Massive intravenous immunoglobulin treatment in women with four or more recurrent spontaneous abortions of unexplained etiology: Down-regulation of NK cell activity and subsets

Problem: The aims of this study were to investigate the efficacy of massive intravenous immunoglobulin (MIVIg) treatment for women with recurrent spontaneous abortion (RSA) of unexplained etiology, and to investigate changes in peripheral natural killer (NK) cell activity and subsets. Method of study: MIVIg treatment was performed in 18 pregnancies from 15 women with 4 or more consecutive RSA of unexplained etiology. NK cell activity and subsets were assessed in 8 of the pregnancies. ResultS: 14 pregnancies resulted in live births and 4 resulted in abortions with chromosome abnormality. The pre-infusion NK cell activity (mean +/- SID, 40.9 +/- 17.0%) at 4.4 +/-0.5 weeks of gestation (GW) decreased to 15.0 +/-7.9% at post-infusion status (5.4 +/-0.5 GW). Pre-infusion percentages of CD56(+)CD16(-) cells (3.5 +/-2.1%) and CD56(+)CD16(-) cells (16.8 +/-8.8%) decreased to 3.0 +/-2.2% and 11.1 +/-6.9%, respectively. after MIVIg treatment. Conclusions: MIVIg treatment was effective in all 14 pregnancies from RSA women of unexplained etiology, excluding 4 abortions with chromosome abnormality. Peripheral NK cell activity and subsets were suppressed by MIVIg treatment.