Dapsone for paediatric chronic immune thrombocytopenia: Short report from a tertiary centre in South India.

Immune thrombocytopenia (ITP) resolves in most children within 3-12 months of diagnosis. Chronic ITP affects 10%-20% of patients, some of whom require treatment. Several second-line agents are efficacious in this group of patients. This paper describes our experience of using dapsone as a single second-line agent in children with chronic ITP. One hundred and three children with chronic ITP were seen at our centre from January 2012 to December 2016. Forty-five children met the inclusion criteria and received dapsone; 17 (37.8%) were boys; and 28 (62.2%) were girls. Early response to dapsone was seen in 37.8% of patients. The median duration of long-term follow-up was 50 months, and at least a partial response was seen in 64.4% of the patients. Dapsone offers good initial response rates and sustained remission in paediatric chronic ITP, comparable to other therapeutic agents available.

Systemic immunosuppression depletes peripheral blood regulatory B cells in patients with immune thrombocytopenia.

Regulatory B (Breg) cells are potentially implicated in the pathogenesis of immune thrombocytopenia (ITP). We analysed a prospective cohort of newly diagnosed steroid naïve ITP patients enrolled in the multicentre FLIGHT trial and found that the numbers of Bregs in their peripheral blood were similar to healthy controls. In contrast, Breg numbers were significantly reduced in ITP patients treated with systemic immunosuppression (glucocorticoids or mycophenolate mofetil). We also demonstrate that glucocorticoid treatment impairs Breg interleukin-10 production via an indirect T-cell-mediated mechanism.

Could machine learning revolutionize how we treat immune thrombocytopenia?

The absence of reliable biomarkers in immune thrombocytopenia (ITP) complicates treatment choice, necessitating a trial-and-error approach. Machine learning (ML) holds promise for transforming ITP treatment by analysing complex data to identify predictive factors, as demonstrated by Xu et al.'s study which developed ML-based models to predict responses to corticosteroids, rituximab and thrombopoietin receptor agonists. However, these models require external validation before can be adopted in clinical practice. Commentary on: Xu et al. A novel scoring model for predicting efficacy and guiding individualised treatment in immune thrombocytopenia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19615.

Safety and efficacy of SARS-CoV-2 vaccination in patients with immune thrombocytopenia: A two-centre review.

Multiple studies have reported immune thrombocytopenia (ITP) relapse following SARS-CoV-2 vaccination, however baseline ITP relapse rate and antibody response to vaccination are not known. Patients with ITP who received at least one of the first three SARS-CoV-2 vaccination doses were included in the study. One hundred and twenty-four patients met the inclusion criteria. Relapse rate was 4.2% following a first vaccine dose, 9.1% after a second and 2.9% after a third; baseline relapse rate was 7.6%. Ninety-four per cent of patients who received three vaccine doses developed a clinical antibody response. SARS-CoV-2 vaccination appears to be safe and effective in patients with ITP.

Toxicity due to steroid treatment in ITP remains a concern.

Corticosteroids are the preferred first-line treatment in ITP in guidelines. The analyses by Wang et al. shows that hospital-registered steroid-related toxicity occurs frequently and emphasizes that exposure should be for a limited duration of time. Commentary on: Wang et al. Longitudinal evaluation of adverse events due to steroid use in primary immune thrombocytopenia: a population-based study. Br J Haematol 2024;204:1986-1993.

Treatment with fostamatinib in patients with immune thrombocytopenia: Experience from the Andalusian region in Spain-The Fostasur Study.

Immune thrombocytopenia (ITP) is characterized by low platelet counts (PLTs) and an increased risk of bleeding. Fostamatinib, a spleen tyrosine kinase inhibitor, has been approved as a second-line treatment for ITP. Real-world data on fostamatinib are lacking. This observational, retrospective, multicentre study, conducted in the Andalusia region of Spain, evaluated 44 adult primary ITP patients (47.7% female; median age 58 years; newly diagnosed ITP 6.8%; persistent 13.6%; chronic 79.5%; median four prior treatments) after ≥ 4 weeks of fostamatinib therapy. The median PLT at the initiation of fostamatinib was 15 × 109/L. Common reasons for starting fostamatinib were refractoriness or intolerance to prior therapy, oral medication preference, history of thrombosis and cardiovascular risk. Dosing was individualized based on efficacy and tolerance. After 2 weeks, global response rate was 56.8% (response and complete response). Response rates were 70.5%, 62.5% and 64% at 4 weeks, 12 weeks and at the end of the study respectively. Adverse events were mild, and no patients discontinued as a result. This real-world study demonstrated a response rate similar to fostamatinib as seen in the pivotal clinical trials while including newly diagnosed patients and allowing for individualized dosing.

