Low-dose prophylaxis and its impact on the health of haemophilia patients.

BACKGROUND AND OBJECTIVES: There is convincing evidence to show that low-dose prophylaxis (LDP) results in reduction in annualized bleeding rate (ABR) and better health-related quality of life (HRQoL) compared with on-demand or episodic treatment (ET) in haemophilia patients. The aim is to review various LDP protocols practised for the treatment of haemophilia, specifically in resource-limited countries. METHODS: A literature survey was made of articles published in English language in PubMed and EMBASE without any time limit using keywords 'low dose', 'prophylaxis' and 'haemophilia' in different combinations. RESULTS: A total of 19 reports involving LDP in patients with haemophilia were included in this review. Almost all studies reported reduction in ABR, improvement in joint function, pain and HRQoL compared with ET, but this did not fully translate into significant improvement in structural arthropathy already caused by earlier bleeds, suggesting that LDP may be less or ineffective in either stopping or reversing the damage. Individualized dose escalation protocols based on pharmacokinetic (PK) or clinical parameters were found to be superior to fixed LDP protocols and cost-effective compared with standard dose protocols. CONCLUSION: The developing countries can initiate LDP as the first step of prophylaxis, but certainly this should not be the final goal of the health care system in any country. Due to the complex pathophysiological mechanisms underlying haemophilic arthropathy, long-term data on LDP in haemophilia patients are warranted.

Differential response to FEIBA is strongly associated with the prothrombotic microparticles.

BACKGROUND: Treatment of patients with hemophilia with an inhibitor is generally done using bypassing agents (BPA), wherein variability in response is observed. Due to lack of validated laboratory assays, monitoring is being carried out by clinical response only. Emerging biomarkers like procoagulant microparticles (MPs) may prove to be promising. AIM: To analyze whether procoagulant MP levels correlate with clinical response to FEIBA therapy. MATERIALS AND METHODS: Total phosphatidylserine (PS) expressing MPs along with different cell derived MPs were measured in blood samples obtained prior and 2 hour post-FEIBA infusion in 64 bleeding episodes associated with 43 severe hemophilia patients. RESULTS AND DISCUSSION: Patients with excellent response showed statistically significant increase in %MP of PS-MPs (p < 0.0001; 95.0% CI Range: -64.33 to -24.42) when compared to those with moderate response; platelet %MP change was also found significantly associated (p < 0.05) with clinical response. In search of an assay for monitoring FEIBA, results though preliminary seem to be promising with increase in %PS-MP correlating well with the clinical response. Coagulation being multifactorial process involves multiple factors for balanced hemostasis, which needs to be accounted. Larger studies in this line may provide indications for usage of MPs as monitoring and dose adjustment tool of FEIBA therapy.

Multiple Heritable and Acquired Risk Factors in a Case of Recurrent Retinal Vein Occlusion.

A 40 year old female presented with branch retinal vein occlusion in the right eye followed by a second episode, a year later, of central retinal vein occlusion in the left eye. The patient was found to be heterozygous for factor V Leiden and factor V HR2 haplotype G5380A. She had a history of use of oral contraceptives, had reduced levels of tissue plasminogen activator, positive for lupus anticoagulant and diagnosed with hypertension post second episode of RVO. Presence of both heritable and acquired thrombophilia along with hypofibrinolysis induced by reduced levels of tissue plasminogen activator might have led to the recurrence of retinal vein occlusion in this patient. This case illustrates the contribution of multiple hereditary and acquired risk factors in the clinical manifestation of recurrent retinal vein occlusion thereby warranting the application of a more thorough work-up in such cases. The case also briefly touches on the fact that treatment for every RVO cannot be the same and should be decided by taking into consideration the associated risk factors.

Dysfunctional fibrinolysis and cerebral venous thrombosis.

