Infectious causes of chronic immune thrombocytopenia

Clinical features and treatment effect of HIV-associated immune thrombocytopenia-single center Ten-Years data summary

Thrombocytopenia represents one of the most prevalent hematologic complications observed in patients infected with the human immunodeficiency virus (HIV). In this study, we sought to analyze the clinical characteristics and treatment outcomes of patients with coexisting HIV and thrombocytopenia. Specifically, we retrospectively examined the medical records of 45 patients diagnosed with HIV/AIDS and thrombocytopenia at the Yunnan Infectious Diseases Specialist Hospital between January 2010 and December 2020, all of whom received highly active antiretroviral therapy (HAART) with/without glucocorticoids. The median follow-up period was 79 days, ranging between 14 and 368 days, the total platelet count was higher after receiving treatment than before (Z = -5.662, P < .001). Among the cohort, 27 patients (60.0%) responded to treatment, with 12 patients (44.44%) experiencing relapse during the follow-up period. The response rate (80.00%) of newly diagnosed ITP were significantly higher than of persistent ITP (28.57%) and chronic ITP (38.46%) (\x ² = 9.560, P = .008) and the relapse rate of the newly diagnosed ITP (30.00%) was significantly lower than the persistent ITP and chronic ITP (100.00%, 80.00%) (\x² = 6.750, P = .034). Notably, we found that the number of CD4+ T cells, duration of HIV infection, selection of HAART and type of glucocorticoids administered displayed no statistically significant effect on platelet count, treatment response, or relapse rate. However, we observed a significant decrease in platelet count in hepatitis C virus-positive individuals coinfected with HIV compared to those with HIV alone (Z = -2.855, P = .003). Our findings suggest that patients diagnosed with HIV and thrombocytopenia exhibit a low response rate to treatment and have an increased likelihood of relapse.

Severe immune thrombocytopenia following diphtheria, tetanus, pertussis and polio vaccination in a 36-year-old Caucasian woman: a case report

Background

Immune thrombocytopenia (ITP) is a rare autoimmune disorder characterized by low platelet counts and increased bleeding risk. The disease may be induced by other disorders, including malignancies, autoimmune diseases, infectious agents or drugs. However, ITP has also been described following vaccinations, such as the measles–mumps–rubella vaccination. In rare cases, ITP may occur in children who received a DTaP-IP (diphtheria, tetanus, acellular pertussis vaccine and inactivated poliovirus) vaccine. Hereinafter, we report the first well-documented cases of ITP in an adult patient in the temporal context of a DTaP-IP vaccination.

Case presentation

This case report attempts to capture the life-threatening picture of a 36-year-old otherwise healthy Caucasian woman with newly diagnosed severe immune thrombocytopenia in the temporal context of a DTaP-IP vaccination. Four days after receiving the vaccine, the women presented to her primary care physician with malaise, fever and recurrent epistaxis. Clinical examination revealed oral petechiae, ecchymoses, and non-palpable petechiae on both legs. The patient was immediately referred to a local hematology unit where she developed hematuria and an intestinal bleeding (WHO Bleeding Grade III) requiring multiple transfusions. After receiving oral corticosteroids and intravenous immunoglobulins, her platelets gradually recovered. Common causes of secondary ITP were ruled out by laboratory investigations, bone marrow and peripheral blood examinations. This raises the possibility of a (secondary) vaccination-associated thrombocytopenia. To the best of our knowledge, this is the first well-documented case of a DTaP-IP vaccination-related ITP in an adult patient in the English literature.

Conclusion

Although a causal connection between both entities may not be established, we would like to raise awareness in clinicians that ITP following DTaP-IP vaccinations is potentially not limited to children, but may also occur in adults. Users of DTaP-IP booster vaccines should be alert of the possibility of such adverse reactions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00686-z.

The molecular basis of immune-based platelet disorders

Platelets have a predominant role in haemostasis, the maintenance of blood volume and emerging roles as innate immune cells, in wound healing and in inflammatory responses. Platelets express receptors that are important for platelet adhesion, aggregation, participation in inflammatory responses, and for triggering degranulation and enhancing thrombin generation. They carry a cargo of granules bearing enzymes, adhesion molecules, growth factors and cytokines, and have the ability to generate reactive oxygen species. The platelet is at the frontline of a host of cellular responses to invading pathogens, injury, and infection. Perhaps because of this intrinsic responsibility of a platelet to rapidly respond to thrombotic, pathological and immunological factors as part of their infantry role; platelets are susceptible to targeted attack by the adaptive immune system. Such attacks are often transitory but result in aberrant platelet activation as well as significant loss of platelet numbers and platelet function, paradoxically leading to elevated risks of both thrombosis and bleeding. Here, we discuss the main molecular events underlying immune-based platelet disorders with specific focus on events occurring at the platelet surface leading to activation and clearance.

Insights on chronic immune thrombocytopenia pathogenesis: A bench to bedside update

Immune thrombocytopenia (ITP) is a heterogeneous disease with an unpredictable course. Chronicity can develop in up to two-thirds of adults and 20-25% of children, representing a significant burden on patients' quality of life. Despite acceptable responses to treatment, precise etiology and pathophysiology phenomena driving evolution to chronicity remain undefined. We analyzed reported risk factors for chronic ITP and associated them with proposed underlying mechanisms in its pathogenesis, including bone marrow (BM) microenvironment disturbances, clinical features, and immunological markers. Their understanding has diagnostic implications, such as screening for the presence of specific antibodies or BM examination employing molecular tools, which could help predict prognosis and recognize main pathogenic pathways in each patient. Identifying these underlying mechanisms could guide the use of personalized therapies such as all-trans retinoic acid, mTor inhibitors, FcRn inhibitors, oseltamivir, and others. Further research should lead to tailored treatments and chronic course prevention, improving patients' quality of life.

