TLR8 and TLR9 agonists do not affect fibrocyte differentiation. Human PBMCs were cultured in different concentrations of the TLR8 agonist single-stranded RNA40 (ssRNA40) and the TLR9 agonists Escherichia coli ssDNA, ODN2006 and ODN2216. ODN2006 and ODN2216 are synthetic oligonucleotides that contain CpG dinucleotides at specific sequences. The controls for these oligonucleotides are ODN2006 control and ODN2216 control, which contain GpC dinucleotides instead of CpG dinucleotides. After 5 days, the cells were air-dried, fixed and stained, and the number of fibrocytes was counted. The results are means ± SEM of fibrocytes per 2.5 × 105 PBMCs (n = 3 separate experiments). Although high concentrations of E. coli ssDNA appear to decrease the number of fibrocytes compared to no addition, the decrease is not significant by either ANOVA or t-test. High concentrations of ODN2216 and ODN2216 control appear to increase fibrocyte number compared to no addition, but the increase is not significant by either ANOVA or t-test. Arrows indicate the concentrations of TLR agonists used by other workers (Table 1).