Secondary immune thrombocytopenic purpura:

The many facets of immune-mediated thrombocytopenia: Principles of immunobiology and immunotherapy

Immune thrombocytopenia (ITP) is a rare autoimmune condition, due to peripheral platelet destruction through antibody-dependent cellular phagocytosis, complement-dependent cytotoxicity, cytotoxic T lymphocyte-mediated cytotoxicity, and megakaryopoiesis alteration. This condition may be idiopathic or triggered by drugs, vaccines, infections, cancers, autoimmune disorders and systemic diseases. Recent advances in our understanding of ITP immunobiology support the idea that other forms of thrombocytopenia, for instance, occurring after immunotherapy or cellular therapies, may share a common pathophysiology with possible therapeutic implications. If a decent pipeline of old and new agents is currently deployed for classical ITP, in other more complex immune-mediated thrombocytopenic disorders, clinical management is less harmonized and would deserve further prospective investigations. Here, we seek to provide a fresh overview of pathophysiology and current therapeutical algorithms for adult patients affected by this disorder with specific insights into poorly codified scenarios, including refractory ITP and post-immunotherapy/cellular therapy immune-mediated thrombocytopenia.

Impact of Helicobacter pylori Infection upon the Evolution and Outcome of Pediatric Immune Thrombocytopenic Purpura: A Comprehensive Review

In adults with immune thrombocytopenic purpura (ITP), the identification of H. pylori infection and its subsequent eradication proved to aid platelet recovery. Similar findings, at a smaller scale, were allegedly reported by some pediatric studies. This review's objective was to establish the influence of H. pylori infection and its eradication upon platelet count and recovery in pediatric ITP. Three databases, namely Pubmed, Scopus and Web of Science, were searched for pediatric studies which investigated a link between H. pylori infection and thrombocytopenia. The search results retrieved a number of 21 articles which complied to the inclusion and exclusion criteria. Some studies report lower platelet values among children with ITP and documented H. pylori infection, as well as an improve in platelet numbers after H. pylori treatment. However, results are controversial, as multiple authors failed to identify a higher prevalence of H. pylori among children with ITP or a lack of significant change in therapeutic outcome with the addition of an eradication regimen to standard treatment. The main limitations of current pediatric studies remain the small study samples and the short follow-up periods of the included subjects. Hence, the long-term impact of H. pylori in children with ITP is still uncertain.

Recommendations for the Clinical Approach to Immune Thrombocytopenia: Spanish ITP Working Group (GEPTI)

Primary immune thrombocytopenia (ITP) is a complex autoimmune disease whose hallmark is a deregulation of cellular and humoral immunity leading to increased destruction and reduced production of platelets. The heterogeneity of presentation and clinical course hampers personalized approaches for diagnosis and management. In 2021, the Spanish ITP Group (GEPTI) of the Spanish Society of Hematology and Hemotherapy (SEHH) updated a consensus document that had been launched in 2011. The updated guidelines have been the reference for the diagnosis and management of primary ITP in Spain ever since. Nevertheless, the emergence of new tools and strategies makes it advisable to review them again. For this reason, we have updated the main recommendations appropriately. Our aim is to provide a practical tool to facilitate the integral management of all aspects of primary ITP management.

Antiphospholipid antibodies and risk of post-COVID-19 vaccination thrombophilia: The straw that breaks the camel's back?

Antiphospholipid antibodies (aPLs), present in 1–5 % of healthy individuals, are associated with the risk of antiphospholipid syndrome (APS), which is the most common form of acquired thrombophilia. APLs may appear following infections or vaccinations and have been reported in patients with COronaVIrus Disease-2019 (COVID-19). However, their association with COVID-19 vaccination is unclear. Notably, a few cases of thrombocytopenia and thrombotic events resembling APS have been reported to develop in recipients of either adenoviral vector- or mRNA-based COVID-19 vaccines.

The aim of this review is therefore to speculate on the plausible role of aPLs in the pathogenesis of these rare adverse events.

Adenoviral vector-based vaccines can bind platelets and induce their destruction in the reticuloendothelial organs. Liposomal mRNA-based vaccines may instead favour activation of coagulation factors and confer a pro-thrombotic phenotype to endothelial cells and platelets. Furthermore, both formulations may trigger a type I interferon response associated with the generation of aPLs. In turn, aPLs may lead to aberrant activation of the immune response with participation of innate immune cells, cytokines and the complement cascade. NETosis, monocyte recruitment and cytokine release may further support endothelial dysfunction and promote platelet aggregation. These considerations suggest that aPLs may represent a risk factor for thrombotic events following COVID-19 vaccination, and deserve further investigations.

Updated international consensus report on the investigation and management of primary immune thrombocytopenia

Over the last decade, there have been numerous developments and changes in treatment practices for the management of patients with immune thrombocytopenia (ITP). This article is an update of the International Consensus Report published in 2010. A critical review was performed to identify all relevant articles published between 2009 and 2018. An expert panel screened, reviewed, and graded the studies and formulated the updated consensus recommendations based on the new data. The final document provides consensus recommendations on the diagnosis and management of ITP in adults, during pregnancy, and in children, as well as quality-of-life considerations.

