ABSTRACT
Abstract Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality in developed countries. Although cigarette smoking is the major risk factor, only 10-20% of smokers develop COPD. The extent of cigarette smoking (pack-years and smoking duration) accounts for only 15% of the variation in lung function, indicating that differences in susceptibility to COPD must exist. We provide an overview of the complexity of nicotine addiction and COPD, with special attention to the involvement of genetic factors. The following aspects are discussed in the present article: (1) epidemiology in Mexico and (2) a review of the published literature on genetic association studies using the National Center for Biotechnology Information database of the United States as a search tool. COPD is unique among complex genetic diseases where an environmental risk factor is known and the level of exposure can be documented with some precision. The high morbidity and mortality associated with COPD and its chronic and progressive nature has prompted the use of molecular genetic studies to identify susceptibility factors for the disease. Biomedical research has a remarkable set of tools to aid in the discovery of genes and polymorphisms. We present a review of the most relevant genetic associations in nicotine addiction and COPD.
Subject(s)
Humans , Tobacco Use Disorder/genetics , Genetic Predisposition to Disease , Pulmonary Disease, Chronic Obstructive/genetics , Tobacco Use Disorder/complications , Tobacco Use Disorder/epidemiology , Smoking/adverse effects , Smoking/genetics , Smoking/epidemiology , Risk Factors , Disease Progression , Pulmonary Disease, Chronic Obstructive/etiology , Pulmonary Disease, Chronic Obstructive/epidemiology , Mexico/epidemiology , Nicotine/administration & dosage , Nicotine/adverse effectsABSTRACT
Las enfermedades autoinmunes se caracterizan por inflamación, así como por el desarrollo y mantenimiento de anticuerpos y linfocitos T dirigidos contra antígenos propios (autoantígenos). Aunque la etiología de estas enfermedades es desconocida, poseen mecanismos en común. Existe una fuerte asociación genética entre ciertas enfermedades autoinmunes como la artritis reumatoide, esclerosis múltiple y diabetes mellitus insulino-dependiente y algunos alelos y/o haplotipos del complejo principal de histocompatibilidad. La explicación actual para este tipo de asociaciones propone que las moléculas del complejo principal de histocompatibilidad que se han encontrado asociadas, unen de manera eficiente autoantígenos envueltos en la patofisiología de la enfermedad, lo cual resulta en una respuesta inmune periférica mediada por células T contra autoantígenos y las secuelas autoinmunes. La susceptibilidad individual en autoinmunidad puede estar determinada por una combinación de polimorfismos específicos de genes que codifican para múltiples citocinas, antígenos del complejo principal de histocompatibilidad, moléculas de adhesión y proteínas celulares. Esta condición puede conducir a la expresión anormal de moléculas inmunorreguladoras y finalmente resultar en el desarrollo o exacerbación de la enfermedad. Recientemente también se ha estudiado el papel de las secuencias virales en la patogénesis de autoinmunidad, principalmente involucradas en mimetismo molecular.
Autoimmune diseases are characterized by inflammation and by the development and maintenance of antibodies and T lymphocytes against "self" antigens. Although the etiology of these diseases is unknown, they have a number of cellular and molecular mechanisms in common. A strong genetic association exists between a number of autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, and insulin-dependent diabetes mellitus (IDDM) and the expression of certain alleles or haplotypes of the major histocompatibility complex (MHC). The current explanation for this association proposes that disease-associated MHC molecules efficiently bind autoantigens involved in the pathophysiology of the disease. This results in a peripheral T cell-mediated immune response to the autoantigens and autoimmune sequelae. Individual susceptibility to autoimmune diseases may be determined by a combination of specific polymorphisms of genes encoding multiple cytokines, MHC antigens, adhesion molecules, and cellular proteins. This condition may lead to abnormal expression of immunoregulatory molecules and finally result in the development or exacerbation of the disease. Recently, the role of viral sequences in the pathogenesis of autoimmunity has been discussed, mainly involved in molecular mimicry.