Piecing together the humoral and cellular mechanisms of immune thrombocytopenia

Impact of pre-delivery medication treatment on delivery outcome in patients with primary immune thrombocytopenia: a cohort study

BACKGROUND

Clinical research data showed a series of adverse events in the delivery period of primary immune thrombocytopenia (ITP) patients, including high cesarean section rate. Consensus report proposed that for patients with platelet count below 50 × 109/L, prednisone or intravenous immunoglobulins (IVIg) can be given to raise the platelet count in third trimester in preparation for labor.

OBJECTIVES

To evaluate the effect of low-dose prednisone or IVIg therapy on delivery outcomes in patients with ITP.

STUDY DESIGN

This was a cohort study that included pregnant women with ITP from January 2017 to December 2022. Patients with platelet counts of (20-50) ×109/L at the time of delivery (≥34 weeks) and who had not received any medication before were enrolled in the study. Patients were divided into the pre-delivery medication group (oral prednisone or IVIg) and untreated group according to their preferences. The differences in vaginal delivery rate, postpartum bleeding rate, and platelet transfusion volume between the two groups were compared using t-test, Wilcoxon rank-sum test, and χ2 test. Logistic regression analysis was used to identify the factors affecting vaginal delivery rate and postpartum bleeding rate, and multiple linear regression analysis was used to identify the factors affecting platelet transfusion volume.

RESULTS

During the study period, a total of 96 patients with ITP were enrolled, including 70 in the pre-delivery medication group and 26 in the untreated group. The platelet count of pre-delivery medication group was 54.8 ± 34.5 × 109/L, which was significantly higher than that of untreated group 34.4 ± 9.0 × 109/L (p = .004). The vaginal delivery rate of the medication group was higher than the untreated group [60.0% (42/70) vs. 30.8% (8/26), χ2 = 6.49, p = .013]. After adjusting for the proportion of multiparous women and gestational weeks, the results showed that medication therapy during the peripartum period was associated with vaginal delivery (OR = 4.937, 95% CI: 1.511-16.136, p = .008). The postpartum bleeding rates were 22.9% (16/70) and 26.9% (7/26) in the medication group and untreated group, respectively, with no significant difference between the two groups (χ2 = 0.17, p = .789), while the platelet transfusion volume was lower in the medication group than untreated group [(1.1 ± 1.0) vs. (1.6 ± 0.8) U].

CONCLUSION

Pre-delivery medication therapy can increase vaginal delivery rate, reduce platelet transfusion volume, but does not decrease the incidence of postpartum hemorrhage.

Construction of a clinical prediction model for the diagnosis of immune thrombocytopenia based on clinical laboratory parameters

PURPOSE

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by isolated thrombocytopenia that is often misdiagnosed due to the lack of a gold standard for diagnosis and currently relies on exclusionary approaches. This project combines several laboratory parameters to construct a clinical prediction model for adult ITP patients.

METHODS

A total of 428 patients with thrombocytopenia who visited the West China Hospital of Sichuan University between January 2021 and March 2023 were enrolled. Based on the diagnostic criteria, we divided those patients into an ITP group and a non-ITP group. A total of 34 laboratory parameters were analyzed via univariate analysis and correlation analysis, and the least absolute shrinkage and selection operator regression analysis was used to establish the model. The training and validation sets were divided at a ratio of 7:3, and we used a fivefold cross-validation method to construct the model.

RESULTS

The model included the following variables: red blood cell, mean corpuscular hemoglobin concentration, red blood cell distribution width-standard deviation, platelet variability index score, immature platelet fraction, lymphocyte absolute value. The prediction model exhibited good performance, with a sensitivity of 0.89 and a specificity of 0.83 in the training set and a sensitivity of 0.90 and a specificity of 0.87 in the validation set.

CONCLUSION

The clinical prediction model can assess the probability of ITP in thrombocytopenic patients and has good predictive accuracy for the diagnosis of ITP.

