Immune thrombocytopenic purpura

Translating mechanisms into therapeutic strategies for immune thrombocytopenia (ITP): Lessons from clinical trials

Immune thrombocytopenia (ITP) is an autoimmune disorder that causes a significant reduction in peripheral blood platelet count. Fortunately, due to an increased understanding of ITP, there have been significant improvements in the diagnosis and treatment of these patients. Over the past decade, there have been a variety of proven therapeutic options available for ITP patients, including intravenous immunoglobulins (IVIG), Rituximab, corticosteroids, and thrombopoietin receptor agonists (TPO-RAs). Although the effectiveness of current therapies in treating more than two-thirds of patients, still some patients do not respond well to conventional therapies or fail to achieve long-term remission. Recently, a significant advancement has been made in identifying various mechanisms involved in the pathogenesis of ITP, leading to the development of novel treatments targeting these pathways. It seems that new agents that target plasma cells, Bruton tyrosine kinase, FcRn, platelet desialylation, splenic tyrosine kinase, and classical complement pathways are opening new ways to treat ITP. In this study, we reviewed the pathophysiology of ITP and summarized updates in this population's management and treatment options. We also took a closer look at the 315 ongoing trials to investigate their progress status and compare the effectiveness of interventions. May our comprehensive view of ongoing clinical trials serve as a guiding beacon, illuminating the path towards future trials of different drugs in the treatment of ITP patients.

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

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

Adverse Events Following Immunization- The Known Unknowns and Black Box : Based on 10th Dr. I. C. Verma Excellence Award for Young Pediatricians Delivered as Oration on 9th Oct. 2022

Although vaccines are one of the most rigorously tested biological products, the safety concerns persist globally. The vaccine safety concerns linked to measles, pentavalent and human papillomavirus (HPV) vaccines have affected the vaccine coverage significantly in past. While surveillance of adverse events following immunization (AEFI) is part of the national immunization program mandate, it suffers from challenges and biases related to reporting, completeness, and quality. Some conditions of concern, termed as adverse events of special interest (AESI) following vaccination, mandated specialised studies to prove/disprove the association. The AEFIs/AESIs are usually caused by one of the four pathophysiologic mechanisms, but for several AEFIs/AESIs, the exact pathophysiology remains elusive. For the causality assessment of AEFIs, a systematic process with checklists and algorithm are followed to classify into one of the four causal association categories. While the causal association primarily banks on epidemiological observations for several AEFIs, the emerging evidences indicate roles of underlying genetic, gender, age and other pro-inflammatory risk factors for AEFIs and AESIs. The emerging evidences suggest role of antigenic mimicry, autoantibody(ies) and underlying genetic susceptibility for the AEFIs/AESIs. The uncertainty about the frequency, profile, interval, and severity of AEFIs/AESIs and variations across the population, ambiguity about the exact pathophysiology mechanism, absence of definite markers, suggest a possible black box effect of the vaccines. Unless these unanswered questions concerning the AEFIs/AESIs are addressed appropriately and communicated to the stakeholders (professionals, care providers, beneficiaries, general public and media), the anti-vaccine movement shall keep challenging the vaccine and vaccination program.

Research advances in the role and pharmaceuticals of ATP-binding cassette transporters in autoimmune diseases

Autoimmune diseases are caused by the immune response of the body to its antigens, resulting in tissue damage. The pathogenesis of these diseases has not yet been elucidated. Most autoimmune diseases cannot be cured by effective drugs. The treatment strategy is to relieve the symptoms of the disease and balance the body's autoimmune function. The abnormal expression of ATP-binding cassette (ABC) transporters is directly related to the pathogenesis of autoimmune diseases and drug therapy resistance, which poses a great challenge for the drug therapy of autoimmune diseases. Therefore, this paper reviews the interplay between ABC transporters and the pathogenesis of autoimmune diseases to provide research progress and new ideas for the development of drugs in autoimmune diseases.

Pharmacokinetics, Safety, and Pharmacodynamics of Romiplostim in Chinese Subjects With Immune Thrombocytopenia: A Phase I/II Trial

Romiplostim is approved for the treatment of immune thrombocytopenia (ITP). This study aimed to evaluate the pharmacokinetics, safety, and pharmacodynamics of romiplostim in Chinese patients with ITP. This multicenter, open-label, dose-escalation phase I/II trial enrolled ITP patients from 5 centers in China between October 2015 and August 2017. There were 2 cohorts: 1 μg/kg and 3 μg/kg weekly for 2 weeks. The end points included pharmacokinetics, platelet changes from baseline, hematological indicators, and adverse events (AEs). Sixteen participants, with 8 patients in each cohort, were enrolled. In the 1 μg/kg cohort, time to maximum concentration was 4.00 (4.00-7.83) hours, maximum serum drug concentration was 52.0 (16.0-228.0) pg/mL, and area under the serum drug concentration-time curve from time 0 to the last detectable time point was 389 (32.0-5400) pg · h/mL. In the 3 μg/kg cohort, time to maximum serum drug concentration was 11.91 (4.00-12.00) hours, maximum serum drug concentration was 105.0 (25.5-313.0) pg/mL, and half-life was 12.7 (8.2-23.6) hours. The absolute change of peak platelet count from baseline was 14 (3-40) and 72 (3-369) ×10⁹ /L in the 1 and 3 μg/kg cohorts, respectively. Seven (87.5%) and eight (100%) participants had treatment-emergent AEs in 1 μg/kg cohort and 3 μg/kg cohort, respectively. No major AEs occurred in the 2 cohorts. Romiplostim (1 and 3 μg/kg) is safe and well tolerated in Chinese patients with ITP.

