History of leukocytes

In 1843, ‘white globules’ were identified in the blood simultaneously by Gabriel Andral and William Addison, and shown to be associated with disease.

Addison, recognized pus cells as being blood cells that had passed out of the circulation to the site of infection. Addison, a physician of Malvern, England reported that leukocytes moved from the circulation into the tissues and that this movement increased during inflammation.

The emigration of leukocytes from blood into tissues was observed by Augustus Waller and by Addison in the early part of the 19th century and Schultz first described phagocytosis by human leukocytes in 1865. 

Shultz z also was the first reported that white blood cell were not a uniform class of cells, but have different shapes.

Thomas Wharton Jones, a London eye surgeon and physiologist in 1847 reported for the first time the amoeboid movement of leukocytes.

Leukemia was described in the intervening years but it was 1879 before Paul Ehrlich published his method for staining blood films. Paul Ehrlich, Nobel Prize winner is credited with the first description of the human basophil in 1879.

This was the birth of the blood ‘differential’ and the recognition that leukocytes are in some way associated with infectious disease.

The discovery of eosinophil, basophils and other types of cells came a bit later on the early part of the 20th century with the widespread use of blue and red dyes – hematoxylin to stain nuclei and eosin to stain cytoplasm.
History of leukocytes

Discovery of phagocytes

The history of phagocytosis is intimately associated with the rise of immunology and growth in understanding of host resistance to infection.

Elie Metchnikoff (1845 - 1916) was a Russian biologist, was one of the vital figures in modern medicine. He first observed cells apparently eating and destroying bacteria.

He called these cells phagocytes – Greek for ‘cell that eat’. He described the two principal types of phagocyte, the macrophage and the granulocyte.

He noted that the microphages were very motile, had lobulated nuclei and that they were eventually ingested by the less mobile macrophages.

Metchnikoff was the first to state clearly that the body actively defends itself against invading microbial agents.

While Metchnikoff was not the first to observe bacteria inside white blood cells, he was the first to see link between the intracellular digestion of microbes and the body’s defense mechanisms.

His view that the phagocyte was the organism’s sole defender was, however, challenged when Emil Behring and Shibasaburo Kitasato in 1890 reported that reported substances were present also in the cell free fraction of the blood.
Discovery of phagocytes