Platelet associated immunoglobulins in primary biliary cirrhosis: a cause of thrombocytopenia?

Thrombocytopenia in cirrhotic patients is usually attributed to splenic pooling whereas in idiopathic thrombocytopenic purpura it is related to platelet bound immunoglobulin (PA-IgG). Since primary biliary cirrhosis (PBC) is an autoimmune disorder we have undertaken a prospective study to assess the frequency and possible relationship of PA-IgG to thrombocytopenia in this condition. Sixty-two primary biliary cirrhosis patients (28 precirrhotic; 34 cirrhotic) were studied. Twenty-five patients (40%) had raised PA-IgG of whom 18 had cirrhosis. There was a significant inverse correlation between platelet count and PA-IgG (p less than 0.001) and between platelet count and spleen size (p less than 0.001). Thrombocytopenia (platelets less than 100 X 10(9)/l) was found in nine patients (15%); all nine had raised PA-IgG and eight were cirrhotic with an enlarged spleen. Two cirrhotic patients with persistent thrombocytopenia and bleeding episodes were treated with prednisolone and showed a useful therapeutic response. These results suggest that immune mediated platelet destruction and splenic pooling of platelets may both play a part in the thrombocytopenia observed in primary biliary cirrhosis.     

The role of thrombopoietin in the thrombocytopenia of patients with liver cirrhosis

OBJECTIVES: Thrombocytopenia is a common disorder among cirrhotics that has been traditionally explained by splenic platelet pooling and destruction. Thrombopoietin (TPO), the main stimuli for thrombopoiesis is produced primarily in the liver and degraded by circulating platelets, but its role in the thrombocytopenia of liver cirrhosis is not well understood. The main goal of this study is to clarify the role of TPO in the pathogenesis of thrombocytopenia in cirrhosis. METHODS: The relation among TPO, platelet count, spleen size, portal hypertension, and liver function was studied in 33 cirrhotic patients before and after either partial splenic embolization or liver transplantation. RESULTS: Cirrhotics with thrombocytopenia had lower serum TPO levels than healthy controls (median values (interquartile range: ICR) were 120.7 (42.0-191.6) vs 756.4 (527.0-965.1) pg/mL, respectively; p<0.001). Among cirrhotics with thrombocytopenia, serum TPO was related to spleen size (rho=-0.387, p=0.046), but not to platelet count as occurs physiologically. After partial splenic embolization, TPO and platelet count increased significantly and the physiological relation between TPO and platelet count was restored (rho=-0.665, p=0.026). Similar results were observed after liver transplantation. CONCLUSIONS: Our results suggest that besides impaired production in the failing liver, an increased TPO degradation by platelets sequestered in the congested spleen may contribute to thrombocytopenia in cirrhotic patients.     

Reticulated platelets as a marker of megakaryopoiesis in liver cirrhosis; relation to thrombopoietin and hepatocyte growth factor serum concentration

BACKGROUND/AIMS: Thrombocytopenia often accompanies chronic liver diseases. It can occur due to the decrease in blood platelet production by megakaryocytes, the increase in peripheral destruction, or splenic sequestration. METHODOLOGY: We estimate the reticulated platelets by use of flow cytometry in patients with liver cirrhosis with thrombocytopenia (n-24, platelets median (M)-77g/L), with normal platelet count (n-16, platelets M-193g/L) and in healthy (n-27, platelets M-242g/L). The level of reticulated platelets was determined in whole peripheral blood stained with thiazole orange and incubated with monoclonal antibodies anti-CD41. RESULTS: Patients with liver cirrhosis and thrombocytopenia revealed significantly lower reticulated platelet levels than patients without thrombocytopenia and healthy subjects (M-1.0% vs. 1.5% vs. 2.0% respectively). The correlation between reticulated platelet level and platelet count, serum level of thrombopoietin and hepatocyte growth factor in liver cirrhosis was not established. An inverse correlation was noted between reticulated platelets and thrombopoietin (r - 0.6, p<0.01) and hepatocyte growth factor (r - 0.5, p<0.01) in the control group. A positive correlation between platelet count in liver cirrhosis and serum level of thrombopoietin (r - 0.35, p<0.05) and hepatocyte growth factor (r - 0.48, p<0.01) was observed. CONCLUSIONS: Our studies showed that decreased production of platelets by megakaryocytes due to low thrombopoietin concentration could be a possible cause of thrombocytopenia in liver cirrhosis.     