E3 ubiquitin ligase casitas B-lineage lymphoma-b modulates T-cell anergic resistance via phosphoinositide 3-kinase signaling in patients with immune thrombocytopenia

BACKGROUND

The E3 ubiquitin ligase casitas B-lineage lymphoma-b (CBLB) is a newly identified component of the ubiquitin-dependent protein degradation system and is considered an important negative regulator of immune cells. CBLB is essential for establishing a threshold of T-cell activation and regulating peripheral T-cell tolerance through various mechanisms. However, the involvement of CBLB in the pathogenesis of immune thrombocytopenia (ITP) is unknown.

OBJECTIVES

We aimed to investigate the expression and role of CBLB in CD4+ T cells obtained from patients with ITP through quantitative proteomics analyses.

METHODS

CD4+ T cells were transfected with adenoviral vectors overexpressing CBLB to clarify the effect of CBLB on anergic induction of T cells in patients with ITP. DNA methylation levels of the CBLB promoter and 5' untranslated region (UTR) in patient-derived CD4+ T cells were detected via MassARRAY EpiTYPER assay (Agena Bioscience).

RESULTS

CD4+ T cells from patients with ITP showed resistance to anergic induction, highly activated phosphoinositide 3-kinase-protein kinase B (AKT) signaling, decreased CBLB expression, and 5' UTR hypermethylation of CBLB. CBLB overexpression in T cells effectively attenuated the elevated phosphorylated protein kinase B level and resistance to anergy. Low-dose decitabine treatment led to significantly elevated levels of CBLB expression in CD4+ T cells from 7 patients showing a partial or complete response.

CONCLUSION

These results indicate that the 5' UTR hypermethylation of CBLB in CD4+ T cells induces resistance to T-cell anergy in ITP. Thus, the upregulation of CBLB expression by low-dose decitabine treatment may represent a potential therapeutic approach to ITP.

Novel Biomarkers for Diagnosis and Monitoring of Immune Thrombocytopenia

Lower-than-normal platelet counts are a hallmark of the acquired autoimmune illness known as immune thrombocytopenia, which can affect both adults and children. Immune thrombocytopenia patients' care has evolved significantly in recent years, but the disease's diagnosis has not, and it is still only clinically achievable with the elimination of other causes of thrombocytopenia. The lack of a valid biomarker or gold-standard diagnostic test, despite ongoing efforts to find one, adds to the high rate of disease misdiagnosis. However, in recent years, several studies have helped to elucidate a number of features of the disease's etiology, highlighting how the platelet loss is not only caused by an increase in peripheral platelet destruction but also involves a number of humoral and cellular immune system effectors. This made it possible to identify the role of immune-activating substances such cytokines and chemokines, complement, non-coding genetic material, the microbiome, and gene mutations. Furthermore, platelet and megakaryocyte immaturity indices have been emphasized as new disease markers, and prognostic signs and responses to particular types of therapy have been suggested. Our review's goal was to compile information from the literature on novel immune thrombocytopenia biomarkers, markers that will help us improve the management of these patients.

Association of PTPN22 SNP1858 (rs2476601) and Gene SNP1123 (rs2488457) Polymorphism With Primary Immune Thrombocytopenia Susceptibility: A Meta-Analysis of Case-Control Studies and Trial Sequential Analysis

Objective: Systematic review of the association of protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene 1858 and 1123 sites single nucleotide polymorphism (SNP) with the susceptibility of primary immune thrombocytopenia (ITP).

Method: Database searched includes PubMed, Embase, Web of Science, CNKI, CBM, VIP and WanFang Data. The retrieval period is from the establishment of the database to 30 June 2021. After screening articles according to inclusion and exclusion criteria, the data were extracted and methodological quality of the included studies was evaluated. Meta-analysis was performed using RevMan 5.4 and Stata 16.0 software. The combined OR value and its 95%CI were calculated. Sensitivity analysis and publication bias assessment were performed. Trial sequential analysis (TSA) was performed using TSA 0.9.5.10 Beta software.

