Passive transfer of scrub typhus plasma to patients with AIDS: a descriptive clinical study

We examined the HIV-inhibitory effects previously found to be associated wi th scrub typhus infection. Individual 500 nil units of plasma from donors w ith mild scrub typhus were safety-tested, subjected to virucidal heat treat ment, and administered to 10 HIV-1-infected recipients who were not receivi ng antiretroviral drugs. HIV-1 copy number fell threefold or more in two re cipients, and virus burden was reduced for 8 weeks in 70% (7/10) of recipie nts of a single plasma infusion, compared with the mean of three pre-infusi on measurements. Scrub typhus donor plasma inhibited HIV-1 in vitro compare d with normal human plasma and media controls. in the clearest in vivo resp onse, reduction in viral load was accompanied by clinical improvement, a sw itchback from the syncytia-inducing to the non-syncytia-inducing phenotype, and decreases in CD8 cells and IL-6 levels. Scrub typhus infections can ge nerate heat-stable, transferable plasma factors that exert prolonged anti-H IV effects. Whether variability in the results is due to different scrub ty phus infections, different HIV infections or different individual responses , is unclear.