Risk Of Immune Thrombocytopenia Research Articles

Effectiveness and safety of eltrombopag in connective tissue disease patients with refractory immune thrombocytopenia: a retrospective study.

We aimed to investigate the safety and effectiveness of eltrombopag for adult patients with refractory immune thrombocytopenia (ITP) secondary to connective tissue disease (CTD). This is a single-centre, retrospective cohort and propensity score-matched study. Data from CTD-ITP patients treated with eltrombopag between January 2019 and January 2023 were retrospectively analysed. Baseline characteristics and follow-up information were recorded. CTD patients without ITP were matched to identify the risk factors associated with CTD-ITP performed by Logistic regression analysis. Twenty patients were enrolled, including 5 systemic lupus erythematosus (SLE), 9 Sjögren's syndrome (SS) and 6 undifferentiated connective tissue disease (UCTD). Nineteen (95%) patients were female, and the median age was 59 years. Logistic regression analysis showed that anaemia (OR = 8.832, P = 0.007) was associated with increased risk of ITP, while non-erosive arthritis (OR = 0.045, P = 0.001) and interstitial lung disease (OR = 0.075, P = 0.031) were associated with reduced risk. Fourteen patients (70%) achieved a complete response (CR) and one (5%) achieved a partial response (PR). The median response time was 14 days. The median platelet count was 8.5 × 109/l at baseline of eltrombopag and increased to 122 × 109/l after 4 weeks. No adverse events were observed. Eltrombopag appears to be effective, safe and well-tolerated in refractory ITP patients with CTD; larger studies are needed to confirm the generalizability of these findings.

Current Understanding of Immune Thrombocytopenia: A Review of Pathogenesis and Treatment Options.

The management of immune thrombocytopenia (ITP) and the prediction of patient response to therapy still represent a significant and constant challenge in hematology. ITP is a heterogeneous disease with an unpredictable evolution. Although the pathogenesis of ITP is currently better known and its etiology has been extensively studied, up to 75% of adult patients with ITP may develop chronicity, which represents a significant burden on patients' quality of life. A major risk of ITP is bleeding, but knowledge on the exact relationship between the degree of thrombocytopenia and bleeding symptoms, especially at a lower platelet count, is lacking. The actual management of ITP is based on immune suppression (corticosteroids and intravenous immunoglobulins), or the use of thrombopoietin receptor agonists (TPO-RAs), rituximab, or spleen tyrosine kinase (Syk) inhibitors. A better understanding of the underlying pathology has facilitated the development of a number of new targeted therapies (Bruton's tyrosine kinase inhibitors, neonatal Fc receptors, strategies targeting B and plasma cells, strategies targeting T cells, complement inhibitors, and newer TPO-RAs for improving megakaryopoiesis), which seem to be highly effective and well tolerated and result in a significant improvement in patients' quality of life. The disadvantage is that there is a lack of knowledge of the predictive factors of response to treatments, which would help in the development of an optimized treatment algorithm for selected patients.

Lipoprotein lipids and apolipoproteins in primary immune thrombocytopenia: Results from a clinical characteristics and causal relationship verification, potential drug target identification by Mendelian randomization analyses.

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease. Cellular and systemic lipid metabolism plays a significant role in the regulation of immune cell activities. However, the role of lipoprotein lipids and apolipoproteins in ITP remains elusive. The automatic biochemistry analyser was used to measure the levels of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (apoA-I), apoB, apoE and lipoprotein a [LP(a)]. Genetic variants strongly associated with circulating lipoprotein lipids and apolipoproteins (LDL-C, apoB, TG, HDL-C and apoA-I) were extracted to perform Mendelian randomization (MR) analyses. Finally, drug-target MR and passive ITP mice model was used to investigate the potential druggable targets of ITP. Levels of HDL-C, apoA-I, decreased and LP(a) increased in ITP patients compared with healthy controls. Low HDL-C was causally associated with ITP susceptibility. Through drug-target MR and animal modelling, ABCA1 was identified as a potential target to design drugs for ITP. Our study found that lipid metabolism is related to ITP. The causative association between HDL-C and the risk of ITP was also established. The study provided new evidence of the aetiology of ITP. ABCA1 might be a potential drug target for ITP.

Predictors of Immune Thrombocytopenic Purpura in COVID-19 Positive Elderly Admitted in the Pre-Vaccination Era of the Pandemic; An Analysis Via the 2020 National Inpatient Sample

