Molecular characteristics of hereditary red blood cell membrane disorders in Thailand: a multi-center registry

Red blood cell (RBC) membrane disorders represent a significant category of hereditary hemolytic anemia; however, information from Southeast Asia is limited. We established a national registry aiming to characterize RBC membrane disorders and their molecular features in Thailand. A total of 100 patients (99 kindreds) diagnosed with RBC membrane disorders between 2011 and 2020 from seven university hospitals were enrolled. The most prevalent disorders observed were hereditary elliptocytosis (HE; n=33), hereditary pyropoikilocytosis (HPP; n=28), hereditary spherocytosis (HS; n=19), Southeast Asian ovalocytosis (SAO; n=10 of 9 kindreds), and two cases of homozygous SAO. The remaining cases were grouped as unclassified membrane disorder. Seventy-six patients (76%) were molecularly confirmed by PCR, direct DNA sequencing, or hi-throughput sequencing. The primary causative gene for HE and HPP was SPTB, accounting for 28 out of 29 studied alleles for HE and 56 of 56 studied alleles for HPP. In the case of HS, dominant sporadic mutations in the ANK1 gene (n=4) and SPTB gene (n=3) were identified as the underlying cause. Notably, the four most common variants causing HE and HPP were SPTB Providence (c.6055 T>C), SPTB Buffalo (c.6074 T>G), SPTB Chiang Mai (c.6224 A>G), and SPTB c.6171__82delins TGCCCAGCT. These recurrent SPTB mutations accounted for 79 out of 84 mutated SPTB alleles (94%). In summary, HE and hereditary HPP associated with recurrent SPTB mutations are the predominant types of RBC membrane disorders observed in Thailand. These findings have significant implications for the clinical management and future research of RBC membrane disorders in the region.

Thalassemia-related complications in pediatric, adolescent, and young adult patients with transfusion-dependent thalassemia: A multicenter study in Thailand

INTRODUCTION

Management of transfusion-dependent thalassemia (TDT) can be challenging due to numerous potential disease-related complications and comorbidities in particular age groups. The objective of this study was to report thalassemia-related complications and risk factors in pediatric, adolescent, and young adult patients with TDT.

METHODS

A multicenter web-based registry was conducted in patients with TDT aged 25 years and younger from eight university hospitals covering all parts of Thailand. Factors significantly associated with each complication were analyzed by logistic regression methods.

RESULTS

Of 605 patients, 267 thalassemia-related complications were reported from 231 pediatric, adolescent, and young adult patients with TDT patients (38.2%). The most common complications were infections, followed by cholelithiasis and growth failure. Splenectomy and elevated pre-transfusion hemoglobin were statistically significant risk factors for infections (adjusted odds ratio [AOR] = 2.3, 95% confidence interval [CI]: 1.2-4.5, p-value = .01 and AOR = 1.5, 95% CI: 1.2-1.7, p-value < .005, respectively). There were two statistically significant risk factors conferred endocrinopathies, including older age (AOR = 1.06, 95% CI: 1.01-1.1, p-value = .01) and being male (AOR = 2.4, 95% CI: 1.4-4.0, p-value = .002).

CONCLUSION

Nearly 40% of the patients in this cohort had thalassemia-related complications. Periodic surveillance and optimal care for respective complications may minimize comorbidities in pediatric, adolescent, and young adult patients with TDT.

Association of osteoporosis and sarcopenia with fracture risk in transfusion-dependent thalassemia

Patients with transfusion-dependent thalassemia (TDT) have an increased risk of osteoporosis and fractures. They also have several potential factors associated with sarcopenia. There has been currently no study on sarcopenia and its association with falls and fractures in TDT. This study aims to determine the prevalence of and factors associated with osteoporosis, fragility fractures, and sarcopenia in adults with TDT. A cross-sectional study was conducted at the hematologic clinic at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Clinical data and laboratory testing were collected. Bone mineral density and morphometric vertebral fracture were assessed. Sarcopenia was defined using the 2014 and 2019 Asian Working Group for Sarcopenia (AWGS) criteria. We included 112 TDT patients aged 35.1 ± 12.5 years. The prevalence of osteoporosis was 38.4%. Fragility fractures were found in 20.5% of patients. Lower BMI (OR 0.29; 95% CI 0.12-0.72, P = 0.007) and hypogonadal state (OR 3.72; 95% CI 1.09-12.74, P = 0.036) were independently associated with osteoporosis. According to the 2014 AWGS criteria, the prevalence of overall sarcopenia and severe sarcopenia was 44.6% and 13.4%, respectively. Severe sarcopenia was strongly associated with fragility fractures (OR 4.59, 95% CI 1.21-17.46, P = 0.025). In conclusion, osteoporosis, fragility fractures, and sarcopenia were prevalent in adults with TDT. Severe sarcopenia was associated with fragility fractures. Early osteoporosis and sarcopenia screening and prevention may reduce fracture risk and its complications in these patients.

Deferiprone, an iron chelator, alleviates platelet hyperactivity in patients with β-thalassaemia/HbE

Background

Hyperfunctional platelets play important roles in thromboembolism in patients with β-thalassaemia/ haemoglobin E (β-thal/HbE). Our previous study revealed ex vivo inhibitory effects of deferiprone on normal platelets. Herein, we aimed to investigate the in vivo effects on platelets in patients with β-thal/HbE.

