Cardiac autoantibodies from patients affected by a new variant of endemic pemphigus foliaceus in Colombia, South America

The M3 Muscarinic Acetylcholine Receptor Promotes Epidermal Differentiation

The M3 muscarinic acetylcholine receptor is predominantly expressed in the basal epidermal layer where it mediates the effects of the autocrine/paracrine cytotransmitter acetylcholine. Patients with the autoimmune blistering disease pemphigus develop autoantibodies to M3 muscarinic acetylcholine receptor and show alterations in keratinocyte adhesion, proliferation, and differentiation, suggesting that M3 muscarinic acetylcholine receptor controls these cellular functions. Chmr3^-/- mice display altered epidermal morphology resembling that seen in patients with pemphigus vulgaris. In this study, we characterized the cellular and molecular mechanisms through which M3 muscarinic acetylcholine receptor controls epidermal structure and function. We used single-cell RNA sequencing to evaluate keratinocyte heterogeneity and identify differentially expressed genes in specific subpopulations of epidermal cells in Chmr3^-/- neonatal mice. We found that Chmr3^-/- mice feature abnormal epidermal morphology characterized by accumulation of nucleated basal cells, shrinkage of basal keratinocytes, and enlargement of intercellular spaces. These morphologic changes were associated with upregulation of cell proliferation genes and downregulation of genes contributing to epidermal differentiation, extracellular matrix formation, intercellular adhesion, and cell arrangement. These findings provide, to our knowledge, previously unreported insights into how acetylcholine controls epidermal differentiation and lay a groundwork for future translational studies evaluating the therapeutic potential of cholinergic drugs in dermatology.

Patterns of Antinuclear Antibodies in a New Variant of Endemic Pemphigus in El Bagre, Colombia, Colocalizing with Antigens against MIZAP, ARVCF, p0071, and Desmoplakins I and II

BACKGROUND

A new variant of endemic pemphigus foliaceus (EPF) has been documented, El Bagre-EPF. We aimed to study antinuclear antibodies (ANAs) in these patients.

METHODS

We performed a case-control study, testing 57 patients affected by this disease and 57 controls from the endemic area matched by work activity and demographics. The participants were evaluated clinically as well as by detection of ANAs utilizing HEp-2 cells. We utilized Triton-induced partial permeabilization of the cell membranes, allowing for the visualization of intracellular and intranuclear antigens. We also immunoadsorbed the ANAs using synthetic peptides to elucidate the nature of the ANA.

RESULTS

We detected the presence of a new pattern of ANAs. The new pattern of ANAs was seen in 24% of the El Bagre-EPF patients, compared to our controls (P < 0.001). The new ANA pattern consisted of a thin nuclear and nucleolar rim, finely speckled nucleolar, nuclear membrane pores stains, and a positive intranuclear stain directed against small nuclear components, as well as cytoplasmic deposits of autoantibodies were also observed. The new ANAs pattern perfectly colocalized with commercial antibodies to miocardium-enriched zonula occlusans-1 associated protein (MIZAP), armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), p0071 and desmoplakins I-II (all from Progen Biotechnik). Additionally in 14% of patients with El Bagre-EPF forme fruste and hyperpigmented clinical presentations, a classic homogeneous ANA pattern was observed with autoantibodies specific for Ro, La, Sm, and double-stranded DNA antigens. Immunoadsorption with peptide-based sequences from MIZAP, ARVCF, p0071 and desmoplakins I-II removed the new ANA pattern.

CONCLUSIONS

We describe a new pattern of ANAs in El Bagre-EPF, colocalizing with autoantibodies directed against MIZAP, ARVCF, p0071, and desmoplakins I-II.

Pemphigus-associated cardiomyopathy: report of autoimmune myocarditis and review of literature

Pemphigus is a rare disease characterized by bullous lesions of the skin and mucous membranes. The aetiology is autoimmune and related to the formation of IgG autoantibodies against desmogleins, which are structural proteins of desmosomes that ensure the stability of contacts between cells. Cardiac involvement in patients with pemphigus is poorly documented. We report the data in the literature on this topic and a case of pemphigus-associated autoimmune myocarditis with damage of intercalated disc responding to immunosuppressive therapy. The occurrence of cardiomyopathy with left ventricular dysfunction in patients affected by pemphigus should be appropriately screened with endomyocardial biopsy as it could be the myocardial extension of a potentially reversible autoimmune disorder.

