Differences in mitochondrial activity in patients with sickle cell disease at steady state compared to patients experiencing acute pain. (A) Complex V and (B) complex IV activity in patients with sickle cell disease at steady-state (SS, no pain) compared with patients experiencing a moderate-to-severe VOE on the day of an ED visit. Compared with a cohort of SCD patients in SS, all VOE subjects had significantly decreased complex V activity; however, complex IV activities were similar in SS platelets vs VOE.