T cells in systemic lupus erythematosus (SLE) express an abnormal phenotype characterized by increased effector functions and deficient regulatory responses. Dipyridamole, a phosphodiesterase inhibitor extensively used in combination with low dose aspirin in secondary stroke prevention, has been proposed as a specific T cell directed treatment for SLE. Dipyridamole inhibits the calcium/calcineurin/NF-AT pathway in SLE T cells in vitro and abrogates expression of cytokines and costimulatory molecules, eventually also affecting B cell responses. Dipyridamole delays the emergence of lupus related pathology in lupus prone mice, but has not yet been studied in humans with SLE. The investigators aim to investigate the efficacy of dipyridamole in the prevention of flares in SLE patients after withdrawal of background immunosuppressive medications. The investigators will additionally evaluate the safety and tolerability of dipyridamole and its impact on quality of life measures in this population. Furthermore, the effect of dipyridamole on T and B cell biomarkers will be examined.