Helicobacter pylori induced Immune Thrombocytopenic Purpura and perspective role of Helicobacter pylori eradication therapy for treating Immune Thrombocytopenic Purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterised by production of autoantibodies against platelet surface antigens. Recent studies have demonstrated a paramount association of ITP and Helicobacter pylori (H-pylori) infection with significant rise in platelet count following H-pylori eradication therapy. The H-pylori infection induced ITP is validated by many proposed mechanisms such as molecular mimicry due to production of autoantibodies against H-pylori surface virulent factors (CagA) and cross reactivity of these antibodies with platelet surface antigens (GP IIb/IIIa, GP Ib/IX, and GP Ia/IIa), phagocytic perturbation due to enhanced phagocytic activity of monocytes, enhanced dendritic cell numbers and response, platelets aggregation due to presence of anti- H-pylori IgG and von Willebrand factor (vWf) and finally host immune response against H-pylori virulent factors CagA and VacA leading to ITP. The effectiveness of H-pylori eradication therapy has also been demonstrated with platelet count being used as a predictive factor for assessment of treatment efficacy. Out of 201 patients 118 were responding to the triple therapy and remaining 83 patients were non-responders, showing the response rate of 58.7%. Out of 118 responders 69 patients were showing complete response (CR) and 49 were showing partial response (PR) to the H-pylori eradication therapy. However, more studies are required to elucidate this association and treatment efficacy.

Response to rituximab in children and adults with immune thrombocytopenia (ITP)

BACKGROUND

Rituximab is a monoclonal anti-CD20 antibody used as a second-line treatment for immune thrombocytopenia (ITP). As additional treatments for ITP emerge, identifying the most appropriate patients and optimal timing for rituximab are important but challenging without established predictors of response to therapy.

OBJECTIVES

The purpose of this study was to describe demographic, clinical, and laboratory characteristics of pediatric and adult patients with ITP to identify differences in evaluation before rituximab administration and correlates of platelet response.

METHODS

This is a retrospective cohort study describing the characteristics of patients with ITP treated with rituximab from 2010 to 2020 at two academic tertiary care centers.

RESULTS

A total of 64 patients met criteria for inclusion. Complete rituximab response (56%) was not significantly different between children (58%, n = 24) and adults (55%, n = 40). Response rate was similar in those with primary versus secondary ITP (53% vs 62%). Among patients treated with rituximab, Evans Syndrome was more common in children than adults (42% vs 18%). Immunologic labs assessed before rituximab varied by age and were more commonly evaluated in children (lymphocyte subsets 88% vs 22%). Immunologic markers, including antinuclear antibody, direct antiglobulin testing, immunoglobulin levels, and lymphocyte subsets, did not predict response to rituximab in pediatric or adult patients with ITP.

CONCLUSIONS

Pre-rituximab immunologic evaluation varied significantly between adults and children, which could represent institution-specific practice patterns or a more general practice difference. If the latter, underlying immunodeficiency in adults with ITP may be underrecognized. Standardized guidance for pre-rituximab immunologic evaluation is needed.

Helicobacter pylori: An Underrated Cause of Immune Thrombocytopenic Purpura. A Comprehensive Review

Idiopathic thrombocytopenic purpura (ITP) is the autoimmune-mediated destruction of platelets. ITP is a diagnosis of exclusion after other identifiable etiologies have been ruled out. After the first report by Gasbarrini et al. (1998) showing rising platelet counts in ITP patients following Helicobacter pylori (HP) eradication therapy, there is growing evidence that highlights the role of HP in triggering ITP. However, the exact pathophysiology of HP-associated ITP is still unclear, but many theories have been implicated in this regard. According to various reports, the postulated mechanisms for the role of HP in cITP include molecular mimicry, increased plasmacytoid dendritic cell numbers, phagocytic perturbation, and variable host immune response to HP virulence factors. One famous theory suggested molecular mimicry between platelet surface antigen and bacterial virulence factor, i.e. cytotoxin-associated gene A (CagA). It is thought that a chronic inflammatory response following an HP infection induces the host autoantibodies' response against CagA, which cross-reacts with platelet surface glycoproteins; therefore, it may accelerate platelet destruction in the host reticuloendothelial system. However, further studies are mandated to better understand the causal link between ITP and HP and study the role of biogeography. Nowadays, it is recommended that every patient with ITP should undergo HP diagnostic testing and triple therapy should be administered in all those candidates who test positive for HP infection. In our review, there were a few pregnant female ITP patients who took HP eradication therapy mainly after 20 weeks of gestation without maternal or fetal worst outcomes. However, large-scale studies are advisable to study the adverse fetal outcomes following triple therapy use.

Comparison of treatments for persistent/chronic immune thrombocytopenia: a systematic review and network meta-analysis

Recent studies have indicated that medical options without splenectomy, such as rituximab (RTX) or thrombopoietin receptor agonists (TPO-RAs), can be effective to treat persistent or chronic primary immune thrombocytopenia (ITP). However, it remains to be determined which of these strategies should be the first choice after the first-line treatment for newly diagnosed ITP. We performed a systematic review and network meta-analysis to establish a clinically meaningful hierarchy of the efficacy and safety of medical treatments for persistent or chronic ITP in adults. Randomized controlled trials (RCTs) evaluating medical treatments were included. Reviewers independently extracted data and assessed the risk of bias. The main outcome was the overall response (platelet≥ 50 × 10⁹/L); incidence of bleeding episodes, necessity of rescue treatments, and therapy-related adverse events including thrombosis were the secondary endpoints. A total of 12 randomized controlled trials (N= 1306) were included in this study. Our main finding was an improved overall response in TPO-RA arms (both Eltrombopag and Romiplostim) compared with that of RTX or placebo. There were no significant differences between Eltrombopag and Romiplostim. Moreover, clinically significant bleeding episodes were decreased in TPO-RA arm compared with placebo. Therapy-related adverse events showed similar profiles, and were tolerable in all treatment arms. In conclusion, TPO-RAs can be first choices for the treatment of persistent and chronic ITP, rather than RTX, as alternatives to splenectomy. Future head-to-head trials including TPO-RAs vs. RTX or Eltrombopag vs. Romiplostim are necessary to validate our study findings and determine the most suitable therapy for persistent/chronic ITP.