Integrating chemokines and machine learning algorithms for diagnosis and bleeding assessment in primary immune thrombocytopenia: A prospective cohort study.

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder, and chemokines have been shown to be dysregulated in autoimmune disorders. We conducted a prospective analysis to identify potential chemokines that could enhance the diagnostic accuracy and bleeding evaluation in ITP patients. In the discovery cohort, a Luminex-based assay was employed to quantify concentrations of plasma multiple chemokines. These levels were subjected to comparative analysis using a cohort of 60 ITP patients and 17 patients with thrombocytopenia other than ITP (non-ITP). Additionally, comparative evaluation was conducted between a subgroup of 12 ITP patients characterised by bleeding episodes (ITP-B, as defined by an ITP-2016 bleeding grade ≥2) and 33 ITP patients without bleeding episodes (ITP-NB, as defined by an ITP-2016 bleeding grade ≤1). Machine learning algorithms further identified CCL20, interleukin-2, CCL26, CCL25, and CXCL1 as promising indicators for accurate diagnosis of ITP and CCL21, CXCL8, CXCL10, CCL8, CCL3, and CCL15 as biomarkers for assessing bleeding risk in ITP patients. The results were confirmed using enzyme-linked immunosorbent assays in a validation cohort (43 ITP patients and 19 non-ITP patients). Overall, the findings suggest that specific chemokines show promise as potential biomarkers for diagnosis and bleeding evaluation in ITP patients.

Avatrombopag plus fostamatinib combination as treatment in patients with multirefractory immune thrombocytopenia.

Immune thrombocytopenia (ITP) refractory to multiple therapies may require a combination of drugs targeting different mechanisms and targets. In this retrospective, multicentre, international study, we report the safety and effectiveness of avatrombopag and fostamatininb in combination administered to 18 patients with multirefractory ITP. Overall, the combination response was achieved in 15 patients (83.3%), with a median time from combination start to best response of 15 days (IQR: 8-35 days). After a median follow-up of 256 days (IQR: 142.8-319), 5 patients relapsed (26.7%), all during tapering or stopping one drug. Adverse events were described in 6 of 18 patients (33%).

Platelet response to romiplostim amongst patients with newly diagnosed, persistent, and chronic immune thrombocytopenia in routine clinical practice in Denmark, Sweden, and Norway.

Patient characteristics and platelet responses at romiplostim initiation according to the duration of immune thrombocytopenia (ITP) are poorly understood. Amongst romiplostim-exposed adults with ITP lasting ≥6 months during 2009-2018 in Denmark, Sweden, and Norway, we examined characteristics at romiplostim initiation, romiplostim dosage, and durable platelet response (≥75% of measurements ≥50 × 109/L at 14-24 weeks) for subcohorts with newly diagnosed (duration <3 months), persistent (3-12 months), or chronic (>12 months) ITP initiating romiplostim. The 285 romiplostim initiators comprised 81 (28%) with newly diagnosed, 47 (16%) with persistent, and 157 (55%) with chronic ITP. More patients with newly diagnosed ITP than longer ITP duration, had low comorbidity levels, two or more prior ITP therapies, and previous bleeding requiring hospitalisation. The median romiplostim doses were similar across subcohorts. During treatment, median platelet counts were similar across subcohorts (75-76 × 109/L), and the durable platelet response was 64.6%, 52.9%, and 52.7% for newly diagnosed, persistent, and chronic ITP, respectively. After treatment cessation, the median platelet count was 138 × 109/L, 68 × 109/L, and 71 × 109/L, respectively. In conclusion, newly diagnosed patients, compared with romiplostim initiators with longer disease duration, had more severe ITP, higher frequency of durable platelet response, and higher median platelet count after cessation.

B-cell responses to ITP treatments.

Deficiency in regulatory B cells has been suggested in immune thrombocytopenia. In this study, Stimpson et al. emphasize the importance of considering the treatments received for immunological analyses. Commentary on: Stimpson et al. Systemic immunosuppression depletes peripheral blood regulatory B cells in patients with immune thrombocytopenia. Br J Haematol 2024;204:644-648.

Efficacy of thrombopoietin receptor agonists versus rituximab in non-responsive immune thrombocytopenia-A single centre retrospective analysis.

