Other immune thrombocytopenias

Introduction of direct-acting antiviral agents alters frequencies of anti-GPIIb/IIIa antibody-producing B cells in chronic hepatitis C patients with thrombocytopenia

The pathogenesis of thrombocytopenia in chronic hepatitis C (CHC) conceivably involves autoimmunity; however, the dynamics of autoantibodies and other autoimmune mechanisms remain unclear. In this study, we examined the changes in the frequency of anti-glycoprotein (GP) IIb/IIIa antibody-producing B cells and the levels of plasma B-cell-activating factor (BAFF), a proliferation-inducing ligand (APRIL), and interleukin (IL)-21 following treatment of CHC with direct-acting antiviral agents (DAA). We recruited 28 patients with CHC who underwent treatment with DAA for 8-12 weeks and subsequently tested negative for serum hepatitis C virus RNA. Thirty healthy controls were recruited for comparison. Platelet counts increased significantly (p = .016), and the frequency of anti-GPIIb/IIIa antibody-producing B cells decreased significantly (p = .002) in CHC patients with thrombocytopenia at the end of treatment (EOT) than before DAA treatment (baseline). However, these changes were not observed in CHC patients without thrombocytopenia. Plasma BAFF levels in CHC patients with thrombocytopenia significantly decreased from baseline to EOT (p = .002). Anti-GPIIb/IIIa antibody-producing B cells were positively correlated with plasma BAFF levels in these patients (r = 0.669, p = .039). These results suggest that DAA treatment suppresses the autoimmune response against platelets and improves thrombocytopenia.

Maternal Coagulation Disorders and Postpartum Hemorrhage

Coagulation disorders are rare causes of postpartum hemorrhage. Disturbances in coagulation should be suspected in patients with a family history of coagulopathy, those with a personal history of heavy menstrual bleeding, and those with persistent bleeding despite correction of other causes. The coagulopathic conditions discussed include disseminated intravascular coagulation, platelet disorders, and disturbances of coagulation factors. These should not be overlooked in the evaluation of obstetric hemorrhage, as diagnosis and appropriate treatment may prevent severe maternal morbidity and mortality.

Etiological Profiles of Patients With Thrombocytopenia in Central India: A Tertiary Centre Study

Introduction Platelet-related disease may result from an abnormal platelet count, namely thrombocytopenia or thrombocythemia, or altered platelet function, and thus is associated with bleeding or with thrombotic manifestation. Thrombocytopenia is defined as a subnormal number of platelets i.e. less than 1,50,000/µL in the peripheral blood. It can lead to inadequate clot formation and increased risk of bleeding and is a common indication for bone marrow aspiration and biopsy. Methodology The study was a hospital-based prospective observational study from January 2019 to June 2020. All cases of thrombocytopenia which were diagnosed first on haematology analyser (platelet counts <150,000/µL) and confirmed subsequently by peripheral smear with/without bleeding manifestations due to thrombocytopenia were taken up for the study. The aims and objectives of this study were to find out the epidemiological spectrum and prevalence of thrombocytopenia according to age and sex along with the correlation of haematological and bone marrow findings of such patients. Result This study comprised 100 cases of thrombocytopenia, with acute leukaemia accounting for the majority (28/100), followed by dimorphic anaemia (15/100), megaloblastic anaemia (11/100), hypocellular marrow, infection, and other conditions. All cases (100%) displayed the clinical symptom of widespread weakness and pallor, which was followed by fatiguability (72%) and dyspnoea (48%). Many thrombocytopenic individuals also had lymphadenopathy and hepatomegaly, the last two least common appearances. Lymphadenopathy and hepatomegaly which were the last two least common presentations were present in a significant number of thrombocytopenic patients. Conclusion The study of bone marrow is helpful in the diagnosis of thrombocytopenia cases. Bone marrow examination is a simple, safe outpatient procedure and yields an impressive amount of diagnostically valuable data in a wide variety of disorders of thrombocytopenia. An evaluation of the patient's bone marrow unquestionably aids in the early diagnosis and treatment of their ailment.