Autoimmune Hepatitis During Ledipasvir/Sofosbuvir Treatment of Hepatitis C: A Case Report

We report the case of a woman with chronic hepatitis C and idiopathic thrombocytopenic purpura (ITP) who developed autoimmune hepatitis (AIH) during antiviral therapy with ledipasvir (LDV)/sofosbuvir (SOF). The onset of acute hepatitis rose two weeks after starting treatment with LDV/SOF when HCV‐RNA tested negative, suggesting a link between rapid HCV clearance and de novo autoimmune diseases. Conclusion: This case report proposes new immunologic scenarios in patients with hepatitis C virus (HCV) with laboratory or clinical signs of autoimmunity during direct‐acting antiviral (DAA) therapy.

Ethnic and racial difference in Helicobacter pylori infection in patients with immune thrombocytopenia treated at a major urban medical center

Immune thrombocytopenia (ITP) is an autoimmune disorder with a complex immunopathology and pathogenesis characterized by thrombocytopenia and bleeding manifestations. The disorder is separated into primary (idiopathic) ITP and secondary ITP, when associated with other immune or lymphoproliferative disorders and certain chronic infections. Helicobacter pylori (H. pylori) is a recognized bacterial cause of ITP. In regions with high prevalence of infection, bacterial eradication has resulted in improvement in platelet count. However, the prevalence of H. pylori infection and response to antimicrobial therapy in North American ITP patients is reportedly low. We evaluated the prevalence of H. pylori infection in ITP patients diagnosed and treated at a large urban medical center. Eighty-two patients were screened for H. pylori, by stool antigen (n = 54), H. pylori breath test (n = 11), and H. pylori antibodies (n = 16), of which 15 (18.3%) were white non-Hispanic (WNH), 55 (67%) Hispanic (H), 8 (9.8%) Asian (A), and 4 (4.9%) African-American (AA). Of the screened patients, 36/82 (43.9%) tested positive for H. pylori. The prevalence of H. pylori infection within the represented ethnic groups was 2/15 (13%) WNH, 29/55 (52.7%) H, 3/8 (37.5%) A, and 2/4 (50%) AA. There was a significant difference in prevalence of infection comparing WNH and H patients (p = 0.007). There were 36 treated patients, with H. pylori eradication documented in 26 patients. Fifteen of the 26 patients were evaluable for response with 8 of 15 (53%) having clinical responses, 6 complete responses, and 2 partial responses. Our study demonstrates an increased prevalence of H. pylori infection in the Hispanic ITP population with a reasonable platelet response among patients with H. pylori eradication.

Chronic Subdural Hematoma Associated with Thrombocytopenia in a Patient with Human Immunodeficiency Virus Infection in Cameroon

Hematological abnormalities including thrombocytopenia are common in patients living with HIV infection. Patients with HIV infection related thrombocytopenia present generally with only minor bleeding problems. But cases of subdural hematoma are very rare. A 61-year-old female with a history of HIV infection of 9 years' duration presented with a 3-month history of generalized headache associated with visual blurring and anterograde amnesia. There was no history of trauma or fever. She was treated empirically for cerebral toxoplasmosis for 6 weeks without any improvement of the symptoms. One week prior to admission, she developed weakness of the left side of the body. Clinical examination revealed left-sided hemiparesis. Computed tomography scan of the brain showed a 25 mm chronic right frontoparietotemporal subdural hematoma compressing the lateral ventricle with midline shift. There was no appreciable cerebral atrophy. A complete blood count showed leucopenia and thrombocytopenia at 92,000 cells/mm³. Her CD4-positive cell count was 48 cells/mm³ despite receiving combination antiretroviral therapy for 9 years. A complete blood count analysis suggestive of thrombocytopenia should raise suspicion of possibilities of noninfectious focal brain lesions like subdural hematoma amongst HIV infected patients presenting with nonspecific neurological symptoms. This will enable prompt diagnosis and allow early appropriate intervention.

Is Autoimmune Thrombocytopenia Itself the Primary Disease in the Presence of Second Diseases Data from a Long-Term Observation

BACKGROUND

Dependent on the absence or presence of associated diseases, autoimmune thrombocytopenia (ITP) can be classified as primary or secondary form. The manifestation of the associated diseases is not temporally defined and may occur during observation. Thus the question which disease is the primary one remains unanswered.

METHODS

All 386 patients included in this study were treated by a single primary physician between 1996 and 2015 at the Charité Berlin and met current ITP criteria. Medical records and investigations were reviewed to assess diseases associated with ITP.

