Tissue localization and proportion of Th17 cells in peripheral blood mononuclear cells in patients with systemic lupus erythematosus.

objective To investigate the tissue localization of CD4+T cells producing IL-17,namely Th17 cells.in patients with systemic lupus erythematosus (SLE),as well as its relationship with the activity of lupus.Methods By using H&E staining.double-label immunofluorescence.immunohistochemistry and confocal microscopy.the localization of Th17 cells was carried out in peripheral blood mononuclear cells (PBMCs).affected tissue of skin and lung obtained from 4 patients with active SLE and 2 normal human controls.Flow cytometry.reverse transcription PCR.ELISA were used to detect the proportion of Th17 cells in PBMCs,the mRNA expression of interleukin-17(IL-17)A and IL-17 F,and serum level of interleukin 17,respectively,in 50 consecutive adult patients with SLE and 15 normal human controls.Results Th17 cells were detected in PBMCs of patients with active SLE.and the fuorescence intensity of IL-17 was significantly higher in patients with active SLE than in normal human controls(127.6±20.5 vs 40.6±11.1,P＜0.001).Infiltrates of Th17 cells were noted in both skin and lung tissues of patients with active SLE.but not in those of normal human controls.The proportion of Th17 cells in PBMCs was increased in patients with active SLE.and the proportion positively correlated with SLE disease activity index(SLEDAI) (r=0.725,P＜0.01).Further more.a significant increase was observed in the mRNA expression of IL-17 A and IL-17 F and serum level of IL-17 in patients with active SLE compared with normal human controls.The amount of Th17 cells was positively correlated with the development of vasculitis.and it experienced a decrease with the remission of SLE.Conclusions A proliferation of Th17 cells is noted in patients with active SLE.which seems to closely correlated with the activity of SLE and may take part in the development of vasculitis in SLE. Key words: Lupus erythematosus,systemic; Th17 cells; Cytokines