Aims Cytogenetic and molecular aberrations are the strongest factors in determining outcome in acute myeloid leukaemia (AML). AML with complex karyotype confers a particularly poor prognosis and is associated with morphologic dysplasia. Flow cytometric immunophenotyping (FCI) has been investigated in defining dysplasia within myelodysplastic syndromes, but little is known about immunophenotypic dysplasia in AML and correlation with genetic abnormalities. This study aimed to explore differences in antigen expression by FCI in AML with complex karyotype (AML-CK) and AML with complex karyotype and TP53 mutations (AML-TP53) compared with AML with normal karyotype (AML-NK).

Methods Twenty-five cases of AML-CK, 13 of which had abnormalities of TP53, were compared with 83 cases of AML-NK using FCI.

Results Our findings demonstrated brighter expression of CD34 with decreased CD33 and aberrant expression of CD5 in blasts of AML-CK, while AML-TP53 blasts exhibited brighter expression of CD13. Granulocytes in AML-CK exhibited brighter expression of CD5, CD7, CD10 and CD14, with brighter CD3 also seen in AML-TP53.

Conclusions Our results suggest that immunophenotypic dysplasia correlates with complex karyotype and TP53 mutation, including increased expression of T-cell antigens.