ALDH7A1 and systemic lupus erythematosus: In contrast total cAMP-PDE activity levels in the kidneys of 18 week-old MRL/lpr lupus-prone mice are increased by 41% (P<0.001) and 24% (P<0.01) compared with 18 week-old CBA/J control and with 8 week-old MRL/lpr lupus-prone mice, respectively (Figure 2A).