Objective: To determine the expression of c-kit receptor in peripheral blood mononuclear cells (PBMCs) in patients with systemic lupus erythematosus (SLE), and analyze the relationship between the c-kit expression level of PBMCs and clinical parameters. Methods: Peripheral blood mononuclear cells in 47 patients with SLE and 21 healthy volunteers were collected. Expression of c-kit mRNA in PBMCs were determined with reverse transcription-polymerase chain reaction (RT-PCR). The protein of c-kit receptor (CD117) in PBMCs was measured by flow cytometry. Results: Expression of c-kit receptor protein and mRNA in patients with active or inactive SLE (n=47) were significantly higher than those in controls. The c-kit receptor of PBMCs in SLE patients were significantly higher than those in healthy controls (n=21), the c-kit receptor of PBMCs in active patients (n=27) were significantly higher than those in inactive patients (n=20) and there was no significant difference was found between patients with inactive SLE and healthy controls(P>0.05). The c-kit receptor of PBMCs in SLE have significant association with activity index. Conclusion: Production of c-kit receptor is aberrantly increased in PBMCs in patients with SLE. C-kit receptor might be more closely related to the clinical parameters in SLE patients, which might reflect the clinical status of SLE patients. Objective: To determine the expression of c-kit receptor in peripheral blood mononuclear cells (PBMCs) in patients with systemic lupus erythematosus (SLE), and analyze the relationship between the c-kit expression level of PBMCs and clinical parameters. Methods: Peripheral blood Expression of c-kit mRNA in PBMCs were determined with reverse transcription-polymerase chain reaction (RT-PCR). The protein of c-kit receptor (CD117) in PBMCs was measured by flow cytometry. Results: Expression of c-kit receptor protein and mRNA in patients with active or inactive SLE (n = 47) were significantly higher than those in controls. The c-kit receptor of PBMCs in SLE patients were significantly higher than those in healthy controls (n = 21), the c-kit receptor of PBMCs in active patients (n = 27) were significantly higher than those in inactive patients (n = 20) and there was no significant difference was found between patien ts with inactive SLE and healthy controls (P> 0.05). The c-kit receptor of PBMCs in SLE have significant association with activity index. Conclusion: Production of c-kit receptor is aberrantly increased in PBMCs in patients with SLE. C-kit receptor might be more closely related to the clinical parameters in SLE patients, which might reflect the clinical status of SLE patients.