Mean Immature Platelet Fraction Research Articles

Correlation between the Values of Immature Platelet Fraction and Mean Platelet Volume with the Extent of Coronary Artery Disease in Patients with Non-ST-Segment Elevation Myocardial Infarction

Introduction: The identification of new markers of thrombotic risk and early diagnosis of Non-ST-segment Elevation Myocardial Infarction (NSTEMI) could allow the optimization of the therapy and predict short and long-term prognosis. Aims and objective: We aimed to assess the impact of Immature Platelet Fraction (IPF) and Mean Platelet Volume (MPV) levels on the extent of Coronary Artery Disease (CAD) in patients with NSTEMI undergoing coronary angiography. Methods: This is a prospective observational study in which 100 subjects of Non-ST Elevation Myocardial Infarction were recruited. For the measurement of platelet count, IPF and MPV samples were analyzed by an automated hematology analyzer (Sysmex XN 1000). Patients were subjected to coronary angiography as per institutional protocol and the extent of coronary artery lesion was noted. Result: A cutoff of MPV (fL) ≥ 10.6 can predict the involvement of the left anterior descending artery (LAD) with a sensitivity of 84%, and a specificity of 50%. With the cutoff of IPF (%) ≥ 2.4, it can even predict the type of disease i.e., Double Vessel Disease (DVD), or Triple Vessel Disease (TVD) with a sensitivity of 97%, and a specificity of 19%. Mean IPF values and MPV levels were significantly higher in patients with LAD involvement i.e., 4.40 ± 1.72% (p = 0.003) and 12.45 ± 1.88 (p = 0.030) respectively than in patients without involvement of LAD i.e., 2.78 ± 1.50% and 11.08 ± 2.19 respectively. Conclusion: Immature platelet fraction and mean platelet volume were significantly associated with the involvement of the left anterior descending artery which was the most commonly involved vessel in patients with NSTEMI. Mean platelet volume was also associated with TVD which was statistically significant. MPV and IPF can be useful early independent hematologic markers to identify patients with a higher risk for significant CAD as they are readily available and inexpensive.

Myeloproliferative Neoplasms and Aspirin: Does Increased Platelet Turnover Matter?

Platelet aggregation tests and the analysis of thromboxane A2 metabolites [serum thromboxane B2 (TXB2) and urine 11-dehydro TXB2] are used to evaluate the efficacy of aspirin. In myeloproliferative neoplasms (MPNs), the immature platelet fraction (IPF) rises due to enhanced platelet turnover, and this has been thought to reduce the efficacy of aspirin. This phenomenon is overcome by the recommendation of aspirin intake in divided doses. We aimed to evaluate aspirin efficacy in patients who were receiving aspirin treatment of 100 mg/day. Thirty-eight MPN patients and 30 control patients (non-MPN patients who received a single daily dose of aspirin at 100 mg for nonhematological conditions) were enrolled. IPF, serum TXB2, and urine 11-dehydro TXB2 levels were measured and aggregation tests with arachidonic acid and adenosine diphosphate were performed by light transmission aggregometry (LTA). Mean IPF and TXB2 levels were higher in the MPN group (p=0.008 and p=0.003, respectively). IPF levels were lower in patients on cytoreductive therapy in the MPN group (p=0.001), but these values were similar between patients on hydroxyurea and the non-MPN group (p=0.72). TXB2 levels did not differ according to hydroxyurea treatment status but were higher in the MPN group compared to non-MPN patients (23.63 ng/mL and 19.78 ng/mL, respectively; p=0.04). TXB2 values were higher in patients with essential thrombocythemia and a history of thrombotic events (p=0.031). No difference was observed in LTA between the MPN and non-MPN patient groups (p=0.513). Higher levels of IPF and TXB2 in the MPN patient group indicated platelets that could not be inhibited by aspirin. It was observed that patients under cytoreductive therapy had lower IPF values, but the expected decrease in TXB2 levels was not observed. These findings suggest that a lack of response to aspirin may be due to additional intrinsic factors rather than increased platelet turnover.

Mean platelet volume and immature platelet fraction as predictors of early onset neonatal sepsis risk in neonates of 28-36 weeks gestational age

Background Early onset neonatal sepsis is a potential life-threatening problem for preterm infant. Diagnosing early onset neonatal sepsis is challenging. Difficulties in establishing diagnosis might cause delay definitive treatment.
 Objective To analyze for potential associations between early onset neonatal sepsis (EONS) risk and mean platelet volume (MPV) as well as immature platelet fraction (IPF) in neonates of 28-36 weeks gestational age.
 Methods A prospective cohort study was conducted at Dr. Hasan Sadikin General Hospital, Bandung, West Java. Mean platelet volume (MPV) and IPF were evaluated in the first ?6 hours of life and during the 48-72 hours after the first examination. This examination was followed by observation for sepsis development. Double logistic regression analysis was used.
 Results Of 115 subjects, 45 preterm infants (39.1%) developed early onset neonatal sepsis. The increase in both mean MPV and mean IPF were significantly different (P<0.05). Double logistic regression analysis revealed that an increase in mean MPV (ORadj=6.14; 95%CI 1.99 to 18.96; P=0.002) and mean IPF (ORadj=6.56; 95%CI 2.64 to 16.34; P<0.001) were significantly associated with increased risk of sepsis.
 Conclusion The MPV and IPF increase are associated with greater incidence of EONS in preterm infants.

