Proviral load and immune function in blood and lymph node during HIV-1 and HIV-2 infection

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• Human Immunodeficiency Virus (HIV) infection affects immune cells, with varying impacts depending on the viral subtype (HIV-1 vs. HIV-2).
• Lymphadenopathy is a common clinical manifestation in HIV infection, suggesting involvement of lymphoid tissues.

Purpose of the Study:

• To compare proviral load, lymphocyte phenotype, and function in peripheral blood and lymph node compartments in patients with HIV-1, HIV-2, and dual infections.
• To investigate the implications of compartmental viral distribution and immune cell function on disease progression and susceptibility to opportunistic infections like tuberculosis.

Main Methods:

• Analysis of peripheral blood mononuclear cells (PBMC) and lymph node mononuclear cells (LNMC) from 17 HIV-1, 12 HIV-2, and 3 dually infected patients.
• Quantification of proviral load and assessment of CD4+ cell percentages in both compartments.
• Evaluation of lymphocyte proliferation and interferon-gamma (IFN-gamma) production in response to purified protein derivative (PPD).

Main Results:

• CD4+ cell percentages were significantly higher in LNMC compared to PBMC for both HIV-1 and HIV-2 infections.
• Adjusted proviral load was higher in LNMC than PBMC for both HIV types, with strong correlations between compartments.
• Lymphocyte responses (proliferation and IFN-gamma production) to PPD were lower in LNMC and PBMC compared to healthy controls, indicating impaired immune function.

Conclusions:

• HIV-1 and HIV-2 infected cells exhibit tropism for lymph nodes, leading to a higher viral burden in this compartment.
• Lower lymphocyte responses to recall antigens in lymphoid tissues may contribute to increased susceptibility to opportunistic infections, such as tuberculosis, in HIV-infected individuals.