A 69-year-old man, suffered from lumbago, was found to have an Rh antibody with anti-f specificity that was reactive with bromelin treated f-antigen positive cells at room temperature. The antibody did not react by albumin-antihuman globulin test and was labile to DTT treatment. He had no previous history of blood transfusion. The blood groups of the patient were AB, CCDee (f-), kk, MMss, Fy (a+b+) and Jk (a-b+).
In order to evaluate the clinical significance of the antibody, an in vivo survival test of AB, ccdee (f+) donor red cells was performed. Although initial T1/2 was estimated within normal limits, an increased destruction curve was plotted after two weeks. The titre of anti-f was elevated from 1:8 to 1:32 and IgG antibody resistant against DTT treatment was developed after the in vivo survival test.
These ovservations indicated that IgM dominant anti-f may invoke hemolytic reactions.
