The Use of Leukapheresis to Support HIV Pathogenesis Studies

Despite the dramatic improvements that have resulted from combination antiretroviral treatment, long-term efficacy, toxicity, cost, and the requirements for life-long adherence remain as formidable challenges. Also, there is emerging consensus that persistent HIV-associated disease occurs during long-term highly active antiretroviral therapy (HAART). This disease may be due to either direct drug-toxicity and/or persistent viral replication/production and/or persistent HIV-associated inflammation. Hence, strategies aimed at achieving complete viral eradication may be needed in order to fully restore health among HIV infected individuals. Even if complete eradication proves impossible-as most believe to be the case-a less rigorous but still desirable outcome might be achieving durable control of virus in the absence of therapy. That a "functional" cure is possible is well illustrated by those rare individuals who are able to durably control replication competent virus in the absence of therapy ("elite" controllers).

A more complete understanding of the relationship between inflammation and viral persistence is necessary before more rationale studies of HIV eradication can be designed. Also, a well validated high through-put virologic assay needs to be developed that can estimate the size of the latent reservoir. Since the level of replication competent virus in long-term treated patients (and in elite controllers) is very small (< 1% of CD4 cells harbor HIV), large numbers of CD4+ T cells most be obtained from study participants in order to routinely isolate and quantify virus persistence.