RESULTS

Initially, the vast majority of patients presented with primary ITP (isolated disease). Based on our findings, ITP was found to be associated with other abnormalities in most cases. These abnormalities included: positive direct antiglobulin test in 49 of 386 tested patients (13%), affections of the thyroid gland in 41 of 386 tested patients (11%), infections in 30 (8%), solid malignancies in 20 (5%) and hematological malignancies in 10 patients (3%), as well as many other miscellaneous diseases. Moreover, of 160 patients who did not receive prior intravenous immunoglobulin treatment, 40 (25%) showed antibody deficiency.

CONCLUSION

In conclusion, the incidence of 'true' ITP as a primary disease is less common than has yet been suggested. Additionally, there is evidence that ITP itself predispose affected subjects toward development of other diseases.

The Centenary of Immune Thrombocytopenia - Part 1: Revising Nomenclature and Pathogenesis

The natural history of the immune thrombocytopenia (ITP) is interesting and intriguing because it traces different steps underlying autoimmune diseases. The review points out the main steps that have accompanied the stages of its history and the consequential changes related to its terminology. ITP is an autoimmune disease resulting from platelet antibody-mediated destruction and impaired megakaryocyte and platelet production. However, research advances highlight that a complex dysregulation of the immune system is involved in the pathogenesis of this condition. The review examines the role of the multiple immune components involved in the autoimmunity process, focusing on the more recent mechanisms, which could be new promising therapeutic targets for ITP patients.

Identification of novel biomarkers in chronic immune thrombocytopenia (ITP) by microarray-based serum protein profiling

The pathological mechanisms underlying the development of immune thrombocytopenia (ITP) are unclear and its diagnosis remains a process of exclusion. Currently, there are no known specific biomarkers for ITP to support differential diagnosis and treatment decisions. Profiling of serum proteins may be valuable for identifying such biomarkers. Sera from 46 patients with primary chronic ITP and 34 healthy blood donors were analysed using a microarray of 755 antibodies. We identified 161 differentially expressed proteins. In addition to oncoproteins and tumour-suppressor proteins, including apoptosis regulator BCL2, breast cancer type 1 susceptibility protein (BRCA1), Fanconi anaemia complementation group C (FANCC) and vascular endothelial growth factor A (VEGFA), we detected six anti-nuclear autoantibodies in a subset of ITP patients: anti-PCNA, anti-SmD, anti-Ro/SSA60, anti-Ro/SSA52, anti-La/SSB and anti-RNPC antibodies. This finding may provide a rational explanation for the association of ITP with malignancies and other autoimmune diseases. While RUNX1mRNA expression in the peripheral blood mononuclear cells (PBMC) of patients was significantly downregulated, an accumulation of RUNX1 protein was observed in the platelets of ITP patients. This may indicate dysregulation of RUNX1 expression in PBMC and megakaryocytes and may lead to an imbalanced immune response and impaired thrombopoiesis. In conclusion, we provide novel insights into the pathogenic mechanisms of ITP that warrant further exploration.

TGFβ-Mediated Downregulation of Thrombopoietin Is Associated With Platelet Decline in Asymptomatic SIV Infection

BACKGROUND

Thrombocytopenia is a known consequence of HIV infection, and decreased production of platelets has been previously implicated in the pathogenesis of platelet decline during asymptomatic infection. Thrombopoietin (THPO) drives platelet production by stimulating the maturation of bone marrow megakaryocytes and can be transcriptionally downregulated by cytokines that are increased during infection such as transforming growth factor β (TGFβ) and platelet factor 4 (pf4).

DESIGN

To determine whether transcriptional downregulation of THPO contributed to decreased platelet production during asymptomatic infection in the simian immunodeficiency virus (SIV)/macaque model of HIV, we compared hepatic THPO mRNA levels to platelet number and megakaryocyte density. To identify potential inhibitory factors that decrease THPO transcription during asymptomatic infection, we measured TGFβ and pf4 plasma levels. To determine whether combined antiretroviral therapy (cART) could correct platelet decline by altering cytokine levels, we measured TGFβ and pf4 in cART-treated SIV-infected macaques and compared these values to cART-untreated SIV-infected macaques.

RESULTS

Hepatic THPO transcription was downregulated during asymptomatic SIV infection concurrent with platelet decline. Hepatic THPO mRNA levels correlated with bone marrow megakaryocyte density. In contrast, plasma TGFβ levels were inversely correlated with hepatic THPO transcription and bone marrow megakaryocyte density. With cART treatment, plasma TGFβ levels and platelet count returned to values similar to those in uninfected macaques.

CONCLUSIONS

TGFβ-mediated downregulation of hepatic THPO may lead to decline in platelet number during asymptomatic SIV infection, and cART may prevent platelet decline by normalizing plasma TGFβ levels.

