A degmacyte or bite cell is an abnormally shaped mature red blood cell with one or more semicircular portions removed from the cell margin, known as "bites". These "bites" result from the mechanical removal of denatured hemoglobin during

splenic The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

filtration as

red cells Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

attempt to migrate through endothelial slits from splenic cords into the splenic sinuses. Bite cells are known to be a result from processes of oxidative hemolysis, such as

Glucose-6-phosphate dehydrogenase deficiency Glucose-6-phosphate dehydrogenase deficiency (G6PDD), which is the most common enzyme deficiency worldwide, is an inborn error of metabolism that predisposes to red blood cell breakdown. Most of the time, those who are affected have no symptoms. ...

, in which uncontrolled oxidative stress causes hemoglobin to denature and form Heinz bodies. Bite cells can contain more than one "bite." The "bites" in degmacytes are smaller than the missing red blood cell fragments seen in

schistocyte A schistocyte or schizocyte (from Greek for "divided" and for "hollow" or "cell") is a fragmented part of a red blood cell. Schistocytes are typically irregularly shaped, jagged, and have two pointed ends. Several microangiopathic diseases, ...

Degmacytes usually appear smaller, denser, and more contracted than a normal red blood cell due to the bites. The appearance of the "bites" in red blood cells may vary in number, smoothness, and size. These cells can also exhibit other peripheral effects.

Blister cell

In blister cells, an outer rim of

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

is maintained, and when this ruptures, the resulting bite cells have horn-like projections. Blister cells appear as red blood cells containing a peripherally located

vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic m ...

Causes

Bite cells are caused by G6PD deficiency, NADPH deficiency, thalassemia, glutathione synthase deficiency, and other red-cell enzymopathies involving the

pentose phosphate shunt The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-p ...

, oxidative drugs and unstable hemoglobins. People receiving large quantities of oxidative drugs such as dapsone or sulfasalazine are more prone to have degmacytes. The underlying cause of degmacytes is a result of the splenic macrophages removing Heinz bodies from the membrane of red blood cells, which results in a "bitten" appearance of the cell.

Diagnosis

The diagnosis of degmacytes is performed by using a

peripheral blood smear A blood smear, peripheral blood smear or blood film is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood smears are examined in the ...

to analyze the red blood cells in the blood. The degmacyte look similar to a "bitten apple", which is their defining feature. However, bite cells may be difficult to distinguish from helmet cells, a fragmented red blood cell, due to the similarity in shape. Confirming the presence of degmacytes in patients likely indicates a form of red blood cell oxidant injury or

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing ( lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...

Treatment and Prevention

Bite cells are primarily formed due to a

G6PD deficiency Glucose-6-phosphate dehydrogenase deficiency (G6PDD), which is the most common enzyme deficiency worldwide, is an inborn error of metabolism that predisposes to red blood cell breakdown. Most of the time, those who are affected have no symptoms. ...

combined with oxidative stress or other trigger, such as fava beans and certain antimalarial or sulfa drugs. Patients may attempt to decrease exposure to hypoxia, which can then lead to hemolytic disorders. If one is not G6PD deficient, lessening the use of oxidative triggers may help prevent the formation of degmacytes. As there are currently no means of reversing red blood cell damage and the formation of degmacytes, treatment options are limited to

blood transfusions Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mod ...

Etymology

From

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

''δῆγμα'' (dêgma): “to bite” + -cyte.

References

Abnormal clinical and laboratory findings for RBCs {{cell-biology-stub