Fall In Platelet Count Research Articles

Utility of Atypical Lymphocytes and Large Immature Cells in Prediction of Dengue Severity.

Background: There is a clinical imperative to devise metrics to prognosticate dengue severity. Our objective was to determine the association between longitudinal trends in atypical lymphocytes and large immature cell count with platelet count and dengue severity. Materials and methods: Retrospective analysis of longitudinally measured clinical and hematological data from (n = 79) hospitalized dengue patients was done. Results: The cohort consisted of patients with dengue fever without warning signs (DFWOWS) (n = 40, females = 14, and age = 19.9 ± 14.6 years), dengue fever with warning signs (DFWWS) (n = 36, females = 13, and age = 16.1 ± 14.1 years) and severe dengue (n = 3, females = 2, and age = 5.3 ± 4 years). Platelet count increased at a rate of 11,524 cells/mm3/day, with a slower rate of rise as the severity increased (p = 0.001***). Concurrently hematocrit and neutrophil percentage decreased, while the lymphocyte percentage and white blood cell (WBC) count increased during the hospital stay. Every 1% increase in atypical lymphocyte count (ATY) was associated with a fall in platelet count by 16,963 cells/mm3 (p = 0.001***). A similar but weaker trend was found for large immature cells (LICs). Conclusion: The data support the usefulness of longitudinal tracking of atypical lymphocyte and large immature cell count for dengue prognosis. The time trends of the hematological parameters indicate the progression of patients from the critical to the recovery phase. How to cite this article: Peraka R, Koppula A, Muppala BS, et al. Utility of Atypical Lymphocytes and Large Immature Cells in Prediction of Dengue Severity. J Assoc Physicians India 2023;71(11):19-24.

Outcomes for necrotising enterocolitis (NEC) in babies born at the threshold of viability: a case–control study

BackgroundThe threshold for active management of babies born prematurely in the UK is currently 22 weeks. The optimal management strategy for necrotising enterocolitis (NEC) in babies born at or near...

Early‐onset heparin‐induced thrombocytopenia after cardiac surgery: Should we lose sleep?

Unfractionated heparin remains the preferred anticoagulant, bar none, for cardiac surgery requiring cardiopulmonary bypass (CPB).1 With the ubiquitous use of unfractionated heparin and the universal fall in platelet count that accompanies CPB, concern for heparin‐induced thrombocytopenia (HIT) arises frequently following cardiac surgery, even though the incidence of HIT in this setting is only 0.5%–1%.2

Temporal presentations of heparin‐induced thrombocytopenia following cardiac surgery: A single‐center, retrospective cohort study

BackgroundHeparin‐induced thrombocytopenia (HIT) is an important adverse drug reaction that can occur postcardiac surgery. Preoperative exposure to unfractionated heparin (UFH) is common, raising the issue of how frequently cardiac surgery‐associated HIT occurs after immunizing preoperative exposure to heparin. ObjectiveTo determine the frequency and clinical picture of HIT occurring within 4 days of cardiac surgery (early presentation) versus later presentations (typical, delayed). MethodsWe identified patients with laboratory‐confirmed HIT following cardiac surgery over 30 years in a single cardiac surgery center. Three different clinical presentations of HIT were identified: typical (HIT‐related platelet count fall beginning between postoperative days [PODs] 5–10), delayed (patients with falls after POD10 or who presented following hospital discharge), and early (established before POD5, including during cardiac surgery [acute intraoperative HIT]). ResultsOf 129 patients identified with HIT complicating cardiac surgery, 100 had typical and 16 had delayed presentation of HIT; only 13 patients (10.1%) presented with early HIT, all of whom had received exposure to UFH during the 10 days before cardiac surgery. No patient was identified in whom remote preoperative UFH exposure was implicated in explaining early HIT. Notably, five patients appeared to have had acute intraoperative HIT, without immediate adverse consequences. ConclusionsApproximately 90% of patients with HIT after cardiac surgery appear to develop this complication due to immunization triggered by cardiac surgery; however, in approximately 10% of patients, early presentation during the first four PODs (or intraoperatively) can be explained by recent immunizing exposure to heparin.

