Immunological effects of antiretroviral therapy

The striking decline in HIV load with highly active antiretroviral combination therapy (HAART) is accompanied by substantial improvements in immune function, even in patients with more advanced disease. These include a general reduction in immune activation with increases in total CD4 and CD8 cell counts, memory and naive T cell subsets and antigen responses to certain opportunistic pathogens. At this time, it appears that HAART-induced improvements in function are limited to those T cells that have not yet been completely depleted by HIV. Long-term studies are needed to determine whether complete functional restoration of the repertoire is possible. Clinically, HAART improves survival and reduces progression of HIV disease. Some patients with active opportunistic disorders demonstrate complete or partial resolution of the infection or malignancy. However, persons with subclinical Mycobacterium avium complex or cytomegalovirus retinitis and those with chronic hepatitis B virus infection may sometimes experience acute flares if prophylactic therapy against the underlying disorder is not included in the regimen.