Myeloperoxidase‐Deficient Neutrophils in Acute Myeloid Leukaemia

Abstract

Polymorphonuclear neutrophils (PMN) lacking myeloperoxidase (MP) were found in 12 out of 28 (43 %) cases of acute myeloid leukaemia (AML) and in 2 out of 7 (28 %) cases of ‘blast‐cell transformation’ of chronic granulocytic leukaemia. This abnormality, when present, affected 8 % to 70 % of the circulating PMN. In AML this was much more common in the myeloblastic and erythroleukaemic varieties than in those with predominantly monocytic differentiation and high serum and urinary lysozyme concentrations. Auer rods were 3.3 times more common in the blast cells of AML cases with MP‐negative PMN; this correlation was highly significant (p > 0.01). Low neutrophil alkaline phosphatase was also frequently associated with absence of MP. It is suggested that these abnormalities could result from a disturbance in the function of the Golgi complex in cells derived from leukaemic stem lines. MP impairs the bactericidal capacity of PMN and may be an important factor, in addition to neutropenia, in the increased susceptibility to bacterial infections in these patients.