Fig. 2.

Th1 and Th2 cytokine production are correlated differentially with age in infancy and early childhood. Whole blood cultures were stimulated for 24 h with 3 µ g/ml phorbol myristate acetate (PMA) and 3 µM ionomycin to induce cytokine protein secretion. Data are expressed as protein secretion (pg/ml) and plotted as individual points on the graph (newborns, n = 10, infants and children, n = 41; adults, n = 12). All data were included to estimate the non-parametric correlation between age and cytokine production (a–e) or cytokine/cytokine production (f, g) using the Spearman's rho test (R, rank order correlation coefficient; two-sided level of significance is indicated as P-value, P < 0·05 was regarded as significant; SPSS version 11·0).