We demonstrated that in B cells from lupus patients, CD154 stimulation induced additional activation of NF-κB signaling, including phosphorylation of P65 and IκBα, degradation of IκBα, as well as nuclear translocation of P65, but not P50 and c-Rel, and B cells from lupus patients were more sensitive to CD154 stimulation than normal B cells as the peak p65 phosphorylation was obtained with less amount of CD154 stimulation (Fig. 3). Here, CD40LG is linked to systemic lupus erythematosus.