Results: A total of 10 studies with 10 articles were included, with a total of 932 cases and 2,112 controls. The results of meta-analysis showed that for SNP1858, the susceptibility of TT genotype to ITP was 5.01 times higher than CC genotype [95%CI (1.81, 13.86), p = 0.002]. For SNP1123, G allele carriers were more susceptible to ITP than C allele carriers [OR = 1.23, 95%CI (1.05, 1.45), p = 0.01], and GG genotype carriers were 1.51 times more susceptible to ITP than CC genotype carriers [95%CI (1.11, 2.06), p = 0.009]. Although the results are statistically significant, the results of sensitivity analysis showed certain limitations of stability, and the TSA analysis still indicated the possibility of false positive. No significant publication bias was observed.

Conclusion: PTPN22 gene SNP1858 (rs2476601) and SNP1123 (rs2488457) polymorphisms are associated with susceptibility to primary immune thrombocytopenia. Due to the limitation of the number and quality of the included studies, the above conclusions need to be verified by more high-quality studies.

Prednisone plus IVIg compared with prednisone or IVIg for immune thrombocytopenia in pregnancy: a national retrospective cohort study

Background:

The responses of intravenous immunoglobulin (IVIg) or corticosteroids as the initial treatment on pregnancy with ITP were unsatisfactory. This study aimed to assess the safety and effectiveness of prednisone plus IVIg versus prednisone or IVIg in pregnant patients with immune thrombocytopenia (ITP).

Methods:

Between 1 January 2010 and 31 December 2020, 970 pregnancies diagnosed with ITP at 19 collaborative centers in China were reviewed in this observational study. A total of 513 pregnancies (52.89%) received no intervention. Concerning the remaining pregnancies, 151 (33.04%) pregnancies received an initial treatment of prednisone plus IVIg, 105 (22.98%) pregnancies received IVIg alone, and 172 (37.64%) pregnancies only received prednisone.

Results:

Regarding the maternal response to the initial treatment, no differences were found among the three treatment groups (41.1% for prednisone plus IVIg, 33.1% for prednisone, and 38.1% for IVIg). However, a significant difference was observed in the time to response between the prednisone plus IVIg group (4.39 ± 2.54 days) and prednisone group (7.29 ± 5.01 days; p  < 0.001), and between the IVIg group (6.71 ± 4.85 days) and prednisone group (p < 0.001). The median prednisone duration in the monotherapy group was 27 days (range, 8–195 days), whereas that in the combination group was 14 days (range, 6–85 days). No significant differences were found among these three treatment groups in neonatal outcomes, particularly concerning the neonatal platelet counts. The time to response in the combination treatment group was shorter than prednisone monotherapy. The duration of prednisone application in combination group was shorter than prednisone monotherapy. The combined therapy showed a lower predelivery platelet transfusion rate than IVIg alone.

Conclusion:

These findings suggest that prednisone plus IVIg may represent a potential combination therapy for pregnant patients with ITP.

Platelet variability index: a measure of platelet count fluctuations in patients with immune thrombocytopenia

Fluctuations in platelet count levels over time may help distinguish immune thrombocytopenia (ITP) from other causes of thrombocytopenia. We derived the platelet variability index (PVI) to capture both the fluctuations in platelet count measurements and the severity of the thrombocytopenia over time. Raw PVI values, ranging from negative (less severe thrombocytopenia and/or low fluctuations) to positive (more severe thrombocytopenia and/or high fluctuations) were converted to an ordinal PVI score, from 0 to 6. We evaluated the performance characteristics of the PVI score for consecutive adults with thrombocytopenia from the McMaster ITP Registry. We defined patients with definite ITP as those who achieved a platelet count response after treatment with intravenous immune globulin or high-dose corticosteroids and possible ITP as those who never received ITP treatment or did not respond to treatment. Of 841 patients with thrombocytopenia, 104 had definite ITP, 398 had possible ITP, and 339 had non-ITP thrombocytopenia. For patients with definite ITP, the median PVI score was 5 [interquartile range (IQR) 5, 6] for patients with possible ITP, the median PVI score was 3 (1, 5); and for patients with non-ITP thrombocytopenia, the median PVI score was 0 (0, 2). A high PVI score correlated with the diagnosis of definite ITP even when calculated at the patient's initial assessment, before any treatment had been administered. Platelet count fluctuations alone contributed to the specificity of the overall PVI score. The PVI score may help clinicians diagnose ITP among patients who present with thrombocytopenia for evaluation.

