Prognostic value of immature platelet fraction and plasma thrombopoietin in disseminated intravascular coagulation

Reference guide for the diagnosis of adult primary immune thrombocytopenia, 2023 edition

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Diagnosis of ITP is still challenging because ITP has been diagnosed by exclusion. Exclusion of thrombocytopenia due to bone marrow failure is especially important in Japan because of high prevalence of aplastic anemia compared to Western countries. Hence, we propose a new diagnostic criteria involving the measurement of plasma thrombopoietin (TPO) levels and percentage of immature platelet fraction (RP% or IPF%); 1) isolated thrombocytopenia with no morphological evidence of dysplasia in any blood cell type in a blood smear, 2) normal or slightly increased plasma TPO level (< cutoff), 3) elevated RP% or IPF% (> upper limit of normal), and 4) absence of other conditions that potentially cause thrombocytopenia including secondary ITP. A diagnosis of ITP is made if conditions 1-4 are all met. Cases in which criterion 2 or 3 is not met or unavailable are defined as "possible ITP," and diagnosis of ITP can be made mainly by typical clinical course. These new criteria enable us to clearly differentiate ITP from aplastic anemia and other forms of hypoplastic thrombocytopenia and can be highly useful in clinical practice for avoiding unnecessary bone marrow examination as well as for appropriate selection of treatments.

Routine and Advanced Laboratory Tests for Hemostasis Disorders in COVID-19 Patients: A Prospective Cohort Study

BACKGROUND

Thrombosis is frequent during COVID-19 disease, and thus, identifying predictive factors of hemostasis associated with a poor prognosis is of interest. The objective was to explore coagulation disorders as early predictors of worsening critical conditions in the intensive care unit (ICU) using routine and more advanced explorations.

MATERIALS

Blood samples within 24 h of ICU admission for viscoelastic point-of-care testing, (VET), advanced laboratory tests: absolute immature platelet count (A-IPC), von Willebrand-GPIb activity (vWF-GpIb), prothrombin fragments 1 + 2 (F1 + 2), and the thrombin generation assay (TGA) were used. An association with worse outcomes was explored using univariable and multivariable analyses. Worsening was defined as death or the need for organ support.

RESULTS

An amount of 85 patients with 33 in critical condition were included. A-IPC were lower in worsening patients (9.6 [6.4-12.5] vs. 12.3 [8.3-20.7], p = 0.02) while fibrinogen (6.9 [6.1-7.7] vs. 6.2 [5.4-6.9], p = 0.03), vWF-GpIb (286 [265-389] vs. 268 [216-326], p = 0.03) and F1 + 2 (226 [151-578] vs. 155 [129-248], p = 0.01) were higher. There was no difference observed for D-dimer, TGA or VET. SAPS-II and A-IPC were independently associated with worsening (OR = 1.11 [1.06-1.17] and OR = 0.47 [0.25-0.76] respectively). The association of a SAPS-II ≥ 33 and an A-IPC ≤ 12.6 G/L predicted the worsening of patients (sensitivity 58%, specificity 89%).

CONCLUSIONS

Immature platelets are early predictors of worsening in severe COVID-19 patients, suggesting a key role of thrombopoiesis in the adaption of an organism to SARS-CoV-2 infection.

Autoimmune-mediated thrombocytopenia after allogeneic hematopoietic stem cell transplantation: significance of detecting reticulated platelets and glycoprotein-specific platelet autoantibodies

Autoimmune hematological disorders are rare complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Diagnosis of immune thrombocytopenia (ITP) is challenging, especially after allo-HSCT, because various complications such as graft-versus-host disease, disease relapse, viral infection, thrombotic microangiopathy, and drug side effects can also cause thrombocytopenia. Assessment of reticulated platelets (RP) and plasma thrombopoietin (TPO) levels may be useful to distinguish between ITP and hypoplastic thrombocytopenia. ITP is generally characterized by an increased percentage of RP, and a normal or slightly increased plasma TPO level. We now report three cases of thrombocytopenia after allo-HSCT. RP% was elevated in these patients, as it is in primary ITP. However, in contrast to primary ITP, plasma TPO levels were high in two of three patients. Anti-αIIbβ3 and anti-GPIb/IX-specific direct IgG antibodies were detected as well, suggesting occurrence of immune-mediated platelet destruction in addition to bone marrow suppression in two patients. All three patients were successfully treated with corticosteroids and/or thrombopoietin receptor agonists (TPO-RAs). These results suggest that increased RP% and detection of glycoprotein-specific platelet autoantibodies are useful for the diagnosis of ITP after HSCT.

Can immature platelet fraction be an early predictor for congenital pneumonia?