Introduction: Immune thrombocytopenia (ITP) involves an autoimmune destruction of platelets secondary to factors such as lupus erythematosus or viral conditions, e.g., COVID-19. With the onset of the pandemic in 2020, several reports of ITP in COVID-19 patients were published. However, to date, very limited information exists on the factors influencing the odds of ITP among the elderly who were COVID-19-positive before the introduction of mass vaccination campaigns. Hereby, we seek to bridge the knowledge gap via an in-depth analysis of hospitalization records. Methods: Our retrospective analysis via the 2020 National Inpatient Sample included admissions of patients ages≥60 years with a primary diagnosis of COVID-19. As the COVID-19 vaccination began on a large scale in December 2020 in the US and the ICD-10 code ‘U071‘ was introduced in April, we restricted our sample to admissions between April to November 2020 for better accuracy of results. Logistic regression models were used to estimate various patient characteristics that affected the odds of a diagnosis of ITP. Results: Between 1st April 2020 and 30th November 2020, there were 507860 patients of 60 and more years hospitalized primarily for COVID-19. An estimated 830 cases developed ITP, with an incidence rate of 163 cases per 100,000 COVID-19-positive patients. Multiple comorbidities such as a history of autoimmune conditions (aOR 1.982, 95% CI 1.483-2.648, p<0.01), chronic kidney disease (aOR 1.652, 95% CI 1.375-1.984, p<0.01), and cirrhosis (aOR 4.119, 95% CI 2.964-5.724, p<0.01) showed higher odds of ITP. Racial disparities were also noted as compared to Whites, Blacks (aOR 0.523, 95% CI 0.417-0.657, p<0.01) and Hispanics (aOR 0.461, 95% CI 0.355-0.600, p<0.01) showed reduced odds. Furthermore, Medicaid insurers also had lower odds (aOR 0.411, 95% CI 0.244-0.694, p<0.01) than those insured by Medicare. Hypertension (aOR 0.747, 95% CI 0.624-0.894, p<0.01) and long-term aspirin use(aOR 0.700, 95% CI 0.572-0.856, p<0.01) also showed fewer events of ITP (Table 1, Figure 1). The mean Charlson Comorbidity Index (CCI) score was higher among those who had ITP (mean score of 4.20 vs. 3.08, p<0.01). Furthermore, patients with ITP also experienced a longer stay (12.29 days vs. 8.34 days, p<0.01). Events of ITP among the elderly with COVID-19 were linked with a poorer prognosis as 27.1% of all patients died (vs. 15.2% in the non-ITP group, aOR mortality 1.880, 95% CI 1.585-2.230, p<0.01). Conclusion: Our results provide the first report of factors linked with the risk of ITP among the elderly with COVID-19. Various conditions such as autoimmunity and racial disparities have previously been reported to influence events of ITP, as also seen in our study. We further report higher odds among patients with cirrhosis and chronic kidney disease, while those with hypertension and long term aspirin use had lower odds. ITP also led to a higher mortality rate. Broader studies can help understand the impact of our findings during the pre-vaccination era, which can help set a template for protocols among the elderly in future pandemics.

Genetic Variants in Canonical Wnt Signaling Pathway Associated with Pediatric ITP

Introduction : Pediatric immune thrombocytopenia (ITP) is thought to develop when a triggering event inappropriately activates an autoimmune anti-platelet response in the context of predisposing genetic factors. Inborn errors of immunity are increasingly being identified in cases of chronic, refractory autoimmune cytopenias. We sought to identify genetic variants associated with predisposition to 1) primary or secondary pediatric ITP of any disease duration versus healthy controls and 2) chronic ITP (cITP) versus disease that spontaneously resolves in < 1 year (sr-ITP). Methods : DNA and clinical data were derived from 8 sites from the Pediatric ITP Consortium of North America's (ICON) biorepository. Samples were genotyped using the Illumina Global Screening Array BeadChip. Genotypes were imputed using the Michigan Imputation Server HRC reference panel. Genetic variants that passed standard quality metrics and had a MAF ≥1% were retained. Control samples (n=8,372) were obtained from the National Longitudinal Study of Adolescent to Adult Health (Add Health) cohort. Logistic regression models were used to estimate adjusted odds ratios (aORs) comparing (1) ITP and control cohorts and (2) cITP and sr-ITP cohorts. Models assumed additive allelic effects and accounted for the top 3 principal components. Genome-wide significance was defined as P <5 × 10 -8 and suggestive of genome-wide significance, P <1 x 10 -5. Results : Six-hundred ten unique patient samples were genotyped. Nineteen (3.1%) did not pass quality control, leaving 591 for analysis. This cohort included 307 (52.0%) cITP patients, 209 (35.4%) sr-ITP patients, and 75 (12.7%) individuals without complete follow-up data to allow for classification of cITP or sr-ITP. The ITP cohort was 50.1% male, 50.1% non-Hispanic (NH) white, 29.4% Hispanic, 6.1% NH Black, 3.1% NH Asian, and 11.3% Other/Unknown. Compared with healthy controls, we identified 6 loci associated with ITP at genome-wide significance (Figure 1). Located within the intronic region of SLC24A4 rs75650997 was associated with an increased risk of ITP compared with controls (aOR: 2.38, P=3.9x10 -8). An intronic variant, rs2165798, in NAV2 was inversely associated with ITP (aOR: 0.52, P=3.2x10 -11). A variant in NKD1 rs4785216, was inversely associated with ITP (aOR: 0.43, P=8.86x10 -15).Another intergenic variant, rs4785426, in close proximity to NKD1 was also inversely associated with ITP (aOR: 0.48, P=1.84x10 -16) . An additional 20 variants met suggestive of genome-wide significance. When comparing sr-ITP and cITP patients, no SNVs (single nucleotide variant) reached genome-wide significance, but one variant, rs117609649, in ABCC4 met suggestive of genome-wide significance (aOR: 0.26, P=4.49x10 -7). Discussion : This is the largest, unbiased genetic study of pediatric ITP patients. The analysis comparing ITP versus healthy controls identified 20 suggestive SNVs and 6 which met genome-wide significance. Several of the top SNVs identified in this study affect Wnt/β-catenin signaling. Wnt-signaling impacts the development and regulation of immune cell populations including dendritic cells, macrophages, NK cells, B cells, and T cells. NAV2 activates Wnt/β-catenin signaling. NAV2 variants have been implicated in autoimmune conditions including Celiac disease and rheumatoid arthritis. NKD1 inhibits the canonical Wnt/β-catenin signaling pathway. The cumulative impact of these variants on Wnt activity in ITP should be evaluated in the future. No genetic variants met genome-wide significance in a comparison of sr-ITP and cITP patients. Collectively, these findings suggest there may be genetic variants implicated in ITP risk, but those genetic features are not specific to sr-ITP or cITP. A focused analysis of 632 genes that cause inborn errors of immunity (IEI) is ongoing. This includes gene burden testing and analysis of pathogenic variants within this gene subset. Variants in IEI genes will also be evaluated in a sub-population of patients with Evans syndrome. Conclusion : ITP is highly heterogenous in its presentation, disease course, and response to therapy. Mirroring its clinical behavior, the genetic contribution to ITP development is complex. This study identified potential SNVs associated with ITP, but not specific to sr-ITP or cITP. Variants in genes that affect the canonical Wnt-signaling pathway may play a role in ITP risk.