Inter-relationships between platelet count,platelet IgG,serum IgG,immune complexes and severity of liver disease

Summary Thrombocytopenia is a common finding in subjects with chronic liver diseases. A variety of mechanisms may underlie this. Immunological disturbances are commonly a feature in chronic liver disease, including hyperglobulinaemia and the presence of autoantibodies and circulating immune complexes and immune mechanisms could therefore contribute to thrombocytopenia. We have investigated the relationships between blood platelet count, serum IgG and IgG immune complexes and IgG associated with platelets in 92 subjects with chronic liver disease (27 with chronic active hepatitis, 38 with primary biliary cirrhosis and 27 with alcoholic liver disease). Severity of liver impairment was a major determinant of degree of thrombocytopenia. Also, an inverse relationship was demonstrated between platelet count and platelet-associated IgG. In subjects with chronic active hepatitis the relationships between platelet count, serum IgG immune complexes and platelet-associated IgG were consistent with a role for immune mechanisms in general and immune complexes in particular as mediators of the thrombocytopenia.     

Serum thrombopoietin in chronic liver disease: relation to severity of the disease and spleen size

BACKGROUND/AIMS: Thrombopoietin is a thrombopoietic factor mainly synthesized in the liver. Its production is regulated by the mass of megakaryocytes and platelets. Impaired production of thrombopoietin may be responsible for thrombocytopenia in chronic liver disease. METHODOLOGY: We studied thrombopoietin serum concentration in 68 patients with chronic liver disease of various degrees (39 with thrombocytopenia), in 5 patients with thrombocytopenia due to hematological disease, and in 27 healthy controls. RESULTS: Thrombopoietin concentration was higher in patients with liver disease than in controls. Patients with hematological disease had much higher thrombopoietin concentration than patients with liver disease. Among patients with liver disease and thrombocytopenia, thrombopoietin concentration was higher in cirrhosis than in chronic hepatitis. A negative correlation was found between platelet counts and spleen size and between thrombopoietin concentration and spleen size. No correlation was found between thrombopoietin concentration and liver disease severity. CONCLUSIONS: Patients with liver disease and thrombocytopenia have serum thrombopoietin concentration higher than normal controls. It seems therefore that the liver, even seriously diseased, maintains the ability to produce thrombopoietin. In the liver patients the number of circulating platelets and the serum levels of thrombopoietin are inversely correlated with the size of the spleen suggesting that thrombopoietin, although normally produced, might be turned over in platelets sequestrated in the spleen.     

Management of thrombocytopenia due to liver cirrhosis:A review

Thrombocytopenia is a common complication in liver disease and can adversely affect the treatment of liver cirrhosis,limiting the ability to administer therapy and delaying planned surgical/diagnostic procedures because of an increased risk of bleeding.Multiple factors,including splenic sequestration,reduced activity of the hematopoietic growth factor thrombopoietin,bone marrow suppression by chronic hepatitis C virus infection and anti-cancer agents,and antiviral treatment with interferon-based therapy,can contribute to the development of thrombocytopenia in cirrhotic patients.Of these factors,the major mechanisms for thrombocytopenia in liver cirrhosis are(1)platelet sequestration in the spleen;and(2)decreased production of thrombopoietin in the liver.Several treatment options,including platelet transfusion,interventional partial splenic embolization,and surgical splenectomy,are now available for severe thrombocytopenia in cirrhotic patients.Although thrombopoietin agonists and targeted agents are alternative tools for noninvasively treating thrombocytopenia due to liver cirrhosis,their ability to improve thrombocytopenia in cirrhotic patients is under investigation in clinical trials.In this review,we propose a treatment approach to thrombocytopenia according to our novel concept of splenic volume,and we describe the current management of thrombocytopenia due to liver cirrhosis.     

