Based on the upregulation of CCL2, interleukin-17 receptor (IL17-R), and major histocompatibility complex (MHC) genes human leukocyte antigen B (HLA-B) and C (HLA-C) in senescent midbrain DA neurons (Riessland, 2020), it is plausible that the SASP of senescent midbrain DA neurons in PD patients triggers both an adaptive and innate immune response. Here, CCL2 is linked to Parkinson disease.