Reasons for immunologic inefficiency of antiretroviral therapy in patients with HIV

The main component of the treatment of patients with HIV infection is highly active antiretroviral therapy (HAART), which can help to control the disease. The main goal of HAART is to increase the life duration and to maintain the quality of patients’ life. Improved survival among HIV-infected patients receiving highly active antiretroviral therapy is achieved mainly by a decrease of HIV RNA viral load, which increases CD4 lymphocytes count. However, some patients may present with discordant response to treatment, when there is no CD4 lymphocyte count elevation associated with the virus disappearing from the blood. Such patients retain immunodeficiency, despite long-term treatment. The risk of opportunistic infections on the background of insufficient immunological response, despite viral replication suppression, is higher than in patients with good immunological response to treatment. Consistently low CD4 cell counts are associated with an increased risk of AIDS diagnosis. Furthermore, this group of patients shows a slight increase in mortality not associated with AIDS-defining illnesses. The reasons for the low CD4 lymphocytes count increase in some patients achieving virologic response to HAART remain unclear. The immunological efficacy of treatment depends on many factors: baseline CD4 count, duration of HIV infection prior to HAART initiation, age, co-infection with HCV, presence of secondary diseases and comorbidities, HAART regimens, IL-2 use and others. Literature review covers the phenomenon of immunological «non-response» to HAART, factors leading to its development, and possible methods of correction. Currently, there are more questions than answers in the area of immunological non-effectiveness of HAART in HIV-infected patients.