TNF and systemic lupus erythematosus: As illustrated in Table 1, the frequencies of circulating CD45RA+FoxP3low (I) T cell subsets were significantly and positively correlated with the levels of serum IL-1ß, IL-6, IL-12, TNFα and IL-2 compared to other cytokines in SLE patients, such as IFNα and IL-17.