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 3 Frequencies and geometric mean levels of IL-10 responses to PHA, LSA-1 and MSP-1 peptides by presence of P. falciparum parasitemia

Condition	PHA		MSP-1 (aa 20–39)		LSA-1, T3
Blood smear	No. pos./Tot. (%)^a	Geo. mean (range)^b	No. pos./Tot (%)	Geo. mean (range)	No. pos./Tot (%)	Geo. mean (range)
P. falciparum positive	25/36 (69.4)	175.5 (0–847.4)	5/32 (15.6)	23.7 (0–445.9)	2/31 (6.5)	6.9 (0–125.2)
P. falciparum negative	11/12 (91.7)	330.1 (8.4–1247.4)	2/9 (22.2)	14.7 (0–67.7)	1/8 (12.5)	16.6 (0–125.2)
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 and had a positive or negative blood smear. ^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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