Size of azurophil lysosomes of human PMNs determined by stereological morphometry.

The most striking feature of polymorphonuclear leukocytes is the presence of the subcellular organelles known as lysosomes. The peroxidase positive azurophil (primary) lysosomes are generally described in textbooks and the journal literature as predominantly ellipsoidal and approximately 500 nm in size. However, there appears to be no discovery research in the literature establishing that value. This is the first investigation to utilize stereological techniques for microscopic morphometry to more accurately determine the size of human azurophil (primary) lysosomes. This study reports the size of ellipsoidal azurophil lysosomes to be 335 nm with a standard deviation of 97 nm.