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Background: Platelet activation is an integral part of pathogenesis of Kawasaki disease (KD). However, there is paucity of literature on flow-cytometry based assessment of platelet activation in KD. We aimed to analyse monocyte-platelet aggregates (MPAs), one of the sensitive markers for platelet activation, by flow cytometry in children with KD. Findings: In this single-centre prospective study, we have enrolled 14 children with KD and results were compared with age-matched febrile (n = 15) and healthy (n = 13) controls. After gating monocytes in side-scatter plot, MPAs were identified based on CD14 and CD41 expression. Two (2) ml of blood samples for children with KD were collected at 3 phases of illness- acute stage before start of intravenous immunoglobulin or aspirin, 24 h after completion of IVIg infusion, and 3 months after acute episode of KD. Children with KD had a significantly higher MPA% values [Median (IQR)- 41.3% (26.6, 52.7)] when compared with febrile [Median (IQR)- 5.98% (2.98-9.72)] and normal [Median (IQR)- 4.48% (2.57-5.59)] controls, p<0.01. On follow-up, the MPA% showed a gradual decline in children with KD, but even at 3 months, the value [Median (IQR)- 7.55% (4.15-14.6)] was higher compared to healthy controls [Median (IQR)- 4.48% (2.57-5.59)]. Conclusions: Our results suggest that MPA% was significantly elevated in acute stages in children with KD and activated platelets may continue to persist even after systemic inflammation has subsided. Future studies are warranted whether objective evidence of platelet activation may guide the use of immunomodulatory and anti-platelet therapy in KD. [ABSTRACT FROM AUTHOR]

Introduction: We previously showed that patients with chronic kidney disease (CKD) Stage G4-5 have normal bleeding times. This made us question whether hemodialysis (HD) initiation was really necessary solely to improve platelet function. Methods: In this prospective observational study, two 5 ml citrated blood samples and one 2 ml EDTA blood sample were collected from incident HD patients fulfilling inclusion criteria prior to HD initiation (baseline sample) and after three sessions of short duration, low flow, counter-current HD. In each instance, one sample was used to perform Collagen adenosine diphosphate closure time (CADPCT) using the Platelet function analyzer (PFA 200, normal range 68-142 seconds) and the second for light transmission aggregometry (LTA) with ADP as agonist (normal ≥50%). Results: This study included 20 patients between October 2017 and February 2019. Overall, and in the subgroup with normal baseline CADPCT or LTA, there was no statistically significant improvement after HD. However, of the 30% of patients who had an abnormal baseline CADPCT, 50% attained a normal value after three HD sessions, and the overall reduction in CADPCT in this group was statistically significant (P = 0.02). Of those with a baseline normal CADPCT, 21% developed abnormal prolongation post HD. Conclusion: HD for the sole purpose of improving platelet function is only of benefit in the subgroup of patients with an abnormal CADPCT at baseline, with close to 50% normalizing their platelet function after three sessions of low flow, short duration, counter-current HD. [ABSTRACT FROM AUTHOR]

Vascular complications of sickle cell anemia (SCA) are influenced by many factors. Elevated plasma homocysteine (Hcy) is supposed to be an independent risk factor and is either genetic or nutritional origin. The present study evaluated the plasma Hcy level, MTHFR C677T gene polymorphism, effect of folic acid (FA) supplementation' and hemato-biochemical parameters in SCA and their effect on the vaso-occlusive crisis (VOC) in SCA patients of an Asian-Indian haplotype population. One hundred twenty cases of SCA (HbSS) and 50 controls with normal hemoglobin(HbAA) were studied. It was found that the plasma Hcy level is significantly higher (p < 0.0001) in patients with SCA (22.41 ± 7.8 μmol/L) compared to controls (13.2 ± 4.4 μmol/L). Moreover, patients without FA supplementation had a significantly (p < 0.001) higher Hcy level (27 ± 7 μmol/L) compared to those with supplementation (17.75 ± 5.7 μmol/L). Turkey-Kramer multiple comparison tests show that there is a significant difference (p < 0.05) in HbF percent, hemoglobin (Hb), platelet count, serum bilirubin (direct:Bil-D and total:Bil-T), aspartate transaminase (AST), lactate dehydrogenase (LDH), and plasma Hcy levels between mild and severe VOC. Between moderate VOC and severe VOC, there was a significant difference (p < 0.05) in HbF%, Bil-D, AST, Hcy. Pearson correlation revealed that plasma Hcy had a significantly (p < 0.05) positive correlation with AST, serum bilirubin (indirect and total), LDH, jaundice, stroke, VOC per year, and hospitalization per year whereas it was inversely correlated with HbF percentage, Hb level, and FA treatment. In the study population, increased plasma Hcy level, hemolysis, and platelet activation were found to influence VOC in SCA. [ABSTRACT FROM AUTHOR]

