Red blood cells modulate structure and dynamics of venous clot formation in sickle cell disease.

Sickle cell disease (SCD) is associated with chronic activation of coagulation and an increased risk of venous thromboembolism. Erythrocyte sickling, the primary pathologic event in SCD, results in dramatic morphological changes in red blood cells (RBCs) because of polymerization of the abnormal hemoglobin. We used a mouse model of SCD and blood samples from sickle patients to determine if these changes affect the structure, properties, and dynamics of sickle clot formation. Sickling of RBCs and a significant increase in fibrin deposition were observed in venous thrombi formed in sickle mice. During ex vivo clot contraction, the number of RBCs extruded from sickle whole blood clots was significantly reduced compared with the number released from sickle cell trait and nonsickle clots in both mice and humans. Entrapment of sickled RBCs was largely factor XIIIa-independent and entirely mediated by the platelet-free cellular fraction of sickle blood. Inhibition of phosphatidylserine, but not administration of antisickling compounds, increased the number of RBCs released from sickle clots. Interestingly, whole blood, but not plasma clots from SCD patients, was more resistant to fibrinolysis, indicating that the cellular fraction of blood mediates resistance to tissue plasminogen activator. Sickle trait whole blood clots demonstrated an intermediate phenotype in response to tissue plasminogen activator. RBC exchange in SCD patients had a long-lasting effect on normalizing whole blood clot contraction. Furthermore, RBC exchange transiently reversed resistance of whole blood sickle clots to fibrinolysis, in part by decreasing platelet-derived PAI-1. These properties of sickle clots may explain the increased risk of venous thromboembolism observed in SCD.

Clinical and immunological characteristics of antiphospholipid syndrome in an Asian population: a retrospective study.

OBJECTIVES: To describe the characteristics of patients with antiphospholipid syndrome (APS) in an Asian clinical practice setting. METHODS: We conducted a single-center, retrospective study of APS patients attending the rheumatology or hematology clinics, between January 2012 and December 2016. RESULTS: There were 450 patients suspected of having APS referred to our clinics. Seventy-four (16.4%) were diagnosed of APS, 51% of which were definite. Fifty-two (70%) patients were classified as primary APS, 50% of which were definite APS. The most common clinical manifestation was stroke (33%), followed by deep vein thrombosis of the lower extremities (30%) and pulmonary embolism (19%). Hypertension and the presence of at least one established cardiovascular risk factor were independently associated with stroke. Seven (9%) patients had multiorgan thrombosis as their first presentation of APS, 71% of which ultimately suffered from permanent organ damage or died of severe thrombosis, despite not fulfilling the criteria for 'definite' catastrophic APS (CAPS). Late fetal loss was the most prevalent obstetric complication. The majority of patients (79%) tested positive for lupus anticoagulant (LAC), while only 32% tested positive for anti-cardiolipin antibodies. Triple positive profile was documented in 14% of the cohort. Overall, recurrent thrombosis and bleeding complications were recorded in 9% and 28%, respectively. CONCLUSION: APS patients in central Thailand demonstrated high prevalence of stroke, late fetal loss, LAC positivity, and multiorgan thrombosis at first presentation, leading to poor outcomes.

Adding MYC/BCL2 double expression to NCCN-IPI may not improve prognostic value to an acceptable level.

BACKGROUND: MYC/BCL2 double expression (DE) is associated with poor prognosis in patients with diffuse large B-cell lymphoma (DLBCL) receiving rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). This study aimed to determine whether the addition of DE to the National Comprehensive Cancer Network Internal Prognostic Index (NCCN-IPI) could improve the prediction of disease progression in patients with DLBCL treated with R-CHOP. METHODS: This confirmatory prognostic factor study retrospectively recruited patients with newly diagnosed DLBCL between January 1, 2014, and January 31, 2018, at Ramathibodi Hospital (RA) and Thammasat University Hospital (TU). The follow-up period ended on July 1, 2022. Tumors expressing MYC ≥ 40% and BCL2 ≥ 50% were classified as DE. We calculated the hazard ratios (HR) for progression-free survival (PFS) from the date of diagnosis to refractory disease, relapse, or death. Discrimination of the 5-year prediction was based on Cox models using Harrell's concordance index (c-index). RESULTS: A total of 111 patients had DE (39%), NCCN-IPI (8%), and disease progression (46%). The NCCN-IPI adjusted HR of DE was 1.6 (95% confidence interval [CI]: 0.9-2.8; P = 0.117). The baseline NCCN-IPI c-index was 0.63. Adding DE to the NCCN-IPI slightly increased Harrell's concordance index (c-index) to 0.66 (P = 0.119). CONCLUSIONS: Adding DE to the NCCN-IPI may not improve the prognostic value to an acceptable level in resource-limited settings. Multiple independent confirmatory studies from a large cohort of lymphoma registries have provided additional evidence for the clinical utility of DE.

