Fibrosis and bone marrow: understanding causation and pathobiology.

Bone marrow fibrosis represents an important structural change in the marrow that interferes with some of its normal functions. The aetiopathogenesis of fibrosis is not well established except in its primary form. The present review consolidates current understanding of marrow fibrosis. We searched PubMed without time restriction using key words: bone marrow and fibrosis as the main stem against the terms: growth factors, cytokines and chemokines, morphology, megakaryocytes and platelets, myeloproliferative disorders, myelodysplastic syndrome, collagen biosynthesis, mesenchymal stem cells, vitamins and minerals and hormones, and mechanism of tissue fibrosis. Tissue marrow fibrosis-related papers were short listed and analysed for the review. It emerged that bone marrow fibrosis is the outcome of complex interactions between growth factors, cytokines, chemokines and hormones together with their facilitators and inhibitors. Fibrogenesis is initiated by mobilisation of special immunophenotypic subsets of mesenchymal stem cells in the marrow that transform into fibroblasts. Fibrogenic stimuli may arise from neoplastic haemopoietic or non-hematopoietic cells, as well as immune cells involved in infections and inflammatory conditions. Autoimmunity is involved in a small subset of patients with marrow fibrosis. Megakaryocytes and platelets are either directly involved or are important intermediaries in stimulating mesenchymal stem cells. MMPs, TIMPs, TGF-ß, PDGRF, and basic FGF and CRCXL4 chemokines are involved in these processes. Genetic and epigenetic changes underlie many of these conditions.

Efficacy of emicizumab in von Willebrand disease (VWD) patients with and without alloantibodies to von Willebrand factor (VWF): Report of two cases and review of literature.

INTRODUCTION: von Willebrand disease (VWD) is the common bleeding disorder with a clinically relevant bleeding prevalence of 1:10,000. von Willebrand disease patients lack both von Willebrand factor (VWF) and factor VIII (FVIII), which are critical for normal haemostasis. The conventional treatment for VWD includes desmopressin and replacement therapy with plasma derived FVIII with VWF concentrates or recombinant VWF. Development of alloantibodies is a rare occurrence, there is a paucity in the literature of treatment modalities in these patients. Not many reports are available in literature on the efficacy of emicizumab in VWD patients with or without alloantibodies to VWF. AIM: To do systematic review of literature on emicizumab in VWD and report our experience of emicizumab in two patients of VWD METHODS: We used electronic search engines till May 2021 in 'Google scholar' and 'PubMed', to collect the case reports or case series on use of emicizumab for management of VWD. Two of our severe VWD patients were successfully treated with emicizumab. A systematic review was performed and the results discussed. RESULTS: The electronic search revealed six case reports using emicizumab for treatment of VWD. Two were in vitro studies and four in patients with VWD type 3 disease. In vitro studies and in VWD patients on emicizumab, showed improvement in thrombin generation and fibrin formation. Among four patients, three had alloantibodies to VWD and one was negative. All these patients were treated with emicizumab for 6-12 m. After starting emicizumab, none of them had spontaneous bleeding requiring treatment. During treatment with emicizumab, one patient had trauma-associated soft tissue hematoma, which was treated with rFVIIa and another patient had bleeding following dental exfoliation treated with Humate P. We treated two of our VWD patients one with and one without inhibitors with emicizumab after failure of other therapies. Both the patients showed marked improvement and continued to remain well and free of bleeding episodes. None of the patients had any thrombosis or thrombotic microangiopathy (TMA) during treatment with emicizumab. CONCLUSION: In conclusion, this review supports the safety and efficacy of emicizumab in type 3 VWD patients with or without alloantibodies. Further large studies are required to confirm the safety and efficacy of emicizumab in VWD.

Rare Occurrence of Inhibitors in Von Willebrand Disease: A Case Report.

Introduction: Type 3 Von Willebrand Disease (VWD) is the least common but the most severe form of a disease, with a prevalence of about 0. 5 to 1 per million in Western countries. The prevalence of type 3 VWD in the developing countries, with a high degree of consanguinity, is about 6 per million. Moreover, due to underdiagnosis of the milder cases, the prevalence of type 3 VWD is about 50% of the cases. Rarely, some patients develop the Von Willebrand Factor (VWF) inhibitors, which may subsequently develop severe anaphylactic reactions on further exposure to the VWF containing factor replacement therapy. The prevalence of inhibitor development in patients with type 3 VWD has been shown to be in the range of 5.8 to 9.5%. In the absence of a gold standard assay for the quantitation of VWF inhibitors, a correct diagnosis and management of these patients are often challenging. Objectives: The objective of this study is to standardize the Bethesda assay for the VWF inhibitors and to estimate the VWD inhibitor titer in two cases of congenital type 3 VWD, which developed the VWF inhibitors. Results and Conclusions: We could successfully standardize the Bethesda assay for the quantitation of VWF inhibitors in two patients with congenital type 3 VWD with inhibitors.