Anti‐platelet factor 4/heparin antibodies in patients with Hantaan virus infection

BackgroundHemorrhagic fever with renal syndrome (HFRS) induced by Hantaan virus infection and heparin‐induced thrombocytopenia (HIT) are associated with symptoms such as thrombocytopenia and thrombosis. However, related molecules, such as anti–platelet factor 4 (PF4)/heparin antibodies, in patients with HFRS have not been evaluated. ObjectivesTo test plasma levels of anti‐PF4/heparin antibodies and study the possible role of these antibodies in HFRS pathogenesis. MethodsIndirect ELISA was used to determine plasma levels of anti‐PF4/heparin antibodies in 75 patients with HFRS and 20 normal controls. The 4Ts (thrombocytopenia, timing of platelet count fall, thrombosis or other sequelae, and other causes of thrombocytopenia) scoring system was used to determine the probability of HIT occurrence. A PF4‐enhanced platelet activation assay was used to detect the pathological effects of anti‐PF4/heparin antibodies. The laboratory/clinical features and viral load of all the patients were also assessed. ResultsOf the 75 patients with HFRS enrolled instudy, 69 had thrombocytopenia. Platelet count was negatively correlated with Hantaan viral load. Moreover, the optical density (OD) values of plasma antibodies against PF4/heparin in normal controls were less than 0.65, 4 patients tested strongly positive for anti‐PF4/heparin antibodies (OD values, 1.51–3.87), 21 patients were weakly positive (OD values, 0.66–0.74), and 50 patients were negative (OD values, 0.16–0.65). Moreover, all 4 patients who tested strongly positive for anti‐PF4/heparin antibodies showed a low probability of HIT (4Ts score of 3 or less) and had negative results in the PF4‐enhanced platelet activation assay. ConclusionsHantaan virus infection produces nonpathogenic antibodies against PF4/heparin; however, the generation mechanism of these antibodies requires further study.

PB2302: HEPARIN-INDUCED THROMBOCYTOPENIA ANTIBODIES CAN MAINTAIN PLATELET-ACTIVATING PROPERTIES AFTER TWO SESSIONS OF THERAPEUTIC PLASMA EXCHANGE

Background: Therapeutic plasma exchange (TPE) has been used as a salvage therapy in a small subset of heparin-induced thrombocytopenia (HIT) patients (severe or refractory HIT, before heparin re-exposure during cardiac surgery, in bleeding patients and in autoimmune HIT). Existing data show that HIT antibodies can lose platelet-activating properties after one or two TPE sessions, while more sessions may be needed to decrease the antibody titer. However, results may be assay dependent. The utility of Heparin-Induced Multiple aggregometry (HIMEA) in this setting has not been evaluated. Aims: To assess the effect of TPE on pathogenic HIT antibodies using HIMEA before an emergency surgery for gynecologic malignancy. Methods: TPE was performed in a 72-year-old patient necessitating emergency surgery for a voluminous uterine sarcoma in the acute phase of HIT (10 days after diagnosis). TPE aimed to reduce post-operative thrombotic risk by decreasing pathogenic HIT antibodies in a patient presenting a high risk of post-operative thrombotic complications. Two consecutive sessions of TPE using Spectra Optia ® Apheresis System were performed immediately before surgery. During each plasma exchange 2 L of plasma were removed and replaced by 5% human albumin. Acid-Citrate-Dextrose (ACD) was used as anticoagulant. Blood samples were taken before and after each TPE session (TPE1 pre, TPE1 after, TPE2 pre, TPE2 after). Removed patient’s plasma collected to the plasmapheresis bag was also tested. IgG anti-PF4/heparin antibodies tested with Enzyme Immunosorbent Assay (EIA) (Hyphen ZYMUTEST™ HIA IgG, Hyphen Biomed) and Heparin-Induced Multiple aggregometry (HIMEA) (Multiplate, Roche) in the absence of heparin (HIMEA saline), in the presence of 1UI/ml unfractionated heparin (UFH) (HIMEA low) and in the presence of 100IU/ml UFH (HIMEA high) were assessed. Results: Patient’s 4T’s score was 7 (2 for platelet count fall, 2 for timing, 2 for catheter associated venous thrombosis and 1 for other causes), strongly positive IgG anti-PF4 antibodies (OD: 2.43, cut-off<0.3 units) and a HIMEA profile favoring HIT (typical sigmoid curve at HIMEA low, >50% decrease of AUC at HIMEA high, absence of platelet aggregation at HIMEA saline). She was treated with fondaparinux at 1.5 mg/ day due to sepsis-associated acute kidney injury requiring hemodialysis. Platelet count (PLT) were 168 G/l before surgery. After two TPE sessions antibody titers remained unchanged (TPE1 pre: 2.63 units, TPE1 after:2.19 units, TPE2 pre:2.51 units, TPE2 after:5.52 units). Moreover, platelet reactivity remained also strong as demonstrated by high area under the curve (AUC) values in HIMEA low (figure 1). Plasma from the collection bag showed strong EIA and platelet activation test reactivity. No thrombosis nor thrombocytopenia were observed in one month follow-up. Image:Summary/Conclusion: Two TPE sessions failed to reduce platelet-activating properties of HIT antibodies as assessed by HIMEA in a cancer patient. TPE could be considered as a therapeutic intervention that can reduce thrombotic risk in patients necessitating an urgent non-cardiac surgery in the acute phase of HIT. However, more data is needed on the clinical benefit and the optimal number of TPE sessions in this clinical setting. Functional assays assessing Fcγ receptor mediated platelet activation may help guide the timing of the surgery.

