Expression and Functional Analysis of Toll-like Receptors in Active Systemic Lupus Erythematosus Patients

SLE patients have been shown to have the higher susceptibility to infectious diseases. Since Toll-like receptors (TLRs) play an important role in controlling microorganism infection, this study has been aimed to compare the expression and function of some TLRs in SLE with those in normal individuals to test the possible contribution of TLRs to the immuno-compromised status in SLE patients. The protein expression levels of TLR-2 TLR-4 and TLR-9 were assayed by flow cytometric analysis, and it was found that, compared with normal individuals, SLE patients expressed the lower levels of TLR-2 and TLR-4, but the higher TLR-9 levels on CD14+ monocytes. The cytokine expression in sera of SLE patients and normal individuals and in the supernatant of lupus and normal PBMCs stimulated with ligands for TLR-2, TLR-4 and TLR-9 were determined by ELISA to be compared the cytokine expression in SLE with those in normal individuals. It was found that PBMCs stimulation by LPS, CpG ODN, and sBLP resulted in attenuated IL-10 and TNF-alpha protein production in SLE patients. These results suggested that the dysregulation of TLRs expression on monocytes and abnormal cytokine production from PBMCs after TLR ligation may be involved in the development of immuno-compromised status in SLE patients.