Mean platelet volume and immature platelet fraction as predictors of early onset neonatal sepsis risk in neonates of 28-36 weeks gestational age

Background Early onset neonatal sepsis is a potential life-threatening problem for preterm infant. Diagnosing early onset neonatal sepsis is challenging. Difficulties in establishing diagnosis might cause delay definitive treatment.
 Objective To analyze for potential associations between early onset neonatal sepsis (EONS) risk and mean platelet volume (MPV) as well as immature platelet fraction (IPF) in neonates of 28-36 weeks gestational age.
 Methods A prospective cohort study was conducted at Dr. Hasan Sadikin General Hospital, Bandung, West Java. Mean platelet volume (MPV) and IPF were evaluated in the first ?6 hours of life and during the 48-72 hours after the first examination. This examination was followed by observation for sepsis development. Double logistic regression analysis was used.
 Results Of 115 subjects, 45 preterm infants (39.1%) developed early onset neonatal sepsis. The increase in both mean MPV and mean IPF were significantly different (P<0.05). Double logistic regression analysis revealed that an increase in mean MPV (ORadj=6.14; 95%CI 1.99 to 18.96; P=0.002) and mean IPF (ORadj=6.56; 95%CI 2.64 to 16.34; P<0.001) were significantly associated with increased risk of sepsis.
 Conclusion The MPV and IPF increase are associated with greater incidence of EONS in preterm infants.

Immature Platelet Fraction: Its Clinical Utility in Thrombocytopenia Patients

Objectives Etiology of thrombocytopenia is multifactorial and its pathogenesis should be distinguished for appropriate management. Newly formed immature platelets are called reticulated platelets (RPs) and can be estimated in peripheral blood using automated hematology analyzers, which express them as immature platelet fraction (IPF). In the present study we intend to assess and establish the clinical utility of IPF in differentiating the two major causes of thrombocytopenia—decreased production and increased destruction of platelets—along with determining its significance in monitoring patients with thrombocytopenia. Materials and Methods Sixty-one cases of thrombocytopenia and 101 healthy controls with normal platelet count were included in the study. IPF and all the other usual blood cell parameters were measured using a fully automated hematology analyzer. Based on the pathogenesis of thrombocytopenia, the cases were divided into groups and the difference in IPF value between the groups was evaluated. Results The reference range of IPF among healthy controls was estimated to be 0.7 to 5.7%. The mean IPF was significantly higher in patients with increased peripheral destruction of platelets (13.4%) as compared to patients with decreased production of platelets (4.6%). The optimal cutoff value of IPF for differentiating patients with increased peripheral destruction of platelets from patients with decreased production of platelets was 5.95% with a sensitivity of 88% and specificity of 75.9%. Conclusion Measurement of IPF is useful for detecting evidence of increased platelet production and helps in the initial evaluation of thrombocytopenia patients. It is a novel diagnostic method which can be used to differentiate patients with thrombocytopenia due to increased destruction of platelets from patients with thrombocytopenia due to bone marrow failure/suppression.

Immature platelet fraction as a predictor of platelet count recovery following allogeneic bone marrow transplantation

The immature platelet fraction (IPF) is a marker of increased platelet production. An increase in IPF is associated with increased marrow production; therefore, a subsequent increase in a bone marrow transplant recipient during the pancytopenic phase may correlate with platelet recovery and engraftment. We performed a retrospective cohort study and evaluated 32 patients who underwent allogeneic bone marrow transplantation. Patients had platelet count, neutrophil count, platelet transfusion and IPF recorded over a period extending from stem cell infusion, day 0, to day 30. The outcomes analysed were platelet count versus time and IPF versus time to establish the predictive ability of the IPF to determine platelet count recovery. Further analysis was performed to confirm the strength of the correlation and the sensitivity of the IPF in predicting a platelet count greater than 50 at day 30. The IPF was shown to rise 5 days prior to platelet count increase. An IPF rise was also shown to correlate with higher average platelet counts at day 30 of transplant. The utility of the IPF in predicting a platelet count of over 50 at day 30 was strongest between days 11 and 15 with an area under the curve (AUC) of 0.79. An IPF of 2.0 or above had 69% sensitivity and 85% specificity for predicting a platelet count of greater than 50 by day 30. In allogeneic bone marrow transplantation, the IPF is a reliable predictor of platelet recovery. The mean IPF between day 11 and day 15 is the most sensitive in predicting a robust platelet count of greater than 50 by day 30.

