PDE4C and systemic lupus erythematosus: In conclusion, this study shows for the first time, to our knowledge, that PDE4 activity is increased in lupus conditions and that among the different PDE4 inhibitors tested, NCS 613, a highly selective PDE4C inhibitor, significantly prevents disease progression by decreasing proteinuria, lowering ex vivo TNFα secretion by PBLs and increasing animal survival rate.