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Food allergy in adults
PATHOLOGY UPDATE 2009 ABSTRACT PUBLICATION 39
Immunopathology THE CLINICAL UTILITY OF MOLECULAR DIAGNOSTIC TESTING FOR PRIMARY IMMUNE DEFICIENCY DISORDERS Rohan Ameratunga1, See-Tarn Woon2 1 Adult and Paediatric Immunologist, Auckland 2 LabPlus, Auckland City Hospital, Auckland, New Zealand Over the last 20 years, there has been rapid progress in the identification of the genetic basis of a large number of primary immune deficiency disorders (PIDs). Contributing factors are major breakthroughs in genetics including the ability to generate genetically altered mice. Likewise the advances in bioinformatics and large scale sequencing technology have made gene identification feasible. This talk explores the clinical utility of gene testing for primary immune deficiency diagnosis. Advantages include certainty of diagnosis, prognostic information, family studies, prenatal diagnosis and the possibility of pre-implantation diagnosis. Genetic testing should now be regarded as an essential part of PID management. In 2003, The Immune Deficiency Foundation of New Zealand (IDFNZ) funded a feasibility study to establish a routine PID genetic testing service at Auckland City Hospital. Senior management at Auckland City Hospital made a far-sighted decision to fund the service and a senior scientist (S-TW) was appointed in 2005. The service offers a customised gene testing programme. New tests are available in 23 weeks and results from established tests are available within a week. Other assays such as T cell receptor excision circle (TREC) analysis are also available. The service has been accredited by IANZ, the laboratory testing programme in New Zealand. This talk illustrates the value of molecular immunology diagnosis with a series of case studies referred to the Auckland City Hospital.
VIROLOGY OF HIV Anthony L Cunningham Centre for Virus Research, Westmead Millennium Institute and University of Sydney, Sydney, NSW, Australia HIV appears to have spread to humans from chimpanzees in the early 20th century in Central Africa. Compared with other viruses, it has a relatively low transmission rate sexually or parentally. Nevertheless, it continues to spread and devastate populations in Africa, Asia and the Pacific, Eastern Europe and South America. Studies of the replication cycle of the virus have allowed the development of anti-viral agents targetted at virus binding, entry, integration and host DNA and assembly and proleolytic cleavage, as well as mechanisms of resistance allowing synthesis of second generation anti-virals targeted at resistant mutants. Elucidation of the human genome and subsequent genomic and proteomic studies are enabling a greater understanding of the interactions between the virus and host cell metabolism, including that used by the virus for refashioning cellular processes for its own benefit and evading both intra and extra-cellular, innate and adaptive immunities. The failure of recent first generation vaginal microbicide and second generation vaccine clinical trials have refocussed biomedical research efforts on understanding the mechanism of genital tract
infection and often the mechanisms involved in disease progression and anti-viral immunity. Comparisons between new world and old world monkeys infected with monkey HIV (SIV) who do or do not progress to AIDS, respectively, have confirmed earlier suggestions that activation of T lymphocytes and other immune cells, especially in tissue, appears to contribute to immunosuppression and CD4 lymphocyte depletion. The roles of newly discovered T cell subtypes such as TH17 cells and T regulatory cells are currently being evaluated. New prognostic tests are being introduced for evaluation of viral resistance, viral load and CD4 lymphocyte counts in the resource poor setting and for R5/X4 phenotyping of HIV for antiviral agents directed at interrupting HIV binding to CCR5.
