Antibody to poly(ADP-ribose) as a predictor of obstetric complications in autoimmune MRL/Mp-lpr/lpr mice: basis for its application to pregnant patients with systemic lupus erythematosus.

In pregnant autoimmune MRL/Mp-lpr/lpr (MRL/l) mice with many fetuses the level of anti-poly(ADP-ribose) antibodies was found to be the same as that of age-matched non-pregnant female mice, whereas in mice with few fetuses the level of anti-poly(ADP-ribose) antibodies was high in the early period of pregnancy and rapidly returned to control level at puerperium. The anti-poly(ADP-ribose) antibody that increased during pregnancy seemed to be mono-specific for its antigen, whereas the antibody that increased with age was polyspecific. The isotype/subclass of the former was mainly IgG2a. The marked increase in anti-poly(ADP-ribose) antibodies in the early period of pregnancy suggests endogenous sensitization to poly(ADP-ribose), which may be synthesized abnormally or stored during pregnancy, and is a predictive sign in pregnant lupus mice of a low litter size. This finding is applicable to pregnant patients with systemic lupus erythematosus (SLE); that is, it is a predictive sign of fetal loss and/or maternal risk. This was confirmed in the human cases examined so far.