Measurements of immature platelets with haematology analysers are of limited value to separate immune thrombocytopenia from bone marrow failure

Detection of immature platelets in the circulation may help to dissect thrombocytopenia due to platelet destruction from bone marrow failure (BMF ). We prospectively tested the predictive value of immature platelets, measured as immature platelet fraction (IPF ) on the XE‐5000 (Sysmex, Kobe, Japan) or percentage of reticulated platelets (rPT ) on the CD Sapphire (Abbott Diagnostics, Santa Clara, CA, USA) to separate immune thrombocytopenia (ITP ) from BMF (leukaemia, myelodysplastic syndrome, aplastic anaemia). We analysed 58 samples of patients with BMF , 47 samples of patients with ITP and 97 controls. Median rPT (CD Sapphire) was increased to 9·0% in ITP and to 10·9% in BMF , compared to 1·9% in controls. Median IPF (XE‐5000) was 16·2% in ITP , 10·2% in BMF and 2·5% in controls. We found an inverse correlation between high fractions of immature platelets and low platelet counts in thrombocytopenic samples regardless of the diagnosis. In conclusion, we observed a broad overlap of immature platelets between ITP and BMF , which may be caused by an accelerated release of immature platelets in any thrombocytopenic state and decreased production in many patients with ITP . Despite this, IPF (XE‐5000) had some power to discriminate ITP from BMF , whereas rPT (CD Sapphire) was of no predictive value.     

The beta 1 tubulin R307H single nucleotide polymorphism is associated with treatment failures in immune thrombocytopenia (ITP)

Predictive biomarkers are needed in immune thrombocytopenia (ITP). Single nucleotide polymorphisms (SNPs) in beta 1 tubulin are potential candidates, as beta 1 tubulin is integral for platelet production and function, and SNPs in beta 1 tubulin have been associated with distinct phenotypes in platelets. We investigated the most prevalent beta 1 tubulin SNP (R307H) as a biomarker in patients with ITP via a retrospective chart review. Allelic frequencies between a group of 191 ITP patients and a healthy control group showed no difference, suggesting no direct aetiological role for the SNP in ITP. However, over similar periods of follow‐up, both heterozygote and homozygote minor allele ITP patients were treated with significantly more treatment modalities and had significantly higher risk of failure to immune‐modulatory therapies [relative risk (RR) = 1·5, 95% confidence interval (CI) = 1·1–2·1; P = 0·01]; with rituximab, in particular, ITP patients with the SNP experienced a 58% failure rate (RR = 1·6, 95%CI = 1·03–2·5; P = 0·04). Analysis of the absolute immature platelet fraction (A‐IPF) as a marker of platelet production showed that SNP patients had significantly higher median A‐IPFs compared to non‐SNP patients when complete responses were achieved using immune modulatory therapies. The data suggest that the beta 1 tubulin R307H SNP has potential for use as a biomarker in ITP and may affect platelet turnover.     

Correlation between immature platelet fraction and reticulated platelets. Usefulness in the etiology diagnosis of thrombocytopenia

Background: Reticulated platelets (RP) are a surrogate marker for megakaryocytic activity, but the limitation of this determination is the lack of standardization of methodology. The determination of the immature platelet fraction (IPF) is performed in a simple, automated, and reproducible way between laboratories. We analyzed the correlation between IPF and RP, and usefulness of IPF in patients with thrombocytopenia. Methods: RP were determined by flow cytometry using double staining with thiazole orange and CD61 PerCP^®. IPF was performed with Sysmex XE2100 analyzer. We used a control group with normal platelets, and thrombocytopenic patients were classified into three groups: Group 1. Central thrombocytopenia, Group 2. Thrombocytopenia as a result of enhanced peripheral platelet destruction, and Group 3. Peripheral non‐immune thrombocytopenia by abnormal distribution. Results: Fourteen controls and 66 patients were analyzed. Group 1: 25 patients, they had mean and confidence interval 95% (95% CI) for IPF 8.67% (6.49–10.46%) and RP 4.08% (2.86–5.30%). Group 2: 20 patients, they had mean and 95%CI for IPF 16.80% (12.20–21.39%) and RP 16.14% (9.89–22.40%). Group 3: 21 patients, they had mean and 95% CI for IPF 9.04% (6.95–11.14%) and RP 5.23% (3.41–7.05%). The overall Pearson linear correlation between IPF and RP was r: 0.65. There were statistically significant differences in values of IPF and RP between Group 2 and the other two groups (P < 0.01). Conclusion: There is a good correlation between IPF and RP mainly in thrombocytopenia by peripheral destruction. Determination of IPF is an easy technique in their implementation, standardized and reproducible, so it could be a useful screening technique in patients with thrombocytopenia.     