Causal relationship between gut microbiota and immune thrombocytopenia: a Mendelian randomization study of two samples.

Some observational studies have shown that immune thrombocytopenia (ITP) is highly associated with the alteration-composition of gut microbiota. However, the causality of gut microbiota on ITP has not yet been determined. Based on accessible summary statistics of the genome-wide union, the latent connection between ITP and gut microbiota was estimated using bi-directional Mendelian randomization (MR) and multivariable MR (MVMR) analyses. Inverse variance weighted (IVW), weighted median analyses, and MR-Egger regression methods were performed to examine the causal correlation between ITP and the gut microbiota. Several sensitivity analyses verified the MR results. The strength of causal relationships was evaluated using the MR-Steiger test. MVMR analysis was undertaken to test the independent causal effect. MR analyses of reverse direction were made to exclude the potential of reverse correlations. Finally, GO enrichment analyses were carried out to explore the biological functions. After FDR adjustment, two microbial taxa were identified to be causally associated with ITP (PFDR < 0.10), namely Alcaligenaceae (PFDR = 7.31 × 10-2) and Methanobacteriaceae (PFDR = 7.31 × 10-2). In addition, eight microbial taxa were considered as potentially causal features under the nominal significance (P < 0.05): Actinobacteria, Lachnospiraceae, Methanobacteria, Bacillales, Methanobacteriales, Coprococcus2, Gordonibacter, and Veillonella. According to the reverse-direction MR study findings, the gut microbiota was not significantly affected by ITP. There was no discernible horizontal pleiotropy or instrument heterogeneity. Finally, GO enrichment analyses showed how the identified microbial taxa participate in ITP through their underlying biological mechanisms. Several microbial taxa were discovered to be causally linked to ITP in this MR investigation. The findings improve our understanding of the gut microbiome in the risk of ITP.

Evaluation of potential adverse events following COVID-19 mRNA vaccination among adults aged 65 years and older: Two self-controlled studies in the U.S.

BackgroundOur near-real-time safety monitoring of 16 adverse events (AEs) following COVID-19 mRNA vaccination identified potential elevation in risk for six AEs following primary series and monovalent booster dose administration. The crude association with AEs does not imply causality. Accordingly, we conducted robust evaluation of potential associations. MethodsWe conducted two self-controlled case series studies of COVID-19 mRNA vaccines (BNT162b2 and mRNA-1273) in U.S. Medicare beneficiaries aged ≥ 65 years. Adjusted incidence rate ratio (IRRs) and 95 % confidence intervals (CIs) were estimated following primary series doses for acute myocardial infarction (AMI), pulmonary embolism (PE), immune thrombocytopenia (ITP), disseminated intravascular coagulation (DIC); and following monovalent booster doses for AMI, PE, ITP, Bell’s Palsy (BP) and Myocarditis/Pericarditis (Myo/Peri). ResultsThe primary series study included 3,360,981 individuals who received 6,388,542 primary series doses; the booster study included 6,156,100 individuals with one monovalent booster dose. The AMI IRR following BNT162b2 primary series and booster was 1.04 (95 % CI: 0.91 to 1.18) and 1.06 (95 % CI: 1.003 to 1.12), respectively; for mRNA-1273 primary series and booster, 1.01 (95 % CI: 0.82 to 1.26) and 1.05 (95 % CI: 0.998 to 1.11), respectively. The hospital inpatient PE IRR following BNT162b2 primary series and booster was 1.19 (95 % CI: 1.03 to 1.38) and 0.86 (95 % CI: 0.78 to 0.95), respectively; for mRNA-1273 primary series and booster, 1.15 (95 % CI: 0.94 to 1.41) and 0.87 (95 % CI: 0.79 to 0.96), respectively. The studies’ results do not support that exposure to COVID-19 mRNA vaccines elevate the risk of ITP, DIC, Myo/Peri, and BP. ConclusionWe did not find an increased risk for AMI, ITP, DIC, BP, and Myo/Peri and there was not consistent evidence for PE after exposure to COVID-19 mRNA primary series or monovalent booster vaccines. These results support the favorable safety profile of COVID-19 mRNA vaccines administered in the U.S. elderly population.

The Impact of Human Platelet Antigen Allele on Antiplatelet Antibodies and Cryoglobulins in Patients with Primary Immune Thrombocytopenia and Hepatitis C Virus-Associated Immune Thrombocytopenia.