Thrombocytopenia associated with liver cirrhosis and hepatitis C viral infection: role of thrombopoietin

BACKGROUND/AIMS: Thrombocytopenia in chronic liver diseases has traditionally been considered a consequence of platelet pooling and destruction in spleen. We tried to evaluate the influence of thrombopoietin, the physiological regulator of thrombopoiesis, on the origin of this thrombocytopenia. METHODOLOGY: We determined serum thrombopoietin levels by ELISA in thrombocytopenic patients with liver cirrhosis (n = 32) and with chronic hepatitis C viral infection (n = 23). A group of 43 healthy subjects was used as a control. RESULTS: Liver cirrhosis patients presented slightly, but not significantly, lower serum thrombopoietin levels (104 +/- 56 pg/mL) than controls (121 +/- 58 pg/mL) or patients infected with chronic hepatitis C virus (125 +/- 40 pg/mL). No correlations were found between serum thrombopoietin concentrations and liver tests or hematological parameters. CONCLUSIONS: We conclude that low thrombopoietin production may play a role, along with hypersplenism, in the development of thrombocytopenia in patients with liver cirrhosis. Normal thrombopoietin levels exclude a defect in thrombopoietin production as a possible etiology for the thrombocytopenia in patients with chronic hepatitis C viral infection. However, a direct viral megakaryocyte infection or an immune mechanism could explain this thrombocytopenia, according to the thrombopoietin levels detected.     

Role of elevated platelet-associated immunoglobulin G and hypersplenism in thrombocytopenia of chronic liver diseases

BACKGROUND AND AIM: Thrombocytopenia typically worsens with the progression of liver disease and can become a major clinical complication. Several mechanisms that contribute to thrombocytopenia have been proposed, including hypersplenism accompanied by increased platelet sequestration, platelet destruction mediated by platelet-associated immunoglobulins (PAIgG), and diminished platelet production stimulated by thrombopoietin (TPO). The purpose of the present study was to evaluate the role of each of these mechanisms in patients with liver disease-associated thrombocytopenia. METHODS: Twenty-nine patients with liver cirrhosis (LC), 20 of whom were hepatitis C virus (HCV)-seropositive, 29 chronic hepatitis (CH) patients, 24 of whom were HCV-seropositive, and 16 control patients without liver or hematopoetic disease were enrolled in this study. Serum TPO levels, PAIgG, and liver-spleen volumes were determined and correlation analyses were performed. RESULTS: No differences in serum TPO levels were observed among the three groups. The PAIgG levels were significantly elevated in CH and LC patients (mean +/- SD: 56.5 +/- 42.3 and 144.6 +/- 113.6 ng/107 cells, respectively) compared with the controls (18.9 +/- 2.5 ng/107 cells, P < 0.001 for both). Spleen volume was significantly higher only in LC (428 +/- 239) compared with CH (141 +/- 55) and control (104 +/- 50 cm3) (P < 0.001), while liver volume was not significantly different between the three groups. Correlation analyses demonstrated a significant negative correlation between platelet count with PAIgG (r = - 0.517, P < 0.001) and spleen volume (r = - 0.531, P < 0.001), and no relationship between platelet count and serum TPO level (r = 0.076). CONCLUSIONS: Serum TPO level may not be directly associated with thrombocytopenia in patients with chronic hepatitis and liver cirrhosis. In contrast, spleen volume and PAIgG are associated with thrombocytopenia in such patients, suggesting that hypersplenism and immune-mediated processes are predominant thrombocytopenic mechanisms.     

