Phagocytosis level of adult healthy macrophages and monocytes in 10% JSLE, JIA and control serum. Adult healthy control macrophages were incubated in 10% JSLE (n = 8) or control (n = 7) serum and their ability to phagocytose pHrodo stained E. coli was measured by flow cytometry (A). Macrophages incubated with JSLE serum had significantly decreased phagocytosis ability compared to macrophages incubated with control serum (p = 0.021). Adult healthy monocytes were incubated with 10% JSLE (n = 10), JIA (n = 8) or control (n = 11) serum and their ability to phagocytose pHrodo stained E. coli was measured by flow cytometry. There was no significant difference in the amount of phagocytosis between any of the groups analysed (B). JSLE monocytes were incubated with E coli and either 10% matched JSLE serum, control or JIA serum (C). Levels of E coli phagocytosis were significantly lower when incubated in matched serum but these levels increased in control or JIA serum (p = 0.002 and p = 0.028 respectively). This graph is a representative experiment of the n = 6 experiments performed (C). Control monocytes were incubated with E coli and either 10% matched control serum, JSLE or JIA serum. Incubation of healthy control monocytes with 10% JSLE serum caused a significant decrease in phagocytosis ability in comparison to incubation with control serum (D; p = 0.018). This graph is a representative experiment of the n = 5 experiments performed. Data are shown as mean ± SEM and the p values were determined by the Mann Whitney U test.