Human platelet antigens (HPAs) are alloantigens associated with antiplatelet alloantibodies and the risk of immune thrombocytopenia (ITP). However, few studies have investigated associations among HPAs, antiplatelet autoantibodies, and cryoglobulins. We enrolled 43 patients with primary ITP, 47 with hepatitis C virus-associated ITP (HCV-ITP), 21 with hepatitis B virus-associated ITP (HBV-ITP), 25 controls with HCV, and 1013 normal controls. We analyzed HPA allele frequencies, including HPA1-6 and 15, antiplatelet antibodies binding to platelet glycoprotein (GP) IIb/IIIa, Ia/IIa, Ib/IX, IV, human leukocyte antigen class I, cryoglobulin IgG/A/M, and their associations with thrombocytopenia. In the ITP cohort, HPA2ab, rather than HPA2aa, predicted a low platelet count. HPA2b was associated with the risk of developing ITP. HPA15b was correlated with multiple antiplatelet antibodies. In HCV-ITP patients, HPA3b was correlated with anti-GPIIb/IIIa antibodies. HCV-ITP patients with anti-GPIIb/IIIa antibodies had a higher positive rate of cryoglobulin IgG and IgA compared with those without anti-GPIIb/IIIa antibodies. Overlapping detection was also found among other antiplatelet antibodies and cryoglobulins. Like the antiplatelet antibodies, cryoglobulins were associated with clinical thrombocytopenia, implying their close relationship. Finally, we extracted cryoglobulins to confirm the exhibition of cryoglobulin-like antiplatelet antibodies. In contrast, in primary ITP patients, HPA3b was correlated with cryoglobulin IgG/A/M rather than anti-GPIIb/IIIa antibodies. HPA alleles were associated with antiplatelet autoantibodies and had different impacts in primary ITP and HCV-ITP patients. HCV-ITP was considered to be a symptom of mixed cryoglobulinemia in HCV patients. The pathophysiology may differ between these two groups.

Eradication therapy may decrease the risk of immune thrombocytopenia after Helicobacter pylori infection: a retrospective cohort study in Taiwan

BackgroundHelicobacter pylori (HP) eradication therapy (HPE) is recommended for patients with unexplained immune thrombocytopenia (ITP); however, the role of HPE in preventing ITP in patients with HP infection remains unclear. Therefore, this study was designed to clarify it.MethodsThis study was conducted at a tertiary medical center and included all adult patients with HP infection between January 1, 2016 and December 31, 2018. We compared the risk of developing ITP between patients with and without HPE. All patients were followed up until December 31, 2020.ResultsAfter excluding patients with thrombocytopenia, 1995 adult patients with HP infection, including 1188 patients with HPE and 807 patients without HPE, were included in this study. The mean age of the patients with HPE was 57.9 years, whereas that of those without HPE was 61.6 years. The percentage of males was 56% in patients with HPE and 59% in those without HPE. Patients without HPE had a higher risk of ITP than those with HPE after adjusting for age, sex, the Charlson Comorbidity Index, and comorbidities [adjusted odds ratio (OR) 1.76; 95% confidence interval (CI) 1.16–2.68]. Stratified analyses showed that the higher risk was found only in males (adjusted OR: 1.70; 95% CI 1.03–2.80). In addition to HPE, male sex and anemia were independent predictors of ITP in patients with HP infection.ConclusionThis study showed that adult patients with HP infection not receiving HPE had a higher risk of developing ITP. We suggest that HPE should be considered, particularly in males and those who have anemia, to prevent ITP.

Relationship between coronavirus disease 2019 vaccination and the risk of immune thrombocytopenia

To study the relationship between coronavirus disease 2019 (COVID-19) vaccination and the risk of immune thrombocytopenia (ITP). A retrospective analysis was conducted on children aged 3-17 years with newly diagnosed ITP who were hospitalized in Children's Hospital Affiliated to Zhengzhou University from November 2021 to December 2022. Clinical data and COVID-19 vaccination status were compared among three groups: ITP patients vaccinated within 12 weeks before onset, vaccinated more than 12 weeks before onset, and unvaccinated. Changes in serum immunoglobulin and complement levels were analyzed among five groups: ITP patients vaccinated <4 weeks before onset, 4-<8 weeks before onset, 8-<12 weeks before onset, ≥12 weeks before onset, and unvaccinated. A case-control design was used to estimate the risk of ITP: 387 children aged 3-17 years with fractures hospitalized during the same period in the emergency department of the hospital were selected as the control group, and the exposure to COVID-19 vaccination within 12, 8, and 4 weeks before onset in ITP children was compared to estimate the risk of ITP. Among 129 ITP children, there were no statistically significant differences in age, gender, rate of preceding infections, absolute platelet count at initial diagnosis, absolute lymphocyte count at initial diagnosis, bleeding score, positive anti-nuclear antibody rate, absolute platelet count after 4 days of treatment, recurrence rate, and proportion of patients with disease duration ≥3 months among the three groups vaccinated within 12 weeks before onset, vaccinated more than 12 weeks before onset, and unvaccinated (P>0.05). There was a statistically significant difference in serum immunoglobulin G, immunoglobulin A, and complement component 3 levels among the groups vaccinated <4 weeks, 4-<8 weeks, 8-<12 weeks, and ≥12 weeks before onset, and unvaccinated (P<0.05). The risk estimation results showed that COVID-19 vaccination within 12 weeks, 8 weeks, and 4 weeks before onset did not increase the risk of ITP (P>0.05). COVID-19 vaccination does not increase the risk of ITP.

