Rapamycin is superior to MMF. CBA-lpr^cg mice were randomizd to treatment with rapamycin, MMF, or control. Serial ultrasounds were performed every 2 weeks to document lymph node volume in cubic millimeters. Rapamycin-treated mice showed a statistically significant (P = .04) decrease in lymph node volume after 6 weeks of treatment when compared with MMF-treated mice. Bars represent mean lymph node volume from mice at each time point; error bars represent SEM. P values depict comparisons of rapamycin and MMF treatment by 2-tailed t test.