Abstract
We studied in vitro production of interferon-γ and expression of interferon-γ receptors (R1 and R2) by the peripheral blood mononuclear cells of 24 HIV-1-infected patients and 12 healthy volunteers. Interferon-γ production was lower in HIV-1-infected patients compared with healthy volunteers (p < 0.05), and it further declined in patients with lower CD4+ T-cell counts. In contrast, expression of interferon-γ R1 by CD4+ T lymphocytes was higher in HIV-infected patients than healthy volunteers (25% versus 10%, p < 0.05). In the HIV-infected group, interferon-γ R1 expression increased with a decline in CD4+ T-cell count (r = −0.64, p < 0.001). Interferon-γ R2 expression directly correlated with interferon-γ R1 expression (p < 0.001). When stimulated with heat-killed Mycobacterium avium complex (MAC) and phorbol myristic acetate (PMA), the mononuclear cells of patients with advanced HIV-1 infection had lowered ability to produce additional interferon-γ (either MAC or PMA) and interferon-γ receptors (MAC). In conclusion, with progression of HIV-1 infection, interferon-γ production declines whereas expression of interferon-γ receptors (R1 and R2) increases. Persistent upregulation of both interferon-γ R1 and R2 receptors probably favors development of type 2 T-helper cells environment and promotes viral replication. This dysfunction in the interferon-γ pathway contributes to a further impairment in cellular immune function in patients with advanced HIV-1 infection, which may further increase susceptibility to opportunistic infections.
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