Impact of eradication therapy of Helicobacter pylori in children with chronic immune thrombocytopenic purpura

Background

Although some investigators have confirmed the association between H. pylori and chronic ITP in adults, studies in pediatric patients are still few and have produced conflicting results. The study was carried out to detect the prevalence of H. pylori among chronic ITP children and to investigate the impact of treatment of H. pylori infection on platelet count response.

Results

The prevalence of H. pylori in chronic ITP children was 63%. The platelet count was statistically significantly higher among H. pylori stool antigen (HpSA)-negative children. A significant difference was reported in which platelet count increased from 70.55 ± 4.788 million/μL before H. pylori eradication therapy to 110.78 ± 15.128 million/μL after therapy.

Conclusion

We concluded that H. pylori eradication therapy was effective in increasing platelet count in H. pylori-positive chronic ITP patients.

Low arterial oxygen partial pressure induces pulmonary thrombocytopenia in patients and a mouse model

BACKGROUND

Recent basic studies demonstrate that the lung is a primary organ of platelet biogenesis. However, whether the pathophysiological state of the lung affect the platelets is little known. We aim to investigate the incidence of thrombocytopenia in patients with pulmonary infection (PIN) and risk factors associated with pulmonary thrombocytopenia.

METHODS

In total, 11,941 patients with pulmonary infection (PIN) were enrolled, and patients with other three infectious diseases were collected as controls. The incidence of thrombocytopenia was compared, and the risk factors associated with thrombocytopenia in PIN patients were investigated by multivariate analysis. To explore the mechanism of thrombocytopenia, hypoxic model was constructed. Blood platelet counts from the angular vein (PLTs), left ventricle (PLT_post) and right ventricle (PLT_pre) were determined. Megakaryocytes identified by anti-CD41 antibody were detected through flow cytometry and immunofluorescence.

RESULTS

The incidence of thrombocytopenia in PIN was higher than that in other three infectious diseases (9.8% vs. 6.4% ~ 5.0%, P < 0.001). Low arterial oxygen partial pressure (PaO₂) was an important risk factor for thrombocytopenia (OR = 0.88; P < 0.001). In a hypoxic mouse model, PLTs decreased (518.38 ± 127.92 vs 840.75 ± 77.30, P < 0.05), which showed that low PaO₂ induced thrombocytopenia. The difference between the PLT_post and PLT_pre (∆PLT_post-pre), representing the production of platelets in the lungs, was significantly attenuated in hypoxic mice when compared with normoxic mice (F = 25.47, P < 0.05). Additionally, proportions of CD41-positive megakaryocytes in the lungs, marrow, spleen all decreased in hypoxic mice.

CONCLUSION

There is a high incidence for thrombocytopenia in PIN patients. Low PaO₂-induced thrombocytopenia is associated with impaired generation of platelet in the lungs.

Thrombocytopenia Secondary to Herpes Simplex Virus-2 Infection Successfully Treated by Acyclovir

Thrombocytopenia is a common clinical condition associated with a wide variety of clinical conditions including infections, malignancy, medications, liver disorder, and autoimmune conditions, etc. The association between thrombocytopenia and herpes simplex virus (HSV) is reported only once in a case report dating back to 1978. We report a case of a 66-year-old female with generalized weakness, mechanical fall, genital ulcerations, and breast fold and genital area skin redness, warmth, and mild tenderness. Initial labs showed mild leukocytosis, normal platelet count, mild lactic acidosis, and urine analysis suggestive of urinary tract infection. The patient was started on broad-spectrum antibiotics. During the course of hospitalization, the patient developed severe thrombocytopenia with platelet counts dropping less than 40000/μL (normal range: 150,000-450,000/μL), and genital pain and ulceration worsened. The genital swab was sent which came back positive for the HSV-2 virus. Soon after the start of acyclovir for HSV-2 infection, the genital pain and ulceration improved and platelet counts gradually increased to 157,000/μL. Other causes of thrombocytopenia such as sepsis, heparin-induced thrombocytopenia, consumptive coagulopathy, medication-induced thrombocytopenia, immune thrombocytopenia, and thrombotic thrombocytopenic purpura were ruled out.

A case of immune thrombocytopenia due to miliary tuberculosis effectively treated with eltrombopag

An 80-year-old woman was diagnosed with miliary tuberculosis. Laboratory findings showed marked thrombocytopenia (3000/μl). Immune thrombocytopenia (ITP) was diagnosed because platelet transfusion was ineffective, and bone marrow puncture demonstrated a normal number of megakaryocytes. Anti-tuberculosis treatment was started promptly, followed by prednisolone 20 mg. However, the platelet count did not increase. The effect of high-dose intravenous immunoglobulin was temporary. She was not responded to prednisolone, and eltrombopag 12.5 mg was added. The eltrombopag dose was increased by 12.5 mg every two weeks. When the eltrombopag dose reached 50 mg, the thrombocytopenia improved sufficiently (44,000/μl). She didn't have any severe bleeding and thrombotic complications. The treatment of tuberculosis went well and there was no side effect of anti-tuberculosis treatment. Eltrombopag can be a useful treatment for ITP due to tuberculosis.

Incidence and Outcome of Severe and Nonsevere Thrombocytopenia Associated With Zika Virus Infection-Puerto Rico, 2016

Background

Zika virus (ZIKV) infection has been associated with severe thrombocytopenia. We describe the incidence, clinical manifestations, and outcomes of patients with ZIKV infection and thrombocytopenia.

Methods

We reviewed medical records of patients with ZIKV infection and thrombocytopenia (platelet count <100 ×10⁹ cells/L) in Puerto Rico during 2016. Severe thrombocytopenia was defined by platelet count <20 ×10⁹/L or a platelet count <50 ×10⁹/L and treatment for immune thrombocytopenia (ITP).

