Can research at the end of life be a useful tool to advance HIV cure?

Abstract

OPINION Can research at the end of life be a useful tool to advance HIV cure? Sara Gianella a , Jeff Taylor b , Timothy R. Brown c , Andy Kaytes b , Cristian L. Achim a , David J. Moore a , Susan J. Little a , Ronald J. Ellis a and Davey M. Smith a,d AIDS 2017, 31:1–4 Keywords: end of life, eradication, HIV cure, last gift, legacy, peri-mortem research model, research Modern antiretroviral therapy (ART) has saved millions of years of life [1], but it cannot eradicate latently infected cells [2,3]. The replication-competent provirus that remains during ART represents the major barrier to curing HIV [4]. Most of this latent reservoir resides in solid tissues and not in circulating blood, and we have yet to fully define the sanctuary sites of HIV persistence [5]. Timothy Ray Brown (known by many as the ‘Berlin Patient’) may be the closest to an HIV cure after being treated with an allogeneic hematopoietic stem cell transplant from a donor who was homozygous for the CCR5D32 deletion [6]. Unfortunately, this remarkable success has not been reproduced, and robust viral replication resumes almost universally following treat- ment interruption [7–9]. Even if strategies currently in development succeed in purging HIV from circulating CD4 þ T cells, residual virus can remain in the central nervous system (CNS), gut-associated lymphoid tissue (GALT), genital tract, adipose tissue, and others [9–12]. Thus, cure efforts must tackle the eradication of HIV reservoirs in anatomic compartments and sanctuaries throughout the body. The earliest stages of HIV infection are characterized by high levels of viral replication and little immune response [13,14]. This window of uncontrolled replication allows the virus to seed reservoirs throughout the body, as early as within 2 weeks of HIV infection [15], and to persist indefinitely throughout the lifespan of HIV-infected individuals [10]. These proviral reservoirs continue to expand and diversify until viral replication is successfully suppressed with ART. Despite extensive investigations, we still do not fully understand the dynamics of the total body HIV reservoir and how sub-reservoirs in various compart- ments relate to one another. For example, it remains unclear what factors govern the size and the activity of replication-competent HIV DNA in the CNS compared to the genital tract and blood. Most studies that have explored nonblood reservoirs among persons living with HIV infection have been limited to small samples of cerebrospinal fluid (CSF), genital secretion, gut, and shallow lymph nodes [10,16]. Studies using macaque models with simian immunodeficiency viruses (SIVs) have been enlightening for reservoirs in different tissues [17–23], but while SIV shares a high degree of structural and sequence identity to HIV, studies of SIV will not suffice to test eradication strategies for humans. For example, the Merck adenovirus type 5 (Ad5) trivalent HIV-1 vaccine trial (STEP trial) did not show efficacy in preventing HIV infection or slowing disease progression [24], despite promising results in various macaques’ trials [25–27]. As the field tackles the ambitious goal of eradicating HIV from the human body, we will need to test the effectiveness of cure interventions in living persons. a University of California, San Diego, La Jolla, b Community Advisory Board (CAB) AntiViral Research Center (AVRC), c Las Vegas, Nevada, and d Veterans Affairs San Diego Healthcare System, San Diego, California, USA. Correspondence to Sara Gianella, University of California San Diego, 9500 Gilman Drive, MC 0679, La Jolla, CA 92093-0679, USA. Tel: +1 858 642 1620; fax: +1 858 552 7445; e-mail: gianella@ucsd.edu Received: 18 August 2016; revised: 23 September 2016; accepted: 27 September 2016. DOI:10.1097/QAD.0000000000001300 ISSN 0269-9370 Copyright Q 2016 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.