LRRK2 and Parkinson disease: The regulation of LRRK2 expression in specific immune cell sub-types is unclear, however, it is known that specific pro-inflammatory mediators, such as IFN-γ, can induce expression of LRRK2 (Gardet et al., 2010); thus, the increased levels of LRRK2 in specific immune cells may be linked to elevated peripheral inflammation, which may or may not be associated with PD (e.g., Dzamko, 2017).