Age-wise reference range of immature platelet fraction in neonates.

Immature platelet fraction (IPF) is a quantification of immature platelets in the circulation reflecting the state of thrombopoiesis in the marrow. Normal reference range for IPF has been established in adults. Reference intervals in neonates are highly dependent on gestational age of the neonate. Complete blood counts (CBC) with IPF of all neonates admitted in neonatal intensive care unit (NICU) were analyzed using Mindray BC-6800 Auto Hematology analyzer. Platelet count of less than 150 × 10^9/L was assigned as thrombocytopenia. Neonates were divided into four groups as per the corrected gestational age (CGA) on the day of CBC analysis: 28-32 weeks, 32-34 weeks, 34-37 weeks, and >37 weeks according to World Health Organization (WHO) classification. Mean, standard deviation, and 95% confidence interval for IPF was calculated in each group and reference range for IPF was derived. Mean IPF in neonates with normal platelet count was term--3.58 (95% CI 3.29 to 3.87), late preterm Neonates (34-37 weeks)--4.14 (95% CI 3.82 to 5.0), moderate preterm neonates (32-34 weeks)--4.14 (95% CI 3.46 to 4.82), and in Very Preterm neonates (28-32 weeks)--IPF of 5.51 (95% CI 3.95 to 7.07). We aimed to establish a reference range for IPF in neonates of different gestational age groups. The IPF values in neonates were comparable between hematology analyzers in neonates with normal platelet counts.

CLINICAL RELEVANCE OF EXTENDED PLATELET INDICES IN THE DIAGNOSIS OF IMMUNE THROMBOCYTOPENIA.

SUMMARYImmune thrombocytopenia (ITP) is an autoimmune disorder. Besides platelet count, immature platelet fraction (IPF) can be used as a tool to predict megakaryocytic activity in ITP patients. The aim of the study was to evaluate the utility of extended platelet indices in ITP diagnosis and their association with disease persistence and severity. This case-control study (1:1), conducted from January 2015 to December 2017, included 111 ITP patients and 111 healthy controls. ITP patients were grouped as newly diagnosed ITP, persistent ITP, chronic ITP, and refractory ITP patients. Peripheral blood was collected and complete blood profile parameters were recorded using Sysmex XN 1000. Significant (p≤0.05) difference between the groups of ITP patients and healthy control subjects was determined by Fisher exact test, while Pearson correlation was used to evaluate platelet count correlation with IPF using SPSS ver. 23. Low hemoglobin and platelet counts with high total leukocyte count and IPF were detected in ITP patients as compared to healthy subjects (p≤0.001). Among all groups of ITP patients, very low platelet count (6.9±6.02.x109/L) with highest mean IPF (27.1±19.2%) was observed in newly diagnosed ITP group. Other platelet parameters including mean platelet volume (MPV), plateletcrit, platelet large cell ratio (P-LCR) and platelet distribution width values were also altered in patient groups. Pearson correlation revealed negative relationship between platelet count and IPF in all patient groups. With the advent of new, sophisticated hematologic analyzers, the IPF and other platelet parameters provide simple, reliable and easier tools for predicting platelet disorders such as ITP, and to some extent the disease severity. Besides IPF, the MPV and P-LCR seemed to predict disease severity, treatment responsiveness, and duration of the disease to some extent.

Influence of antiretroviral therapy and cardiovascular disease on the immature platelet fraction in patients living with HIV

Cardiovascular disease is an important contributor to morbidity and mortality in people living with HIV . The immature platelet fraction (IPF) is increased in HIV-negative patients with cardiovascular disease and evidence suggests that an enlarged IPF is associated with adverse cardiovascular events. In this multi-center observational study, we aimed to investigate how the IPF in people living with HIV is influenced by antiretroviral therapy and cardiovascular disease. Subjects without cardiovascular disease that received antiretroviral therapy showed a smaller IPF accompanied by lower D-dimer and C-reactive protein (CRP) levels compared to therapy-naïve subjects (mean IPF: 2.9% vs. 3.9%, p = .016; median D-dimer: 252 µg/L vs. 623 µg/L, p < .001; median CRP: 0.2 mg/dL vs. 0.5 mg/dL, p = .004). No significant differences for the IPF, D-dimer or CRP were found between subjects on antiretroviral therapy with documented cardiovascular disease and therapy-naïve subjects. In conclusion, we observed a reduction in the IPF among subjects on therapy only in the absence of cardiovascular disease. In contrast, subjects receiving therapy that had documented cardiovascular disease showed an IPF comparable to therapy-naïve subjects. Future studies are needed to investigate if an enlarged IPF may serve as a biomarker in predicting adverse cardiovascular events in people living with HIV.

