Degmacyte

{{Short description|Abnormally shaped mature red blood cell}} 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".<ref name="yoo">{{cite journal |pages=243–8 |doi=10.1016/0002-9343(92)90071-I |title=Drug-associated 'bite cell' Hemolytic anemia |year=1992 |last1=Yoo |first1=D |journal=The American Journal of Medicine |volume=92 |issue=3 |pmid=1546722 |last2=Lessin |first2=LS}}</ref><ref name=":0">{{Cite book|last=Anderson|first=Shauna|url=https://books.google.com/books?id=fndcMwFi0KgC&dq=degmacyte&pg=PA29|title=Anderson's Atlas of Hematology|date=2013-01-24|publisher=Lippincott Williams & Wilkins|isbn=978-1-4698-2636-3|language=en}}</ref> These "bites" result from the mechanical removal of denatured hemoglobin during splenic filtration as red cells attempt to migrate through endothelial slits from splenic cords into the splenic sinuses.<ref>{{cite journal |last1=Klausner |first1=MA |last2=Hirsch |first2=LJ |last3=Leblond |first3=PF |last4=Chamberlain |first4=JK |last5=Klemperer |first5=MR |last6=Segel |first6=GB |title=Contrasting splenic mechanisms in the blood clearance of red blood cells and colloidal particles. |journal=Blood |date=December 1975 |volume=46 |issue=6 |pages=965–76 |doi=10.1182/blood.V46.6.965.965 |pmid=1203539|doi-access=free }}</ref> Bite cells are known to be a result from processes of oxidative hemolysis, such as Glucose-6-phosphate dehydrogenase deficiency, in which uncontrolled oxidative stress causes hemoglobin to denature and form Heinz bodies.<ref>{{Cite journal|last=Ford|first=J.|date=2013|title=Red blood cell morphology|journal=International Journal of Laboratory Hematology|language=en|volume=35|issue=3|pages=351–357|doi=10.1111/ijlh.12082|pmid=23480230|issn=1751-553X|doi-access=free}}</ref> Bite cells can contain more than one "bite." The "bites" in degmacytes are smaller than the missing red blood cell fragments seen in schistocytes.{{citation needed|date=February 2016}}

thumb|BITE CELLS

Degmacytes usually appear smaller, denser, and more contracted than a normal red blood cell due to the bites.<ref name=":1">{{Cite book|last=Hsi|first=Eric D.|url=https://books.google.com/books?id=IuM2DwAAQBAJ&dq=bite+cell&pg=PA42|title=Hematopathology E-Book: A Volume in the Series: Foundations in Diagnostic Pathology|date=2017-09-19|publisher=Elsevier Health Sciences|isbn=978-0-323-51231-2|language=en}}</ref> The appearance of the "bites" in red blood cells may vary in number, smoothness, and size.<ref name=":1" /> These cells can also exhibit other peripheral effects.<ref name=":0" />

==Blister cell== In blister cells or hemighost cells, an outer rim of cytoplasm 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.<ref name="TkachukHirschmann2007">{{cite book|last1=Tkachuk|first1=Douglas C.|last2=Hirschmann|first2=Jan V.|last3=Wintrobe|first3=Maxwell Myer|title=Wintrobe's Atlas of Clinical Hematology|url=https://books.google.com/books?id=Vh6c9i_umwYC&pg=PA30|year=2007|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-7023-1|page=30}}</ref>

==Causes== Bite cells are caused by G6PD deficiency, NADPH deficiency, thalassemia,<ref name=":0" /> glutathione synthase deficiency,<ref name="TkachukHirschmann2007" /> and other red-cell enzymopathies involving the pentose phosphate shunt, oxidative drugs and unstable hemoglobins.<ref name="TkachukHirschmann2007"/> People receiving large quantities of oxidative drugs such as dapsone or sulfasalazine are more prone to have degmacytes.<ref name="yoo"/> 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. <ref>{{Cite book|last=Cherry|first=Daniel A.|url=https://books.google.com/books?id=kGS1DwAAQBAJ&dq=degmacyte&pg=PA4|title=Bone Marrow: A Practical Manual|date=2011-02-25|publisher=CRC Press|isbn=978-1-4987-1296-5|language=en}}</ref><ref>{{Cite book|last=Lokwani|first=D. P.|url=https://books.google.com/books?id=1ZBfGwilkVsC&dq=degmacyte&pg=PR37|title=The ABC of CBC: Interpretation of Complete Blood Count and Histograms|date=2013-05-30|publisher=JP Medical Ltd|isbn=978-93-5025-788-3|language=en}}</ref><ref>{{Cite book|last1=Aster|first1=Jon C.|url=https://books.google.com/books?id=0fXDKpIgziQC&dq=bite+cell+blood+smear&pg=PA11|title=Hematopathology E-Book: High-Yield|last2=Pozdnyakova|first2=Olga|last3=Kutok|first3=Jeffery L.|date=2012-05-07|publisher=Elsevier Health Sciences|isbn=978-1-4557-3758-1|language=en}}</ref>

== Diagnosis == The diagnosis of degmacytes is performed by using a peripheral blood smear 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.<ref name="TkachukHirschmann2007" /> Confirming the presence of degmacytes in patients likely indicates a form of red blood cell oxidant injury or hemolysis.<ref>{{Cite book|last1=Handin|first1=Robert I.|url=https://books.google.com/books?id=H85dwxYTKLwC&dq=bite+cell+blood+smear&pg=PA1937|title=Blood: Principles and Practice of Hematology|last2=Lux|first2=Samuel E.|last3=Stossel|first3=Thomas P.|date=2003|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-1993-3|language=en}}</ref>

== Treatment and Prevention == Bite cells are primarily formed due to a G6PD deficiency 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.<ref name=":0" />

As there are currently no means of reversing red blood cell damage and the formation of degmacytes, treatment options are limited to blood transfusions.<ref name="TkachukHirschmann2007" />

==Etymology== From Ancient Greek ''δῆγμα'' (dêgma): “to bite” + -cyte.

== References == {{reflist}}

Category:Abnormal clinical and laboratory findings for RBCs