[1] Univ Pittsburgh, Sch Med, Dept Pathol, Inst Diabet,Rangos Res Ctr, Pittsburgh, PA 15213 USA
[2] Childrens Hosp Pittsburgh, Inst Diabet, Pittsburgh, PA USA
[3] Univ Pittsburgh, Sch Med, Dept Pediat, Div Immunogenet, Pittsburgh, PA 15261 USA
[4] Univ Palermo, Dept Biochem Sci, Palermo, Italy