BACKGROUND: Three women have been identified with an antibody to a "new" hi
gh-incidence antigen found on multiple cell lines.
CASE REPORTS: The proposita, M.A.M., presented during her third pregnancy w
ith an antibody reacting with all RBCs tested except her own. She delivered
a thrombocytopenic infant with a 3+ DAT, but without symptoms of HDN. The
second example, A.N., presented during her third pregnancy with an antibody
reacting with all RBCs tested except her own and those of M.A.M. She deliv
ered a slightly thrombocytopenic but severely anemic infant. The third exam
ple, F.K., a sister of A.N., has an antibody reacting with all RBCs tested
except her own and those of M.A.M. and A.N.
CONCLUSION: This "new" high-incidence antigen has been named MAM and assign
ed high-incidence antigen number 901016 by the International Society of Blo
od Transfusion. The corresponding antibody, anti-MAM, has been shown to cau
se HDN and has the potential to shorten RBC survival after the transfusion
of incompatible RBC units, as determined by monocyte monolayer assay. Immun
oblotting and flow cytometry show that this new antibody reacts with variou
s WBC lines in addition to RBCs. This antibody also appears to react with p
latelets in some assays.