Methods

A prospective, self-controlled clinical study on 30 patients with β-thal/HbE who had received therapeutic deferiprone (20.8-94.5 mg/kg/day) was conducted. The study included a 4-week washout period followed by 4 and 12 weeks of deferiprone treatment. Platelet aggregation was performed by a turbidimetric method. Levels of deferiprone and soluble platelet (sP)-selectin in serum were measured by high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) kit, respectively.

Results

The washout period significantly enhanced platelet hyperactivity both in patients who had undergone splenectomy and in those who had not. At 2 hours following the administration of a single dose of deferiprone, platelet sensitivity to ADP and arachidonic acid was significantly reduced. The inhibitory effects of deferiprone were gradually increased over the period of 4 and 12 weeks. Deferiprone also depressed sP-selectin levels, but the effect was stable over longer follow-up periods. Correlation analysis demonstrated the relationship between serum levels of deferiprone, sP-selectin, and platelet activities induced by ADP and arachidonic acid.

Conclusion

We first demonstrated the in vivo antiplatelet effect and benefit of short-term treatment of deferiprone in patients with β-thal/HbE. The impact on thrombotic outcomes deserves further study.

Stability of Hemoglobin Constant Spring Identified by Capillary Electrophoresis

Objective

Hemoglobin Constant Spring (HbCS) is often missed by routine hemoglobin analysis. The aim of this research was to study HbCS stability as identified by capillary electrophoresis (CE) to determine the specimen storage time limit.

Methods

The EDTA blood of 29 HbCS samples were kept at 4°C and analyzed every workday until CE could not detect HbCS or until 7 weeks after blood collection. The genotypes were confirmed by multiplex polymerase chain reaction.

Results

The median subject age was 27 years and 10 subjects were male. The HbCS levels were stable during the first 7 days but became undetectable in 5 cases (17.2%) after 1 week. All of them were heterozygous HbCS. Longer detection times were correlated with the higher baseline HbCS levels, with a correlation coefficient of 0.582 (P  ≤ 0.001)

Conclusion

Routine hemoglobin typing and quantitation should be performed within 1 week after blood collection to detect low HbCS levels, especially in heterozygous HbCS.

Red blood cell alloimmunization and other transfusion-related complications in patients with transfusion-dependent thalassemia: A multi-center study in Thailand

BACKGROUND

Thalassemia is a common genetic disease in Southeast Asia. Red blood cell (RBC) transfusion is an essential treatment for severe forms of thalassemia. We performed a study to demonstrate RBC alloimmunization and other transfusion-related complications in patients with transfusion-dependent thalassemia (TDT).

STUDY DESIGN AND METHODS

A multi-center web-based registry of TDT was conducted in eight medical centers across Thailand. Thalassemia information, transfusion therapy, and transfusion-related complications were collected. Factors associated with each complication were demonstrated using the logistic regression analysis.

RESULTS

Of 1000 patients recruited for the study, 449 were males (44.9%). The mean age was 23.9 ± 15.4 years. The majority of patients, 738 (73.8%) had hemoglobin E/beta-thalassemia. In the study, 421 transfusion-related complications were reported from 357 patients (35.7%). Alloimmunization was the most common complication which was found in 156 patients (15.6%) with 284 positive antibody tests. The most frequent antibodies against RBC were anti-E (80/284, 28.2%) followed by anti-Mia (45/284, 15.8%) and anti-c (32/284, 11.3%). Age ≥3 years at initial blood transfusion, splenomegaly, higher frequencies, and volumes of transfusion were significant factors associated with alloimmunization. None of the patients had to terminate blood transfusion due to multiple alloantibodies. Other commonly seen complications were allergic reactions (130, 13.0%), autoimmune hemolytic anemia (70, 7.0%) and febrile non-hemolytic transfusion reaction (54, 5.4%).

CONCLUSIONS

Transfusion-related complications, especially alloimmunization, were common among Thai patients with TDT. Extended RBC antigen-matching for the Rh system and Mia should be implemented to prevent the development of alloantibodies in multi-transfused patients.

Validation of a patient-reported outcomes symptom measure for patients with nontransfusion-dependent thalassemia (NTDT-PRO© )

