Wright J, Lim F C, Freedman J
Vox Sang. 1980 Oct;39(4):222-4. doi: 10.1111/j.1423-0410.1980.tb01861.x.
The serum of an elderly man, group A, Le(a+b-), contained an IgM antibody that agglutinated his own cells and the cells of random group A1 donors. Over a period of 5 months, the titre of these auto-anti-A1 agglutinins was 4 at 22 degrees C.