Birbeck granules

Birbeck granules, also known as Birbeck bodies, are rod shaped^[1] or "tennis-racket" cytoplasmic organelles with a central linear density and a striated appearance. First described in 1961 (where they were simply termed "characteristic granules"),^[2] they are solely found in Langerhans cells.^[1] Although part of normal Langerhans cell histology, they also provide a mechanism to differentiate Langerhans cell histiocytoses (which are a group of rare conditions collectively known as histiocytoses) from proliferative disorders caused by other cell lines.

Formation is induced by langerin.^[3]

Function

The function of Birbeck granules is debated, but one theory is that they migrate to the periphery of the Langerhans cells and release their contents into the extracellular matrix. Another theory is that the Birbeck granule functions in receptor-mediated endocytosis, similar to clathrin-coated pits.

History

Birbeck granules were discovered by Michael Stanley Clive Birbeck (1925–2005), a British scientist and electron microscopist who worked at the Chester Beatty Cancer Research Institute or Institute of Cancer Research, London from 1950 until 1981.^[4]

References

Wikimedia Commons has media related to Birbeck granules.

^ ^a ^b Mc Dermott R, Ziylan U, Spehner D, et al. (January 2002). "Birbeck granules are subdomains of the endosomal recycling compartment in human epidermal Langerhans cells, which form where langerin accumulates". Mol. Biol. Cell. 13 (1): 317–35. doi:10.1091/mbc.01-06-0300. PMC 65091. PMID 11809842.
^ Birbeck MS, Breathnach AS, Everall JD (July 1961). "An electron microscope study of basal melanocytes and high-level clear cells (Langerhans cells) in vitiligo". Journal of Investigative Dermatology. 37 (1): 51–64. doi:10.1038/jid.1961.80.
^ Kissenpfennig A, Aït-Yahia S, Clair-Moninot V, et al. (January 2005). "Disruption of the langerin/CD207 gene abolishes Birbeck granules without a marked loss of Langerhans cell function". Mol. Cell. Biol. 25 (1): 88–99. doi:10.1128/MCB.25.1.88-99.2005. PMC 538791. PMID 15601833.
^ Birbeck's granules at Who Named It?

External links

Image at ouhsc.edu
Image at humpath.com

Blood film findings

Red blood cells

Size	Anisocytosis Macrocytosis Microcytosis
Shape	Poikilocytosis Membrane abnormalities Acanthocyte Codocyte Elliptocyte Hereditary elliptocytosis Spherocyte Hereditary spherocytosis Dacrocyte Echinocyte Schistocyte Degmacyte Sickle cell/drepanocyte Sickle cell disease Stomatocyte Hereditary stomatocytosis
Colour	Anisochromia Hypochromic anemia Polychromasia
Inclusion bodies	Developmental Howell–Jolly body Basophilic stippling Pappenheimer bodies Cabot rings Hemoglobin precipitation Heinz body
Other	Haemoconia Red cell agglutination Rouleaux

White blood cells

Lymphocytes	Reactive lymphocyte Smudge cell Russell bodies
Granulocytes	Hypersegmented neutrophil Arneth count Pelger–Huët anomaly Döhle bodies Toxic granulation Toxic vacuolation Critical green inclusion Alder–Reilly anomaly Jordans' anomaly Left shift
Other	Auer rod