This study demonstrates the quantitative characteristics of the first patient‐reported outcome (PRO) tool developed for patients with nontransfusion‐dependent β‐thalassemia (NTDT), the NTDT‐PRO^©. A multicenter validation study was performed over 24 weeks, involving 48 patients from Italy, Lebanon, Greece, and Thailand. Most patients were female (68.8%), with a median age of 34.5 years (range, 18‐52); 66.7% were diagnosed with β‐thalassemia intermedia, and median time since diagnosis was 22 years (range, 0‐43). The NTDT‐PRO comprises 6 items across 2 domains (Tiredness/Weakness and Shortness of Breath [SoB]), and was valid and reliable, with good consistency. At baseline, most patients reported symptoms as present via the NTDT‐PRO, and were highly compliant, ≥90% completing the NTDT‐PRO tool. In a pairwise correlation analysis, all items were positively correlated. Correlations between NTDT‐PRO and existing tools—36‐Item Short Form Health Survey version 2 (SF‐36v2) and Functional Assessment of Cancer Therapy‐Anemia (FACT‐An)—were assessed at weeks 1, 3, and 12; robust correlations were seen between SoB and SF‐36v2‐Vitality (r_s = −0.53), and between SoB and Fact‐An‐Fatigue Experience (r_s = −0.66) at week 1. Internal consistency was high for both Tiredness/Weakness (Cronbach alpha, 0.91) and SoB (Spearman‐Brown coefficient, 0.78); intraclass correlation coefficients were high (Tiredness/Weakness, 0.88 and 0.97; SoB, 0.92 and 0.98), demonstrating stability. Further studies are required to fully support the validity of this tool, this study demonstrated the usefulness of the NTDT‐PRO in the clinical setting and for longitudinal clinical research, particularly in trials where patient health‐related quality of life is expected to change.

Development of a patient-reported outcomes symptom measure for patients with nontransfusion-dependent thalassemia (NTDT-PRO© )

β‐Thalassemia, a hereditary blood disorder caused by reduced or absent synthesis of the β‐globin chain of hemoglobin, is characterized by ineffective erythropoiesis, and can manifest as nontransfusion‐dependent thalassemia (NTDT) or transfusion‐dependent thalassemia (TDT). Many patients with NTDT develop a wide range of serious complications that affect survival and quality of life (QoL). Patient‐reported outcomes (PRO), including health‐related QoL (HRQoL), are important tools for determining patient health impairment and selecting appropriate treatment. However, there are currently no disease‐specific PRO tools available to assess symptoms related to chronic anemia experienced by patients with NTDT. This study aimed to develop a new, US Food and Drug Administration (FDA)‐compliant PRO of chronic anemia symptoms, the NTDT‐PRO^© tool, for use in patients with NTDT. Participants had a median age of 36 years (range, 18‐47) and 60% were female. The initial development of the NTDT‐PRO tool involved concept‐elicitation interviews with 25 patients from 3 centers (in Lebanon, Greece, and Canada); subsequent interview discussions and clinical input resulted in the generation of 9 items for inclusion in the draft NTDT‐PRO. Following a round of cognitive interviews involving 21 patients from 2 centers (in Lebanon and Greece), 4 items (Pain, Headaches, Ability to Concentrate, and Paleness) were removed from the draft NTDT‐PRO. The final NTDT‐PRO comprises 6 items that measure Tiredness, Weakness, and Shortness of Breath, with or without Physical Activity. The NTDT‐PRO is a new disease‐specific HRQoL tool for patients with NTDT, developed using a thorough methodology based on FDA 2009 PRO development guidelines.

Vascular and hemostatic alterations associated with pulmonary hypertension in β-thalassemia hemoglobin E patients receiving regular transfusion and iron chelation

INTRODUCTION

Pulmonary hypertension (PH) is the commonest cardiac complication in β-thalassemia intermedia, including β-thalassemia/hemoglobin E (β-thal/HbE), and is strongly associated with splenectomy. We aimed to define the prevalence and comprehensively explore mechanisms of PH in β-thal/HbE patients receiving regular transfusion and iron chelation, which were reported to alleviate PH.

MATERIALS AND METHODS

β-Thal/HbE patients receiving regular transfusion and iron chelation over one year were enrolled. Patients at risk for PH were defined by tricuspid-regurgitant-jet-velocity (TRV) ≥ 2.5 m/s. Laboratory and echocardiographic variables were compared with healthy controls.

RESULTS

There were 68 β-thal/HbE, including 31 (45.6%) splenectomized patients, and 38 controls included for analysis. PH was detected in 29 β-thal/HbE (42.6%). β-Thal/HbE with PH had a significant reduction in nitric oxide metabolites (NOx) but elevations in thrombin-antithrombin (TAT) complex, soluble thrombomodulin (sTM), endothelin-1 (ET-1) and flow-mediated dilation (FMD) values compared to those without PH (all, p < 0.05). TRV was significantly correlated with NOx, TAT, sTM, ET-1 and FMD values (r = -0.514, r = 0.281, r = 0.313, r = 0.245 and r = -0.474; all p < 0.05). Erythropoietic activity, serum ferritin, circulating total tissue factor (TF) antigen, microparticle-associated TF activity, microparticle's procoagulant activity and soluble p-selectin levels were not different between PH and non-PH subgroups. Notably, there were no significant associations between splenectomy and PH.

CONCLUSIONS

PH remains prevalent in β-thal/HbE patients receiving long-term transfusion and iron chelation. PH is not associated with splenectomy status but correlated with NO depletion, TF-independent hypercoagulability and endothelial perturbation.

