IL6 and systemic lupus erythematosus: The abrogation of Treg cell function in suppressor assays in the presence of proinflammatory cytokines such as IL-1 [21], TNFα [32], IL-6 [33], and IL-12 [34] in mice or humans, and the high levels of Treg cells in human SLE, have led us to initiate studies on the role of these cytokines.