I am not a great resource on this subject, but here is what i found online:
The "Big E" antigen is significant because it can cause increased health risks for certain individuals. If an individual has the "E" antigen, he or she will not produce an "anti-E" antibody. In this case, the individual's immune system will tolerate the antigen. However, if the individual does not have the "E" antigen during exposure to it via childbirth or blood transfusion, the individual's immune system may build antibodies against it. This immune system response leads to potential complications such as hemolytic anemia (red blood cell destruction) or infection.
Not sure how it pertains to blood transfusions, but it may cause a person to burn through blood a little faster due to the hemolytic anemia - this may show up as a higher LDH reading.
MDS RCMD w/grade 2-3 fibrosis. Allo-MUD Feb 26, 2014. Relapsed August 2014. Free and clear of MDS since November 2014 after treatment with Vidaza and Rituxan. Experiencing autoimmune attack on CNS thought to be GVHD, some gut, skin and ocular cGVHD. Neuropathy over 80% of body.