The first validated criteria for effective screening and a new simplified method for α-globin gene sequencing for diagnosis of uncommon α-globin mutations

No well-defined phenotypes that distinguish between unknown α- and β-globin mutations have been reported to date. Direct DNA sequencing of α-globin genes can be technically challenging, as α1- and α2-globin genes are nearly indistinguishable. To detect hemoglobin variants (HbXs) on Hb analysis, the entire β- and α-globin genes were directly sequenced using a newly developed sequencing protocol for α-globin genes. An algorithm to distinguish between α- and β-HbXs was constructed and subsequently validated in the independent validation group. Distinctive characteristics that can distinguish 39 α-HbXs from 24 β-HbXs were the presence of unidentifiable variants of HbA₂ and/or HbX of <37% on isoelectric focusing and <31% on high-performance liquid chromatography. Another set of 67 HbXs was employed to validate our algorithm. This accurately predicted 33 α-HbXs with 100% sensitivity and 97.1% specificity. Our sequencing protocol for α-globin genes was able to identify 11 rare mutations among all exons of both α-globin genes from 72 subjects. Six of these variants were first discovered in Thais. This is the first well-characterized algorithm for distinguishing unknown Hb variants in a large cohort. Our validated criteria and DNA sequencing procedure are highly efficient for molecular characterization of rare Hb mutations.

Limitations of serum ferritin to predict liver iron concentration responses to deferasirox therapy in patients with transfusion-dependent thalassaemia

BACKGROUND

In transfusion-dependent anaemias, while absolute serum ferritin levels broadly correlate with liver iron concentration (LIC), relationships between trends in these variables are unclear. These relationships are important because serum ferritin changes are often used to adjust or switch chelation regimens when liver magnetic resonance imaging (MRI) is unavailable.

OBJECTIVES AND METHODS

This post hoc analysis of the EPIC study compared serum ferritin and LIC in 317 patients with transfusion-dependent thalassaemia before and after 1 yr of deferasirox.

RESULTS

Serum ferritin responses (decreases) occurred in 73% of patients, 80% of whom also have decreased LIC. However, 52% of patients without a serum ferritin response did decrease LIC and by >1 mg Fe/g dw (median 3.9) in 77% of cases. Absolute serum ferritin and LIC values correlated significantly only when serum ferritin was <4000 ng/mL (r = 0.59; P < 0.0001) and not at higher levels (≥4000 ng/mL; r = 0.19). Serum ferritin response was accompanied by decreased LIC in 89% and 70% of cases when serum ferritin was <4000 or ≥4000 ng/mL, respectively.

CONCLUSIONS

As serum ferritin non-response was associated with LIC decrease in over half of patients, use of liver MRI may be particularly useful for differentiating true from apparent non-responders to deferasirox based on serum ferritin trends alone.

Defining serum ferritin thresholds to predict clinically relevant liver iron concentrations for guiding deferasirox therapy when MRI is unavailable in patients with non-transfusion-dependent thalassaemia

Liver iron concentration (LIC) assessment by magnetic resonance imaging (MRI) remains the gold standard to diagnose iron overload and guide iron chelation therapy in patients with non-transfusion-dependent thalassaemia (NTDT). However, limited access to MRI technology and expertise worldwide makes it practical to also use serum ferritin assessments. The THALASSA (assessment of Exjade(®) in non-transfusion-dependent THALASSemiA patients) study assessed the efficacy and safety of deferasirox in iron-overloaded NTDT patients and provided a large data set to allow exploration of the relationship between LIC and serum ferritin. Using data from screened patients and those treated with deferasirox for up to 2 years, we identified clinically relevant serum ferritin thresholds (for when MRI is unavailable) for the initiation of chelation therapy (>800 μg/l), as well as thresholds to guide chelator dose interruption (<300 μg/l) and dose escalation (>2000 μg/l). (clinicaltrials.gov identifier: NCT00873041).

Approaching low liver iron burden in chelated patients with non-transfusion-dependent thalassemia: the safety profile of deferasirox

OBJECTIVE

Patients with non-transfusion-dependent thalassemia (NTDT) often develop iron overload and related complications, and may require iron chelation. However, the risk of over-chelation emerges as patients reach low, near-normal body iron levels and dose adjustments may be needed. In the THALASSA study, the threshold for chelation interruption was LIC <3 mg Fe/g dw (LIC<3); 24 patients receiving deferasirox for up to 2 yr reached this target. A post hoc analysis was performed to characterize the safety profile of deferasirox as these patients approached LIC<3.

METHODS

THALASSA was a randomized, double-blind, placebo-controlled study of two deferasirox regimens (5 and 10 mg/kg/d) versus placebo in patients with NTDT. Patients randomized to deferasirox or placebo in the core could enter a 1-yr extension, with all patients receiving deferasirox (extension starting doses based on LIC at end-of-core and prior chelation response). The deferasirox safety profile was assessed between baseline and 6 months before reaching LIC<3 (Period 1), and the 6 months immediately before achieving LIC<3 (Period 2).

RESULTS

Mean ± SD deferasirox treatment duration up to reaching LIC<3 was 476 ± 207 d, and deferasirox dose was 9.7 ± 3.0 mg/kg/d. The exposure-adjusted AE incidence regardless of causality was similar in periods 1 (1.026) and 2 (1.012). There were no clinically relevant differences in renal and hepatic laboratory parameters measured close to the time of LIC<3 compared with measurements near the previous LIC assessment.