Resolution of autoimmune thrombocytopenia associated with raltegravir use in an HIV-positive patient

About 10% of the human immunodeficiency virus (HIV) patients show thrombocytopenia. We describe the case of an HIV/HCV-positive patient whose autoimmune thrombocytopenia resolved with the addition of raltegravir to previous highly active antiretroviral therapy (HAART). It is noteworthy that the effect on platelet count appeared to be independent of viral load suppression, which was achieved with previous antiretroviral regimens. In fact, it has been suggested that the positive effect exerted by raltegravir on autoimmune diseases is due to its inhibition on herpes viruses, and hence on activation of endogenous human retroviruses. This consideration, if confirmed, could open new avenues in the treatment of autoimmune thrombocytopenia in the HIV setting.

Immunological HCV-associated thrombocytopenia: short review

Infection with Hepatitis C virus (HCV) is affecting about 3% of the world's population, leading to liver damage, end-stage liver disease, and development of hepatocellular carcinoma, being thus the first indication for liver transplantation in the USA. Apart from the cirrhotic-liver-derived clinical signs and symptoms several conditions with immunological origin can also arise, such as, glomerulonephritis, pulmonary fibrosis, and thrombocytopenia. HCV-related autoimmune thrombocytopenia shows specific pathogenetic characteristics as well as symptoms and signs that differ in severity and frequency from symptoms in patients that are not HCV infected. Aim of this short paper is to estimate the epidemiological characteristics of the disease, to investigate the pathogenesis and clinical manifestation, and to propose treatment strategies according to the pertinent literature.

Mechanism of thrombocytopenia in chronic hepatitis C as evaluated by the immature platelet fraction

INTRODUCTION

Thrombocytopenia occurs frequently in chronic hepatitis C. The mechanism of this association was investigated utilizing the immature platelet fraction (IPF%) as an index of platelet production together with assay of thrombopoietin (TPO).

METHODS

In a cross-sectional study, 47 patients with chronic hepatitis C were studied, 29 with thrombocytopenia and 18 without thrombocytopenia (six patients in each group were on interferon therapy).

RESULTS

IPF% was elevated in the thrombocytopenic compared with the nonthrombocytopenic group (9.0 ± 4.8% vs. 4.7 ± 2.4%, P < 0.001), and an increase in IPF% was significantly associated with thrombocytopenia on multivariable analysis (P < 0.05). Splenomegaly was more common in thrombocytopenic than in nonthrombocytopenic subjects (66% vs. 6%, P < 0.001), and on multivariable analysis, splenomegaly was the factor associated with the highest relative risk of thrombocytopenia (RR = 1.9, P < 0.05). IPF% values were elevated in a similar proportion of thrombocytopenic patients with and without splenomegaly (58% and 60%, respectively). There was no difference in TPO levels between thrombocytopenic and nonthrombocytopenic patients, and TPO levels were not related to the risk of thrombocytopenia on multivariable analysis. Significantly more thrombocytopenic than nonthrombocytopenic subjects had abnormal liver function tests, cirrhosis, and portal hypertension, and a decrease in serum albumin was significantly associated with thrombocytopenia (P < 0.005) on multivariable analysis.

CONCLUSIONS

Factors associated with liver disease in general are associated with thrombocytopenia in chronic hepatitis C. Peripheral platelet destruction or sequestration is the major mechanism for thrombocytopenia, with hypersplenism being an important cause. Low TPO levels were not related to the occurrence of thrombocytopenia in this study.

HIV and SIV Associated Thrombocytopenia: An Expanding Role for Platelets in the Pathogenesis of HIV

Thrombocytopenia is common in HIV and SIV infection, and is often associated with disease progression. HIV and SIV-associated thrombocytopenia arise through multiple mechanisms, including decreased platelet production, increased platelet destruction due to HIV-mimetic anti-platelet antibodies, and increased use of activated platelets. Activated platelets have the potential to contribute to the pathogenesis of HIV and SIV by interacting directly with inflammatory cells and endothelium and by releasing soluble immunomodulatory cytokines.

Portal vein thrombosis as complication of romiplostim treatment in a cirrhotic patient with hepatitis C-associated immune thrombocytopenic purpura

BACKGROUND & AIMS

Thrombopoietin receptor agonists are a new class of compounds licenced for the treatment of immune thrombocytopenic purpura. They are currently being studied for patients with thrombopenia in advanced liver disease or under therapy for hepatitis C. There are indications that the risk for development of portal vein thrombosis in patients with advanced liver cirrhosis might be increased under therapy with thrombopoietin receptor agonists. We report a case of a patient with Child class B liver cirrhosis with concurrent immune thrombocytopenic purpura that developed portal vein thrombosis under therapy with the thrombopoietin receptor agonist romiplostim.

METHODS

A 50-year-old woman with hepatitis C virus associated immune thrombocytopenic purpura and Child class B liver cirrhosis presented in our emergency with rapidly evolving hydropic decompensation and general malaise. For immune thrombocytopenic purpura, the patient was started on the thrombopoietin receptor agonist romiplostim nine months ago.

RESULTS

During hospitalization, the platelet count was measured above 330,000/μl and partial portal vein thrombosis was diagnosed by imaging studies. The thrombotic event was assumed to be associated with the romiplostim treatment for immune thrombocytopenic purpura via excessive elevation of platelet count. After anticoagulation with heparin and cessation of romiplostim treatment, complete recanalisation of the portal vein was achieved.