Pathophysiology of Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) and Vaccine-Induced Thrombocytopenic Thrombosis (VITT) and Their Diagnostic Approach in Emergency

SARS-CoV-2 induced a pandemic that is reported to have started in Asia and was then extended to other countries in the world. Main clinical aspects of this viral infection have been lung injuries with severe pneumonia requiring prolonged hospitalization and associated morbidities such as venous thromboembolism and/or superinfection by bacteria, fungus or other pests. Immediately there was a need to develop a sustainable therapeutic strategy, such as vaccination. Vaccines against Covid-19, in fact, exert a protective action for common people and reduce viral diffusion. Yet, vaccination of a large number of people raises the question of a well-known complication of several types of vaccines; this complication is immune thrombocytopenia, which is sometimes associated with thrombosis as well. In this short review, we summarized mechanisms involved in the pathogenesis of vaccine-induced prothrombotic immune thrombocytopenia and vaccine-induced thrombocytopenic thrombosis.

Understanding Immune Thrombocytopenia: Looking Out of the Box

The pathogenesis of immune thrombocytopenia (ITP) is increasingly being elucidated, and its etiology is becoming more frequently identified, leading to a diagnostic shift from primary to secondary ITP. The overlap between autoimmunity, immunodeficiency, and cancer is evident, implying more interdisciplinarity in daily care. This mini-review is based on an expert meeting on ITP organized by the Intercontinental Cooperative ITP Study Group and presents the challenges of hematologists in understanding and investigating "out of the box" concepts associated with ITP.

Misdiagnosed thrombocytopenia in children and adolescents: analysis of the Pediatric and Adult Registry on Chronic ITP

Primary immune thrombocytopenia (ITP) in children is a diagnosis of exclusion, but cases of secondary ITP and nonimmune thrombocytopenia (non-IT) are generally difficult to recognize in a timely fashion. We describe a pediatric population with a revised diagnosis of secondary ITP or non-IT within 24 months of follow-up. Data were extracted from the Pediatric and Adult Registry on Chronic ITP, an international multicenter registry collecting data prospectively in patients with newly diagnosed primary ITP. Between 2004 and 2019, a total of 3974 children aged 3 months to 16 years were included. Secondary ITP and non-IT were reported in 113 patients (63 female subjects). Infectious (n = 53) and autoimmune (n = 42) diseases were identified as the main causes, with median ages at diagnosis of 3.2 years (interquartile range: 1.2; 6.7 years) and 12.4 years (interquartile range: 7.6; 13.7 years), respectively. Other causes included malignancies, aplastic anemia, immunodeficiency, and drug use. Patients with malignancy and aplastic anemia had significantly higher initial platelet counts (37 and 52 × 109/L) than did those with infection or autoimmune diseases (12 and 13 × 109/L). Characteristics of patients with secondary ITP due to infection were similar to those of children with primary ITP at first presentation, indicating similar mechanisms. Significant differences were found for age, sex, comorbidities, initial bleeding, sustained need for treatment, and disease persistence for the remaining noninfectious group compared with primary ITP. Based on our findings, we propose a diagnostic algorithm that may serve as a basis for further discussion and prospective trials.

Clinical association between thyroid disease and immune thrombocytopenia

Immune thrombocytopenia (ITP) can coexist with autoimmune thyroid disease. However, the detailed clinical features remain unknown. We retrospectively reviewed 248 patients with newly diagnosed ITP in our institute for whom we had thyroid function data at diagnosis between 2000 and 2019. Of the 248 patients with ITP, 74 patients also had thyroid disease, including 36 with overt thyroid disease (13 Graves' disease and 23 Hashimoto's thyroiditis) and 38 with subclinical thyroid disease (3 hyperthyroidism and 35 hypothyroidism). ITP and thyroid disease were concurrently diagnosed in 54 patients. Female sex and positivity for antinuclear antibodies (ANA) were significantly associated with thyroid diseases. Platelet-associated immunoglobulin G (PAIgG) levels in patients with Graves' disease were higher than those in patients with Hashimoto's thyroiditis. Platelet counts were similar among euthyroid patients and patients with thyroid disease. Thrombopoietin-receptor agonist was administered more frequently in patients with thyroid disease. The cumulative incidences of thrombosis and bleeding and overall survival did not differ between patients with and without thyroid disease. Treatment for thyroid disease in 22 patients improved thrombocytopenia in 21 patients, especially in 4 patients who were not treated for ITP. This study demonstrated that thyroid diseases were commonly found in patients with ITP. Treatment of the underlying thyroid disease may improve thrombocytopenia.