Thrombopoietin serum levels are elevated in patients with hepatitis B/C infection compared to other causes of chronic liver disease

BACKGROUND/AIMS: Thrombocytopenia in patients with advanced liver disease may stem from a deficient hepatic thrombopoietin production. METHODS: We determined the relationship between thrombopoietin, thrombocytopenia, aetiology and extent of liver damage by incorporating serum thrombopoietin measurements in the pretransplant evaluation of 111 patients with liver disease. RESULTS: The extent of thrombocytopenia was related to the underlying cause of disease. The platelet count directly correlated with factor V, II, fibrinogen, and PTT, and a negative correlation was found for splenic size and Child's stage. The thrombopoietin concentrations were age-dependent, and no significant difference resulted between the median thrombopoietin level of liver disease patients with age-matched healthy controls. Thrombopoietin concentrations and platelet counts were not correlated. Although noncirrhotic patients had higher platelet counts than those with Child's A-C cirrhosis (p < 0.001, U-test), no such difference was found in thrombopoietin levels. Patients with hepatitis B and/or C had lower platelet counts compared to patients with nonviral diseases (p < 0.001), and their median thrombopoietin concentrations were significantly higher (p < 0.001). CONCLUSION: We conclude that thrombocytopenia in patients with liver disease is unlikely to be explained only based on a deficient hepatic production of thrombopoietin. Patients with chronic viral hepatitis have significantly elevated thrombopoietin levels; the involved pathomechanisms require further study.     

Kinetics and in vivo distribution of 111-In-labelled autologous platelets in chronic hepatic disease: mechanisms of thrombocytopenia

The kinetics and distribution in vivo of autologous 111-In-labelled platelets were studied in 20 patients with chronic hepatic disease. The patients, 16 of whom were thrombocytopenic, exhibited a shortened platelet mean life time, a reduced platelet recovery and a normal platelet turnover, the latter 2 of which were positively correlated to the platelet count. Platelet in vivo recovery was negatively correlated to the spleen volume. In accordance with this, scintigraphic studies revealed that the spleen was the major organ of platelet sequestration and destruction, the role of the liver being almost negligible. Signs of platelet destruction in the bone marrow were also found. Our results indicate that splenic platelet pooling and accelerated platelet destruction, accompanied by inability of the bone marrow to compensate for the thrombocytopenia are the main causes of the thrombocytopenia accompanying chronic hepatic disease.     

病毒性肝炎血小板减少症影响因素的研究

目的探讨病毒性肝炎血小板减少症的发病机制.方法 84例病毒性肝炎患者和20名健康志愿者分为3组,A组(48例病毒性肝炎并血小板减少症患者)、B组(36例病毒性肝炎血小板正常患者)和C组(20名健康志愿者),分别采用酶联免疫吸附法、流式细胞术、腹部彩色B超检测3组血清血小板生成素(TPO)水平、血小板相关免疫球蛋白(PAIg)及其类别PAIgG、PAIgA、PAIgM水平、脾脏大小,采用骨髓穿刺术对其中74例行骨髓细胞学检查.结果血清TPO水平A组低于C组(P<0.01)和B组(P<0.05),严重肝病血清TPO水平与血小板数相关(r=0.374,P<00.01).PAIg、PAIgG水平A组明显高于B组(P<0.001)和C组(P<0.01),血小板数与PAIg水平呈负相关(r=0.446,P<0.01),血小板数与PAIgG水平亦呈负相关(r=-0.462,P<0.01).脾脏肿大发生率A组(77.1%)明显高于B组(47.2%,P<0.01),C组无脾脏肿大发生,血小板数与脾脏大小呈负相关(r=-0.5 81,P<0.01).74例骨髓象显示A组有4例呈骨髓抑制象改变,B组和C组无一例有上述改变.结论严重肝功能受损时血清TPO水平下降,与血小板数减少直接相关.PAIg介导的自身免疫机制在病毒性肝炎血小板减少症中可能起重要作用.脾脏肿大是引起病毒性肝炎血小板减少的因素.初步发现慢性肝病有骨髓抑制现象,可能成为引起病毒性肝炎血小板减少的因素之一.     

