Abnormal frequency of the memory B cell subsets and plasmablasts in patients with congenital severe hemophilia A: correlation with "Inhibitor" formation.

BACKGROUND: Development of antibodies against infused Factor VIII (FVIII) or "inhibitors" represents a major challenge following FVIII replacement therapy in patients with hemophilia A (HA). Recent studies have shown that certain cellular compartments of the immune system contribute to the production of such antibodies. Herein, we determined the frequency of class-switched CD19+IgD-CD27+/non-class-switched CD19+IgD+CD27+ memory B cell subsets and CD19+CD27hiCD38hi plasmablasts in patients with severe HA and their association with the development of inhibitors in these patients. METHODS: This cross-sectional case-control study enrolled 32 patients with severe HA, including 8 with and 24 without inhibitors, and 24 healthy individuals. The frequencies of the memory B cell subsets and plasmablasts were determined using flow cytometry. RESULTS: The frequency of CD19+IgD+CD27+ non-class-switched memory B cells was significantly lower in patients with HA (including both patients with and without inhibitors) than in healthy controls. The percentages of both CD19+IgD-CD27+ class-switched and CD19+IgD+CD27+ non-class-switched memory B cells did not differ significantly between patients with and without inhibitors. HA patients with inhibitors had significantly higher proportions of CD19+CD27hiCD38hi plasmablasts than the control group as well as the inhibitor (-) ones. No significant correlation was observed between the inhibitor levels with the percentages of memory B cell subsets and plasmablasts. CONCLUSION: This study is the first to demonstrate a dysregulated proportion of CD19+IgD+CD27+ non-class-switched memory B cells and CD19+CD27hiCD38hi plasmablasts in patients with severe HA. Therefore, strategies targeting memory B-cell/plasmablast differentiation may have promising outcomes in the management of inhibitor formation in patients with severe HA.

Altered frequency of FOXP3+ regulatory T cells is associated with development of inhibitors in patients with severe hemophilia A.

INTRODUCTION: The development of anti-factor VIII (FVIII) antibodies or "inhibitors" is a major complication following FVIII replacement therapy in patients with severe hemophilia A (HA), rendering the treatment inefficient. Data on the role of regulatory T cells (Tregs) in inhibitor formation in these patients are rare. Herein, we aimed to investigate whether a difference in the FOXP3+ Tregs is linked to the formation of the inhibitors in severe HA patients. METHODS: In this cross-sectional study, 32 patients with severe HA (8 patients with inhibitors and 24 without inhibitors) and 24 healthy controls were enrolled. The frequency of FOXP3+ Tregs was determined using multicolor flow cytometry method. RESULTS: Our results showed that the median level of CD4+ CD25+ FOXP3+ Tregs did not significantly differ between HA patients and healthy controls and between HA patients with and without inhibitors (P > 0.05). However, patients with inhibitors had significantly lower amounts of CD4+ CD25- FOXP3+ Tregs compared to those without inhibitors as well as healthy controls (*P = 0.012 and *P = 0.004, respectively). The frequency of CD4+ CD25+ T cells was significantly higher in HA patients who developed inhibitors compared to the inhibitor-negative ones whereas they were lower in inhibitor-negative patients compared to the healthy controls (*P = 0.013 and *P = *0.029, respectively). The percentages of CD4+ CD25+ T cells were positively correlated with the levels of inhibitors in HA patients (r = 0.45, *P = 0.021). CONCLUSION: Our data demonstrated for the first time that the CD4+ CD25- FOXP3+ Tregs might be implicated in the prevention of inhibitor formation in severe HA patients.

Comparison of Commercial Low Molecular Weight Heparin and Homemade Anti-Xa Calibrators to a Commercial Specific Anti-Xa Calibrator for Plasma Rivaroxaban Quantification by Anti-Xa Oral Anticoagulant Plasma Concentration Chromogenic Assay.

OBJECTIVE: The main concern about measuring the concentration of rivaroxaban by anti-Xa assay in some laboratories is the lack of a commercial specific calibrator in emergencies. Therefore, this study aimed at providing a homemade anti-Xa calibrator and commercial low molecular weight heparin (LMWH) anti-Xa calibrator. METHODS: The anti-Xa plasma concentration of rivaroxaban was measured in 70 patients using a commercial specific anti-Xa calibrator, a commercial LMWH anti-Xa calibrator, and a homemade anti-Xa calibrator. RESULTS: We demonstrated a significant correlation and agreement (P < .001) between LMWH-calibrated anti-Xa and the commercial specific calibrator. A significant correlation (P < .001) was found between homemade calibrated anti-Xa made by normal pooled plasma and that calibrated with a commercial specific drug. The nonspecific homemade and LMWH calibrators had excellent agreement (P < .001) and can be used interchangeably. CONCLUSION: Our data showed that for estimating rivaroxaban concentrations, the LMWH calibrator could be used as an alternative calibrator in the anti-Xa assay.

