 = disappointed and 10 = delighted. The pretreatment and 6-month post-treatment photographs were also assessed by two dermatologists who were not involved in the clinical trial.

RESULTS

Four of the 10 patients were delighted with the outcome of treatment and only one was disappointed. On average there was an 80% satisfied outcome.

CONCLUSIONS

This new treatment of keloids has been shown to be effective in the majority of patients but further studies are required to confirm this benefit.

Mitomycin: clinical applications in ophthalmic practice

Mitomycin (mitomycin C; MMC) is an antibiotic isolated from Streptomyces caespitosus. The drug is a bioreductive alkylating agent that undergoes metabolic reductive activation, and has various oxygen tension-dependent cytotoxic effects on cells, including the cross-linking of DNA. It is widely used systemically for the treatment of malignancies, and has gained popularity as topical adjunctive therapy in ocular and adnexal surgery over the past 2 decades. In ophthalmic medicine, it is principally used to inhibit the wound healing response and reduce scarring of surgically fashioned ostia. Hence, it has been used as adjunctive therapy in various ocular surgeries, such as glaucoma filtering surgeries, dacryocystorhinostomy, corneal refractive surgery and surgeries for ocular cicatrisation. In addition, it has been used as an adjunct in the surgical management of pterygia, ocular surface squamous neoplasia, primary acquired melanosis with atypia and conjunctival melanoma. In many of these surgeries and ophthalmic pathologies, MMC showed a significant beneficial effect.