Giant neutrophils with increased peroxidase activity. Another evidence of dysgranulopoiesis in AIDS.

Using the automated hematologic analyzer Technicon H6000, which classifies leukocytes by their size and peroxidase activity, the authors have observed in nine patients with full-blown acquired immune deficiency syndrome (AIDS) a consistent increase in peroxidase content of circulating neutrophils. The increase in peroxidase activity was homogeneous in three patients (P less than 0.05). The most striking finding, however, was the occurrence of single abnormal neutrophils with peroxidase activity higher than the major neutrophil population (i.e., HPX [high peroxidase] cells). The importance of this phenomenon was correlated with the clinical status, higher HPX values being found in patients with more advanced disease. These instrumental observations were associated with the morphologic finding of atypical neutrophils, much larger than normal, with irregular nuclei and abundant cytoplasm filled with peroxidase-positive granulations. Such cells represent, in the authors' experience, the most common expression of dysgranulopoiesis in AIDS.