Association between Helicobacter pylori infection and platelet count in mice

Strong evidence for an association between idiopathic thrombocytopenic purpura (ITP) and Helicobacter pylori (HP) infection has been reported in humans. Chronic ITP is known to be improved by the eradication of HP. The purpose of this study was to reproduce these events by the experimental infection of several strains of mice with HP. BALB/c, C57BL/6, and DBA/2 mice were untreated or orally inoculated with HP. Two months later, platelet counts were compared in samples from HP-infected and noninfected mice. Platelet counts (mean ± SD, × 10⁴ cells/µl) in blood samples from HP-infected BALB/c, C57BL/6, and DBA/2 mice were 102.28 ± 14.71, 99.65 ± 17.00, and 111.57 ± 16.20, respectively; the respective counts from noninfected mice were 121.80 ± 13.30, 104.35 ± 18.20, and 107.84 ± 14.33. A significant difference in platelet counts between HP-infected and noninfected mice was observed in BALB/c mice (P≤0.01) but was not observed in DBA/2 mice, even though the histocompatibility (H)-2 type of the DBA/2 was the same as that of BALB/c mice. According to ELISA results, the optical density value for the anti-HP antibody in HP-infected BALB/c mice was not correlated with the number of platelets (P>0.50). These results suggest that the decrease in platelet count caused by HP infection is not related to antibody titer and histocompatibility-2 type. Experimental infection of BALB/c mice with HP can reproduce the relationship between HP and ITP and serves as a good model to investigate the mechanistic basis for the effectiveness of HP eradication therapy for ITP treatment.

Comparison of up-front treatments for newly diagnosed immune thrombocytopenia -a systematic review and network meta-analysis

Corticosteroids such as prednisolone and dexamethasone have been established as up-front therapy for the treatment of newly diagnosed immune thrombocytopenia. Recent studies have indicated that other treatments such as rituximab or thrombopoietin receptor agonist can also be effective choices. We performed a systematic review and network meta-analysis to establish a clinically meaningful hierarchy of efficacy and safety of treatments for newly diagnosed primary immune thrombocytopenia in adults. Randomized controlled trials evaluating medical treatments for newly diagnosed immune thrombocytopenia were included. Reviewers independently extracted data and assessed the risk of bias. The main outcome was the sustained response (platelet count >30×10⁹/L for 3–6 months after completion of treatments), while overall response (platelet count >30×10⁹/L for 2–4 weeks after initiation of the up-front treatment) and therapy-related adverse events were the secondary endpoints. A total of 21 randomized controlled trials (1898 patients) were included in this study. Our main findings were a significantly better sustained response in the recombinant human thrombopoietin+dexamethasone and rituximab+dexamethasone arms compared to those of conventional therapies (prednisolone and dexamethasone monotherapy). Moreover, recombinant human thrombopoietin+dexamethasone and +prednisolone improved early overall response compared to prednisolone, dexamethasone, and rituximab-containing regimens. Therapy-related adverse events showed similar profiles and were tolerable in all treatment arms. Regimens containing recombinant human thrombopoietin agonist may be beneficial up-front therapies in addition to the conventional corticosteroid monotherapies. Future head-to-head trials including these regimens and rituximab-containing treatments are necessary in order to overcome the limitations of the small number in our study and determine the most suitable initial therapies for newly diagnosed immune thrombocytopenia.

Efficacy of Dexamethasone for Acute Primary Immune Thrombocytopenia Compared to Prednisolone: A Systematic Review and Meta-analysis

Corticosteroids have been established as first-line therapy in acute primary immune thrombocytopenia (ITP), and the clinical guidelines recommend either dexamethasone (Dex) or prednisolone (PSL). The types and dosages of corticosteroids, however, have not yet been determined, because previous randomized control trials (RCTs) comparing Dex and PSL showed controversial results in terms of efficacy. To understand and interpret all available evidence, we conducted a systematic review and meta-analysis of RCTs. The main outcome measure was the incidence of sustained response (SR; platelet count >30 × 10 ⁹ /L for 6 months without concomitant treatments after the completion of the final therapies). Eight RCTs (totaling 704 patients) were included in this study. The incidence of SR showed no significant difference, while it was significantly higher in the Dex arm when used with posttherapy (more than one course of Dex or tapering corticosteroids added; risk ratio [RR], 1.82; 95% confidence interval [CI], 1.38-2.41; p  < 0.01). A single course of Dex showed no significant difference. The overall response (platelet >30 × 10 ⁹ /L) at day 28 was significantly improved in the Dex arm (RR, 1.11; 95% CI, 1.01-1.22; p  = 0.03) and Dex with posttherapy suppressed long-term relapse (RR of nonevent, 1.32; 95% CI, 1.10-1.59; p  < 0.01). There were significantly fewer adverse events in the Dex arm (RR, 0.45; 95% CI, 0.37-0.55; p  < 0.01). Use of Dex with posttherapy instead of PSL may be more beneficial as the initial therapy. Studies comparing Dex with other new strategies are essential to determine the most suitable therapeutic regimens for acute ITP.

[Erbium laser application for oral surgery in patients with platelet hemostatic disorders]

Hemostatic disorders are typically associated with prolonged bleeding after or during surgical procedures. The aim of the study was to increase the efficiency of oral surgery in these patients using erbium laser. Selected 46 patients receiving oral surgery were randomly divided in 2 groups: 43 patients with thrombocytopenia, trombocytemia and other platelet disorders treated with erbium laser and a control group of 43 patients without concomitant pathology determined for conventional surgical treatment. No postoperative bleeding was seen in group 1. Conventional procedures were associated with significantly more postoperative pain and epithelization took 1-3 days longer. Erbium laser radiation is an up-to-date method which can be successfully used for oral surgery in patients with hemostatic disorders.

Purtscher's retinopathy as the presenting manifestation of immune thrombocytopenic purpura

Purpose

To report the case of a 52-year-old man with Purtscher's retinopathy as the presenting manifestation of immune thrombocytopenic purpura (ITP).

Observations

Treatment with corticosteroids led to the resolution of hematologic findings within 1 week, and normal visual acuity was achieved after 2 months with no additional treatment.

Conclusions and importance

This is the first reported association between Purtscher's retinopathy and ITP. Complement activation has been implicated in the pathogenesis of both ITP and Purtscher's retinopathy, and we suggest that the patient's systemic process accounted for the retinal findings.

Length of stay, hospitalization cost, and in-hospital mortality in US adult inpatients with immune thrombocytopenic purpura, 2006-2012

Purpose

In this study, we examined the length of stay, hospitalization cost, and risk of in-hospital mortality among US adult inpatients with immune thrombocytopenic purpura (ITP).

Methods

We analyzed nationally representative data obtained from Nationwide/National Inpatient Sample database of discharges from 2006 to 2012.

