Autoantibodies mimicking alloantibodies

A patient with myelofibrosis, who has produced many red blood cell autoantibodies, is described. Although the patient is phenotypically R1R1 (CDe/CDe), eluates made from his red blood cells have consistently contained what appeared to be anti-E, and more recently another antibody that appeared to be anti-c. In in vitro experiments we have shown that the "anti-E" and "anti-c" can be totally adsorbed by E-negative and c-negative red blood cells, respectively. We conclude that the two antibodies have quite different specificities from those indicated by simple antibody identification studies, and that both are more closely related to the anti-Hr series of antibodies than to anti-E or anti-c.