Immature platelet fraction based diagnostic predictive scoring model for immune thrombocytopenia

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.

Reticulated Platelet Count as a Diagnostic Tool in Immune Thrombocytopenia (ITP)

OBJECTIVE

This study aimed to compare the reticulated platelet count between patients having thrombocytopenia secondary to autoimmune destruction (immune thrombocytopenia {ITP}), bone marrow failure, and healthy controls who presented to a tertiary care hospital in Karachi, Pakistan.

METHODOLOGY

A cross-sectional study was conducted from February 2021 to October 2022 in the Department of Hematology, National Institute of Blood Disease (NIBD) Hospital in Karachi, Pakistan, that involved examining three groups: 30 patients with immune thrombocytopenia, 30 patients with thrombocytopenia secondary to reduced production from bone marrow, and 30 healthy controls. The study utilized the Sysmex XN-1000 (Hyogo, Japan: Sysmex Corporation) automated hematology analyzer to perform a complete blood count (CBC) test. Additionally, peripheral blood was stained with Leishman stain and examined under a microscope to eliminate pseudo thrombocytopenia and identify any abnormal cells or dysplasia. The immature platelet fraction (IPF) was then performed on Sysmex XN 1000 after ensuring adequate quality control. Finally, the data were analyzed using DATAtab (Graz, Austria: DATAtab) and SPSS version 25 (Armonk, NY: IBM Corp.).

RESULTS

Of the ninety participants, the median age was 33 years with a range of 18-71 years. Patients with ITP had a significantly higher median IPF% (median=26.65, IQR=15-39.4) than thrombocytopenia due to bone marrow failure (median=9.25, IQR=4.55-14.30) and healthy controls (median=7, IQR=4.40-9.90), with a p-value of 0.001. The immune thrombocytopenia group demonstrated an increase in IPF% as platelet counts increased, indicating a significant moderate correlation between IPF% and platelets in these patients (r=0.438, p=0.016) and confirming that IPF% was an independent predictor for the detection of ITP.

CONCLUSION

Reticulated platelet count may be a useful diagnostic tool to differentiate between ITP and thrombocytopenia caused by bone marrow failure. Because of its non-invasive nature, IPF is a valuable tool for expediting the management of thrombocytopenia associated with increased IPF.

Role of Long non Coding RNAs, NEAT1 and Lnc-DC Expression in Pediatric Immune Thrombocytopenic Purpura

Background

Pediatric immune thrombocytopenic purpura (ITP) is an autoimmune disease; whose etiology is unknown. lncRNAs are regulators of numerous actions, which participate in the development of autoimmune diseases. We evaluated the expression ofNEAT1 and Lnc-RNA in dendritic cell (Lnc-DC) in pediatric ITP.

Methods

Sixty ITP patients and 60 healthy subjects were enrolled in the present study; Real-time PCR was performed to assess the expression levels of NEAT1 and Lnc-DC in sera of children with ITP as well as healthy children.

Results

Both lncRNAs, NEAT1 and Lnc-DC were significantly upregulated in ITP patients in comparison to controls (p <0.0001 and P= 0.001 respectively). Furthermore, significant upregulation of the expression levels of NEAT1 and Lnc-DC were observed in the non-chronic compared with chronic ITP patients. Also, there was significant negative correlation between each of NEAT1 and Lnc-DC and platelet counts before treatment (r= -0.38; P= 0.003 and r= -0.461; P< 0.0001, respectively).

Conclusions

serum lncRNAs, NEAT1 and Lnc-DC could be used as potential biomarkers in differentiating childhood ITP patients and healthy controls in addition to differentiating non-chronic from chronic ITP which may provide a theoretical basis for the mechanism and treatment of immune thrombocytopenia.

Primary immune thrombocytopenia: a 'diagnosis of exclusion'?

Current diagnosis of primary immune thrombocytopenia (ITP) is presumptive, centered on excluding other causes of thrombocytopenia. The diagnosis of ITP is challenging because of the wide range of potential inherited and acquired causes of thrombocytopenia. The treatment of ITP is empiric with steroids, high-dose immunoglobulin, immunosuppressants and thrombopoietin agonists with potential side effects. We searched Medline and Cochrane databases, reviewed the study data and analyzed the individual diagnostic tests for their evidence-based role in the diagnosis of ITP. We then analyzed the strength of the scientific evidence for each diagnostic test in the diagnosis of ITP and identified gaps in the diagnostic accuracy. The diagnostic challenges in ITP include: insufficient evidence for the individual test for diagnosis of ITP, no standardized protocol/guideline for diagnosis, hurdles in accessing the available resources and failure to correlate the clinical data while reviewing the blood smear. We did not identify a diagnostic test that clinicians can use to confirm the diagnosis of ITP. In the absence of a diagnostic test of proven value in ITP, the clinician is best served by a comprehensive history and physical examination, complete blood count and review of the peripheral blood smear in evaluating thrombocytopenia.

Immature Platelet Dynamics in Immune-Mediated Thrombocytopenic States

A major challenge encountered by clinicians is differentiating presentations characterized by significant thrombocytopenia due to overlapping clinical symptoms and signs in the setting of ambiguous laboratory results. Immature platelets represent the youngest platelets that can be measured in peripheral blood by current hematology analyzers. These young platelets are larger, with higher RNA content recently released from the bone marrow. Thrombocytopenic presentations caused directly or indirectly by immune responses can lead to compensatory bone marrow responses seeking to normalize the platelet count; thus obtaining absolute immature platelet counts may be informative while triaging patients. Over the last decade, their use has expanded beyond being an early biomarker of bone marrow reconstitution post-hematopoietic stem cell transplantation to being used to establish bone marrow responses to infection and thrombocytopenias due to immune etiologies. Its accessibility as part of more detailed platelet indices obtained with routine laboratories makes it a promising option to understand the bone marrow's real-time response to disease states characterized by thrombocytopenia. This review will look at the immature platelet count as a biomarker, while presenting current attempts trying to understand how it could be used in thrombocytopenias occurring secondary to a given immune etiology.

Reticulated Platelets in Medicine: Current Evidence and Further Perspectives

Reticulated platelets (RPs) are young thrombocytes, newly released from the bone marrow. The identification and quantification of these cells remained difficult for decades due to a lack of standardized preanalytical and analytical methods. With the introduction of automated hematology analyzers in clinical routine, the determination of RPs, either as a total count or as a fraction, became more reliable, faster and more affordable. Currently, RPs are the focus of research in multiple clinical settings. In cardiovascular medicine, recent studies have focused on the relationship between RPs, coronary artery disease (CAD) and clinical outcomes, as well as the impact of RPs on the effects of antiplatelet therapy. Cohort studies showed increased levels of RPs in patients with acute coronary syndrome (ACS) or cardioembolic stroke. In patients with ACS, increased levels of RPs were also associated with an increased incidence of major ischemic cardiovascular events during follow-up. Further studies showed an association of levels of RPs with the antiplatelet response to less-potent P2Y12 inhibitors. In patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation, levels of RPs differed significantly depending on the achieved rhythm (sinus rhythm vs. recurrent atrial fibrillation). Levels of RPs appear to also be predictive for bleeding events in patients with various hematological diagnoses. Although no causal relationship has so far been proven, RP values have been associated with a large number of pathologies and clinical scenarios. This review summarizes the current evidence with regard to RPs and their potential diagnostic and prognostic value for noncardiovascular patients and for cardiovascular patients in particular. It describes further perspectives on how the testing of these cells might improve the treatment of cardiovascular patients.