Non-infectious environmental antigens as a trigger for the initiation of an autoimmune skin disease.

Pemphigus represents a group of organ specific autoimmune blistering disorders of the skin mediated by pathogenic autoantibodies with well-defined antigenic targets. While most of these diseases are sporadic, endemic forms of disease do exist. The endemic form of pemphigus foliaceus (also known as fogo selvagem, FS) exhibits epidemiological features that suggest exposure to hematophagous insect bites are a possible precipitating factor of this autoimmune disease, and provides a unique opportunity to study how environmental factors contribute to autoimmune disease development. FS patients and healthy individuals from endemic regions show an autoreactive IgM response that starts in early childhood and becomes restricted to IgG4 autoantibodies in FS patients. In searching for triggering environmental antigens, we have found that IgG4 and IgE autoantibodies from FS patients cross-react with a salivary antigen from sand flies. The presence of these cross-reactive antibodies and antibody genetic analysis confirming that these antibodies evolve from the same naïve B cells provides compelling evidence that this non-infectious environmental antigen could be the initial target of the autoantibody response in FS. Consequently, FS serves as an ideal model to study the impact of environmental antigens in the development of autoimmune disease.

Overlapping IgG4 Responses to Self- and Environmental Antigens in Endemic Pemphigus Foliaceus.

The etiology of human autoimmune diseases in general remains largely unknown, although the genetic and environmental interplay may be relevant. This applies to the autoimmune diseases of the skin such as the pemphigus phenotypes and others. In this group, there is an endemic form of pemphigus foliaceus (also known as fogo selvagem [FS]) in which the pathogenic IgG4 autoantibody response to the self-antigen desmoglein 1 (Dsg1) cross-reacts with the LJM11 sand fly salivary gland Ag. In this investigation, we dissected the IgG4 autoantibody repertoires used by FS patients in response to endogenous self-Dsg1 and exogenous LJM11 sand fly Ag. Based on analyses of the genetic clonal signatures of these Abs, our results indicate that there is a significant overlap between these two responses, as all identified IgG4 mAbs cross-react to both Dsg1 and LJM11 Ags. Germline H- and L-chain V gene Abs generated according to mutated cross-reactive mAbs preserved their reactivity to both Ags. Our findings suggest that both Dsg1 autoantigen and LJM11 environmental Ag could be the initial antigenic stimulants for the IgG4 autoimmune responses in FS. These results support our hypothesis that LJM11 Ag plays a substantial role in triggering the IgG4 autoantibody development in FS and provide new insights on how noninfectious environmental Ag(s) may drive the generation of autoantibodies in IgG4-related autoimmune diseases.

Diabetes mellitus in patients with Alzheimer's disease: clinical description and correlation with the APOE genotype in a sample population from the province of Antioquia, Colombia.

INTRODUCTION: Alzheimer's disease is a multifactorial disease affecting approximately twenty million people worldwide. Numerous variables are associated with increased risk of developing this severe neurological disorder. Among the risk factors, diabetes mellitus, and the ε4 isoform of the APOE gene have been amply demonstrated as increasing the risk of developing this disease. OBJECTIVE: To determine if a correlation exists between APOE genotype, diabetes mellitus and Alzheimer's disease. MATERIALS AND METHODS: Clinical studies were carried out by surveying the clinical histories in a group of patients in the province of Antioquia, Colombia. Forty-three Alzheimer's patients were compared with 43 control subjects, paired by age and gender. Commercially available methods were used to determine whether the patients had diabetes, and restriction enzyme-based genotyping was used to determine the APOE genotypes. RESULTS: The most common non-neurological comorbidities were: arterial hypertension, acute myocardial infarction, chronic obstructive pulmonary disease and hypothyroidism. From the many variables investigated, two were conclusive: (1) the presence of Alzheimer's disease was higher in patients with diabetes mellitus, and (2) no correlation between late-onset sporadic Alzheimer's disease and APOE was found in the target population. CONCLUSIONS: To detect any association with the APOE genotype, a study involving much a larger population samples must be undertaken.

Cutting Edge: Brazilian pemphigus foliaceus anti-desmoglein 1 autoantibodies cross-react with sand fly salivary LJM11 antigen.

The environmental factors that contribute to the development of autoimmune diseases are largely unknown. Endemic pemphigus foliaceus in humans, known as Fogo Selvagem (FS) in Brazil, is mediated by pathogenic IgG4 autoantibodies against desmoglein 1 (Dsg1). Clusters of FS overlap with those of leishmaniasis, a disease transmitted by sand fly (Lutzomyia longipalpis) bites. In this study, we show that salivary Ags from the sand fly, and specifically the LJM11 salivary protein, are recognized by FS Abs. Anti-Dsg1 monoclonal autoantibodies derived from FS patients also cross-react with LJM11. Mice immunized with LJM11 generate anti-Dsg1 Abs. Thus, insect bites may deliver salivary Ags that initiate a cross-reactive IgG4 Ab response in genetically susceptible individuals and lead to subsequent FS. Our findings establish a clear relationship between an environmental, noninfectious Ag and the development of potentially pathogenic autoantibodies in an autoimmune disease.

