Fig. 3.

Blockade of C5a-C5aR interaction protects pregnancies from aPL antibody-associated injury. a and b, Pregnant BALB/c mice were given aPL-IgG or NH-IgG on days 8 and 12, and some also received C5aR antagonist peptide (C5aR-AP) on day 8, 30 minutes before administration of aPL-IgG. Mice were sacrificed on day 15 of pregnancy, uteri were dissected, fetuses were weighed, and frequency of fetal resorption calculated (number of resorptions/number of fetuses + number of resorptions). Treatment with C5aR-AP prevented fetal loss and growth inhibition (*P < 0.01, aPL vs. aPL + C5aR-AP). c and d, The effects of aPL-IgG on pregnancy outcomes in C5aR^−/− and C5aR^+/+ mice were compared. Pregnant mice were treated with aPL-IgG or NH-IgG as described above. C5aR^−/− mice were protected from aPL-IgG-induced fetal resorption and growth inhibition (*P < 0.05, aPL-IgG vs. NH-IgG). From Girardi et al., Complement C5a receptors and neutrophils mediate fetal injury in the antiphospholipid syndrome. J Clin Invest 2003;112:1644–1654. Republished with permission.