CD200expression In Systemic Lupus Erythematosus And Clinical Relevance

Systemic lupus erythematosus is a kind of complicate autoimmune disease, which is characterized by the immunopathologic injury caused by the deposition of the immune complex in multiple organs. Generally, SLE is a multifactorial disease, both of the congenital predisposing factors and environmental conditions can influence the immune function and cause the deficiency of the immunoregulation mechanism.Advances in high-throughput technology such as microarray during the past decade have open new avenues to efficiently discover biomarkers for SLE. In the previous work of our lab, we used RNA extracted from peripheral blood mononuclear cells of a family of7SLE patients and4health controls, and realized that there were a number of genes whose expression were significantly different between SLE patients and health controls. Some of them such as CD200, ID3and DUSP-2played some roles in the immune regulation.In our study, we first validated the mRNA expression differences of CD200, ID3and DUSP2in the PBMC of SLE patients and health controls; then detected the expression difference of proteins which were coded by the chosen genes. Further more, we analyzed the correlations between the mRNA/protein expression and the activity of the disease and the specific organs involved, looking for the potentional biomarker and target of therapy of SLE.First, we used reverse transcription polymerase chain reaction to preliminary validate the expression differences of mRNA in PBMC of7SLE patients and6normal controls. We found that in SLE patients, the ratio of CD200/relevant gene optical density was significant decreased compared to the normal controls (p<0.05), while there were no significant differences in DUSP2and ID3.Then, we further investigated the expression of CD200and its receptor CD200R in the mRNA level by real-time PCR. Forty six SLE patients including eleven with neuropsychiatic symptoms, nineteen with renal system involved and eleven with new-onset and untreated disease were enrolled in the study. Twenty seven age-and sex-matched healthy volunteersn were also included as controls. The differences between SLE patients and controls, subgroups of SLE patients were compared by the value of△Ct (the Ct of target gene-the Ct of interal relevance gene). We found that, the value of△Ct of CD200and CD200R were significant increased in SLE patients compared to normal controls, and the value in NPSLE patients were also significant higher than SLE patients without neuropsychiatric symptoms, but there were no significant differences between SLE patients with or without renal involvement. The value of ACt was significantly correlated between CD200and CD200R.Then, we investigated the CD200expression in the cell surface with flow cytometry. Twenty SLE patients and twenty three age-and sex-matched normal controls were enrolled. The CD200expression in PBMC, T cells and B cells were detected by flow cytometry, and percentage of positive cells between SLE patients and normal controls were compared. In SLE patient, the percentage of CD200+cells were significant higher than that of normal control in PBMC(p<0.05), but signicant lower in CD3+cells(p<0.05). In CD19+cells, there was no significant difference between SLE patient and normal controls.Further more, the correlation analysis was done between the relative expression of CD200and clinical indices. There were no correlations between the relative expression of CD200, percentage of positive cells and the SLEDAI score, ESR, but the value of ACt in CD200and percentage of CD3+CD200+cells were negative related with C3(p<0.05).This study showed that, there were signification changes in CD200/CD200R in SLE patients, which may be related with the onset of SLE and neuropsychiatric symptoms. The difference between the expression of CD200in mRNA and cell surface indicated that, CD200may exist in other forms, which needed further identified.The decrease of percentage of CD200+cells in T cells suggested that it may play a role in the regulation of T cells, the influerence of cell function needed to be further investigated.