CONCLUSIONS

The deferasirox safety profile remained consistent as patients approached the chelation interruption target, indicating that, with appropriate monitoring and dose adjustments in relation to iron load, low iron burdens may be reached with deferasirox with minimal risk of over-chelation.

Deferasirox effectively reduces iron overload in non-transfusion-dependent thalassemia (NTDT) patients: 1-year extension results from the THALASSA study

Patients with non-transfusion-dependent thalassemia (NTDT) often develop iron overload that requires chelation to levels below the threshold associated with complications. This can take several years in patients with high iron burden, highlighting the value of long-term chelation data. Here, we report the 1-year extension of the THALASSA trial assessing deferasirox in NTDT; patients continued with deferasirox or crossed from placebo to deferasirox. Of 133 patients entering extension, 130 completed. Liver iron concentration (LIC) continued to decrease with deferasirox over 2 years; mean change was −7.14 mg Fe/g dry weight (dw) (mean dose 9.8 ± 3.6 mg/kg/day). In patients originally randomized to placebo, whose LIC had increased by the end of the core study, LIC decreased in the extension with deferasirox with a mean change of −6.66 mg Fe/g dw (baseline to month 24; mean dose in extension 13.7 ± 4.6 mg/kg/day). Of 166 patients enrolled, 64 (38.6 %) and 24 (14.5 %) patients achieved LIC <5 and <3 mg Fe/g dw by the end of the study, respectively. Mean LIC reduction was greatest in patients with the highest pretreatment LIC. Deferasirox progressively decreases iron overload over 2 years in NTDT patients with both low and high LIC. Safety profile of deferasirox over 2 years was consistent with that in the core study.

Deferasirox demonstrates a dose-dependent reduction in liver iron concentration and consistent efficacy across subgroups of non-transfusion-dependent thalassemia patients

The 1-year THALASSA study enrolled 166 patients with various non-transfusion-dependent thalassemia (NTDT) syndromes, degrees of iron burden and patient characteristics, and demonstrated the overall efficacy and safety of deferasirox in reducing liver iron concentration (LIC) in these patients. Here, reduction in LIC with deferasirox 5 and 10 mg/kg/day starting dose groups is shown to be consistent across the following patient subgroups—baseline LIC/serum ferritin, age, gender, race, splenectomy (yes/no), and underlying NTDT syndrome (β-thalassemia intermedia, HbE/β-thalassemia or α-thalassemia). These analyses also evaluated deferasirox dosing strategies for patients with NTDT. Greater reductions in LIC were achieved in patients dose-escalated at Week 24 from deferasirox 10 mg/kg/day starting dose to 20 mg/kg/day. Patients who received an average actual dose of deferasirox >12.5–≤17.5 mg/kg/day achieved a greater LIC decrease compared with the ≥7.5–≤12.5 mg/kg/day and >0–<7.5 mg/kg/day subgroups, demonstrating a dose–response efficacy. LIC reduction across patient subgroups was generally consistent with the primary efficacy analysis with a similar safety profile. Am. J. Hematol. 88:503–506, 2013. © 2013 Wiley Periodicals, Inc.

Efficacy and safety of deferasirox at low and high iron burdens: results from the EPIC magnetic resonance imaging substudy

The effect of deferasirox dosing tailored for iron burden and iron loading based on liver iron concentration (LIC) was assessed over 1 year in less versus more heavily iron-overloaded patients in a substudy of the Evaluation of Patients' Iron Chelation with Exjade®. Deferasirox starting dose was 10-30 mg/kg/day, depending on blood transfusion frequency, with recommended dose adjustments every 3 months. Therapeutic goals were LIC maintenance or reduction in patients with baseline LIC <7 or ≥7 mg Fe/g dry weight (dw), respectively. Changes in LIC (R2-magnetic resonance imaging) and serum ferritin after 1 year were assessed. Adverse events (AEs) and laboratory parameters were monitored throughout. Of 374 patients, 71 and 303 had baseline LIC <7 and ≥7 mg Fe/g dw, respectively; mean deferasirox doses were 20.7 and 27.1 mg/kg/day (overall average time to dose increase, 24 weeks). At 1 year, mean LIC and median serum ferritin levels were maintained in the low-iron cohort (-0.02 ± 2.4 mg Fe/g dw, -57 ng/mL; P = not significant) and significantly decreased in the high-iron cohort (-6.1 ± 9.1 mg Fe/g dw, -830 ng/mL; P < 0.0001). Drug-related gastrointestinal AEs, mostly mild to moderate, were more frequently reported in the <7 versus ≥7 mg Fe/g dw cohort (39.4 versus 20.8 %; P = 0.001) and were not confounded by diagnosis, dosing, ethnicity, or hepatitis B and/or C history. Reported serum creatinine increases did not increase in low- versus high-iron cohort patients. Deferasirox doses of 20 mg/kg/day maintained LIC <7 mg Fe/g dw and doses of 30 mg/kg/day were required for net iron reduction in the high-iron cohort, with clinically manageable safety profiles. The higher incidence of gastrointestinal AEs at lower iron burdens requires further investigation.

