CD28 and amyotrophic lateral sclerosis: Increased levels of IFN-γ secretion was observed in IL-2-treated CD4+ T cells of ALS patients, whereas IL-2 + anti-CD3/CD28 or IL-2 + sAJ2 treated CD4+ T cells secreted similar levels of IFN-γ secretion in ALS patients and healthy individuals (Figure 4a).