IL-6 combined with IR or Dex augmented early intracellular pro-oxidant concentrations that were correlated to stimulation of NF-κB. In myeloma cells, upon combination with hydrogen peroxide administration, relative to TNF-α, IL-6 caused an alteration of decreased glutathione concentration and augmented NF-κB-dependent manganese superoxide dismutase (MnSOD) expression. This evidence concerns the gene SOD2 and plasma cell myeloma.