Abstract
Lymphoid tissues from asymptomatic HIV-infected individuals, as
compared with symptomatic HIV-infected subjects, show limited
histopathological changes and lower levels of HIV expression. In this
report we correlate the control of HIV replication in lymph nodes to
the non-cytolytic anti-HIV activity of lymphoid tissue CD8
+
cells. Five subjects at different stages of HIV-related disease were
studied and the ability of their CD8
+
cells, isolated from
both lymphoid tissue and peripheral blood, to inhibit HIV replication
was compared. CD8
+
cells from lymphoid tissue and
peripheral blood of two HIV-infected long-term survivors suppressed HIV
replication at a low CD8
+
:CD4
+
cell ratio of
0.1. The CD8
+
cells from the lymphoid tissue of a third
asymptomatic subject suppressed HIV replication at a
CD8
+
:CD4
+
cell ratio of 0.25; the subject’s
peripheral blood CD8
+
cells showed this antiviral response
at a lower ratio of 0.05. The lymphoid tissue CD8
+
cells
from two AIDS patients were not able to suppress HIV replication, and
the peripheral blood CD8
+
cells of only one of them
suppressed HIV replication. The plasma viremia, cellular HIV load as
well as the extent of pathology and virus expression in the lymphoid
tissue of the two long-term survivors, were reduced compared with these
parameters in the three other subjects. The data suggest that the
extent of anti-HIV activity by CD8
+
cells from lymphoid
tissue relative to peripheral blood correlates best with the clinical
state measured by lymphoid tissue pathology and HIV burden in lymphoid
tissues and blood. The results add further emphasis to the importance
of this cellular immune response in controlling HIV pathogenesis.