[1] Univ Iowa, Stead Family Dept Pediat, Carver Coll Med, Iowa City, IA 52242 USA
[2] Univ Iowa, Immunol Grad Program, Iowa City, IA 52242 USA
[3] Univ Iowa, Iowa Inst Human Genet, Carver Coll Med, Iowa City, IA 52242 USA
[4] Med Coll Wisconsin, Dept Pediat, Milwaukee, WI 53226 USA
[5] Med Coll Wisconsin, Dept Microbiol & Immunol, Milwaukee, WI 53226 USA
[6] Med Coll Wisconsin, Max McGee Natl Res Ctr Juvenile Diabet, Milwaukee, WI 53226 USA