Utility of Red Cell and Platelet Indices Evaluation of Severity of Dengue Infection

Context: Dengue is the most common mosquito-borne viral illness in humans and transmitted by aedes aegypti. Infection may be asymptomatic or present with a mild febrile illness to a life-threatening shock syndrome and diagnosed by virological tests, serological tests, and complete blood count.&#x0D; Aim: The present study was undertaken to evaluate the role of red cell and platelet indices to assess disease activity and severity of dengue infection.&#x0D; Material and Methods: The present study was conducted at a tertiary level teaching hospital in Central Gujarat, India from November 2019 to August 2021.100 dengue positive cases and 100 controls (dengue negative case) were consecutively sampled. Epidemiological, clinical data and complete blood count were collected from online and offline registers of the Central Diagnostic Laboratory. Chi square test, independent sample T – test and Karl pearson coefficient of correlation were used for statistical analysis.&#x0D; Results: Dengue cases have frequently presented with fever 32.65% or fever with chills / rigor 66.33%, headache 37.76%, body ache 44.90% and bleeding manifestations like petechiae 5.10% and bleeding from gum, nose and rectum 5.15%. while, 18% cases have ascites and 07% cases were found to have pleural effusion in dengue positive cases. Haemoconcentration, fall in total WBC count, platelet count and plateletcrit have significant statistical association with severity of dengue infection. Platelet count was directly proportional to plateletcrit in dengue positive cases.&#x0D; Conclusion: Significant statistical association was presented between degree of leukopenia, thrombocytopenia, haemoconcentration and fall in plateletcrit with severity of dengue infection whereas plateletcrit has positive correlation with platelet count in dengue infection.

POS-054 UTILITY OF PLASMA EXCHANGE AND RITUXIMAB IN PERIOPERATIVE PERIOD AMONG PATIENTS OF COMPLEMENT-ASSOCIATED RENAL DYSFUNCTION UNDERGOING TRANSPLANTATION: REPORT OF THREE RARE CASES

POS-054 UTILITY OF PLASMA EXCHANGE AND RITUXIMAB IN PERIOPERATIVE PERIOD AMONG PATIENTS OF COMPLEMENT-ASSOCIATED RENAL DYSFUNCTION UNDERGOING TRANSPLANTATION: REPORT OF THREE RARE CASES

Indeterminate serotonin release assays are associated with a high mortality rate

BackgroundThe serotonin release assay (SRA) is considered the gold standard for diagnosis of heparin‐induced thrombocytopenia (HIT). Although the SRA holds high sensitivity and specificity when results are definitive, up to 10% of samples from patients with suspected HIT yield “indeterminate” results. ObjectivesWe aimed to study the clinical course of patients with indeterminate results. MethodsWe conducted a cohort analysis of 2056 patients that underwent SRA testing. ResultsOf 2056 total patients, 152 (7.4%) had indeterminate assays. The prevalence of thrombocytopenia <50,000 × 106 was higher in patients with an indeterminate or positive SRA, compared with a negative SRA (39.5% and 40.0% vs. 27.5%, p < 4.0 × 10–4). Patients with an indeterminate SRA were more likely to have been treated in the intensive care unit than patients with a positive SRA (93.3% vs. 73.7%, p = 0.03). The mean thrombocytopenia, timing of platelet count fall, thrombosis or other sequelae, and other causes for thrombocytopenia score in patients with indeterminate SRA was 2.9, corresponding to a HIT probability of <5%. Of 152 patients, 128 (78.9%) had heparin‐PF4 optical densities (ODs) below 0.60 OD, whereas four patients (2.6%) had ODs above 2.00 OD. Inpatient mortality was significant in patients with indeterminate SRAs compared with positive or negative SRA (49.3% vs. 21.1% and 27.2%, p < 2.4 × 10–10). ConclusionsOur data suggest that an indeterminate SRA may signal an in vivo platelet activation process that is not related to heparin but is associated with increased mortality.

Carica papaya ameliorates thrombocytopenia through upregulation of Interleukin-11 and modulation of thrombopoietin in mouse model of carboplatin-induced myelosuppression.