PB2372 THE CORRELATION AND PREDICTIVE VALUE OF IMMATURE PLATELET FRACTION TO PLASMA PLATELET RECOVERY IN PATIENTS RECEIVING AUTOLOGOUS STEM CELLS TRANSPLANTATION

Background: Engraftment is a critical milestone of the hematopoietic stem cell transplantation process. The immature platelet fraction (IPF) are considered early indicators of bone marrow recovery. Aims: The objective of this study was to assess this parameter as predictors of autologous stem cell transplantation. Methods: The cross-sectional study was conducted at Ampang Hospital from June 2016 to January 2019, and included 30 autologous transplant patients with various hematologic malignancies. The results of post-transplant IPF and PLT were traced from the hematology laboratory, and validated by a hematologist before analysis. The role of IPF towards post-transplant PLT recovery was investigated by using parameters such as transient increase in IPF (%), time to transient increase in IPF (days), and 7 days mean IPF (%), towards PLT engraftment (days), lowest PLT, time to lowest PLT (days), PLT recovery (%), and PLT recovery time (days) from transplant day and lowest PLT. The degree of correlation was determined based on the Cohen's convention (1988). Patients with incomplete results (more than 50% missing data) were excluded from the analysis. Results: The median age of the cohort was 37 years, ranging from 18 to 67 years. The conditioning regimens used for autologous transplant included BEAM (69.6%), high dose melphalan (21.7%) and Bu/TT/Cy (8.7%). The mean of PLT engraftment was 11.4, ranging from 10.7 – 12.0 days after autologous transplantation. The cohort presented a mean value of 5.43% for transient increase in IPF, 4.7 days for time to transient increase in IPF, and 3.67% for 7 days IPF. The mean values in relation to PLT recovery were 14.40 × 109/L for lowest PLT, 5.3 days for time to lowest PLT, 225% for PLT recovery, and 6.9 days for PLT recovery time from transplant day and 1.7 days for PLT recovery time from lowest PLT. Statistically significant and positive correlations were found in the transient increase in IPF towards the PLT recovery time from the lowest PLT achieved in transplant patients (r = 0.6141, p = 0.0114); in the transient increase in IPF towards the PLT recovery time from transplant day (r = 0.6028, p = 0.0135); in post-transplant 7 days mean IPF towards the PLT recovery time from the lowest PLT achieved in transplant patients (r = 0.7450, p = 0.0014). A negative correlation was found in the time to the transient increase in IPF towards the PLT recovery time from the lowest PLT (r = –0.5245,p = 0.0370). The degree of the above correlations were considered strong (|r| > 0.5). Summary/Conclusion: The generation and release of IPF, as part of hematopoietic activity seemed to be predictive and correlated with the PLT recovery time. A transient increase in the IPF preceded the PLT recovery by approximately 2 days and may be used to predict PLT recovery in patients receiving autologous transplantation. The longest time to have a transient increase in the IPF, the shortest time required for PLT to bounced back from its lowest level.

Stromal cell-derived factor-1 rs2297630 polymorphism associated with platelet production and treatment response in Chinese patients with chronic immune thrombocytopenia

Stromal cell-derived factor-1 (SDF-1), signaling through CXCR4, is implicated in megakaryopoiesis and platelet production. SDF-1 rs2297630 is a functional polymorphism in linkage disequilibrium with other functional variants in SDF-1. This study aimed to investigate the role of SDF-1 rs2297630 in chronic ITP. The genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism and confirmed by direct sequencing. Immature platelet fraction (IPF) was performed using Sysmex XE-2100. Anti-platelet autoantibodies were assayed by enzyme-linked immunosorbent assay. The main characteristics at diagnosis and the outcome of chronic ITP in 201 Chinese patients were retrospectively reviewed. There was no significant difference in either genotype or allelic distribution between ITP patients and the controls (p = 0.114; p = 0.787). However, both heterozygote (GA) and homozygote minor allele (AA) patients had significantly increased megakaryocyte quantity compared to homozygote genotype (GG) patients at diagnosis (p = 0.011). The mean IPF values of GA and AA genotype patients were higher than those observed in the GG genotype patients when platelet counts ≤50 × 109/L at diagnosis (p = 0.007). Patients with GA and AA genotype showed a higher response rate to standard treatments than patients with GG genotype (p < 0.001). In particular, GA and AA genotype patients had a significantly increased chance of responding to steroids, intravenous immunoglobulin (IVIG), and thrombopoietin analogs (p = 0.007; p = 0.029; p = 0.034, respectively). No significant difference was found between anti-platelet antibodies and genotypes (p = 0.296). In summary, the SDF-1 rs2297630 was associated with platelet production and treatment response in Chinese patients with chronic ITP.

