The NLR agonist PGN does not affect fibrocyte differentiation. Human PBMCs were cultured in different concentrations of PGN. 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). There was no statistically significant difference between the effect of any PGN concentration and control, according to ANOVA or t-test. Arrows indicate the concentrations of PGN used by other workers (Table 1).