Assessment of the clinical significance of anti-Do(b)

BACKGROUND: Anti-Do(b) is an uncommon antibody, and there are few data regarding its clinical importance. In the present case, the patient's transfusion management was based on both in vivo and in vitro assay results. CASE REPORT: A delayed hemolytic transfusion reaction was suspected in a 64- year-old white woman awaiting cardiac surgery when the transfusion of 1 unit of red cells failed to raise her hematocrit. Although direct antiglobulin tests were negative, antibody screening tests on samples drawn 9 days after transfusion were positive, and anti-Do(b) was identified, reacting to a titer of 4. ⁵¹Cr in vivo survival studies with incompatible Do(b+) red cells showed poor survival: 83.2 percent at 1 hour, 43 percent at 24 hours, and 29.6 percent at 48 hours and t 1/2 = 19 hours (normal t 1/2 = 25-35 days). A monocyte monolayer assay performed with the same incompatible Do(b+) donor red cells also indicated poor survival: 22 percent and 30 percent reactive monocytes, respectively, with and without the addition of complement (normal, 0-3%). The patient was given 4 Do(b-) red cell units without clinical signs or symptoms of a reaction. CONCLUSIONS: This example of anti-Do(b) was implicated in a delayed hemolytic transfusion reaction. The ⁵¹Cr survival studies and monocyte monolayer assay results indicated that the anti-Do(b) was clinically significant, requiring the use of Do(b-) red cells for transfusion.