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.

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.

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.

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.

The Epidemiology of FVIII Inhibitors in Indian Haemophilia A Patients.

A serious complication of replacement therapy in patients with bleeding disorders is the development of 'inhibitors', particularly FVIII inhibitors in haemophilia A patients. This leads to an increase in the management cost, morbidity and mortality, especially post-operatively. The mechanism of FVIII inhibitor development is quite complex and it is difficult to predict inhibitor development, but a prompt and accurate diagnosis is critical as early therapy can save lives. The aim of this study was to screen patients with bleeding disorders in India for inhibitors, and to analyse and compare the prevalence of inhibitors in different regions in India. Patient details were recorded and blood samples were collected in sodium citrate vacutainers from 1,505 patients with bleeding disorders, in different cities in India. Coagulation and inhibitor screening assays were performed, followed by the Bethesda assay in inhibitor positive samples to quantify the FVIII inhibitor titre. Out of the 1,505 samples analysed, 1,285 were Haemophilia A patients, out of which 78 (6.07 %) were positive for 'FVIII Inhibitors'. The highest incidence of FVIII Inhibitors was seen in South India (13.04 %). The highest incidence of 20.99 % was observed in Chennai, followed by Hyderabad (13.33 %), Jammu (9.90 %) and Guwahati (8.51 %), respectively, with respect to the samples analysed. The other regions showed an inhibitor incidence <8 %. The incidence of inhibitors in haemophilia A patients is different in different regions of India; this may be due to the intensity of treatment, type of product or the genetic characteristics of these patients.

Molecular pathology of rare bleeding disorders (RBDs) in India: a systematic review.

BACKGROUND: Though rare in occurrence, patients with rare bleeding disorders (RBDs) are highly heterogeneous and may manifest with severe bleeding diathesis. Due to the high rate of consanguinity in many caste groups, these autosomal recessive bleeding disorders which are of rare occurrence in populations across the world, may not be as rare in India. OBJECTIVES: To comprehensively analyze the frequency and nature of mutations in Indian patients with RBDs. METHODS: Pubmed search was used (www.pubmed.com) to explore the published literature from India on RBDs using the key words "rare bleeding disorders", "mutations", "India", "fibrinogen", "afibrinogenemia", "factor II deficiency", "prothrombin" "factor VII deficiency", "factor V deficiency", "factor X deficiency", "factor XI deficiency", "combined factor V and VIII deficiency", "factor XIII deficiency", "Bernard Soulier syndrome" and "Glanzmanns thrombasthenia" in different combinations. A total of 60 relevant articles could be retrieved. The distribution of mutations from India was compared with that of the world literature by referring to the Human Gene Mutation Database (HGMD) (www.hgmd.org). RESULTS: Taken together, 181 mutations in 270 patients with different RBDs have been reported from India. Though the types of mutations reported from India and their percentage distribution with respect to the world data are largely similar, yet much higher percentage of small deletions, duplication mutations, insertions, indels were observed in this analysis. Besides the identification of novel mutations and polymorphisms, several common mutations have also been reported, which will allow to develop a strategy for mutation screening in Indian patients with RBDs. CONCLUSION: There is a need for a consortium of Institutions working on the molecular pathology of RBDs in India. This will facilitate a quicker and cheaper diagnosis of RBDs besides its utility in first trimester prenatal diagnosis of the affected families.

Influence of CYP2C9 and VKORC1 gene polymorphisms on warfarin dosage, over anticoagulation and other adverse outcomes in Indian population.

The aim of this study was to determine the frequencies of SNPs in the vitamin K epoxide reductase complex subunit 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9) genes and their effect on warfarin dose requirement, over anticoagulation and other adverse outcomes in Indian population. A total of 145 warfarin treated patients for various clinical conditions were screened for VKORC1 and CYP2C9 gene polymorphisms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. We found that homozygous VKORC1-1639 AA and CYP2C9 (*)3/(*)3 polymorphisms showed 100% association with risk of over anticoagulation and other adverse events. Carriers of two heterozygous variant genotypes also showed significant association with risk of over anticoagulation and bleeding. Single variant carrier patients were found to require low warfarin dose as compared to wild type (CYP2C9(*)1/(*)1 and VKORC1- 1639 GG) patients. The major impact of VKORC1 and CYP2C9 genotypes was observed in the first month of anticoagulation. A drastic variation from other Asian countries was observed in Indian population with regard to the distribution of different VKORC1 -1639 genotypes. Our results suggest that both VKORC1 and CYP2C9 genotypes showed significant impact on warfarin dose requirement, over anticoagulation in the first month of anticoagulation and number of bleeding episodes. The variation in therapeutic dosage of warfarin and the associated adverse events across different populations is due to the wide differences in the frequency of these warfarin sensitive alleles.