A colleague in Hungary is interested to learn how others would approach the selection of donor RBC units for patients who have the following Rh phenotype and antibody combinations (see scenarios #1& #2 below), because she is aware that there is a risk of alloimmunization to c (Rh4) in R1R1 patients who present with anti-E.

Scenario #1: A patient is R1R1, has anti-E, and needs an RBC transfusion.
Scenario #2: A patient is R2R2, has anti-C, and needs an RBC transfusion.

Do colleagues select R1R1 donor RBCs for patients in scenario #1 or merely select donor RBCs that are E-negative? Do colleagues select R2R2 donor RBCs for patients in scenario #2, or merely select donor RBCs that are C-negative?

The following comments have been received.

1. A colleague in Alaska reports that when a (big) E negative patient has anti-E, they type the patient for (little) c.  If the patient is both (little) c and (big) E negative they select (big) E and (little) c negative donor RBC units for transfusion.  In the case a (big) C negative patient has anti-C, they provide (big) C negative RBCs, but they do not do any additional testing to determine if the patient is (little) e negative.

ADDENDA Dec. 13, 2004

2. The Scientific Director of a regional blood center in Southern California reports that at this year's AABB annual meeting, Dake et al from the University of Michigan (Transfusion 2004;44:115A) showed that 65% of R1R1 patients with anti-E also had anti-c if a ficin-gel technique was used. The authors supported selection of R1R1 blood for all c negative patients with anti-E.

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator