Characteristics and outcomes of COVID-19 in Chinese immune thrombocytopenia patients: A prospective cohort study.

The coronavirus disease 2019 (COVID-19) pandemic has a significant impact on the immune system. This is the first and largest study on pre-existing immune thrombocytopenia (ITP) patients infected with COVID-19 in China. We prospectively collected ITP patients infected with COVID-19 enrolled in the National Longitudinal Cohort of Hematological Diseases (NICHE, NCT04645199) and followed up for at least 1 month after infection. One thousand and one hundred forty-eight pre-existing ITP patients were included. Two hundred and twelve (18.5%) patients showed a decrease in the platelet (PLT) count after infection. Forty-seven (4.1%) patients were diagnosed with pneumonia. Risk factors for a decrease in the PLT count included baseline PLT count <50 × 109/L (OR, 1.76; 95% CI, 1.25-2.46; p = 0.001), maintenance therapy including thrombopoietin receptor agonists (TPO-RAs) (OR, 2.27; 95% CI, 1.60-3.21; p < 0.001) and previous splenectomy (OR, 1.98; 95% CI, 1.09-3.61; p = 0.03). Risk factors for pneumonia included age ≥40 years (OR, 2.45; 95% CI, 1.12-5.33; p = 0.02), ≥2 comorbidities (OR, 3.47; 95% CI, 1.63-7.64; p = 0.001), maintenance therapy including TPO-RAs (OR, 2.14; 95% CI, 1.17-3.91; p = 0.01) and immunosuppressants (OR, 3.05; 95% CI, 1.17-7.91; p = 0.02). In this cohort study, we described the characteristics of pre-existing ITP patients infected with COVID-19 and identified several factors associated with poor outcomes.

Protective effects of COVID-19 vaccination in splenectomized patients with immune thrombocytopenia.

Splenectomy is an effective treatment for immune thrombocytopenia (ITP). The effect of COVID-19 vaccination on splenectomized patients with ITP during the COVID-19 pandemic has not been reported. Therefore, this study aimed to investigate the effect of COVID-19 vaccination on clinical outcomes in these patients. This was a longitudinal study of splenectomized patients with ITP. A total of 191 splenectomized patients were included in this study. After a median follow-up of 114 months, 146 (76.4%) patients had a sustained response to splenectomy. During COVID-19 infection, vaccinated patients showed a lower risk of severe infections (odds ratio [OR], 0.13; 95% confidence interval [CI]: 0.05-0.36; p < 0.001), hospitalization (OR, 0.13; 95% CI, 0.04-0.48; p = 0.002), and ITP exacerbation (OR, 0.16; 95% CI, 0.04-0.67; p = 0.012). These findings indicate that COVID-19 vaccination plays a protective role in splenectomized patients with ITP.

Increased risk of haematological malignancy in adults over age 60 with thrombocytopenia compared with matched controls: Time for an upfront bone marrow evaluation?

International societies have conflicting recommendations on whether bone marrow aspirate/biopsy (BMB) is needed during workup for isolated thrombocytopenia. Our objective was to determine if thrombocytopenia in patients aged ≥60 years is associated with an increased incidence of haematological malignancy. We performed a retrospective population-based cohort study in patients aged ≥60 years between January 1, 2009 to December 31, 2019. Exposed patients had specialist consultation for thrombocytopenia, with platelet count <100 × 109/L, but normal haemoglobin and white blood cell count. Unexposed patients were those who never had specialist consultation for thrombocytopenia and whose platelets were ≥100 × 109/L. The primary outcome was the diagnosis of haematological malignancy using a competing risk of death model. During 4.0 years (IQR 2.2-6.7) of follow-up, 378/4930 exposed (19.1/1000PY, 95% CI 17.1-21.0), and 204/17556 unexposed patients (2.5/1000PY, 95% CI 2.2-2.8) were diagnosed with haematological malignancy (HR 15.5 (95% CI 11.3-21.4, p < 0.0001) in year 1, and 5.3 (95% CI 4.4-6.6, p < 0.0001) in years 2+). This finding persisted in analyses stratified by sex, age, severity, or duration of thrombocytopenia, and treatment with corticosteroids within 2 weeks of consultation. This study found a strong association between isolated thrombocytopenia and haematological malignancy in patients ≥60 years, supporting consideration of diagnostic testing including BMB during outpatient specialist consultation.

Longitudinal evaluation of adverse events due to steroid use in primary immune thrombocytopenia: A population-based study.

This study aimed to investigate the association between the steroid use patterns and the risk of AEs in patients with primary immune thrombocytopenia (ITP). A total of 2691 newly diagnosed adults with ITP between 2011 and 2018 were identified from the National Health Insurance Research Database in Taiwan, and the date of first steroid use was defined as the index date. Post-index steroid use was calculated on a 90-day basis as a time-dependent variable and categorized by the average prednisolone-equivalent daily dose (<10 mg vs. ≥10 mg) and intensity (medication possession ratio <80% vs. ≥80%). Patients were followed up for 1 year from the index date for acute AE events, while chronic AEs were assessed until death, or end of 2019. Compared to patients with low-dose+low-intensity steroid use, those with high-dose+high-intensity steroid use were associated with a higher risk of acute AE (adjusted incident rate ratio [aIRR]: 1.57, 95% confidence interval [CI]: 1.38-1.78, p < 0.01) and chronic AE (aIRR: 1.26, 95% CI: 1.08-1.47, p < 0.01). Metabolic/endocrine and ophthalmologic disorders demonstrated the strongest correlation with a high dose and intensity. The joint effect of steroid dose and intensity was observed in patients with ITP, and the findings suggest that steroids should be used carefully.

Comparison of platelet transfusion effectiveness between Helicobacter pylori-positive and -negative immune thrombocytopenia.

Immune thrombocytopenia (ITP) is characterized by early platelet destruction and impaired platelet production. Helicobacter pylori (H. pylori) infection seems to contribute to the pathogenesis in certain ITP patients in Japan. We compared the effectiveness of platelet transfusion in severe ITP in the presence or absence of H. pylori. The median corrected count increment (CCI) at 24 h after platelet transfusion (CCI-24) of the H. pylori-positive ITP patients was higher than that of the H. pylori-negative ITP patients (6463 vs. 754, p < 0.001), and the CCI-1 was also in the same direction but not significant (23 351 vs. 11 578). Multiple regression analyses showed that H. pylori infection was independently associated with CCI-24. Our study suggests that platelet transfusion may be more effective in H. pylori-positive ITP patients.

Efficacy and safety of avatrombopag in Chinese children with persistent and chronic primary immune thrombocytopenia: A multicentre observational retrospective study in China.

Avatrombopag (AVA) is a novel thrombopoietin receptor agonist (TPO-RA) that has been recently approved as a second-line therapy for immune thrombocytopenia (ITP) in adults; however, its safety and efficacy data in children are lacking. Here, we demonstrated the efficacy and safety of AVA as second-line therapy in children with ITP. A multicentre, retrospective, observational study was conducted in children with persistent or chronic ITP who did not respond to or relapsed from previous treatment and were treated with AVA for at least 12 weeks between August 2020 and December 2022. The outcomes were the responses (defined as achieving a platelet count ≥30 × 109/L, twofold increase in platelet count from baseline and absence of bleeding), including rapid response within 4 weeks, sustained response at weeks 12 and 24, bleeding control and adverse events (AEs). Thirty-four (18 males) patients with a mean age of 6.3 (range: 1.9-15.3) years were enrolled. The median number of previous treatment types was four (range: 1-6), and 41.2% patients switched from other TPO-RAs. Within 4 weeks, overall response (OR) was achieved in 79.4% patients and complete response (CR, defined as a platelet count ≥100 × 109/L and the absence of bleeding) in 67.7% patients with a median response time of 7 (range: 1-27) days. At 12 weeks, OR was achieved in 88.2%, CR in 76.5% and sustained response in 44% of patients. At 24 weeks, 22/34 (64.7%) patients who achieved a response and were followed up for 24 weeks were evaluated; 12/22 (54.55%) achieved a sustained response. During AVA therapy, median platelet counts increased by week 1 and were maintained throughout the treatment period. The proportion of patients with grade 1-3 bleeding decreased from 52.95% at baseline to 2.94% at 12 weeks, while concomitant ITP medications decreased from 36.47% at baseline to 8.82% at 12 weeks, with only 9 (26.47%) patients receiving rescue therapy 23 times within 12 weeks. There were 61.8% patients with 59 AEs: 29.8% with Common Terminology Criteria for Adverse Events grade 1 and the rest with grade 2. These findings show that AVA could achieve a rapid and sustained response in children with persistent or chronic ITP as a second-line treatment, with good clinical bleeding control and reduction of concomitant ITP therapy, without significant AEs.

Improving the chances of response to splenectomy in immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by isolated thrombocytopenia. Its pathogenesis is complex relying in large part on destruction of platelets recognized by autoantibodies within the spleen. However, other mechanisms, such as platelet desialylation, may play a role in platelet reduction by accelerating their clearance in the liver. In their study, Mendoza and colleagues reported on platelet scintigraphy performed in 51 ITP patients, showing a response in 87.5% when the sequestration occurred in the spleen versus 45% in case of non-splenic destruction. Platelet desialylation was also measured after splenectomy and found to be higher in non-responder patients. These latter results, while requiring confirmation prior to splenectomy, support platelet desialylation may also be a potential biomarker of non-response to splenectomy. Commentary on: Mendoza et al. Study of platelet kinetics in immune thrombocytopenia to predict splenectomy response. Br J Haematol 2024;204:315-323.

Study of platelet kinetics in immune thrombocytopenia to predict splenectomy response.

Despite the efficacy of splenectomy for chronic immune thrombocytopenia (ITP), its considerable failure rate and its possible related complications prove the need for further research into potential predictors of response. The platelet sequestration site determined by 111 In-labelled autologous platelet scintigraphy has been proposed to predict splenectomy outcome, but without standardisation in clinical practice. Here, we conducted a single-centre study by analysing a cohort of splenectomised patients with ITP in whom 111 In-scintigraphy was performed at La Paz University Hospital in Madrid to evaluate the predictive value of the platelet kinetic studies. We also studied other factors that could impact the splenectomy outcome, such as patient and platelet characteristics. A total of 51 patients were splenectomised, and 82.3% responded. The splenic sequestration pattern predicted a higher rate of complete response up to 12 months after splenectomy (p = 0.005), with 90% sensitivity and 77% specificity. Neither age, comorbidities, therapy lines nor previous response to them showed any association with response. Results from the platelet characteristics analysis revealed a significant loss of sialic acid in platelets from the non-responding patients compared with those who maintained a response (p = 0.0017). Our findings highlight the value of splenic sequestration as an independent predictor of splenectomy response.

Comprehensive analysis and prediction model of mitophagy and ferroptosis in primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is linked to specific pathogenic mechanisms, yet its relationship with mitophagy and ferroptosis is poorly understood. This study aimed to identify new biomarkers and explore the role of mitophagy and ferroptosis in ITP pathogenesis. Techniques such as differential analysis, Mfuzz expression pattern clustering, machine learning, gene set enrichment analysis, single-cell RNA sequencing (scRNA-seq) and immune infiltration analysis were employed to investigate the molecular pathways of pivotal genes. Two-sample Mendelian randomization (TSMR) assessed the causal effects in ITP. Key genes identified in the training set included GABARAPL1, S100A8, LIN28A, and GDF9, which demonstrated diagnostic potential in validation sets. Functional analysis indicated these genes' involvement in ubiquitin phosphorylation, PPAR signalling pathway and T-cell differentiation. Immune infiltration analysis revealed increased macrophage presence in ITP, related to the critical genes. scRNA-seq indicated reduced GABARAPL1 expression in ITP bone marrow macrophages. TSMR linked S100A8 with ITP diagnosis, presenting an OR of 0.856 (95% CI = 0.736-0.997, p = 0.045). The study pinpointed four central genes, GABARAPL1, S100A8, LIN28A, and GDF9, tied to mitophagy and ferroptosis in ITP. It posits that diminished GABARAPL1 expression may disrupts ubiquitin phosphorylation and PPAR signalling, impairing mitophagy and inhibiting ferroptosis, leading to immune imbalance.

New findings and new methods on macrophages in primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease with multiple immune cells take part in the pathogenesis. Macrophages play multiple roles in both innate and adaptive immune system. The report by Jiani Mo and colleagues identified new biomarkers and explore the role of mitophagy and ferroptosis in ITP pathogenesis. Commentary on: Mo et al. Comprehensive analysis and prediction model of mitophagy and ferroptosis in primary immune thrombocytopenia. Br J Haematol 2024;204:2429-2442.

Broadening the horizon of immune thrombocytopenia through Omics approaches.

Immune thrombocytopenia (ITP) is a highly heterogeneous autoimmune bleeding disorder characterized by low platelet counts due to an immune-mediated platelet destruction and impaired platelet production. The pathophysiology is multifactorial and remains to be fully unravelled. Consequently, disease trajectories and responses to therapeutics, despite the availability of multiple agents, can be unpredictable and differing between patients. There is an urgent need for the identification of diagnostic and therapeutic biomarkers, but this has proven to be challenging to achieve. To shed light on this, two studies in this issue of the British Journal of Haematology have recognized the opportunity of using high-throughput Omics technologies in ITP. Sun et al. performed proteomics, and Li et al. metabolomics, on bone marrow biopsy samples of patients with ITP. This was conducted using mass spectrometry and, due to the generation of large datasets, in combination with machine learning. These studies set the stage for further investigations exploring the high potential of multi-omics technologies in order to shed light on the heterogeneity in ITP, accelerating the path towards a much needed personalized medicine approach. Commentary on: Li et al. Metabolomics profile and machine learning prediction of treatment responses in immune thrombocytopenia: A prospective cohort study. Br J Haematol 2024;204:2405-2417. Commentary on: Sun et al. Proteomics landscape and machine learning prediction of long-term response to splenectomy in primary immune thrombocytopenia. Br J Haematol 2024;204:2418-2428.

The early and rapid response to daratumumab in children with chronic refractory immune thrombocytopenia from a referral single centre of China.

Chronic refractory primary immune thrombocytopenia (CRITP) is currently defined as refractory to multiple therapeutic of second-line agents with or without splenectomy, faced with the threat of severe bleeding and challenging to obtain effective treatment. Although stable and effective drug therapy is needed, it is tough to find one. Daratumumab (Dara), an anti-CD38 monoclonal antibody presented the target cloned plasma cells in multiple myeloma, has also been reported to be effective in refractory autoimmune cytopenia in some case or series reports and ongoing clinical trials for adult patients with CRITP. Here, we report the early and durable response of Dara combination with avatrombopag in three CRITP patients (2 male and 1 female aged 12, 5 and 7 years, respectively) in our centre, with a follow-up period of more than 25 weeks. Before Dara, the duration of immune thrombocytopenia was 9, 1.4 and 4 years, respectively, a baseline platelet count of 4, 6, 9 × 109/L, the bleeding score was all above level 2 and the number of previous drugs was >3. The time to response (R: Plt ≥30 × 109/L with at least a twofold increase in the baseline count) of Dara was on Day 45, 6 and 4 and achieved complete response (CR: Plt ≥100 × 109/L) on Day 51, 6 and 8, the sustained response (SR: Plt >30 × 109/L following Dara at ≥75% of the platelet count assessment at follow-up end-point since the patient achieved response) was 48, 175 and 204 days with the follow-up time of 39.1, 25.9 and 29.7 weeks. The bleeding score decreased from grade 3 to grade 0 during follow-up. No significant treatment-related adverse events were found during follow-up. Dara combination with avatrombopag may be a safe and efficacious therapy for children with CRITP, but it needs to be further explored.

Metabolomics profile and machine learning prediction of treatment responses in immune thrombocytopenia: A prospective cohort study.

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by antibody-mediated platelet destruction and impaired platelet production. The mechanisms underlying ITP and biomarkers predicting the response of drug treatments are elusive. We performed a metabolomic profiling of bone marrow biopsy samples collected from ITP patients admission in a prospective study of the National Longitudinal Cohort of Hematological Diseases. Machine learning algorithms were conducted to discover novel biomarkers to predict ITP patient treatment responses. From the bone marrow biopsies of 91 ITP patients, we quantified a total of 4494 metabolites, including 1456 metabolites in the positive mode and 3038 metabolites in the negative mode. Metabolic patterns varied significantly between groups of newly diagnosed and chronic ITP, with a total of 876 differential metabolites involved in 181 unique metabolic pathways. Enrichment factors and p-values revealed the top metabolically enriched pathways to be sphingolipid metabolism, the sphingolipid signalling pathway, ubiquinone and other terpenoid-quinone biosynthesis, thiamine metabolism, tryptophan metabolism and cofactors biosynthesis, the phospholipase D signalling pathway and the phosphatidylinositol signalling system. Based on patient responses to five treatment options, we screened several metabolites using the Boruta algorithm and ranked their importance using the random forest algorithm. Lipids and their metabolism, including long-chain fatty acids, oxidized lipids, glycerophospholipids, phosphatidylcholine and phosphatidylethanolamine biosynthesis, helped differentiate drug treatment responses. In conclusion, this study revealed metabolic alterations associated with ITP in bone marrow supernatants and a potential biomarker predicting the response to ITP.