Fostamatinib: a review of its clinical efficacy and safety in the management of chronic adult immune thrombocytopenia

Management of chronic immune thrombocytopenia (ITP) is going through a transition, with the main driving forces being a better understanding of the disease, recognition that platelet count is less important than bleeding symptoms, and the availability of new therapies. The heterogeneity of chronic ITP makes treatment challenging, and highlights the need for a personalized approach. A key aspect of tailored treatment is the availability of agents to target specific underlying pathophysiological mechanisms. In this review, we examine the evidence for orally bioavailable fostamatinib and its active moiety, tamatinib (R406), which has been approved for the treatment of chronic adult ITP. Fostamatinib inhibits FcR-triggered, Syk-dependent cytoskeletal rearrangement during phagocytosis and, as such, represents an active therapy targeting a previously unexplored mechanism of ITP pathogenesis.

Idiopathic thrombocytopenic purpura (ITP) - new era for an old disease

Immune thrombocytopenia is an autoimmune hematological disorder characterized by severely decreased platelet count of peripheral cause: platelet destruction via antiplatelet antibodies which may also affect marrow megakaryocytes. Patients may present in critical situations, with cutaneous and/or mucous bleeding and possibly life-threatening organ hemorrhages (cerebral, digestive, etc.) Therefore, rapid diagnosis and therapeutic intervention are mandatory. Corticotherapy represents the first treatment option, but as in any autoimmune disorder, there is a high risk of relapse. Second line therapy options include: intravenous immunoglobulins, thrombopoietin receptor agonists, rituximab or immunosuppression, but their benefit is usually temporary. Moreover, the disease generally affects young people who need repeated and prolonged treatment and hospitalization and therefore, it is preferred to choose a long term effect therapy. Splenectomy - removal of the site of platelet destruction - represents an effective and stable treatment, with 70-80% response rate and low complications incidence. A challenging situation is the association of ITP with pregnancy, which further increases the risk due to the immunodeficiency of pregnancy, major dangers of bleeding, vital risks for mother and fetus, potential risks of medication, necessity of prompt intervention in the setting of specific obstetrical situations - delivery, pregnancy loss, obstetrical complications, etc. We present an updated review of the current clinical and laboratory data, as well as a detailed analysis of the available therapeutic options with their benefits and risks, and also particular associations (pregnancy, relapsed and refractory disease, emergency treatment).

Novel scientific approaches and future research directions in understanding ITP

Diagnosis of immune thrombocytopenia (ITP) and prediction of response to therapy remain significant and constant challenges in hematology. In patients who present with ITP, the platelet count is frequently used as a surrogate marker for disease severity, and so often determines the need for therapy. Although there is a clear link between thrombocytopenia and hemostasis, a direct correlation between the extent of thrombocytopenia and bleeding symptoms, especially at lower platelet counts is lacking. Thus, bleeding in ITP is heterogeneous, unpredictable, and nearly always based on a multitude of risk factors, beyond the platelet count. The development of an evidence-based, validated risk stratification model for ITP treatment is a major goal in the ITP community and this review discusses new laboratory approaches to evaluate the various pathobiologies of ITP that may inform such a model.

