Quercetin attenuates IL-1β secretion by human monocytes in vitro. Blood from healthy control subjects or XIAP-deficient patients was ficolled using lymphocyte separation media, and the resulting peripheral blood mononuclear cells were cultured in 6 well plates to allow monocyte attachment to the plates. Control and XIAP-deficient patient monocytes were stimulated as indicated, and supernatants were assayed for (A) IL-1β and (B) IL-18. Bars indicate the mean, whereas lines indicate standard deviation. Wilcoxon matched-pair test was used. Exact P values noted.