Epidemiologic study of patients with thrombotic events referred to a tertiary hospital in Southern Iran.

BACKGROUND AND AIM: Thromboembolic events mainly occur in older age is related with high morbidity and mortality, and considerable health-care costs particularly in developing countries. Both arterial and venous thromboembolism has known risk factors such as hyperlipidemia, obesity, diabetes, cancer, major surgery, central catheter. We aimed to evaluate the occurrence of thrombotic events and related risk factors in a group of Iranian patients. METHODS: In this cross-sectional study, all patients (n = 99) who were complicated by thrombotic events referred to the Hematology Research Center of Shiraz University of Medical Sciences were investigated from 2015 to 2017, in Shiraz, Southern Iran. Data were collected from their medical records by a designed data gathering form. RESULTS: The median age of the occurrence of thrombosis was 51 (IQR: 31) years. From all thrombotic events 52.5% occurred in females. Venous thrombosis was more prevalent than arterial (61.6% vs. 38.4%). Hypertension, diabetes mellitus and ischemic heart disease were the most associated disease with thrombosis. Most of the patients (79.8%) had no episodes of relapse and the occurrence of relapse had no significant relationship with thrombophilia and underlying disease. Acceptable response rate for warfarin therapy was achieved in 46.5% with 5 mg and 43.4% with 5-7.5 mg. CONCLUSION: Knowing the frequency and risk factors for thrombotic events lead to timely diagnosis and management of thrombosis. Atrial fibrillation and valvular rheumatic heart disease are the most common risk factors of thrombosis in our study showing prophylaxis is necessary in high-risk patients.

Evaluation of Efficacy, Safety, and Satisfaction Taking Deferasirox Twice Daily Versus Once Daily in Patients With Transfusion-Dependent Thalassemia.

OBJECTIVE: Deferasirox is a once-daily oral iron-chelation agent approved by the US Food and Drug Administration in November 2005. The authors aimed to evaluate efficacy, safety, and satisfaction of patients regarding twice-daily dose of deferasirox in patients with thalassemia who are resistant to once-daily regimen. METHODS: In this historical cohort multicenter study, 34 patients with beta-thalassemia major resistant or intolerant to once-daily dose of deferasirox (35 mg/kg/d) were investigated in 2016. Patients were registered at 3 thalassemia referral centers in Shiraz, southern Iran and Tehran, the capital of Iran. All patients were followed for 1 year and monitored by regular physical examination, laboratory data, serum ferritin levels, and heart and liver T2 magnetic resonance imaging. RESULTS: Mean age of thalassemia patients was 25.6±8.1 (8 to 40) years, including 22 female individuals and 12 male individuals. Serum ferritin levels significantly decreased during the study period (2021±955 at baseline vs. 1228±894 at the end of the study, P<0.001). Liver T2 magnetic resonance imaging of the patients demonstrated a significant improvement during the study. 73.3% of patients showed normal values at the end of study compared with 28.1% at the baseline (P<0.001). Drug side effects were reported only in 2 patients (5.8%) including 1 patient with abdominal pain and 1 with leukopenia and thrombocytopenia. CONCLUSIONS: It seems that deferasirox can be used with increased dose and twice daily with acceptable efficacy in unresponsive or intolerant thalassemia patients to once-daily dose. Close monitoring of the patients is necessary to detect and manage any possible adverse events.

Distribution of alpha-thalassemia mutations in Iranian population.

BACKGROUND: Alpha-thalassemia as one of the most common monogenetic disorders is widely spread over the Mediterranean, Southeast Asian, and Middle Eastern populations, including Iran. Although beta-thalassemia is much more common than alpha-thalassemia, alpha-thalassemia is still one of the main health problems in Iran with different mutation frequencies in various ethnic groups. So the evaluation of alpha-thalassemia mutations could be helpful to detect carriers as well as prevention strategy in Iranian population. OBJECTIVES: The aim of this study was to investigate the spectrum and frequencies of alpha-globin mutations in different ethnic groups of southern Iran. MATERIALS AND METHODS: Common alpha-globin mutations were evaluated in 4010 Iranian population using a reverse dot blot for all point mutations and gap-polymerase chain reaction. RESULTS: Out of all individuals, 3993 were distinguished as carriers of alpha-thalassemia mutations. Thirteen types of alpha-thalassemia mutations were discovered. Allele of α(3.7) mutation was the most prevalent (43.84%) followed by the α(IVS1/-5NT) allele with the prevalence of 4.91%. The less frequent alleles were Hb ICARIA and α(codon16) with the prevalence of 0.04 and 0.01%, respectively. CONCLUSION: Our findings are essential for carrier screening, genetic counseling, and prenatal diagnosis in order to decrease the prevalence of α-thalassemia in Iran which is one of the goals of the national screening program.