Ae. Sousa et Rmm. Victorino, SINGLE-CELL ANALYSIS OF LYMPHOKINE IMBALANCE IN ASYMPTOMATIC HIV-1 INFECTION - EVIDENCE FOR A MAJOR ALTERATION WITHIN THE CD8(-CELL SUBSET() T), Clinical and experimental immunology, 112(2), 1998, pp. 294-302
In this study we investigated at single-cell level by how cytometry th
e potential of T cell cytokine production in asymptomatic HIV-1-infect
ed subjects with > 200 CD4 counts and possible correlation with T help
er cell depletion and viral load. Mitogen-stimulated peripheral blood
mononuclear cells from 32 HIV-1(+) patients and 16 healthy subjects we
re intracytoplasmically stained for IL-2, interferon-gamma (IFN-gamma)
, IL-4 or IL-10, and the frequency of cytokine-producing cells was ass
essed in total T cells, CD4, CD8 and CD45RO subsets as well as in CD69
(+) CD3(+) gated lymphocytes. HIV-1(+) patients, irrespective of their
degree of CD4 depletion, exhibited a major increase in IFN-gamma(+) C
D8 T cells, largely due to CD28(-) cells, as well as a decrease in the
capacity of CD8 T cells to produce IL-2. Patients with > 500 CD4 coun
ts showed a diminished frequency of IL-4 expression in CD4 T cells and
a negative correlation was found between this parameter and the ex vi
vo CD4 counts in the 32 patients. Analysis of patients stratified acco
rding to viral load revealed a significantly higher proportion of IL-2
-producing CD4 cells in the group with < 5000 RNA copies/ml. In short,
using single-cell analysis and an antigen-presenting cell-independent
stimulus, we have not been able to find any significant cytokine imba
lances in the CD4 subset, suggesting that the well described T helper
defects are not due to intrinsic alterations in the potential of CD4 T
cells to produce cytokines. On the other hand, the major disturbances
in the CD8 T lymphocytes agree with the marked activation and possibl
e replicative senescence of CD8 T cells and emphasize the role of this
subset in HIV immunopathogenesis.