Serum thrombopoietin levels in patients with chronic hepatitis and liver cirrhosis,and its relationship with circulating thrombocyte counts

BACKGROUND/AIMS: Thrombocytopenia in chronic liver diseases may be related to deficient production of thrombopoietin. The aim of this study was to measure serum thrombopoietin levels and to examine the relationship between serum thrombopoietin concentration, circulating platelet counts and clinical stage of the disease in patients with chronic hepatitis and liver cirrhosis. METHODOLOGY: The study included 18 patients with chronic hepatitis, 48 with liver cirrhosis and 27 healthy volunteers. Serum thrombopoietin levels were measured by enzyme-linked immunosorbent assay. Additionally, serum albumin levels, prothrombin time, circulating platelet counts and spleen volume index were determined. RESULTS: Mean serum thrombopoietin level (100.96 +/- 41.67 pg/mL) in the chronic hepatitis group was similar to that of the healthy group (97.60 +/- 43.99 pg/mL), however serum thrombopoietin levels in patients with liver cirrhosis (69.60 +/- 30.23 pg/mL) were lower than patients with chronic hepatitis and controls (p < 0.05 for both). In patients with liver cirrhosis, serum thrombopoietin levels were found to be decreased as the disease progressed (80.99 +/- 24.85 pg/mL in patients at Child-Pugh stage A, 67.92 +/- 39.37 in patients at stage B and 57.62 +/- 21.09 pg/mL in patients at stage C). Cirrhotic patients had increased prothrombin time (17.12 +/- 3.52 sec) and spleen volume index (94.38 +/- 26.48 cm2), and decreased serum albumin level (3.11 +/- 0.56 g/dL) and platelet counts (102,368 +/- 30,653/mm3) when compared to both chronic hepatitis and control groups. Thrombocytopenia was found in 31 (65%) of the patients with liver cirrhosis. In patients with liver cirrhosis, while there was a positive correlation between serum thrombopoietin and albumin levels (r = 0.36, p = 0.004), no correlation was found between platelet counts and serum thrombopoietin level, and spleen volume index. CONCLUSIONS: The findings reveal that serum thrombopoietin levels are normal in patients with chronic hepatitis, but in patients with liver cirrhosis, serum thrombopoietin levels decrease, as degree of cirrhosis progresses. The impaired production of thrombopoietin may contribute to the development of thrombocytopenia in advanced stage of liver disease.     

Hepatic fibrosis plays a central role in the pathogenesis of thrombocytopenia in patients with chronic viral hepatitis

The pathogenesis of thrombocytopenia in chronic hepatitis is not well known. This study evaluated the relationship between liver injury, serum thrombopoietin, splenomegaly and thrombocytopenia in chronic viral hepatitis. Two hundred and nine patients were enrolled, 85 with splenomegaly and 124 without. Thrombocytopenia was present in 71% and 23% of patients with or without splenomegaly respectively. In subjects with low platelet count, those with splenomegaly showed significantly lower platelet numbers than those without splenomegaly. The spleen size correlated with portal hypertension. An inverse correlation between spleen size and platelet count was observed (r = -0.54; P < 0.0001). In patients without splenomegaly, thrombocytopenia was associated with the grade of fibrosis; platelet counts were the highest in patients with fibrosis 0-2, lower in those with grade 3 (P < 0.008) and lowest in those with grade 4 (P < 0.05). These findings were independent of demographic and biochemical characteristics, hepatic necroinflammatory activity, portal hypertension and splenomegaly. Patients with normal platelet counts showed higher thrombopoietin levels than those with low platelet counts (P < 0.0001). An inverse correlation between thrombopoietin levels and fibrosis grade was observed (r = - 0.50; P < 0.0001). Median thrombopoietin levels were 58 and 27 pg/ml for fibrosis grade 0-1 and grade 4 respectively (P < 0.001). These data indicate that advanced hepatic fibrosis, causing an altered production of thrombopoietin and portal hypertension, plays the central role in the pathogenesis of thrombocytopenia in chronic viral hepatitis.     

