Elizabeth Mayne

Increased tissue factor expression on circulating monocytes in chronic HIV infection: relationship to in vivo coagulation and immune activation.

HIV infection is associated with an increased risk of thrombosis; and as antiretroviral therapy has increased the lifespan of HIV-infected patients, their risk for cardiovascular events is expected to increase. A large clinical study found recently that all-cause mortality for HIV(+) patients was related to plasma levels of interleukin-6 and to D-dimer products of fibrinolysis. We provide evidence that this elevated risk for coagulation may be related to increased proportions of monocytes expressing cell surface tissue factor (TF, thromboplastin) in persons with HIV infection. Monocyte TF expression could be induced in vitro by lipopolysaccharide and flagellin, but not by interleukin-6. Monocyte expression of TF was correlated with HIV levels in plasma, with indices of immune activation, and with plasma levels of soluble CD14, a marker of in vivo lipopolysaccharide exposure. TF levels also correlated with plasma levels of D-dimers, reflective of in vivo clot formation and fibrinolysis. Thus, drivers of immune activation in HIV disease, such as HIV replication, and potentially, microbial translocation, may activate clotting cascades and contribute to thrombus formation and cardiovascular morbidities in HIV infection.

Increased platelet and microparticle activation in HIV infection: Upregulation of P-selectin and tissue factor expression

Objective:HIV-1–infected patients have an increased risk for atherothrombosis and cardiovascular disease, but the mechanism behind these risks is poorly understood. We have previously reported that expression of tissue factor (TF) on circulating monocytes is increased in persons with HIV infection and that TF expression is related to immune activation, to levels of HIV in plasma, and to indices of microbial translocation. In this study, we explore the activation state of platelets in HIV disease. Methods:Here, using flow cytometry-based assays, we measured platelet and platelet microparticle (PMP) activation in samples from HIV-1–infected donors and controls. Results:Platelets and PMPs from HIV-1–infected patients are activated (as reflected by expression of CD62 P-selectin) and also more frequently expressed the procoagulant TF than did platelets and PMPs obtained from controls. Expression of these proteins was directly related to expression of TF on monocytes, to markers of T-cell activation (CD38 and HLA-DR), and to plasma levels of soluble CD14, the coreceptor for bacterial lipopolysaccharride. Platelet and microparticle expression of TF was not related to plasma levels of HIV but expression of P-selectin was related to plasma levels of HIV; neither TF nor P-selectin expression was related to CD4 T-cell count. Conclusions:Platelets and microparticles are activated in HIV infection, and this activated phenotype may contribute to the increased risk for cardiovascular and thrombotic events in this population although a role for other confounding cardiovascular risks cannot be completely excluded.

A High Burden Human Immunodeficiency Virus and Tuberculosis Resource Limited Setting, Gains from Including Xpert MTB/RIF in the Diagnostic Algorithm of Fluid Specimens Submitted for Exclusion of Lymphoma by Immunophenotypic Analysis

This study investigated the benefit of incorporating Xpert MTB/RIF into the diagnostic algorithm of fluid specimens received for immunophenotypic analysis to exclude lymphoma. It was found that in a high burden HIV/TB setting, like South Africa, 130/229 (57%) of fluid specimens referred for immunophenotypic analysis to exclude lymphoma are not referred for concurrent MTBC liquid culture testing by the treating clinician. Of 99/229 (43%) specimens with corresponding culture results, Xpert sensitivity and specificity were 50% (CI:26–75%) and 99% (CI:91–100%) respectively. This demonstrates that incorporation of Xpert into the laboratory diagnostic algorithm in the immunophenotypic laboratory would improve patient work-up and care.