Immature Platelet Fraction Predicts Outcome and Sepsis Development in Critically Ill Patients Admitted to a General Intensive Care Unit, but Not in Neutropenic Patients

Introduction: Immature platelet fraction (IPF) is a new laboratory parameter, representing a fraction of young platelets in peripheral blood count which is known to correlate with thrombopoiesis. IPF can be reported in absolute numbers or expressed as percentage (IPF%) of total platelet count. IPF% can be used to differentiate individuals at higher risk for bleeding among patients suffering from immune thrombocytopenia and to predict recovery of blood counts after stem cell transplantation (SCT). Moreover, IPF% was also reported to predict the development of sepsis in patients admitted to the general intensive care unit. This study was aimed to prospectively evaluate the value of IPF% as a predictor of clinical outcome and/or mortality in patients susceptible to sepsis.Methods: Two different patient populations at high risk for life-threatening infection, i.e., patients presenting with fever and neutropenia and adults admitted to the general intensive care unit (ICU) of a tertiary health care center for various reasons apart from neutropenic fever were prospectively studied. IPF was measured using the Sysmex XE-2100 analyzer during the first 24 hours of hospitalization. In addition, C-reactive protein (CRP) and Interleukin-6 (IL-6) levels were tested in some of the patients. All patients were monitored and their vital signs, renal function, hemodynamic and respiratory state, as well as final outcome were recorded. For patients with neutropenic fever, the infectious pathogen was listed, whenever identified. Treating physicians were blinded to IPF% results to ensure that clinical decisions were not affected by consideration of this parameter.Results: One hundred and four adults with neutropenic fever and 138 additional adults admitted to the ICU were included in the study.A median age of patients admitted to ICU and those with neutropenic fever was 53 (range 17-88) and 55 (range 18-85) years; males composed 58% and 60% of the cohorts, respectively. A mean IPF% in patients admitted to ICU was significantly higher than that determined in neutropenic patients (8.6 vs 6.8). IPF% levels during the first 24 hours of admission, predicted mortality (p = 0.037) for patients admitted to ICU but not for patients presenting with neutropenic fever. In patients admitted to ICU, high IPF% was also associated with length of stay in the unit, poor hemodynamic status, and death. Neither IL-6 plasma level nor CRP correlated with these clinical outcomes. APACHE-II score (a known disease severity scale in ICU patients) and IPF% were not correlated by Pearson test (p=0.09).Conclusion: IPF% is a valuable biomarker for predicting prognosis in ICU patients independent of APACHE-II score. This study suggests that the validity of IPF% as a predictor of outcome depends on the bone marrow (BM) capacity. In patients with normal bone marrow admitted to ICU, IPF% correlates with the significance of stress and severity of the disease. In patients presenting with neutropenic fever, BM reserve is impaired due to chemotherapy. Larger studies are needed to evaluate the role of IPF% in different patient populations and to determine its application to patients with impaired BM reserves such as immunocompromised patients and those at older age. DisclosuresNo relevant conflicts of interest to declare.

750 Determining the Mean Cord Blood Immature Platelet Fraction (IPF) of Healthy Newborns

Thrombocytopenia is the most common hematologic abnormality in newborn infants Immature platelet fraction (IPF) shows megakaryopoetic activity. The purpose of this study is to provide non-invasive new approach to thrombocytopenic...

The Abrogated Thrombopoietin (TPO) Signal Transduction In Pediatric Patients Suffering From Thrombocytopenia-Absent Radii Syndrome Is Restored In Adult Patients, Suggesting An Additional, c-Mpl-Jak2-Independent Mechanism for Platelet Biogenesis.