Cardiac function in pemphigus vulgaris patients before and after steroid pulse therapy

BACKGROUND

Pemphigus vulgaris which is an autoimmune dermatological disorder characterized by vesiculobullous lesions over the skin and mucosae may also give rise to cardiac disease. Global Longitudinal Strain (GLS) measurement may help to predict cardiac dysfunction in these patients.

METHOD

In this prospective study, the GLS was measured before and after steroid pulse therapy in pemphigus vulgaris patients using 2 D speckle-tracking echocardiography. Moreover, blood pressure, pulse rate, and corrected QT (cQT) interval were recorded before and after steroid pulse therapy.

RESULTS

We included 23 pemphigus patients. The mean age of patients was 34.5(±6.4). Mean GLS decreased significantly after the administration of steroid pulse therapy. The mean GLS decreased regardless of age, however, the patients with the age range of 40-50 years showed the highest change in GLS. There was no interaction between gender and GLS change. Mean cQT increased significantly after pulse therapy (p=.007). Heart rate increased significantly from 88.5 ± 10.8 to 97.0 ± 13.4 (p<.001). Mean systolic and diastolic blood pressure did not show any significant change.

CONCLUSIONS

The steroid pulse therapy may associate with the progression of cardiac dysfunction in pemphigus patients. GLS, as a predictor, may be a valuable marker of cardiac subclinical dysfunction in this condition.

Involvement of the Areae Compositae of the Heart in Endemic Pemphigus Foliaceus

Background

A new variant of endemic pemphigus foliaceus in El Bagre (El Bagre-EPF), Colombia, South America, shares features with Senear-Usher syndrome and occurs in an endemic fashion. Patients affected by El Bagre-EPF have heterogeneous antigenic reactivity not only to the skin but to other organs, including the heart. Here we test for autoantibodies to the areae compositae of the heart (structure consisting of typical desmosomal amalgamated fascia adherens molecules) and evaluate any possible clinical correlation.

Methods

A case-control study comparing 45 patients and 45 controls from the endemic area, matched by demographics including age, gender, weight, work activities, and comorbidities, was performed. Direct and indirect immunofluorescence, immunohistochemistry, confocal microscopic studies, and echocardiogram studies were completed.

Results

The main clinical abnormally seen in the El Bagre-EPF patients was left ventricular hypertrophy in 15/45 patients, compared with no such findings in the control population (P < 0.1). Seventy percent of El Bagre-EPF patients and none of the controls displayed polyclonal autoreactivity using different immunoglobulins and complement to the areae compositae of the heart using different methods and antibodies (P < 0.1).

Conclusions

Patients affected by El Bagre-EPF demonstrated autoantibodies to the areae compositae of the heart. This finding was associated with left ventricular hypertrophic cardiomyopathy. The areae compositae may play a role in cell junction tension and the El Bagre-EPF patients' autoantibodies possibly disrupting these junctions and thereby contributing to the left ventricular hypertrophy.

Patients affected by a new variant of endemic pemphigus foliaceus have autoantibodies colocalizing with MYZAP, p0071, desmoplakins 1-2 and ARVCF, causing renal damage

BACKGROUND

We have previously reported that about 30% of patients affected by a new variant of endemic pemphigus foliaceus (EPF) in El Bagre, Colombia (termed El Bagre-EPF or pemphigus Abreu-Manu) have systemic compromise. In the current study, we focused on studying autoreactivity to the kidney and its pathological correlations.

AIM

To investigate patients with El Bagre-EPF for renal compromise.

METHODS

We performed a case-control study, enrolling 57 patients with El Bagre-EPF and 57 controls from the endemic area, matched by age, sex, race, work activity, demographics and comorbidities. We took skin and renal biopsies; performed direct and indirect immunofluorescence, immunohistochemistry (IHC), confocal microscopy, immunoblotting, direct and indirect immune electron microscopy; and tested kidney function in all living patients. We also used IHC to study seven kidney autopsy samples.

RESULTS

Of the 57 patients, 19 had autoantibodies to kidney, with polyclonal reactivity (P < 0.01). Most cases were positive along the basement membrane of the proximal tubules, but in some cases there was also positivity against the glomeruli and/or mixed patterns. Fifteen patients had increases in serum urea and creatinine compared with controls (P < 0.01). The autoantibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARCVF) and myocardium-enriched zonula occludens-1-associated protein (MYZAP) (P < 0.01). All of the kidney disease autopsies showed alterations, mostly in the vessels.