Carica papaya L. (C. papaya) is used as a folk medicine for the treatment of various diseases throughout the world. Recently, papaya leaves decoction has been effectively used for the prevention and treatment of thrombocytopenia. The current study was undertaken to evaluate the thrombopoietic and immunomodulatory activities of C. papaya leaves in the mouse model of carboplatin induced myelosuppression. Myelosuppression was induced by a single intraperitoneal injection of carboplatin (125mg/kg b. w.). Aqueous extract of C. papaya leaves (15mg/kg b. w.) was given orally by feeding tube from day 0-18 to preventivegroup to see the preventive effect and from day 6-18 to treatmentgroup for treatment effect. The results showed that the C. papaya leaves extract significantly decreased the fall in platelet count in preventive and treatment groups. Extract significantly prevented the fall in total WBCs count on day 12 and 18 in the preventive group, whereas it significantly elevated the WBCs count in treatment group on day 18. Significantly increased RBCs count in both groups was observed on day 18 after treatment with C. papaya leaves extract. Treatment with C. papaya leaves extract significantly upregulated the mRNA expression levels of thrombopoietic cytokine IL-11 in both preventive and treatment groups. It is also observed that restoration of normal platelet count might have been resulted owing to the synergistic effect of upregulated IL-11 which ultimately led to a significantly diminished TPO expression. Our data suggest that aqueous extract of C. papaya leaves possesses significant preventive and curative properties against thrombocytopenia.

Natural history of PF4 antibodies in vaccine-induced immune thrombocytopenia and thrombosis

AbstractThe COVID-19 pandemic has resulted in the rapid development of a range of vaccines against SARS-CoV-2. Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a rare but life-threatening complication of primarily adenoviral-based vaccines associated with the presence of antibodies to a PF4/polyanion neoepitope and measured by using enzyme-linked immunosorbent assays. Presented are serial anti–PF4/polyanion antibody, platelet, and D-dimer measurements in a large cohort of patients and their relation to relapse. Overall, 51% of patients using the Stago assay had persistently positive anti–PF4/polyanion levels 100 days' postdiagnosis, whereas 94% of patients monitored by using the Immucor assay remain positive. The median duration of positivity of the PF4 assay is 87 days, with 72% of patients remaining positive after a median follow-up of 105 days. The use of plasma exchange seemed to reduce anti–PF4/polyanion levels and increase platelet counts in the acute setting more rapidly than other therapies. The rate of relapse in this study was 12.6%, with all relapsed cases exhibiting persistently positive PF4 antibodies and falling platelet counts. Only one patient had extension of their thrombosis. Overall, despite the persistence of PF4 antibodies in 72% of patients, the rate of relapse was low and did not seem to result in recrudescence of the aggressive clinical picture seen at index presentation. Monitoring of these patients in the UK cohort is ongoing and will aid in definition of the natural history of this novel condition.

