The Benefits of Early Antiretroviral Therapy for HIV Infection: How Early is Early Enough?

Abstract

The case of the “Berlin Patient” is well-known. In 2007, an HIV-infected adult with leukemia underwent allogeneic hematopoietic stem cell transplant and was cured of his cancer (Hutter et al., 2009). As the donor was homozygous for the CCR5Δ32 deletion (which makes CD4+ T cells difficult to infect with HIV), the repopulated immune system lacked any detectable HIV and the patient has been apparently been cured. Two subsequent allogeneic transplants performed under potent ART (which protected the donor cells from de novo infection) resulted in a dramatic reduction in the frequency of cells harboring replication-competent HIV (generally referred to as the HIV “reservoir”) (Henrich et al., 2014). This was not enough to cure these two patients, however, as both individuals experienced a delayed but robust rebound in viremia after stopping therapy. A true cure will likely require complete eradication of the entire reservoir of HIV. This is a formidable challenge.