IVIg treatment increases thrombin activation of platelets and thrombin generation in paediatric patients with immune thrombocytopenia

Clinical manifestations and laboratory parameters of haemostasis were investigated in 23 children with newly diagnosed immune thrombocytopenia (ITP) before and after intravenous immunoglobulin (IVIg) treatment. ITP patients with platelet counts of less than 20 × 10⁹/L and mild bleeding symptoms, graded by a standardized bleeding score (BS), were compared with healthy children with normal platelet counts and children with chemotherapy-related thrombocytopenia. Markers of platelet activation and platelet apoptosis in the absence and presence of platelet activators were analysed by flow cytometry; thrombin generation in plasma was determined. ITP patients at diagnosis presented with increased proportions of platelets expressing CD62P and CD63 and activated caspases, and with decreased thrombin generation. Thrombin-induced activation of platelets was reduced in ITP compared with controls, while increased proportions of platelets with activated caspases were observed. Children with a higher BS had lower proportions of CD62P-expressing platelets compared with those with a lower BS. IVIg treatment increased the number of reticulated platelets, the platelet count to more than 20 × 10⁹/L and improved bleeding in all patients. Decreased thrombin-induced platelet activation, as well as thrombin generation, were ameliorated. Our results indicate that IVIg treatment helps to counteract diminished platelet function and coagulation in children with newly diagnosed ITP.     

Flow cytometric analysis of platelet cyclooxygenase-1 and -2 and surface glycoproteins in patients with immune thrombocytopenia and healthy individuals

Immature platelets may contain more platelet enzymes such as cyclooxygenase (COX)-1 and COX-2 than mature platelets. Patients with immune thrombocytopenia (ITP) have a higher fraction of immature platelets and can therefore be utilized as a biological model for investigating COX-1 and COX-2 platelet expression. The aims were to develop flow cytometric assays for platelet COX-1 and COX-2 and to investigate the COX-1 and COX-2 platelet expression, platelet turnover, and platelet glycoproteins in ITP patients (n = 10) compared with healthy individuals (n = 30). Platelet count and platelet turnover parameters (mean platelet volume (MPV), immature platelet fraction (IPF), and immature platelet count (IPC)) were measured by flow cytometry (Sysmex XE-5000). Platelet COX-1, COX-2, and the glycoproteins (GP)IIb, IX, Ib, Ia, and IIIa were all analyzed by flow cytometry (Navios) and expressed as median fluorescence intensity. COX analyses were performed in both whole blood and platelet rich plasma (PRP), whereas platelet glycoproteins were analyzed in whole blood only. ITP patients had significantly lower platelet count (55 × 10⁹/L) than healthy individuals (240 × 10⁹/L, p < 0.01), but a higher MPV (p = 0.03) and IPF (p < 0.01). IPC was similar for the two groups (p = 0.74). PRP had significantly lower MPV (p < 0.01) and significantly higher platelet count and IPC (both p-values <0.03) when compared with whole blood. IPF was similar for PRP and whole blood (p = 0.18). COX-1 expression was 10 times higher and COX-2 expression was 50% higher in PRP than in whole blood (p_COX-1 < 0.01, p_COX-2 < 0.01). Platelet COX-1 expression was higher in ITP patients than healthy individuals using whole blood (p_COX-1 < 0.01) and PRP, though this was nonsignificant in PRP (p_COX-1 = 0.17). In ITP patients, positive correlations were found between platelet turnover and COX-1 expression (all p-values <0.01, rho = 0.80–0.94), whereas healthy individuals showed significant though weaker correlations between platelet turnover and COX-1 and COX-2 expressions (all p-values <0.03, rho = 0.44–0.71). GPIIb, IX, and Ib expression was increased in ITP patients compared with healthy individuals (all p-values < 0.03). GPIIb, IX, Ib, and IIIa showed positive correlations with platelet turnover in ITP patients (all p-values <0.02, rho = 0.71–0.94), but weak and nonsignificant correlations in healthy individuals (all p-values >0.14, rho = 0.11–0.28). In conclusion, ITP patients expressed higher COX-1 and platelet glycoprotein levels than healthy individuals. COX-1 and platelet glycoproteins demonstrated positive correlations with platelet turnover in ITP patients. In healthy individuals, COX-1 and COX-2 expression correlated positively with platelet turnover. PRP was more sensitive compared with whole blood as regards determination of COX. Therefore, PRP is the recommended matrix for investigating COX-1 and COX-2 in platelets.     

