Résumé
Introducción: El desarrollo de la tolerancia inmunológica frente a los autoantígenos se denomina autotolerancia. La Diabetes Mellitus tipo 1A (1ADM) es un trastorno metabólico secundario a la destrucción autoinmune de las células beta pancreáticas e insulitis. La miastenia grave (MG) es una enfermedad autoinmune causada por el bloqueo postsináptico de la placa mioneural por AAcs contra los receptores de acetilcolina (ACRA) o contra moléculas de la membrana postsináptica. La asociación entre DM1A y MG se puede observar en el síndrome poliglandular tipo III, caracterizado por enfermedad autoinmune de la glándula tiroides asociada con otras entidades autoinmunes. Método: Reporte de Casos, cuatro pacientes entre 7-19 años, con asociación de MG y DM1A atendidos en el Hospital Garrahan. Conclusión: La Tiroiditis de Hashimoto y la Enfermedad Celíaca son las enfermedades autoinmunes relacionadas más frecuentemente con DM1A en nuestra población. La bibliografía describe la asociación de MG y Tiroiditis de Hashimoto y su coexistencia con DM1A se describe en el Síndrome Poliglandular III. En este trabajo presentamos 4 casos de DM1A asociado con MG fuera de dicho síndrome (AU)
Introduction: The development of immune tolerance to autoantibodies (AAbs) is referred to as self-tolerance. Type 1A Diabetes Mellitus (1ADM) is a metabolic disorder secondary to autoimmune destruction of pancreatic beta cells and insulitis. Myasthenia gravis (MG) is an autoimmune disease caused by postsynaptic blockade of the myoneural plate by AAbs against acetylcholine receptors (Acra) or against postsynaptic membrane molecules. The association between 1ADM and MG may be observed in polyglandular syndrome type III, characterized by autoimmune disease of the thyroid associated with other autoimmune conditions. Methods: Case report; four patients between 7-19 years old, with an association of MG and 1ADM seen at the Garrahan Hospital. Conclusion: Hashimoto's thyroiditis and celiac disease are autoimmune diseases most frequently related to 1ADM in our population. In the literature, the association of MG and Hashimoto's thyroiditis has been described and its coexistence with 1ADM is reported in polyglandular syndrome III. In this study we present 4 cases of 1ADM associated with MG unrelated to this syndrome. (AU)
Sujets)
Humains , Enfant , Adolescent , Maladies auto-immunes , Polyendocrinopathies auto-immunes/diagnostic , Diabète de type 1/complications , Myasthénie/complications , Maladie chronique , Études transversalesRésumé
O diabetes melito tipo 1 auto-imune (DM1A) resulta da destruição auto-imune seletiva das células-beta pancreáticas produtoras de insulina. O principal determinante genético de suscetibilidade para o DM1A está em genes do complexo principal de histocompatibilidade, no cromossomo 6p211.3 (locus IDDM1), responsável por 40 por cento ou mais da agregação familiar dessa doença. O maior risco é conferido pelo genótipo do antígeno leucocitário humano HLA-DR3-DQA1* 0501-DQB1*0201/DR4-DQA1*0301-QB1*0302, e o haplótipo HLA-DR15-DQA1* 0102-DQB1*0602 é associado à proteção. Três outros loci relacionados à predisposição a DM1A são o número variável de freqüências repetidas (VNTR) do gene da insulina (IDDM2), que confere 10 por cento da suscetibilidade genética, o antígeno-4 associado ao linfócito T citotóxico (CTLA-4) e o protein tyrosine phosphatasis nonreceptor-type 22 (PTPN22). Muitos outros genes suspeitos de predispor à auto-imunidade estão sendo investigados. O DM1A é freqüentemente associado com doença auto-imune tiroidiana, doença celíaca, doença de Addison e várias outras doenças auto-imunes, caracterizadas por auto-anticorpos órgãos-específicos, relacionados aos mesmos determinantes genéticos. Esses anticorpos são úteis na detecção de auto-imunidade órgão-específica antes do aparecimento da doença clínica, prevenindo comorbidades.
Type 1 A diabetes mellitus (T1AD) results from the autoimmune destruction of the insulin producing pancreatic beta-cells. The largest contribution to genetic susceptibility comes from several genes located in the major histocompatibility complex on chromosome 6p21.3 (IDDM1 locus), accounting for at least 40 percent of the family aggregation of this disease. The highest-risk human leukocyte antigen HLA genotype for T1AD is DR3-DQA1*0501-DQB1*0201/DR4-DQA1*0301-DQB1*0302, whereas -DR15-DQA1*0102-DQB1*0602 haplotype is associated with dominant protection. Three other T1D loci associated with predisposition are the Variable Number for Tandem Repeats (VNTR) near the insulin gene (IDDM2), which accounts to 10 percent of genetic susceptibility, the Cytotoxic T-Lymphocyte-associated Antigen (CTLA-4)(IDDM 12) and the Protein Tyrosine Phosphatasis Nonreceptor-type 22 (PTPN22). Many other gene suspected to predispose to autoimmunity have been investigated. T1AD is frequently associated with autoimmune thyroid disease, celiac disase, Addison´s disease and many other autoimmune diseases, characterized by organ-specific autoantibodies and related to the same genetic background. Using these autoantibodies, organ specific autoimmunity may be detected before the development of clinical disease preventing significant morbidity.