CONCLUSIONS

We conclude that romiplostim should be used with precaution in patients with hepatitis C-associated immune thrombocytopenic purpura and advanced liver cirrhosis as the risk for thrombotic complications may increase significantly.

Reviewed diagnosis of primary and secondary immune thrombocytopenic purpura in 79 adult patients hospitalized in 2000-2002

Despite the accepted distinction between primary and secondary immune thrombocytopenic purpura (ITP), a systematic analysis of the incidence of secondary ITP is not available. The present study was aimed at verifying the frequency and, consequently, the approximate rates of prevalence and incidence of secondary ITP and analysing its clinical and laboratory characteristics in patients needing ordinary hospital treatment for ITP. The study was based on 79 consecutive, adult ITP patients admitted to three Italian hospitals in 2000-2002. Using data collected in a previous study on the appropriateness of hospital management of ITP, we evaluated the frequency of secondary ITP, with the diagnosis formulated on the basis of new acquisitions, derived its rates of prevalence and incidence, and examined the available clinical and laboratory parameters. At our case review, a diagnosis of secondary ITP could be formulated in 38% of the 79 patients. This frequency was significantly higher than that determined at the time the patients were discharged from hospital (13.9%) (P = 0.000). The derived rates of prevalence and incidence of secondary ITP in the general population were, respectively, 2.3 and 1.23 per 100 000 inhabitants per year. In comparison with patients with primary ITP, those with a secondary form more frequently had spleen enlargement (P = 0.000), hepatomegaly (P = 0.001) and lower haemoglobin values (P = 0.005). The high frequency of secondary ITP must be mainly attributed to the currently available knowledge about the nature of some forms of ITP. Particular contributors to the high frequency were cases secondary to infections and those observed in patients who had undergone bone marrow or solid organ transplantation. Some clinical and laboratory alterations appear to be more frequent in secondary ITP than in primary ITP. However, the importance that the identification of particular forms of ITP, such as those secondary to Helicobacter pylori or hepatitis C virus infections, has on the choice of treatment suggests that these conditions must be ascertained independently of the presence or absence of clinical and laboratory alterations.

DIAGNOSIS AND MANAGEMENT OF THROMBOCYTOPENIA IN PREGNANCY

Platelets are an essential component of the first step in the process of haemostasis, plugging defects in the endothelium and providing a surface for secondary haemostasis to occur, via the coagulation pathway. Platelet aggregation and activation cause granule release of von Willebrand factor, ADP and serotonin, which, in turn, results in recruitment of more platelets to form the platelet plug. This serves to stop the bleeding, and also to activate the coagulation pathway on the surface of the activated platelets, leading to a firm fibrin clot.

Selected biochemical and hematological abnormalities in Nigerians with human immunodeficiency virus and hepatitis C virus coinfection

Background

Liver disease has emerged as a major cause of morbidity and mortality in patients with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) coinfection, now that antiretroviral therapy has become more effective and has prolonged life expectancy in HIV-infected patients. The main objectives of this study were to determine the prevalence of HIV/HCV coinfection and the pattern of hematological and biochemical abnormalities associated with such dual infection.

Methods

In this study, patients with HIV infection (cases) were tested for anti-HCV antibodies. There was a control group made up of apparently healthy individuals who came to hospital for medical examination for various reasons. They also had an anti-HCV antibody test. Those who tested positive for anti-HCV antibodies among the cases and control subjects were further evaluated for hemoglobin concentration, total white cell count, platelet count, and liver function.

Results

One hundred and eighty HIV-infected patients and 180 control subjects participated in the study. The seroprevalence of anti-HCV antibodies in the HIV-infected patients and control subjects were 6.7% and 4.4%, respectively (P = 0.57). Serum total bilirubin, conjugated bilirubin, and alkaline phosphatase were significantly higher in the HIV/HCV coinfected patients compared with their HCV monoinfected counterparts (P = 0.0396, 0.0001, and 0.0016, respectively). The mean hemoglobin, white cell count, platelet count, and CD4+ T lymphocyte count were significantly lower in the HIV/HCV coinfected patients than the HCV monoinfected control group (P = 0.0082, 0.0133, 0.0031, and 0.0001, respectively).

Conclusion

The seroprevalence of anti-HCV antibodies in HIV-infected Nigerian patients is 6.7%. Patients with HIV/HCV coinfection have lower blood counts, higher serum bilirubin, and higher serum alkaline phosphatase compared with patients having HCV monoinfection.

[Pathophysiology of immune thrombocytopenia]

Immune thrombocytopenia is an autoimmune disease characterized by a peripheral destruction of platelets. B lymphocytes play a key role but pathogenesis is more complex, involving humoral and cellular immunity associated with an inappropriate platelet production. In this article, we review the different pathogenic pathways, leading to new therapeutic strategies.