Risk factors for symptomatic venous thromboembolism in Thai hospitalised medical patients

Thromboprophylaxis for venous thromboembolism (VTE) failed to reduce overall mortality in hospitalised medical patients. As a VTE prediction model for Asians is still lacking, this study aimed to identify very high risk patients who would be the main target for prevention. In 2009, medical patients admitted to King Chulalongkorn Memorial hospital, a tertiary care centre, were prospectively evaluated for risk factors. The high-risk cohort was monitored for symptomatic VTE until six weeks after discharge. No heparin prophylaxis was given. Of 1,290 high-risk patients, 27 (2.1%, 95% confidence interval [CI] 1.3-2.9) developed proven VTE, 25.9% of which were diagnosed after discharge. Cases with VTE stayed longer in the hospital (median 18 vs. 11 days, p < 0.001). The significant risk factors in a multivariate analysis were autoimmune disease, solid tumours, family history of VTE, varicose vein and oestrogen with the relative risks of 11.8, 4.7, 120.3, 40.1 and 17.1 (p < 0.001, 0.001, 0.001, 0.002 and 0.038), respectively. Either autoimmune disease or solid tumours were found in 63% of VTE with the relative risk of 4.5 (95% CI 2.1-9.7, p < 0.001). In contrast, previously reported VTE scores in western patients could not stratify the VTE risks, but all the scores predicted higher mortality. In conclusion, VTE is common in Asian hospitalised medical patients. Patients with autoimmune disease and those with solid tumours are highly susceptible to VTE. A prophylactic strategy in these groups is required.

Severe beta(0) thalassemia/hemoglobin E disease caused by de novo 22-base pair duplication in the paternal allele of beta globin gene

beta Thalassemia is a major public health concern in Southeast Asia. A prevention program has been implemented in Thailand comprising mass carrier screening and genetic testing. In this study, a Thai girl with severe beta thalassemia/hemoglobin (Hb) E disease was born from the mother with Hb E trait and the genotypically normal father. DNA sequencing revealed novel 22-bp tandem duplication in the paternal allele of beta globin gene, producing a severely truncated product. A short recurring nucleotide at the insertion site suggested a predisposition to this mutation. Therefore, spontaneous beta globin mutations occasionally occur in normal population. Its clinical significance is noteworthy in countries with high prevalence of beta thalassemia.

Mantle cell lymphoma in Thai patients

Mantle cell lymphoma (MCL) is a disease entity recently introduced into the new lymphoma classification, therefore, the clinical features as well as therapeutic outcomes in Thai patients with MCL has never been described The authors herein retrospectively analysed 21 newly diagnosed patients with MCL at King Chulalongkorn Memorial Hospital from January 1997 to December 2002. The median age of the patients was 54 years (range, 38-79). Male:female was 4:1. Generalized lymphadenopathy (67%) was the most common presenting feature. The majority of patients (85%) had advanced disease (stage III, IV, Ann Arbor system). Fifty-six percent of the patients were classified as the high- and high-intermediate risk group by the international prognostic index. Most patients were treated with CHOP (vincristine, cyclophosphamide, doxorubicin, prednisolone) or CVP (vincristine, cyclophosphamide, prednisolone) regimen. The overall complete remission rate was 59%. With a median follow-up of 13 months (range, 1-62 months), the rates of overall, progression-free and disease-free survivals were 32%, 9% and 20%, respectively. Sixty-seven percent of the patients had relapse/progressive disease after follow-up. In conclusion, the clinical features as well as the outcomes of Thai patients with MCL were comparable to patients in Western countries. Newly diagnosed patients should be treated with novel modalities other than conventional CHOP chemotherapy in order to improve the outcomes.

Evaluation of automated glycohemoglobin analyzer HLC-723G7 beta-thalassemia analysis mode

We evaluated the new automated glycohemoglobin analyzer HLC-723G7 (G7) intended for beta-thalassemia diagnosis to determine correlation of hemoglobin (Hb) F and Hb A2 quantitation with the Variant beta-Thalassemia Short Program and to evaluate the performance of the G7 analyzer. Two hundred fifty EDTA blood samples with Hb A, A2, and F by Variant were analyzed for Hb A2 and Hb F by G7 device. Recovery, precision, and interference of the G7 analyzer were studied. The R2 values for Hb A2 and Hb F were 0.963 and 0.640, respectively. Recovery of Hb A2 and Hb F of low and high control samples ranged from 96% to 100% and 91% to 101%, respectively. The coefficients of variation (CVs) of intraassay precision ranged from 1.3% to 3.9% for Hb F and 0.0 to 1.9% for Hb A2. The CVs of interassay precision ranged from 1.9% to 5.6% for Hb F and 2.5% to 3.0% for Hb A2. The CVs for Hb F in both conjugated bilirubin and chyle substance groups were higher than the CVs for Hb A2. This evaluation revealed very good correlation of Hb A2 measurement between the G7 and the Variant devices. The performance evaluation demonstrated good recovery, precision, and low interference of both Hb A2 and Hb F measurements.