Combination of acquired von Willebrand syndrome (AVWS) and Glanzmann thrombasthenia in monoclonal gammopathy of uncertain significance (MGUS), a case report

BackgroundAutoimmune paraphenomena, are associated with B-cell lymphoproliferative disorders, including monoclonal gammopathy of uncertain significance. These paraphenomena can rarely include acquired bleeding disorders.Case presentationThis case study reports an unusual clinical presentation of 2 acquired bleeding disorders, Acquired von Willebrand syndrome (disease) and Acquired Glanzmann’s thrombasthenia, in an elderly patient with monoclonal gammopathy of uncertain significance.ConclusionsAcquired bleeding disorders are often underdiagnosed and a high degree of clinical suspicion is required. The patient in this study demonstrated platelet aggregometry which was atypical for isolated Glanzmann’s thrombosthenia because of the severe concomitant endogenous decrease in von Willebrand factor. There was an absence of platelet aggregation to all tested agonists including ristocetin. Once the diagnosis was made, however, the patient showed a partial response to intravenous immunoglobulin confirming the immunological pathogenesis in this case. This case highlights the need to consider acquired bleeding disorders in patients with a possible predisposing factor.

Pathogenic factors associated with development of disseminated intravascular coagulopathy (DIC) in a tertiary academic hospital in South Africa

Introduction Disseminated intravascular coagulopathy (DIC) is a thrombotic microangiopathy arising from consumption of both coagulation factors and platelets. DIC is triggered by a number of clinical conditions including severe infection, trauma and obstetric complications. Early diagnosis and treatment of the underlying condition is paramount. A high clinical index of suspicion is needed to ensure that patients at risk of developing DIC are appropriately investigated. Methods In order to establish the clinical conditions most frequently associated with DIC, we reviewed all DIC screens received at a tertiary hospital in Johannesburg, South Africa over a 1 year period. Results The commonest clinical condition associated with DIC in our population was infection with 84% of patients infected with an identified pathogen. The most frequently diagnosed pathogen was HIV followed by Mycobacterium tuberculosis and other bacterial infections. In the majority of cases, bacteria were isolated from blood cultures. In 47 patients, HIV was the only pathogen which could be isolated. A relative risk ratio of 2.73 and an odds ratio of 29.97 was attributed to HIV for development of a DIC. A malignancy was present in 51 of the patients of which approximately 60% had co-existing infection. No cause could be attributed in 30 patients. Conclusion Infection was identified in the majority of the patients diagnosed with DIC in this study. HIV showed the highest relative risk ratio of all pathogens although previous studies have not suggested that HIV was strongly associated with DIC. In almost half of the HIV infected patients, there was no other pathogen isolated despite extensive investigation. This suggests that HIV has a strong association with the development of DIC, warranting further research into the relationship between HIV and disseminated microvascular thrombosis.

Validation of the Mission® PTCoagulation Monitoring point-of-care device for the outpatient management of patients on long-term warfarin therapy

Sir, Warfarin remains the mainstay longterm anticoagulation for indications such as venous thromboembolic disease (VTED) and atrial fibrillation despite introduction of direct oral anticoagulants (DOACS) which do not require routine monitoring.1 Warfarin has a narrow therapeutic index, and activity is affected by various factors including diet, drugs, liver function and genetic polymorphisms. The anticoagulant activity of warfarin is assessed in the laboratory with a prothrombin time (PT) which guides dosing. To control for the potency of the thromboplastin reagent which initiates clot formation, the PT is converted to an international normalized ratio (INR). The target INR for most patients on warfarin therapy is 2.03.0.1 Monitoring of patients on longterm warfarin entails venous blood sample collection with analysis in a laboratory on coagulation analysers. Although important to ensure efficacy and safety, this is timeconsuming and labourintensive.2 Data suggest that monitoring of INRs with pointofcare (POC) devices is a viable option which also encourages patient ownership of treatment.3-5 POC testing (POCT) is, therefore, an attractive alternative to centralized testing, particularly in remote, resourcepoor locations and can expedite test results, improving patient care. Previously validated PT POC devices were accurate and precise, although with greater deviations from laboratory results at INR values above 4.52,6 suggesting that this method of testing is feasible. Concerns about widespread implementation of INR POCT remain since few highquality studies focusing on patient outcomes are available.3,7 The World Health Organization (WHO) published the ASSURED guidelines to guide laboratories in resourcelimited settings in selecting and implementing POCT.8,9 An international survey in the primary healthcare setting reported that INR POCT was utilized by almost half of the Australian, American and British primary care clinicians.6 We performed a validation of the Mission® PT Coagulation Monitoring POC device (supplied by Acon® Laboratories) at the National Health Laboratory Service (NHLS) coagulation unit servicing the warfarindosing clinic at the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) in Johannesburg, South Africa. The coagulometer was evaluated in 329 patients on longterm warfarin therapy attending the clinic. Ethics approval was obtained from the Human Research Ethics Committee (HREC) (Medical) of the University of the Witwatersrand (WITS) (Certificate number M170299). TABLE 1 Cliniciansupplied indications for longterm warfarin therapy in the study population