Immune thrombocytopenia and pregnancy: an exposed/nonexposed cohort study

AbstractThe risk of immune thrombocytopenia (ITP) worsening during pregnancy and neonatal ITP (NITP) have never been prospectively studied. We included 180 pregnant and 168 nonpregnant women with ITP in a prospective, multicenter, observational cohort study. A total of 131 pregnant women with ITP were matched to 131 nonpregnant women with ITP by history of splenectomy, ITP status (no response, response, complete response), and duration. Groups were followed for 15 months. The primary outcome was the first occurrence of ITP worsening defined by a composite end point including bleeding events and/or severe thrombocytopenia (<30 × 109/L) and/or ITP treatment modification. We also studied the recurrence of ITP worsening and the incidence of NITP and risk factors. The first occurrence of ITP worsening did not differ between pregnant and nonpregnant women with ITP (53.4 per 100 person-years [95% confidence interval {CI}, 40.8-69.9] vs 37.1 [95% CI, 27.5-50.0]; hazard ratio {HR}, 1.35 [95% CI, 0.89-2.03], P = .16). Pregnant women with ITP were more likely to have recurrence of severe thrombocytopenia and treatment modification (HR, 2.71 [95% CI, 1.41-5.23], P = .003; HR, 2.01 [95% CI, 1.14-3.57], P = .017, respectively). However, recurrence of severe bleeding events was not different between groups (P = .4). Nineteen (14%) neonates showed NITP <50 × 109/L. By multivariable analysis, NITP was associated with a previous offspring with NITP and maternal platelet count <50 × 109/L within 3 months before delivery (adjusted odds ratio, 5.55 [95% CI, 1.72-17.89], P = .004 and 4.07 [95% CI, 1.41-11.73], P = .009). To conclude, women with ITP do not increase their risk of severe bleeding during pregnancy. NITP is associated with NITP history and the severity of maternal ITP during pregnancy. These results will be useful for counseling women with ITP.

SARS-CoV-2 vaccination in pediatric patients with immune thrombocytopenia.

SARS-CoV-2 vaccination in pediatric patients with immune thrombocytopenia.

FcγRIIa and FcγRIIIa genes polymorphism in Egyptian children with primary immune thrombocytopenia

IntroductionPhagocytosis of autoantibody-sensitized coated platelets through Fc gamma receptors on phagocytic cells is an important mechanism of thrombocytopenia in primary immune thrombocytopenia (ITP). ObjectiveWe aimed to investigate the contribution of the FcγRIIa and FcγRIIIa genes polymorphism to the risk of ITP and their association with disease characteristics in Egyptian children. MethodsA case control study was conducted on eighty children with primary ITP and eighty age and sex healthy matched subjects as a control group. The FcγRIIa and FcγRIIIa genes polymorphism was detected using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). ResultsWe found that the FcγRIIa‐131H and ‐131R allele frequencies were 51.3 % and 48.7%, respectively, in children with ITP, versus 75% and 25%, respectively, in controls (p = 0.002). The compound heterozygous HR genotype was significantly higher in ITP patients (p < 0.05). The FcγRIIIa-158F and ‐158V allele frequencies were 46.3% and 53.7%, respectively, in children with ITP, versus 70% and 30%, respectively, in controls (p = 0.002). The compound heterozygous VF genotype was significantly higher in ITP patients (p < 0.05). The combined HR/FV genotype was 47.5% in ITP patients, versus 10% in controls (p < 0.001). No significant difference was found between children with newly diagnosed ITP and those who developed chronic ITP, regarding the frequency distribution of the FcγRIIa and FcγRIIIa alleles and genotypes (p > 0.05). ConclusionThere is a possible association of the FcγRIIa and FcγRIIIa genes polymorphism with the risk for, and genetic susceptibility to ITP in Egyptian children, but large-scale studies are still needed to support our findings.

Immune Checkpoint-Related Gene Polymorphisms Are Associated With Primary Immune Thrombocytopenia.

Cancer immunotherapy by immune checkpoint blockade has been effective in the treatment of certain tumors. However, the association between immune checkpoints and autoimmune diseases remains elusive and requires urgent investigation. Primary immune thrombocytopenia (ITP), characterized by reduced platelet count and a consequent increased risk of bleeding, is an autoimmune disorder with a hyper-activated T cell response. Here, we investigated the contribution of immune checkpoint-related single-nucleotide polymorphisms (SNPs), including CD28, ICOS, PD1, TNFSF4, DNAM1, TIM3, CTLA4, and LAG3 to the susceptibility and therapeutic effects of ITP. In this case-control study, 307 ITP patients and 295 age-matched healthy participants were recruited. We used the MassARRAY system for genotyping immune checkpoint-related SNPs. Our results revealed that rs1980422 in CD28 was associated with an increased risk of ITP after false discovery rate correction (codominant, CT vs. TT, OR = 1.788, 95% CI = 1.178–2.713, p = 0.006). In addition, CD28 expression at both the mRNA and protein levels was significantly higher in patients with CT than in those with the TT genotype (p = 0.028 and p = 0.001, respectively). Furthermore, the T allele of PD1 rs36084323 was a risk factor for ITP severity and the T allele of DNAM1 rs763361 for corticosteroid-resistance. In contrast, the T allele of LAG3 rs870849 was a protective factor for ITP severity, and the T allele of ICOS rs6726035 was protective against corticosteroid-resistance. The TT/CT genotypes of PD1 rs36084323 also showed an 8.889-fold increase in the risk of developing refractory ITP. This study indicates that immune checkpoint-related SNPs, especially CD28 rs1980422, may be genetic factors associated with the development and treatment of ITP patients. Our results shed new light on prognosis prediction, disease severity, and discovering new therapeutic targets.