THE AUSTRALIAN AND INTERNATIONAL RESPONSE TO HIV/AIDS ASPECTS OF COMPARISON AND CONTRAST
Roger Garsia Department of Clinical Immunology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia Australia’s response to HIV/AIDS has contained the local epidemic. Centres of HIV epidemiology, clinical, social and virology research have contributed greatly to the understanding of clinical, pathophysiological, treatment and behavioural aspects of HIV/ AIDS in those living with, and at risk for, HIV. Also underpinning the success in fighting HIV/AIDS is a highly regulated, quality assured public/private pathology enterprise interacting with the biomedical industry, pharmaceutical industry innovators and international research groups. Features of the Australian response to HIV have been partnerships of stakeholders, including researchers and pathologists, which have led to a series of formal, bipartisan, National HIV/AIDS Strategy documents and implementation programs operating in a universal access to health care environment. Innovation, such as in politically difficult harm reduction models of prevention, have been adopted and the documented success of the Australian needle and syringe program (NSP), human rights based legislative frameworks and evidencedbased public health policy decision-making has demonstrated that HIV epidemics in intravenous drug use (IVDU) and heterosexual populations can be largely prevented. Recent increases in HIV transmission in gay men reflected in rising rates of new HIV diagnoses, demand innovative approaches in prevention, testing and treatment. Findings from the Australian experience have relevance to other jurisdictions embarking on national strategy development in the HIV/AIDS domain.
FOOD ALLERGY IN ADULTS Connie Katelaris University of Western Sydney, and Department of Immunology and Allergy, Campbelltown Hospital, Campbelltown, NSW, Australia There has been an increase in the prevalence of food allergy seen in children in the last few decades. As these children reach adulthood, physicians will have an increased role in ongoing management of
40
PATHOLOGY UPDATE 2009 ABSTRACT PUBLICATION
EOSINOPHLIC DISORDERS; EOSINOPHILIC OESOPHAGITIS
underlying disease associated with hypereosinophilia, consideration is given to the hypereosinophilic syndrome (HES), a heterogenous group of eosinophilic disorders associated with high-grade peripheral eosinophilia (]1500 eosinophils/mm3) usually accompanied by end organ damage/dysfunction. Advances in our understanding of the complex pathobiology of eosinophilic disorders have led to insights into the molecular basis of HES variants that make up the syndrome. These insights have led to treatment breakthroughs including molecularly targeted therapies for FIP1L1/PDGFRapositive HES. Other specific molecular associations are now also recognised. Advances in our understanding of the pathobiology of HES have also led to increasing recognition of the pivotal role that the cytokine IL-5 plays in eosinophilopoiesis, eosinophil activation and eosinophil survival. First line treatments (i.e., corticosteroids, hydroxyurea, IFN-a, imatinib) have demonstrated efficacy in the different types of HES. The emergence of new anti-IL-5 monoclonal antibodies (reslizumab, mepolizumab) with the ability to directly target IL-5 represent a promising approach to HES treatment and these new therapies mark an important step in targeted therapy to prevent eosinophil organ tissue infiltration and damage. The full potential of these agents and their respective place needs to be further assessed.
Raymond Mullins John James Medical Centre, Canberra, ACT, Australia
EIGHT COLOUR DIAGNOSTIC FLOW CYTOMETRY
these allergic disorders. Food allergy in adults may result from a persistence of reactions that commenced in infancy and early childhood or it may occur for the first time in adulthood through new sensitisations. Such sensitisation may occur directly to a food allergen or indirectly via cross reactivity with an aeroallergen. Adults may present with a spectrum of clinical manifestations from oral allergy syndrome to fatal anaphylaxis. Persistence of childhood allergy is particularly relevant for peanut allergy which has significantly increased in the last two decades. Only approximately 20% of peanut-allergic children will develop tolerance to peanuts so there will be an increasing number of individuals reaching adulthood where this problem will need to be addressed. In addition to peanut, tree nuts, fruits, vegetables and seafood are implicated as common causes of food allergy in adulthood. The management of food allergy consists of appropriate education regarding avoidance of implicated foods, modifying potential risk factors for anaphylaxis such as asthma, and prompt recognition and treatment of acute reactions.
