The Harrington–Hollingsworth experiment was an

experiment An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into Causality, cause-and-effect by demonstrating what outcome oc ...

that established the

autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...

nature of the

blood disorder Hematologic diseases are disorders which primarily affect the blood & blood-forming organs. Hematologic diseases include rare genetic disorders, anemia, HIV, sickle cell disease & complications from chemotherapy or transfusions. Myeloid * Hemog ...

immune thrombocytopenic purpura Immune thrombocytopenic purpura (ITP), also known as idiopathic thrombocytopenic purpura or immune thrombocytopenia, is a type of thrombocytopenic purpura defined as an isolated low platelet count with a normal bone marrow in the absence of othe ...

. It was performed in 1950 by the academic staff of

Barnes-Jewish Hospital Barnes-Jewish Hospital is the largest hospital in the U.S. state of Missouri. Located in the Central West End neighborhood of St. Louis, it is the adult teaching hospital for the Washington University School of Medicine and a major component of ...

St. Louis, Missouri St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi River, Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the Greater St. Louis, ...

. __TOC__

Experiment

The experiment was undertaken in 1950 by William J. Harrington and James W. Hollingsworth, who postulated that in patients with

idiopathic thrombocytopenic purpura Immune thrombocytopenic purpura (ITP), also known as idiopathic thrombocytopenic purpura or immune thrombocytopenia, is a type of thrombocytopenic purpura defined as an isolated low platelet count with a normal bone marrow in the absence of oth ...

(ITP), it was a blood factor that caused the destruction of

platelet Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

s. To test this hypothesis, Harrington received 500 ml of blood from a patient with ITP. Within three hours, his platelets dropped to dangerously low levels and he experienced a

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...

. His platelet count remained extremely low for four days, finally returning to normal levels by the fifth day.

Bone marrow biopsy Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of condition ...

from Harrington's

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...

demonstrated normal

megakaryocyte A megakaryocyte (''mega-'' + '' karyo-'' + '' -cyte'', "large-nucleus cell") is a large bone marrow cell with a lobated nucleus responsible for the production of blood thrombocytes (platelets), which are necessary for normal blood clotting. In hum ...

s, the cells necessary for platelet production. Subsequently the experiment was repeated on all suitable staff members at the Barnes-Jewish Hospital. All subjects developed low platelet counts within three hours, and all recovered after a period of several days.

Implications

Schwartz notes that the Harrington–Hollingsworth experiment was a turning point in the understanding of ITP's pathophysiology: The experiment was the first to demonstrate that infusion of an ITP patient's plasma into a normal patient caused a precipitous drop in platelet count. This suggested that low platelet counts (

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients an ...

) in patients with ITP was caused by a circulating factor found in the blood. Many studies performed since then have demonstrated that this circulating factor is in fact a collection of

immunoglobulin An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

s. Many physician-scientists believe the findings had a major influence on the field of autoimmunity, which was not universally accepted at the time as a mechanism of human disease.

References

{{DEFAULTSORT:Harrington-Hollingsworth experiment Hematology