Chronic Hepatitis B Infection in Children

Source: Ling SC, Lin HHS, Murray KF, et al. Chronic hepatitis is common and often untreated among children with hepatitis B infection in the United States and Canada. J Pediatr. 2021;237:24-33.e12; doi:10.1016/j.jpeds.2021.05.035Investigators from multiple institutions conducted a prospective cohort study of children in North America with chronic hepatitis B to assess outcomes over time. The study was conducted by the Hepatitis B Research Network at 6 clinical sites in the US and 1 in Canada. Study participants were children >6 months and <18 years old at baseline with hepatitis B surface antigen (HBsAg) positivity and were enrolled between 2010 and 2017. After a baseline visit, study participants had follow-up visits at 24 and 48 weeks, and annually thereafter. Data collected included demographics and clinical information, and blood specimens were obtained for measurement of alanine aminotransferase (ALT), platelet count, HBsAg, Hepatitis B e antigen (HBeAg), and hepatitis B virus (HBV) DNA on a regular basis. Treatment with anti-HBV therapy was documented, as was meeting criteria for this treatment based on guidelines from the American Association for the Study of Liver Diseases (AASLD). ALT was classified as normal or elevated when levels were greater than the upper limits of normal (ULN). Study outcomes included clinical events such as death, development of cirrhosis, liver transplantation, development of hepatocellular cancer, ALT flares (ALT levels ≥400 U/L in male patients and ≥350 U/L in female patients), hepatitis B serologic and virologic outcomes, anti-HBV treatment, and decreases in platelet counts (as an indicator of liver fibrosis progression).Data were analyzed on 362 children. Overall, 79% of study participants were Asian, 74% were born outside of the US or Canada, and 98% acquired HBV through vertical transmission. At baseline, 81% of study patients had elevated ALT values, with 66% having values >1–3 times >ULN; 75% were HBeAg positive. Median duration of follow-up in participants was 4.2 years (range 0.8–7.9 years). One study child died from a cause not related to liver disease, and 1 participant developed cirrhosis at age 14 years. Over the course of the study, 13 children had ALT flares, and there was an association between acute fall in platelet counts and occurrence of an ALT flare. At the last follow-up, ALT levels were elevated in 72% of patients. There were 40 patients treated with anti-HBV drugs. However, of 129 children who met AASLD criteria for anti-HBV treatment, only 25 (19%) received it. During the follow-up period, 2.4% of study patients became HBsAg negative, 15% of those who had detectable HBV DNA at baseline had unquantifiable levels measured at least once, and 20.8% of those who were HBeAg positive at baseline became HBeAg negative.The authors conclude that, among children in the US and Canada with chronic hepatitis B, many remained at risk for chronic liver disease.Dr Brady has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.HBV is efficiently transmitted from infected pregnant women to their newborn infants via blood exposures during labor and delivery.1 These infants are at increased risk of chronic HBV infection and its late complications of end-stage liver disease and liver cancer.2 The best strategies to prevent chronic HBV infection are to test pregnant women for HBsAg, refer women with positive HBsAg for potential treatment, immunize all infants with HBV vaccine at birth, and for those infants born to mothers with positive HBsAg, provide both HBV vaccine and hepatitis B immune globulin (HBIG), preferably within 12 hours of delivery.1 These strategies may not be available to infants born outside the US and Canada, and therefore screening for HBV infection should be included in the initial testing of immigrant and internationally adopted children, especially those from Asia.3Children who are positive for HBsAg need follow-up testing to see if the antigen clears. Those who have persistent positive HBsAg for at least 6 months are defined as chronically infected.1 Diet and exercise should be optimized to minimize their development of nonalcoholic fatty liver disease, which can contribute to additional liver injury.4 Referral to a hepatologist facilitates additional investigations and early appropriate initiation of anti-HBV therapies.5Another group of children and adolescents who need screening for chronic HBV infection is those with inflammatory bowel disease and rheumatologic conditions who are candidates for tumor necrosis factor alpha (TNF-α) inhibitor therapies.6 Because TNF-α is a mediator of the immune response against HBV infection, TNF-α inhibitors may promote viral reactivation and potentially fatal liver failure.Chronic HBV infection can lead to liver cancer and liver failure. The major prevention strategy is receipt of the birth dose of HBV vaccine.

Thrombocytopenia Induced by Iodinated Contrast Media: A Systematic Review

Iodinated contrast media are routinely used in clinical practice for diagnostic and therapeutic purposes. Adverse effects of their administration have an incidence of 3 %, and mostly consist of mild skin allergic reactions, with severe reponses such as anaphylaxis representing only 0.22 %. Contrast-induced thrombocytopenia is an extremely rare, underdiagnosed condition that most often occurs after infusion of hyperosmolar contrast agents, with low-osmolarity compounds being less likely the trigger. We report a systematic review of this condition based on the currently available series of case reports (18), as well as the clinical course of the presentation and platelet count during episodes. The physiopathogenic mechanism remains unknown, although the presence of some immune-mediated process involving changes in platelet aggregation and activation is currently accepted. Platelet response is immediate (within a few hours after exposure to the contrast agent) and consists of a fall in platelet count to &lt; 20 x 109/L, which returns to normal at day 3 or 4. Diagnostic criteria are based on those by George and Arnold, the latter more specific for drug-induced thrombocytopenia. No routine diagnostic laboratory tests are presently available to establish a definite diagnosis, and treatment usually consists of support measures to prevent complications from occurring, but steroids, immunoglobulins, plasma exchange and/or platelet transfusions may be used. Despite its low incidence, iodinated contrast-induced thrombocytopenia is a complication to consider that may cause severe thrombocytopenia after administration of iodinated contrast agent during some diagnostic test and/or angiography.

