Heinz bodies

Heinz bodies (also referred to as "Heinz-Ehrlich bodies") are inclusions within red blood cells composed of denatured hemoglobin.

They are named after Robert Heinz (1865–1924), a German physician who in 1890 described these inclusions in connection with cases of hemolytic anemia.

Heinz bodies appear as small round inclusions within the red cell body, though they are not visible when stained with Romanowsky dyes. They are visualized more clearly with supravital staining (e.g., with new methylene blue, crystal violet or bromocresol green).

Heinz bodies are formed by damage to the hemoglobin component molecules, usually through oxidant damage by administered drugs, or from an inherited mutation (i.e. change of an internal amino acid residue). As a result, an electron from the hemoglobin is transferred to an oxygen molecule, which creates a reactive oxygen species (ROS) that can cause severe cell damage leading to premature cell lysis. Damaged cells are cleared by macrophages in the spleen, where the precipitate and damaged membrane are removed, leading to characteristic "bite cells". The denaturing process is irreversible and the continual elimination of damaged cells leads to Heinz body anemia.

There are several pathways leading to the hemoglobin damage.

The presence of Heinz bodies may also be a feature of hyposplenism or asplenia, when a damaged or absent spleen cannot remove these damaged cells from circulation.

In veterinary medicine, Heinz bodies are associated with the consumption of paracetamol (acetaminophen), garlic, and onions by cats,dogs, and various primates. Thiosulfate compounds in the flesh of onions have been identified as the cause.

...
Wikipedia