Results

In the US, there were an estimated 296,870 (95% confidence interval [CI]: 284,831–308,909) patient discharges recorded for ITP from 2006 to 2012, during which ITP-related hospitalizations had increased steadily by nearly 30%. The average length of stay for an ITP-related hospitalization was found to be 6.02 days (95% CI: 5.93–6.10), which is 28% higher than that of the overall US discharge population (4.70 days, 95% CI: 4.66–4.74). The average cost of ITP-related hospitalizations was found to be US$16,594 (95% CI: US$16,257–US$16,931), which is 48% higher than that of the overall US discharge population (US$11,200; 95% CI: US$11,033–US$11,368). Gender- and age-adjusted mortality risk in inpatients with ITP was 22% (95% CI: 19%–24%) higher than that of the overall US discharge population. Across diagnosis related groups, length of stay for ITP-related hospitalizations was longest for septicemia (7.97 days, 95% CI: 7.55–8.39) and splenectomy (7.40 days, 95% CI: 6.94–7.86). Splenectomy (US$25,262; 95% CI: US$24,044–US$26,481) and septicemia (US$18,430; 95% CI: US$17,353–US$19,507) were associated with the highest cost of hospitalization. The prevalence of mortality in ITP-related hospitalizations was highest for septicemia (11.11%, 95% CI: 9.60%–12.63%) and intracranial hemorrhage (9.71%, 95% CI: 7.65%–11.77%).

Conclusion

Inpatients with ITP had longer hospital stay, bore higher costs, and faced greater risk of mortality than the overall US discharge population.

Platelet count evolution as a predictor of outcome after splenectomy for immune thrombocytopenic purpura

Splenectomy is the definitive second-line therapy for refractory immune thrombocytopenic purpura (ITP), and has a reported response rate of 50-80%. Medical attention should be reconsidered when there is no evidence of accessory spleen in refractory ITP patients after splenectomy. The purpose of this study was to determine whether platelet count evolution differs between patients with a successful or unsuccessful result after splenectomy for ITP. Archived records of 104 consecutive patients that underwent splenectomy for ITP were reviewed. Patients were divided into two groups (failures and successes) using a final follow-up platelet count of 100,000/μL as a cut-off. Platelet count evolutions in these two groups were compared using the Student's t test. Successes and failures were found to have significantly different platelet counts from two days postoperatively (P = 0.016). The area under the receiver operating characteristic curve was 0.630 (95% confidence interval, 0.518-0.741, P = 0.030), and when a cut-off value of 100,000/μL was used, sensitivity and specificity were 68.2 and 51.2%, respectively. To obtain positive and negative predictive values exceeding 50%, additional platelet counts were required at one week and one month after splenectomy. We propose a protocol for ITP follow-up after splenectomy.

Therapeutic Apheresis in Hematologic, Autoimmune and Dermatologic Diseases With Immunologic Origin

The process of curing a patient by removing his illness by extracting blood is a very old one. Many years ago, phlebotomy was practiced to cure illness. Now, this old process, placed on a rational basis with therapeutic apheresis (TA), is being followed in clinical practice. Therapeutic plasma exchange (TPE) with hollow fiber modules has been used in different severe diseases for more than 40 years. Based on many years of experience with the extracorporeal circulation in end-stage renal disease, the authors herein give an overview of TA in immunological diseases, especially in hematologic, autoimmune and dermatologic diseases. Updated information on immunology and molecular biology of different immunological diseases is discussed in relation to the rationale for apheresis therapy and its place in combination with other modern therapies. With the introduction of novel and effective biologic agents, TA is indicated only in severe cases, such as in rapid progression despite immunosuppressive therapy and/or biologic agents. In mild forms of autoimmune disease, treatment with immunosuppressive therapies and/or biologic agents seems to be sufficient. The prognosis of autoimmune diseases with varying organ manifestations has improved in recent years, due in part to very aggressive therapy schemes. For the immunological diseases that can be treated with TA, the guidelines of the German Working Group of Clinical Nephrology and of the Apheresis Applications Committee of the American Society for Apheresis are cited. TA has been shown to effectively remove the autoantibodies from blood and lead to rapid clinical improvement.

Expression of IL4 (VNTR intron 3) and IL10 (-627) genes polymorphisms in childhood immune thrombocytopenic purpura

OBJECTIVE

Immune thrombocytopenic purpura (ITP) is an acquired autoimmune disorder caused by the production of antiplatelet antibodies. These autoantibodies opsonize platelets for splenic clearance, resulting in low levels of circulating platelets. Interleukin 4 (IL4) and interleukin 10 (IL10) are important immunoregulatory cytokines mainly produced by macrophages, monocytes, T cells, B cells, and mast cells. Our study was aimed at detecting the frequency of IL4 (VNTR intron 3) and IL 10 (-627) gene polymorphisms in Egyptian ITP children as genetic markers for ITP risk and clarifying their possible role in the pathogenesis of ITP as well as their correlation with the clinical presentation and laboratory data.

METHODS

IL4 (VNTR intron 3) and IL10 (-627) gene polymorphisms were studied in 70 ITP patients and 50 age- and sex-matched healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP).

RESULTS

IL4 RP2 and IL10 A alleles were detected more frequently among ITP patients compared to controls. A statistically significant difference was observed in IL10 and IL4 gene polymorphism distribution between acute and chronic ITP patients, with higher A allele and RP2 allele among chronic ITP patients versus acute ITP patients. Combined polymorphisms of IL4 and IL10 genes were associated with greater risk of ITP.

CONCLUSION

IL4 and IL10 gene polymorphisms may contribute to susceptibility for ITP in children.

Blocking neutrophil diapedesis prevents hemorrhage during thrombocytopenia

Organ hemorrhage represents a major complication in thrombocytopenia with potential fatal outcome. Hillgruber et al. demonstrate that neutrophil diapedesis through the endothelial barrier is responsible for the bleeding and could represent a therapeutic target in immune-thrombocytopenic patients.

