[Controversies in the association between type 1 diabetes and asthma].
OBJECTIVE
Critical review of the literature to investigate the relationship between asthma and type 1 diabetes mellitus (DM1).


METHODS
Bibliography search in MEDLINE and LILACS databases in the last twenty years.


METHODS
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.


CONCLUSIONS
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.
Alves
Crésio
C
Faculdade de Medicina, Universidade Federal da Bahia, Salvador, BA. cresio.alves@uol.com.br
Diniz
Andréa Borges
AB
Souza
Mateus Boaventura
MB
Ponte
Eduardo V
EV
Araújo
Maria Ilma
MI
D001249:Asthma / Q000150:complications* / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000235:genetics / Q000276:immunology; D006373:Helminthiasis / Q000150:complications / Q000276:immunology; D006801:Humans; D006920:Hygiene; D006969:Hypersensitivity, Immediate / Q000150:complications* / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D015415:Biomarkers; D016753:Interleukin-10