Increased TNF-α production as the putative mechanism of action of rheumatoid arthritis and Crohn disease risk variants mirrors the success of anti-TNF therapies, whereas the higher levels of GM-CSF-producing CD8+ T cells associated with Hodgkin lymphoma protection support recent GM-CSF treatment strategies (Schuster et al., 2008). This evidence concerns the gene CD8A and rheumatoid arthritis.