A CD8(+) lymphocytic alveolitis occurs in up to 60% of asymptomatic human i
mmunodeficiency virus (HIV)-infected individuals. Early in HIV infection, l
ymphocytes consist predominantly of cytotoxic T lymphocytes directed agains
t HIV-infected targets. As HIV disease progresses, they are replaced by CD8
(+)CD57(+) suppressor cells. Virus-specific cytotoxic T lymphocytes secrete
interferon-gamma (IFN-gamma), an important cytokine in upregulating immune
responses, primarily through macrophage activation. We examined the abilit
y of lung and blood lymphocytes from HIV-positive patients at various stage
s of HIV infection to secrete IFN-gamma spontaneously and in response to ph
ytohemagglutinin A. IFN-gamma production and secretion were determined with
ELISA, Western blot, immunoprecipitation, and Northern blot techniques. Lu
ng lymphocytes from HIV-infected individuals secreted large amounts of IFN-
gamma. However, this ability was lost in patients with late-stage disease.
Correlation between blood and lung lymphocyte IFN-gamma secretion was poor,
suggesting regional differences in lymphocyte function. These data suggest
that lung levels of IFN-gamma are high until late in HIV disease. These fi
ndings support the concept of administering exogenous IFN-gamma to patients
with late-stage HIV disease and opportunistic infections.