Evaluation of the immature platelet fraction in the diagnosis and prognosis of childhood immune thrombocytopenia

Rapid assessment of platelet production would distinguish between thrombocytopenia due to decreased platelet production or increased peripheral platelet destruction. We evaluated the value of immature platelet fraction (IPF) in differentiating immune thrombocytopenia (ITP) from thrombocytopenia secondary to bone marrow failure and its potential use as a prognostic marker. Forty-one young patients with ITP were compared with 14 patients with hematological malignancies under chemotherapy, representing a control group with thrombocytopenia due to bone marrow suppression and 30 age- and sex-matched healthy controls. Patients were studied stressing on bleeding manifestations, organomegaly/lymphadenopathy and therapy. Complete blood count including IPF was performed using Sysmex XE-2100. ITP patients were classified into two subgroups: acute ITP with spontaneous resolution within 3 months from diagnosis and chronic ITP that lasted ≥1 year from diagnosis. Median IPF was 11.8% in patients with ITP, 7% in those with hematological malignancy and 3% in the control group (p?<?0.001). ITP patients had significantly higher mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR) and IPF compared with patients with malignancy or healthy controls, while plateletcrit (PCT) was significantly lower in ITP patients than other groups (p?<?0.001). IPF was increased in patients with chronic ITP compared with acute ITP group (p?<?0.001). Patients with active ITP had the highest IPF followed by those in partial remission, while ITP patients in remission had the lowest IPF. IPF was positively correlated to the number of lines of treatment used, MPV, PDW and P-LCR, while negatively correlated to platelet count and PCT among ITP patients (p?<?0.001). Multiple regression analysis showed that platelet count and P-LCR were independently related to IPF. ROC curve analysis revealed that the cut-off value of IPF at 9.4% could be diagnostic for ITP patients with a sensitivity of 88% and a specificity of 85.7%. We suggest that IPF may be a rapid and inexpensive automated marker for etiology of thrombocytopenia and can be integrated as a standard parameter to evaluate the thrombopoietic state of the bone marrow. It may be considered as a potential prognostic marker for the development of chronic ITP.     

Multicentre,randomised phase III study of the efficacy and safety of eltrombopag in Chinese patients with chronic immune thrombocytopenia

Eltrombopag, a thrombopoietin receptor agonist, raises platelet counts and reduces bleeding in patients with immune thrombocytopenia (ITP ). In Chinese patients, eltrombopag was evaluated at an initial dose of 25 mg, vs. 50 mg for non‐Asians, because the plasma exposure of eltrombopag is higher in East Asians. A multicentre, double‐blind, randomised, placebo‐controlled, 8‐week, phase III study enrolled 155 patients with chronic, previously treated ITP . Dosage could be adjusted (25–75 mg/day) to maintain platelet counts 50–250 × 10⁹/l. The primary efficacy endpoint was the proportion of patients with a platelet count ≥50 × 10⁹/l after Day 42. Pharmacokinetics and pharmacodynamics of eltrombopag were analysed in an open‐label extension. After Day 42, 57·7% of eltrombopag‐treated and 6·0% of placebo‐treated patients achieved platelet counts ≥50 × 10⁹/l. Odds of achieving a platelet count ≥50 × 10⁹/l were 26·08 times greater with eltrombopag than placebo (P  <  0·001). Compared with placebo, time to response and duration of response were better with eltrombopag (P  <  0·001) and the odds of any bleeding were reduced by 72% (P  =  0·001). Tolerability, pharmacokinetics, and pharmacokinetics/pharmacodynamics were similar to previous findings in East Asian patients. In conclusion, in Chinese patients with chronic ITP , eltrombopag 25 mg once daily, elevated platelet counts to a safe range and reduced bleeding.     

Autoantibody-mediated complement activation on platelets is a common finding in patients with immune thrombocytopenic purpura (ITP)

Background: It is commonly accepted that antibody‐mediated removal of platelets represents a major mechanism of platelet destruction in immune thrombocytopenic purpura (ITP). Although complement activation may participate in platelet clearance, frequency and specificity of complement activation have not yet been studied systematically in ITP. Patients and methods: We examined blood samples from 240 patients with ITP. Samples were assessed for the presence of free and bound platelet autoantibodies by a standard glycoprotein‐specific assay (monoclonal antibody‐specific immobilization of platelet antigens). The ability of all sera to fix complement to a panel of human platelets was investigated in a complement fixation (CF) assay. Fixation of C1q to isolated GP IIb/IIIa was assessed by flow cytometry. Results: Glycoprotein‐specific autoantibodies were detected as platelet‐bound antibodies in 129 (54%) and as additional free antibodies in 26 (11%) and were undetectable in 111 (46%) patients. Assessing these subgroups for CF, 103 (65%), 21 (81%), and 33 (30%) sera gave positive results. If GP IIb/IIIa was absent from the test platelets, 81 (67%) lost their ability to fix complement; if GP Ib/IX was absent, 37 (30%) lost their ability to fix complement. C1q fixation to immunobeads coated with GP IIb/IIIa was observed in 50% of sera containing anti‐GP IIb/IIIa antibodies. Conclusions: In a significant number of patients with chronic ITP, platelet autoantibodies are capable of activating the classical complement pathway. CF is even present in ITP sera without detectable autoantibodies, indicating that current techniques for autoantibody detection may be insufficient. The major targets for complement‐fixing autoantibodies in ITP are GP IIb/IIIa and GP Ib/IX.     

Procoagulant profile in patients with immune thrombocytopenia

Despite their low platelet count some immune thrombocytopenia (ITP) patients seldom bleed, indicating the presence of factors to compensate thrombocytopenia. Moreover, ITP patients may have an increased risk for thrombosis. These facts suggest the presence of procoagulant mechanisms that have not been clarified yet. The aim of this study was to identify these possible factors. Moreover, the utility of rotational thromboelastometry (ROTEM^®) to test haemostasis in these patients was also evaluated. Patients with ITP presented a procoagulant profile due to an increased amount of platelet‐ and red cell‐microparticles, an increased resistance to protein C and the formation of a clot more resistant to fibrinolysis due to augmented levels of plasminogen activator inhibitor‐1, which might reflect an endothelial damage/activation in ITP patients. Despite increased maximum clot firmness and reduced lysis, ROTEM^® profiles showed a prolonged clotting time that might rely on the presence of anti‐platelet antibodies as suggested by the increased lagtime in thrombin generation test caused by plasma from ITP patients on platelets from healthy controls. These results indicate the need to individualize therapeutic treatment for ITP patients, considering their procoagulant profile and the presence of concomitant risk factors. Moreover, ROTEM^® appeared to be useful for evaluating haemostasis in ITP patients.     