Thrombocytopenia associated with chronic liver disease

Thrombocytopenia (platelet count <150,000/microL) is a common complication in patients with chronic liver disease (CLD) that has been observed in up to 76% of patients. Moderate thrombocytopenia (platelet count, 50,000/microL-75,000/microL) occurs in approximately 13% of patients with cirrhosis. Multiple factors can contribute to the development of thrombocytopenia, including splenic platelet sequestration, bone marrow suppression by chronic hepatitis C infection, and antiviral treatment with interferon-based therapy. Reductions in the level or activity of the hematopoietic growth factor thrombopoietin (TPO) may also play a role. Thrombocytopenia can impact routine care of patients with CLD, potentially postponing or interfering with diagnostic and therapeutic procedures including liver biopsy, antiviral therapy, and medically indicated or elective surgery. Therapeutic options to safely and effectively raise platelet levels could have a significant effect on care of these patients. Several promising novel agents that stimulate TPO and increase platelet levels, such as the oral platelet growth factor eltrombopag, are currently in development for the prevention and/or treatment of thrombocytopenia. The ability to increase platelet levels could significantly reduce the need for platelet transfusions and facilitate the use of interferon-based antiviral therapy and other medically indicated treatments in patients with liver disease.     

Immature platelet fraction measurement in patients with chronic liver disease: a convenient marker for evaluating cirrhotic change

Platelet number is often used as an indicator of the severity of liver disease. Although inadequate thrombopoietin production and decreased platelet production have been proposed as major causes of cirrhotic thrombocytopenia, the underlying mechanism has not yet been fully clarified. We examined whether the measurement of the immature platelet fraction (IPF) in thrombocytopenic patients with liver dysfunction is useful as a rapid and noninvasive method for the differential diagnosis of chronic liver diseases. We examined 20 liver cirrhosis patients, 56 patients with chronic hepatitis, 9 patients with fatty liver, and 86 patients without liver disease. The percentage value of IPF (IPF%) was measured using an XE-2100 multiparameter automatic hematology analyzer. Using a receiver operating characteristic curve, we found diagnostic significance of the absolute platelet count and the absolute number of the IPF between cirrhotic patients and noncirrhotic patients, and developed a powerful multivariate discriminant analysis (MDA) function based on the platelet count and the IPF%. The diagnostic accuracy obtained by the MDA function was superior to that obtained by the absolute number of platelets and the IPF. We therefore propose our IPF% measurement for the diagnosis of liver cirrhosis.     

Platelet dynamics in chronic liver disease using the 111Indium oxine label

Platelet dynamics in chronic liver disease have been studied using 111Indium-8-hydroxyquinolone (111In-oxine) as a platelet label. In 20 patients, mainly with alcoholic cirrhosis, the platelet mean life span was reduced in 12 and the splenic platelet pool increased, often markedly so, in 15. However, the platelet count was not significantly related to mean bile span, the splenic platelet pool, or spleen size. Whereas splenic platelet pool size is related to spleen size in most of the haematological 'big-spleen' syndromes, this did not apply to those patients with chronic liver disease. Technically, 111In-oxine is a more appropriate platelet label than 51Cr in ill and thrombocytopenic patients with liver disease.     

Platelet-Associated IgG in Acute and Chronic Hepatic Diseases

In order to investigate the role of an immune mechanism in the pathogenesis of thrombocytopenia in hepatic patients, we measured platelet associated IgG (PAIgG) in 84 patients with various hepatic diseases. Increased PAIgG levels were found in 84% of patients with chronic active hepatitis (mean 21.32 ± 8.45 fg/platelet) and in 75% of those with cirrhosis with hepatitis (mean 17.3 ± 11.2 fg/platelet). In these patients there was no significant correlation between PAIgG and platelet count. Increased PAIgG amounts were also observed in some patients with inactive cirrhosis (18%). Normal PAIgG values were found in all patients with acute viral hepatitis and chronic persistent hepatitis. An immunologic mechanism may play a role in the pathogenesis of thrombocytopenia in hepatic patients. Furthermore, measurement of PAIgG may have a great usefulness in the differential diagnosis of chronic hepatic diseases.     