Spontaneous organ hemorrhage is the major complication in thrombocytopenia with a potential fatal outcome. However, the exact mechanisms regulating vascular integrity are still unknown. Here, we demonstrate that neutrophils recruited to inflammatory sites are the cellular culprits inducing thrombocytopenic tissue hemorrhage. Exposure of thrombocytopenic mice to UVB light provokes cutaneous petechial bleeding. This phenomenon is also observed in immune-thrombocytopenic patients when tested for UVB tolerance. Mechanistically, we show, analyzing several inflammatory models, that it is neutrophil diapedesis through the endothelial barrier that is responsible for the bleeding defect. First, bleeding is triggered by neutrophil-mediated mechanisms, which act downstream of capturing, adhesion, and crawling on the blood vessel wall and require Gα_i signaling in neutrophils. Second, mutating Y731 in the cytoplasmic tail of VE-cadherin, known to selectively affect leukocyte diapedesis, but not the induction of vascular permeability, attenuates bleeding. Third, and in line with this, simply destabilizing endothelial junctions by histamine did not trigger bleeding. We conclude that specifically targeting neutrophil diapedesis through the endothelial barrier may represent a new therapeutic avenue to prevent fatal bleeding in immune-thrombocytopenic patients.

Tumor necrosis factor-α -308G/A gene polymorphism in Egyptian children with immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by increased platelet destruction. Although the cause of ITP remains unclear, it is accepted that both environmental and genetic factors play an important role in the development of the disease. Children with ITP have a T-helper 1-type cytokine pattern with elevated levels of tumor necrosis factor-alpha (TNF-α) as in most autoimmune diseases. Researchers have shown that polymorphism in the TNF-α gene at position -308 affects gene transcriptions with increased TNF-α production. The current case-control study aimed at detecting the frequency of TNF-α -308G/A gene polymorphism as genetic markers in Egyptian children with ITP, and to clear out their possible role in choosing the treatment protocols of therapy, using PCR restriction fragment length polymorphism assay. Ninety-two ITP patients and 100 age and sex-matched healthy controls were recruited in the study. The results obtained revealed that the frequency of TNF-α -308A/A homotype in ITP patients was significantly higher than that of the controls, and conferred almost six-fold increased risk of ITP acquisition. The polymorphic A allele frequency was significantly higher in ITP patients than in the controls, conferring almost two-fold increased ITP risk. In conclusion, our study suggests the possibility that TNF-α -308 gene polymorphism may contribute to the susceptibility of childhood ITP in Egyptian children.

Aberrant expression of RUNX3 in patients with immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease, characterized by dysregulation of cellular immunity. Previous studies demonstrated that immune imbalance between Th1 and Th2 was associated with the pathogenesis of ITP. Runt-related transcription factor 3 (RUNX3) is a member of the runt domain-containing family of transcription factors and plays an important role in the regulation of T cell differentiation into Th1 cells. Whether RUNX3 was involved in the pathogenesis of ITP remains unclear. In this study, 47 active ITP patients, 18 ITP with remission and 26 age and gender matched healthy control were included. Peripheral blood mononuclear cells (PBMCs) were isolated from ITP and control for isolation of RNA and plasma which were used to measure mRNA level of RUNX3 and T-box transcription factor (T-bet) by quantitative real-time PCR and interferon γ (IFN-γ) plasma level by ELISA. Meanwhile, protein was also extracted from PBMCs for Western blot analysis of RUNX3 expression. Our results showed a significantly higher expression of RUNX3, T-bet and plasma level of IFN-γ in active ITP patients compared to control. No differences were observed between ITP with remission and control. Furthermore, a positive correlation of RUNX3 with T-bet was found in active ITP patients. In conclusion, aberrant expression of RUNX3 was associated with the pathogenesis of ITP and therapeutically targeting it might be a novel approach in ITP treatment.

Initial Experience with the Use of Thrombopoetin Receptor Agonists in Patients with Refractory HIV-Associated Immune Thrombocytopenic Purpura: A Case Series

HIV-associated immune thrombocytopenic purpura (ITP) has decreased in incidence 10-fold since the advent of highly active antiretroviral therapy (HAART). For patients with detectable HIV viral loads, first-line treatment approaches involve optimizing HAART followed by standard ITP options used to treat those without HIV infection. In the general population, the thrombopoetin receptor agonists (TRAs), eltrombopag and romiplostim, are effective when used as salvage ITP therapy. In addition, eltrombopag has been used effectively in patients with thrombocytopenia secondary to hepatitis C--a virus seen commonly in HIV-infected patients, especially in those who also have a history of intravenous drug use. There are, however, few reports or studies of TRAs use in those with HIV infection. Herein, we describe 5 cases of refractory HIV-associated ITP managed with TRAs. Although platelet counts improved for all patients, 2 patients succumbed to thromboembolic complications. Our initial experience, as well as our findings from a Medline review, supports the potential utility of TRA as salvage therapy in the treatment of HIV-related ITP; however, we recommend caution in the use of these agents in those who are at highest risk of thrombosis. Additional studies are needed to determine the efficacy and, more importantly, the safety of TRAs in treatment of HIV-associated ITP.

Effect of thrombopoietin receptor agonists on the apoptotic profile of platelets in patients with chronic immune thrombocytopenia

Platelet survival depends upon mediators of apoptosis e.g., Bcl-xL, Bax, and Bak, which are regulated by thrombopoietin (TPO)-mediated AKT signaling. Thrombopoietin receptor (TPO-R) signaling might decrease platelet and/or megakaryocyte apoptosis and increase the platelet count. This study therefore explored anti-apoptotic effects of TPO-R-agonists in vivo on platelets of patients with immune thrombocytopenia. Patients received eltrombopag or romiplostim for two weeks. Total, immature, and large platelet counts were assessed as were Bcl-xL inhibitor assay; Bcl-xL Western blot; and flow cytometric (FACS) analysis of the AKT-signaling pathway. Eight/ten patients had platelet responses to eltrombopag and all three to romiplostim. Platelet sensitivity to apoptosis by Bcl-xL inhibition was greater in pretreatment patients than controls. This sensitivity normalized after one week of therapy, but surprisingly returned to pretreatment levels at week two. FACS analysis revealed increased AKT-pathway signaling after one week, followed by a decrease at week two. Platelet counts correlated with the Bcl-xL /Bak ratio. Platelet survival may be enhanced by TPO-R-agonists as a transient decrease in platelet sensitivity to apoptosis was accompanied by transient activation of AKT. However, this mechanism has only a short-lived effect. Megakaryocytes and platelets already present at the start of TPO-R-agonist treatment appear to respond differently than those generated de novo.

