The Reduction of Systemic Lupus Erythematosus Flares :Study PLUS

Hydroxychloroquine (HCQ) is a treatment which allows preventing Systemic Lupus Erythematosus (SLE) exacerbations. HCQ can be measured in whole-blood by HPLC (High Performance Liquid Chromatography). Interindividual variability in blood HCQ concentrations is important and a correlation between HCQ level and clinical efficacy of HCQ has been demonstrated in SLE in a monocentric study of 143 unselected SLE patients. The main objective of study PLUS is to determine the potential benefits of individualized HCQ dosing schedules aimed at maintaining the whole-blood HCQ concentration above 1000 ng/ml The secondary objectives are: * To define biological and clinical hallmarks present at M1 (month 1) which are predictor of SLE exacerbations in the next 6 month, * To establish the parameters of HCQ pharmacokinetic model, by a study of population, using a "Bayésienne" approach. * To study the influence of allelic variants of drug carriers and other genes in the interindividual variability of blood HCQ concentrations. * To study the influence of the compliance in the blood HCQ concentration variability * To study the relation between blood HCQ concentrations, SLE activity and quality of life * To study the relation between blood HCQ concentrations, SLE activity and lipid profile of the patients * To study the relation between ECG abnormalities and blood HCQ concentrations * To constitute a bank of serum, a DNAbank, and a RNAbank to permit subsequent studies