Results

Of 37 878 patients with ZIKV infection, 47 (0.1%) had thrombocytopenia in the absence of an alternative etiology (1.4 cases/100 000 population), including 12 with severe thrombocytopenia. Most patients with thrombocytopenia were adult (77%) and male (53%). Platelet nadir occurred a median (range) of 6 (1-16) and 5 (0-34) days after symptom onset for patients with severe and nonsevere thrombocytopenia, respectively. Among patients with severe thrombocytopenia, all had bleeding, 33% were admitted to the intensive care unit, and 8% died; 50% were treated for ITP. Among 5 patients with severe thrombocytopenia who received intravenous immunoglobulin, the median platelet count increase (range) was 112 (65-202) ×10⁹/L. In contrast, among 4 patients who received platelet transfusion, the median increase in platelet count (range) was 8.5 (-6 to 52) ×10⁹/L.

Conclusions

Patients with severe thrombocytopenia and ZIKV infection experienced prominent acute morbidity. Consistent with recommended management, administration of ITP treatments to such patients may be more efficacious than platelet transfusion in resolving thrombocytopenia. Severe thrombocytopenia should be considered a rare outcome of ZIKV infection.

Helicobacter pylori Eradication in Idiopathic Thrombocytopenic Purpura: A Meta-Analysis of Randomized Trials

Objective

Several recent reviews of published studies have shown that the eradication of H. pylori infection in patients with ITP improved thrombocytopenia in about half of the cases. However, most included studies were observational case series. We performed the first meta-analysis of randomized trials to gain a better insight into the effect of H. pylori eradication in ITP patients.

Methods

A systematic computerized search of the electronic databases including PubMed, EMBASE, Google Scholar, and Cochrane Library (up to December 2017) was conducted.

Results

From six studies, a total of 241 patients (125 in eradication group and 116 in control group) were included in the meta-analysis. Patients in the eradication group showed significantly higher overall platelet response rate than those in the control group (odds ratio = 1.93, 95% confidence interval: 1.01–3.71, P = 0.05). In the subgroup analysis, however, children in the eradication group failed to show statistically better response rate than those in the noneradication group (odds ratio = 1.80, 95% confidence interval: 0.88–3.65, P = 0.11).

Conclusions

This meta-analysis indicates that H. pylori eradication has a significant therapeutic effect in patients with ITP. Considering the intrinsic limits in the design and sample size of the included studies, however, large randomized controlled trials are warranted to validate the therapeutic impact of H. pylori eradication in adults as well as children with ITP.

Immune thrombocytopenic purpura might be an early hematologic manifestation of undiagnosed human immunodeficiency virus infection

Little research focuses on the association between immune thrombocytopenic purpura and human immunodeficiency virus infection in Taiwan. This study investigated whether immune thrombocytopenic purpura might be an early hematologic manifestation of undiagnosed human immunodeficiency virus infection in Taiwan. We conducted a retrospective population-based cohort study using data of individuals enrolled in Taiwan National Health Insurance Program. There were 5472 subjects aged 1-84 years with a new diagnosis of immune thrombocytopenic purpura as the purpura group since 1998-2010 and 21,887 sex-matched and age-matched, randomly selected subjects without immune thrombocytopenic purpura as the non-purpura group. The incidence of human immunodeficiency virus infection at the end of 2011 was measured in both groups. We used the multivariable Cox proportional hazards regression model to measure the hazard ratio and 95 % confidence interval (CI) for the association between immune thrombocytopenic purpura and human immunodeficiency virus infection. The overall incidence of human immunodeficiency virus infection was 6.47-fold higher in the purpura group than that in the non-purpura group (3.78 vs. 0.58 per 10,000 person-years, 95 % CI 5.83-7.18). After controlling for potential confounding factors, the adjusted HR of human immunodeficiency virus infection was 6.3 (95 % CI 2.58-15.4) for the purpura group, as compared with the non-purpura group. We conclude that individuals with immune thrombocytopenic purpura are 6.47-fold more likely to have human immunodeficiency virus infection than those without immune thrombocytopenic purpura. We suggest not all patients, but only those who have risk factors for human immunodeficiency virus infection should receive testing for undiagnosed human immunodeficiency virus infection when they develop immune thrombocytopenic purpura.

Thrombocytopenia and infections

INTRODUCTION

Acquired thrombocytopenia recognizes a myriad of causes. Among these, infectious diseases play a relevant role since a low platelet count is commonplace along with other abnormal laboratory data. Areas covered: This narrative review, after a brief presentation of the possible pathogenic mechanisms, is focused on the most prevalent infections associated with thrombocytopenia, namely those attributable to hepatitis C virus (HCV), human immunodeficiency virus (HIV) and Helicobacter pylori. Expert commentary: An underlying HCV or HIV infection should always be suspected in patients at risk who present with isolated thrombocytopenia. The eradication of Helicobacter pylori is advisable in infected patients with secondary immune thrombocytopenia, because this will increase the platelet count in a substantial number of cases, thus avoiding more aggressive and prolonged treatments.

Thrombopoietic cytokines in patients with hepatitis C virus-associated immune thrombocytopenia

OBJECTIVES

Complex and multiple mechanisms are involved in the etiology of Hepatitis C virus-associated immune thrombocytopenia (HCV-ITP). Many hematopoietic growth factors affect the thrombopoiesis. The aim of this study was to clarify the interaction of the thrombopoietic factors in patients with HCV-ITP.

METHODS

We selected 33 patients with HCV-ITP and 17 normal individuals. We compare serum interleukin (IL)-3, IL-6, IL-11, thrombopoietin (Tpo), stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor-α (TNFα), and spleen size between these two groups.

RESULTS

Our study shows that Tpo, IL-6, and TNFα significantly increased in patients with HCV-ITP compared to the normal population (Tpo:122.577 vs. 40.602; IL-6: 2.175 vs. 0.943; TNFα: 2.460 vs. 1.322). IL-11 was significantly lower in the HCV-ITP group (10.829 vs. 15.042). HCV-ITP patients had a higher spleen index (21.121 vs 13.498, P = 0.003). According to regression analysis and multiple linear regression analysis, only IL-11 had a significantly positive correlation with platelet count, while TNFα showed a negative correlation.