All-trans retinoic acid protects mesenchymal stem cells from immune thrombocytopenia by regulating the complement-interleukin-1β loop

Enhanced peripheral complement activation has long been considered as one of the major pathogenic elements of immune thrombocytopenia. A dysfunctional bone marrow microenvironment, especially with regards to mesenchymal stem cells, has been observed in patients with immune thrombocytopenia. However, the potential role of the complement system in the dysfunctional bone marrow microenvironment remains poorly understood. In this study, bone marrow samples from patients with immune thrombocytopenia were divided into two groups based on whether or not complement components were deposited on the surfaces of their mesenchymal stem cells. The mesenchymal cells from the group with complement deposition were less numerous, dysfunctional, had a reduced capacity to proliferate, and showed increased apoptosis as well as abnormal secretion of interleukin-1β and C-X-C motif chemokine ligand 12. In vitro treatment with all-trans retinoic acid increased the number and improved the function of the complement-positive bone marrow mesenchymal stem cells by upregulating DNA hypermethylation of the interleukin-1β promoter. In vivo studies showed that all-trans retinoic acid could rescue the impaired mesenchymal stem cells to support the thrombopoietic niche in both patients with immune thrombocytopenia and a murine model of this disease. Taken together, these results indicate that impairment of mesenchymal stem cells, mediated by the complement-interleukin-1β loop, plays a role in the pathogenesis of immune thrombocytopenia. All-trans retinoic acid represents a promising therapeutic approach in patients with immune thrombocytopenia through its effect of repairing mesenchymal stem cell impairment.

Flow cytometry and immune thrombocytopenic purpura

Although Immune thrombocytopenic purpura is a common disorder that family physicians, internists and hematologists face in their everyday practice, its diagnosis rests only on "exclusion" and its therapy is based on algorithms where "trial and error" is the rule. Flow cytometry, if simplified and standardized, could provide a quicker and better diagnostic accuracy. Studies of the lymphocyte subset using flow cytometry and more elaborate immune studies are paving the way for a better understanding of the disease and in identification of prognostic markers. Such studies may even help stratify the first-line therapy responder and assist in the use of the arsenal of immune suppressive therapy with better precision.

Diminished expression of β2-GPI is associated with a reduced ability to mitigate complement activation in anti-GPIIb/IIIa-mediated immune thrombocytopenia

Anti-GPIIb/IIIa-mediated complement activation has been reported to be important in the pathogenesis of immune thrombocytopenia (ITP). However, the role of the complement system and the involved regulatory mechanism remain equivocal. Beta2-glycoprotein I (β2-GPI), known as the main target for antiphospholipid autoantibodies, has been demonstrated as a complement regulator. Here, we investigated the complement-regulatory role of β2-GPI in anti-GPIIb/IIIa-mediated ITP. Plasma complement activation and enhanced complement activation capacity (CAC) were found in ITP patients with anti-GPIIb/IIIa antibodies in vivo and in vitro. Diminished plasma levels of β2-GPI were shown in patients of this group, which was inversely correlated with C5b-9 deposition. C5b-9 generation was inhibited by approximate physiological concentrations of β2-GPI, in a dose-dependent manner. Inhibition of C3a generation by β2-GPI and the existence of β2-GPI/C3 complexes in plasma indicated a regulation on the level of the C3 convertase. Furthermore, β2-GPI down-regulated the phosphorylation levels of c-Jun N-terminal kinase (JNK) and cleavage of BH3 interacting domain death agonist (Bid) and ultimately harbored platelet lysis. Our findings may provide a novel link between diminished plasma levels of β2-GPI and enhanced complement activation, indicating β2-GPI as a potential diagnostic biomarker and therapeutic target in the treatment of anti-GPIIb/IIIa-mediated ITP.

Impaired Function of Bone Marrow Mesenchymal Stem Cells from Immune Thrombocytopenia Patients in Inducing Regulatory Dendritic Cell Differentiation Through the Notch-1/Jagged-1 Signaling Pathway