Proteomics landscape and machine learning prediction of long-term response to splenectomy in primary immune thrombocytopenia.

This study aimed to identify key proteomic analytes correlated with response to splenectomy in primary immune thrombocytopenia (ITP). Thirty-four patients were retrospectively collected in the training cohort and 26 were prospectively enrolled as validation cohort. Bone marrow biopsy samples of all participants were collected prior to the splenectomy. A total of 12 modules of proteins were identified by weighted gene co-expression network analysis (WGCNA) method in the developed cohort. The tan module positively correlated with megakaryocyte counts before splenectomy (r = 0.38, p = 0.027), and time to peak platelet level after splenectomy (r = 0.47, p = 0.005). The blue module significantly correlated with response to splenectomy (r = 0.37, p = 0.0031). KEGG pathways analysis found that the PI3K-Akt signalling pathway was predominantly enriched in the tan module, while ribosomal and spliceosome pathways were enriched in the blue module. Machine learning algorithm identified the optimal combination of biomarkers from the blue module in the training cohort, and importantly, cofilin-1 (CFL1) was independently confirmed in the validation cohort. The C-index of CFL1 was >0.7 in both cohorts. Our results highlight the use of bone marrow proteomics analysis for deriving key analytes that predict the response to splenectomy, warranting further exploration of plasma proteomics in this patient population.

The use of splenic embolization in immune thrombocytopenia: A systematic review and meta-analysis.

The effectiveness of splenic embolization (SE) in treating refractory immune thrombocytopenia (ITP) remains uncertain. A systematic literature review was undertaken to assess the effectiveness and safety of SE in treating both paediatric and adult patients with ITP. We conducted an extensive search employing predefined criteria. We extracted platelet counts at baseline and at multiple intervals following SE, along with details of the proportion of embolized spleen parenchyma and the proportion of patients exhibiting complete or partial platelet count responses. We identified nine eligible reports for the analysis of effectiveness (228 patients) and 15 reports for the safety analysis (151 patients). Pooled estimates of complete response (platelet count >100 × 109/L) and overall response (platelet count >30 × 109/L) were 50.1% (95% CI: 38-62.3) and 74.4% (95% CI: 64.9-83.9) respectively. Most studies applied an embolization of at least 60% of the spleen parenchyma. Nearly all the patients suffered from mild adverse events (AEs), 1.3% suffered from serious AEs and one patient died (0.7%). In conclusion, SE resulted in an overall response rate in 74.4% of patients with ITP. However, this finding derives from uncontrolled studies of low to moderate quality.

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.

Quality of life in childhood immune thrombocytopenia: Revision of the Kids' ITP Tools (KIT).

The Kids ITP Tools (KIT) is a health-related quality of life (HRQoL) questionnaire that evaluates quality of life in children with immune thrombocytopenia (ITP). There are three formats: Child Self-Report, Parent Proxy-Report and Parent Impact-Report. This study aimed to develop a domain structure by grouping-related questions from the questionnaire into domains that independently reflect various aspects of HRQoL. The study was conducted in two phases. Phase 1 involved an online survey distributed to experts to identify conceptual domains for the KIT. Phase 2 utilized a statistical approach to analyse responses from patients with ITP and their families. A revised KIT 2.0 was ultimately developed to aid in treatment decision-making and monitoring of ITP.

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.

Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France registry.

The aim of this study was to assess the prevalence and the burden of difficult-to-treat primary ITP (pITP), defined by the need for another ITP treatment after romiplostim and eltrombopag. Adult patients were selected in the prospective, real-world CARMEN-France registry up to December 2021. Out of 821 adult patients with pITP, 29 had difficult-to-treat ITP (3.5%; 95% confidence interval [CI]: 2.3%-4.8% in total; 7.6%; 95% CI: 4.9%-10.2% of patients needing ≥2nd line treatment). The 3-year cumulative incidence of bleeding, infection and thrombosis was 100%, 24.1% and 13.8% respectively. The median cumulative duration of hospital stays was 31 days (median follow-up: 30.3 months).

The problem of immune thrombocytopenia refractory to both eltrombopag and romiplostim.

Immune thrombocytopenia refractory to multiple thrombopoietin receptor agonists remains a challenging clinical problem. This commentary discusses and contextualizes the recent report on this entity from Moulis and colleagues, and how to move forward with these patients. Commentary on: Moulis et al. Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France Registry. Br J Haematol 2024;204:1476-1482.