CONCLUSION

We demonstrate for the first time that one-third of patients with El Bagre-EPF have polyclonal autoantibodies to kidney. The kidneys showed a mixed histological pattern resembling lupus nephritis, with a diffuse proliferative Class IV (G) global diffuse pattern in active lesions, and additional interposition of membranoproliferative glomerulonephritis.

Oxidative stress in patients with endemic pemphigus foliaceus and healthy subjects with anti-desmoglein 1 antibodies

BACKGROUND

Previous studies have shown oxidative stress in pemphigus vulgaris and pemphigus foliaceus, nevertheless, it remains unknown whether a similar response is characteristic of endemic pemphigus foliaceus in Peru.

OBJECTIVES

To determine the oxidative stress response in endemic pemphigus foliaceus patients and subjects with positive for anti-desmoglein1 antibodies (anti-dsg1) from endemic areas of Peru.

SUBJECTS AND METHODS

This is a cross-sectional study. The study population included 21 patients with Endemic Pemphigus foliaceus and 12 healthy subjects with anti-dsg1 antibodies from the Peruvian Amazon (Ucayali), as well as 30 healthy control subjects. Malondialdehyde, an indicator of lipid peroxidation by free radicals, was measured in serum.

RESULTS

We collected 21 cases of endemic pemphigus foliaceus, 15 of them with active chronic disease and 6 in clinical remission. Serum malondialdehyde values in patients with chronic active evolution and healthy subjects with anti-dsg1 antibodies were statistically higher than those of healthy controls (p<0.001). There was no significant difference between serum values of localized and generalized clinical forms.

STUDY LIMITATIONS

The main limitation of this present study is the small number of patients with endemic pemphigus and healthy subjects positive for desmoglein 1 antibodies.

CONCLUSIONS

The increased serum levels of malondialdehyde in patients with chronic active endemic pemphigus foliaceus and healthy subjects from endemic areas with anti-dsg1 antibodies may suggest a contribution of systemic lipid peroxidation in the pathogenesis of endemic pemphigus foliaceus.

Patients affected by endemic pemphigus foliaceus in Colombia, South America exhibit autoantibodies to optic nerve sheath envelope cell junctions

Background

The majority of the patients affected by a new variant of endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre EPF or pemphigus Abreu-Manu), have experienced vision problems; we have previously reported several ocular abnormalities.

Methods

Here, we aimed to investigate reactivity to optic nerves in these patients. We utilized bovine, rat and mouse optic nerves, and performed immunofluorescence and confocal microscopy to test for optical nerve autoreactivity. We tested 45 patients affected by this disease and 45 controls from the endemic area matched by age, sex and work activity.

Results

Overall, 37 of the 45 patient sera reacted to the optic nerve envelope that is composed of leptomeninges; the reactivity was polyclonal and present mostly at the cell junctions (P < 0.001). The immune response was directed against optic nerve sheath cell junctions and the vessels inside it, as well as other molecules inside the nerve. No control cases were positive. Of interest, all the patient autoantibodies co-localized with commercial antibodies to desmoplakins I–II, myocardium-enriched zonula occludens-1- associated protein (MYZAP), armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), and plakophilin-4 (p0071) from Progen Biotechnik (P < 0.001).

Conclusion

We conclude that the majority of the patients affected by pemphigus Abreu-Manu have autoantibodies to optic nerve sheath envelope cell junctions. These antibodies also co-localize with armadillo repeat gene deleted in velo-cardio-facial syndrome, p0071 and desmoplakins I–II. The clinical significance of our findings remains unknown.

Cardiac rhythm and pacemaking abnormalities in patients affected by endemic pemphigus in Colombia may be the result of deposition of autoantibodies, complement, fibrinogen, and other molecules

BACKGROUND

We previously showed that one-third of patients affected by endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF), display autoreactivity to the heart.

OBJECTIVE

The purpose of this study was to investigate rhythm disturbances with the presence of autoantibodies and correlate them with ECG changes in these patients.

METHODS

We performed a study comparing 30 patients and 30 controls from the endemic area, matched by demographics, including age, sex, weight, work activities, and comorbidities. ECG as well as direct and indirect immunofluorescence, immunohistochemistry, and confocal microscopic studies focusing on cardiac node abnormalities were performed. Autopsies of 7 patients also were reviewed.

