CD68 and amyotrophic lateral sclerosis: L-ferritin expression by CD68-expressing microglia has previously been reported in the deep layers of the ALS motor cortex [23], and the emergence here of a CD68high L-ferritinhigh microglial cluster in end-stage human ALS brain suggests that a pool of CD68high phagocytic microglia shift in late disease to an L-ferritinhigh dysfunctional state.