OBJECTIVETo detect serum prolactin (PRL) level in patients with systemic lupus erythematosus (SLE) and its correlations to SLE activity and interleukin-6 (IL-6) by peripheral blood mononuclear cells (PBMCs).

METHODSAn electrochemiluminescence assay was employed to examine the serum content of PRL in 40 SLE patients and 20 healthy subjects, and the levels of IL-6 secretion by the PBMCs were detected using enzyme-linked immunosorbent assay.

RESULTSSLE patients showed a significantly higher serum level of PRL than healthy subjects, which was especially obvious in the active stage of the disease (P=0.000. Serum PRL in SLE patients was found to positively correlate to SLE Disease Activity Index (SLEDAI) (r=0.568, P=0.000). SLE patients with hyperprolactinemia showed a significantly higher level of IL-6 secretion by the PBMCs than those with normal serum PRL level (P=0.000). IL-6 secretion by the PBMCs isolated from SLE patients with normal PRL level and from healthy controls, especially the latter, increased significantly after stimulation of the cells with recombinant human PRL in vitro (P=0.000).

CONCLUSIONSerum PRL may play a role in the pathogenesis of SLE. An elevated PRL level is closely related to SLE activity and can be used to assess SLE activity. Increased serum PRL level can up-regulate the secretion of IL-6 by the PBMCs.