DISCUSSIONS

Tpo and IL-6 increased in patients with HCV-ITP, suggesting a positive feedback of low platelet count. TNFα-associated immune response is suspected to have an impact on low platelet count. IL-11 is assumed to directly affect thrombopoiesis.

CONCLUSIONS

This study is the most comprehensive study to evaluate the interaction between platelet count and the important thrombopoetic factors in patients with HCV-ITP. The thrombopoietic factors clearly play an important role in HCV-ITP.

Impact of the highly active antiretroviral therapy era on the epidemiology of primary HIV-associated thrombocytopenia

BACKGROUND

Primary HIV-associated thrombocytopenia (PHAT) typically improves with highly active antiretroviral therapy (HAART); however, cases continue to occur. Data comparing the epidemiology of PHAT between the pre-HAART and HAART eras are limited. We retrospectively examined the incidence of PHAT over 28 years in the US Military HIV Natural History Study (NHS) from 1986 to 2013.

RESULTS

Subjects had a nadir platelet count <100 × 10(9)/l with no other identifiable cause. Time periods were categorized as pre-HAART (1986-1995), early HAART (1996-2001), and later HAART (2002-2013). Incidence, demographic data, and CD4 count were compared across the three eras. A generalized estimating equations model was used to assess any association of platelet count and HIV viral load in cases diagnosed during the HAART eras. 218 participants met the case definition. 86.2 % of cases occurred prior to 2002. The incidence of PHAT per 1000 person-years of follow-up was 16.3, 4.6, and 1.9 during pre-HAART, early HAART and later HAART eras respectively. CD4 cell counts were significantly higher in the HAART eras at the time of thrombocytopenia (p < 0.001). Of patients diagnosed after 1996, 96.4 % were viremic within six months preceding the platelet nadir and over half were antiretroviral naïve. Viral load (per log10 copies/ml) inversely correlated with platelet count throughout the HAART eras (p < 0.0001).

CONCLUSIONS

The incidence of PHAT has markedly decreased in the HAART era. However, viremic individuals, including those with healthy CD4 cell counts, may be at risk. Achieving viral suppression as early as possible may decrease the incidence further.

Prevalence of thrombocytopenia among Chinese adult antiretroviral-naïve HIV-positive patients

BACKGROUND

The prevalence of thrombocytopenia among Chinese antiretroviral therapy (ART)-naïve HIV-infected adults has not been well-described. The aim of this study was to investigate the prevalence and associated risk factors of thrombocytopenia among Chinese ART-naïve HIV-infected adults.

METHODS

We performed a cross-sectional study of Chinese adult ART-naïve HIV-infected patients from September 2005 through August 2014. Socio-demographic variables and laboratory results including platelets, CD4+ cell count, and viral load were obtained from medical records. Factors and outcomes associated with thrombocytopenia were assessed using logistic regression.

RESULTS

A total of 1730 adult ART-naïve HIV-infected patients was included. The mean age was 38 years. The prevalence of thrombocytopenia was 4.5%. There were significant differences in the prevalence of thrombocytopenia between patients <30 years of age (2.8%) and 30-39 years (4.0%) compared with patients greater than 50 years (7.0%) (P = 0.006 and P = 0.044, respectively). The prevalence of thrombocytopenia was also significantly different between patients with CD4+ counts of 200-349 cells/mm 3 (3.3%) and >350 cells/mm 3 (2.8%) compared with patients with CD4+ counts of 50-199 cells/mm 3 (7.1%) (P = 0.002 and P = 0.005, respectively). The prevalence of thrombocytopenia was significantly different by hepatitis C virus antibody (HCV-Ab) seropositivity (10.2% for HCV-Ab positive vs. 3.9% for HCV-Ab negative, P = 0.001). We observed differences in prevalence of thrombocytopenia by mode of transmission of HIV infection: Blood transmission (10.7%) versus men who have sex with men (3.9%) (P = 0.002) and versus heterosexual transmission (3.9%) (P = 0.001). In binary logistic regression analyses, age ≥ 50 years, HCV-Ab positivity and having a CD4+ cell count of 50-199 cells/mm 3 were significantly associated with thrombocytopenia with adjusted odds ratio of 2.482 (95% confidence interval [CI]: 1.167, 5.281, P = 0.018), 2.091 (95% CI: 1.078, 4.055, P = 0.029) and 2.259 (95% CI: 1.028, 4.962, P = 0.042), respectively.

CONCLUSIONS

Thrombocytopenia is not common among adult ART-naïve HIV-infected patients in China. Older age (age over 50 years), HCV-Ab positivity and lower CD4+ cell count are associated with an increased risk of thrombocytopenia. Therefore, early diagnosis and treatment of thrombocytopenia in these patients are necessary.

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in ‘natural host’ species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.

The HIV-1/AIDS pandemic is the result of cross-species transmission of simian immunodeficiency virus (SIVcpz) from chimpanzees to humans. Many African primates are infected with SIV, but those studied in captivity generally do not develop disease. However, wild chimpanzees infected with SIVcpz are at increased risk of death and may develop an AIDS-like disease. It has therefore been suggested that the viral features which SIVcpz and HIV-1 share, that differentiate them from other species’ SIV, may be critical in the development of disease in both humans and chimpanzees. Here, we present a long-term follow-up of 7 SIVcpz infected chimpanzees, housed in primate centres in the US and Europe, under similar conditions to other studied models. These animals did not develop an AIDS-like disease, after up to 25 years of infection, and showed features similar to other species where disease rarely develops, such as limited immune activation in the blood. However, they also had significantly reduced CD4+ T-cells and disruption to the secondary lymphoid tissues, normally associated with pathogenic primate lentiviral infections. Thus, while SIVcpz infection of chimpanzees shares features of both pathogenic and non-pathogenic infections, disease has not developed in captivity.

