Interferon-gamma responses to Plasmodium falciparum liver-stage antigen-1 and merozoite-surface protein-1 increase with age in children in a malaria holoendemic area of western Kenya

Table 5 Frequencies and geometric mean levels of IL-10 responses to PHA, LSA-1 and MSP-1 peptides by age.

Condition	PHA		MSP-1 (aa 20–39)		LSA-1, T3
Age (months)	No. pos./Tot. (%)^a	Geo. mean (range)^b	No. pos./Tot (%)	Geo. mean (range)	No. pos./Tot (%)	Geo. mean (range)
0–12	7/11 (63.6)	241.4 (0–1247.0)	2/10 (20.0)	8.6 (0–48.93)	0/9 (0.0	1.3 (0–11.6)
13–24	9/12 (75.0)	155.6 (2.26–847.5)	3/10 (30.0)	19.4 (0–67.70)	1/9 (11.1)	17.5 (0–125.2)
25–36	10/13 (76.9)	195.8 (0–800.0)	0/11 (0.0)	2.7 (0–11.88)	0/11 (0.0)	1.1 (0–7.8)
37–48	10/12 (83.3)	267.7 (0.02–806.2)	2/10 (20.0)	57.9 (0–44.95)	2/10 (20.0)	16.6 (0–118.4)
P	NS^c	NS^d	NS	NS	NS	NS

^a A positive response was defined as any response ≥ 20 pg/ml above that of unstimulated cell culture supernatants. ^b Geometric mean cytokine levels in pg/ml. ^c NS= not significant. P < 0.05 considered significant, as determined by χ² test for trend across age groups. ^d P < 0.05 was considered significant as determined by analysis of variance of log-transformed values across age groups.

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