Immune thrombocytopenia (ITP) is an autoimmune disease in which dendritic cells (DCs) play a crucial role in the breakdown of self-tolerance. Studies have identified the function of mesenchymal stem cells (MSCs) in promoting the development of regulatory DCs (regDCs). Our previous work revealed that MSCs in ITP exerted senescence, apoptosis, and impaired immunosuppressive effects on T and B cells. However, it is unclear whether the effects of MSCs on regDC induction are altered in ITP. Our data demonstrated that MSCs in ITP were impaired in inhibiting CD1a⁺ DC and CD14⁺ DC differentiation from CD34⁺ hematopoietic progenitor cells (CD34⁺ HPCs). DCs differentiated with MSCs in ITP exhibited an increased expression of costimulatory molecules CD80/CD86 and secretion of proinflammatory interleukin-12 (IL-12). Accordingly, the tolerogenic characteristics were deficient in DCs induced by MSCs in ITP. DCs differentiated with MSCs in ITP exhibited an impaired ability to inhibit CD3⁺ T cell proliferation, to suppress T helper (Th)1 cell differentiation, and to induce anergic and regulatory T cells (Tregs). The expression of Notch signaling components was measured in MSCs in ITP. Reduced expression of the ligand Jagged-1, the receptor Notch-1 intracellular domain (NICD-1), and the target gene Hes-1 was identified in MSCs in ITP. The addition of biologically active Jagged-1 to CD34⁺ HPCs was observed to promote regDC differentiation. When cultured on Jagged-1-coated plates, MSCs in ITP showed an enhancement of the Notch-1 pathway activation, Jagged-1 expression, and the function in inducing regDCs. Pretreatment with all-trans retinoic acid (ATRA) was found to partially restore the capacity of MSCs in both ITP patients and healthy controls in inducing CD34⁺-derived regDCs. Our data elucidated that MSCs in ITP were impaired in inducing CD34⁺-regDCs, associated with the Notch-1/Jagged-1 signaling pathway. ATRA could partially correct the impairment of MSCs, suggesting that ATRA could serve as a potential therapeutic alternative for ITP.

Fostamatinib for persistent/chronic adult immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by phagocytosis and destruction of autoantibody-coated platelets via spleen tyrosine kinase (Syk)-mediated signal transduction in macrophages. Effectiveness of existing therapies varies, and even leading treatments (e.g., IVIg, splenectomy, rituximab, thrombopoietic agents) do not provide optimal management for a substantial number of patients with chronic ITP. Fostamatinib disodium is an orally-bioavailable investigational agent being developed for treatment of primary persistent/chronic adult ITP. Fostamatinib inhibits FcR-triggered, Syk-dependent cytoskeletal rearrangement during phagocytosis. Promising findings have been described in several autoimmune diseases, including rheumatoid arthritis, and sustained responses with manageable adverse events observed with ongoing treatment in patients with heavily treated chronic ITP. Fostamatinib represents an active therapy targeting a previously unexplored mechanism of ITP pathogenesis.

Vaccination and autoimmune diseases: is prevention of adverse health effects on the horizon?

Autoimmune diseases, including multiple sclerosis and type 1 diabetes mellitus, affect about 5% of the worldwide population. In the last decade, reports have accumulated on various autoimmune disorders, such as idiopathic thrombocytopenia purpura, myopericarditis, primary ovarian failure, and systemic lupus erythematosus (SLE), following vaccination. In this review, we discuss the possible underlying mechanisms of autoimmune reactions following vaccinations and review cases of autoimmune diseases that have been correlated with vaccination. Molecular mimicry and bystander activation are reported as possible mechanisms by which vaccines can cause autoimmune reactions. The individuals who might be susceptible to develop these reactions could be especially not only those with previous post-vaccination phenomena and those with allergies but also in individuals who are prone to develop autoimmune diseases, such as those with a family history of autoimmunity or with known autoantibodies, and the genetic predisposed individuals. Further research is encouraged into the direct associations between vaccines and autoimmune conditions, and the biological mechanisms behind them.

Cytokine-induced killer cell therapy-associated idiopathic thrombocytopenic purpura: rare but noteworthy

Idiopathic thrombocytopenic purpura (ITP) is characterized by a diminished platelet count, an autoimmune condition with antibodies against platelets and an increased tendency to bleed. The association between ITP and solid tumors is uncommon. Cytokine-induced killer (CIK) cell therapy is a well tolerated and promising cancer treatment with minimal toxicity. For the first time, CIK cell therapy was reported to be followed by ITP. The mechanism through which CIK induces ITP remains unclear. Imbalanced ratio of Th cells, decreased numbers or impaired function of Treg cells and excessive secretion of cytokines inducing abnormal activation of B cells may be among the possible reasons. Therefore, a better understanding of this rare condition will require further investigation of these cases.