Immune thrombocytopenic purpura induced by intestinal tuberculosis in a liver transplant recipient

A variety of clinical manifestations are associated directly or indirectly with tuberculosis. Among them, haematological abnormalities can be found in both the pulmonary and extrapulmonary forms of the disease. We report a case of immune thrombocytopenic purpura (ITP) associated with intestinal tuberculosis in a liver transplant recipient. The initial management of thrombocytopenia, with steroids and intravenous immunoglobulin, was not successful, and the lack of tuberculosis symptoms hampered a proper diagnostic evaluation. After the diagnosis of intestinal tuberculosis and the initiation of specific treatment, a progressive increase in the platelet count was observed. The mechanism of ITP associated with tuberculosis has not yet been well elucidated, but this condition should be considered in cases of ITP that are unresponsive to steroids and intravenous immunoglobulin, especially in immunocompromised patients and those from endemic areas.

Comparison of anti-D immunoglobulin, methylprednisolone, or intravenous immunoglobulin therapy in newly diagnosed pediatric immune thrombocytopenic purpura

This study aimed to evaluate the efficacy, cost, and effects of anti-D immunoglobulin (anti-D Ig), methylprednisolone, or intravenous immunoglobulin (IVIG) therapy on the development of chronic disease in children who are Rh-positive with diagnosed immune thrombocytopenic purpura (ITP). Children with newly diagnosed ITP and platelet count <20,000/mm(3) were prospectively randomized to treatment with anti-D Ig (50 μg/kg), methylprednisolone (2 mg/kg/day), or IVIG (0.4 g/kg/day, 5 days). Sixty children with a mean age of 6.7 years were divided into three equal groups. No difference was observed between platelet counts before treatment and on day 3 of treatment. However, platelet counts at day 7 were lower in the methylprednisolone group than in the IVIG group (P = 0.03). In the anti-D Ig group, hemoglobin and hematocrit levels were significantly lower at the end of treatment (P < 0.05). Chronic ITP developed in 30% of the anti-D Ig group, 35% of the methylprednisolone group, and 25% of the IVIG group, but no significant difference was noted among the groups. The cost analysis revealed that the mean cost of IVIG was 7.4 times higher than anti-D Ig and 10.9 times higher than methylprednisolone. In the treatment of ITP in childhood, one 50 μg/kg dose of anti-D Ig has similar effects to IVIG and methylprednisolone. Among patients who were treated with anti-D Ig, serious anemia was not observed, and the cost of treatment was less than that of IVIG treatment.

Patterns of inpatient care for newly diagnosed immune thrombocytopenia in US children's hospitals

OBJECTIVE

Although recent evidence-based guidelines for the management of immune thrombocytopenia (ITP) recommend a conservative, observation-based approach for the majority of patients with newly diagnosed pediatric ITP, current practice patterns are unknown. This study used the Pediatric Health Information System database to examine patterns of inpatient care in newly diagnosed ITP in freestanding US children's hospitals and to examine geographic differences in care.

METHODS

Data were extracted from Pediatric Health Information System for all newly diagnosed ITP admissions aged 1 to 18 years discharged between January 2008 and December 2010. Clinical data obtained included age, gender, length of stay, diagnoses, medications, and discharge status.

RESULTS

We identified 2314 unique patients meeting the study diagnosis of newly diagnosed ITP. Noncutaneous bleeding occurred in 12% of patients (intracranial hemorrhage 0.6%), with epistaxis the most commonly reported symptom. Ninety percent of hospitalized patients received ITP-directed therapy, with intravenous immunoglobulin G the most commonly used therapy (78% of patients). We identified significant variation by geographic region in treatment strategies, length of stay, hospital charges, and likelihood of readmission.

CONCLUSIONS

A substantial number of children with newly diagnosed ITP continue to be hospitalized and receive intravenous medications, although the majority of these patients do not have clinical bleeding events during the admission. By using these results as a backdrop, future studies will be able to identify if the number of ITP admissions, costs of care, and geographic variability in care decrease with the dissemination and implementation of recently published guidelines.

Disseminated tuberculosis with immune thrombocytopenic purpura

Tuberculosis has a variety of hematological manifestations. Immune thrombocytopenic purpura is an uncommon manifestation of tuberculosis. We present a case of disseminated tuberculosis with isolated thrombocytopenia. While TB granulomas in the bone marrow can themselves cause hematological abnormalities, persistent thrombocytopenia refractory to anti-TB therapy may be ITP associated with TB.

The burden of immune thrombocytopenia in adults: evaluation of the thrombopoietin receptor agonist romiplostim

BACKGROUND

Immune thrombocytopenia (ITP) is a chronic, immune-mediated disease characterized by a transient or long-lasting decrease in platelet counts. ITP is associated with numerous serious clinical consequences. Discussed here are clinical aspects of ITP, the humanistic and economic burden of ITP, and current treatment options with a focus on romiplostim, a thrombopoietin (TPO) receptor agonist. The aim of this review is to provide decision-makers with the background information necessary to evaluate the value of romiplostim.

SCOPE

PubMed was searched for relevant, English-language papers published from January 2006 through November 2011 relating to the epidemiology and treatment options of chronic ITP, and, focusing on the TPO mimetic romiplostim, patient-reported outcomes (PRO) and economic burden. Recent select conference abstracts were also reviewed.

FINDINGS

The initial clinical management of ITP (e.g., corticosteroids, immunoglobulins) is often associated with adverse events and recommended for short-term use only. Splenectomy, a potentially curative second-line treatment, is associated with increased risks of bleeding and infection, and patients often require additional long-term drug intervention. ITP and its sequelae are associated with a substantial burden on patients' health-related quality-of-life (HRQoL) and increased medical costs. Use of TPO receptor agonists in ITP patients may represent a more efficient use of healthcare resources than existing therapies.

CONCLUSION

While this literature review is not a systematic review, e.g., it considers only approved therapies and published literature written in English, it provides a comprehensive overview of the clinical, humanistic, and economic factors that should be considered in treating ITP, particularly with new agents such as romiplostim. Among the limited number of safe and effective therapies currently available for chronic ITP, highly effective and well-tolerated medications such as romiplostim may reduce the healthcare resource utilization associated with ITP while improving patients' HRQoL.

