PT - JOURNAL ARTICLE AU - C Petrarca AU - E Clemente AU - G Zaccariello AU - E Sabbioni AU - M Di Gioacchino TI - 1333 Tio<sub>2</sub> and tio<sub>2</sub>-mesoporous silica nanoparticle toxicity evaluated on primary human peripheral blood mono/lymphocytes AID - 10.1136/oemed-2018-ICOHabstracts.153 DP - 2018 Apr 01 TA - Occupational and Environmental Medicine PG - A54--A54 VI - 75 IP - Suppl 2 4099 - http://oem.bmj.com/content/75/Suppl_2/A54.1.short 4100 - http://oem.bmj.com/content/75/Suppl_2/A54.1.full SO - Occup Environ Med2018 Apr 01; 75 AB - Introduction TiO2-NPs are the most produced nanomaterial as UV filters. They are considered as nontoxic at the exposure levels of the occupational environments; nevertheless, potentially dangerous organic molecules can be formed due to photocatalysis. Mesoprous silica (SiO2) nanoparticles (MSN) incorporating Ti-nano were produced to improve their properties. We studied whether human lymphocytes/monocytes can be the target of a toxic action of all these NPs.Methods Activated/quiescent huPBMCs were exposed ex-vivo to: TiO2-NPs (21 nm); MSN (100 nm); TiO2-MSN (4.4 nm TiO2 into MSN pores). They were characterised for: cell viability/apoptosis by MTT and Annexin-V; ROS by DCFH oxidation; nuclear morphology by fluorescence microscopy; cytokines by ELISA.Results The viability of activated lymphocytes exposed to the highest doses all NPs was significantly reduced. All NPs induced apoptosis, but only TiO2-NPs induced ROS. IL-2, IL-17, IFN-g were downmodulated by all; MSNs were associated with increased IL-1β and IL-4 secretion; TiO2-NPs induced IL-10, TNF-α and IL-23.Conclusion Different patterns of cytokine in response to the three different NPs tested: they are all immunosuppressive, but only TiO2-MSN seem to act as pro-inflammatory and pro-allergic agents. The presence of TiO2 in MSN appear to influence the effects of these larger NPs, possibly related to its pro-oxidative and pro-apoptotic effect.