Management of immune thrombocytopenia (ITP) beyond initial glucocorticoid therapy is challenging. In this retrospective single-centre cohort study, we compared all ITP patients relapsed or non-responsive to glucocorticoid therapy treated with either continuous TPO-RAs (n = 35) or rituximab induction (n = 20) between 2015 and 2022. While both groups showed high initial complete response rates (CR, 68.6 vs. 80.0%, ns), the overall rate of progression to the next therapy was higher after time-limited rituximab (75.0 vs. 42.9%), resulting in a lower relapse-free survival (median 16.6 vs. 25.8 months, log-rank; p < 0.05). We conclude that both treatments show similar initial efficacy and their ideal duration of therapy warrants further investigation.

Real-world use of thrombopoietin receptor agonists for the management of immune thrombocytopenia in adult patients in the United Kingdom: Results from the TRAIT study.

Few studies have reported the real-world use of both romiplostim and eltrombopag in immune thrombocytopenia (ITP). TRAIT was a retrospective observational study aimed to evaluate the platelet responses and adverse effects associated with the use of these thrombopoietin receptor agonists (TPO-RAs) in adult patients with ITP in the United Kingdom. Of 267 patients (median age at diagnosis, 48 years) with ITP (primary ITP [n = 218], secondary ITP [n = 49]) included in the study, 112 (42%) received eltrombopag and 155 (58%) received romiplostim as the first prescribed TPO-RA. A platelet count ≥30 × 109/L was achieved in 89% of patients with the first TPO-RA treatments, while 68% achieved a platelet count ≥100 × 109/L. Treatment-free response (TFR; platelet count ≥30 × 109/L, 3 months after discontinuing treatment) was achieved by 18% of the total patients. Overall, 61 patients (23%) switched TPO-RAs, most of whom achieved platelet counts ≥30 × 109/L with the second TPO-RA (23/25 who switched from eltrombopag to romiplostim [92%]; 28/36 who switched from romiplostim to eltrombopag [78%]). TFR was associated with secondary ITP, early TPO-RA initiation after diagnosis, the presence of comorbidity and no prior splenectomy or treatment with steroids or mycophenolate mofetil. Both TPO-RAs had similar efficacy and safety profiles to those reported in clinical studies.

Autoimmune cytopenia and Kabuki syndrome in paediatrics: Insights in 11 patients.

Kabuki syndrome (KS) is now listed in the Human Inborn Errors of Immunity (IEI) Classification. It is a rare disease caused by KMT2D and KDM6A variants, dominated by intellectual disability and characteristic facial features. Recurrently, pathogenic variants are identified in those genes in patients examined for autoimmune cytopenia (AIC), but interpretation remains challenging. This study aims to describe the genetic diagnosis and the clinical management of patients with paediatric-onset AIC and KS. Among 11 patients with AIC and KS, all had chronic immune thrombocytopenic purpura, and seven had Evans syndrome. All had other associated immunopathological manifestations, mainly symptomatic hypogammaglobinaemia. They had a median of 8 (5-10) KS-associated manifestations. Pathogenic variants were detected in KMT2D gene without clustering, during the immunological work-up of AIC in three cases, and the clinical strategy to validate them is emphasized. Eight patients received second-line treatments, mainly rituximab and mycophenolate mofetil. With a median follow-up of 17 (2-31) years, 8/10 alive patients still needed treatment for AIC. First-line paediatricians should be able to recognize and confirm KS in children with ITP or multiple AIC, to provide early appropriate clinical management and specific long-term follow-up. The epigenetic immune dysregulation in KS opens exciting new perspectives.

Cognitive impairment among patients with chronic immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disease typically associated with severely depleted platelet counts. However, additional symptoms (e.g. increased fatigue and memory/concentration difficulties) can profoundly impact patients' quality of life. The nature and severity of cognitive impairment in ITP, and potential association with patient/disease characteristics were evaluated in 49 adults with relapsed/refractory ITP. The Cogstate Brief Battery quantitatively assessed psychomotor function (DET), attention (IDN), visual learning (OCL) and working memory (ONB) individually, as well as DET/IDN and OCL/ONB composites. Clinically important cognitive impairment (defined as z-score ≤ -1) for ≥2 individual tests was observed in 29 patients (59%). Impairment was highest for IDN (67% of patients), followed by DET (53%), ONB (39%) and OCL (16%). A higher magnitude of impairment was observed for the DET/IDN composite (mean z-score -1.54; 95% CI, -1.94 to -1.13) than OCL/ONB (mean z-score -0.21; 95% CI, -0.49 to 0.07). The severity of cognitive impairment was comparable to mild traumatic brain injury and associated with increasing age and fatigue but unrelated to platelet count or corticosteroid use. Overall, these results warrant a clinical need to further consider the potential of cognitive dysfunction in assessing ITP patients.

