The Abnormal Expression And Significance Of Fc?R In Bechet's Disease

Objective: There are a variety of cells to express different kinds or types of Ig Fc receptors, they play an important role in promoting and regulating immune, and it include two kinds, that is the activating and inhibitory Fc?receptor. As the only inhibitory receptor, Fc?RIIB mediates negative feedback regulation of many immunocytes. Fc?RIIB can inhibit the activation of activating Fc? receptor though immunoreceptor tyrosine-based inhibition motif(ITIM) or not. A growing number of studies have shown that Fc?RIIB plays an important role in the pathogenesis of autoimmune diseases(systemic lupus erythematosus, rheumatoid arthritis), infection diseases, tumor and so on.Bechet's disease(BD) is a systemic inflammatory vasculitis of which the etiology remains unknown. The susceptible genetic factors, abnormal innate and acquired immunity play important roles in the pathogenesis of BD.There are no related researchs about Fc?R and BD at present. To find the possible pathogenesis of BD, the first part of our research observed the expression of Fc?RIIB on monocytes of BD, and the correlation with patients' disease activity. Several studies have also shown that the activating Fc?receptor contributed to phagocytosis, inflammation induced by immune complex and the release of pro-inflammatory cytokine, and its disorder would lead to many diseases. Fc?RIIB can inhibits the function of activating Fc?R, such as phagocytosis, the inflammation induced by immune complex and the release of pro-inflammatory cytokine. Therefore, we observed the expression of activating Fc?R on monocytes of BD, and the correlation with patients' disease activity in the second part. To clarify the relationship between activating Fc?R and BD will also be helpful to provide new treatment strategies for BD. The results could be used to reveal the pathogenesis of BD and provide new clues to find new targets for therapy, through the target gene therapy of Fc?Rs.Methods:We recruited untreated BD patients and sex and age matched healthy controls(HC). Flow cytometry was used for detecting the expression of Fc?RIIB on the neutrophils, monocytes, B cells, natural killer cells,dendritic cells, and T cell from the whole blood of HC and BD, as well as the expression of Fc?RI and Fc?RIII on the monocytes.The correlation between the expression of Fc?RIIB and Fc?RIII with the disease activity indexes of BD were analyzed. For further study, we detected the expression of Fc?RIIB and Fc?RIII on the monocytes after treatment of three months.Results: The expression of monocytes was significantly increased in BD patients compared with HC( percentage 60.14±3.387 vs 47.56±4.923,p=0.0365);And the expression of Fc?RIIB on monocytes was significantly decreased in BD patients compared with HC( percentage 4.78±0.61 vs7.67±1.10,p=0.0199), whereas there was no siginificant difference on the neutrophils, monocytes, natural killer cells, dendritic cells and T cells( p>0.05). The expression of Fc?RIIB on monocytes was negatively correlated with the level of ESR(r=-0.576,p=0.031)and CRP(r=-0.539,p=0.047), positively correlated with the level of Ig A in the serum(r=0.785,p=0.001), while there were no correlation between the Fc?RIIB and other clinical indexes, such as the level of Ig G, Ig M and PLT. The expression of Fc?RIII on monocytes was significantly increased in BD patients compared with HC(percentage 19.61±3.046 vs 9.349±1.107,p=0.0091), and the expression of Fc?RIII on monocytes was positively correlated with the level of ESR(r=0.2551,p=0.0274)and CRP(r=0.2354,p=0.0352),while there were no correlation between the Fc?RIII and other clinical indexes, such as the level of Ig G, Ig A,Ig M and PLT(p>0.05).There was a marked drop in the expression of Fc?RIII on monocytes after treatment(p=0.0158).Significance: Compared with HC, the expression of Fc?RIIB and Fc?RIII on monocytes were abnormal in BD patients, and their expression was correlated with the level of disease activity index. The results indicated that Fc?R might play a role in the pathogenesis of BD. This is an ealier study to look into the correlation between Fc gamma R and BD in the world.