Instillation of diesel exhaust particles (DEP) causes systemic inflammation. Plasma cytokines (a) Interleukin-6 (IL-6) (b) Tumour necrosis factor alpha (TNFα) & (c) C-reactive protein (CRP) were detected by ELISA. Non-instilled (open columns), saline-instilled (solid column) or DEP-instilled (0.5 mg; hatched columns) animals 6 and 24 h after instillation. Results are expressed as mean ± SEM (n = 4-6). , *P < 0.05, **P < 0.01 DEP versus saline; two-way ANOVA followed by Bonferroni post-hoc test.