RESULTS

The main ECG abnormalities seen in the El Bagre-EPF patients were sinus bradycardia (in one-half), followed by left bundle branch block, left posterior fascicular block, and left anterior fascicular block compared with the controls. One-third of the patients displayed polyclonal autoantibodies against the sinoatrial and/or AV nodes and the His bundle correlating with rhythm anomalies and delays in the cardiac conduction system (P <.01). The patient antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), and myocardium-enriched zonula occludens-1-associated protein (MYZAP; Progen Biotechnik) (P <.01).

CONCLUSION

One-third of the patients affected by El Bagre-EPF have rhythm abnormalities that slow the conduction of impulses in cardiac nodes and the cardiac conduction system. These abnormalities likely occur as a result of deposition of autoantibodies, complement, and other inflammatory molecules. We show for the first time that MYZAP is present in cardiac nodes.

Cell junction protein armadillo repeat gene deleted in velo-cardio-facial syndrome is expressed in the skin and colocalizes with autoantibodies of patients affected by a new variant of endemic pemphigus foliaceus in Colombia

Background

We previously described a new variant of endemic pemphigus foliaceus in El Bagre, Colombia, South America (El Bagre-EPF, or pemphigus Abreu-Manu). El Bagre-EPF differs from other types of EPF clinically, epidemiologically, immunologically and in its target antigens. We reported the presence of patient autoantibodies colocalizing with armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), a catenin cell junction protein colocalizing with El Bagre-EPF autoantibodies in the heart and within pilosebaceous units along their neurovascular supply routes. Here we investigate the presence of ARVCF in skin and its possibility as a cutaneous El Bagre-EPF antigen.

Methods

We used a case-control study, testing sera of 45 patients and 45 controls via direct and indirect immunofluorescence (DIF/IIF), confocal microscopy, immunoelectron microscopy and immunoblotting for the presence of ARVCF and its relationship with El Bagre-EPF autoantibodies in the skin. We also immunoadsorbed samples with desmoglein 1 (Dsg1) ectodomain (El Bagre-EPF antigen) by incubating with the positive ARVCF samples from DIF and IIF.

Results

ARVCF was expressed in all the samples from the cases and controls. Immunoadsorption with Dsg1 on positive ARVCF immunofluorescence DIF/IIF cases showed that the immune response was present against non-desmoglein 1 antigen(s). Overall, 40/45 patients showed colocalization of their autoantibodies with ARVCF in the epidermis; no controls from the endemic area displayed colocalization.

Conclusions

We demonstrate that ARVCF is expressed in many areas of human skin, and colocalizes with the majority of El Bagre-EPF autoantibodies as a putative antigen.

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.

Patients with a new variant of endemic pemphigus foliaceus have autoantibodies against arrector pili muscle, colocalizing with MYZAP, p0071, desmoplakins 1 and 2 and ARVCF

BACKGROUND

We identified a new variant of endemic pemphigus foliaceus in El Bagre, Colombia, South America, which we term El Bagre-EPF, and observed reactivity to arrector pili muscle (APM), thus we tested for autoimmunity to APM.

METHODS

We took skin biopsies from 30 patients with El Bagre-EPF and 30 healthy controls (HCs) matched by age, sex and occupation, who were all from the endemic area, and tested these using direct immunofluorescence (DIF), confocal microscopy, immunohistochemistry and immunoblotting (IB).

RESULTS

Of the 30 patients with El Bagre-EPF, 27 had autoantibodies to APM that colocalized with commercial antibodies to myocardium-enriched zonula occludens-1-associated protein (MYZAP), desmoplakin (DP)1 and DP2, plakophilin 4, and Armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF) (P < 0.001, Fisher exact test). The positive staining also colocalized with Junctional Adhesion Molecule 1 (JAM-A), a control antibody for gap cell junctions. No HC samples were positive. In 27 of the 30 patients, serum that was APM-positive also displayed IB colocalization of their autoantibody molecular weights with the Progen antibodies (P < 0.001, Fisher exact test).

CONCLUSIONS

Patients affected by El Bagre-EPF have autoantibodies to APM, colocalizing with the antibodies MYZAP, ARVCF, p0071, DP1 and DP2, suggesting that these molecules are El Bagre-EPF antigens. Further, all of these antigens represent components of cell junctions, indicating that the immune response is directed, at least partially, against cell junctions. The immune response in patients affected by El Bagre-EPF is polyclonal, and it includes B and T lymphocytes, mast cells, IgG, IgA, IgM, IgD, IgE, fibrinogen, albumin, complement/C1q, C3c and C4.