Crosstalk Between Platelets and Microbial Pathogens

Platelets, small anucleate cells circulating in the blood, are critical mediators in haemostasis and thrombosis. Interestingly, recent studies demonstrated that platelets contain both pro-inflammatory and anti-inflammatory molecules, equipping platelets with immunoregulatory function in both innate and adaptive immunity. In the context of infectious diseases, platelets are involved in early detection of invading microorganisms and are actively recruited to sites of infection. Platelets exert their effects on microbial pathogens either by direct binding to eliminate or restrict dissemination, or by shaping the subsequent host immune response. Reciprocally, many invading microbial pathogens can directly or indirectly target host platelets, altering platelet count or/and function. In addition, microbial pathogens can impact the host auto- and alloimmune responses to platelet antigens in several immune-mediated diseases, such as immune thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. In this review, we discuss the mechanisms that contribute to the bidirectional interactions between platelets and various microbial pathogens, and how these interactions hold relevant implications in the pathogenesis of many infectious diseases. The knowledge obtained from "well-studied" microbes may also help us understand the pathogenesis of emerging microbes, such as SARS-CoV-2 coronavirus.

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.

Red blood cell distribution width and platelet counts are independent prognostic factors and improve the predictive ability of IPI score in diffuse large B-cell lymphoma patients

Background

Elevated red blood cell distribution width (RDW) and decreased platelet count (PLT) can be clinically relevant to the prognosis in cancer patients. However, their prognostic values in patients with diffuse large B-cell lymphoma (DLBCL) need to be further explored.

Methods

Healthy donors (n = 130) and patients with DLBCL (n = 349) were included and evaluated retrospectively in this study. The prognostic influence of clinical and pathological factors including RDW and PLT on overall survival (OS) and progression-free survival (PFS) were studied by Kaplan-Meier curves. To evaluate the independent prognostic relevance of RDW and PLT, univariate and multivariate Cox proportional hazards regression models were applied. The adjusted IPI model was established based on the results of multivariate analysis, and verified by Harrell’s C statistical analysis.

Results

Kaplan-Meier curves indicated that an elevated RDW value and thrombocytopenia are poor factors for OS (P < 0.001, P = 0.006) and PFS (P = 0.003, P < 0.001) in DLBCL patients. Multivariate analysis confirmed that elevated RDW value (HR = 2.026, 95%CI = 1.263–3.250, P = 0.003) and decreased PLT count (HR =1.749, 95%CI = 1.010–3.028, P = 0.046) were both independent prognostic factors. The c-index of IPI and NCCN-IPI were increased when RDW level and PLT were supplemented in our cohort.

Conclusions

Our study shows that elevated RDW level and decreased PLT are independent poor prognostic factors in newly diagnosed DLBCL patients. Adding RDW and PLT to the IPI score may improve its predictive ability, and the adjusted IPI may be more powerful in predicting the survival of DLBCL patients in the rituximab era.

Clinical features and prognostic factors of primary bone marrow lymphoma

Background

Primary bone marrow lymphoma (PBML) is a very uncommon neoplasm originally arising in the bone marrow system, and the most common pathological type is diffuse large B-cell lymphoma.

Patients and methods

To describe the clinical characteristics of PBML and evaluate the risk factors related to prognosis, we recruited and studied 66 patients from our center and the current published literature. Various symptoms are present at the onset of PBML, the most important of which is cytopenia, followed by fever. Forty-seven of these patients were included in our analysis.

