Expression of lipid raft in peripheral B cell from SLE patients and effect of dexamethasone on its expression

LIU Shi-lin; LIAO Yan-xia; DONG Guang-fu

doi:10.3969/j.issn.1001-9448.2018.12.015

Abstract：Objective To determine the expression of lipid rafts (LRs) of the peripheral B lymphocytes in pa-tients with SLE, and investigate the effect of dexamethasone on LRs expression.Methods Peripheral blood mononuclear cells (PBMCs) were obtained from 22 active and 11 inactive SLE patients , and 11 female healthy volunteers.B lympho-cytes were isolated by positive selection from PBMCs.Membrane staining for LRs was achieved with FITC －conjugated cholera toxin B (CTB).CD5 +B cells was evaluated by flow cytometry.The level and distribution of LRs were studied by flow cytometry and confocal microscopy.In an in vitro examination, the effect of dexamethasone (DEX) on LRs in B lym-phocytes from SLE was analyzed.Analysis of enumeration data was performed using ANOVA or paired －samples T test. Correlation was examined by Pearson correlation test.Results The number of CTB －binding lipid rafts in B cell from SLE patients was significantly higher than that in B cell from healthy controls (P＜0.01).Although there was no signifi-cant difference in expression of CD5 in B cells between SLE patients and healthy controls , a higher percentage of B cell and increased expression of LRs in CD5 +B cell were observed in SLE patients.Confocal microscopy revealed that the MFI of LRs in B cell from patients with SLE was increased and the MFI of F －actin was reduced.The LRs was found to be ir-regularly distributed and had more clusters.The number of CTB－binding LRs in B cell from SLE patients was significant-ly correlated with the SLEDAI score (R＝0.435, P＝0.008).Furthermore, in vitro results showed that DEX treatment reduced the expression of LRs in B cell from SLE patients.Conclusion Aberrant expression and distribution of lipid raft may play an important role in activation of B lymphocytes in SLE , and modulation of LRs may play a role in the treatment of SLE.