Overall conceptual framework for studying the genetics of autoimmune diseases following vaccination: a regulatory perspective

The US Vaccine Adverse Event Reporting System contains case reports of autoimmune diseases (ADs) occurring following vaccinations. ADs are rare and occur in unvaccinated people, making the potential association between vaccines and ADs challenging to evaluate. Developing mechanistic pathways that link genes, immune mediators, vaccine components and ADs would be helpful for hypothesis generation, enhancing theories of biologic plausibility and grouping rare autoimmune adverse events to increase the ability to detect and evaluate safety signals. Here, we propose a conceptual framework for investigating the genetics of ADs as safety signals following vaccination, potentially contributing to the identification of relevant biomarkers. We also discuss a study design that incorporates genetic information into postmarket clinical evaluation of autoimmune adverse events following vaccination.

Contributions of T lymphocyte abnormalities to therapeutic outcomes in newly diagnosed patients with immune thrombocytopenia

T cell abnormalities have been reported to play an important role in pathogenesis of immune thrombocytopenia (ITP) besides specific autoantibodies towards platelet. The aim of this study was to explore the clinical importance of T lymphocyte subsets in adult patients with newly diagnosed ITP before and after first-line treatment. Elderly ITP patients were also studied and we tried to analyze the relationships between these items and therapeutic outcomes. The patients were treated with intravenous immunoglobulin (IVIG) plus corticosteroids and therapeutic responses were evaluated. As a result, compared with the controls, absolute lymphocyte counts in ITP patients decreased significantly before treatment. After treatment, lymphocyte counts restored to control level regardless of their treatment outcomes. In addition, we observed increased IgG and CD19+ cell expression and decreased CD4+/CD8+ cell ratio in both whole ITP group and elderly group before treatment. After treatment, the increased IgG and CD19+ cell expression could be reduced in both respond and non-respond group regardless of patient age, while CD4+/CD8+ cell ratio could not be corrected in non-respond ITP patients. In non-respond ITP patients, increased CD8+ cell expression was noticed and could not be corrected by first-line treatment. Furthermore, even lower NK cell expression was found in non-respond elderly patients after treatment when compared with that in controls. Our findings suggest that ITP patients usually had less numbers of peripheral lymphocytes and patients with higher levels of CD8+ cells or lower levels of CD4+/CD8+ cell ratio were less likely to respond to first-line treatment. Lower levels of NK cells made therapies in elderly ITP patients even more difficult.

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

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

TNF-α promoter single nucleotide polymorphisms and haplotypes associate with susceptibility of immune thrombocytopenia in Chinese adults

OBJECTIVE

Tumor necrosis factor-alpha (TNF-α) participates as a candidate susceptibility factor for immune thrombocytopenia (ITP). This study attempted to investigate the association between five single nucleotide polymorphisms (SNPs) spanning the TNF-α promoter and the susceptibility of primary ITP in Chinese Han adults.

METHODS

In 215 adult primary ITP patients and 206 healthy controls, SNPs were detected by PCR-RFLP and PCR-SSP. The χ(2) test or fisher's exact test was used to compare frequencies of genotypes and alleles between patients and controls. Haplotypes were analyzed with the SHEsis online program. TNF-α, IFN-γ and Galectin-9 mRNA of 35 newly diagnosed adult ITP patients and 35 healthy controls were detected by qRT-PCR.

RESULTS

The haplotype GGC (-238G/-308G/-857C) of TNF-α promoter was significantly associated with a decreased susceptibility of primary ITP, especially in males. The relative levels of mRNA expression of TNF-α, IFN-γ and Gal-9 in adult active primary ITP patients was significantly up-regulated compared with patients in remission and controls.