Effect of Carica papaya Leaf Juice on Blood Cell Count of Busulfan-Induced Chronic Bone Marrow Aplasia in Mice

Introduction: Aplastic anemia is a syndrome of bone marrow failure comprising of peripheral pancytopenia and marrow hypoplasia. Recently, research has shown papaya leaf juice to increase blood cells counts.&#x0D; Aims &amp; Objectives: This research was planned to investigate the effect of papaya leaf juice on blood cell counts in busulfan induced myelosuppressed mice.&#x0D; Place and duration of study: Post Graduate Medical Institute, Lahore from September 2015 to December 2015. Material &amp;Methods: This animal experimental study comprised of 36 adult healthy Swiss albino mice weighing 30-35 g, divided randomly into three equal groups. Busulfan was given orally (14mg/kg) to induce myelosuppression to busulfan group and Carica papaya+ busulfan group on 8 occasions over a period of 23 days. Carica papaya leaf juice (10ml/kg) was given to the Carica papaya+ busulfan group daily for 23 days to observe its role in preventing myelosuppression. Normal group was given distilled water in an equivalent amount. One day after the final dose of busulfan and Carica papaya, the animals were sampled for blood cell counts. Data was analyzed using SPSS version 20. A p-value &lt; 0.05 and below was considered as significant.&#x0D; Results: The Carica papaya leaf juice not only prevented significant fall in hemoglobin (10.86 ± 1.455 g/dl), RBC (9.54 ± 0.954× 106/mm3) and platelet count (958.92 ± 176.22 x103/mm3) vs (9.70 ± 0.904,11.24 ± 0.952 g/dl), RBC count (6.5025 ± 1.43,10.43 ± 0.234× 106/mm3) and platelet count (627.83 ± 151.63, 3881.08 ± 83.13 x103/mm3) in busulfan group but also kept them close to normal range. Total leukocyte count in C.papaya treated group improved significantly to 8116.67± 1540.85/mm3 vs (4516.67±789.51, 6666.67±798.10/mm3) busulfan treated and normal groups respectively.&#x0D; Conclusion: The Carica papaya leaf juice possesses significant myeloprotective activity. It may be a good candidate for prevention of chemotherapy induced pancytopenia

Flow Cytometric Detection of Procoagulant Properties of Plasma from Patients with Clinically Confirmed Vaccine-Induced Immune Thrombotic Thrombocytopenia

Background: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe prothrombotic complication of adenoviral vaccines including ChAdOx1 nCoV-19 (AstraZeneca) vaccine. The putative mechanism involves formation of pathological anti-PF4 antibodies that activate platelets via the FcγRIIa receptor to drive thrombosis and the associated thrombocytopenia. Functional assays are important in the VITT diagnostic pathway as not all detectable PF4 antibodies are pathogenic. Detection of procoagulant platelets (platelets supporting thrombin generation) in presence of PF4 has been proposed as a diagnostic assay for VITT (Althaus et al). Procoagulant platelets are not typically generated in response to low level agonist stimulation; however, combination of ligand binding of G-protein coupled receptors (GPCR) (eg. PAR1) and ITAM linked receptors (eg. GPVI, CLEC2 and FcγRIIa) synergistically induce procoagulant platelet formation. Here, we describe an alternative flow cytometric assay to diagnose VITT. We hypothesized that priming of platelets with a PAR1 agonist at a level sufficient to release PF4, but insufficient to generate a significant procoagulant response in donor platelets, would provide a platform in which procoagulant response would be dependent on presence of FcγRIIa dependent procoagulant antibodies in patient plasma, without requirement for additional PF4.Methods: Our previously established flow cytometry-based procoagulant platelet assay (using cell death marker GSAO and P-selectin) was modified to incorporate exogenous patient plasma and performed on whole blood from healthy donors screened for FcγRIIa responsiveness (aggregation response to anti-CD9 antibody, ALB6), primed with 5 μM SFLLRN. The assay was performed on Australian patients referred for confirmatory VITT testing with probable VITT (confirmed thrombosis within 4-42 days of ChAdOx1 nCov-19 vaccination, D-Dimer > 5x ULN, platelets < 150 x 10 9/L or falling platelet count) after screening on PF4/heparin ELISA (Asserachrom HPIA IgG Assay, Stago Diagnostics). Procoagulant response was also measured in presence of 0.5 U/mL and 100 U/mL heparin, monoclonal FcγRIIa blocking antibody, IV.3, and intravenous immunoglobulin, IVIg. Some plasmas were incubated with ChAdOx1 nCoV-19 or SARS-CoV-2 spike protein. Flow cytometry positive patients were also tested by serotonin release assay (SRA) and multiplate aggregometry. Clinical correlation was obtained.Results: Citrated plasma from 49 unique patients with suspected VITT are reported. Plasma from ELISA+ve patients with clinical picture consistent with VITT (n=31), significantly increased the procoagulant platelet proportions in healthy donors in presence of 5 μM SFLLRN (p<0.0001, Figure 1A). This increase was not seen with plasma from healthy donors (n=14); or individuals exposed to ChAdOx1 nCov-19 vaccine without VITT: thrombocytopenic thrombosis patients who were ELISA-ve and SRA-ve (n=14); or low-level ELISA+ve patients without thrombocytopenia who were negative by either multiplate or SRA (n=4). The procoagulant platelet response induced by VITT positive plasma was reduced with low dose heparin (0.5 U/mL, p<0.01) except for 3 patients who showed a heparin-enhancing effect (Figure 1B). High dose heparin (100 U/mL, p<0.0001), IV.3 (10 µg/mL, p<0.0001) or IVIg (10 mg/mL, p<0.0001) abolished the procoagulant response (Figures 1C-D). The in vitro effect of IVIg was predictive of the in vivo response to IVIg therapy (Figure 1E). Addition of SARS-CoV-2 spike protein had no effect on the procoagulant platelet response. ChAdOx1 nCov-19 had an inconsistent effect on procoagulant platelet formation in presence of VITT plasma. Use of donors without a robust aggregation response to ALB6 resulted in false negative results.Conclusion: Induction of FcγRIIa dependent procoagulant response by patient plasma, suppressible by high dose heparin and IVIg, is highly indicative of VITT in the correct clinical circumstance. This assay modification of priming donor platelets from known FcγRIIa responsive donors with a GPCR agonist to potentiate the ITAM signaling from platelet activating immune complexes, results in a sensitive and specific assay. This may represent a functional platform that can be adopted into diagnostic laboratories to identify patients with platelet-activating antibodies and potentially predict treatment responses. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Asymptomatic immune thrombocytopenia in immediate post surgery following fresh frozen plasma transfusion