Immune thrombocytopaenic purpura: an autoimmune cross-link between infections and vaccines

Immune thrombocytopaenic purpura (ITP) is an autoimmune systemic disease detectable by the presence of low blood platelets count (<10(5)/µl) and the production of autoantibodies against glycoproteins expressed on the platelet surface. The clinical course is often acute, and life-threatening events may occur especially in children, with 52% of paediatric patients recovering either spontaneously or after treatment. A chronic ITP evolution is observed in 64% of adults, of whom 12% will develop an overlapping autoimmune disease. Several microbial agents such as CagA-positive Helicobacter pylori or Candida albicans and a number of viruses including CMV, EBV or HIV can potentially trigger ITP through molecular mimicry. Moreover, ITP improves after treatment of the underlying infection. Similarly, vaccines such as MMR may prompt ITP (IRR 5.48, 1.61-18.64, p < 0.006). Early recognition of the underlying microbial trigger and the removal of modifiable aetiopathogenetic factors should be integrated as a complementary treatment strategy in all patients who do not readily improve with standard ITP care.

Immune thrombocytopenia in adults

Immune thrombocytopenia is an autoimmune disease resulting in the destruction of platelets. It is classified as acute, thrombocytopenia occurring for < 6 mo and usually resolving spontaneously, and chronic, lasting > 6 mo and requiring therapy to improve the thrombocytopenia. The underlying defects leading to autoantibody production are unknown. Molecular mimicry appears to play a role in the development of self-reactive platelet antibodies after vaccination and certain viral infections. Platelet life span is reduced as a consequence of antibody-mediated clearance by tissue macrophages in essentially all patients. Diagnosis is based on the exclusion of the other causes of thrombocytopenia. Steroid is the first choice of the treatment, often followed by splenectomy in unresponsive cases. Intravenous immunoglobulin, anti-Rho(D) immune globulin, azathioprine, cyclosporine A, cyclophosphamide, danazol, dapsone, mycophenolate mofetil, rituximab, thrombopoietin receptor agonists and vinca alkaloids are other choices of treatment.

Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a rare autoimmune disorder with an incidence of 3 to 5 per 100 000 individuals. In children, the disease is self-limited and is most commonly virus related (acute ITP) whereas in adults, the disease is typically chronic. The age distribution of adult ITP displays 2 peaks; the first in younger adults aged 18 to 40 with a female predominance and the second in people aged older than 60 with men and women affected equally. Our approach to ITP has evolved over the past several years: there has been a change in nomenclature and ITP now denotes “immune thrombocytopenia” (the “I” no longer denoting “idiopathic”) and “purpura” no longer features in the name of the disease; new insights into the pathogenesis of ITP have revealed the importance of impaired megakaryocytopoiesis in the condition; underlying mechanisms of secondary ITP have been elucidated and finally novel thrombopoietic agents have been shown to be effective in the treatment of ITP in randomized clinical trials. In this article, we review important recent advances in the pathogenesis and treatment of ITP.

Hematologic manifestations of liver disease

The liver plays a key role in both protein biosynthesis and lipid metabolism. As a result, hepatic synthetic dysfunction can have adverse effects on both cellular and soluble components of blood. Anemia may occur due to the hemolysis of acanthocytes (spur cells), which is ultimately due to abnormal lipid composition of the red blood cell membrane. Thrombocytopenia may result from several different mechanisms. Cytopenias also may be a consequence of hypersplenism. The liver is the primary site for synthesis of most procoagulant and anticoagulant proteins. The coagulopathy of liver disease is therefore complex. Early in the course of liver disease, thrombocytopenia and a coagulopathy associated with a prothrombotic state are not uncommon, whereas with more advanced disease pancytopenia and coagulopathy associated with hemorrhage become manifest. Fresh frozen plasma and adjuncts to hemostasis may be used as temporizing measures in bleeding patients. However, definitive management of many of the defects due to fulminant hepatic failure requires liver transplantation.

Helicobacter pylori infection and extragastric disorders in children: a critical update

Helicobacter pylori (H. pylori) is a highly prevalent, serious and chronic infection that has been associated causally with a diverse spectrum of extragastric disorders including iron deficiency anemia, chronic idiopathic thrombocytopenic purpura, growth retardation, and diabetes mellitus. The inverse relation of H. pylori prevalence and the increase in allergies, as reported from epidemiological studies, has stimulated research for elucidating potential underlying pathophysiological mechanisms. Although H. pylori is most frequently acquired during childhood in both developed and developing countries, clinicians are less familiar with the pediatric literature in the field. A better understanding of the H. pylori disease spectrum in childhood should lead to clearer recommendations about testing for and treating H. pylori infection in children who are more likely to develop clinical sequelae. A further clinical challenge is whether the progressive decrease of H. pylori in the last decades, abetted by modern clinical practices, may have other health consequences.

Helicobacter pylori-associated immune thrombocytopenia: Clinical features and pathogenic mechanisms

Immune thrombocytopenia (ITP) is an autoimmune disease mediated by anti-platelet autoantibodies. There is growing evidence that the eradication of Helicobacter pylori (H. pylori) effectively increases platelet count in a considerable proportion of ITP patients infected with this bacterium. In the majority of ITP patients responding to H. pylori eradication therapy, the anti-platelet autoantibody response is completely resolved with no relapse for more than 7 years, indicating that the disease is cured. Therefore, adult patients with suspected ITP should be examined for H. pylori infection, and eradication therapy is recommended if the infection is present. Notably, however, the efficacy of H. pylori eradication therapy in ITP patients varies widely among countries, with a higher response rate in Japan compared with the United States and European countries other than Italy. The pathogenesis of H. pylori-associated ITP is still uncertain, although the mechanisms are known to involve multiple factors. H. pylori may modulate the Fcγ-receptor balance of monocytes/macrophages in favor of activating Fcγ receptors, and H. pylori components may mimic the molecular makeup of platelet antigens. Further studies of the pathogenic process of H. pylori-associated ITP may be useful for the development of new therapeutic strategies for ITP.

