CD34 and Parkinson disease: Especially in the case of PD where gait and locomotor abnormalities have been well-characterized in prior rodent models these can now be fully explored in the context of human T cell functions and immune tolerance [170, 184–187]. While motor deficits in the humanized CD34 + mice have been described behavioral comparisons between established rodent models and humanized models await future studies in these exciting models reflective a broad range of human infectious and degenerative diseases [186].