Results

Univariate analysis suggested that B symptoms (P=0.024), a low serum platelet level (<75×10⁹/L; P=0.032), an elevated serum LDH level (P=0.039), and not achieving a complete response (CR) following initial therapy (P=0.007) are associated with worse outcomes. Multivariate analysis showed that only a low serum platelet level (<75×10⁹/L), B symptoms, and not achieving a CR following initial therapy are independent factors for prognosis. In addition, intensive regimens appear to be beneficial for prognosis.

Conclusion

PBML is a lymphoma with special clinical features, and its recognition is important for establishing a definitive prognosis model and searching for appropriate therapy.

Evaluation of coagulation disorders by thromboelastography in children with systemic lupus erythematosus

Background

The coagulation status of patients with systemic lupus erythematosus (SLE) is quite complicated, and there are currently no simple efficient methods for its evaluation. We explored the feasibility of thromboelastography (TEG) for this purpose.

Methods

Paediatric SLE patients were divided into different groups based on Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores. TEG parameters were compared between patients and healthy controls (HCs) and in patients by level of disease activity. Six patients treated with pulse methylprednisolone were also analysed before and after treatment.

Results

Thirty-nine children with SLE were enrolled, one of whom had bleeding and three of whom had thrombosis. The four TEG tracings of these four children were different. The TEG parameters of the patients (except the four children mentioned above) showed hypercoagulability, shortened R and K times, increased α-angle and maximum amplitude (MA), decreased LY30 and increased clot index (CI) compared with the parameters of the HCs ( P < 0.05). With respect to disease activity, patients with higher SLEDAI scores showed more obvious hypercoagulability with shortened R and K times and increased α-angle and CI ( P < 0.05). Furthermore, there was a negative correlation between both the R time and K time and SLEDAI scores ( r = –0.435, P < 0.01 and r  =  –0.572, P  < 0.001, respectively) and a positive correlation between both α-angle and CI and SLEDAI scores ( r = 0.581, P  < 0.001 and r  =  0.544, P  < 0.01, respectively). No significant difference in coagulation status was found between pre- and post-pulse therapy.

Conclusions

Compared with the HCs, paediatric SLE patients showed hypercoagulability caused by increased coagulation and decreased fibrinolysis. These coagulation changes were associated with disease activity. TEG could be a potential tool for evaluating the coagulation status of children with SLE.

How do we diagnose immune thrombocytopenia in 2018?

In this report, we will review the various clinical and laboratory approaches to diagnosing immune thrombocytopenia (ITP), with a focus on its laboratory diagnosis. We will also summarize the results from a number of laboratories that have applied techniques to detect anti-platelet autoantibodies as diagnostic tests for ITP. Although there is considerable variability in methods among laboratories, there is general agreement that platelet autoantibody testing has a high specificity but low sensitivity. This suggests several possibilities: (1) the ideal test for ITP has yet to be developed, (2) current test methods need to be improved, or (3) ITP is the clinical expression of a variety of thrombocytopenic disorders with different underlying mechanisms. Even the clinical diagnosis of ITP is complex, and experienced clinicians do not always agree on whether a particular patient has ITP. Improvements in the diagnostic approach to ITP are necessary to improve the management of this disorder.

Hepatitis B infection is associated with an increased incidence of thrombocytopenia in healthy adults without cirrhosis