Prediction of survival for patients with pemphigus vulgaris and pemphigus foliaceus: a retrospective cohort study

Background

Factors associated with survival in pemphigus have not yet been thoroughly addressed. Therefore, in the present study, risk factors for overall mortality in a large group of patients with pemphigus vulgaris and foliaceus were investigated.

Methods

A retrospective hospital-based cohort study was carried out, between October 1998 and November 2012, in the Department of Dermatology of the University of Medicine and Pharmacy “Iuliu Hatieganu”, Cluj-Napoca, Romania. The investigated prognostic endpoint was the overall survival of the patients.

Results

A total of 130 patients were studied (108 with pemphigus vulgaris and 22 with pemphigus foliaceus). In pemphigus vulgaris group, univariate analysis found a statistically significant association between the age of onset ≥ 65 years (p < 0.001), presence of coronary heart disease (p = 0.006), presence of cardiac arrhythmia (p = 0.004), level of anti-desmoglein1 autoantibodies ≥ 100 U/mL (p = 0.047) at diagnosis and the survival of the patients. An age-adjusted analysis showed significant results for coronary heart disease. Multivariate analysis identified the age of onset ≥ 65 years and the presence of coronary heart disease at diagnosis as independent risk factors associated with overall mortality. In patients with pemphigus foliaceus, age of onset ≥ 65 years (p = 0.021) was associated with poor survival.

Conclusions

In addition to common prognostic factors, including older age and cardiovascular comorbidities, level of autoantibodies was found to be a disease-specific factor associated with overall mortality in pemphigus vulgaris. The newly identified factors have major implications for the stratification of patients and should greatly facilitate further epidemiological studies in pemphigus. In addition, they provide useful information for the design of personalized therapeutic plans in the clinical setting.

Autoimmunoreactive IgGs against cardiac lipid raft-associated proteins in patients with postural orthostatic tachycardia syndrome

Lipid rafts are specialized plasma membrane microdomains that serve as platforms for integrating cellular signal transductions. We have recently reported that autoantibodies against cardiac membrane proteins are present in patients with postural orthostatic tachycardia syndrome (POTS). In this study, we examined the presence of autoimmunoreactive IgGs against lipid raft proteins in these patients. IgGs were purified from the sera of 10 patients and 7 normal controls. Cardiac lipid raft preparations were isolated from normal human heart tissue. The lipid raft-associated proteins were resolved by 2-dimensional gel electrophoresis and immunoblotted against IgGs from each subject. Protein spots that reacted specifically with patient IgGs were identified by nano-liquid chromatography-mass spectrometry/mass spectrometry. Thirty-four such protein spots, and 72 unique proteins were identified. The targets of autoimmunoreactive IgGs include proteins associated with caveolae structure, adrenergic signaling, calcium signaling, cytostructures, chaperone and energy metabolism. Multiple pathways were involved including those that regulate caveolae-mediated signaling, oxidative phosphorylation, fatty acid metabolism, protein ubiquitination, and cardiac β-adrenergic signaling. Our results suggest that cardiac lipid raft-associated proteins are targets of autoimmunoreactive IgGs from patients with POTS. Autoimmunity may play a role in the pathogenesis of POTS.

Urban legends: pemphigus vulgaris

Pemphigus vulgaris (PV) is the most common type of pemphigus. PV pathogenesis is still debated, and treatment remains challenging. We investigated five controversial topics: (1) What are the target antigens in PV? (2) Do desmogleins adequately address PV pathophysiology? (3) How does acantholysis occur in PV? (4) Is PV still a lethal disease? (5) What is the role of rituximab (RTX) in PV treatment? Results from extensive literature searches suggested the following: (1) Target antigens of PV include a variety of molecules and receptors that are not physically compartmentalized within the epidermis. (2) PV is caused by a variety of autoantibodies to keratinocyte self-antigens, which concur to cause blistering by acting synergistically. (3) The concept of apoptolysis distinguishes the unique mechanism of autoantibody-induced keratinocyte damage in PV from other known forms of cell death. (4) PV remains potentially life-threatening largely because of treatment side effects, but it is uncertain which therapies carry the highest likelihood of lethal risk. (5) RTX is a very promising treatment option in patients with widespread recalcitrant or life-threatening PV. RTX's cost is an issue, its long-term side effects are still unknown, and randomized controlled trials are needed to establish the optimal dosing regimen.