Delayed Immunologic Alloimmuization
- Immune response to foreign antigens on RBC, or WBC, and Platelets (HLA).
- Primary Alloimmunication becomes apparent weeks to months after transfusion
- Estimated to occur in unselected immunocompetent recipients.
Alloimmunization to RBC Antigens: Serology
- After alloimmuniczation, ab may fall to undetectable lefels (esp. KIDD).
- Then, after transfusion with ag+ cells, anamnestic respons may occur within hours to days with IgG ab to transfused RBCs.
- Pt. DAT may become postive even though the ab levels are not yet detectable in the serum.
- May need to ELUTE ab off RBC's to identify
- XM may be compatible
Delayed HTR signs & symptoms
May see hemolysis with high titer levels of antibody