Sex Difference in Neutrophils

Abstract

The polymorphonuclear leukocyte of the human female contains a characteristic 1.5 u chromatin appendage attached to one of the main lobes of the nucleus by a fine chromatin thread. Smears of peripheral blood from 94 adults and of umbilical cord blood from 28 infants were stained by Wright''s method and, applying the above criteria, the sex of 91 adults and all 28 infants was determined correctly. The incidence of the "female appendage" amongst neutrophils from females was 1:61 in adults and 1:24 in infants. Three "female appendages" were seen in eosinophils. The occurrence of the "female appendage" in the newborn indicates a genetic basis for the observed morphologic difference and suggests an application to the determination of genetic sex in persons with hermaphroditism and related conditions. Although the smears were nearly equally divided between males and females, the "female appendage" was never seen in a neutrophil from a male.