Knox and Carrigan found that every AIDS patient had active replication of HHV-6A in every stage of AIDS, from their diagnosis to their autopsies, with many having CD4+ cell counts over 700. With HHV-6A, there were none of the bewildering questions about how a seemingly benign retrovirus could possibly cause all that carnage. “It’s also much more destructive. . . . It kills very well, and it destroys tissue very well. It can infect the brain, the lungs, the lymphoid organs, and the bone marrow.”