Cerebral venous thrombosis (CVT) is an uncommon neurological disease with high morbidity and mortality. Even after extensive thrombophilia screening, majority of the thrombosis cases remain with unknown etiology. Hypofibrinolysis due to acquired or congenital deficiencies or abnormalities in factors in the fibrinolytic cascade is a known cause of thrombosis at any site. In the present study 104 cases of radiologically confirmed CVT cases were investigated for the conventional thrombophilia along with factors in the fibrinolytic cascade to find a possible etiology for the clinical manifestation. Conventional thrombophilia markers which included PC, PS, AT and FVL mutation were detected in 16.3% of the patients. Approximately 19% cases had grossly elevated plasma PAI-1 levels. PAI-1 4G/4G genotype was found to be strongly associated with high PAI-1 levels. 2.9% cases had reduced tPA levels, 1.9% had plasminogen deficiency and 1.9% cases had increased alpha-2-antiplasmin levels. Along with conventional thrombophilia, dysfunctional fibrinolysis is found to be strongly associated with CVT. Understanding the role of risk factors is important for appropriate treatment of this serious disorder.

A novel homozygous frameshift mutation in Exon 7 of the ADAMTS13 gene in a patient with congenital thrombotic thrombocytopenic purpura from India: a case report.

BACKGROUND: Thrombotic thrombocytopenia purpura (TTP) is a rare and life-threatening thrombotic microangiopathy characterized by thrombocytopenia and microangiopathic hemolytic anemia. It is caused by deficiency of ADAMTS13 metalloprotease, which cleaves ultra-large von Willebrand factor into smaller functional units. TTP may be congenital or acquired, and the congenital form is caused by inherited mutations in the ADAMTS13 gene, leading to deficiency of protein or reduced protein activity. CASE REPORT: We report a 5-year-old male patient who manifested with thrombocytopenia and microangiopathic hemolytic anemia at the age of 1 year. CONCLUSION: ADAMTS13 activity in the patient was below 5%, and ADAMTS13 antibody was absent. Subsequent genetic analysis of the ADAMTS13 gene revealed a novel homozygous mutation (i.e., frameshift insertion mutation A237GfsX153 [c.708_709insG] in Exon 7 of ADAMTS13). Both parents were heterozygous for this mutation.

Investigation of Plasminogen Activator Inhibitor-1 (PAI-1) 4G/5G promoter polymorphism in Indian venous thrombosis patients: A case-control study.

BACKGROUND: The role of PAI-1 4G/5G polymorphism in venous thrombosis has been contradictory. PAI-1 4G/4G genotype is associated with elevated levels of PAI-1 resulting in a hypofibrinolytic state and a higher thrombotic risk. OBJECTIVE: In this study, the distribution of genotypes and frequency of alleles of the 4G/5G polymorphism of PAI-1 gene in Indian patients with different types of venous thrombosis was investigated for its role in development of thrombosis. METHOD: A total of 87 portal vein thrombosis (PVT), 71 Budd-Chiari syndrome (BCS), 156 cerebral vein thrombosis (CVT), and 163 deep vein thrombosis (DVT) patients were studied alongside 251 healthy controls for the PAI-1 4G/5G polymorphism by allele-specific PCR. RESULTS: Frequency of 4G/4G genotype was higher in all groups in comparison with controls. 4G/4G was associated with PVT risk (OR=2.51, 95% CI=1.29-4.96, P=.0075), BCS risk (OR=5.98, 95% CI=2.68-13.42, P<.0001), and DVT risk (OR=1.75, 95% CI=0.98-3.02, P=.0225). This is the first case-control study from India establishing PAI-1 4G/4G as a strong risk factor for abdominal thrombosis (PVT and BCS). Statistically significant association was not found between 4G/4G genotype and CVT risk. CONCLUSION: PAI-1 4G/4G is a strong risk factor for venous thrombosis in Indian patients and should be included in laboratory testing panel of thrombophilia.

Genetic basis of severe factor XIII deficiency in a large cohort of Indian patients: Identification of fourteen novel mutations.