Aim:

Timely diagnosis and treatment of congenital pneumonia are crucial. A new hematologic parameter, immature platelet fraction, has been used to gather clinical information on the prognosis of thrombocytopenia, as well as to measure inflammatory activity in adult patients. This study aimed to compare immature platelet fraction and sepsis biomarkers in late-preterm infants diagnosed as having congenital pneumonia and to evaluate its predictive value for congenital pneumonia.

Material and Methods:

Late-preterms were categorized based on infectious vs. non-infectious etiology of respiratory distress. Two sets of blood samples for markers were taken at 12–24 (sample-1) and 48–72 hours (sample-2) after birth. Immature platelet fraction was measured using a Sysmex XN-3000 analyzer.

Results:

From a total of 30 non-thrombocytopenic late-preterms, 16 were included in the congenital pneumonia group and 14 comprised the transient tachypnea group. The groups were comparable in terms of gestational age, birth weight, and cesarean section rate. The proportion of prolonged membrane rupture was significantly higher in the congenital pneumonia group. Values of immature platelet fraction-1, immature platelet fraction-2, and procalcitonin-2 were significantly higher in the congenital pneumonia group than in the transient tachypnea group. No significant differences were found between the groups in other biomarkers. It was determined that an immature platelet fraction-1 cut-off value of 2.9% could predict congenital pneumonia with a sensitivity of 65%, a specificity of 71.4%, a positive predictive value of 70.5%, and negative predictive value of 63.7% (area under the curve=0.724; p=0.028).

Conclusion:

Immature platelet fraction may have an early predictive role in the diagnosis of congenital pneumonia.

Pretreatment Immature Platelet Fraction as a Surrogate of Reticulated Platelets Predicts the Response to Corticosteroids in Adults with Immune Thrombocytopenia

OBJECTIVES

Reticulated platelets circulating in the blood reflect megakaryopoietic activity and platelet turnover and can be automatically and low-invasively measured as the immature platelet fraction (IPF) using a Sysmex XN hematocytometer. The present study retrospectively investigated whether or not the IPF can predict the treatment response to corticosteroids in adult patients with primary immune thrombocytopenia (ITP).

METHODS

Forty-six patients who had been newly diagnosed with primary treatment-naïve ITP and started treatment with corticosteroids were analyzed.

RESULTS

Among the 46 primary ITP patients, 33 (72%) responded to the treatment and 13 (28%) did not. The percentage of IPF (IPF%) among the nonresponders was significantly lower than that of the responders (6.6 vs. 16.0%; p < 0.001). In the receiver operating characteristics analysis, the optimum IPF% cut-off value for predicting the treatment response was 12%, with a specificity of 85% and a sensitivity of 76%.

CONCLUSIONS

Our findings thus suggest that measuring the IPF% as a surrogate of reticulated platelets is useful to identify patients likely to respond to corticosteroids.

Immature platelets: a review of the available evidence

Immature platelets or reticulated platelets are newly released thrombocytes. They can be identified by their large size and high RNA cytoplasm concentration. Immature platelet fraction (IPF) represents the percentage of immature circulative platelets to the total number of platelets. The development of analytical standardization of this hematological parameter by new automated devices allowed a better exploration of its contribution in a context of thrombocytopenia. In fact, several studies had confirmed its clinical utility to differentiate immune thrombocytopenia from other causes of thrombocytopenia. IPF can also predict platelets recovery after chemotherapy and successful engraftment. In addition, immature platelets have shown utility in other diseases such as coronary artery diseases, bacterial infections and liver diseases. Despite all these advantages, immature platelet fraction can be increased in some cases of thrombocytopenia characterized by platelets hypoproduction. The aim of this review is to present the immature platelet fraction contribution in clinical practice.

Reticulated platelets – clinical application and future perspectives

Reticulated platelets are immature platelets freshly released from the bone marrow into the circulation and contain vestigial amounts of ribonucleic acid. Thus, they can serve as an indicator for the activity of thrombopoiesis. Despite the current lack of a standardized reference method, two types of hematology analyzers have incorporated a fully automated measurement of reticulated platelets. The “immature platelet fraction” (IPF; Sysmex XE-/XN-series) has some clinical utility in the differential diagnosis of thrombocytopenia. This is less clear for “reticulated platelets” (retPLT; Abbott CELL-DYN Sapphire/Alinity HQ). The usefulness of these parameters in the prediction of platelet recovery after chemotherapy or stem cell transplantation and as a decision aid for platelet transfusions has not been unequivocally confirmed. Recent findings have shown an association of reticulated platelets with an adverse risk in patients with coronary artery disease and stroke as well as resistance to anti-platelet therapy. Furthermore, a role of reticulated platelets for the prediction of sepsis was indicated. However, validation in larger prospective trials is necessary to establish the clinical benefit of reticulated platelets in these conditions. This review gives an overview of the available analytical methods and summarizes the current knowledge regarding the clinical application of reticulated platelets.

