Furthermore, an anti-CD154 antibody, IDEC-131 (a humanized antibody that blocks CD40-CD154 interactions [31]), was well tolerated in a phase II study conducted in 85 patients with mild-to-moderate SLE [32]; however, it failed to meet the primary efficacy end-point, namely a reduction in SLEDAI score at 20 weeks after six infusions of IDEC-131 ranging from 2.5 to 10 mg/kg. This evidence concerns the gene CD40LG and systemic lupus erythematosus.