The association between HBV infection and incident thrombocytopenia among subjects without cirrhosis or splenomegaly is unknown. Therefore, we sought to elucidate the association between HBV infection and the development of thrombocytopenia in a large cohort of apparently healthy men and women. A cohort study was performed in 122 200 participants without liver cirrhosis or splenomegaly who underwent comprehensive health examinations and were followed until December 2014. HBV infection was defined by the presence of hepatitis B surface antigen (HBsAg) at baseline. Thrombocytopenia was defined as a platelet count <150 000/μL. Cox proportional hazard models were used to estimate adjusted hazard ratios with 95% confidence intervals (CIs) for incident thrombocytopenia. HBsAg was positive in 4857 of 122 200 subjects (4.0%) at baseline. During 883 983 person-years of follow-up, 2037 incident cases of thrombocytopenia were identified (incident rate 2.3 per 1000 person-years). HBsAg-positive subjects had a higher incidence of thrombocytopenia than did healthy controls (11.2 vs 1.9 per 1000 person-years, respectively). The multivariate-adjusted hazard ratio (95% CI) for incident thrombocytopenia comparing HBsAg-positive to HBsAg-negative subjects was 5.71 (5.10-6.38). Strong associations between HBsAg positivity and thrombocytopenia were consistently observed across prespecified subgroups. In this large cohort study of an apparently healthy population, HBsAg positivity was strongly and independently associated with incident thrombocytopenia, indicating that mechanisms of thrombocytopenia other than portal hypertension may exist in healthy HBV carriers.

Treatment of patients with immune thrombocytopenia admitted to the emergency room

Immune thrombocytopenia (ITP) is the most frequent cause of acquired thrombocytopenia. In adult ITP patients, corticosteroids and intravenous immunoglobulin (IVIg) are used as first-line treatment. The aim of the present study was to investigate retrospectively the demographic and etiologic characteristics of patients with ITP admitted to the emergency room at our hospital. Seventy-five adult patients with ITP were included, and demographic data, bleeding characteristics, etiologic features and responses to treatments were evaluated retrospectively. Fifty-six patients (75 %) were female, and the median age was 43 years. Eighteen patients had a history of ITP, whereas in 57, thrombocytopenia was identified for the first time. During admission, the median platelet count was 5 × 10(9)/L. Cutaneous and/or mucosal bleeding was the most common clinical feature. High-dose dexamethasone was administered in 60 episodes, whereas IVIg and conventional-dose methylprednisolone were used in nine and six episodes, respectively. The overall response rate of the entire cohort following first-line treatments was 67 %, and complete remission was achieved in 31 patients, 19 patients achieved partial remission, and 25 patients were non-responders. In cases with life-threatening bleeding, concomitant infection, post-traumatic bleeding and need for emergency surgery, IVIg can be used as the first line of treatment option in addition to platelet transfusions.

Immune thrombocytopenia and autoimmune thyroid disease: a controversial overlap

Immune thrombocytopenia (ITP) is an entity characterized by a platelet count of less than 100 × 10⁹/L in the absence of other causes of thrombocytopenia, such as viral infections, rheumatic diseases, or drugs. Grave’s disease is also an autoimmune condition in which thrombocytopenia is often observed. Moreover, in the literature, many reports show a marked interference of the thyroid dysfunction (mainly hyperthyroidism) in the control of thrombocytopenia. Although this issue still remains debatable, the authors report the case of a young woman with a previous diagnosis of ITP with a brilliant initial response to corticotherapy. Some years after this diagnosis, the patient presented thyrotoxicosis due to Grave’s disease and the thrombocytopenia relapsed, but this time there was no response to the glucocorticoids. Only after the radioiodine I-131 thyroid ablation the control of thrombocytopenia was achieved. The authors call attention to this overlap and for testing thyroid function in every patient with an unexpected negative response to corticotherapy.

Platelets and platelet alloantigens: Lessons from human patients and animal models of fetal and neonatal alloimmune thrombocytopenia

Platelets play critical roles in hemostasis and thrombosis. Emerging evidence indicates that they are versatile cells and also involved in many other physiological processes and disease states. Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a life threatening bleeding disorder caused by fetal platelet destruction by maternal alloantibodies developed during pregnancy. Gene polymorphisms cause platelet surface protein incompatibilities between mother and fetus, and ultimately lead to maternal alloimmunization. FNAIT is the most common cause of intracranial hemorrhage in full-term infants and can also lead to intrauterine growth retardation and miscarriage. Proper diagnosis, prevention and treatment of FNAIT is challenging due to insufficient knowledge of the disease and a lack of routine screening as well as its frequent occurrence in first pregnancies. Given the ethical difficulties in performing basic research on human fetuses and neonates, animal models are essential to improve our understanding of the pathogenesis and treatment of FNAIT. The aim of this review is to provide an overview on platelets, hemostasis and thrombocytopenia with a focus on the advancements made in FNAIT by utilizing animal models.

