title: Analysis of immunoglobulin class, IgG subclass and titre of HPA-1a antibodies in alloimmunized mothers giving birth to babies with or without neonatal alloimmune thrombocytopenia.
abstract: We analysed the titre and isotype composition of antibodies produced by mothers giving birth to babies with or without neonatal alloimmune thrombocytopenic purpura (NAITP) and patients with post-transfusion purpura (PTP). All these individuals produced an antibody specific for the HPA-1a allotype present on the platelet glycoprotein IIb-IIIa (GPIIb-IIIa). Sera from mothers who gave birth to thrombocytopenic babies (group 1, n = 36), non-thrombocytopenic babies (group 2, n = 4) or from PTP patients (group 3, n = 3) were tested by an indirect-ELISA. Results indicated no evident differences in the isotype composition or titre of the antibodies from the three groups of sera. The antibody titre ranged from 1:120 to 1:3500. Antibodies with the IgG1 subclass were present in all sera. Most sera contained IgG1 alone (24/43 sera tested) or in combination with IgG3 (10/43). IgG2 was never present and only three sera showed intermediate reactivity with anti-IgG4 MAb. Few sera (nine sera from groups 1 and 2) were weakly positive when tested with the anti-IgM antibodies. These results suggest that neither the titre nor the isotype composition can be used to predict the severity or the occurrence of thrombocytopenia in newborns.
authors.affiliation: Canadian Red Cross Society, Blood Services, Montreal Centre, Québec.
authors.forename: C
authors.initials: C
authors.lastname: Proulx
authors.forename: M
authors.initials: M
authors.lastname: Filion
authors.forename: M
authors.initials: M
authors.lastname: Goldman
authors.forename: A
authors.initials: A
authors.lastname: Bradley
authors.forename: D
authors.initials: D
authors.lastname: Devine
authors.forename: F
authors.initials: F
authors.lastname: Décary
authors.forename: P
authors.initials: P
authors.lastname: Chartrand
mesh_terms: D000328:Adult; D000368:Aged; D000937:Antigen-Antibody Reactions / Q000276:immunology; D016824:Antigens, Human Platelet / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007132:Immunoglobulin Isotypes / Q000097:blood*; D007147:Immunoglobulin Light Chains / Q000097:blood; D007231:Infant, Newborn; D039661:Integrin beta3; D007518:Isoantibodies / Q000097:blood*; D010976:Platelet Count; D013921:Thrombocytopenia / Q000151:congenital
chemical_list: D016824:Antigens, Human Platelet; C061248:ITGB3 protein, human; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007147:Immunoglobulin Light Chains; D039661:Integrin beta3; D007518:Isoantibodies