Most commonly implicated in HIV-1 infection are the enzymes thioredoxin-1 (Trx1, TXN) and protein disulfide isomerase (PDI, PDIA1, P4HB), which share an enzymatic (thioredoxin-family) motif and many targets, initiating disulfide exchanges to modulate protein conformation (8). The gene discussed is P4HB; the disease is HIV-1 infection.