Effect of pregnancy on the course of immune thrombocytopenia: a retrospective study of 118 pregnancies in 82 women

In women with pre‐existing immune thrombocytopenic purpura (ITP), the effect of pregnancy on the course of the disease is poorly known. We performed a dual‐centre retrospective cohort study of 118 pregnancies in 82 women with primary ITP. In early pregnancy, the platelet count was <100 × 10⁹/l in 35·6% of pregnancies. During pregnancy the median platelet count nadir was 66 × 10⁹/l (25th–75th percentile: 42–117), with platelet count <30 × 10⁹/l for 26 pregnancies (22%). In 49% of pregnancies, a significant decrease of the platelet count required treatment at least transiently in preparation for delivery. At the time of delivery, the median platelet count was 110 × 10⁹/l (77–155). Compared to before pregnancy, at 3 months post‐partum, only 11% of pregnancies [95% confidence interval (95% CI): 6·8–20·2] showed disease worsening. Previous splenectomy was the only factor significantly associated with ITP worsening after pregnancy (53·9% vs. 10·3%, P < 0·001). For 8·3% of the pregnancies (95% CI: 3·8–15·1), neonatal thrombocytopenia required treatment, especially in case of previous maternal splenectomy (adjusted odds ratio 16·7, 95% CI: 2·61–106). The overall risk of exacerbation of ITP and severe thrombocytopenia during pregnancy is acceptable.     

Glycocalicin in the diagnosis and management of immune thrombocytopenia

Abstract: We studied glycocalicin (GC), expressed as plasma GC concentration and as GC index (ratio to platelet count), in 129 thrombocytopenic patients (platelet count <100×10⁹/1) and 60 sex- and age-matched controls. Seventy-two patients had idiopathic immune thrombocytopenia, 32 secondary immune thrombocytopenia, 8 microangiopathic thrombocytopenia and 17 thrombocytopenia secondary to bone marrow aplasia. Patients with immune thrombocytopenia (ITP) were also subclassified, according to their clinical behaviour, as having active disease or being in spontaneous or therapy-induced partial remission. A significant correlation was found between glycocalicin levels and platelet count both in normals and in patients with bone marrow aplasia (r = 0.75). ITP patients showed a GC index significantly higher than controls (6.02±7.87 vs. 0.9±0.2, p<0.001). When ITP patients with similar platelet count (30–50×10⁹/l) were studied, the mean level of GC and the GC index were significantly higher in those patients with active disease than in those in remission (0.97±0.38 vs. 0.58±0.17 μg/ml, p<0.05; 6.41±2.64 vs. 3.44±0.94, p<0.05, respectively). A longitudinal study performed in 10 patients with different subtypes of ITP suggested a positive correlation between GC index and the activity of the disease. The GC value and GC index were significantly higher in patients with microangiopathic thrombocytopenia than in controls (1.44±0.73 vs. 0.8±0.16 μg/ml, p<0.01; and 18.77±22.23 vs. 0.9±0.2, p<0.001, respectively). The GC value was significantly lower in bone marrow failure (0.15±0.04 μg/ml, p<0.01) compared to controls, while no difference was observed in the GC index. Our data confirm that the GC index is helpful in differentiating thrombocytopenia due to increased platelet destruction from the one due to impaired production. In addition, the assay has been proven useful in the differential diagnosis of different ITP subtypes and their follow-up.     

The use of platelet serotonin release as a sensitive method for detecting anti-platelet antibodies and a plasma anti-platelet factor in patients with idiopathic thrombocytopenic purpura

Summary . The method described in this paper can be used for detecting anti-platelet iso-, hetero-, and drug-antibodies and for detecting a factor in the plasma of patients with idiopathic thrombocytopenic purpura that attaches to platelets (ITP factor). Plasma from the test subject, anticoagulated with citrate, is added to a suspension of normal platelets labelled with [¹⁴C] serotonin and the amount of radioactivity (serotonin) released is measured after incubating the mixture for 45 min at 37°C. Anti-platelet antibodies and drug antibodies that fix complement as well as isoantibodies not detectable in vitro by complement fixation or agglutination can be measured by this test. Plasma from 24 of 40 patients with ITP released significantly more serotonin than control plasmas (P < 0.025). False positive results were obtained in less than 2.5% of plasmas from normal individuals, from patients with a variety of diseases and from patients with secondary thrombocytopenia. However, plasmas from two of 13 patients with systemic lupus erythematosus and normal platelet levels gave positive results in the test. The 7S gamma globulin fractions of plasmas containing isoantibodies or ITP factor as well as acid eluates from platelets which had been incubated in these plasmas gave positive serotonin-release tests.     

