A study performed in a murine model of SLE, revealed that when splenic B cells from these animals were treated with recombinant TWEAK for 3 days, a significant up-regulation of the levels of transcription of several genes involved in B cell maturation and germinal center (GC) formation such as activation-induced cytidine deaminase (AID), B lymphocyte-induced maturation protein 1 (Blimp1) or interferon regulatory factor 4 (IRF4) was observed (23). The gene discussed is IRF4; the disease is systemic lupus erythematosus.