Abnormal primary hemostasis is believed to be the most significant contributor to uremic bleeding. This study aimed to describe the prevalence and profile of primary and secondary hemostatic disorders in patients with chronic kidney disease (CKD) Stages 4 and 5 and to determine their association if any, with degree of uremia. Stages 4 and 5 predialysis CKD patients attending nephrology outpatient clinic were prospectively recruited and the following bleeding parameters were measured in all patients: platelet count, bleeding time (BT), Factor VIII assay, von Willebrand factor antigen (vWF:Ag), vWF:ristocetin cofactor activity (vWF:RCo), ratio of vWF:ristocetin cofactor activity to vWF antigen (vWF:RCo/vWF:Ag), prothrombin time (PT), and activated partial thromboplastin time (aPTT). Forty-five patients (80%, males) with a mean age of 39.4 years, 82% (n = 37) in Stage 5 CKD, were recruited for the study. The prevalence of thrombocytopenia was significantly higher among patients from West Bengal (15/26, 57.7%) compared to other study patients (2/19, 10.5%; P = 0.001); however, all had macrothrombocytes with normal BT, suggestive of the Harris syndrome. Factor VIII, vWF:Ag, vWF:RCo, vWF:RCo/vWF:Ag ratio, BT, PT, and aPTT were abnormal in 0 (0%), 0 (0%), 0 (0%), 4 (8.8%), 1 (2.2%), 7 (15.6%), and 5 (11.1%) patients, respectively. Except for thrombocytopenia, the prevalence of hemostatic abnormalities did not differ between CKD Stages 4 and 5. Hemostatic abnormalities are uncommon in Stages 4–5 CKD and except for thrombocytopenia, are not associated with degree of uremia. Constitutional macrothrombocytopenia is associated with normal BT even in CKD. [ABSTRACT FROM AUTHOR]

Random Donor Platelet (RDP) derived from whole blood is the major source of platelets in India. At our centre, we prepare RDPs by buffy coat method after a holding period of 2-hours (THRDP) as per current regulatory guidelines. Overnight hold of buffy coats before RDP preparation (OHRDP) would logistically optimise the manpower usage at our centre. The aim of this study was to compare both in-vitro as well as in-vivo parameters of OHRDPs with THRDPs. Hematological (Platelet, leucocyte counts), physical (pH and Swirling) and biochemical parameters (pO2, pCO2, lactate, bicarbonate and glucose) as well as platelet activation markers were tested in THRDPs and OHRDPs each at Day-1 and Day-5 as in-vitro studies. Separately, in-vivo study was done where Corrected count increment (CCI) and percentage platelet recovery (PPR) were considered. All parameters were expressed as Mean ± Standard deviation and were analysed using paired t -test with level of significance, p < 0.05. OHRDPs had higher platelet counts and lower leucocytes and CD62 P expression than THRDPs. All other markers were well within the quality control range in both groups. No significant differences were seen in the two groups when comparing CCI and PPR. OHRDPs were found to be as good or better as compared to the THRDPs in the in-vitro part of our study. Additionally, there were no significant differences between the two groups when they were compared in vivo. This makes us conclude that overnight hold of buffy coats may be implemented at our center. [ABSTRACT FROM AUTHOR]