Prognostic significance of the immunophenotype versus the International Prognostic Index in aggressive non-Hodgkin's lymphoma

The International Prognostic Index (IPI) is currently the most widely accepted prognostic factor system for patients with aggressive non-Hodgkin's lymphoma (NHL). However, in constructing the model, the immunophenotype of the disease was not used as an independent variable. The purpose of the present study was to assess and compare the prognostic significance of the immunophenotype (B-cell vs. T-cell) of aggressive NHL with other well-established prognostic determinants, in particular the IPI. Between January 1995 and December 2000, a retrospective analysis was conducted of clinical and pathological data on 181 patients aged = 15 years who had been newly diagnosed with aggressive NHL. All pathology slides were reviewed and defined according to the Revised European-American Lymphoma classification. Forty-one patients (23%) had T-cell lymphoma and 140 patients (77%) had B-cell lymphoma. Diffuse large B-cell lymphoma and unspecified peripheral T-cell lymphoma were the 2 most common entities, comprising 63% and 14% of patients, respectively. Most of the pretreatment characteristics, including IPI risk groups, were not significantly different between B-cell and T-cell lymphomas. The rates of complete remission (71% vs. 54%, P = 0.038) and progressive disease (39% vs. 63%, P = 0.023) significantly favored patients with B-cell lymphoma. With a median follow-up time of 31 months (range, 10-81 months), the 5-year overall survival (49% vs. 27%; P < 0.001) and event-free survival (35% vs. 10%; P < 0.001) were significantly better in B-cell lymphoma. The 5-year disease-free survival was also in favor of the B-cell group (48% vs. 21%; P = 0.086). Patients with T-cell lymphoma yielded inferior survival in all IPI risk groups. Multivariate analysis revealed T-cell lymphoma as the most significant factor associated with short overall survival (relative risk [RR], 3.4; 95% CI, 1.9-5.9) and event-free survival (RR 2.7, 95% CI, 1.7-4.3). When a second multivariate analysis was done using IPI (age, stage, performance status, number of extranodal sites, and serum lactate dehydrogenase) as one independent variable, T-cell phenotype remained the strongest factor affecting the survival of patients (P < 0.001). T-cell lymphoma is an independent prognostic factor, the significance of which is at least comparable to the IPI for patients with aggressive NHL.

Experience with continuous infusion of recombinant activated factor VII in the Asia-Pacific region

There is increasing interest in continuous infusion of recombinant activated factor VII (rFVIIa) as a convenient and safe alternative to intermittent bolus therapy. In the Australian patients reported in this paper, cost savings of up to 25% in the first 12 h of treatment with continuous infusion of rFVIIa have been achieved safely, suggesting that substantial overall savings are possible. However, in the Thai patient reported, a dose reduction of 35% in the first 12 h was associated with poor haemostatic control, suggesting that a dose reduction of >25% may be inadvisable. The indications for treatment in the five Australian patients were: retroperitoneal haemorrhage (n = 3); right forearm compartment syndrome (n = 1); wrist haemarthrosis and median nerve compression (n = 2); sublingual haematoma (n = 1); and cerebral (mid-brain) haemorrhage (n = 1). Treatment was effective in four out of five patients (six bleeding episodes) and there was one treatment failure where treatment had been substantially delayed. The Thai patient was treated as part of a prospective, uncontrolled, observational study of 34 bleeding episodes in 22 patients in the Asia-Pacific region. Treatment was judged ineffective after 24 h, but full haemostatic control was subsequently achieved with intermittent rFVIIa therapy.

A predictive model for life-threatening neutropenia and febrile neutropenia after the first course of CHOP chemotherapy in patients with aggressive non-Hodgkin's lymphoma

The purpose of this study was to develop a model for predicting the occurrence of life-threatening neutropenia (LN, ANC < or = 0.5 x 10(9)/l) and febrile neutropenia (FN, an ANC < 0.5x10(9)/l in association with a body temperature of > or = 38.3 degrees C) after the first cycle of CHOP therapy in patients newly diagnosed with aggressive NHL. One hundred and forty-five patients, aged > or = 15 years, with newly diagnosed diffuse mixed, diffuse large-cell or large-cell immunoblastic lymphoma (IWF categories, F, G, H), who had been treated with CHOP at King Chulalongkorn Memorial Hospital between June 1994 and December 1998, were entered into the study. The criteria for eligibility included complete work-up for baseline evaluation, treatment with standard CHOP chemotherapy, at least one complete blood count performed during days 8-14 post-treatment or if at any time the patients experienced a BT of > or = 38.3 degrees C and were not treated with any colony-stimulating factors (CSFs). The median age of the patients was 47 years (range, 17-78). Forty-eight percent of the patients were in stage III/IV, 36% had ECOG performance status (PS) II-IV, 30% had > or = 2 extranodal diseases, 59% had serum LDH > 1 x normal and 23% had bone marrow involvement. The frequencies of patients in the low-, low-intermediate, high-intermediate and high risk groups according to the international index were 29%, 28%, 17% and 26%, respectively. Thirty-nine percent of the patients had LN at nadir and 33% developed FN after the first course of CHOP. By using stepwise logistic regression analysis, the pretreatment variables independently predictive of the LN at nadir and the FN were serum albumin concentration of < or = 3.5 g/dl, serum LDH > 1 x normal and whether there was bone marrow involvement of lymphoma at presentation. The model, based on the incorporation of these three factors, identified three risk groups of patients with a predicted probability of developing LN at nadir of 81.5% (95% CI, 68.5-90.7) (high risk), 23.9% (95% CI, 12.6-38.8) (intermediate risk) and 4.4% (95% CI, 0.5-15.1) (low risk). The predicted rate of FN in the three groups were 72.2% (95% CI, 58.4-83.5), 17.4% (95% CI, 7.8-31.4) and 2.2% (95% CI, 0.05-11.8), respectively. In conclusion, our model could be used as a means to identify patients with newly diagnosed aggressive NHL, treated with CHOP, who are at high risk (> or = 50% probability) of developing post-first course LN and FN, in whom CSF and/or antibiotic prophylaxis might be indicated.