Infectious causes of chronic immune thrombocytopenia

Persistent thrombocytopenia may be the consequence of chronic infections with hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Helicobacter pylori, and should be considered in the differential diagnosis of primary immune thrombocytopenia (ITP). Studies have shown that on diagnosis of infections, treatment of the primary disease often results in substantial improvement or complete recovery of the thrombocytopenia. In patients with thrombocytopenia due to HCV-related chronic liver disease, the use of eltrombopag, a thrombopoietin receptor agonist, normalizes platelet levels, thereby permitting the initiation of antiviral therapy. Antiviral therapy with highly active antiretroviral therapy for HIV has aided in platelet recovery, with a corresponding decrease in circulating viral load. Thrombocytopenia in the absence of other disease symptoms requires screening for H. pylori, especially in countries such as Japan, where there is a high prevalence of the disease and the chances of a platelet response to eradication therapy are high.

International consensus report on the investigation and management of primary immune thrombocytopenia

Previously published guidelines for the diagnosis and management of primary immune thrombocytopenia (ITP) require updating largely due to the introduction of new classes of therapeutic agents, and a greater understanding of the disease pathophysiology. However, treatment-related decisions still remain principally dependent on clinical expertise or patient preference rather than high-quality clinical trial evidence. This consensus document aims to report on new data and provide consensus-based recommendations relating to diagnosis and treatment of ITP in adults, in children, and during pregnancy. The inclusion of summary tables within this document, supported by information tables in the online appendices, is intended to aid in clinical decision making.

Platelet count response to H. pylori treatment in patients with immune thrombocytopenic purpura with and without H. pylori infection: a systematic review

Eradication of H. pylori improves thrombocytopenia in some patients with immune thrombocytopenic purpura by mechanisms that remain obscure. Platelet count responses may occur independently of H. pylori infection as a result of the immune modulating effects of macrolide antimicrobials or the removal of other commensal bacteria. We performed a systematic review of the literature to determine the effect of H. pylori eradication therapy in patients with immune thrombocytopenic purpura by comparing the platelet response in patients who were, and who were not infected with H. pylori. MEDLINE, EMBASE, Cochrane central registry and abstracts from the American Society of Hematology (from 2003) were searched in duplicate and independently without language or age restrictions. Eleven studies, 8 from Japan, were included enrolling 282 patients with immune thrombocytopenic purpura who received eradication therapy; 205 were H. pylori-positive and 77 were H. pylori-negative. The odds of achieving a platelet count response following eradication therapy were 14.5 higher (95% confidence interval 4.2 to 83.0) in patients with H. pylori infection (51.2% vs. 8.8%). No study reported bleeding or quality of life. Adverse events were reported in 12 patients. H. pylori eradication therapy was of little benefit for H. pylori-negative patients. These findings strengthen the causal association between H. pylori infection and immune thrombocytopenia in some patients. Randomized trials are needed to determine the applicability of H. pylori eradication therapy across diverse geographical regions.

Platelet count response to H. pylori treatment in patients with immune thrombocytopenic purpura with and without H. pylori infection: a systematic review

Eradication of H. pylori improves thrombocytopenia in some patients with immune thrombocytopenic purpura by mechanisms that remain obscure. Platelet count responses may occur independently of H. pylori infection as a result of the immune modulating effects of macrolide antimicrobials or the removal of other commensal bacteria. We performed a systematic review of the literature to determine the effect of H. pylori eradication therapy in patients with immune thrombocytopenic purpura by comparing the platelet response in patients who were, and who were not infected with H. pylori. MEDLINE, EMBASE, Cochrane central registry and abstracts from the American Society of Hematology (from 2003) were searched in duplicate and independently without language or age restrictions. Eleven studies, 8 from Japan, were included enrolling 282 patients with immune thrombocytopenic purpura who received eradication therapy; 205 were H. pylori-positive and 77 were H. pylori-negative. The odds of achieving a platelet count response following eradication therapy were 14.5 higher (95% confidence interval 4.2 to 83.0) in patients with H. pylori infection (51.2% vs. 8.8%). No study reported bleeding or quality of life. Adverse events were reported in 12 patients. H. pylori eradication therapy was of little benefit for H. pylori-negative patients. These findings strengthen the causal association between H. pylori infection and immune thrombocytopenia in some patients. Randomized trials are needed to determine the applicability of H. pylori eradication therapy across diverse geographical regions.

