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Session 129
Poster Abstracts Immunological Factors in HIV-Infected Infants, Children, and Adolescents Wednesday, 1:30 - 3:30 pm Hall B |
Background: There is a need for better immune markers to
guide clinical decisions in managing HIV-infected children. Interleukin (IL)-7
is vital for differentiation and maintenance of memory CD8+ T cells,
which in turn are critical for controlling HIV. We hypothesized that CD8+
T-cell expression of IL-7 receptor (CD127) is lower in children with more
advanced HIV disease. This has been suggested by preliminary findings in adults
with HIV infection. Our aim was to determine if CD127 expression on CD8+
T cells could be used as a marker of HIV disease status and virologic control
in infected children.
Methods: In a cross-sectional evaluation, we used flow
cytometry to measure CD127 expression on CD8+ T cells of whole blood
from HIV-infected children with varying immunologic CD4+ T-cell
frequencies and varying degrees of virologic control.
Results: We enrolled 31 HIV-infected children of whom
29 were on ART. CD127 expression was highest in children with a CD4+
T-cell frequency in the normal range (≥ 25%, n = 23): a median 59% (47 to
68, 25th to 75th percentile) of CD8+ T cells expressed the marker. This
contrasted with 28% (21 to 37) and 22% (1 to 45) expression when the CD4+
T-cell frequency was 15 to 24% (n = 5) and < 15% (n = 3), respectively (p = 0.002). There was a striking
correlation between CD8+ T cell CD127 expression and CD4+
T-cell frequencies (r2 = 0.63, p
< 0.001). In children with good virologic control (HIV RNA < 10,000
copies/mL, n = 22) the median CD127 expression was 59% (44 to 69), compared
with 29% (19 to 46) when virologic control was poor
(HIV RNA ≥ 10,000 copies/mL, n = 9, p = 0.005).
Conclusions: CD8+ T cell CD127 expression is
significantly higher in children with immunologic and virologic control of
their HIV disease, and appears to be a sensitive immunologic surrogate of
disease status. To assess utility of this marker in guiding clinical patient
management, we will now determine changes in CD127 expression longitudinally,
in HIV-infected children.
Keywords: IL-7 Receptor; Children; Prognosis
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