Precise quantitation of PAIgG: A new radiometric microtechnique

Journal Article · Thu Mar 01 04:00:00 EST 1990 · American Journal of Hematology; (USA)

DOI:https://doi.org/10.1002/ajh.2830330304· OSTI ID:6938967

Schwartz, K A; Gauger, J A; Davis, J M ^[1]

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1. Michigan State Univ., East Lansing (USA)

We report the development of a radiometric assay for platelet-bound IgG that is both sensitive and quantitative. The assay utilized 96-well millititer plates incorporating a 0.2 microns filter membrane in the bottom. A 125I-labeled monoclonal antihuman IgG, as a secondary antibody, detected the platelet-bound human IgG. Since 5 x 10(6) platelets were used for each assay, tests for platelet-bound IgG can be performed on persons with severe thrombocytopenia. For the detection of circulating antiplatelet alloantibodies, as little as 10 microliters of platelet-free plasma per assay is required. Antiplatelet IgG was quantitated by using anti-PIA1 antibody that was purified with affinity and elution and DEAE chromatography. This purified antiplatelet antibody was labeled with 125I and was used to determine the binding ratio of secondary antibody to primary antibody. Under our standard conditions, this ratio was found to be stable at approximately 0.35 over the sensitivity range of the assay. The assay can detect approximately 200 molecules of human IgG per platelet (0.1 ng of secondary antibody bound per 5 x 10(6) platelets). It has a linear range from 0 to 7,000 molecules per platelet. Quantitation of anti-PIA1 binding for platelets stored for up to 6 months under refrigeration showed no change in number of PIA1 binding sites. Clinical studies showed that 18 of 19 ITP patients had an increased number of IgG molecules per platelet as did patients with malignancy and drug-induced immune thrombocytopenia. Patients who had received multiple platelet transfusions had antiplatelet antibody in their plasma. Normal amounts of PAIgG were observed in platelets and plasma of patients with nonimmune thrombocytopenia.

• OSTI ID: 6938967
• Journal Information: American Journal of Hematology; (USA), Journal Name: American Journal of Hematology; (USA) Vol. 33:3; ISSN 0361-8609; ISSN AJHED
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
ANTIBODIES
ANTIGEN-ANTIBODY REACTIONS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CHEMICAL ANALYSIS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DIAGNOSIS
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
GLOBULINS
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
MAMMALS
MAN
MATERIALS
MONOCLONAL ANTIBODIES
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
QUANTITATIVE CHEMICAL ANALYSIS
RADIOISOTOPES
RADIOMETRIC ANALYSIS
SEPARATION PROCESSES
THERAPY
TRANSFUSIONS
VASCULAR DISEASES
VERTEBRATES