IGHG3 and Parkinson disease: When Dwight German at the University of Texas Southwestern Medical Center, United States, and colleagues sought to validate these findings in serum samples from subjects in a larger longitudinal study of PD progression, they found no significant differences between the levels of PD2-bound IgG3 in newly diagnosed patients who had not yet begun taking medication and control subjects who did not show symptoms of PD over a 5-year period.