AbstractAbstract 1561Thrombocytopenia-absent radii syndrome (TARS) is a rare congenital disorder defined by low platelet count and bilaterial aplasia of radii. Additionally, patients have perinatal eosinophilia and leukocytosis and are often anemic during the first years of life. At this time, a moderate, but enigmatic increase in platelet counts has been described, but patients remain thrombocytopenic and eventually continue to suffer from severe episodes of bleeding. Megakaryocytes, the immediate precursor cells of platelets, are scarce in the bone marrow and precursor cells fail to produce megakaryocytic colonies in response to thrombopoietin (TPO). Recently, we demonstrated that all TARS patients harbor a microdeletion on chromosome 1q21 which spans 120–200 kb, comprising 12–18 annotated genes. The deletion is also present in some unaffected parents (carriers) indicating that it is essential but not sufficient for generating the TARS phenotype.We analyzed 158 platelet counts of 33 patients over time and found that platelets increase within 2 years of life in most of our patients, but even in adult patients counts do not reach the lower norm. Thus, we performed an extended analysis of TPO signal transduction in platelets from 20 TARS patients. Overall, Jak2 kinase - despite being expressed in comparable amount - does not become phosphorylated in response to TPO when patients were below age 20, confirming our previous results also performed on young patients. Intriguingly, in platelets isolated from patients over age 20, Jak2 did become phosphorylated. As TPO activates several distinct pathways, we looked for the consequences of this bipartite TPO-responsiveness, including the activation of the alternate januskinase Tyk2, the STAT, the MAPK/ERK, and the Akt pathways. As expected, when Jak2 was not phosphorylated, Tyk2 and all downstream pathways were inactive. In contrast, in the presence of phosphorylated Jak2 (pJak2), all downstream pathways were activated, emphasizing the key role of Jak2 for TPO responsiveness. Platelets from either 20 healthy children or 11 carriers showed normal TPO signaling, excluding that the effect was due to a general age-dependence or a mere consequence of the microdeletion. Densitometric analyses confirmed our overall visual results. Expression levels of the TPO-receptor c-Mpl was not altered in 2 young and 2 adult patients compared to carriers, healthy children and adult controls, arguing against a compensatory upregulation in older patients. Furthermore, we sequenced all coding regions of Jak2 mRNA derived from patient-derived lymphoblastic cell lines (LCL) of one young and one adult patient and could not find any mutations. As bone marrow biopsies are typically not performed, changes in bone marrow cellularity or composition are not directly accessible. Recently, the immature platelet fraction (IPF) has been considered a surrogate marker for megakaryopoiesis. Interestingly, while there was no correlation between platelet count and IPF in 16 patients with TARS, we found a negative correlation between IPF with age. In 9 pediatric patients IPF was elevated (4.6%) compared to the median of 100 pediatric controls (2.7%), while in 7 adult TARS patients the mean IPF was 2.4%. These data provide circumstantial evidence that changes in megakaryopoiesis might drive the change in platelet biogenesis and TPO signaling. Plasma levels of stromal derived factor 1, a chemokine that contributes to restore platelet production in the absence of functional TPO signaling, were within the normal range in 6 patients with TARS. Real-time analysis of mRNA expression in LCL of genes within the microdeleted region indicates comparable expression in 2 unaffected parents with 2 controls, while 3 patients and 2 carriers showed the expected reduced expression. This includes the expression of PIAS3, a negative regulator of the Jak-STAT pathway. PIAS3 protein level, however, was normal in platelet lysates of TARS patients, making a key function for thrombocytopenia in TARS unlikely.Taken together, our data show an unexpected age-dependent change in TPO-signaling in platelets of TARS patients. As this change occurs much later than the amelioration of platelet counts, we suggest that an unknown factor influences platelet biogenesis during childhood. Disclosures:No relevant conflicts of interest to declare.

Estimating platelet production in patients with HIV‐related thrombocytopenia using the immature platelet fraction

Thrombocytopenia is common in patients with HIV infection. However, given the number of potential etiologies of low-platelet counts in this patient population, it is often difficult to determine the underlying cause. The immature platelet fraction (IPF) measures the number of reticulated platelets in peripheral blood and can be used to help determine if thrombocytopenia is secondary to low-platelet production or increased platelet turnover. We studied the performance characteristics of the IPF% in 50 inpatients with HIV-related thrombocytopenia and compared the results with 34 inpatients with HIV and normal platelet counts. The mean IPF% in the HIV thrombocytopenic group was 10.2% as compared with 6.8% in the HIV normal platelet count group (P = 0.001) and 3.1% in historical non-HIV controls (P < 0.001). In multivariate analyses, the presence of ITP, active infection, log CD4 count, platelet count, and diabetes mellitus were significantly associated with a higher IPF%. These findings suggest that increased platelet turnover plays an important role in the pathogenesis of HIV thrombocytopenia. Platelet turnover is also increased in patients with HIV in general, even when overt thrombocytopenia is absent.

Fluctuations in thrombopoietin, immature platelet fraction, and glycocalicin levels in a patient with cyclic thrombocytopenia

