Effective HAART suppresses HIV replication, and hence, viral load, resulting in increases in absolute CD4 T-cell counts. Typically, there are two phases in which T-cell counts rise: first, there is a rapid initial rise following effective HAART, followed by a slow, steady increase that may continue for years. Additionally, the loss of functional lymphocyte responses to many pathogen antigens can be reversed by HAART, although HIV-specific T-cell responses are not always reconstituted.¹

The thymus is the source of new T-cells. It was long believed that the thymus was damaged by HIV infection. However, a number of more recent studies have demonstrated that patients with untreated HIV infection do have active thymic tissue and the amount of thymic tissue that is present at the initiation of HAART correlates with the extent of the subsequent increase in CD4+ T-cells. Thus, the severity of IRS may be linked to the presence of functional thymic tissue at the initiation of therapy.

This month, Dr. Edward Gardner presents an overview of IRS for our readers and Courtney Colton presents a different perspective, reflecting on the difficulties that most patients (incarcerated or not) would have accessing HIV care in Mali. At the conclusion of this issue, readers should be more familiar with the epidemiology, diagnosis, and treatment of IRS, and should know when it is appropriate to initiate therapy in asymptomatic HIV-infected individuals. Lastly, readers should realize which treatment regimens are preferred and alternative.