Induction Of Apoptosis In Peripheral Blood Lymphocytes Following Treatment In Vitro With Hydroxychloroquine

Objective This study investigated the possiblitity that the antirheumatic effect ofhydroxychloroquine (HCQ) may be achieved by up-regulation of apoptosis. MethodsPeripheral blood lymphocytes collected from 13 normal controls and 16 patients withsystemic lupus erythematosus(SLE) were cultured in the presence or absence of arange of concentrations of HCQ. Cells undergoing apoptosis were identified by twostandard methods, including morphologic changes, and flow cytometry. For someexperiments, lymphocytes were simultaneously stained with antibodies to T cellssurface markers and with propidium iodide for dualstain flow cytometric studies. Andthey can be detected different morpholo-gical features by acridine orange/ethidiumbromide(AO/EB) double staining for fluorescence microscopy Results HCQ was ableto induce apoptosis in peripheral blood lymphcytes in a dose- and time- dependentmanner. There was no significant difference between the controls and patients cellsdetected following treatment with HCQ. Apoptotic cells look orange-red color andnucleus smaller than normal cells; dead cells look orange-red but the size of nucleuslike normal by fluoresence microscope. Conclusion The present study demonstratedthat HCQ induces apoptosis in peripheral blood lymphocytes, which leads to thespeculation that HCQ may exert its antirheumatic effect through this mec-hanism.