Platelet apoptosis in paediatric immune thrombocytopenia is ameliorated by intravenous immunoglobulin

To evaluate the role of intravenous immunoglobulin (IVIg) in platelet apoptosis in paediatric immune thrombocytopenia, we investigated the platelets of 20 paediatric patients with acute immune thrombocytopenia (ITP), before and after IVIg treatment. Healthy children with platelet counts in the normal range and children with thrombocytopenia due to chemotherapy were enrolled as controls. All ITP patients presented with platelet counts <20 × 10⁹/l and bleeding symptoms. Markers of apoptosis, including activated caspase‐3, ‐8 and ‐9, phosphatidylserine (PS) exposure, mitochondrial inner membrane potential (ΔΨm), as well as platelet‐derived microparticle formation, were analysed by flow cytometry. After IVIg treatment, platelet counts increased to >20 × 10⁹/l in all patients. ITP patients had significantly increased proportions of platelets with activated caspase‐3, ‐8 and ‐9, with PS exposure, and with decreased ΔΨm, and demonstrated increased microparticle formation. Except for ΔΨm, these markers for apoptosis were reduced by IVIg treatment. Platelets of children with thrombocytopenia after chemotherapy also demonstrated increased microparticle formation and decreased ΔΨm, but no activation of caspases 3, 8 and 9 or PS exposure. In conclusion, in acute paediatric ITP, enhanced platelet apoptosis is seen at diagnosis that normalizes after IVIg treatment.     

Beyond the platelet count: immature platelet fraction and thromboelastometry correlate with bleeding in patients with immune thrombocytopenia

Platelet counts (PC) estimate bleeding risk in Immune Thrombocytopenia (ITP). We investigated whether measures of thromboelastometry and absolute immature platelet fraction (A‐IPF) would correlate better with acute bleeding score (ABS) than PC or mean platelet volume (MPV). Simultaneous determination of ABS, complete blood count and thromboelastometry was performed in 141 ITP patients; 112 underwent A‐IPF testing. Subgroup analyses were performed for paediatric subjects, PC <60 × 10⁹/l and <30 × 10⁹/l. PC significantly inversely correlated with ABS in all subjects, PC <30 × 10⁹/l and total paediatric cohort. MPV did not correlate with ABS in any subgroup. Thromboelastometry measures of clot firmness, but not PC, significantly correlated with ABS in all subjects with PC <60 × 10⁹/l, and children with PC <60 × 10⁹/l and <30 × 10⁹/l. A‐IPF demonstrated stronger correlation with ABS than did PC among all subjects, those with PC <60 × 10⁹/l, all children and children with PC <30 × 10⁹/l (r = ?0·37; r = ?0·34; r = ?0·44; r = ?0·60) versus ABS with PC (r = ?0·36; ns; r = ?0·32; ns). Stronger correlations of both thromboelastometry measures of clot firmness and A‐IPF than PC with ABS suggest factors beyond PC, i.e. related to platelet function, contribute to ITP bleeding pathophysiology. Thromboelastometry, A‐IPF and ABS can be incorporated into routine or acute visits.     

Cognitive symptoms are common in immune thrombocytopenia and associate with autonomic symptom burden

