Harrington–Hollingsworth Experiment
Encyclopedia
The Harrington–Hollingsworth experiment was an experiment
that established the autoimmune nature of the blood disorder immune thrombocytopenic purpura. It was performed in 1950 by the academic staff of Barnes-Jewish Hospital
in St. Louis, Missouri
.
(ITP), it was a blood factor that caused the destruction of platelet
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
. His platelet count remained extremely low for four days, finally returning to normal levels by the fifth day. Bone marrow biopsy from Harrington's sternum demonstrated normal megakaryocyte
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.
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
) 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 immunoglobulins.
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
that established the autoimmune nature of the blood disorder immune thrombocytopenic purpura. It was performed in 1950 by the academic staff of Barnes-Jewish Hospital
Barnes-Jewish Hospital
Barnes-Jewish Hospital is the largest hospital in the U.S. state of Missouri. It is the adult teaching hospital for Washington University School of Medicine, and is located in St. Louis, Missouri. It is consistently rated one of the top hospitals in the United States by U.S. News & World Report...
in St. Louis, Missouri
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
.
Experiment
The experiment was undertaken in 1950 by William J. Harrington and James W. Hollingsworth, who postulated that in patients with idiopathic thrombocytopenic purpuraIdiopathic thrombocytopenic purpura
Idiopathic thrombocytopenic purpura is the condition of having an abnormally low platelet count of no known cause . As most incidents of ITP appear to be related to the production of antibodies against platelets, immune thrombocytopenic purpura or immune thrombocytopenia are terms also used to...
(ITP), it was a blood factor that caused the destruction of platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
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
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
. His platelet count remained extremely low for four days, finally returning to normal levels by the fifth day. Bone marrow biopsy from Harrington's sternum demonstrated normal megakaryocyte
Megakaryocyte
The megakaryocyte is a bone marrow cell responsible for the production of blood thrombocytes , which are necessary for normal blood clotting...
s, the cells necessary for platelet production
Thrombopoiesis
Thrombopoiesis refers to the process of thrombocyte generation.Thromobocytes are ligations of the cytoplasm from megakaryocytes. A single megakaryocyte can give rise to thousands of thrombocytes....
.
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
Thrombocytopenia is a relative decrease of platelets in blood.A normal human platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. These limits are determined by the 2.5th lower and upper percentile, so values outside this range do not necessarily indicate disease...
) 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 immunoglobulins.