Howell-Jolly bodies are histopathological

Histopathology

Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...

 findings of basophilic nuclear

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 remnants (clusters of DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

) in circulating erythrocytes. During maturation in the bone marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

 erythrocytes normally expel their nuclei, but in some cases a small portion of DNA remains.

It is named for William Henry Howell

William Henry Howell

William Henry Howell, Ph.D., M.D., LL.D., Sc.D. was an American physiologist. He pioneered the use of heparin as a blood anti-coagulant....

 and Justin Marie Jolly

Justin Marie Jolly

Justin Marie Jolly was a French hematologist and histologist born in Melun, Seine-et-Marne. He was a pioneer in the field of hematology as it pertained to the study of living tissue....

.

Appearance

This DNA appears as a basophilic

Basophilic

Basophilic is a technical term used by histologists. It describes the microscopic appearance of cells and tissues, as seen down the microscope, after a histological section has been stained with a basic dye. The most common such dye is haematoxylin....

 (purple) spot on the otherwise eosinophilic

Eosinophilic

Eosinophilic refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

 (pink) erythrocyte on a standard H&E stain

H&E stain

H&E stain, HE stain or hematoxylin and eosin stain is a popular staining method in histology. It is the most widely used stain in medical diagnosis; for example when a pathologist looks at a biopsy of a suspected cancer, the histological section is likely to be stained with H&E and termed H&E...

ed blood smear. These inclusions are normally pitted out by the spleen

Spleen

The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

 during erythrocyte circulation, but will persist in individuals with functional hyposplenia or asplenia

Asplenia

Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced splenic functioning, but not as severely affected as with asplenism.-Congenital:...

.

Causes

Common causes of asplenia are splenectomy

Splenectomy

A splenectomy is a surgical procedure that partially or completely removes the spleen.-Indications:The spleen, similar in structure to a large lymph node, acts as a blood filter. Current knowledge of its purpose includes the removal of old red blood cells and platelets, and the detection and fight...

 following trauma

Physical trauma

Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

 to the spleen, and autosplenectomy

Autosplenectomy

An autosplenectomy occurs when a disease damages the spleen to such an extent that it ends up shrunk.-Consequences:...

 caused by sickle cell anemia. Ten percent of patients with Coeliac disease

Coeliac disease

Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward...

 also present with splenic atrophy

Atrophy

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...

 with subsequent Howell-Jolly bodies. Other causes are radiation therapy

Radiation therapy

Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...

 involving the spleen, such as that used to treat Hodgkin lymphoma. Howell-Jolly bodies are also seen in:
severe hemolytic anemia

Hemolytic anemia

Hemolytic anemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells , either in the blood vessels or elsewhere in the human body . It has numerous possible causes, ranging from relatively harmless to life-threatening...

,
megaloblastic anemia

Megaloblastic anemia

Megaloblastic anemia is an anemia that results from inhibition of DNA synthesis in red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis stage...

,
hereditary spherocytosis

Hereditary spherocytosis

Hereditary spherocytosis is a genetically-transmitted form of spherocytosis, an auto-hemolytic anemia characterized by the production of red blood cells that are sphere-shaped rather than bi-concave disk shaped , and therefore more prone to hemolysis.-Symptoms:As in non-hereditary spherocytosis,...

, and
myelodysplastic syndrome

Myelodysplastic syndrome

The myelodysplastic syndromes are a diverse collection of hematological medical conditions that involve ineffective production of the myeloid class of blood cells....

(MDS).

External links

• http://www.academic.marist.edu/~jzmz/topics/inclusions/inclusions18.html - Link currently not functional
• http://www.brown.edu/Courses/Digital_Path/systemic_path/heme/howelljolly.html