IL6 and pulmonary fibrosis: A-MWCNTs delivered to the lungs of mice by OPA had reduced mRNA or protein levels of IL-1β, IL-6, OPN and TNF-α relative to U-MWCNT at 1 or 28 days post-exposure and A-MWCNTs caused less lung fibrosis in mice relative to U-MWCNTs.