作者单位:Mayo Sch Grad Med Educ, Endocrine Res Unit, 200 First St SW, Rochester, MN 55905 USA[1]Mayo Clin, Lab Med & Pathol, 200 First St SW, Rochester, MN 55905 USA[2]Dept Neurol, 200 First St SW, Rochester, MN 55905 USA[3]Immunochem Lab, 200 First St SW, Rochester, MN 55905 USA[4]