Myeloperoxidase-deficient polymorphonuclear leucocytes (III): Relation to incidence of infection in acute myeloid leukaemia.

In 74 cases of acute myeloid leukaemia (AML) the relation between pretreatment myeloperoxidase (MPO) activity in polymorphonuclear leucocytes (PMN) and the incidence of infection in the preremission phase of the disease was investigated retrospectively. 36 patients had abnormal numbers (greater than 4%) of MPO-deficient PMN and 38 had normal numbers. In the first group more patients experienced fever attacks, more showed an infectious focus and an aetiological cause was demonstrated more frequently than among patients in the second group. This difference was statistically significant (P less than 0.01). Furthermore, the patients in the first group experienced more fever attacks, showed more infectious focus and had infectious microorganisms demonstrated in more febrile episodes than patients in the second group (P less than 0.01). The differences were not explained by differences in the incidences of neutropenia or other parameters investigated. It is concluded that decreased MPO activity in PMN from AML patients may contribute to the increased susceptibility to infections and that in the preremission phase of the disease it may account for approximately 15% of the infections.