The steep drop of the elevated α-synuclein-reactive antibody levels with age in DLB and AD may be due to absorption of antibodies by tissue-deposited α-synuclein and, in addition, pathophysiologically related to an accelerated immunosenescence with a disturbed T helper (Th) lymphocyte adaptive immunity [36]–[40]. Here, SNCA is linked to Lewy body dementia.