Controvérsias na associação entre diabetes mellitus tipo 1 e asma

Abstract

RESUMOObjetivo: Revisão crítica da literatura sobre a associação entre asma e diabetes mellitus tipo 1 (DM1). Fonte dos dados: Pesquisa bibliográfica na base de dados MEDLINE e LILACS nos últimos vinte anos. Síntese dos dados: Muitos estudos mostram associação inversa entre asma, atopia e o risco de desenvolver DM1. De acordo com a "Hipótese da Higiene", o risco de doenças alérgicas diminui com infecções precoces na infância no sentido de afastar-se do perfil Th2, predominante ao nascimento, em direção ao fenótipo Th1. No entanto, outros trabalhos demonstram associação positiva ou ausência de associação entre DM1 e alergias. Existe a possibilidade de fatores ambientais contribuírem para ocorrência de doenças mediadas por células Th1 e Th2 no mesmo indivíduo, por provável deficiência de mecanismos imunomodulatórios mediados pela interleucina-10 e células regulatórias. Conclusão: As informações sobre a associação inversa entre doenças mediadas por resposta Th1 (por exemplo, DM1), e aquelas mediadas por resposta Th2 (por exemplo, alergias) são conflitantes, requerendo mais estudos para esclarecer esta questão. Objective: Critical review of the literature to investigate the relationship between asthma and type 1 diabetes mellitus (DM1). Source of data: Bibliography search in MEDLINE and LILACS databases in the last twenty years. Summary of data: Several studies demonstrate an inverse relationship between asthma, atopic diseases and the risk to develop DM1. According to the "Hygiene Hypothesis", the risk of allergic diseases decreases with infections early in childhood, towards distance of Th2 profile, common at birth, to the Th1 phenotype. Other articles described lack of association or positive association between DM1 and allergies. There is a possibility of environmental factors interfering in the development of disorders mediated by Th1 and Th2 cells, in the same individual, due to the absence of immunomodulatory mechanisms mediated by interleukin-10 and regulatory cells. Conclusion: The existing information about the inverse association between Th1-mediated diseases (e.g., DM1), and those that are Th2-mediated (e.g., allergies) are conflicting requiring more investigation to explain this question.

Type 1 Diabetes and Increased Risk of Subsequent Asthma

“… 23 The hygiene hypothesis provides an explanation for these complex associations and proposes that infections in early childhood may reduce the risk of allergic diseases and induce the Th2 profile to move toward the Th1 phenotype. 10 The decline of tuberculosis incidence could be related to rising rates of allergy and T1DM between tuberculin responses and atopic disorders in Japanese school children. 24 …”

“… 9 The hygiene hypothesis suggests that lower microbial exposure in early life may contribute to increased prevalence of immune-mediated diseases, such as asthma and T1DM. 10 , 11 The Th1 and Th2 secretory pattern of patients with T1DM and asthma combines features of both diseases, suggesting a unique Th1/Th2 balance, including a lower Th1/Th2 ratio compared with patients with T1DM only. 12 The relationship between asthma and T1DM among young people has not been thoroughly investigated.…”