What is HIV?

HIV (human immunodeficiency virus) is an enveloped RNA retrovirus that attacks the immune system, depleting CD4+ T cells and progressively weakening the host response to infection. There are two types — HIV-1, which accounts for the vast majority of infections worldwide, and the less common, less transmissible HIV-2. Untreated, advanced infection progresses to AIDS (acquired immunodeficiency syndrome).

HIV is transmitted through blood and certain body fluids — including unprotected sex and shared needles. There is no cure, but antiretroviral therapy (ART) now allows people to reach an undetectable viral load and near-normal life expectancy. As of 2024, an estimated 40.8 million people were living with HIV globally, with 77% accessing treatment (UNAIDS).

ELISA is central to HIV detection — fourth-generation assays combine p24 antigen and HIV-1/2 antibody detection for earlier diagnosis. Beyond diagnosis, chronic immune activation in HIV drives changes in host biomarkers such as IL-6, IP-10, sCD14 and D-dimer that are widely studied as correlates of disease progression and comorbidity.

Transmission & symptoms

HIV (HIV-1 and HIV-2) is a retrovirus transmitted through blood and certain body fluids that depletes CD4+ T cells and progressively weakens immunity. Untreated infection progresses to AIDS; antiretroviral therapy now enables an undetectable viral load and near-normal life expectancy.

Diagnosis & serology

Fourth-generation ELISA combines p24 antigen with HIV-1/2 antibody detection for earlier diagnosis; confirmatory and viral-load testing follow. Host biomarkers of chronic immune activation are widely studied.

Research applications

Research tools cover HIV entry (the CD4 receptor with co-receptors CCR5 and CXCR4, and DC-SIGN capture) and immune-activation biomarkers (IL-6, IP-10, sCD14, D-dimer) linked to disease progression and comorbidity.