CD22 Signal Abnormalities In The Pathogenesis Of Immune Related Pancytopenia

Objective: To investigate the expression of CD22 and its downstream signal molecule spleen tyrosine kinase(SYK) and their phosphorylation of B lymphocytes in patients with immune related pancytopenia(IRP), and to explore the role of CD22 in pathogenesis of IRP. Methods: Twenty-two untreated IRP patients, twenty-four recovered IRP patients, twenty-two healthy donors and twelve Chronic lymphocytic leukemia were enrolled in this study. The expression and phosphorylation of CD22 and SYK, along with the expression of Ig G and Ig M, which obtained from B lymphocytes in peripheral blood were examined by flow cytometry. And the m RNA expression of CD22 in peripheral blood mononuclear cell(PBMNC) was measured by real-time quantitative PCR(RQ-PCR).The ratios of CD22+cells,p CD22+/CD22+cells,SYK+ cells and p SYK+/SYK+ cells of B lymphocytes, the ratio of p CD22+ cells/p SYK+ cells and their correlation, the expression of Ig G and Ig M and the expression levels of PBMNC CD22 m RNA were analyzed. Results:1. The ratios of CD22+cells and phosphorylated CD22(p CD22)+ cells of B lymphocytes in new diagnosed group[(60.03±20.94)%、(71.32±11.16)%] were significantly higher than those in remission group[(46.92±20.04)%、(55.82±14.42)%], normal control group[(46.86±17.78)%、(53.28±14.76)%] and CLL group [(39.74±18.96)%、(59.07±17.09)%](P<0.05).2. There was no statistical difference among the four groups in the ratio of SYK+cells of B lymphocytes(P>0.05).The ratio of p SYK+/SYK+ cells of B lymphocytes in new diagnosed group [2.37(0.68~15.38)% ] was significantly higher than that in remission group [1.49(0.00~3.76)%],normal control group[0.90(0.17~2.50)%] and CLL group [1.09(0.28~7.14)%](P<0.05).3. The ratio of p CD22+ cells/p SYK+cells in new diagnosed group [27.39(5.06~102.7)] was significantly lower than that in normal control group [55.95(15.25~298.53)] and CLL group [56.92(5.60~228.96)](P<0.05), and p CD22+ cells positively correlated to p SYK+ cells(r=0.341, P<0.05).4. The expression of Ig G in new diagnosed group and remission group [(19.61±9.62)%、(14.32±8.02)%] was significantly higher than that in normal control group [(7.76±3.01)%](P<0.05), and the expression of Ig M in new diagnosed group [17.16(5.21~66.35)%] was significantly higher than that in normal control group [7.37(2.77~19.00)%] and CLL group [6.96(1.35~58.96)%](P<0.05).5.The expression levels of CD22 m RNA in new diagnosed group(3.79±3.00) was significantly higher than that in remission group(1.22±0.85), normal control group(1.06±0.55) and CLL group(0.76±0.38)(P<0.05). Conclusion: The BCR signal pathway of B lymphocyte in IRP patients is enhanced, and the quantity and function of CD22 are increased, while which are still insufficient to inhibit B cell proliferation, and these may have some relationships with the pathogenesis of IRP.