We have a patient who was last transfused 9/2011.

He was worked up a month later with a negative screen and again in Nov. 2011. In Dec. 2011 we did testing which revealed an anti-K and anti-E in the eluate and plasma.

In May of this year another hospital called saying they identified an anti-K (no E), and reported his antigen type as E+. He is typing as K-, (E+ e+). Could it be a possible auto E? From what I understand E mosaic's are rare.

Auto-antibodies with apparent Rh specificity are not uncommon. Whilst auto-anti-E is, perhaps, not as common as auto-anti-e, it is not unknown. It is revealing that the anti-E was found in the eluate, which suggests that, if the patient really is E+, the auto-antibody has a specificity that, at the very least, mimics anti-E.

It may be worthwhile reading Dwyre DM, Clapper A, Heintz M, Elbert C, Strauss RG. A red blood cell autoantibody with mimicking anti-E specificity. Transfusion 2004; 44: 1287-1292.

Malcolm beat me to it! What he said...

How many autoantibodies with mimicking specificities are limited to just that specificity. It would seem like an eluate might pick up some panagglutinin as well although it was weaker than the E-like reactivity and so would show only in the eluate. I have not seen too many mimicking autos since the days of aldomet, but the few I have seen seemed like they were just stronger with E cells but still reacted with all cells to a lesser extent. This would be mostly in gel which is very good at detecting autos.

How many autoantibodies with mimicking specificities are limited to just that specificity. It would seem like an eluate might pick up some panagglutinin as well although it was weaker than the E-like reactivity and so would show only in the eluate. I have not seen too many mimicking autos since the days of aldomet, but the few I have seen seemed like they were just stronger with E cells but still reacted with all cells to a lesser extent. This would be mostly in gel which is very good at detecting autos.

Agree entirely Mabel, but, on the toher hand, think of anti-LW. This can closely mimic anti-D, unless it is really strong, or is tested with cord D- red cells.