Eltrombopag in patients with chronic hepatitis C and thrombocytopenia

ABSTRACT: 

Eltrombopag is a thrombopoietic drug that acts by interacting with the TPO receptor and stimulates megakaryocytopoiesis and platelet production. Thrombocytopenia is a fairly frequent hematological abnormality in patients with chronic liver disease, and may represent an obstacle to interferon-based antiviral therapy in patients with chronic HCV infection who are otherwise good candidates for treatment. In large, multicenter, randomized, placebo-controlled studies, eltrombopag consistently enabled thrombocytopenic chronic hepatitis C patients to be treated with interferon-based therapy and, as an adjunct to antiviral therapy, has shown to be able to increase the sustained virologic response rate to treatment. The safety profile of the drug, with particular attention to the risk of thromboembolic events and the potential for hepatic decompensation, should be taken into account when planning treatment. The aim of this article is to review the information currently available regarding the pharmacokinetics, clinical efficacy and side-effect profile of eltrombopag, and to assess the role of this drug into the current and future hepatitis C treatment paradigm.

Immature platelet fraction levels in a variety of bone marrow pathologies in South African HIV-positive patients with thrombocytopenia

OBJECTIVES

Thrombocytopenia is common in HIV-infected individuals and often requires a diagnostic bone marrow examination. Interpretation may, however, be limited due to the multifactorial nature of HIV-associated thrombocytopenia and the difficulty in assessing megakaryocyte function morphologically. The immature platelet fraction (IPF) is a parameter which reportedly reflects megakaryocyte activity, with an IPF >7.7% suggesting increased platelet production. The aim of this study was to correlate the IPF with the bone marrow findings as well as other clinical variables of interest in South African patients with HIV-associated thrombocytopenia.

METHODS

Seventy-eight HIV-positive patients with thrombocytopenia were enrolled from the Charlotte Maxeke Johannesburg Academic Hospital. The IPF levels were measured using a Sysmex XE-5000 haematology analyzer and were correlated with bone marrow and other findings.

RESULTS

The median IPF was 7.6%, ranging from 1.3 to 44%. It was raised in 78% of patients with immune thrombocytopenia (ITP) (median = 16.3%) and low in 79% of patients with hypocellular marrow (median = 6.5%). Surprisingly, it was highly variable among patients with malignant marrow infiltration and mycobacterial infection of the bone marrow (BMTB) (median = 8.4 and 7.1%, respectively). Multivariate linear regression analysis confirmed a significant independent inverse relationship between the IPF and hypocellular marrow (P < 0.0001), a marginally significant positive association with ITP (P = 0.059), and the absence of any relationship with malignant infiltration or BMTB. The IPF had a significant inverse association with the platelet count (P = 0.0006), but was unrelated to the CD4 count and exposure to anti-retroviral therapy. Unexpectedly, it showed a significant positive association with the HIV viral load (P = 0.005). We speculate this to reflect increased megakaryocyte activity in compensation for accelerated platelet clearance due to HIV-driven platelet activation.

CONCLUSION

This study investigates the role of the IPF in HIV-associated thrombocytopenia, and emphasizes the limitations of morphological analysis in determining megakaryocyte function.

Baseline thrombocytopenia complicated by recurrent episodes of transient severe thrombocytopenia following infections in an adult woman with a non involuting congenital hemangioma - a case report

Background

Congenital hemangiomas are benign abnormal proliferation of blood vessels. Noninvoluting congenital hemangiomas are a rare variant which persist, and may become bigger. Hemangiomas are known to be associated with thrombocytopenia, microangiopathic hemolytic anemia and Kasabach-Merritt phenomenon. Kasabach-Merritt phenomenon is characterized by consumptive coagulopathy with microangiopathic haemolyic anemia and thrombocytopenia. Platelet sequestration in the hemangioma or increased destruction which may either be immune or non immune are also further contributors to thrombocytopenia.

Case presentation

A 45 year old female with a non involuting hemangioma and baseline thrombocytopenia was observed to develop repeated episodes of transient severe thrombocytopenia associated with a variety of infectious conditions. Laboratory investigations suggested a peripheral mechanism. Platelet counts always returned to baseline levels on resolution of the precipitating infection.

Conclusion

The authors report this phenomenon as the first reported case of baseline thrombocytopenia complicated by recurrent episodes of transient severe thrombocytopenia following infections associated with a non involuting congenital hemangioma. The observations made in this patient were unique and hitherto unreported in medical literature. Both peripheral sequestration and destructive consumption were considered likely. Consumptive mechanisms were likely to encompass either or both immune and non immune causes. Further studies are needed to establish the precise pathogenesis.

Immune thrombocytopenic purpura due to mixed viral infections

An 11-year-old boy presented with epistaxis, petechial hemorrhages, easy bruising, and purpuric rash. He was diagnosed to have immune thrombocytopenic purpura and evidence of concomitant parvovirus B19 and dengue viral infection.

Advances in megakaryocytopoiesis and thrombopoiesis: from bench to bedside

Megakaryocytopoiesis involves the commitment of haematopoietic stem cells, proliferation and terminal differentiation of megakaryocytic progenitors (MK-p) and maturation of megakaryocytes (MKs) to produce functional platelets. This complex process occurs in specialized niches in the bone marrow where MKs align adjacent to vascular endothelial cells, form proplatelet projections and release platelets into the circulation. Thrombopoietin (THPO, TPO) is the primary growth factor for the MK lineage and necessary at all stages of development. THPO is constitutively produced in the liver, and binds to MPL (c-Mpl) receptor on platelets and MKs. This activates a cascade of signalling molecules, which induce transcription factors to drive MK development and thrombopoiesis. Decreased turnover rate and platelet number result in increased levels of free THPO, which induces a concentration-dependent compensatory response of marrow-MKs to enhance platelet production. Newly developed thrombopoietic agents operating via MPL receptor facilitate platelet production in thrombocytopenic states, primarily immune thrombocytopenia. Other drugs are available for attenuating malignant thrombocytosis. Herein, we review the regulation of megakaryocytopoiesis and platelet production in normal and disease states, and the innovative drugs and therapeutic modalities to stimulate or decrease thrombopoiesis.