External validation and comparison of IPI, R-IPI, and NCCN-IPI in diffuse large B-cell lymphoma patients treated with R-CHOP to predict 2-year progression-free survival.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive lymphoma. The standard first-line therapy for DLBCL consists of rituximab cyclophosphamide doxorubicin vincristine and prednisone (R-CHOP). About 50-70% of patients may be cured by R-CHOP. There was no data on external validation and comparison of the international prognostic index, revised-IPI (R-IPI), and enhanced-IPI (NCCN-IPI) to predict treatment outcomes in the middle-income country with a resourced-limited setting. OBJECTIVES: We aimed to externally validate and compare IPI, R-IPI, and NCCN-IPI in predicting 2-year progression-free survival (2-y PFS) of newly diagnosed DLBCL patients treated with R-CHOP. METHODS: This ambispective observational study recruited consecutive patients diagnosed between 1 January 2014 and 30 June 2020, with the last follow-up on 1 July 2022 from Thammasat University Hospital and Ramathibodi Hospital. We assessed discrimination by Harrell's concordance index (c-index), calibration by calibration plot, and absolute difference in survival (ADS) between the lowest-and the highest-risk groups. RESULTS: The cohort of 292 patients (median age 63 years and median follow-up 3.6 years) had 131 progressions and 96 deaths. The 2-y PFS was 63%. The c-indices were NCCN-IPI 0.6216, R-IPI 0.6004 (P = 0.215), and IPI 0.6104 (P = 0.463). The calibration plots of NCCN-IPI and R-IPI showed nearly perfect agreement (moderate strength), while IPI had miscalibrations. The ADSs were NCCN-IPI 52%, R-IPI 42%, and IPI 25%. CONCLUSION: NCCN-IPI is the best prognostic index compared to IPI and R-IPI in prior studies. However, the prognostic model for DLBCL patients treated with R-CHOP requires updating or integrating biomarkers to improve discrimination to the acceptable level (c-index 0.7).

Low vegetable intake is strongly associated with venous thromboembolism in Thai population.

Recent studies have demonstrated a much higher incidence of venous thromboembolism (VTE) among Asian patients compared with previous studies. This study aims to determine dietary and behavioral factors that may have contributed to this increase. A case-control study was conducted. Cases were objectively confirmed VTE between 2006 and 2009 at King Chulalongkorn Memorial Hospital. Patients with underlying cancer, antiphospholipid syndrome and arterial thrombosis were excluded. Controls were age and sex-matched healthy volunteers. Food consumption was assessed using a food frequency questionnaire modified from the Thailand National Health Examination Survey III previously validated in the Thai population. There were 97 cases and 195 controls. The mean age was 54.6 years and 70% were women. VTE patients consumed significantly less vegetable, fish and spicy food compared with normal individuals with an odds ratio (OR) for venous thrombosis of 3.74 [95% confidence interval (CI) 2.24-6.26, P < 0.001], 2.05 (95% CI 1.24-3.41, P = 0.005) and 2.30 (95% CI 1.29-4.11, P = 0.01), respectively. Additionally, thrombosis was associated with overweight (OR 2.1, 95% CI 1.21-3.62, P = 0.002), obesity (OR 3.1, 95% CI 1.46-6.74, P = 0.001) and estrogen uses (OR 3.7, 95% CI 1.05-13.2, P = 0.02), but not with smoking or lack of exercise. A multivariate analysis showed that low vegetable consumption (OR 3.74, 95% CI 1.85-7.55, P < 0.001), female hormones (OR 5.80, 95% CI 1.51-22.22, P = 0.011) and body mass index (BMI, P = 0.048) were independently associated with VTE. Low vegetable intake, hormonal use and high BMI are the risk factors for noncancer-related VTE in Thai population.