CD4 and mitochondrial DNA depletion syndrome 4a: Early intervention is key, because AHD-related death can occur soon after initial presentation or re-engagement in care: among the REALITY trial cohort of PLHIV with CD4 cell count < 100 cells/μL, 12.7% died within 48 weeks of enrollment, with the highest mortality occurring during the first 4 weeks on ART [13].