Platelet associated IgG, platelet survival, and platelet sequestration in thrombocytopenic states.
Platelet-associated IgG (PAIgG), platelet mean life span (MLS), and platelet sequestration sites were studied in 69 patients with immune (ITP) and presumed nonimmune thrombocytopenias (NTP). A shortened MLS was associated with elevated PAIgG (N = 46), and with normal PAIgG (N = 15). Four patients had a normal MLS, but elevated PAIgG, four patients were normal for both parameters. The highest PAIgG values occurred in ITP patients with a very short MLS. Nine NTP patients had also elevated PAIgG, but a normal or slightly shortened MLS. There was a significant double log correlation between PAIgG and MLS for ITP, but not for NTP patients. Judged from the coefficient of determination, only 10% of PAIgG were directly related to a shortened MLS. 70% of patients (N = 63) had exclusively splenic and 30% hepatosplenic sequestration. PAIgG was elevated in 29/44 patients with splenic (66%) and in 16/19 patients with hepatosplenic sequestration (84%). In ITP, PAIgG-positive cases were observed in 69% of splenic v 82% of hepatosplenic sequestration, while in NTP the corresponding figures were 6/11 and 2/2. No significant correlation between PAIgG and either sequestration type was demonstrable. We conclude that in immunologically mediated thrombocytopenia only a small portion of PAIgG accounts for a decreased MLS, and that the concentration of PAIgG per se does not determine the platelet sequestration type.
D000293:Adolescent; D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000097:blood* / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology / Q000502:physiology*; D002465:Cell Movement; D002470:Cell Survival; D002648:Child; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D013921:Thrombocytopenia / Q000097:blood* / Q000276:immunology
D007074:Immunoglobulin G