Increased prevalence of polyomavirus BK viruria that correlates with thrombocytopenia in patients with systemic lupus erythematosus on intensive immunosuppressive therapy

The prevalence of polyomavirus BK (BKV) reactivation is high in patients with systemic lupus erythematosus (SLE) on long-term immunosuppressants compared to normal population. However, only a few studies are available for the possible correlation of BKV reactivation and clinical manifestations in SLE patients. In the present study, we tried to correlate BKV viruria, clinical manifestations, laboratory findings, and medications in patients with SLE. The urine BKV viral DNA copies were detected from 95 patients with SLE and 32 healthy volunteers by real-time PCR. We found that the prevalence rate of BKV viruria in SLE patients was significantly higher than normal group (71.6% vs. 18.6%, p < 0.001) as well as the urine BKV DNA viral load (4.74 +/- 3.17 vs. 1.08 +/- 2.33 by log scale, p < 0.001). Interestingly, BKV viruria (+) SLE patients had more thrombocytopenic events than BKV viruria ( - ) group (32.4% vs. 3.7%, p = 0.008 after adjustment by age and sex). The patients with BKV viruria DNA copy number >3,200,000/ml exhibited more thrombocytopenia risk than BKV viruria <==3,200,000 copy number/ml or BKV viruria ( - ). The use of potent immunosuppressants may increase BKV viruria. In a refractory thrombocytoponeic case, the add-on of anti-BKV medication, leflunomide 20 mg/day rapidly decreased BKV viruria and recovered platelet counts. In conclusion, our study demonstrated that patients with SLE had higher prevalence rate of BKV reactivation that is correlated with thrombocytopenic episode. Intensive immunosuppressive therapy in SLE may increase the risk of BKV viruria.

Therapeutic strategies for hepatitis- and other infection-related immune thrombocytopenias

Secondary thrombocytopenia may result from autoimmune diseases, lymphoproliferative disorders, infections, myelodysplastic syndromes, common variable immunodeficiency, agammaglobulinemia, hypogammaglobulinemia, immunoglobulin A deficiency, and drugs. The presence of thrombocytopenia may result from chronic infections with hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Helicobacter pylori and should be considered in the differential diagnosis of immune thrombocytopenic purpura (ITP). Studies have shown that upon diagnosis of infections, treatment of the primary disease allows for stabilization of platelet counts. Antiviral therapy with highly active antiretroviral therapy (HAART) for HIV has aided in platelet recovery with a corresponding decrease in circulating viral load. In some cases, the use of a thrombopoietin (TPO) agonist, eltrombopag, normalizes platelet levels in patients with these infections. Thrombocytopenia in the absence of other disease symptoms requires screening for H pylori, especially in regions where there is a high prevalence of the disease, such as in Japan, and in cases where platelets have normalized following eradication therapy. In other regions where these infections are not prevalent, such testing is controversial.

The ITP syndrome: pathogenic and clinical diversity

Immune thrombocytopenia (ITP) is mediated by platelet autoantibodies that accelerate platelet destruction and inhibit their production. Most cases are considered idiopathic, whereas others are secondary to coexisting conditions. Insights from secondary forms suggest that the proclivity to develop platelet-reactive antibodies arises through diverse mechanisms. Variability in natural history and response to therapy suggests that primary ITP is also heterogeneous. Certain cases may be secondary to persistent, sometimes inapparent, infections, accompanied by coexisting antibodies that influence outcome. Alternatively, underlying immune deficiencies may emerge. In addition, environmental and genetic factors may impact platelet turnover, propensity to bleed, and response to ITP-directed therapy. We review the pathophysiology of several common secondary forms of ITP. We suggest that primary ITP is also best thought of as an autoimmune syndrome. Better understanding of pathogenesis and tolerance checkpoint defects leading to autoantibody formation may facilitate patient-specific approaches to diagnosis and management.

Severe autoimmune cytopenias in treatment-naive hepatitis C virus infection: clinical description of 16 cases

OBJECTIVE

To describe the prevalence, main characteristics, and treatment of severe autoimmune cytopenias [autoimmune hemolytic anemia (AIHA), autoimmune thrombocytopenic purpura (AITP)] in patients with chronic hepatitis C virus (HCV) infection.

METHODS

Retrospective chart review of patients with chronic HCV infection seen at our institution. Two additional departments contributed eight more patients to assess therapy of HCV-related autoimmune cytopenias.

RESULTS

Eight patients (seven AITP, one AIHA) fulfilled the inclusion criteria in our population of 4345 HCV-infected patients. The number of patients with AITP was much greater than would be expected by chance (P<0.0001). Patients with HCV-related AITP were older and demonstrated more immunological markers than a group of 40 controls. Eight additional patients (six AITP, two Evans syndrome) were included. We only assessed the response for AITP patients because of the single case of AIHA. Patients with AITP had a poor response to initial corticosteroids [one complete response (CR), three partial response (PR), and four failures]. Intravenous immunoglobulins led to transient efficacy in three of four patients. In second-line therapy, five of seven patients responded to splenectomy. Rituximab proved effective in increasing platelets in two patients. Of eight patients treated with antiviral therapy (IFN-alpha+/-ribavirin), five responded (three CR, two PR).

CONCLUSION

AITP occurs more commonly in patients with chronic HCV infection than would be expected by chance. HCV-positive AITP requires a treatment strategy different from that used in HCV-negative AITP. On the basis of the results from our study and a literature analysis, we propose an algorithm for treatment of severe HCV-related autoimmune cytopenias.

