Optical densities were converted to IU/ml and/or ng/ml based on the standard curve. (1 IU/ml = 2.4 ng/ml). Statistical analysis.  Data are presented as mean ± standard deviation (SD). Comparisons between variables were performed using general linear models with IgE levels in vitro modelled using repeated measures to control for duplicate experiments and the experimental condition as the independent variable, including age, sex and number of positive SPT as covariates. Given the small sample

size, Kruskal–Wallis Lumacaftor chemical structure tests were also performed to confirm significant differences without making any assumptions about the data distribution. The results of the two analyses were similar and general linear models are presented. A two-tailed P value of < 0.05 was considered statistically significant. All statistical analyses were performed using

sas 9.2 (SAS Institute Inc, Cary, NC, USA). When PBMC from asthmatic patients were cultured for 10 days with anti-CD40 mAb and rhIL-4, high levels of IgE were detected in supernatants on day 10 (8.2 ± 4.7 IU) (Fig. 1A). MG-132 concentration IgE responses were not detected when PBMC were cultured with either anti-CD40 mAb or rhIL-4 alone (<1.0 IU/ml) (Fig. 1A). When 1, 10 or 100 ng/ml of GTE was added to cultures, IgE production was suppressed in a dose-dependent manner (89.3 ± 5.7%, 56.9 ± 8.9%, 0.2 ± 4.1%, respectively), compared with control (general linear models, P = 0.07, <0.0001, and <0.0001, respectively) (Fig. 1B). When 5 or 50 ng/ml of EGCG was added to cultures, IgE production was also suppressed in a dose-dependent manner (87.0 ± 7.0% and 72.6 ± 14.4%, respectively), compared with none(P = 0.02 and <0.0001, respectively) (Fig. 1C). However, 0.5 ng/ml of EGCG did not significantly suppress the IgE production (95.7 ± 3.8%, P = 0.90). When PBMC from asthmatic patients were cultured for 10 days with the addition of cat pelt O-methylated flavonoid antigen (1 AU/ml), high levels of IgE were also detected in supernatants on day 10 (8.5 ± 3.8 IU) (Fig. 1A). When 1, 10 or 100 ng/ml of GTE was added to cultures, IgE production was suppressed

in a dose-dependent manner (76.4 ± 13.8%, 59.5 ± 19.5%, 0.2 ± 3.3%, respectively), compared with control (general linear models, P = 0.001, <0.0001, <0.0001, respectively) (Fig. 1B). When 50 ng/ml of EGCG was added to culture, IgE production was also suppressed in a dose-dependent manner (69.2 ± 3.7%), compared with control (P = 0.002 and <0.0001, respectively) (Fig. 1C). However, 0.5 and 5 ng/ml of EGCG did not significantly suppress IgE production (94.1 ± 4.8% and 85.0 ± 3.1%, P = 0.73 and 0.06, respectively). This study demonstrates that GTE or its catechin EGCG suppresses in vitro allergen- and non-allergen-specific IgE production in human PBMC from allergic asthmatics (up to 98%). Our findings suggest that GTE or EGCG has immunoregulatory effects on human IgE responses.