PTPN22 gene polymorphism as a genetic risk factor for primary immune thrombocytopenia in Egyptian children

ABSTRACT Objectives Several genetic and non-genetic risk factors are implicated in the etiology and pathogenesis of primary immune thrombocytopenia (ITP). Protein tyrosine phosphatase non-receptor 22 gene (PTPN22) plays an important role in regulation of signal transduction through the T-cell receptors. PTPN22 1858 C > T single nucleotide polymorphism was reported to be associated with increased risk of autoimmune diseases. There are very few studies investigating the role of PTPN22(SNP) 1858 C > T in childhood ITP. Methods This case-control study was designed for assessing the contribution of PTPN22 1858 C > T polymorphism to the risk of ITP in Egyptian children. Eighty children with newly diagnosed ITP were recruited from pediatric hematology out-patient clinic. Also, eighty age and sex-matched healthy children were enrolled as a control group. PTPN22 1858 C/T SNP gene polymorphism was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results Frequency of PTPN22 1858 C/T genotypes CT, CC, and TT were 32.5,55, and 12.5% in patients versus 10, 90, and 0% in controls (p < 0.05).TT genotype was significantly associated with higher risk of ITP (OR = 17.8(0.94–333.35), 95% CI, and P = 0.02). Conclusion PTPN22 gene polymorphism may play a pivotal role in genetic predisposition to ITP and disease progress in Egyptian children.

Predicting bleeding risk in a Chinese immune thrombocytopenia (ITP) population: development and assessment of a new predictive nomogram

The aim of this study was to develop a model that could be used to forecast the bleeding risk of ITP based on proinflammatory and anti-inflammatory factors. One hundred ITP patients were recruited to build a new predictive nomogram, another eighty-eight ITP patients were enrolled as validation cohort, and data were collected from January 2016 to January 2019. Four demographic characteristics and fifteen clinical characteristics were taken into account. Eleven cytokines (IFN-γ, IL-1, IL-4, IL-6, IL-8, IL-10, IL-17A, IL-22, IL-23, TNF-α and TGF-β) were used to study and the levels of them were detected by using a cytometric bead array (CBA) human inflammation kit. The least absolute shrinkage and selection operator regression model was used to optimize feature selection. Multivariate logistic regression analysis was applied to build a new predictive nomogram based on the results of the least absolute shrinkage and selection operator regress ion model. The application of C-index, ROC curve, calibration plot, and decision curve analyses were used to assess the discrimination, calibration, and clinical practicability of the predictive model. Bootstrapping validation was used for testing and verifying the predictive model. After feature selection, cytokines IL-1, IL-6, IL-8, IL-23 and TGF-β were excluded, cytokines IFN-γ, IL-4, IL-10, IL-17A, IL-22, TGF-β, the count of PLT and the length of time of ITP were used as predictive factors in the predictive nomogram. The model showed good discrimination with a C-index of 0.82 (95% confidence interval 0.73376–0.90 624) in training cohortn and 0.89 (95% CI 0.868, 0.902) in validation cohort, an AUC of 0.795 in training cohort, 0.94 in validation cohort and good calibration. A high C-index value of 0.66 was reached in the interval validation assessment. Decision curve analysis showed that the bleeding risk nomogram was clinically useful when intervention was decided at the possibility threshold of 16–84%. The bleeding risk model based on IFN-γ, IL-4, IL-10, IL-17A, IL-22, TGF-β, the count of PLT and the length of time of ITP could be conveniently used to predict the bleeding risk of ITP.

Impact of CD40 gene polymorphisms on the risk of immune thrombocytopenic purpura

ObjectivesTo evaluate the relationship between two common single nucleotide polymorphisms (SNPs) of CD40 gene (rs1883832 C/T and rs4810485 G/T) and the risk of immune thrombocytopenia (ITP) in the Egyptian population. MethodsA case-control study was conducted retrospectively on 101 cases with ITP and 97 healthy subjects. Two SNPs of CD40 gene (rs1883832 C/T and rs4810485 G/T) were genotyped via Taqman allele discrimination real-time PCR. The frequencies of different genetic models of both SNPs were calculated and compared between ITP cases and controls. Linkage analysis was performed between the studied SNPs. Odds ratio (OR) and 95% confidence interval (CI) were assessed using multinomial logistic regression analysis to determine the association of CD40 gene SNPs genotypes, alleles, and haplotypes with the risk of ITP. The odds ratio was further adjusted to the confounders for risk stratification. ResultsCD40 (rs1883832) TT genotype carriers have a significantly higher risk of ITP when compared to CC genotype carriers (adjusted OR: 3.792, 95%CI: 1.252–11.49, P = 0.018). T allele also represents 1.711-fold increased risk of ITP which is more evident in males (P = 0.016). No significant difference was observed in the frequency of CD40 (rs4810485 G/T) genetic models between cases and controls. Linkage disequilibrium was found between the two SNPs and revealed four main haplotypes (C-G; C-T; T-G; T-T) with a significantly higher frequency of T-G haplotype in ITP cases than in healthy controls which confers an increased risk of ITP development (OR: 2.349, 95%CI: 1.271–4.339, P = 0.006). ConclusionsCD40 gene SNP rs1883832 is associated with an increased risk of ITP development in the Egyptian population, while the SNP rs4810485 has no association. Moreover, T-G haplotype is a risk genetic model for ITP.

