The First Human Example of anti‐Me

Anti‐Me is an antibody which cross‐reacts with the M and He antigens. It has previously only been found in rabbit serum; the first human example is described. The Henshaw antigen is closely associated with the MNSs system and is found in about 3% of Negroes [1–3] but only rarely in Caucasoids [2]. The original anti‐He was found in a rabbit anti‐M serum by Ikin and Mourant [1] in 1951. Other examples were deliberately produced by the immunisation of rabbits with the blood of Mr. Henshaw [3]. The first example of anti‐He in a human serum was found in 1967 by MacDonald et al. [4] in a Caucasoid mother. Although at the time it was not possible to ascertain the racial group of the father, it has since been established that he was a Negro. Other human anti‐He sera have since been found [2]. In 1961 Wiener and Rosenfield [5] reported an immune rabbit serum which possessed inseparable anti‐M and anti‐He specificities which they designated anti‐Me. The rabbit which produced the anti‐Me had almost certainly not received Henshaw‐positive cells. The rabbit serum was investigated as a result of a discrepancy found during M‐typing of a Negro involved in a medicolegal case of disputed parentage. The first human example of anti‐Me herein described was found in the serum of Mr. Richards, a 41‐year‐old Caucasoid male with no known transfusion history and has been used at this centre as an anti‐M serum for many years.