Association between HIV-specific T helper responses and CTL activities in pediatric AIDS

Area of Science:

• Immunology
• Virology
• Pediatrics

Background:

• Perinatal HIV infection impacts T helper (Th) cell responses and cytotoxic T lymphocyte (CTL) activity.
• Disease progression in children with HIV is influenced by the profile of immune responses.

Purpose of the Study:

• To investigate the relationship between HIV-specific Th cell responses, CTL activity, viral load, and CD4(+) T cell counts in children with perinatal HIV infection.
• To understand how immune profiles correlate with disease progression rates.

Main Methods:

• Longitudinal studies were conducted on children with perinatal HIV infection.
• Analysis of HIV-specific Th cell responses (Th0, Th1, Th2), CTL activity, viral load, CD4(+) T cell counts, IL-2, IFN-gamma, IL-4, and beta-chemokine levels.
• Peripheral blood mononuclear cells were stimulated with envelope (env) peptides.

Main Results:

• Patients with AIDS showed low/undetectable HIV-specific Th and CTL activities, predominantly Th0 responses with low IFN-gamma and IL-4.
• Children with slow disease progression had increased IL-2 expression, more CD45RO(+) memory T cells, and higher proportions of Th1 clones.
• High env peptide-specific IL-2 correlated with increased HIV-specific CTL responses; delayed CTL activity was linked to lower IL-2 and elevated Th2 responses.
• Slowly progressing patients produced higher beta-chemokine levels than those with AIDS.

Conclusions:

• Impaired development of HIV-specific cellular responses and inhibited T cell differentiation in infancy are associated with rapid disease progression.
• Noncytotoxic antiviral activity may play a protective role, complementing HIV-specific CTL responses in children with slow disease progression.