Prevalence of HIV-related thrombocytopenia among clients at Mbarara Regional Referral Hospital, Mbarara, southwestern Uganda

Aims/objectives

We aimed to determine the prevalence and correlates of thrombocytopenia among people living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) and to assess occurrence of antiplatelet antibodies, among thrombocytopenic HIV clients at Mbarara Regional Referral Hospital, southwestern Uganda.

Materials and methods

This was a retrospective review of hematologic results at enrollment to HIV care from 2005 to 2013. The prevalence and correlates of thrombocytopenia were estimated based on the Immune Suppressed Syndrome (ISS) Clinic electronic database. A cross-sectional study determined the occurrence of antiplatelet antibodies, using the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) technique.

Results

We reviewed 15,030 client records. The median age was 35.0 (range 18–78; interquartile range [IQR] 28–42) years, and there were 63.2% (n=9,500) females. The overall prevalence of thrombocytopenia was 17.4% (95% confidence interval [CI]: 16.8%–18.0%). The prevalence of thrombocytopenia was 17.8% (95% CI: 17.1%–18.4%) among antiretroviral therapy (ART)-naïve clients (n=2,675) and was 13.0% (95% CI: 0.3%–21.9%) for clients who were on ART (n=6). The study found a significant association between thrombocytopenia and other cytopenias, CD4 counts, ART, and deteriorating HIV stage (P<0.05). Two of the 40 participants (5.0%) had antiplatelet antibodies.

Conclusion

This study has showed a high prevalence of HIV-related thrombocytopenia. Antiplatelet antibodies were found in 5.0% of HIV-infected thrombocytopenic participants. Our study shows a significant association of thrombocytopenia burden in a high-HIV study population (Southwest Uganda); therefore, there is need to monitor platelet counts and initiate platelet transfusion in our blood banking practices, to avert possible risks of bleeding.

Helicobacter pylori and autoimmune disease: Cause or bystander

Helicobacter pylori (H. pylori) is the main cause of chronic gastritis and a major risk factor for gastric cancer. This pathogen has also been considered a potential trigger of gastric autoimmunity, and in particular of autoimmune gastritis. However, a considerable number of reports have attempted to link H. pylori infection with the development of extra-gastrointestinal autoimmune disorders, affecting organs not immediately relevant to the stomach. This review discusses the current evidence in support or against the role of H. pylori as a potential trigger of autoimmune rheumatic and skin diseases, as well as organ specific autoimmune diseases. We discuss epidemiological, serological, immunological and experimental evidence associating this pathogen with autoimmune diseases. Although over one hundred autoimmune diseases have been investigated in relation to H. pylori, we discuss a select number of papers with a larger literature base, and include Sjögrens syndrome, rheumatoid arthritis, systemic lupus erythematosus, vasculitides, autoimmune skin conditions, idiopathic thrombocytopenic purpura, autoimmune thyroid disease, multiple sclerosis, neuromyelitis optica and autoimmune liver diseases. Specific mention is given to those studies reporting an association of anti-H. pylori antibodies with the presence of autoimmune disease-specific clinical parameters, as well as those failing to find such associations. We also provide helpful hints for future research.

Prevalence and clinical significance of antithyroid antibodies in children with immune thrombocytopenic purpura

BACKGROUND AND OBJECTIVE

To determine the prevalence and the clinical significance of thyroid autoantibodies and their influence on treatment response in children with idiopathic thrombocytopenic purpura (ITP).