Pathobiology of secondary immune thrombocytopenia

Primary immune thrombocytopenic purpura (ITP) remains a diagnosis of exclusion both from nonimmune causes of thrombocytopenia and immune thrombocytopenia that develops in the context of other disorders (secondary immune thrombocytopenia). The pathobiology, natural history, and response to therapy of the diverse causes of secondary ITP differ from each other and from primary ITP, so accurate diagnosis is essential. Immune thrombocytopenia can be secondary to medications or to a concurrent disease, such as an autoimmune condition (eg, systemic lupus erythematosus [SLE], antiphospholipid antibody syndrome [APS], immune thyroid disease, or Evans syndrome), a lymphoproliferative disease (eg, chronic lymphocytic leukemia or large granular T-lymphocyte lymphocytic leukemia), or chronic infection, eg, with Helicobacter pylori, human immunodeficiency virus (HIV), or hepatitis C virus (HCV). Response to infection may generate antibodies that cross-react with platelet antigens (HIV, H pylori) or immune complexes that bind to platelet Fcgamma receptors (HCV), and platelet production may be impaired by infection of megakaryocyte (MK) bone marrow-dependent progenitor cells (HCV and HIV), decreased production of thrombopoietin (TPO), and splenic sequestration of platelets secondary to portal hypertension (HCV). Sudden and severe onset of thrombocytopenia has been observed in children after vaccination for measles, mumps, and rubella or natural viral infections, including Epstein-Barr virus, cytomegalovirus, and varicella zoster virus. This thrombocytopenia may be caused by cross-reacting antibodies and closely mimics acute ITP of childhood. Proper diagnosis and treatment of the underlying disorder, where necessary, play an important role in patient management.

Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group

Diagnosis and management of immune thrombocytopenic purpura (ITP) remain largely dependent on clinical expertise and observations more than on evidence derived from clinical trials of high scientific quality. One major obstacle to the implementation of such studies and in producing reliable meta-analyses of existing data is a lack of consensus on standardized critical definitions, outcome criteria, and terminology. Moreover, the demand for comparative clinical trials has dramatically increased since the introduction of new classes of therapeutic agents, such as thrombopoietin receptor agonists, and innovative treatment modalities, such as anti-CD 20 antibodies. To overcome the present heterogeneity, an International Working Group of recognized expert clinicians convened a 2-day structured meeting (the Vicenza Consensus Conference) to define standard terminology and definitions for primary ITP and its different phases and criteria for the grading of severity, and clinically meaningful outcomes and response. These consensus criteria and definitions could be used by investigational clinical trials or cohort studies. Adoption of these recommendations would serve to improve communication among investigators, to enhance comparability among clinical trials, to facilitate meta-analyses and development of therapeutic guidelines, and to provide a standardized framework for regulatory agencies.

Viral-Associated Immune Thrombocytopenic Purpura

Chronic immune thrombocytopenic purpura (CITP) is a diagnosis of exclusion that occurs either de novo or secondary to other underlying disorders. Chronic infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are now well-characterized causes of CITP. Between 6% and 15% of patients infected with HIV may develop thrombocytopenia. Patients with CITP with risk factors for HIV infection should be screened for the virus. Treatment of HIV-related CITP should be directed toward antiviral therapy with highly active antiretroviral therapy (HAART) regimens. Hepatitis C viral infection can also be associated with chronic thrombocytopenia, even in the absence of overt liver disease. While HCV-related thrombocytopenia is typically less severe than primary CITP, affected patients are at greater risk of major bleeding. Sustained suppression of HCV virus with interferon-ribavirin therapy can improve platelet counts. Screening for HCV infection should be considered in patients with ITP with risk factors for infection, from regions with high rates of infection or in patients with unexplained mild elevations of liver enzymes.

Helicobacter pylori and Chronic ITP

Eradication of Helicobacter pylori infection has been variably associated with a platelet response in patients with immune thrombocytopenic purpura (ITP). Responses occur in approximately half of ITP patients infected with this bacterium, more frequently in Japan and Italy than in other countries. For those with severe ITP (platelet count<30x10(9)/L) and a long duration of disease, eradication therapy seems to be less effective. Despite extensive efforts, distinctive clinical features and factors predicting the response to eradication therapy have not been consistently identified. There is no established mechanism to explain how H pylori could be implicated in the pathogenesis of an immune-mediated platelet destruction. Several theories have been proposed to explain the platelet response to anti-H pylori therapy, including molecular mimicry, platelet aggregation, and the induction of a Th1 phenotype that favors the onset and/or persistence of ITP. The role of bacterium-related factors, such as the CagA (cytotoxin-associated gene A) protein, are still under investigation. Eradication therapy is simple and inexpensive, with limited toxicity and the advantage of avoiding long-term immunosuppressive treatment for those who respond. Although the evidence and follow-up are limited, it appears reasonable to routinely screen patients with ITP for H pylori, particularly in those populations with a high background prevalence of H pylori infection.