Risk of Immune Thrombocytopenia Induced By Influenza Vaccine. a Nationwide Population-Based Study in France

Introduction: Epidemiological studies suggest a risk of immune thrombocytopenia (ITP) following viral infections, particularly influenza. Conversely, an increased risk of ITP following vaccination has been proven for some vaccines like Measles-Mumps-Rubella vaccine. However, the risk of ITP induced by influenza vaccine is debated. Two case-controls studies has been conducted, with contradictory results: in the Berlin Case-Control Surveillance Study, an increased risk has been found (odds ratio - OR: 3.8 [95% confidence interval - CI: 1.5- 9.1]. Conversely, the French PGRx study suggested the absence of risk of ITP after influenza vaccination [OR: 0.9; 95% CI: 0.4-2.1]. These studies were limited by the number of ITP patients included (169 and 198, respectively) and other limitations. Therefore, we aimed to assess the risk of ITP induced by influenza vaccine in a nationwide cohort in France. Methods: We conducted a population-based study in France within the FAITH cohort (NCT03429660). This cohort is built within the National Health Database that links sociodemographic, hospital and out-hospital data. The FAITH cohort includes all adult patients with incident ITP in France since 2009. Patients are identified using a validated algorithm combining diagnosis codes and drug exposures (with very high positive predictive values). We included in the present study all patients with incident primary ITP aged ≥65 years at ITP diagnosis (indication of influenza vaccination in the general population in France) between July 2009 and June 2015. We assessed the link between influenza vaccine and ITP onset using two designs: a case-control and a self-controlled case series designs. In the case-control design, ITP cases were matched with four controls from the general population for age, sex and place of residency. Index dates for controls were similar to index dates of their matched cases. Cases and controls were compared for exposure to influenza vaccine in the 6 weeks before the index date using conditional logistic regression models adjusted for exposure to other drugs known as inducers of ITP. In the self-controlled case series study, only vaccinated ITP cases were included. The analysis compared the incidence of ITP within periods of risk (6 weeks following vaccination) to the incidence of ITP within other periods of time. We further excluded the 2 weeks prior to vaccine dispensing from the analysis to address selective survival bias (healthy vaccinee effect). Incidence rate ratios (IRRs) adjusted for seasonality were calculated. Results: We included 3,142 incident primary ITP patients aged ≥65 years matched with 12,528 controls in the case-control study. Overall, 147 cases (4.7%) and 579 controls (4.6%) were vaccinated with influenza vaccine during the 6 weeks prior to the index date (adjusted OR: 0.99; 95% CI: 0.80-1.23]). In the self-controlled case series study, 1,875 vaccinated ITP cases were included. Among them, 146 (7.8%) patients were diagnosed for ITP during one of the risk periods following vaccination. The adjusted IRR was 0.96 [95 CI%: 0.80-1.17]. Conclusion: This nationwide population-based study using two different designs showed no increased risk of ITP after influenza vaccination. Disclosures Moulis: Novartis pharma: Research Funding, Speakers Bureau; Amgen pharma: Research Funding, Speakers Bureau; CSL Behring: Research Funding.

Racial Variation in ITP Prevalence and Rate of Chronic Disease Suggests Biological Differences

Background: Immune thrombocytopenia (ITP) is the most common cause of acquired immune platelet destruction in children. Clinical symptoms range from asymptomatic to significant and even life-threatening bleeding, fatigue, and reduced health-related quality of life. About 75% of affected children experience spontaneous remission, with the remainder developing chronic ITP. Our clinical observations suggest a decreased prevalence of ITP among Black children, although no available studies have evaluated racial or ethnic predisposition to ITP or to chronic disease. We hypothesized that biological differences in Black children alter the prevalence of ITP, relative to the general population, and may affect disease course. Methods: A retrospective analysis evaluating race and ethnicity of all children with ITP treated at Texas Children's Hospital (TCH, Houston, TX) from January 2015-July 2019 was performed, and compared to both the Houston metropolitan area and the TCH Cancer Center 2018 race and ethnicity data. Of the 699 unique patients, race and ethnicity data were unavailable for 24, and 2 patients were excluded (1 with leukemia, 1 with bone marrow failure). The remaining patients were categorized as (1) White, non-Hispanic; (2) Black, non-Hispanic; (3) Hispanic; and (4) Other. Hispanic patients included those who self-identified as (1) White, Hispanic; (2) Black, Hispanic; (3) Asian, Hispanic; (4) Multi-race, Hispanic; and (5) Unknown race, Hispanic. Demographic data was then collected in a second ITP population derived from the Children's Hospital of Philadelphia (CHOP, Philadelphia, PA) and the surrounding metropolitan area. To match the distribution reported in the Houston metro area data, a comparison was conducted focusing on the proportion of Black non-Hispanic patients in each cohort. A chi-squared test with Yates correction was utilized to compare nonparametric categorical data using GraphPad Prism version 8.0.1 for Windows, GraphPad Software, San Diego, California, USA. A p-value of &amp;lt;0.05 was statistically significant. Results: At TCH, there were 673 evaluable ITP patients. Classifying by race only, 42 were Black (6.2%), 564 White (83.8%), and 67 Other (Asian, Mixed Race, Native American, 9.9%). There was a significantly smaller percentage of ITP patients identified as Black, non-Hispanic (n= 40, 5.9%) relative to both the Texas Children's Cancer Center (16% Black, non-Hispanic) and the Houston metropolitan area populations (16% Black, non-Hispanic, p&amp;lt;0.0001). These data are significant given that Texas Children's Hospital sees the majority of children in the Houston metropolitan area, and the demographic data for the Cancer Center accurately reflect the Houston population (see Table). Black, non-Hispanic patients with ITP were more likely to have chronic disease (40% chronic, n=16) than the expected 20-25% in the overall pediatric ITP population. Many of the patients described as Black, non-Hispanic had secondary ITP (20.0%, n=8), most commonly due to systemic lupus erythematosus (SLE), a condition more common amongst Black patients. These findings were consistent at CHOP, with 7% of the 311 included patients classified as Black (n=22), 76% White (n=236) and 17% Other (n=54 including Asian, Middle Eastern, Mixed Race and Native American/Pacific Islander). Again, these proportions are in contrast to the general CHOP patient population (22% Black, 55.5% White and 22.5% other) and the Philadelphia metro population (42.5% Black, 41.5% White, 16% Other). The frequency of chronic ITP was also increased in Black patients in the CHOP cohort (39%, n=7). Conclusions: This analysis suggests a significant difference in the prevalence of ITP by race in children at two large tertiary care centers in the US. We found that Black children were less likely to develop ITP but those who did were more likely to develop chronic disease relative to other races. Race and ethnicity data at both institutions more closely matched their surrounding metropolitan areas, suggesting the observed differences are not due to care or access barriers. These findings support the possibility that damaging genetic variants, altered gene expression and/or other biological differences in immune response may lead to increased risk of ITP in White children, or protective factors result in reduced prevalence of ITP in Black children. Further research to explore these differences is ongoing. Figure Disclosures Lambert: CSL Behring: Consultancy; Amgen: Consultancy, Other; Bayer: Other: Ad boards; Novartis: Other: Ad boards, Research Funding; Shionogi: Consultancy; Kedrion: Consultancy; Sysmex: Consultancy; AstraZeneca: Research Funding; PDSA: Research Funding. Despotovic:Dova: Honoraria; Novartis: Research Funding; Amgen: Research Funding.

