Autoantibodies in senear-usher syndrome: cross-reactivity or multiple autoimmunity?

A Recalcitrant Case of Senear-Usher Syndrome Treated With Rituximab

A 51-year-old uninsured, otherwise healthy male who works in the fishing industry presented with a two-month history of pruritic scaly plaques on his face, scalp, and trunk and mild photosensitivity. A biopsy of a scalp lesion revealed acantholysis consistent with pemphigus foliaceus. Laboratory testing demonstrated elevated anti-desmoglein 1, positive antinuclear antibodies (ANA and anti-dsDNA), and elevated Sjögren's anti-SS-A antibodies. The patient was diagnosed with pemphigus erythematosus. The patient was not optimally responsive and was unable to discontinue systemic corticosteroids despite a maximum dosage of mycophenolate mofetil of 3000 mg/day. Hence, rituximab was added as a rescue treatment with the rheumatoid arthritis protocol. Three months after starting rituximab, there was a marked improvement in symptoms with complete resolution of cutaneous lesions.

Autoimmune Pemphigus: Latest Advances and Emerging Therapies

Pemphigus represents a group of rare and severe autoimmune intra-epidermal blistering diseases affecting the skin and mucous membranes. These painful and debilitating diseases are driven by the production of autoantibodies that are mainly directed against the desmosomal adhesion proteins, desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1). The search to define underlying triggers for anti-Dsg-antibody production has revealed genetic, environmental, and possible vaccine-driven factors, but our knowledge of the processes underlying disease initiation and pathology remains incomplete. Recent studies point to an important role of T cells in supporting auto-antibody production; yet the involvement of the myeloid compartment remains unexplored. Clinical management of pemphigus is beginning to move away from broad-spectrum immunosuppression and towards B-cell-targeted therapies, which reduce many patients’ symptoms but can have significant side effects. Here, we review the latest developments in our understanding of the predisposing factors/conditions of pemphigus, the underlying pathogenic mechanisms, and new and emerging therapies to treat these devastating diseases.

Multiple autoimmunity and epitope spreading in monozygotic twins

We report clinical, serologic, and immunogenetic studies of a set of monozygotic male twin patients who develop autoimmune thyroiditis and vitiligo associated with the HLA-DRB1*04-DQB1*03:02 and HLA-DRB1*03-DQB1*0201 haplotypes. The patients had detectable anti-thyroid and anti-melanocyte autoantibodies. A critical review is presented regarding the role of MHC II molecules linked to clinical manifestations of various autoimmune diseases displayed in a single patient, as is the case in the twin patients reported here.

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Multiple autoimmunity is a clinicopathological issue that is not well understood.

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Monozygotic twins with thyroiditis, vitiligo, HLA-DRB1*04-DQB1*03:02 and HLA-DRB1*03-DQBI*0201 haplotypes.

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Multiple autoantibodies related with intermolecular epitope spreading. Epitope handling by MHC proteins probably related with multiple autoimmunity.

Genetics and Omics Analysis of Autoimmune Skin Blistering Diseases

Autoimmune blistering diseases (AIBDs) of the skin are characterized by autoantibodies against different intra-/extracellular structures within the epidermis and at the basement membrane zone (BMZ). Binding of the antibodies to their target antigen leads to inflammation at the respective binding site and degradation of these structures, resulting in the separation of the affected skin layers. Clinically, blistering, erythema and lesions of the skin and/or mucous membranes can be observed. Based on the localization of the autoantigen, AIBDs can be divided into pemphigus (intra-epidermal blistering diseases) and pemphigoid diseases (sub-epidermal blistering diseases), respectively. Although autoantigens have been extensively characterized, the underlying causes that trigger the diseases are still poorly understood. Besides the environment, genetic factors seem to play an important role in a predisposition to AIBDs. Here, we review currently known genetic and immunological mechanisms that contribute to the pathogenesis of AIBDs. Among the most commonly encountered genetic predispositions for AIBDs are the HLA gene region, and deleterious mutations of key genes for the immune system. Particularly, HLA class II genes such as the HLA-DR and HLA-DQ alleles have been shown to be prevalent in patients. This has prompted further epidemiological studies as well as unbiased Omics approaches on the transcriptome, microbiome, and proteome level to elucidate common and individual genetic risk factors as well as the molecular pathways that lead to the pathogenesis of AIBDs.

Serological Diagnosis of Autoimmune Bullous Skin Diseases

Autoimmune bullous dermatoses (AIBD) encompass a variety of organ-specific autoimmune diseases that manifest with cutaneous and/or mucosal blisters and erosions. They are characterized by autoantibodies targeting structural proteins of the skin, which are responsible for the intercellular contact between epidermal keratinocytes and for adhesion of the basal keratinocytes to the dermis. The autoantibodies disrupt the adhesive functions, leading to splitting and blister formation. In pemphigus diseases, blisters form intraepidermally, whereas in all other disease types they occur subepidermally. Early identification of autoimmune bullous dermatoses is crucial for both treatment and prognosis, particularly as regards tumor-associated disease entities. The diagnosis is based on clinical symptoms, histopathology, direct immunofluorescence to detect antibody/complement deposits, and the determination of circulating autoantibodies. The identification of various target antigens has paved the way for the recent development of numerous specific autoantibody tests. In particular, optimized designer antigens and multiplex test formats for indirect immunofluorescence and ELISA have enhanced and refined the laboratory analysis, enabling highly efficient serodiagnosis and follow-up. This review elaborates on the current standards in the serological diagnostics for autoimmune bullous dermatoses.

Autoantibodies to full body vascular cell junctions colocalize with MYZAP, ARVCF, desmoplakins I and II and p0071 in endemic pemphigus in Colombia, South America

BACKGROUND

We previously described a new variant of endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF).

METHODS

Here we aimed to investigate disease autoreactivity to vessels in all body organs/systems. We compared 57 patients and 57 controls from the endemic area, matched by demographics, age, sex, and work activity. We performed immunofluorescence, immunohistochemistry, confocal microscopy, immunoblotting, indirect immune electron microscopy studies, and autometallographic studies. We performed ultrasonography on large patient arteries, investigating for vascular anomalies. In addition, we reviewed autopsies on seven patients who died affected by El Bagre-EPF. We immunoadsorbed any positive vessel immunofluorescence with desmoglein (Dsg1), investigating for new autoantigens.

RESULTS

Overall, 57/57 patients affected by El Bagre-EPF displayed autoantibodies to vessels in all the organs/systems of the body via all methods (P < 0.01). The autoreactivity was polyclonal, and the patient's antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, ARVCF, and MYZAP (all from Progen Biotechnik, Germany; P < 0.01; all present at cell junctions). Immunoadsorption with Dsg1 on positive vessel immunofluorescence showed that the immune response against the vessels was directed against non-Dsg1 antigen(s). Autometallographic studies showed deposits of metals and metalloids in vessel cell junctions and in erythrocytes of 85% of patients (P < 0.01).

CONCLUSIONS

Immune response to these vascular antigens is likely altering endothelial cells and vessel shapes, thus disturbing hemodynamic flow. The flow alterations likely lead to inflammation and may play a role in the atherogenesis often seen in these patients.

Desmosomes in acquired disease

Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement integrates adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, which occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on the way in which human diseases can inform our understanding of basic desmosome biology and in turn, the means by which fundamental advances in the cell biology of desmosomes might lead to new treatments for acquired diseases of the desmosome.