Lightening the load for paediatric ITP: The importance of health-related quality of life.

In their paper, Klaassen et al. present their findings on the revised Kids ITP Tools (KIT). This important work provides an update to the validated measure for evaluating health-related quality of life (HRQoL) in children with immune thrombocytopenia (ITP). ITP, an acquired autoimmune disorder, results in thrombocytopenia and places children at risk for significant bleeding. Thankfully, the majority of children with ITP will have a brief disease course and no or mild bleeding symptoms. The rarity of severe bleeding events or the development of chronic disease provides a challenge with regard to clinical trial design, making alternative measures of pharmacological efficacy extremely important. Commentary on: Dhir et al. Quality of life in childhood immune thrombocytopenia: Revision of the Kids' ITP Tools (KIT). Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19662.

Differential alterations of CXCR3, CXCR5 and CX3CR1 in patients with immune thrombocytopenia.

As a versatile element for maintaining homeostasis, the chemokine system has been reported to be implicated in the pathogenesis of immune thrombocytopenia (ITP). However, research pertaining to chemokine receptors and related ligands in adult ITP is still limited. The states of several typical chemokine receptors and cognate ligands in the circulation were comparatively assessed through various methodologies. Multiple variable analyses of correlation matrixes were conducted to characterize the correlation signatures of various chemokine receptors or candidate ligands with platelet counts. Our data illustrated a significant decrease in relative CXCR3 expression and elevated plasma levels of CXCL4, 9-11, 13, and CCL3 chemokines in ITP patients with varied platelet counts. Flow cytometry assays revealed eminently diminished CXCR3 levels on T and B lymphocytes and increased CXCR5 on cytotoxic T cell (Tc) subsets in ITP patients with certain platelet counts. Meanwhile, circulating CX3CR1 levels were markedly higher on T cells with a concomitant increase in plasma CX3CL1 level in ITP patients, highlighting the importance of aberrant alterations of the CX3CR1-CX3CL1 axis in ITP pathogenesis. Spearman's correlation analyses revealed a strong positive association of peripheral CXCL4 mRNA level, and negative correlations of plasma CXCL4 concentration and certain chemokine receptors with platelet counts, which might serve as a potential biomarker of platelet destruction in ITP development. Overall, these results indicate that the differential expression patterns and distinct activation states of peripheral chemokine network, and the subsequent expansion of circulating CXCR5+ Tc cells and CX3CR1+ T cells, may be a hallmark during ITP progression, which ultimately contributes to thrombocytopenia in ITP patients.

Obesity is associated with adverse outcomes in primary immune thrombocytopenia - a retrospective single-center study.

The pathophysiology of immune thrombocytopenia (ITP) involves immune-mediated platelet destruction. The presence of adipose tissue in obese individuals creates an inflammatory environment that could potentially impact the clinical course and outcomes of ITP. However the relationship between obesity and ITP outcomes has not been well described. We evaluated ITP outcomes in 275 patients diagnosed with primary ITP from 2012 to 2022. Patients were categorized into four groups based on their body mass index (BMI) at diagnosis. Female gender was associated with a lower platelet count at the time of diagnosis at any BMI. Patients with high BMI had lower platelet counts at diagnosis and at platelet nadir (p < 0.001), an increased likelihood of requiring therapy (p < 0.001) and requiring multiple lines of therapy (p = 0.032). Non-obese patients who required corticosteroid treatment experienced a longer remission duration compared to obese patients (p = 0.009) and were less likely to be steroid-dependent (p = 0.048). Our findings suggest that obesity may be a significant risk factor for developing ITP and for ITP prognosis. Future studies are needed to evaluate the role of weight loss intervention in improving ITP outcomes.

Efficacy and safety of fostamatinib in refractory immune thrombocytopenia: a meta-analysis from randomized controlled trials.