Evaluation of the diagnostic utility of individual parameters in the disseminated intravascular coagulation (DIC) panel for use in underresourced settings

References: 1. Toh C, Alhamdi Y. Current consideration and management of disseminated intravascular coagulation. Hematology. 2013;2013(1):286-291. 2. Levi M, Toh C, Thachil J, Watson H. Guidelines for the diagnosis and management of disseminated intravascular coagulation. British Journal of Haematology. 2009;145(1):24-33. 3. Taylor FB Jr, Toh CH, Hoots WK, et al. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost. 2001; 86(5):1327-1330. 4. Wada H, Asakura H, Okamoto K, Iba T, Uchiyama T, Kawasugi K et al. Expert consensus for the treatment of disseminated intravascular coagulation in Japan. Thrombosis Research. 2010;125(1):6-11. 5. Kinasewitz G, Zein J, Lee G, Nazir S, Taylor F. Prognostic value of a simple evolving disseminated intravascular coagulation score in patients with severe sepsis*. Critical Care Medicine. 2005;33(10):2214-2221. 6. Wada H, Thachil J, Di Nisio M, Mathew P, Kurosawa S, Gando S et al. Guidance for diagnosis and treatment of disseminated intravascular coagulation from harmonization of the recommendations from three guidelines. Journal of Thrombosis and Haemostasis. 2013;11(4):761-767. 7. Levi M, ten Cate H. Disseminated Intravascular Coagulation. New England Journal of Medicine. 1999;341(8):586-592. 8. Dhainaut J, Yan S, Joyce D, Pettila V, Basson B, Brandt J et al. Treatment effects of drotrecogin alfa (activated) in patients with severe sepsis with or without overt disseminated intravascular coagulation1. Journal of Thrombosis and Haemostasis. 2004;2(11):1924-1933. Society: ISTH JMHW JAAM

Clone wars: the evolution of therapeutic resistance in cancer

Cancer Catherine M. Worsley a,b , Elizabeth S. Mayne a,b , Rob B. Veale c . a Department of Molecular Medicine and Haematology, Faculty of Health Science, University of the Witwatersrand, Johannesburg. b Department of Molecular Medicine and Haematology, Charlotte Maxeke Johannesburg Academic Hospital, National Health Laboratory Service. c School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg.

The utility of thrombo-elastography in the monitoring of aspirin therapy

To assess the utility of the thrombo-elastogram in monitoring of aspirin therapy 25 healthy volunteers were selected and given low-dose aspirin therapy. Thrombo-elastography and platelet aggregometry were conducted at baseline and 1 week later. After 1 week of aspirin therapy, thrombo-elastogram data failed to demonstrate a significant change in the clotting profile. Platelet aggregometry identified significant changes in the clotting profile in response to stimulation with arachidonic acid, adrenaline and ADP. We conclude that thrombo-elastography may not have utility in monitoring of response to aspirin.