Objectives: People with adult immune thrombocytopenia (ITP) are commonly thought to have an isolated blood disorder, but many also describe memory and concentration problems. Cognitive impairment commonly associates with autonomic dysfunction. Here, we quantified cognitive symptoms in a large cohort of patients with ITP compared with controls and explored the relationship with autonomic symptoms. Methods: Patients with ITP were approached in the UK via the national ITP Support Association and invited to complete Composite Autonomic Symptom Scale (COMPASS; measure of autonomic symptoms) and Cognitive Failures Questionnaire (CFQ) together with one from a friend of similar age and sex without ITP. Results: Three hundred and ninety‐eight patients with ITP completed measures with paired data from a representative group of 189 patients and controls (47%). Both autonomic and cognitive symptom burden were higher in ITP compared with controls (COMPASS score (48 ± 14 vs. 38 ± 12; P > 0.0001); CFQ (43 ± 17 vs. 36 ± 13; P < 0.0001). A positive relationship was seen between increasing cognitive symptoms and higher COMPASS score (P < 0.0001; r² = 0.1). Increasing cognitive symptoms did not associate with platelet count (P = 0.08, r² = 0.008). Multivariate analysis confirmed age and COMPASS independently associated with higher CFQ but not platelet count. Conclusions: Immune thrombocytopenia is more than a bleeding disorder; cognitive symptoms are common and independently associate with autonomic symptoms but not disease severity.     

Thrombotic risk in patients with immune thrombocytopenia and its association with antiphospholipid antibodies

Patients with immune thrombocytopenia (ITP) paradoxically have an increased risk of thrombosis. The presence of antiphospholipid antibodies (aPL) has been observed in a substantial proportion of ITP patients, but its clinical significance remains to be established. This study retrospectively investigated the prevalence and clinical significance of aPL in ITP patients and assessed the risk factors for thrombosis. One hundred and sixty‐five subjects with ITP were included in the study and followed for a mean period of 63·4 months. Sixty‐nine (41·6%) patients were positive for aPL at diagnosis, and their clinical characteristics and course of ITP were not different from those of aPL‐negative patients. Twenty‐one (12·7%) patients developed a thrombotic event during follow‐up and the cumulative incidence rate ratio of aPL‐positive to aPL‐negative patients for thromboembolism was 3·15 [95% confidence interval (CI) 1·21–8·17] after adjusting for confounding factors. Lupus anticoagulant and hypertension were identified by Cox regression analysis as independent risk factors for thrombosis [hazard ratio (HR) 4·1, 95% CI 1·4–11·9, P = 0·009 and HR 5·6, 95% CI 1·9–15·8, P = 0·001, respectively]. Our results showed that a substantial proportion of ITP patients were aPL‐positive, and that lupus anticoagulant and hypertension were independent risk factors for thrombosis. Detection of aPL can provide useful information for identifying patients at high‐risk for developing thrombosis.     

Determinants of platelet count in pediatric patients with congenital cyanotic heart disease: Role of immature platelet fraction

Objectives

Congenital heart defects are common noninfectious causes of mortality in children. Bleeding and thrombosis are both limiting factors in the management of such patients. We assessed the frequency of thrombocytopenia in pediatric patients with congenital cyanotic heart disease (CCHD) and evaluated determinants of platelet count including immature platelet fraction (IPF) and their role in the pathogenesis of thrombocytopenia.

Methods

Forty‐six children and adolescents with CCHD during pre‐catheter visits were studied; median age was 20.5 months. Complete blood count including IPF as a marker of platelet production and reticulated hemoglobin content (RET‐He) as a marker of red cell production and iron status were done on Sysmex XE 2100 (Sysmex, Japan). C‐reactive protein, prothrombin time (PT), Activated partial thromboplastin time (APTT) were also assessed.

Results

Thrombocytopenia was found in 6 patients (13%). PT was prolonged (P = .016) and IPF was significantly higher in patients with thrombocytopenia compared with patients with normal platelet count (14.15 ± 5.2% vs 6.68 ± 3.39%; P = .003). Platelet count was negatively correlated with IPF while significant positive correlations were found between IPF and hemoglobin, red blood cells (RBCs) count, hematocrit (Hct), PT, reticulocytes count, and immature reticulocyte fraction.

Conclusions

We suggest that elevated IPF in CCHD patients with thrombocytopenia may denote peripheral platelets destruction as an underlying mechanism. Hemoglobin level, RBCs count, Hct, and RET‐He were not significant determinants for platelet count in CCHD.     

