Age-associated expression of KIR2DL3. Cell-surface expression of CD158b/j on CD4 T cells, CD8 T cells, and NK cells in 30 persons in the 20- to 30-year-old group (□) and 30 persons in the 70- to 85-year-old group (▩) is shown as box plots with medians, 25th and 75th percentiles as boxes and 10th and 90th percentile as whiskers (A). KIR2DL3 transcription was measured by real-time PCR in purified T-cell subsets and NK cells in 20- to 30-year-old person (n = 22; □) and 70- to 85-year-old persons (n = 21; ▩) (B). Transcript numbers are expressed relative to 10⁷ β-actin transcripts.