PATIENT AND METHOD

We retrospectively analyzed the antithyroglobulin (anti-TG) and antithyroid peroxidase (anti-TPO) antibodies from the records of 151 ITP patients who were admitted to the Pediatric Hematology Department of Gaziantep University between 2009 and 2012.

RESULTS

Anti-TPO and/or anti-TG was found positive in 38 (36.8%) of 103 patients whose thyroid autoantibody levels were measured. The comparison of positivity ratios of autoantibodies between acute and chronic ITP patients showed no significant difference. However, the separate comparison of each group of ITP patients with control group showed significantly high positivity ratios of autoantibodies in ITP patients. The initial mean platelet count of anti-TPO positive patients at diagnosis was significantly less than that of the negative patients (P = .008). One month after treatment, platelet count of anti-TPO positive patients was significantly less than that of the negative patients (P = .01). Moreover, the mean platelet counts of anti-TPO positive patients were significantly less than those of the negative patients after intravenous immunoglobulin treatment (P < .001).

CONCLUSION

We demonstrated that the thyroid-autoimmune-diseases-related autoantibodies are frequently found in childhood ITP. Although no recommendation is found in international guidelines regarding screening for thyroid autoantibodies in patients with ITP, in view of the high incidence of antithyroid antibodies and their potential negative effect on treatment response, screening these patients for such antibodies would be recommended.

Platelets as immune cells in infectious diseases

Platelets have been shown to cover a broad range of functions. Besides their role in hemostasis, they have immunological functions and thus participate in the interaction between pathogens and host defense. Platelets have a broad repertoire of receptor molecules that enable them to sense invading pathogens and infection-induced inflammation. Consequently, platelets exert antimicrobial effector mechanisms, but also initiate an intense crosstalk with other arms of the innate and adaptive immunity, including neutrophils, monocytes/macrophages, dendritic cells, B cells and T cells. There is a fragile balance between beneficial antimicrobial effects and detrimental reactions that contribute to the pathogenesis, and many pathogens have developed mechanisms to influence these two outcomes. This review aims to highlight aspects of the interaction strategies between platelets and pathogenic bacteria, viruses, fungi and parasites, in addition to the subsequent networking between platelets and other immune cells, and the relevance of these processes for the pathogenesis of infections.

Etiology and significance of thrombocytopenia in critically ill patients

Thrombocytopenia is common in critically ill patients and increases morbidity and mortality. A diagnosis of heparin-induced thrombocytopenia (HIT) is frequently considered in any ICU patient who develops thrombocytopenia in the context of ongoing heparin exposure. As the usual tests to diagnose HIT are often neither specific nor sensitive enough to be confirmatory, the intensivist must largely rely on clinical judgment in treatment decisions. Patients in the ICU may also develop thrombocytopenia resulting from non-HIT immune mechanisms, nonimmune platelet consumption, and from decreased platelet production due to preexisting disorders or as a result of their critical illness and/or drug therapy.

Crosstalk between Platelets and the Immune System: Old Systems with New Discoveries

Platelets are small anucleate cells circulating in the blood. It has been recognized for more than 100 years that platelet adhesion and aggregation at the site of vascular injury are critical events in hemostasis and thrombosis; however, recent studies demonstrated that, in addition to these classic roles, platelets also have important functions in inflammation and the immune response. Platelets contain many proinflammatory molecules and cytokines (e.g., P-selectin, CD40L, IL-1β, etc.), which support leukocyte trafficking, modulate immunoglobulin class switch, and germinal center formation. Platelets express several functional Toll-like receptors (TLRs), such as TLR-2, TLR-4, and TLR-9, which may potentially link innate immunity with thrombosis. Interestingly, platelets also contain multiple anti-inflammatory molecules and cytokines (e.g., transforming growth factor-β and thrombospondin-1). Emerging evidence also suggests that platelets are involved in lymphatic vessel development by directly interacting with lymphatic endothelial cells through C-type lectin-like receptor 2. Besides the active contributions of platelets to the immune system, platelets are passively targeted in several immune-mediated diseases, such as autoimmune thrombocytopenia, infection-associated thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. These data suggest that platelets are important immune cells and may contribute to innate and adaptive immunity under both physiological and pathological conditions.

