title: Platelet-associated IgG, IgM, and C3 in paediatric infectious disease.
abstract: Elevated amounts of platelet-associated serum proteins (PASP) can be detected in idiopathic thrombocytopenic purpura (ITP) and are considered to be of patho-aetiological importance especially in the case of acute ITP, that commonly follows acute febrile illnesses. Using a micro-enzyme-linked immunoassay we examined PASP (IgG, IgM, and C3) in 120 paediatric patients with acute fever caused by viral (n = 45), bacterial (n = 48), or non-detectable agents (n = 27) and compared those values to the levels of PASP of an own paediatric control group (n = 21). Two of the patients presented mild temporary thrombocytopenia without clinical signs in the course of their infectious disease. While having normal platelet counts, the majority of our patients (69.2%) however, showed increased levels of PASP (IgG, IgM, C3; single or combined). Significant differences of PASP levels by discrimination of viral and bacterial diseases could not be demonstrated. Elevated platelet-associated complement was of special interest, because - in the absence of low platelet counts due to platelet-specific antibodies - it must be regarded as an indicator for immune complexes (IC) binding to thrombocyte surface IgG Fc-receptors. Thus we suggest that platelets play a considerable role in the elimination of circulating IC.
authors.affiliation: University Children's Hospital, Freiburg, FRG.
authors.forename: J
authors.initials: J
authors.lastname: Forster
authors.forename: Z
authors.initials: Z
authors.lastname: Katzikadamos
authors.forename: P
authors.initials: P
authors.lastname: Zinn
mesh_terms: D000293:Adolescent; D000936:Antigen-Antibody Complex / Q000032:analysis; D001792:Blood Platelets / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003176:Complement C3 / Q000032:analysis*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D007223:Infant; D007239:Infections / Q000276:immunology*; D008297:Male; D011696:Purpura, Thrombocytopenic / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M