Unexpected suppression of anti-Fya and prevention of hemolytic disease of the fetus and newborn after administration of Rh immune globulin.

Background: Rh immune globulin (RhIG) has been used successfully for many years for the antenatal suppression of anti-D in D- mothers carrying D+ babies to prevent hemolytic disease of the fetus and newborn. Although the mechanism of RhIG-induced immunosuppression remains unknown, a recent report (TRANSFUSION 2006;46:1316-22) has shown that women receiving RhIG produce elevated levels of transforming growth factor (TGF)β-1, a powerful immunosuppressant cytokine. It was suggested that induction of TGFβ-1 and immunosuppression may be independent of cognate antigen recognition by RhIG.

Evidence that Hy- RBCs express weak Joa antigen.

Background: RBCs of the Hy- phenotype have, in the past, been typed as Gy(a+w), Hy-, Jo(a-), and RBCs with the Jo(a-) phenotype type Gy(a+), Hy+w, and Jo(a-). Anti-Hy and anti-Joa are difficult to identify mainly because appropriate reagent RBCs are poorly characterized. Historically, anti-Joa has not reacted with RBCs with either phenotype.