Occurrence of thrombocytopenia in immediate post operative period is less frequently encountered, and identifying the cause(s) is also challenging. Because multiple interventions in the form of fluid administrations, blood products transfusion, use of drugs (heparin) and increased risk of infection and organ dysfunction in post operative period can all cause thrombocytopenia. Fresh frozen plasma transfusion (FFP) transfusion is an uncommon cause of drastic thrombocytopenia, with only 14 such reported cases in the literature. And this complication is most frequently witnessed in perioperative period, 11 out of 14 of all reported cases. It is explained by transfusion of plasma containing antibodies against platelets, which develop as a consequence of plasma donors being exposed to varied platelet antigen via previous blood transfusion or during pregnancy. Here we are presenting a case of a young male who was transfused with FFP in post-operative period which led to a drastic fall in platelet count without any bleeding manifestations, which was a diagnosis of exclusion and managed with suspension of FFP transfusion.

Clinical Decision Support System for Detection of Dengue

Dengue fever is caused due to the mosquito (Aedel aegypti) bite. The symptoms of this fever are similar to other fevers such as Malaria, Chikungunya and Zika. A common sign of Dengue fever is the sharp fall of blood platelet count, amongst other a host of other confusing symptoms, which makes Dengue difficult to diagnose, especially by an inexperienced physician. The purpose of this study is to outline a decision support system (DSS) which would come to the aid of detection of Dengue fever by carrying out an analysis of AHP and fuzzy AHP (FAHP) methodology. The data of confirmed Dengue as diagnosed by a physician is picked up, examined independently using AHP and FAHP approach, the results obtained are then compared with the diagnosis report of an expert doctor. The outcome is encouraging and indicates that expert systems can be leveraged for the diagnosis of Dengue and can be a useful tool for non-expert physicians

Tocilizumab mitigates hypercoagulability after out-of-hospital cardiac arrest – results from a randomized controlled trial (IMICA)