Diabetes mellitus in patients withAlzheimer´s disease: clinical descriptionand correlation with the APOEgenotype in a sample population from the province of Antioquia, Colombia / Diabetes mellitus en pacientes con enfermedad de Alzheimer: descripción clínica y correlación con el genotipo APOE en una muestra de población del departamento de Antioquia, Colombia

Introduction. Alzheimer´s disease is a multifactorial disease affecting approximately twenty million people worldwide. Numerous variables are associated with increased risk of developing this severe neurological disorder. Among the risk factors, diabetes mellitus, and the ε4 isoform of the APOE gene have been amply demonstrated as increasing the risk of developing this disease. Objective. To determine if a correlation exists between APOE genotype, diabetes mellitus and Alzheimer´s disease. Materials and methods. Clinical studies were carried out by surveying the clinical histories in a group of patients in the province of Antioquia, Colombia. Forty-three Alzheimer´s patients were compared with 43 control subjects, paired by age and gender. Commercially available methods were used to determine whether the patients had diabetes, and restriction enzyme-based genotyping was used to determine the APOE genotypes. Results. The most common non-neurological comorbidities were: arterial hypertension, acute myocardial infarction, chronic obstructive pulmonary disease and hypothyroidism. From the many variables investigated, two were conclusive: (1) the presence of Alzheimer´s disease was higher in patients with diabetes mellitus, and (2) no correlation between late-onset sporadic Alzheimer´s disease and APOE was found in the target population. Conclusions. To detect any association with the APOE genotype, a study involving much a larger population samples must be undertaken.

Introducción. La enfermedad de Alzheimer es compleja y afecta, aproximadamente, a 20 millones de personas en todo el mundo. Muchas variables parecen aumentar el riesgo de desarrollar esta alteración neurológica. Entre los factores de riesgo, se ha demostrado ampliamente que la diabetes mellitus y la isoforma ε4 del gen APOE tienen incidencia positiva en el desarrollo de la enfermedad. Se reporta un estudio en el cual se investigó la posible correlación entre APOE, diabetes mellitus y la enfermedad de Alzheimer, en un grupo específico de pacientes del departamento de Antioquia, Colombia. Objetivo. Determinar si existe una correlación entre APOE, diabetes mellitus y la enfermedad de Alzheimer, en un grupo de pacientes de Antioquia, Colombia. Materiales y métodos. Se buscaron y analizaron las historias clínicas de los pacientes con diagnóstico de enfermedad de Alzheimer. Se seleccionaron aquellos que cumplían los criterios de inclusión. Se utilizaron métodos comercialmente disponibles para confirmar la presencia de diabetes mellitus. La genotipificación de APOE se hizo con un método basado en la PCR y la digestión con enzimas de restricción, en muestras de todos los participantes en el estudio. Resultados. En este estudio se analizan 43 casos de enfermedad de Alzheimer y 43 individuos sanos controles, pareados por edad y sexo. Las enfermedades concomitantes no neurológicas más comunes fueron: hipertensión arterial, infarto agudo del miocardio, enfermedad pulmonar obstructiva crónica e hipotiroidismo. Conclusiones. De las diferentes variables investigadas, dos arrojaron resultados concluyentes: i) la presencia de la enfermedad de Alzheimer es más frecuente en pacientes con diabetes mellitus, y 2) no se encontró correlación entre la enfermedad de Alzheimer de inicio tardío esporádico y el genotipo de APOE. Es importante indicar que debe llevarse a cabo un estudio con un tamaño de población mayor, para determinar cualquier posible correlación o inferencia con el genotipo de APOE.

Analysis of proteins using DIGE and MALDI mass spectrometry.

Difference gel electrophoresis (DIGE) is a common technique for characterizing differential protein expression in quantitative proteomics. Usually a combination of enzymatic digestion and peptide analysis by mass spectrometry is used to identify differentially expressed proteins following separation and statistical analysis by DIGE. In this chapter, methods for gel spot picking, enzymatic digestion, and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) for protein identification of DIGE-analyzed proteins are discussed. Two examples are given: first, a specific protein is used to test the sensitivity of the 2D DIGE/MALDI MS combination for protein quantification and identification, and second, several proteins with and without the labels typically used in DIGE are identified to demonstrate that these labels do not alter MS-based protein identification. Technical variations of protein gel spot preparation, in-gel digestion, and mass spectral protein identification are discussed.

Analysis of protein posttranslational modifications using DIGE-based proteomics.

Difference gel electrophoresis (DIGE) is most often used to assess relative changes in the expression levels of individual proteins in multiple complex samples, and this information is valuable in making inferences about relative protein activity. However, a protein's activity is not solely dependent upon its expression level. A change in activity may also be influenced by myriad posttranslational modifications (PTMs), including palmitoylation, ubiquitination, oxidation, and phosphorylation. In this chapter, we describe the use of DIGE to determine specific PTMs by introducing specific labels or changes in pI and/or molecular weight.