Table 2

Median percentages of naïve and memory T cells based on CCR7 expression in Malawian and UK adolescents (12–15 year olds) and young adults (16–25 year olds) stratified by age.


UK adolescents

(n = 30)
 Malawi adolescents
whole group
(n = 26)
 Malawi adolescents
(12-15 year olds)
(n = 5)
 Malawi young adults
(16-25 year olds)
(n = 21)




CD4+
 CD8+
 CD4+
 CD8+
 CD4+
 CD8+
 CD4+
 CD8+
%CCR7 naïve
(i.e. CD45RA+CCR7+)a
 median
 43
 55
 25
 19
 27
 16
 23
 21


range
 1–79
 15–87
 0.4–59
 1–72
 24–38
 9–41
 0.4–59
 1–72


p

0.002
 <0.001
 0.09
 0.001
 0.003
 0.001
%CCR7 memory that are central memory
(i.e. CD45RA-CCR7+)b
 median
 47
 24
 14
 4
 9
 1
 14
 5


range
 2–90
 0–73
 1–84
 0.1–54
 3–42
 0.5–6
 1–84
 0.1–54


p

0.004
 0.001
 0.007
 0.003
 0.02
 0.01
%CCR7 memory that are effector memory
(i.e. CD45RA-CCR7-)c
 median
 29
 29
 41
 31
 36
 27
 42
 32


range
 4–50
 0–56
 15–76
 12–56
 15–41
 14–34
 15–76
 12–56


p

0.02
 0.81
 0.48
 0.48
 0.01
 0.57
%CCR7 memory that are stable memory
(i.e. CD45RA+CCR7-)d
 median
 18
 42
 35
 60
 52
 73
 27
 52


range
 0.2–95
 9–100
 0.3–82
 16–87
 17–82
 61–83
 0.3–59
 16–87


p

0.16
 0.03
 0.02
 0.02
 0.50
 0.12

P values versus UK adolescents, based on Wilcoxon rank-sum test. Ranges are minimum and maximum values.

a Percentage of all CCR7 cells that are naïve.

b, c, d Of the CCR7 cells that are memory, proportion that are either central memory (b), effector memory (c) or stable memory (d) (percentages in b, c, and d sum to 100).

Ben-Smith et al. BMC Infectious Diseases 2008 8:139   doi:10.1186/1471-2334-8-139