An En(a-) red cell sample that types as Wr(a-b-)

In the course of investigating a patient with autoimmune hemolytic anemia in which the causative autoantibody had anti-Wrb specificity, it was demonstrated that an En(a-) red blood cell sample typed as Wr(a-b-). The only known example of Wr(a+b-) blood typed as En(a+) so that anti-Wrb and anti-Ena do not have the same specificity.