Prognostic value of platelet count in diffuse large B-cell lymphoma

BACKGROUND

Besides International Prognostic Index, many parameters have proven prognostic significance in aggressive lymphoma. However, the most appropriate system of risk stratification in diffuse large B-cell lymphoma (DLBCL) is not yet clear. In this study, we attempt to clarify the prognostic value of platelet count at the onset of lymphoma.

MATERIALS AND METHODS

Between January 2000 and December 2009, 100 patients with DLBCL receiving R-CEOP (rituximab, cyclophosphamide, epirubicin, vincristine, and prednisolone) in a single institution were enrolled. Patient characteristics and survival outcomes were retrospectively analyzed.

RESULTS

Before front-line treatment, 17 patients with thrombocytopenia (< 150 × 10(9)/L) and 83 patients without thrombocytopenia were enrolled. Thrombocytopenic patients initially presented with more B symptoms (P = .040), more bone marrow involvement (P = .001), later staging (P = .001), and higher International Prognostic Index (P < .001). Thrombocytopenia was shown to be an independently poor prognostic factor in the multivariate analysis of overall survival (hazard ratio [HR], 3.405; 95% confidence interval [CI], 1.431-8.101; P = .006) and progression-free survival (HR, 4.299; 95% CI, 1.786-10.343; P = .001).

CONCLUSION

Platelet count at diagnosis is a simple but useful indicator for predicting survival outcomes of DLBCL. Although the mechanisms of thrombocytopenia may be complex in lymphoma, further investigations are warranted to illustrate the predictive merit.

Helicobacter pylori and autoimmune diseases

Helicobacter pylori (H. pylori) is a widely prevalent microbe, with between 50 and 80% of the population infected worldwide. Clinically, infection with H. pylori is commonly associated with peptic ulcer disease, but many of those infected remain asymptomatic. H. pylori has evolved a number of means to affect the host immune response and has been implicated in many diseases mitigated by immune dysregulation, such as immune thrombocytopenic purpura (ITP), atrophic gastritis, and mucosa associated lymphoid tissue (MALT) lymphoma. Autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and Sjogren's syndrome, are the result of a dysregulated host immune system which targets otherwise healthy tissues. The exact etiology of autoimmune diseases is unclear, but it has long been suggested that exposure to certain environmental agents, such as viral and bacterial infection or chemical exposures, in genetically susceptible individuals may be the catalyst for the initiation of autoimmune processes. Because of its prevalence and ability to affect human immune function, many researchers have hypothesized that H. pylori might contribute to the development of autoimmune diseases. In this article, we review the available literature regarding the role of chronic H. pylori infection in various autoimmune disease states.

Immune thrombocytopenia in lymphoproliferative disorders

Lymphoproliferative disorders are recognized as a common cause of secondary immune thrombocytopenia (ITP). The mechanisms involved in the pathogenesis of ITP associated with lymphoproliferative disorders are heterogeneous and often linked to the presence and activity of the malignant clone. A better understanding of the responsible mechanisms leading to ITP in each disease may allow for targeted treatment decisions, avoiding unwarranted immunosuppression and bleeding complications.

Immune thrombocytopenic purpura at the diagnosis of Hodgkin disease

We describe the case of a 76-year-old male presenting a thrombocytopenia at the diagnosis of Hodgkin disease. Basing on bone marrow biopsy and evolution, we diagnosed an immune thrombocytopenia and treated with intravenous gammaglobulins. The platelet count normalized in a few days under this therapy. Immune thrombocytopenia purpura (ITP) is a rare complication of Hodgkin disease (HD). It seems to be due to the production of antibodies directed against platelet membrane proteins. The patient's and the lymphoma's characteristics are not predictive for it to happen. The evolution of HD is also not influenced by its occurrence. Various treatments (including corticoids and immunomodulating agents) have been tried with different efficiencies.

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.

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.

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 Fcγ 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.