Risk of Vaccine-Induced Immune Thrombocytopenia in Children. Nationwide Case Cross-over and Self-Controlled Case Series Studies in France

Introduction: The association of measles, mumps and rubella (MMR) vaccination with immune thrombocytopenia (ITP) occurrence has been shown. The risk of ITP with other vaccines is still not known. This study was aimed at assessing the association of recommended vaccinations in children with ITP occurrence.Methods: We conducted a population-based study in France including all children newly diagnosed for primary ITP between July 2009 and June 2015. This cohort was built using a validated algorithm in the nationwide French health insurance database (SNDS). We assessed the risk of ITP with MMR vaccine, all combined vaccines containing diphtheria, tetanus and poliomyelitis (DTP) vaccines, pneumococcal and meningococcal C vaccines. We used two self-controlled designs: a case cross-over and a self-controlled case series. For the case cross-over, we compared the frequency of exposure to vaccines during a 6-week period immediately preceding the event (case period) with the frequency of exposure during a previous time period (control period, having the same duration as the case period). We performed sensitivity analyses using 8- and 12-week periods. Analyses were adjusted for exposure to other drugs known as inducers of ITP and seasonality. Odds ratios (OR) and their 95% confidence intervals (CI) were calculated. For the self-controlled case series, we compared the ITP incidence within periods of risk (following vaccination, named exposure period) with the incidence within the control period of non-exposure. The exposure period was defined by the 6 weeks after the vaccine dispensing in the principal analysis (8 and 12 weeks in sensitivity analyses). We further excluded the 2 weeks prior to vaccine dispensing from the non-exposure period to address selective survival bias (healthy vaccinee effect). The observation period was censored at ITP occurrence, due to variation of vaccination probability after ITP diagnosis and to the impossibility to distinguish ITP relapses from chronic ITP in the database. Analyses were adjusted for seasonality. Incidence rate ratios (IRRs) and their 95% CI were calculated. We assessed the exposure to each vaccine, and conducted subgroup analyses in patients without any concurrent vaccination during case and control periods for the case cross-over study and exposure periods for the self-controlled case series study. We also calculated the number of ITP cases occurring during the 6 weeks after vaccination divided by the number of vaccine doses dispensed in the French children population during the study period.Results: We included 2,549 newly diagnosed primary ITP children. Among them, median age was 5.1 years and 46.5 % were females; 41.4% had been exposed to at least one studied vaccine before ITP onset. The results of the principal analysis are detailed in the Table. There was an increased occurrence of ITP following MMR vaccination (OR: 1.60, 95% CI: 1.09-2.34; IRR: 1.30, 95% CI: 0.95-1.80). Analyses excluding the patients with concurrent vaccination, notably meningococcal vaccination, led to similar results (OR: 1.66, 95% CI: 1.02-2.71; IRR: 1.39, 95% CI: 0.80-2.42). There was also an increased occurrence of ITP with the meningococcal C vaccine (OR: 1.92, 95% CI: 0.95-3.86; IRR: 1.40, 95% CI: 0.86-2.29). Analyses conducted in patients without any concurrent vaccination, notably MMR vaccination, confirmed these results with wide 95% CI because of fewer patients included (OR: 1.64, 95% CI: 0.57-4.71; IRR: 1.64, 95% CI: 0.69-3.86). No association was observed between other vaccines and ITP occurrence. The numbers of ITP cases occurring in the 6 weeks following vaccination per million doses dispensed were 8.2 for pneumococcal, 9.2 for DTP, 9.6 for meningococcal and 11.5 for MMR vaccines. Of note, these numbers overestimate the probability of vaccine-induced ITP. Indeed, they are ITP cases chronologically compatible with vaccine adverse reaction without any individual causality assessment (a worst-case scenario considering that all cases were triggered by vaccines).Conclusion: This study showed an increased occurrence of ITP after MMR and meningococcal C vaccines. It is reassuring for other vaccines. We cannot exclude temporal association with MMR and meningococcal C vaccines due to the peak of ITP incidence at 12 months of age in the general population. However, vaccine-induced ITP is a very rare event, which does not cast doubt on the interest of vaccination. DisclosuresNo relevant conflicts of interest to declare.