Prevalence of peripheral blood cytopenias (hypersplenism) in patients with nonalcoholic chronic liver disease

OBJECTIVE: Thrombocytopenia or leukopenia in patients with chronic liver disease is often attributed to functional overactivity of the spleen (hypersplenism). Despite being a fairly common phenomenon, there is a paucity of reports on the prevalence of this syndrome in stable chronic liver disease patients with or without severe fibrosis/cirrhosis. The aim of this study was to establish the prevalence of peripheral blood cytopenia in patients with nonalcoholic cirrhosis/severe fibrosis versus patients with mild or no fibrosis on liver biopsy. METHODS: This is a retrospective chart review of 235 patients who underwent a liver biopsy. One hundred ninety-one patients met strict criteria for study entry; 28 different clinical and laboratory variables were collected from their charts review, and data were then analyzed using the SPSS statistical package. RESULTS: Of the cirrhotic patients, 64% were noted to have platelet counts consistently below 150,000 (lower limit of normal in our laboratory; mean, 144.6 +/- 89.4; median, 114), whereas only 5.5% of noncirrhotic patients had thrombocytopenia (mean, 252.2 +/- 103.4; median, 238). Leukopenia (WBC, <3,500) was relatively rare in the cirrhotic/fibrotic group, having a prevalence of 5% (7.59 +/- 4.3) versus 3.3% (10.62 +/- 14.2) of noncirrhotic patients. CONCLUSIONS: Of the patients with cirrhosis, 64% had thrombocytopenia (platelet count, <150,000). The likelihood ratio of finding a platelet count of <100,000 in patients with cirrhosis, as opposed to patients without cirrhosis, is almost 12.     

Mechanisms of thrombocytopenia in patients with lymphoproliferative diseases.

Different factors are involved in the development of thrombocytopenia in patients with lymphoproliferative disorders. Significant correlation was detected between the number of megakaryocytes in bone marrow and platelet count (r = 0.485, p = 0.002, n = 37) and significant difference between the number of megakaryocyte in patients with normal platelet count (> 200,000/microliters) and patients with marked thrombocytopenia (platelet count < 100,000/microliters). All patients in the latter group (n = 15) had a relatively low number of megakaryocytes. Low but significant reverse correlation was found between the level of platelet-associated IgG (PA-IgG) and platelet count (r = -0.249, p = 0.024, n = 82) and significant difference between the mean levels of PA-IgG in the groups of patients with platelet count > 200,000/microliters and < 100,000/microliters. PA-IgG were increased in 46% of patients in the total group and in 65% of patients with platelet count < 100,000/microliters. The correlation between platelet count and PA-IgG was about 2 times higher in splenectomized (r = -0.549, p = 0.005, n = 24) than nonsplenectomized patients. All splenectomized patients with platelet count < 100,000/microliters (n = 8) had a significant increase in PA-IgG. Serum antibodies were detected in only 7% of tested patients. This group was characterized by severe thrombocytopenia (in 6 of 10 patients--platelet count < 50,000/microliters) and a high incidence of haemorrhages (in 5 of 10 patients). Thus the depression of platelet production was suggested to be the basic cause of thrombocytopenia in lymphoproliferative disorders. Involvement of immune mechanisms was revealed in a large number of patients and correlated with a deeper and more complicated thrombocytopenia.     

Thrombocytopenia in chronic liver disease

Thrombocytopenia is a common haematological disorder in patients with chronic liver disease. It is multifactorial and severity of liver disease is the most influential factor. As a result of the increased risk of bleeding, thrombocytopenia may impact upon medical procedures, such as surgery or liver biopsy. The pathophysiology of thrombocytopenia in chronic liver disease has long been associated with the hypothesis of hypersplenism, where portal hypertension causes pooling and sequestration of all corpuscular elements of the blood, predominantly thrombocytes, in the enlarged and congested spleen. Other mechanisms of importance include bone marrow suppression by toxic substances, such as alcohol or viral infection, and immunological removal of platelets from the circulation. However, insufficient platelet recovery after relief of portal hypertension by shunt procedures or minor and transient recovery after splenic artery embolization have caused many to question the importance and relative contribution of this mechanism to thrombocytopenia. The discovery of the cytokine thrombopoietin has led to the elucidation of a central mechanism. Thrombopoietin is predominantly produced by the liver and is reduced when liver cell mass is severely damaged. This leads to reduced thrombopoiesis in the bone marrow and consequently to thrombocytopenia in the peripheral blood of patients with advanced‐stage liver disease. Restoration of adequate thrombopoietin production post‐liver transplantation leads to prompt restoration of platelet production. A number of new treatments that substitute thrombopoietin activity are available or in development.