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.

Clinical utility of mean platelet volume and immature platelet fraction in acute coronary syndrome

Background

Platelets play an important role in the pathogenesis of acute coronary syndrome (ACS). Patients with ACS have an increased mean platelet volume (MPV) and immature platelet fraction (IPF) resulting in elevation of thrombotic ability. In this study, we evaluated the diagnostic performance of MPV and IPF in identifying suspected ACS patients at emergency department. Moreover, we investigated the correlation between MPV or IPF with initial troponin I (TnI), one of the current ACS biomarkers.

Methods

This was a single-center study recruiting suspected ACS patients who had acute chest pain at the emergency department. Whole blood samples were obtained from all participants and MPV and IPF were measured by Sysmex XE-5000 hematology analyzer within 20 min of blood sampling. The diagnostic values of MPV and IPF in identifying ACS were analyzed retrospectively.

Result

In this study, 63 in 104 suspected ACS patients were diagnosed as ACS (65.3%). MPV and IPF were higher in ACS patients compared to non-ACS patients (MPV: 10.7 ± 0.80 fL vs 10.0 ± 0.64 fL, p < 0.001; IPF: 3.7 ± 2.64% vs 3.1 ± 2.69%, p = 0.030). MPV and IPF were similar in unstable angina and acute myocardial infarction patients. We showed that elevation of MPV could be an independent predictive factor of ACS (odds ratio: 5.038). At the optimal cut-off value of 10.55 fL (AUC 95% CI: 0.637–0.836), the diagnostic performance of MPV in predicting ACS had an area under a receiver operating characteristic curve (AUC) of 0.736 with sensitivity and specificity of 54.2% and 82.8%, respectively. Patients with both of initial TnI and MPV higher than the established cut-off value had increased incidence (3.792 fold) for ACS development compared to patients with TnI below the cut-off value. Furthermore, diagnosing ACS with both MPV and initial TnI increased the positive predictive value from 84.2% to 86.7%. No correlation was observed between MPV or IPF and the mortality rate of ACS patients (MPV: 3.8% vs 11.1%, p = 0.300; IPF: 12.0% vs 37.5%, p = 0.054).

Conclusion

Here we show that ACS patients have higher MPV and IPF compared to non-ACS patients. We further demonstrate that MPV can be utilized as an independent predictor for early diagnosis of low-risk ACS patients who have acute chest pain.

Immature platelet fraction in septic patients: clinical relevance of immature platelet fraction is limited to the sensitive and accurate discrimination of septic patients from non-septic patients, not to the discrimination of sepsis severity

Background

The immature platelet fraction (IPF) reflects the degree of reticulated platelets. We evaluated performances of IPF as a biomarker for the discrimination of septic patients from non-septic patients and sepsis severity.

Methods

Total 312 patients admitted between March and July 2013 were enrolled and samples were obtained at admission. Lactate (LA), procalcitonin (PCT), C-reactive protein (CRP), immature granulocyte fraction (IG), immature reticulocyte fraction (IRF), and IPF were analyzed as sepsis biomarkers and their performances were compared.

Results

The performance of IPF (area under the curve [AUC]=0.868) in the discrimination of septic patients from non-septic patients was comparable to PCT/CRP/LA/IG (AUC=0.923/0.940/0.781/0.812, P=0.233/0.106/0.186/0.353, respectively), and was significantly better than the IRF (AUC=0.658, P=0.007). Sensitivity (89.8%, 95% confidence interval [CI] 84.9-99.8%) and accuracy (83.2%, 95% CI 78.8-90.0%) of IPF were the best among all biomarkers. The performance of IPF in discriminating septic patients from non-septic patients with local infection showed similar results. However, the IPF could not efficiently discriminate sepsis severity (AUC=0.599), similar to other biomarkers (AUC=0.519-0.752).

Conclusions

The IPF possessed high sensitivity/accuracy in discriminating septic patients from non-septic patients, regardless of local infection status. However, the IPF did not efficiently discriminate sepsis severity. The clinical relevance of IPF as a sepsis biomarker is, therefore, limited to sensitive and accurate discrimination of septic patients from non-septic patients, not discrimination of sepsis severity.

Thrombopoietin as Early Biomarker of Disease Severity in Patients With Acute Pancreatitis

OBJECTIVES

To study the concentrations of thrombopoietin (TPO), a growth factor recently involved in the pathogenesis of experimental acute pancreatitis (AP), and its potential role as an early diagnostic and prognostic biomarker in patients with AP.