Eosinophilic oesophagitis is a chronic inflammatory condition of the oesophagus, occurring most commonly in atopic patients of any age and manifesting with one or more symptoms of chest pain, severe acid reflux, dysphagia or food impaction but can be seen in asymptomatic patients. Complications include the need for endoscopy to remove food boluses and dilatation of the oesophagus resulting from stricture formation from tissue remodelling. Diagnosis must be based on biopsy of the upper oesophagus, since eosinophilic infiltrates are often seen in the lower oesophagus in patients with reflux disease, and macroscopic abnormities are only seen in around 75% of patients. Incidence appears to be increasing, with estimates of 0.9/10,000 Australian children and 6% of adults undergoing elective endoscopy. Pathogenesis appears related to cell-mediated responses to inhalant or swallowed food allergen in most, making IgE-mediated allergy testing less reliable. Histology is characterised by an intense eosinophilic infiltration (20 eosinophils/HPF), degranulation and micro-abscesses. Eosinophilderived mediators likely influence gastrointestinal motility and promote remodelling. Genetic susceptibility (8% have a first degree relative with the condition) may be conveyed by polymorphisms in the IL-13 receptor and eotaxin-3 genes. Management centres on dietary manipulation, medication (proton pump inhibitors and topical asthma steroids), stricture dilatation and allergen immunotherapy (in selected cases). Trials of anti-cytokine therapy have shown promise.
William A Sewell1,2, Sandy Smith1 1 SydPath, St Vincent’s Hospital Sydney, Darlinghurst 2 Garvan Institute of Medical Research, Darlinghurst, NSW, Australia Technological improvements are enabling flow cytometry to assess an increasing number of markers simultaneously. This presentation will describe the advantages and disadvantages of an eight colour diagnostic flow cytometry system. In the determination of lymphocyte subsets, the system enables each sample to be analysed in a single tube. In haematological malignancies, the eight colour system provides improved sensitivity in the assessment of small populations. For example, several B cell markers can be determined in the same tube as kappa and lambda, enabling detection of small monoclonal B cell populations, and distinction of monoclonal populations from reactive follicular hyperplasia. The eight colour system is very useful in assessing minimal residual disease. A greater number of markers can be determined when samples, such as CSF, are analysed in a single tube because of low cell numbers. There have also been improvements in work flow, and reductions in the cost of antibodies used in multiple tubes. Disadvantages include greater complexity in data analysis, more training for pathologists and laboratory staff, and custom preparation of antibody-fluorochrome conjugates. Implementation depends on a highly skilled laboratory scientist. On balance, the improvements in diagnosis have justified the use of an eight colour system.
RECENT ADVANCES IN UNDERSTANDING EOSINOPHILIA PSEUDOTHROMBOCYTOPENIA Adrian Newland Department of Haematology, Barts and the London NHS Trust, London, United Kingdom Hypereosinophilia occurs commonly in clinical practice and is usually secondary to some underlying disorder, such as parasitic disease or allergic drug reaction. Less common causes include haematological malignancies, and connective tissue or cutaneous disorders. In cases where diagnostic assessment reveals no
Nicola Bizzaro Laboratorio di Patologia Clinica, Ospedale Civile, Tolmezzo, Italy Pseudothrombocytopenia is an uncommon and often unrecognised phenomenon that results in errors in the interpretation of platelet counts with consequent inappropriate clinical decisions or useless, and sometimes dangerous, therapeutic interventions.
Immunopathology THE CLINICAL UTILITY OF MOLECULAR DIAGNOSTIC TESTING FOR PRIMARY IMMUNE DEFICIENCY DISORDERS Rohan Ameratunga1, See-Tarn Woon2 1 Adult and Paediatric Immunologist, Auckland 2 LabPlus, Auckland City Hospital, Auckland, New Zealand Over the last 20 years, there has been rapid progress in the identification of the genetic basis of a large number of primary immune deficiency disorders (PIDs). Contributing factors are major breakthroughs in genetics including the ability to generate genetically altered mice. Likewise the advances in bioinformatics and large scale sequencing technology have made gene identification feasible. This talk explores the clinical utility of gene testing for primary immune deficiency diagnosis. Advantages include certainty of diagnosis, prognostic information, family studies, prenatal diagnosis and the possibility of pre-implantation diagnosis. Genetic testing should now be regarded as an essential part of PID management. In 2003, The Immune Deficiency Foundation of New Zealand (IDFNZ) funded a feasibility study to establish a routine PID genetic testing service at Auckland City Hospital. Senior management at Auckland City Hospital made a far-sighted decision to fund the service and a senior scientist (S-TW) was appointed in 2005. The service offers a customised gene testing programme. New tests are available in 23 weeks and results from established tests are available within a week. Other assays such as T cell receptor excision circle (TREC) analysis are also available. The service has been accredited by IANZ, the laboratory testing programme in New Zealand. This talk illustrates the value of molecular immunology diagnosis with a series of case studies referred to the Auckland City Hospital.
