Megathrombocytes, Platelet Regeneration Time and Platelet-Associated IgG in Idiopathic Thrombocytopenic Purpura and in Thrombocytopenia Associated with Chronic Liver Disease

Abstract

Percentage of megathrombocytes, platelet regeneration time (PRT) and platelet-Associated IgG (Pl-A-IgG) were investigated in 12 patients with clinical features consistent with idiopathic thrombocytopenic purpura and in 11 patients with thrombocytopenia associated with chronic liver disease. Bone marrow smears were also examined and megakaryocytes classified into stages I–III according to the current principle. Of 12 patients with idiopathic thrombocytopenic purpura the percentage of megathrombocytes was increased in 9, PRT reduced in 10, and Pl-A-IgG increased in 8 patients. A statistically significant correlation was found between the percentage of megathrombocytes and the level of Pl-A-IgG. A slight correlation was also found between PRT and the percentage of megathrombocytes, while a significant correlation was found between megakaryocytes in stage I and the percentage of megathrombocytes, suggesting that growth of megakaryocytes probably contributes to platelet heterogeneity. In patients with thrombocytopenia and chronic liver disease, the percentage of megathrombocytes was in the normal range. A moderately increased level of Pl-A-IgG was found only in patients with active chronic hepatitis, PRT was reduced only in a few patients, while most of them also showed an increased level of Pl-A-IgG.

T Lymphocyte Subsets and Platelet-Associated IgG in Idiopathic Thrombocytopenic Purpura: Effect of Splenectomy

“…These data are in accordance with previous results [1,2,5,6]. The fact that a high percentage of corticoidresistant ITP patients were found to have normal PAIgG has 2 possible explanations: either ITP pa tients with normal PAIgG are less responsive to corti coids, or a percentage of patients with high PAIgG at the onset of the disease could show normalization of PAIgG in later phases without remission of thrombo cytopenia [2].…”

Platelet production and destruction in liver cirrhosis

“…Some rather old observations [36][37][38][39] exist indicating increased levels of immunoglobulin G (IgG) bound to platelets in patients with chronic liver disease that suggest the presence of autoantibodies reactive to platelets. Immunoglobulin bound to platelets is also found in idiopathic thrombocytopenic purpura (ITP) [40,1], a typical autoimmune disease characterized by increased platelet destruction mediated by autoantibodies against several platelet surface antigens, including GPIIb-IIIa (being the most common) and GPIb-IX [42,43].…”

A Role of Autoantibody–Mediated Platelet Destruction in Thrombocytopenia in Patients With Cirrhosis

“…The concept that an autoantibody-mediated process is involved in cirrhotic thrombocytopenia is not new. This idea was proposed based on an increased level of PAIgG [15][16][17] as well as a negative correlation between PAIgG and the platelet count in patients with LC. 33 However, it is now widely recognized that the specificity of PAIgG for autoantibody-mediated thrombocytopenia is quite low, 18,19,34 and PAIgG is regarded as an inappropriate test for the diagnosis of ITP in a practice guideline recently developed by the American Society of Hematology.…”

“…On the other hand, several reports have shown an increased level of immunoglobulin G (IgG) bound to platelets (platelet-associated IgG [PAIgG]) in patients with chronic liver disease, [15][16][17] suggesting the presence of autoantibodies reactive with platelets in these patients. However, such increases in PAIgG are known to be rather nonspecific and are often found in patients with nonautoimmune thrombocytopenia.…”