title: Differentiation of autoimmune thrombocytopenia from thrombocytopenia associated with immune complex disease: systemic lupus erythematosus, hepatitis-cirrhosis, and HIV-1 infection by platelet and serum immunological measurements.
abstract: A method and approach are described to differentiate classic autoimmune thrombocytopenia (ATP) from immune complex-associated thrombocytopenia in systemic lupus (SLE), hepatitis/chronic liver disease (LIV-ITP) and HIV-1 related thrombocytopenia (HIV-1-ITP). The platelet immunologic profile of IgG, C3C4 and IgM was measured with a solid-phase ELISA, employing 125I-staphylococcal protein A to detect indicator antibody binding. Polyethylene glycol was employed to precipitate immune complexes (PEG-IC). Platelet-associated IgG (PAIgG) was 2.8-, 5.6- and 5.8-fold higher in SLE, LIV-ITP and HIV-1-ITP patients respectively compared to ATP patients: platelet C3C4 was 3.2-, 4.8- and 4.5-fold higher respectively; platelet IgM was 2.2-, 3.7- and 3.8-fold higher respectively; serum PEG-IC levels were 4.2-, 4.8- and 2.1-fold higher respectively. With all parameters measured, there was no overlap between the 75th percentile for ATP patients and the 25th percentile for all three cohorts. The likelihood of having a platelet C3C4 level higher than the highest ATP level was 69% for SLE, 90% for LIV-ITP and 94% for HIV-1-ITP respectively; with PEG-IC measurements the likelihood was 83%, 100% and 100% respectively. Serum IgG, C3, C4, IgM and PEG-IC were examined for a possible relationship with platelet measurements. Except for a positive correlation between serum and platelet IgM in ATP, r = 0.5, P < 0.04, there was no positive correlation with any of the parameters measured. An inverse correlation was noted between PEG-IC level and platelet C3C4 in SLE, r = 0.7, P < 0.04. Thus platelet immunologic profile and serum PEG-IC level measurements differentiated classic ATP from immune complex-associated thrombocytopenias (SLE, LIV-ITP, HIV-1-ITP). Except for IgM measurements in ATP, platelet measurements could not be attributed to their respective serum concentration.
authors.affiliation: Department of Pediatrics, New York University Medical School, NY, USA.
authors.forename: H
authors.initials: H
authors.lastname: Samuel
authors.forename: M
authors.initials: M
authors.lastname: Nardi
authors.forename: M
authors.initials: M
authors.lastname: Karpatkin
authors.forename: D
authors.initials: D
authors.lastname: Hart
authors.forename: M
authors.initials: M
authors.lastname: Belmont
authors.forename: S
authors.initials: S
authors.lastname: Karpatkin
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000150:complications; D000293:Adolescent; D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000097:blood*; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006505:Hepatitis / Q000150:complications; D006801:Humans; D007105:Immune Complex Diseases / Q000150:complications / Q000175:diagnosis*; D007074:Immunoglobulin G / Q000097:blood*; D008103:Liver Cirrhosis / Q000150:complications; D008180:Lupus Erythematosus, Systemic / Q000150:complications; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000032:analysis; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000150:complications / Q000175:diagnosis; D013921:Thrombocytopenia / Q000150:complications / Q000175:diagnosis*
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D011092:Polyethylene Glycols