Cyclic thrombocytopenia (CT) is an uncommon disorder characterized by periodic fluctuations in platelet count, resulting in alternating episodes of thrombocytopenia and normal platelet counts. Its pathogenesis remains unclear. Here, we report the case of a 65-year-old man with CT who was initially diagnosed with idiopathic thrombocytopenic purpura (ITP) concomitant with chronic thyroiditis. ITP was diagnosed 12 years ago in the absence of periodic fluctuations in platelet counts. He had been treated with corticosteroids; underwent splenectomy; and subsequently been treated with azathioprine, vincristine, high doses of dexamethasone, and herbal medicine. He had not received antibiotic eradication therapy for Helicobacter pylori because there was no evidence of infection with this organism. Since his symptoms did not improve, the treatments were discontinued, and he was placed under observation. He complained of mild bleeding symptoms, such as petechiae and purpura, which occurred intermittently for several months before he presented to us to undergo detailed investigations. His platelet count varied between 3 9 10/ll and 30 9 10/ll approximately every 3–4 weeks. His white blood cell count and hemoglobin concentration remained unchanged. To elucidate the mechanism underlying this disease, we evaluated the serum thrombopoietin (TPO) level, immature platelet fraction (IPF), plasma glycocalicin index normalized for the individual platelet count (GCI), and T helper (Th)1/Th2 ratio. The serum TPO level was measured with a human TPO ELISA kit (R&D Systems Inc., Minneapolis, MN, USA). The serum levels of TPO, a principal regulator of megakaryogenesis and thrombopoiesis, are thought to be regulated via receptor-mediated clearance by platelets and megakaryocytes. The median serum TPO concentration in healthy individuals is 51 pg/ml. The plasma glycocalicin level was measured with a Glycocalicin EIA kit (Takara Bio Inc., Ohtsu, Japan). The GCI was calculated as proposed by Steinberg et al. [1]: GCI = glycocalicin level 9 250 9 10/individual platelet count (/ll). Glycocalicin is a proteolytic fragment of the a-chain of glycoprotein Ib, a platelet membrane. The GCI reflects the rate of platelet destruction [2]. The mean GCI in healthy individuals is 1.27 (range 0.87–1.77). The IPF was determined to reliably quantify reticulated platelet counts by using a fully automated hematology analyzer XE-2100 equipped with special software IPF Master (Sysmex, Kobe, Japan). Reticulated platelets are RNA-rich immature platelets and are thought to reflect the ability of the bone marrow to produce platelets. Therefore, the IPF, as a surrogate marker of the reticulated platelet count, reflects the rate of thrombopoiesis [3]. The mean IPF in healthy individuals is 2.0% (range 0.5–5.7%). The Th1/Th2 ratio was determined by using flow cytometry analysis to measure the ratio of CD4? cells containing intracellular interferon-c to those containing interleukin-4. The fluctuations in the TPO levels, percentage of IPF, and GCI were synchronous and inversely proportional to those in the platelet counts (Fig. 1). In the thrombocytopenic phase, elevated GCI indicated platelet destruction in this patient. Thrombopoiesis was simultaneously accelerated in response to TPO. Consequently, the IPF, which is as an indicator of thrombopoiesis, increased. In the present case, CT seemed to be closely associated with cyclic increases in platelet destruction. However, the mechanism of cyclic platelet destruction remains to be elucidated. Th1/Th2 balance is T. Yujiri (&) Y. Tanaka M. Tanaka Y. Tanizawa Third Department of Internal Medicine, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan e-mail: yujirit@yamaguchi-u.ac.jp

Immature platelet fraction (IPF) in hospitalized patients with neutrophilia and suspected bacterial infection

Neutrophilia is frequently in hospitalized patients, so a screening test for infections would be very useful. The immature platelet fraction (IPF) is provided by the automated blood analyzer XE 2100 (Sysmex, Kobe, Japan) as a proportional value of the total optical platelet count [IPF%; an absolute count of immature platelets can also be obtained (AIPC)] to indicate the rate of platelet production. IPF could help to identify the aetiology of thrombocytopenia and to recognize the increased bone marrow activity as occurred during the course of infectious disease. We selected from daily routine cell blood counts 535 samples from adult patients (age >14 years) with neutrophilia (> 8 x 10(9)/L) and platelets > or =150 x 10(9)/L, to avoid bias due to physiological increase of IPF. In 153 patients blood cultures (BC) were done the same day of IPF determination because of clinically suspected infection (fever > or =38 degrees C). Eighty-nine samples (58.2%) had positive BC (75 Gram-positive agents, 14 Gram-negative). Using our IPF reference normal range [IPF% 2.39% (0.8-5.1); AIPC 5.15 x 10(9)/L (2-12.6)], we found a significantly (p<0.0001) higher level of IPF in samples with positive BC [mean IPF% 4.86+/-2.67%, median 3.8 (range 2.4-15.8); mean AIPC 14.74+/-9.26 x 10(9)/L, median 11.7, (range 4.7-44.9)] than in BC negative samples [mean IPF% 1.79+/-0.63%, median 1.7 (range 0.5-4.7); mean AIPC 6.55+/-3.58 x 10(9)/L, median 5.45 (range 1.6-20.4)]. The increased IPF shows a statistically significant correlation with BC positivity. This parameter could therefore be used in the daily laboratory routine in patients with neutrophilia as a low cost screening test for bacterial infection.

Immature platelet fraction as novel laboratory parameter predicting the course of neonatal thrombocytopenia

Immature platelet fraction as novel laboratory parameter predicting the course of neonatal thrombocytopenia

The Immature Platelet Fraction in HIV Patients with Thrombocytopenia.

