Figure 4.

iNKT cells increase IL‐10 production by monocytes from healthy individuals. (A) Correlation of circulating iNKT‐cell numbers with IL‐10 levels in supernatant of LPS‐stimulated monocytes (18 h) from sarcoidosis patients (n = 18) and healthy controls (n = 12); at least three separate experiments (Spearman's Rank correlation test). Values shown are for correlation using all the data (i.e. sarcoidosis and controls). When values on cells from healthy donors and patients with sarcoidosis were analyzed separately, the correlation between healthy donor‐derived iNKT levels and IL‐10 from healthy donor‐derived monocytes was stronger (r ² = 0.86; p < 0.0001), whereas there was no significant correlation between the two parameters for sarcoidosis patients. (B) Addition of iNKT cells to LPS‐stimulated monocytes from healthy individuals increased IL‐10 expression in monocytes, as determined by intracellular cytokine staining (ICS) at 18th h (monocytes from n = 36 healthy individuals). (C) IL‐10 levels in supernatant of cocultures from (B) in a subset (n = 22) of the cohort. (D, E) IL‐12 (n = 5) and TNF‐α (n = 20) expression was determined by ICS in monocytes from healthy donors that were stimulated with LPS in the presence of healthy donor‐derived iNKT cells. (F) MCP‐1 levels were determined in the supernatant of monocytes from healthy donors that were stimulated with LPS in the presence of healthy donor‐derived iNKT cells (n = 3). (B–F) Data are shown as mean + SEM and are representative of at least two experiments, apart from (F) where only one experiment was performed.