PLACENTAL THROMBOSIS AND FETAL LOSS AFTER PASSIVE TRANSFER OF MOUSE LUPUS MONOCLONAL OR HUMAN POLYCLONAL ANTICARDIOLIPIN ANTIBODIES IN PREGNANT NAIVE BALB C MICE/

In the present study we evaluated the effect of passive transfer of a mouse monoclonal (CAM) or a human polyclonal anti-cardiolipin IgG on p regnancy outcome in BALB/c mice. The mice were immunized through the t ail vein immediately after mating with 10 mu g of monoclonal or polycl onal anti-cardiolipin antibodies. Two other groups of mice were given a mouse irrelevant monoclonal antibody or normal human polyclonal IgG respectively, at the same dose. In mice immunized with monoclonal or p olyclonal anti-cardiolipin antibody we observed a significant increase in the number of fetal resorptions and a significant reduction of the mean weights of the embryos and the placentas. In mice immunized with CAM we also found a significant decrease in the number of healthy pup s, while mice infused with human aCL antibody expressed a significant reduction in the fecundity rate. The histological examination showed w idespread thrombosis and necrosis in the placentas derived from the mi ce immunized with the anti-cardiolipin antibodies. The model supports a possible direct pathogenetic effect of anti-phospholipid antibodies in recurrent fetal loss and points out that thrombotic events at place ntal level can be instrumental in the pathogenesis of the obstetric co mplications.