Effects of Palladium Nanoparticles on the Cytokine Release from Peripheral Blood Mononuclear Cells of Palladium-Sensitized Women

Objective: To investigate the effects of palladium (Pd) nanoparticles on cytokine release from peripheral blood mononuclear cells (PBMCs) of control or Pd-sensitized nonatopicwomen. Methods: TNF-alpha, IL-5, IL-10 and IFN-gamma release and/or expression from PBMCs incubated in presence of 5 to 10 nm Pd(0) nanoparticles or Pd(IV) salt (potassium hexachloropalladate) were determined by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction analysis. Transmission electronmicroscopy was performed. Results: In lipopolysaccharide-stimulated PBMCs from controls, Pd salt inhibited IFN-gamma and IL-10 release, whereas Pd nanoparticles enhanced IFN-gamma release and inhibited TNF-alpha a secretion. In lipopolysaccharide-stimulated PBMCs from Pd-sensitized women showing high IFN-gamma release, Pd nanoparticles inhibited TNF-alpha a release and Pd salt IL-10 release. TNF-alpha and IFN-gamma release and messenger RNA expression were correlated. Transmission electronmicroscopy demonstrated uptake of nanoparticles in the endocytic compartment and activation of autophagy. Conclusions: Palladium ions and nanoparticles exert different effects in vitro on the expression and release of cytokines.