CD4 and Autoimmunity: Characterization of GAD-specific CD4 T cell clones from 4 patients who received GAD-alum (10) showed that the majority of the clones had characteristics of bifunctional Th1/Th2 cells, leading to the speculation that they might lack immune-modulating properties and hence may not be capable of modifying autoimmunity in a clinically favorable way (27).