The isotype of autoantibodies influences the phagocytosis of antibody-coated platelets in autoimmune thrombocytopenic purpura

Autoimmune thrombocytopenic purpura (AITP) is an acquired autoimmune bleeding disorder, characterized by isolated thrombocytopenia because of destruction of auto-antibody-coated platelets by Fc-receptor-mediated phagocytosis. The destruction of autoantibody-sensitized platelets by FcγR-bearing phagocytic cells and the following antigen presentation are considered to play a key role for the pathophysiology of AITP. Although different isotypes of AITP-mediating autoantibodies, e.g. IgG, IgM and IgA, are frequently found in AITP patients, their role in the pathophysiology of AITP remains unclear. Using a flow cytometric monocyte-based phagocytosis assay, we investigated the impact of disease-associated autoantibody isotype in antibody-mediated phagocytosis of platelets. Platelets, labelled with 5-chloromethyl fluorescein diacetate (CMFDA), were incubated with AITP patients' serum characterized by pure IgG or IgM antiplatelet autoantibodies. Labelled platelets were incubated with monocytes. Phagocytosis was defined as the product of percentage of CMFDA-positive monocytes and mean fluorescence intensity of CMFDA. Adherence of platelets to monocytes was quantified by anti-CD61-PerCp in a CMFDA(+) CD14(+) gate. IgG-coated platelets showed a significantly higher phagocytic index than IgM-coated platelets (mean 796 ± 157 versus 539 ± 78, P < 0.01). There were no significant differences regarding platelet adherence to monocytes. The isotype of autoantibodies influences the quantity of in vitro phagocytosis of autologous platelets by monocytes. Therefore, the AITP-mediating autoantibody isotype should be considered more carefully in pathophysiologic models and furthermore in diagnostic, therapeutic and prognostic approaches in AITP.

Eltrombopag for the treatment of immune thrombocytopenia

Chronic immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count that has persisted for more than 12 months. Patients with severe, symptomatic disease may have significant morbidity and require treatment. Historically, the underlying cause of ITP was believed to be accelerated platelet destruction by antiplatelet antibodies. Treatment options were therefore focused on reducing platelet autoantibody production or inhibiting macrophage-mediated platelet destruction. These treatments are not always effective or, at best, only have a transient effect and treatment-related adverse events often preclude their long-term use. Recently, impaired platelet production was observed in many ITP patients. Therefore, growth factor or growth factor analogs that stimulate megakaryopoiesis may be useful in ITP treatment. This article presents data on the pharmacology, clinical efficacy, safety profile and future roles of eltrombopag, an orally bioavailable, low-molecular-weight, synthetic nonpeptide thrombopoietin receptor agonist, in the treatment of ITP.

Low-dose rituximab combined with short-term glucocorticoids up-regulates Treg cell levels in patients with immune thrombocytopenia

This randomized trial was performed to investigate the efficacy of low-dose rituximab in combination with glucocorticoids for treatment of patients with immune thrombocytopenia (ITP). Sixty-two patients were randomly separated into the glucocorticoids (control) and the experimental (glucocorticoids + rituximab) groups. Patients in both groups received dexamethasone 40 mg/day on days 1-4, followed by decrements of prednisone 60, 30, 15, 10 mg/day on days 5-7, 8-14, 15-21, 22-28, respectively. Patients in the experimental group also received rituximab 100 mg on days 7, 14, 21, 28. The overall response (OR) was similar in both groups at day 28 (experimental group vs. glucocorticoids group: 80.6 vs. 74.2%, P = .938); however, sustained response (SR) was more pronounced in the experimental group as compared to that in the glucocorticoids group (77.4 vs. 38.7%, P < .001). Both groups showed similar incidence of adverse events (experimental group vs. glucocorticoids group: 9.7 vs. 6.5%, P = .325). As expected, B cell depletion was seen in the experimental group. In addition, both groups experienced a significant up-regulation in Treg cell levels, but the up-regulation in the experimental group was maintained at an even higher level and persisted a longer time than those in the glucocorticoids group. Thus, low-dose rituximab combined with short-term glucocorticoids provides an alternative treatment for ITP prior to splenectomy.

Epidemiology of paediatric immune thrombocytopenia in the General Practice Research Database

This study assessed the incidence of immune thrombocytopenia (ITP) and characteristics associated with ITP in the paediatric population using the General Practice Research Database (GPRD). Two hundred and fifty-seven paediatric ITP patients were identified out of 1145 incident patients with ITP recorded between 1990 and 2005. The age-specific incidence for ITP in paediatric patients was 4.2 per 100,000 person-years (PY) [95% confidence interval (CI): 3.7-4.8 per 100,000 PY], with a statistically significantly higher incidence in boys compared to girls aged 2-5 years [9.7 (95% CI: 7.5-12.2) per 100,000 PY vs. 4.7 (95% CI: 3.2-6.6) per 100,000 PY, respectively]. By contrast, among teenagers aged 13-17 years, the overall incidence was lower [2.4 (95% CI: 1.7-3.3) per 100,000 PY] with a similar incidence in girls and boys. There was a relationship between age and sex with ITP incidence, suggesting that patterns of disease burden differ among children and teenagers. Evidence of an infection or immunization shortly before ITP diagnosis was apparent in 52 (20.2%) and 22 (8.6%) of the 257 paediatric ITP patients, respectively. Two deaths were observed during the study period. ITP is an important although rarely fatal disease in paediatric patients and its aetiology remains unexplained in the majority of cases.

Association between drug and vaccine use and acute immune thrombocytopenia in childhood: a case-control study in Italy

