CD4 and systemic sclerosis: In normal cells the percentage of IFNγ- and IL-4-producing CD4+ cells was not altered by DPI treatment, while in SSc cells NADPH oxidase inhibition led to an increase of the number of cytokine-producing cells (25.1% vs. 21.1% for IFNγ, and 26.3% vs. 15 for IL-4, P <0.05), suggesting that IFNγ- and IL-4-production was influenced by oxidative stress (Figure 7B and C).