Flow cytometry - clinical cases

Flow cytometry - clinical cases

Pathology (2014) 46(S1), pp. S37–S41 Immunopathology FLOW CYTOMETRY – CLINICAL CASES 1,2,3 William A. Sewell 1SydPath, St Vincent’s Hospital Sydney...

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Pathology (2014) 46(S1), pp. S37–S41

Immunopathology

FLOW CYTOMETRY – CLINICAL CASES 1,2,3

William A. Sewell 1SydPath, St Vincent’s Hospital Sydney, 2St Vincent’s Clinical School, University of NSW, and 3Garvan Institute of Medical Research, Sydney, NSW, Australia This is an educational presentation, and the target audience of the session will be trainees. Clinical cases will be used to illustrate practical applications of flow cytometry, and the talk will build on the overview of flow cytometry presented by the previous speaker. The presentation will provide case-based examples of various methodological aspects of flow cytometry, such as gating strategy, compensation, panel design, use of controls, troubleshooting, etc. Particular emphasis will be placed on the analysis of lymphocyte subsets, a key function of the immunopathology laboratory, and the presentation will outline an approach to interpretation of common abnormalities. Principles of the approach to identification and characterisation of monoclonal populations will also be presented.

PERSONALISED MEDICINE IN AUTOIMMUNE DISEASES: MYTH OR REALITY? Marvin Fritzler University of Calgary, Alberta, Canada

NEW AUTOANTIBODIES IN CHILDHOOD ENCEPHALITIS

Progress in understanding the power of genomics, proteomics, metabolomics and other ‘omics’ has sharpened perspectives of clinical medicine, particularly in appreciating that in the realm of therapeutics, ‘one size does not fit all’. This is leading to the rapid emergence of personalised medicine (PM) and related approaches such as pharmacogenomics. PM is not an entirely new concept because it has been practiced in many disciplines, most notably oncology, for well over a decade. However, with the availability of newer multiplexed and related high throughput array technologies, health care providers and payers, along with the therapeutic and diagnostic industries are increasingly focused on the potential advantages of PM. The use of PM in rheumatoid arthritis and related systemic autoimmune rheumatic diseases is emerging as an important consideration. This session will highlight the background information leading to the rapid emergence of PM, the compelling cases for PM, the technologies at our disposal, the essential growing role of diagnostic immunology in a successful PM enterprise and the caveats the may hinder wide adoption of PM in the foreseeable future.

NOVEL ASSAYS BASED ON IMMUNE RESPONSES TO SYNTHETIC SM PEPTIDES IN THE DIAGNOSIS OF SYSTEMIC LUPUS ERYTHEMATOSUS Renfen Chen1, Andrew Williams1,2, Louise Weinholt1,2 and , Associate Professor Stephen Adelstein1,2 1Department of Clinical Immunology, Royal Prince Alfred Hospital, and 2Sydney Medical School, the University of Sydney, Sydney, NSW, Australia Print ISSN 0031-3025/Online ISSN 1465-3931

Background: Antibodies to Sm proteins are highly specific but insensitive in diagnosis of systemic lupus erythematosus (SLE). Citrullination of autoantigens increases immunogenicity in several autoimmune conditions, but has not been investigated in SLE. Methods: Immune reactivity to native and citrullinated Sm peptides was compared in a novel ELISA and an ex vivo whole bloodstimulation assay in patients with SLE and controls. Results: Increased antibody binding and enhanced cytokine responses to citrullinated Sm peptides were observed in blood from some patients with SLE. The novel anti-Sm combined peptide ELISA (SCP assay) developed has a good clinical sensitivity (80.6%) and specificity (92.7%) for diagnosis of SLE. A whole blood-Sm peptide cocktail stimulation assay using IL-1b as a response marker shows a sensitivity of 76.5% and specificity of 93.1% for distinguishing patients with SLE from controls. Conclusions: The newly established anti-SCP ELISA and ex vivo whole blood-Sm peptide cytokine stimulation assay, are significantly better than other currently used assays for the diagnosis of SLE. The reactivity of lymphocytes of patients with SLE to citrullinated Sm peptides shows specificity and allows probing of the repertoire of B and T cell responses to Sm related antigens, which raises the prospect that citrullination of self-antigens may play an important role in the pathogenesis of SLE.

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Russell C. Dale Neuroimmunology Group, Institute for Neuroscience and Muscle Research, the Children’s Hospital at Westmead, and University of Sydney, Sydney, NSW, Australia Autoimmune and inflammatory brain disease constitute a significant proportion of acute neurological presentations in children, and untreated these disorders can result in neurological disability. New autoantibodies are improving the awareness of these treatable autoimmune CNS disorders. A recent paradigm in the autoantibody field is that autoantibodies that are ‘disease-causing’ or ‘disease-contributing’ bind to the extracellular domain of receptors, channels or proteins essential for neurotransmission or cell function. Therefore, assays that measure these autoantibodies typically use cell based assays that express the antigen of interest in its conformational state. These paradigms have resulted in the discovery of autoantibodies that are associated with a significant proportion of patients with encephalitis and other autoimmune encephalopathy. Autoantibodies and their disease associations include anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in CNS demyelination, anti-NMDA receptor antibodies in NMDAR encephalitis, antibodies against the voltage gated potassium channel complex in autoimmune limbic encephalitis and autoimmune epilepsy, and antibodies that bind to dopamine-2 receptor in basal ganglia encephalitis. These disorders are generally reversible with immune suppression, and the outcome appears better with early treatment. Second line immune suppression such as rituximab is increasingly being used in this context, and the risk versus benefit of these therapies is being assessed

2014 Royal College of Pathologists of Australasia

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