BACKGROUND: Immune thrombocytopenia (ITP) is an immune-mediated disease that results in low platelet counts. Despite appropriate treatment, many patients continue to experience refractory disease. Fostamatinib, an oral spleen tyrosine kinase (SYK) inhibitor, has emerged as a promising option for refractory ITP. OBJECTIVE: This meta-analysis aims to evaluate the efficacy and safety of fostamatinib compared to conventional therapy in adults aged ≥ 18 years with refractory ITP. MATERIALS AND METHODS: Literature search was conducted in PubMed, Scopus, Embase, and clinicaltrials.gov databases from inception to March 31, 2024. Randomized controlled trials (RCTs) assessing the safety and efficacy of fostamatinib in adults with refractory ITP were included. Data extraction, risk of bias assessment, and statistical analysis were performed following PRISMA guideline. RESULTS: A total of 495 articles were screened, with three RCTs meeting the inclusion criteria. Fostamatinib therapy demonstrated superior efficacy in achieving stable platelet response by week 24 (ORR 0.80; 95%CI 0.72-0.88), platelet count ≥ 50,000/µL at weeks 12 (ORR 0.80; 95%CI 0.72-0.90) and week 24 (ORR 0.82; 95%CI 0.72-0.90). Additionally, fostamatinib improves platelet counts in subjects with a baseline count of < 15,000/µL. The Number Needed to Treat (NNT) was calculated as 10. Adverse effects include diarrhea (RR 2.32; 95%CI 1.11-4.84), hypertension (RR 2.33; 95%CI 1.00-5.43), and abnormal liver function tests (RR 4.18; 95% CI 1.00-17.48). Interestingly, the occurrences of nausea (RR 1.77; 95% CI 0.33-9.67) and rash (RR 2.28; 95% CI 0.50-10.29) did not achieve statistical significance. CONCLUSION: This meta-analysis provides robust evidence supporting the efficacy of fostamatinib in improving platelet counts and achieving therapeutic goals in adults with refractory ITP. However, fostamatinib's safety profile warrants consideration due to higher rates of diarrhea, hypertension, and abnormal liver function tests.

SARS-CoV-2 infection-induced immune thrombocytopenia: a systematic review of current reports.

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count with increased risk of bleeding, and viral infection may trigger ITP. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-induced ITP has been increasingly reported. We systemically reviewed the previously reported cases of SARS-CoV-2 infection-induced ITP and identified a total of 105 patients from 68 studies. The median age was 61 years, and 14 patients (12%) were < 18 years old (pediatric cases). In adult cases, a total of 53% patients were classified as moderate to severe SARS-CoV-2 infection. The median platelet count at diagnosis and nadir were 6,000/µL and 4,000/µL, respectively. When comparing platelet levels between non-severe SARS-CoV-2 infection and moderate to severe SARS-CoV-2 infection, the median values of platelet levels at diagnosis were not significantly different between the groups (4,000/µL in non-severe SARS-CoV-2 infection and 9,000/µL in moderate to severe SARS-CoV-2 infection, p-value = 0.22). Median nadir platelet levels were also not significantly different between groups (4,000/µL in non-severe SARS-CoV-2 infection and 8,000/µL in moderate to severe SARS-CoV-2 infection, p-value = 0.27). More than half of the cases (53 patients) were treated with combination therapy including steroid, intravenous immunoglobulin, and eltrombopag. Major bleeding and intracranial hemorrhage occurred in ten (11%) and six (6.6%) cases, respectively. The overall mortality rate was 7%. In pediatric cases, none of the patients experienced major bleeding and lethal outcomes.

Flow cytometry for comprehensive assessment of platelet functional activity in response to ADP stimulation.

OBJECTIVES: Flow cytometry with adenosine diphosphate (ADP) allows to characterize molecular changes of platelet function caused by this physiologically important activation, but the methodology has not been thoroughly investigated, standardized and characterized yet. We analyzed the influence of several major variables and chose optimal conditions for platelet function assessment. METHODS: For activation, 2.5 µM CaCl2 , 5 µM ADP and antibodies were added to diluted blood and incubated for 15 min. We analyzed kinetics of antibody binding and effects of their addition sequence, agonist concentration, blood dilution, exogenous calcium addition and platelet fixation. RESULTS: We tested our protocol on 11 healthy children, 22 healthy adult volunteers, 9 patients after a month on dual antiplatelet therapy after percutaneous coronary intervention (PCI), 7 adult patients and 14 children with immune thrombocytopenia (ITP). We found that our protocol is highly sensitive to ADP stimulation with low percentage of aggregates formation. The assay is also sensitive to platelet function inhibition in post-PCI patients. Finally, platelet preactivation with ITP plasma was stronger and caused increase in activation response to ADP stimulation compared to preactivation with low dose of ADP. CONCLUSIONS: Our assay is sensitive to antiplatelet therapy and platelet preactivation in ITP patients under physiological conditions with minimal percentage of aggregates formation.