Prognostic factors of green pit viper bites

Clinical features of green pit viper bites vary from asymptomatic to fatal bleeding. Antivenin promptly reverses the coagulopathy but has considerable adverse side effects. In this study, potential clinical predictors of severe outcomes (wound necrosis, wound infection, and systemic bleeding) and antivenin allergy were determined in 271 moderate to severe cases of green pit viper bites by multivariate analysis. The incidences of systemic bleeding, wound necrosis, secondary infection, and antivenin allergy were 17.3%, 6.6%, 5.5%, and 20.8% respectively. The predictors of systemic bleeding were the combination of thrombocytopenia and prolonged venous clotting time and bite sites away from digits. A bite on the fingers or toes was a risk factor for skin necrosis (P = 0.03). Systemic absorption of the venom from digits may be poor, resulting in severe local but mild systemic effects. The presence of blisters often led to necrosis and secondary infections (P = 0.0037 and P = 0.0006, respectively). Although negative skin test results do not exclude the possibility of antivenin allergy, positive results indicate a high risk (P = 0.016) requiring special precautions.

Advances in molecular diagnosis of inherited hemoglobin disorders

Molecular diagnosis for inherited disorders of hemoglobin production has been driven largely by the need for improved prenatal diagnosis. In turn, DNA-based testing has engendered better methods of fetal sampling. The sensitivity of DNA-based testing was increased tremendously by the polymerase chain reaction. Currently there are numerous polymerase chain reaction-based methods for diagnosing specific mutant globin alleles and detecting unknown mutations. These rely on restriction analysis, allele-specific hybridization or amplification, alterations in electrophoretic mobility, and DNA sequence analysis. The advantages and disadvantages of each are important to their specific application. The reverse dot blot method, with its capability for screening multiple alleles with a single hybridization reaction, is currently the most advantageous method for prenatal and routine clinical diagnosis.

Reverse dot-blot detection of the African-American beta-thalassemia mutations

DNA-based diagnosis of the beta thalassemias provides accuracy to newborn screening genetic counseling, and prenatal diagnosis. However, the use of polymerase chain reaction (PCR)-based methods is challenged by the great number of different-beta-thalassemia mutations that exist even within defined ethnic groups. In this regard, the reverse dot-blot method offers a means of screening for several mutations with a single hybridization reaction. We have applied the reverse dot-blot method to the detection of the beta-thalassemia mutations of African-Americans. We used two biotin-labeled primer pairs in a duplex reaction to amplify and label two beta-globin target DNA fragments that encompass all known African-American beta-thalassemia mutations. The PCR products were denatured and hybridized to polyT-tailed, membrane-fixed, allele-specific probe pairs for the hemoglobin (Hb) S, Hb C, and 14 beta-thalassemia mutations and their corresponding wild-type sequences. Seven common mutations plus Hb S and Hb C were included on one diagnostic strip, and seven less common beta-thalassemia mutations were included on another strip. Carefully controlled, high stringency hybridization allowed accurate distinction of these alleles. Reverse dot-blot diagnosis of the less common beta-thalassemia mutations precludes the need for alternative, more technically challenging methods. This method provides a rapid, accurate method for diagnosis of beta thalassemia among African-Americans and other ethnic groups in which beta thalassemia occurs.

Reverse dot-blot detection of Thai beta-thalassaemia mutations

Pending curative therapy, newborn screening and prenatal diagnosis are essential to the management of beta thalassaemia. Diagnosis using electrophoretic methods is difficult in the presence of composite phenotypes and high Hb F levels. Direct DNA detection of mutant alleles circumvents both problems, but the enormous diversity of beta-thalassaemia mutations poses challenges for this approach. Among PCR-based tests, the reverse dot-blot method enables screening several mutations with a single hybridization reaction. Unfortunately it has often been targeted to only the common mutations of a particular ethnic population, necessitating the use of more arduous detection methods for the less common mutations. We developed a reverse dot-blot strip for the 10 beta-thalassaemia mutations, including the beta-thalassaemic haemoglobinopathies Hb E and Hb Malay, that account for 96% of beta thalassaemia in Thailand, and another strip for six less common Thai mutations. The second strip precludes the need for more technically challenging methods. To avoid problems associated with secondary structure of amplified full-length target DNA, we amplified and labelled beta-globin DNA as two shorter fragments that encompassed all known Thai mutations. Reverse dot-blotting is a rapid, accurate method for detecting beta-thalassaemia mutations.