Immune thrombocytopenic purpura (ITP) is an immunomediated disease characterized by a decrease in platelet count and, in its more severe forms, by bleeding symptoms. Many drugs have been implicated in the pathogenesis of drug-induced thrombocytopenia in adults; only limited data on drug-related ITP in children have been published. Our study was set up to evaluate the consistency of the association between drug and vaccine use and ITP in children. This study is part of an Italian multicentre study on adverse drug reactions in children, coordinated by the Italian National Institute of Health, which was started in November 1999 and is ongoing. The study was conducted by enrolling all children aged more than 1 month who were hospitalized through the paediatric emergency department for the following conditions: thrombocytopenia (platelet count <100 x 103/L); acute neurological disorders; non-infectious mucocutaneous diseases and vasculitis; and endoscopically confirmed gastroduodenal lesions and/or clinically defined haematemesis and melaena. Children with chronic pathologies or concomitant diagnoses of cancer or immunodeficiency were not included in our study. During hospital admission, a physician interviewed parents using a structured questionnaire. The main aim of the interview was to collect information on drug exposure in a time period of 3 weeks and vaccine exposure in a period of 6 weeks preceding hospitalization. Using a case-control study design, exposure of children with thrombocytopenia (cases) to drugs and vaccines was compared with similar exposure of children with gastroduodenal lesions and neurological disorders (controls); this allowed us to estimate the odds ratios (ORs) of the occurrence of thrombocytopenia associated with the use of drugs or vaccines. Up to December 2007, the study population included 387 cases of thrombocytopenia and 1924 controls. Despite the low platelet count, ITP was generally a mild disease, without serious bleeding in the majority of cases and associated with a short length of hospital stay. After adjusting for concurrent use of other drugs, use of the antibacterials was associated with a more than 2-fold increase in the risk of developing ITP (OR 2.4; 95% CI 1.8, 3.1). Mucolytics and NSAIDs were associated with an OR of 1.9; 95% CI 1.2, 2.9 and 1.5; 95% CI 1.0, 2.1 respectively, while paracetamol (acetaminophen) was associated with an OR of 1.5; 95% CI 1.2, 2.0. MMR vaccination was associated with an increased risk of developing ITP (OR 2.4; 95% CI 1.2, 4.7). The results of this study provide evidence for an association between ITP and exposure to selected antibacterials, NSAIDs, paracetamol, mucolytics and MMR vaccination.

Predicting response to splenectomy in children with immune thrombocytopenic purpura

PURPOSE

Predicting the response to splenectomy in children with immune thrombocytopenic purpura (ITP) continues to be a clinical challenge. The purpose of this study is to identify preoperative predictors of outcome for splenectomy in children with ITP.

METHODS

The charts of 19 children who underwent splenectomy for ITP were retrospectively reviewed. Platelet responses to treatment are categorized as complete response (CR, > or =150,000/microL), partial response (PR, > or =50,000 but <150,000/microL), or nonresponse (NR, <50,000/microL).

RESULTS

After splenectomy, 13 patients (68%) had CR, 3 (16%) had PR, and 3 (16%) had NR. No correlation existed between CR to splenectomy and any of the following: age, platelet count at diagnosis, last platelet count before splenectomy, platelet count on postoperative day 1, or responses to preoperative intravenous immunoglobulin, WinRho, or Rituximab. However, all 7 patients who had NR to a full course of steroids subsequently had CR to splenectomy. Nonresponse to steroid therapy was directly correlated with CR to splenectomy (P = .01, Fisher's Exact test). Furthermore, postsplenectomy platelet counts were inversely related to peak platelet response to steroids (correlation coefficient = -0.68, P = .01).

CONCLUSIONS

Preoperative responsiveness to steroid therapy, as measured by peak platelet count, predicts NR to splenectomy for ITP in children, whereas NR to steroid therapy is highly correlated with CR to splenectomy. These findings challenge the widely held notion that steroid responsiveness portends a favorable outcome after splenectomy.

Therapeutic approaches to secondary immune thrombocytopenic purpura

Secondary thrombocytopenia is similar to primary or idiopathic thrombocytopenia (ITP) in that it is characterized by reduced platelet production or increased platelet destruction resulting in platelet levels<60,000/microL. Thrombocytopenia can occur from secondary causes associated with chronic disorders or with disturbed immune function due to chronic infections, lymphoproliferative and myeloproliferative disorders, pregnancy, or autoimmune disorders. Diagnosis of secondary ITP in some cases is complex, and the thrombocytopenia can often be resolved by treating the underlying disorder to the extent this is possible. In most cases, treatment is focused on reducing platelet destruction, but, in some cases, treatment may also be directed at stimulating platelet production. The most problematic cases of thrombocytopenia may be seen in pregnant women. This review will address various agents and their utility in treating ITP from secondary causes; in addition, thrombocytopenia in pregnancy, ITP in immunodeficiency conditions, and drug-induced thrombocytopenia will be discussed. Unlike primary ITP, treatment often must be tailored to the specific circumstance underlying the secondary ITP, even if the condition itself is incurable.

Romiplostim

*Romiplostim is an Fc-peptide fusion protein (or 'peptibody') that stimulates megakaryopoiesis and thrombopoiesis by binding to, and activating, the thrombopoietin receptor. *Because it has no sequence homology to thrombopoietin, romiplostim theoretically avoids the risk of eliciting cross-reacting, neutralizing antibodies to thrombopoietin. *In well designed, 24-week, phase III trials, subcutaneous romiplostim was significantly more effective than placebo in achieving the primary endpoint of a protocol-defined durable platelet response in nonsplenectomized (61% vs 5%) or splenectomized (38% vs 0%) adults with chronic immune (idiopathic) thrombocytopenic purpura (ITP). *Romiplostim was also significantly more effective than placebo with regard to a number of secondary endpoints, including the proportions of patients with an overall (durable plus transient) platelet response or who required ITP rescue medications. The majority of romiplostim-treated patients receiving concurrent ITP drugs were able to reduce or discontinue these therapies. *Platelet response was maintained by most patients during longer-term treatment with romiplostim for up to 3 or 4 years in an open-label extension study. *Romiplostim was generally well tolerated. Almost all adverse events in the phase III studies were of mild-to-moderate intensity; most were unrelated to treatment. Longer-term treatment with romiplostim had an adverse event profile consistent with that observed in the phase III studies.

Fc receptors in immune thrombocytopenias: a target for immunomodulation?

In autoimmune disease, Fc receptors (FcRs) form the interface between immune effector cells and their antibody-coated targets, and as such are attractive targets for immunomodulatory therapy. In this issue of the JCI, two highly novel studies of Fc-FcR interactions provide new insights into the role of FcRs in immune thrombocytopenia. Asahi et al. utilized a comprehensive platform of immunological assays to examine the mechanism underlying Helicobacter pylori-associated immune thrombocytopenic purpura, and Ghevaert et al. describe a specially designed antibody that saturates binding sites on fetal platelets without initiating FcgammaR-mediated platelet phagocytosis, preventing the binding of pathological maternal anti-HLA antibodies that cause fetomaternal alloimmune thrombocytopenia (see the related articles beginning on pages 2939 and 2929, respectively). These reports illustrate how a remarkably detailed molecular understanding of the FcR network may translate into new therapeutic strategies with high clinical impact.