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Monday, October 19, 2009: 4:45 PM
204 B (Pennsylvania Convention Center)
Presentation Number: 1251
Background: The recurrence rate of anti-SSA/Ro associated congenital heart block (CHB) is 17%. Reversal of 3rd degree block has never been achieved. Prophylactic IVIG was considered based on two presumed mechanisms of efficacy, a) saturation of FcRn to accelerate maternal IgG catabolism and decrease placental transport b) elevation of macrophage FcγRIIB expression to attenuate inflammatory fetal responses. Purpose: To evaluate IVIG efficacy and safety as a preventive therapy for CHB. Methods: A multicenter open-label study based on Simon’s 2-stage optimal design was initiated. Enrollment criteria included: maternal anti-SSA/Ro antibody, a previous child with CHB/rash, nd or 3rd degree CHB in three fetuses. Results: Twenty mothers were enrolled. Sixteen children had normal PR intervals throughout the study and no manifestations of neonatal lupus. One child developed a transient rash consistent with neonatal lupus and had normal PR intervals during pregnancy and normal EKG at birth. However, the pre-determined stopping rule was reached. CHB was detected in three fetuses, at 19, 20 and 25 weeks; none followed an abnormal PR interval. One of these mothers had two previous children with CHB. Antibody titers assessed before every IVIG infusion, and at 28 wks, 34 wks and delivery were compared with values obtained at baseline. No significant changes in maternal antibody titers to SSA/Ro, SSB/La, or Ro52 were detected over the course of therapy or at delivery (P>0.05 for all comparisons). There were no changes in maternal blood pressure, severe headaches, rashes, fever or any other adverse effects related to the infusions. Neonatal weight, height, and head circumference were derived from gestational age -specific growth curves to correct for prematurity when necessary. Four (21%) of the newborns, two with CHB and two healthy, were small for gestational age (<10th centile) and 3 healthy babies (16%) were born prematurely (<37 weeks of gestation). Conclusions: IVIG at doses consistent with replacement does not prevent the recurrence of CHB or reduce maternal antibody titers. Having established safety with this protocol and feasibility of patient enrollment, subsequent studies should address the efficacy of IVIG at higher doses to exploit an anti-inflammatory effect.
Keywords: autoantibodies, intravenous immunoglobulin (IVIG) and pregnancy
Disclosure: D. M. Friedman, MedImmune, 8 ; C. Llanos, SLE Foundation Inc., NY., 2 ; P. M. Izmirly, SLE Foundation Inc, NY., 2 ; M. Y. Kim, None; J. P. Buyon, Alliance for Lupus Research , 2 .