The Mechanism Of Interference Effect Of Proton Pump Inhibitor On Hydroxychloroquine In Patients With Systemic Lupus Erythematosus

Background Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by loss of immune tolerance, development of autoreactive T and B cells with produced autoantigens. Autoantibodies production, immune complex formation and activate complement, resulting in pathological features as vasculitis and multi-system damage. The pathogenesis is related with genetic factor, environmental factor and hormones. Hydroxychloroquine (HCQ) is widely used in the treatment of SLE, which ascribe to anti-inflammatory, lysosomal membrane stability, disease activity reduction and inhibition of IFN-a production by activated pDC in patients of SLE. But the exact mechanism is unknown. It has been reported proton pump inhibitors (PPI) induced subacute cutaneous lupus occurs in clinic, The experiments also found that PPI was antagonistic to chloroquine in vitro. This study is to explore the mechanism of interference effect of PPI on HCQ treatment in patients with SLE.Objective To investigate the possible role of proton pump inhibitors (PPI) in pDCs inhibition in patients with SLE treated with HCQ in vitro and in vivo.Methods Twenty-seven cases of inactive SLE patients met1997ACR classified criteria were enrolled in the study, including15patients treated with Prednisone(≤15mg/d) plus HCQ(400mg/d) and12patients treated with Prednisone(≤15mg/d) plus HCQ(400mg/d) and PPIs (Omeprazole20mg/d). Flow cytometry was used to measure the pDCs proportion in PBMC and the expression of CXCR4, CD32, CD40, CD86and CD62L on pDCs surface. The cord blood was collected from delivery room. The precursor pDCs were obtained using BDCA-4beads sorting and co-cultured with HCQ and PPIs in vitro (IL-3+CpG-ODN+HCQ, IL-3+CpG-ODN+HCQ+PPI). BDCA-2, CD86and CD32expression on pDCs were detected by Flow cytometry, IFN-a level in the supernatants was detected using ELISA. The pre-pDCs sorted from healthy donors using magnetic cell separation with BDCA-4beads. The pre-pDCs were co-cultured with HCQ and PPIs in vitro (IL-3, IL-3+CpG-ODN, IL-3+CpG-ODN+HCQ, IL-3+CpG-ODN+HCQ+PPI). Two days later, Fluorescent probes(pHrodoTM Red) was added. The changes of lysosome pH values was determined by laser scanning confocal microscope afte30min’s incubation.Results①Compared with the patients treated with Prednisone+HCQ, patients with Prednisone+HCQ+PPIs therapy had reduced number s of pDCs in PBMC (P<0.05) and reduced expression of CD32on pDCs (P=0.05).②The difference of expressions of CXCR4, CD40, CD86and CD62L between two groups were not significant (P>0.05).③In vitro, BDCA-2expression and MFI in HCQ+PPIs groups was significantly lower than that in HCQ groups(P<0.05).④No difference was detected in expression and MFI of CD32, CD86and IFN-a concentrations between two groups (P>0.05).⑤The fluorescence intensity of probes in lysosomals in CpG group was more enhanced than that in IL-3group. The fluorescence intensity decreased in HCQ group and further decreased in PPI group accompanied by pH elevation.Conclusion Treatment with PPI and HCQ results in decrease of pDCs number and CD32expression in patients with SLE and reduction of BDCA2expression on pDCs in vitro. PPI combine with HCQ may result in the elevation of lysosomes pH of pDCs. PPI has antagonistic effect on HCQ.