Associations of plasma midkine and pleiotrophin levels with major clinical parameters of SLE patients were analyzed, and the results showed that both plasma midkine and pleiotrophin levels were associated with rash (P < 0.01 and P < 0.05, respectively) and anti-SSA (both P < 0.01, respectively) in SLE patients. Here, MDK is linked to systemic lupus erythematosus.