Abstract Background Systemic inflammation constitutes a key element of the post cardiac arrest syndrome (PCAS) which affects initially comatose resuscitated cardiac arrest patients. We have recently shown that treatment with tocilizumab, an IL-6 receptor antagonist, reduces systemic inflammation and myocardial injury after out-of-hospital cardiac arrest (OHCA). Inflammation and coagulation are interconnected, and changes in coagulation often accompany inflammatory states. Purpose To investigate if conventional coagulation parameters or a viscoelastic hemostatic assay differ in patients treated with tocilizumab compared to placebo. Methods Eighty comatose OHCA patients were randomized 1:1 in a double-blinded placebo-controlled trial to a single infusion of tocilizumab or placebo in addition to standard of care including targeted temperature management. Trial registration: Clinicaltrials.gov NCT03863015. Endpoints were plasma fibrinogen, platelet count, and Thrombelastography (TEG) variables. TEG analysis was performed utilizing whole blood in a citrated kaolin assay with heparinase (to neutralize any unfractionated or low molecular weight heparin that had been administered), and the following variables were analyzed: reaction time (R), angle, maximum amplitude (MA), and lysis at 30 minutes (Ly30) which represents clot initiation, propagation, strength and dissolution respectively. Data reported as median (Q1; Q3), statistical analysis performed by constrained linear mixed models, and a p&amp;lt;0.05 was considered statistically significant. Results Admission median levels of the investigated coagulation parameters were within normal levels for both the tocilizumab and placebo group. At 48 hours, for the placebo group, fibrinogen levels (figure 1) had risen to supra-normal levels, TEG angle had increased from 64 (10; 67) till 72 (69; 74), and TEG MA (figure 2) had increased to the hypercoagulable range (all p&amp;lt;0.05), while for the tocilizumab group fibrinogen levels and TEG MA remained within normal values. Both groups had a significant fall in platelet count from admission till 48h [placebo: from 252 109/L (208; 282) till 151 (126; 189); tocilizumab from 217 (183; 260) till 152 (127; 183)], with no group differences. Also for both groups there was significant shortening of the TEG R time [placebo: from 8 min (6; 10) till 6 (6; 8); tocilizumab from 8 (6; 9) till 7 (6; 8)], again with no difference between groups. Ly30 did not change over time or differ between groups. Conclusion Treatment with tocilizumab following resuscitated OHCA aids in maintaining a normo-coagulable state, whereas placebo patients developed supra-normal fibrinogen levels and a hypercoagulable TEG clot strength. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Danish Heart Foundation (Reference no. 19-R135-A9302-22125); Region Hovedstadens Forskningsfond til sundhedsforskning (CapitalRegion Research Foundation, Denmark; reference no. A6030) Figure 1. FibrinogenFigure 2. Thrombelastography MA

Dabigatran as first-line treatment for heparin-induced thrombocytopenia in the intensive cardiac care setting

Abstract Introduction Heparin-induced thrombocytopenia (HIT) is a rare immune-mediated disorder related to the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) which is associated with increased risk of vascular thrombosis. HIT constitute a relevant and not so uncommon clinical issue in the intensive cardiac care unit setting. Parenteral non-heparin anticoagulants are recommended for the treatment of HIT. The efficacy of dabigatran, direct oral anticoagulant, is poorly documented in this indication. In laboratory-confirmed HIT only few cases with short-term use and early conversion to and from another anticoagulant were reported. Purpose The purpose of our study was to evaluate the efficacy and safety of dabigatran as a first-line and the only one anticoagulant used in the treatment of HIT. Methods We prospectively enrolled 5 patients with the diagnosis of HIT who were hospitalized in our intensive cardiac care unit in 2017–2021. Heparin was stopped immediately on the suspicion of HIT and off-label dabigatran therapy was initiated the same day. There were no conversion to another non-heparin anticoagulant – dabigatran was used continuously from suspicion of HIT for at least 3 months. In all patients we used latex immunoassay to confirm the diagnosis of HIT. Lower-extremity compression ultrasonography was performed to exclude thrombosis. We distinguished HIT with thrombosis (HITT) and isolated HIT (HIT without thrombosis). The minimal follow-up period on dabigatran treatment was 3 months and the maximal 4 years. Results All the patients were male with the median age of 73 years (interquartile range, 52–78 years) and all were exposed to both, UFH and LMWH. The median platelet (PLT) count before exposition to heparin was 182000/μl (interquartile range, 171000/μl–321000/μl). Platelet count fall &amp;gt;50% was observed after a median time of 9 days (interquartile range, 7–11 days) after exposition to heparin and a median PLT count nadir was 87000 μl/l (interquartile range, 25000/μl–103000/μl). Two patients had intermediate and three high probability of HIT. HITT was diagnosed in one patient. The manifestation of HITT was upper-extremity arterial thrombosis and pulmonary embolism. Four patients were diagnosed with isolated HIT. PLT count recovery &amp;gt;15ehab724.2982/μl was observed after a median time of 3 days on dabigatran treatment (interquartile range, 2–7 days). In the patient with HITT, a complete resolution of upper-limb arterial thrombosis was observed. At the minimal observation period end point (3 months) all the patients survived without bleeding or new thrombotic event. Moreover, neither bleeding nor recurrence of HIT occurred during the total follow-up period. Conclusion Dabigatran is safe and efficient as first-line treatment for HIT and can be used as the only one anticoagulant in this challenging, clinical scenario. Funding Acknowledgement Type of funding sources: None.

The path of uncovering a prothrombotic thrombocytopenic syndrome after viral vector‐based COVID‐19 vaccination: Where there is much light, the shadow is deep

The path of uncovering a prothrombotic thrombocytopenic syndrome after viral vector‐based COVID‐19 vaccination: Where there is much light, the shadow is deep