Richard J. Hirschman

The Use of Platelet Serotonin Release as a Sensitive Method for Detecting Anti‐Platelet Antibodies and a Plasma Anti‐Platelet Factor in Patients with Idiopathic Thrombocytopenic Purpura*

Summary. The method described in this paper can be used for detecting anti‐platelet iso‐, hetero‐, and drug‐antibodies and for detecting a factor in the plasma of patients with idiopathic thrombocytopenic purpura that attaches to platelets (ITP factor). Plasma from the test subject, anticoagulated with citrate, is added to a suspension of normal platelets labelled with [14C] serotonin and the amount of radioactivity (serotonin) released is measured after incubating the mixture for 45 min at 37°C. Anti‐platelet antibodies and drug antibodies that fix complement as well as isoantibodies not detectable in vitro by complement fixation or agglutination can be measured by this test. Plasma from 24 of 40 patients with ITP released significantly more serotonin than control plasmas (P < 0.025). False positive results were obtained in less than 2.5% of plasmas from normal individuals, from patients with a variety of diseases and from patients with secondary thrombocytopenia. However, plasmas from two of 13 patients with systemic lupus erythematosus and normal platelet levels gave positive results in the test. The 7S gamma globulin fractions of plasmas containing isoantibodies or ITP factor as well as acid eluates from platelets which had been incubated in these plasmas gave positive serotonin‐release tests.

Chromosomal Aberrations in Two Cases of Inherited Aplastic Anemia with Unusual Clinical Features

Abstract Two brothers had aplastic anemia similar to Fanconi anemia but without associated congenital abnormalities. Both had mild clinical courses and prolonged response to androgen therapy, one h...

Studies on the Factor VIII/von Willebrand factor antigen on human platelets.

Abstract A purified protein having both Factor VIII activity (coagulant assay) and von Willebrand factor activity (platelet retention and ristocetin aggregation assays) was used to immunize a goat. The resulting antiserum neutralized Factor VIII coagulant activity, decreased platelet retention of normal blood and blocked ristocetin aggregation of normal platelet rich plasma. This same antiserum acted as an “anti-platelet” antibody in serotonin release, platelet aggregation and immunofluorescence with normal, hemophilic and von Willebrand platelets. However, after suitable absorption with small numbers of platelets this antiserum recognized Factor VIII/von Willebrand factor antigen only on normal and hemophilic platelets but not on platelets from two patients with severe von Willebrands disease. It is possible that antisera produced against Factor VIII purified from plasma not rendered completely free of platelets contains antibodies to platelet membrane material.

Personal Burdens in Hemophilia

Excerpt Recent technical advances in the production of plasma concentrates for the treatment of hemophilia have markedly improved the outlook of the hemophiliac patient. With the appropriate provis...