Thrombocytopenia is a common clinical feature of HIV infection. Given the number of possible etiologies of thrombocytopenia in a patient with known HIV, a peripheral blood test effective in determining the likely pathophysiologic basis of the thrombocytopenia would be a valuable clinical tool. Immature platelets are released early from the bone marrow in response to increased platelet turnover. These platelets contain residual megakaryocyte mRNA and have been termed reticulated platelets. A new assay, the Immature Platelet Fraction (IPF), measures the reticulated platelet count in peripheral blood. Patients with increased destruction of platelets from such conditions as ITP consistently have a higher IPF percent, while patients with decreased platelet production have a low or normal IPF percent. The goal of our study was to determine the performance characteristics of the IPF assay in HIV patients with thrombocytopenia and to see if the IPF percent could be used to help elucidate the etiology of low platelet counts in this group of patients. All adult patients admitted to the Johns Hopkins Hospital with a diagnosis of HIV and a platelet count less than 150,000 were eligible for enrollment. 62 patients were identified from February 2007 to June 2007. 34 control samples were obtained from inpatients with HIV who were not thrombocytopenic. In addition, 81 samples were available from non-HIV historical controls with normal platelet counts. The mean platelet count in the HIV thrombocytopenic group was 92,000 while the mean platelet count in the HIV control group was 254,000 (p value <.001). The mean platelet count in the non-HIV historical control group was 274 (p=.34 when compared to the HIV control group). The mean IPF percent in the HIV thrombocytopenic group was 10.2% as compared to 6.8% in the HIV control group (p=.001). The mean IPF in historical non-HIV controls was 3.1% (p<.001 for both the HIV thrombocytopenic and the HIV control group). Univariate analyses were conducted to identify potential individual predictors of a high IPF percent. Backward selection was then performed using multivariate linear models with a threshold Wald test p-value of 0.05. ITP, diabetes mellitus and cirrhosis were significantly associated with a higher IPF percent with a co-efficient (95% confidence interval) of 6.98 (3.05–10.91), 4.73 (1.39–8.06), and 14.18 (9.7–18.66), respectively. CD4 count, HIV viral load, hepatitis C and reticulocyte count were not correlated with IPF percent. Our results suggest that patients with HIV have increased platelet turnover as compared to patients without HIV. Thrombocytopenic patients with HIV have increased platelet turnover relative to both non-thrombocytopenic HIV patients and to historical non-HIV controls. History of ITP, diabetes mellitus, and cirrhosis are predictive of an elevated IPF percent. Reticulocyte count is not correlated to IPF percent, suggesting that a low reticulocyte count is not a reliable marker for decreased bone marrow production in HIV thrombocytopenia. It is unlikely that the IPF assay alone can be used to determine the pathophysiologic basis of thrombocytopenia in any single patient with HIV. Further work needs to be done to clarify the utility of the IPF assay in this group of patients.

An Increase in the Immature Platelet Fraction Predicts Reconstitution of the Platelet Count and May Reduce Prophylactic Platelet Transfusions after Stem Cell Transplantation.

A new automated method to reliably quantitate reticulated platelets, expressed as the immature platelet fraction (IPF), has been developed on an automated cell counter (XE-2100, Sysmex). The IPF is identified by flow cytometery using a polymethine dye, staining platelet RNA, in the reticulocyte channel; the results are available at the same time as the CBC. The IPF normal range is 1.1–6.1%, mean 3.4%, 2 SD 2.3%. Reproducibility and stability results over 48 hours were acceptable. The IPF is raised when there is increased peripheral consumption/destruction. In untreated idopathic thrombocytopenic purpura, n = 12, mean 22.3%, range 9.2–33.1% and active thrombotic thrombocytopenic purpura, n = 5, mean 17.2%, range 11.2–30.9%. Patients who may require prophylactic platelet transfusion, usually at threshold counts less than 10 x 109/L, to support periods of marrow aplasia were monitored daily for platelet count and IPF%. The recovery phase of thrombocytopenia in most chemotherapy (n=13) and stem cell/bone marrow transplant patients (n=15) was preceded by a rise in IPF% several days prior to platelet recovery, mean IPF 13.7%, range 7–27.3%. In particular, patients undergoing autologous transplantation (n=8) using peripherally collected stem cells have a very characteristic IPF% motif, with a rise 1 day prior to engraftment for all patients except one where it was 2 days prior. For bone marrow derived transplant patients the increase in IPF was more variable, the rise preceded the rise in platelet count by 2–7days. These patients suffer more septic episodes where there is a rise in the IPF with no immediate increase in the platelet count, and require more regular platelet transfusions. Following a platelet transfusion there is a 24-hour transitory fall in the IPF response, which may impede platelet recovery. A parameter that could predict the timing of platelet recovery could be used clinically to reduce the use of prophylactic platelet transfusion in these patients, thus minimising donor exposure, infection risk and allowing substantial financial savings. The IPF is a useful parameter in the evaluation of the thrombocytopenic patient and has the potential to allow more optimal transfusion of platelet concentrates.