The HLA frequency of 197 leukemic patients - 66 affected by ALL, 57 by
ANLL and 74 by CML - was compared with the frequency of HLA antigens
in Caucasic population and that reported in our bone marrow donors reg
istry. The data obtained with regard to control populations show a sig
nificant association between B18 and ALL, B35 and CML; no significant
associations were found with ANLL. This suggests that one or more HLA-
linked factors or a peculiar HLA antigen could confer susceptibility t
o leukemia.