METHODS

Thrombopoietin was measured in 44 AP patients, 18 patients with nonpancreatic acute abdominal pain, and 18 healthy volunteers. Acute pancreatitis severity was classified on the basis of the 2012 International Atlanta Symposium on Acute Pancreatitis criteria.

RESULTS

Thrombopoietin levels did not differ between AP patients and control subjects, whereas these were higher in patients with moderately severe or severe AP compared with those with mild AP. Receiver operating characteristic curve analysis of TPO for severe AP diagnosis showed an area under the curve of 0.80. A cutoff value of 31.48 pg/mL showed the highest sensitivity, allowing to rule out severe AP when TPO was lower, whereas TPO higher than 98.23 pg/mL was associated with severe AP with high specificity (93.5%). Furthermore, TPO levels were greater in AP patients developing organ dysfunction or sepsis and in nonsurvivors compared with survivors.

CONCLUSIONS

Our data provide the first evidence for TPO as potential early prognostic biomarker in AP patients. High TPO levels at hospital admission may predict organ dysfunction, sepsis, and fatal outcome in AP patients.

Association of the immature platelet fraction with sepsis diagnosis and severity

Management of Sepsis would greatly benefit from the incorporation of simple and informative new biomarkers in clinical practice. Ideally, a sepsis biomarker should segregate infected from non-infected patients, provide information about prognosis and organ-specific damage, and be accessible to most healthcare services. The immature platelet fraction (IPF) and immature reticulocyte fraction (IRF) are new analytical parameters of the complete blood count, that have been studied as biomarkers of several inflammatory conditions. Recently, a study performed in critically-ill patients suggested that IPF could be a more accurate sepsis biomarker than C-reactive protein (CRP) and procalcitonin. In this retrospective study we evaluated the performance of IPF and IRF as biomarkers of sepsis diagnosis and severity. 41 patients admitted to two intensive care units were evaluated, 12 of which with severe sepsis or septic shock, and 11 with non-complicated sepsis. Significantly higher IPF levels were observed in patients with severe sepsis/septic shock. IPF correlated with sepsis severity scores and presented the highest diagnostic accuracy for the presence of sepsis of all studied clinical and laboratory parameters. No significant differences were observed in IRF levels. Our results suggest that IPF levels could be used as a biomarker of sepsis diagnosis and severity.

Presence of Antiheparin/Platelet Factor 4 Immunoglobulin G Is Associated With Poor Prognosis in Patients With Suspected Disseminated Intravascular Coagulation

The underlying inflammatory or infectious condition in disseminated intravascular coagulation (DIC) may stimulate the formation of antiheparin/platelet factor 4 (PF4) antibody, and the resulting antibody may affect the clinical course of DIC. We investigated the prognosis of antiheparin/PF4 antibodies in patients with suspected DIC. We measured heparin/PF4 immunoglobulin G (IgG) and total antibody levels using an automated chemiluminescence system in 118 patients with DIC. Of the 118 patients, 13 (11.0%) patients were positive for total antiheparin/PF4, and 6 (5.1%) patients were positive for antiheparin/PF4 IgG. These 13 patients were negative for platelet-activating antibody and had low-heparin-induced thrombocytopenia probability scores. Patients with antiheparin/PF4 IgG were older and had lower antithrombin levels than patients without antiheparin/PF4 IgG. Patients with antiheparin/PF4 IgG had a higher risk of mortality than those without antiheparin/PF4 IgG. The presence of antiheparin/PF4 IgG in old age or low antithrombin level patients with DIC with old age or low antithrombin level suggests a poor prognosis.

Renal artery thrombosis secondary to sepsis-induced disseminated intravascular coagulation in acute pyelonephritis

There are some reports of renal vein thrombosis associated with acute pyelonephritis, but a case of renal artery thrombosis in acute pyelonephritis has not been reported yet. Here we report a case of renal artery thrombosis which developed in a patient with acute pyelonephritis complicated with sepsis-induced disseminated intravascular coagulation (DIC). A 65-year-old woman with diabetes was diagnosed with acute pyelonephritis complicated with sepsis. Escherichia coli was isolated from both blood and urine cultures. When treated with antibiotics, her condition gradually improved. She suddenly complained of severe right flank pain without fever in the recovery phase. A computed tomography scan revealed right renal artery thrombosis with concomitant renal infarction. Prophylactic anticoagulation therapy was not suggested because of sustained thrombocytopenia and increased risk of bleeding. Flank pain resolved with conservative treatment and perfusion of infarcted kidney improved at the time of discharge. To our knowledge, this is the first case of renal artery thrombosis related to acute pyelonephritis with sepsis-induced DIC.