Congenital factor XIII (FXIII) deficiency, the most under diagnosed disorder is caused mainly due to underlying defects in the catalytic A subunit of FXIII. More than 100 mutations throughout the factor XIII A gene (F13A1) have been identified so far. Present study aims to characterize the molecular basis of severe congenital FXIII deficiency in a large series of patients from different parts of India. F13A1 defects were identified in 37 severe FXIII deficient unrelated Indian patients by direct DNA sequencing. 25 mutations were detected, of which 10 were missense, 9 nonsense, 3 splice site and 3 deletions; 14 were novel. This is the largest series of FXIII deficient cases reported from India in which mutations were analysed with high heterogeneity in the nature of mutations along with several common mutations.

Bengal macrothrombocytopenia is not totally an innocuous condition.

Inherited macrothrombocytopenia is a subgroup of thrombocytopenias, and is characterised by the presence of giant platelets and decreased platelet count with variable bleeding manifestations. Bengal macrothrombocytopenia is a newly described entity, previously called asymptomatic constitutional macrothrombocytopenia (ACMT), presented with variable bleeding tendencies; with mild to severe thrombocytopenia and macro-platelets in their peripheral blood smear and it is not totally an innocuous condition as described previously.

A simple clot based assay for detection of procoagulant cell-derived microparticles.

BACKGROUND: Cell-derived microparticles (MPs) are important biomarkers in many facets of medicine. However, the MP detection methods used till date are costly and time consuming. The main aim of this study was to standardize an in-house clot based screening method for MP detection which would not only be specific and sensitive, but also inexpensive. METHODS: Four different methods of MP assessment were performed and the results correlated. Using the flow cytometry technique as the gold standard, 25 samples with normal phosphatidylserine (PS) expressing MP levels and 25 samples with elevated levels were selected, which was cross checked by the commercial STA Procoag PPL clotting time (CT) assay. A simple recalcification time and an in-house clot assay were the remaining two tests. The in-house test measures the CT after the addition of calcium chloride to MP rich plasma, following incubation with Russell viper venom and phospholipid free plasma. RESULTS: The CT obtained by the in-house assay significantly correlated with the results obtained by flow cytometry (R2=0.87, p<0.01). CONCLUSIONS: Though preliminary, the in-house assay seems to be efficient, inexpensive and promising. It could definitely be utilized routinely for procoagulant MP assessment in various clinical settings.

Challenges and open issues in the management of acquired hemophilia A (AHA).

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by antibodies which neutralize the function of factor VIII (FVIII). The disease presents a complex clinical challenge to the treating Physicians and Hematologists. As the disease is associated with high mortality, prompt management is necessary. Early recognition, quick diagnosis and timely referral to a specialized center are important for better management of these patients. The different clinical manifestations, underlying pathology, inhibitor kinetics and the associated age related comorbidities do not allow extrapolation of the treatment protocols of congenital hemophilia to AHA. The basic strategies of the management of AHA patients involve maintaining hemostasis, suppression or eradication of antibodies, diagnosis and treatment of underlying pathology and avoid treatment related complications like thrombosis. The efficiency of hemostatic agents which are generally used to treat AHA is unpredictable. Due to the rarity of the disease, there are no randomized clinical trials on the management of this disorder and thus the expertise and experience of the treating Physicians' guide treatment strategies.

Differential expression of genes involved in Bengal macrothrombocytopenia (BMTCP).

Bengal macrothrombocytopenia (BMTCP) is a giant platelet disorder with mild to moderate thrombocytopenia, clinically characterized by mild bleeding symptoms to totally asymptomatic condition. The pathophysiological mechanism of this condition is not fully understood yet. In the present study, 5 subjects (P1-P5) with BMTCP whose platelet counts ranged between 36140X10(9)/l and mean platelet volume (MPV)13.5-16.1fl were analyzed for differential gene expression of platelets by suppressive subtractive hybridization (SSH) technique. Four genes i.e. myotubularin related protein 9 (MTMR9), iron responsive element binding protein 2 (IREB2), alpha tubulin(TUBA) and tyrosine kinase ligand (TKL) were found to be differentially expressed in patient platelets as compared to that of normal healthy controls which was further confirmed by quantitative RT PCR analysis. The study highlights a multi-factorial etiology for BMTCP which is widely prevalent in the northeastern region of the Indian subcontinent.

