COEXISTENCE OF 2 DISTINCT POPULATIONS OF NEUTROPHILIC GRANULOCYTES, ONE NORMAL AND ONE PARTIAL MPO-DEFICIENT

A case of double neutrophilic population in a more or less symptomless patient is described. The diagnosis is made on one hand by the presen ce of 2 distinct neutrophil clusters on the PEROX display of the H 1 hematological automate, on the other hand by cytochemical peroxidase s taining which clearly confirms the existence of two populations. One o f the populations shows normal MPO activity, whereas the second one is characterized by partial MPO deficiency.