Is there a link between influenza and type I diabetes? Increased incidence of TID during the pandemic H1N1 influenza of 2009 in Chile.

Pandemic H1N1 2009 had the highest incidence in the middle-high income area of Santiago and affected mostly school age patients. Influenza A virus (IAVs) causes systemic and most commonly non-systemic infection. Interestingly, it is able to replicate only in the presence of trypsin-like enzymes, as lung and pancreas. IAVs infection may trigger beta cell destruction and increase the incidence of T1DM. A retrospective observational study of new T1DM pediatric patients from database of Clinica Las Condes between 1995 and 2012. From 58 patients, 44.7% were diagnosed between 2009 and 2010, coincident with the H1N1 virus outbreak. There were no differences in clinical neither metabolic parameters between those patients from the 2009-2010 period and the rest. From those patients with available antibody panel, it was negative in 30% of the 2009-2010 group vs. 12.5% of the rest of the cohort (p < 0.05). Only one 5.8 year old boy had history of H1N1 virus infection three months prior to the DM1 onset with negative antibodies. The temporal coincidence suggests a possible link between T1DM and H1N1 virus, might be thought to be through direct cytopathic damage. Unfortunately we could only confirm H1N1 previous infection in only one case. Prospective studies in new T1DM cases are necessary to test this hypothesis.