IGLV3-13 and Parkinson disease: Similarly, Jiang R. et al. (2019) isolated EV proteins from the serum of PD patients, and observed that the expression of afamin, apolipoprotein D and J, and pigmented epithelium-derived factor, were prominently increased, whereas the levels of complement C1q and protein Immunoglobulin Lambda Variable 1-33 (IGLV1-33) Cluster -33 were decreased in PD patients (Jiang R. et al., 2019).