Inherited and acquired thrombophilia in Indian women experiencing unexplained recurrent pregnancy loss.

The most frequently hypothesized cause of unexplained recurrent pregnancy loss (RPL) refers to a defective maternal haemostatic response leading to uteroplacental thrombosis. Approximately 20% women suffering from pregnancy loss (PL) are associated with autoimmune disorders and more than 50% remain idiopathic after common traditional investigations. The present study aims to investigate the prevalence of different genetic and acquired thrombophilia markers in a large series of Indian women with RPL. Such studies will help analyze the markers which pose maximum risk and help in the appropriate treatment in subsequent pregnancies. The study comprised of 587 women with no apparent etiological causes of RPL and 115 healthy women controls. p values were calculated with two tailed Fisher's exact test; statistical significance was assumed at p<0.05, 95% confidence interval. Relative risks were also calculated. Among genetic thrombophilia, the risk of PL was highest with protein S deficiency (16%, p=0.006) followed by plasminogen activator inhibitor-1 4G/4G (23%, p=0.007) polymorphism. Among acquired markers, the risk of PL was the highest in women with anti-cardiolipin antibodies (24%, p=0.0001), followed by anti-annexin V antibodies (23%, p=0.0009) and lupus anticoagulants (8%, p=0.02). Thrombophilia, inherited and acquired, is an important contributing factor in unexplained RPL and should be screened in the order of its prevalence.

Erratum to: A novel ELISA for diagnosis of Glanzmann's thrombasthenia and the heterozygote carriers.

Erratum to: Annals of Hematology 91(6): 917­921. DOI 10.1007/s00277-011-1390-1 . The authors inadvertently omitted 2 fellow authors from the author list: Dr. Diego Butera should be listed as the fourth author. His affiliation is Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, Australia. His contributions are as follows: Designed, synthesized and produced EcAPv. He has no competing interests to declare. Dr. Geraldo S. Magalhaes should be listed as the fifth author. His affiliation is Laboratory of Immunopathology, Butantan Institute, São Paulo, SP, Brazil. His contributions are as follows: Produced more EcAPv when requested in October 2009. He has no competing interests to declare.

Nanoimaging in cardiovascular diseases: Current state of the art.

Nanotechnology has been integrated into healthcare system in terms of diagnosis as well as therapy. The massive impact of imaging nanotechnology has a deeper intervention in cardiology i.e. as contrast agents , to target vulnerable plaques with site specificity and in a theranostic approach to treat these plaques, stem cell delivery in necrotic myocardium, etc. Thus cardiovascular nanoimaging is not limited to simple diagnosis but also can help real time tracking during therapy as well as surgery. The present review provides a comprehensive description of the molecular imaging techniques for cardiovascular diseases with the help of nanotechnology and the potential clinical implications of nanotechnology for future applications.

Analysis of F8 inversions as risk factors for FVIII inhibitor development in Indian severe haemophilia A patients.

FVIII inhibitor development in haemophilia A (HA) patients, especially those with severe manifestations is a serious adverse effect in patients with haemophilia A, and the clinical management of these patients is very difficult as most don't respond to conventional treatment. Many genetic and non-genetic risk factors have been proposed however, these are diverse in different population groups, highlighting the importance of determining specific risk factors for each population. F8 mutations and especially inversions, which are the most common causative mutation in severe HA, have been significantly associated with inhibitor development earlier, however there is no conclusive data so far with regard to Indian haemophiliacs. This study provides novel evidence that intron 22 inversions in the F8 gene are indeed significantly associated with FVIII inhibitor development in Indian haemophiliacs. Further studies with other risk factors would enable better insights into the immune response towards FVIII in these patients, and possibly help to characterize patients at a higher risk for inhibitor development.