Abstract: Objective To study the association between serum prolactin(PRL)level,prolactin receptor(PRLR)expression on peripheral blood mononuclear cells and the disease activity in the patients with systemic lupus erythematosus(SLE).Methods Serum PRL level was measured by time-resolved fluoroimmunoassay(TrFIA)in 113 patients of SLE and in 28 gender-and-age matched control subjects,SLEDAI index was estimated.It was also investigated by logistic multiple regression analysis that the association between clinical manifestations,immunologic parameters,anti-dsDNA antibody titers and hyperprolactinemia in 113 patients of SLE.The specific binding(SB)rate of peripheral blood lymphocyte PRLR was measured by radioactive binding ligand assay(RLBA)and the mRNA expression of PRLR by reverse transcription polymerase chain reaction(RT-PCR)in 24 active SLE patients,22 inactive SLE patients and 15 gender-and-age matched control subjects.Results The serum PRL levels of 63 active patients were much higher than those of 50 inactive patients and 28 control subjects.The serum PRL levels ranged 9~51.2μg/L in 79.3% of active patients.It was also found that PRL level was in positive linear correlation with the titer of anti-dsDNA antibody.The concentration of interleukin 2 receptors in hyperprolactinemia group was higher than that in normal group.It was shown that proteinuria,low levels of complement 3 and high titers of anti-dsDNA antibody were associated with hyperprolactinemia by logistic multiple regression analysis.The SB rate of PRL receptor was 5.03±2.51%(x±s),the total binding rate(TB)was 15.4±6.98% in 24 active patients with SLE.The SB rate of active patients was much higher than that of 22 inactive patients(SB4.18±2.26%,TB rate 14.03±6.54%)and that of 15 gender-and-age matched control subjects(SB1.62±1.05%,TB8.19±1.47%).The mRNA expression of PRLR in active patients(x±s,0.85±0.45)was much higher than in inactive patients(0.58±0.43)and that in control subjects(0.20±0.13).Conclusion The slightly increased serum level of PRL,high expression of PRLR and the increased specific binding rate are associated with the disease activity of SLE.

Key words: Lupus erythematosus,systemic, Prolactin, Receptor,prolactin