CD4 and systemic lupus erythematosus: It was previously reported that plasma IL-35 and soluble gp130 levels were positively correlated with each other in SLE patients (17), and as such, we next examined the correlation of serum IL-35 levels with CD3+CD4+gp130+ or CD3+CD4─gp130+ populations (i.e. populations with SLEDAI-2K relevance) in our cohort of SLE patients.