TREM2 and neurodegenerative disease: Alteration of certain markers such as the triggering receptor expressed on myeloid cells 2 (TREM2) and the Colony Stimulating Factor-1 receptor (CSF-1R) correlates with neurodegenerative diseases (21) and leukodystrophy (22) respectively indicating the important role played by these cells in the homeostatic control of CNS.