Viral infections during early infancy, pregnancy and type 1 diabetes risk

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Type 1 diabetes (T1D) is a common autoimmune disease that mainly affects children and adolescents. Genetic factors contribute about 40% of the risk, but cannot explain the rising incidence or geographical differences of T1D, which must be attributed to un known environmental factors. The MIDIA project, which aims to discover these environmental factors, has recruited infants with high genetic risk for T1D and follows these with questionnaires, stool- and blood samples. Viruses are good candidates for envir onmental factors, as there are animal models of T1D that show both protection and higher risk by viral infections and certain viruses have been found to be more common in recent onset T1D patients. Also the lack of infections or maternal antibodies in ear ly infancy might be associated with development of autoimmunity. In this project we have already investigated in a nested case control 27 children who developed islet autoimmunity and 54 matched controls, and found a higher prevalence of human parechoviru s infections just before the onset of islet autoimmunity. The main goal of this project is to investigate the association between viral infections in early childhood or in pregnancy and T1D. The objectives are to test stool samples from children and blood samples from mothers for viruses and provide new data regarding what role they play in T1D. We want to investigate further our positive findings in a bigger material, and see if other viruses play a role in the development of autoimmunity. The main chall enges will be developing assays that are sensitive and specific enough for this purpose and the high amount of testing involved. The new knowledge may ultimately be used to devise prevention strategies, which will be of high value even if they prevent a f raction of the cases or delay the onset of T1D.