CONCLUSIONS

This study represented the first report that the haplotype GGC of TNF-α was differentially associated with the susceptibility of primary ITP in Chinese Han adults. The up-regulation of TNF-α, IFN-γ and Galectin-9 was significantly correlated with active primary ITP in adult patients.

Redox control of platelet functions in physiology and pathophysiology

SIGNIFICANCE

An imbalance between the production and the detoxification of reactive oxygen species and reactive nitrogen species (ROS/RNS) can be implicated in many pathological processes. Platelets are best known as primary mediators of hemostasis and can be either targets of ROS/RNS or generate radicals during cell activation. These conditions can dramatically affect platelet physiology, leading even, as an ultimate event, to the cell number modification. In this case, pathological conditions such as thrombocytosis (promoted by increased cell number) or thrombocytopenia and myelodysplasia (promoted by cell decrease mediated by accelerated apoptosis) can occur.

RECENT ADVANCES

Usually, in peripheral blood, ROS/RNS production is balanced by the rate of oxidant elimination. Under this condition, platelets are in a nonadherent "resting" state. During endothelial dysfunction or under pathological conditions, ROS/RNS production increases and the platelets respond with specific biochemical and morphologic changes. Mitochondria are at the center of these processes, being able to both generate ROS/RNS, that drive redox-sensitive events, and respond to ROS/RNS-mediated changes of the cellular redox state. Irregular function of platelets and enhanced interaction with leukocytes and endothelial cells can contribute to pathogenesis of atherosclerotic and thrombotic events.

CRITICAL ISSUES

The relationship between oxidative stress, platelet death, and the activation-dependent pathways that drive platelet pro-coagulant activity is unclear and deserves to be explored.

FUTURE DIRECTIONS

Expanding knowledge about how platelets can mediate hemostasis and modulate inflammation may lead to novel and effective therapeutic strategies for the long and growing list of pathological conditions that involve both thrombosis and inflammation.

Immune Thrombocytopenia

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

Immune thrombocytopenia

Immune thrombocytopenia (ITP) is a common hematologic disorder characterized by isolated thrombocytopenia. ITP presents as a primary or a secondary form. ITP may affect individuals of all ages, with peaks during childhood and in the elderly, in whom the age-specific incidence of ITP is greatest. Bleeding is the most common clinical manifestation of ITP. The pathogenesis of ITP is complex, involving alterations in humoral and cellular immunity. Corticosteroids remain the most common first line therapy for ITP. This article summarizes the classification and diagnosis of primary and secondary ITP, as well as the pathogenesis and options for treatment.

Sustained remissions of immune thrombocytopenia associated with the use of thrombopoietin receptor agonists

BACKGROUND

Thrombopoietin receptor agonists (TRAs) are effective treatments for immune thrombocytopenia (ITP). However, continuous therapy is generally required to maintain platelet (PLT) count responses.

STUDY DESIGN AND METHODS

In this case series, we describe ITP patients from our practice who achieved durable responses to the TRAs romiplostim and eltrombopag. Patients were classified as having a definite TRA-induced remission if PLT counts increased above 100 × 10(9) /L after TRA treatment and remained above 100 × 10(9) /L even after the medication was discontinued; or a possible TRA-induced remission if PLT counts increased above 100 × 10(9) /L, remained elevated for at least 3 months after the medication was discontinued, but a subsequent relapse occurred or the effect of other disease-modifying therapies could not be excluded.

RESULTS

Of 31 patients with chronic ITP treated with TRAs in our practice, nine patients achieved a PLT count response with either romiplostim (n = 6) or eltrombopag (n = 3) that was maintained even after the medications were discontinued. Three patients met criteria for a definite TRA-induced remission, each after exposure to romiplostim. Patients had ITP for a median of 7.8 years and had failed a median of four prior therapies including eight patients who had a splenectomy. We documented a progressive decline in anti-glycoprotein IIbIIIa PLT autoantibodies in one patient while on treatment.

CONCLUSION

Some patients with ITP can achieve sustained PLT count responses after the use of TRAs. This observation raises the possibility that these agents may restore immune tolerance to PLT antigens in some patients and supports the practice of down titrating the dose.