Interleukin-10 gene polymorphism reflects the severity of chronic immune thrombocytopenia in Japanese patients

Introduction: T‐helper cell type 1 (Th1) polarization of the immune response has been documented in patients with chronic immune thrombocytopenia (ITP). Interleukin (IL)‐10 is the most important factor regulating Th1 and T‐helper type 2 cytokine synthesis. This study evaluated the impact of IL‐10 polymorphisms on both susceptibility to, and severity of, chronic ITP. Methods: We analyzed ‐1082(G/A), ‐812(C/T), and ‐592(C/A) IL‐10 polymorphisms in 90 patients with adult chronic ITP and 202 race‐ and sex‐matched healthy controls. Results: No significant differences in the genotype or haplotype frequencies were observed between the patient with chronic ITP and the control group. However, more patients with the ‐592AA genotype showed a severe thrombocytopenic state (platelet count <10 × 10⁹/l) than those with the ‐592CC/CA genotypes (44.1%vs. 19.6%, P = 0.01). Furthermore, more patients with the ATA/ATA haplotype showed a severe thrombocytopenic state than those without the ATA/ATA haplotype (44.1%vs. 19.6%, P = 0.01). Conclusion: According to our data, patients with low producer type of IL‐10 polymorphisms have more severe thrombocytopenia, suggesting that IL‐10 gene polymorphisms may reflect the severity of ITP.     

Factors predictive of neonatal thrombocytopenia in pregnant women with immune thrombocytopenia

To determine predictive factors for neonatal thrombocytopenia in deliveries with immune thrombocytopenia (ITP), we conducted a retrospective study at a tertiary hospital between 1997 and 2013. During this period, 30 women with ITP delivered 44 children. Neonatal thrombocytopenia (<100 × 10⁹/L) at birth was observed in seven neonates; four of these cases were severe (<50 × 10⁹/L). No cases were complicated by intracranial hemorrhage, and there was no neonatal mortality. Platelet counts at birth of neonates born to mothers, who had first been diagnosed with ITP during pregnancy were significantly higher than those born to mothers diagnosed with ITP before pregnancy. There were significant correlations between neonatal platelet counts in the first and second siblings at birth (P = 0.015) and at nadir (P = 0.035). Platelet counts of neonates born vaginally were significantly more likely to decline after birth than those delivered by cesarean section (13/16 vs. 10/23, P = 0.024). In conclusion, diagnosis of ITP before pregnancy was significantly associated with neonatal thrombocytopenia, and the platelet count of an older sibling is a strong predictor for that of the next baby. The delivery mode may be an indicator of the timing of platelet count nadir after birth.     

Immature platelet fraction related parameters in the differential diagnosis of thrombocytopenia

Abstract

The pathogenesis of thrombocytopenia can be divided into increased destruction (ID) of platelets in the peripheral blood and decreased production (DP) of platelets in the bone marrow. This study aimed to analyze the efficacy of immature platelet fraction (IPF) related parameters, including the IPF count (IPF#), IPF percentage (IPF%) and highly fluorescence IPF percentage (H-IPF%), measured by XN-9000, in the differential diagnosis of thrombocytopenia. One hundred and twenty healthy volunteers were enrolled in the healthy control (HC) group, and 180 thrombocytopenia patients were grouped into either the increased destruction (ID) group or the decreased production (DP) group according to their final diagnosis. IPF# was significantly lower in the DP group than in the ID and HC groups (P < .01). Among the three groups, the ID group had the highest IPF% and H-IPF%, and the HC group had the lowest IPF% and H-IPF%. The differences between the three groups were all statistically significant (P < .01). In differentiating the ID patients from the DP patients, the areas under the operating characteristics curve of IPF#, IPF% and H-IPF% were 0.859, 0.944 and 0.930, respectively. False positive rates were below 0.04 when IPF#, IPF% and H-IPF% were above 2.65, 7.55 and 2.35, respectively. IPF related parameters showed high efficacy in the differential diagnosis of thrombocytopenia. However, due to the small numerical values of the IPF related parameters in some thrombocytopenia patients, the fluctuations of IPF% and H-IPF% should also be taken into consideration. Though H-IPF% is a new parameter, its effectiveness in the differential diagnosis of thrombocytopenia is not better than IPF%’s.