Gammaherpesvirus latency induces antibody-associated thrombocytopenia in mice

Human herpesviruses establish lifelong latency. Viral recrudescence can lead to the development of cancers, immunoproliferative disorders, transplantation complications, and thrombocytopenia. Although platelet-specific autoantibodies have been reported in patients infected with the Epstein-Barr virus (EBV), the mechanisms by which thrombocytopenia is induced remain unclear, as do the relative contributions of lytic viral replication and latent viral gene expression. The human gammaherpesviruses are tightly restricted in their ability to infect other mammals, so they are difficult to study in live animal models. Here we show that infection of mice with murine gammaherpesvirus-68 (γHV68), a rodent-specific pathogen closely related to EBV, induces the production of platelet-binding antibodies and causes thrombocytopenia. Infection of antibody-deficient mice does not lead to thrombocytopenia, indicating the platelet decrease is mediated by antibody. Additionally, infection with a latency-null recombinant γHV68 does not induce thrombocytopenia, suggesting factors associated with viral latency drive the infection-induced antibody-mediated thrombocytopenia. These studies describe an important animal model of gammaherpesvirus-induced autoimmune thrombocytopenia and demonstrate that this pathology is mediated by antibody and dependent on viral latency. This model will allow studies of the underlying mechanisms of disease progression and the testing of therapeutic strategies for the alleviation of virus-induced thrombocytopenia.

Pathogenesis in immune thrombocytopenia: new insights

Idiopathic (immune) thrombocytopenic purpura (ITP) is a common autoimmune disorder resulting in isolated thrombocytopenia. ITP can present either alone (primary) or in the setting of other conditions (secondary) such as infections or altered immune states. ITP is associated with a loss of tolerance to platelet antigens and a phenotype of accelerated platelet destruction and impaired platelet production. Although the etiology of ITP remains unknown, complex dysregulation of the immune system is observed in ITP patients. Antiplatelet antibodies mediate accelerated clearance from the circulation in large part via the reticuloendothelial (monocytic phagocytic) system. In addition, cellular immunity is perturbed and T-cell and cytokine profiles are significantly shifted toward a type 1 and Th17 proinflammatory immune response. Further clues into immune dysregulation in ITP may be gleaned from studies of secondary ITP. Some infections can induce antiplatelet Abs by molecular mimicry, and there may be common elements involved in breaking tolerance with other autoimmune disorders. There is also evidence for a genetic predisposition to both ITP and responsiveness to therapy, which may in part lie within immune-related genes. Lastly, treatment with immunomodulatory agents remains the mainstay of ITP therapies.

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.

Why does my patient have thrombocytopenia?

Thrombocytopenia, usually defined as a platelet count of less than 150,000/μL, is a common reason for a hematology consult in both the inpatient and outpatient setting. In most patients, the cause of the thrombocytopenia can be identified and treated. This article reviews the clinical approach to the patient with thrombocytopenia, the mechanisms that underlie it, and the laboratory tests available to investigate it. A practical approach to the investigation and management of thrombocytopenia in the clinical settings commonly encountered by the hematology consultant is then described.

Role of Helicobacter pylori infection in autoimmune diseases

PURPOSE OF REVIEW

The etiology of most autoimmune diseases remains elusive. Prevailing evidence suggests an environmental trigger in a genetically susceptible individual. Helicobacter pylori (H. pylori) have managed to survive in a hostile environment in their host for long period and have evaded eradication by the immune system. Its chronic interaction with the immune system and the ubiquitous presence worldwide makes H. pylori an ideal candidate to study as a trigger of autoimmune phenomena. In this review, we would present data regarding the interplay between H. pylori and various components of the immune system and its association with various autoimmune diseases.

RECENT FINDINGS

Strong associations of H. pylori with some autoimmune diseases such as immune thrombocytopenia have been found; but most other autoimmune disease studies have revealed conflicting data. The chronic survival of H. pylori in humans is possible because of an overall downregulation of the body's immune response. In addition to this overall effect on the immune system, there are clinical and epidemiological data suggestive of H. pylori infection having a protective role in some autoimmune diseases.

SUMMARY

Based on our review H. pylori status should be checked and treated only in certain autoimmune diseases such as ITP. For the majority of the autoimmune diseases, the role of H. pylori remains controversial signifying need for further research.

Clinical Features, Treatment, and Outcome of HIV-Associated Immune Thrombocytopenia in the HAART Era

The characteristics of HIV-associated ITP were documented prior to the HAART era, and the optimal treatment beyond HAART is unknown. We performed a review of patients with HIV-associated ITP and at least one platelet count <20 × 10⁹/L since January 1996. Of 5290 patients in the BC Centre for Excellence in HIV/AIDS database, 31 (0.6%) had an ITP diagnosis and platelet count <20 × 10⁹/L. Initial ITP treatment included IVIG, n = 12; steroids, n = 10; anti-RhD, n = 8; HAART, n = 3. Sixteen patients achieved response and nine patients achieved complete response according to the International Working Group criteria. Median time to response was 14 days. Platelet response was not significantly associated with treatment received, but complete response was lower in patients with a history of injection drug use. Complications of ITP treatment occurred in two patients and there were four unrelated deaths. At a median followup of 48 months, 22 patients (71%) required secondary ITP treatment. This is to our knowledge the largest series of severe HIV-associated ITP reported in the HAART era. Although most patients achieved a safe platelet count with primary ITP treatment, nearly all required retreatment for ITP recurrence. New approaches to the treatment of severe ITP in this population are needed.

The inhibition effect of anti-GPIIIa49-66 antibody on megakaryocyte differentiation

We previously reported that patients with early-onset HIV-1 ITP developed a unique anti-platelet integrin GPIIIa antibody against the GPIIIa49-66 epitope. Anti-GPIIIa49-66 antibody-induced platelet fragmentation requires sequential activation of the platelet 12-lipoxygenase (12-LO) and NADPH oxidase to release reactive oxygen species (ROS). 12-LO is upstream of the NADPH oxidase pathway and 12(S)-HETE, the product of 12-LO, induces the same oxidative platelet fragmentation as anti-GPIIIa49-66. Since the megakaryocyte (MK) is the progenitor cell for platelets, we have investigated the effect of anti-GPIIIa49-66 on MK differentiation and, in particular, the potential role of anti-GPIIIa49-66 induced ROS in this process. We first show that polyclonal anti-GPIIIa49-66 antibody isolated from HIV-1 ITP patients inhibits MK proliferation 2.5-fold in in vitro culture of human cord blood CD34+ cells driven by thrombopoietin (TPO). We also observe a three-fold decrease in the number of MK colony-forming units in the presence of a human monoclonal anti-GPIIIa49-66 antibody. However, we could not detect ROS release in DCFH-loaded mouse megakaryoblastic cells L8057 treated with anti-GPIIIa49-66 antibody. In addition, 12(S)-HETE does not inhibit the in vitro differentiation of L8057 cells induced by TPO. In fact, we found a dose dependent increase in the percentage of CD41 positive cells (from 17.1% to 48.7%) in in vitro culture of L8057 cells treated with various concentrations of H2O2 (from 5 to 20 μM). We therefore conclude that the anti-GPIIIa49-66 antibody inhibits MK differentiation through β3 integrin signalling independent of ROS release.

Horizontal gene transfers with or without cell fusions in all categories of the living matter

This article reviews the history of widespread exchanges of genetic segments initiated over 3 billion years ago, to be part of their life style, by sphero-protoplastic cells, the ancestors of archaea, prokaryota, and eukaryota. These primordial cells shared a hostile anaerobic and overheated environment and competed for survival. "Coexist with, or subdue and conquer, expropriate its most useful possessions, or symbiose with it, your competitor" remain cellular life's basic rules. This author emphasizes the role of viruses, both in mediating cell fusions, such as the formation of the first eukaryotic cell(s) from a united crenarchaeon and prokaryota, and the transfer of host cell genes integrated into viral (phages) genomes. After rising above the Darwinian threshold, rigid rules of speciation and vertical inheritance in the three domains of life were established, but horizontal gene transfers with or without cell fusions were never abolished. The author proves with extensive, yet highly selective documentation, that not only unicellular microorganisms, but the most complex multicellular entities of the highest ranks resort to, and practice, cell fusions, and donate and accept horizontally (laterally) transferred genes. Cell fusions and horizontally exchanged genetic materials remain the fundamental attributes and inherent characteristics of the living matter, whether occurring accidentally or sought after intentionally. These events occur to cells stagnating for some 3 milliard years at a lower yet amazingly sophisticated level of evolution, and to cells achieving the highest degree of differentiation, and thus functioning in dependence on the support of a most advanced multicellular host, like those of the human brain. No living cell is completely exempt from gene drains or gene insertions.

Fournier's gangrene in a patient receiving treatment for idiopathic thrombocytopenic purpura

We report the case of a 68-year-old man who was diagnosed with Fournier's gangrene (FG), which developed during immunosuppresive treatment for idiopathic thrombocytopenic purpura (ITP). The patient was administered steroids for ITP but on the 36th day, he developed FG and septic shock. We initiated antibiotic treatment and drained a periproctal abscess immediately. On day 53, extensive drainage to progressive FG and a splenectomy was performed, following which both FG and thrombocytopenia improved. This is the first case of FG has developing in a ITP patient. It appears that high-dose immunoglobulin therapy and splenectomy should be considered earlier especially for a patient complicated with FG.

Prevalence of thrombocytopenia among patients with chronic hepatitis C: a systematic review

Thrombocytopenia (TCP) is a haematological condition known to occur in chronically infected hepatitis C (HCV) patients and may interfere with diagnostic procedures, such as liver biopsy, because of risk of bleeding. It may also exclude patients from effective antiviral treatment. We conducted a systematic literature review of articles and conference abstracts, to assess the prevalence of TCP among those with HCV and to describe demographics, liver disease stage and treatment characteristics of these patients. Studies of individuals with confirmed chronic HCV infection were included in the review if the study had a clear definition of thrombocytopenia and a sample size of at least 50 subjects. The final selection included 27 studies (21 articles and six abstracts). The definitions of thrombocytopenia varied between studies and were based either on platelet counts, with threshold levels ranging between ≤ 100 × 10(9) and ≤ 180 × 10(9) /L, or on criteria set in haematological guidelines. The prevalence of TCP ranged from 0.16% to 45.4% and more than half of the studies reported a TCP prevalence of 24% or more. Because of the different TCP definitions, heterogeneity in study design and insufficient data on study characteristics such as age, gender, HCV treatment rates and disease severity an overall summary estimate of TCP prevalence among patients with HCV was not feasible. However, the relatively large prevalence in the majority of the studies suggests that there may be a substantial number of HCV patients at risk of bleeding complications and reduced likelihood of successful HCV antiviral treatment.

Candida albicans-induced chronic thrombocytopenic purpura

We present 2 patients with chronic immune thrombocytopenic purpura (ITP) secondary to Candida albicans infection. Neither patient responded to standard ITP therapy including splenectomy. Appropriate antifungal treatment of the C. albicans infection was followed by sustained improvement in platelet count in both patients. To our knowledge, this is the first report of ITP in association with C. albicans infection.

Complicated lower extremity wound caused by immune thrombocytopenic purpura leading to hypercoagulable state: a team approach for limb salvage

This article describes a complicated lower extremity wound due to hypercoagulable state caused by immune thrombocytopenic purpura. A team approach was important to limb salvage. A literature review is included.