VIROLOGY OF HIV Anthony L Cunningham Centre for Virus Research, Westmead Millennium Institute and University of Sydney, Sydney, NSW, Australia HIV appears to have spread to humans from chimpanzees in the early 20th century in Central Africa. Compared with other viruses, it has a relatively low transmission rate sexually or parentally. Nevertheless, it continues to spread and devastate populations in Africa, Asia and the Pacific, Eastern Europe and South America. Studies of the replication cycle of the virus have allowed the development of anti-viral agents targetted at virus binding, entry, integration and host DNA and assembly and proleolytic cleavage, as well as mechanisms of resistance allowing synthesis of second generation anti-virals targeted at resistant mutants. Elucidation of the human genome and subsequent genomic and proteomic studies are enabling a greater understanding of the interactions between the virus and host cell metabolism, including that used by the virus for refashioning cellular processes for its own benefit and evading both intra and extra-cellular, innate and adaptive immunities. The failure of recent first generation vaginal microbicide and second generation vaccine clinical trials have refocussed biomedical research efforts on understanding the mechanism of genital tract
infection and often the mechanisms involved in disease progression and anti-viral immunity. Comparisons between new world and old world monkeys infected with monkey HIV (SIV) who do or do not progress to AIDS, respectively, have confirmed earlier suggestions that activation of T lymphocytes and other immune cells, especially in tissue, appears to contribute to immunosuppression and CD4 lymphocyte depletion. The roles of newly discovered T cell subtypes such as TH17 cells and T regulatory cells are currently being evaluated. New prognostic tests are being introduced for evaluation of viral resistance, viral load and CD4 lymphocyte counts in the resource poor setting and for R5/X4 phenotyping of HIV for antiviral agents directed at interrupting HIV binding to CCR5.
THE AUSTRALIAN AND INTERNATIONAL RESPONSE TO HIV/AIDS ASPECTS OF COMPARISON AND CONTRAST
Roger Garsia Department of Clinical Immunology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia Australia’s response to HIV/AIDS has contained the local epidemic. Centres of HIV epidemiology, clinical, social and virology research have contributed greatly to the understanding of clinical, pathophysiological, treatment and behavioural aspects of HIV/ AIDS in those living with, and at risk for, HIV. Also underpinning the success in fighting HIV/AIDS is a highly regulated, quality assured public/private pathology enterprise interacting with the biomedical industry, pharmaceutical industry innovators and international research groups. Features of the Australian response to HIV have been partnerships of stakeholders, including researchers and pathologists, which have led to a series of formal, bipartisan, National HIV/AIDS Strategy documents and implementation programs operating in a universal access to health care environment. Innovation, such as in politically difficult harm reduction models of prevention, have been adopted and the documented success of the Australian needle and syringe program (NSP), human rights based legislative frameworks and evidencedbased public health policy decision-making has demonstrated that HIV epidemics in intravenous drug use (IVDU) and heterosexual populations can be largely prevented. Recent increases in HIV transmission in gay men reflected in rising rates of new HIV diagnoses, demand innovative approaches in prevention, testing and treatment. Findings from the Australian experience have relevance to other jurisdictions embarking on national strategy development in the HIV/AIDS domain.
FOOD ALLERGY IN ADULTS Connie Katelaris University of Western Sydney, and Department of Immunology and Allergy, Campbelltown Hospital, Campbelltown, NSW, Australia There has been an increase in the prevalence of food allergy seen in children in the last few decades. As these children reach adulthood, physicians will have an increased role in ongoing management of
40
PATHOLOGY UPDATE 2009 ABSTRACT PUBLICATION
EOSINOPHLIC DISORDERS; EOSINOPHILIC OESOPHAGITIS
underlying disease associated with hypereosinophilia, consideration is given to the hypereosinophilic syndrome (HES), a heterogenous group of eosinophilic disorders associated with high-grade peripheral eosinophilia (]1500 eosinophils/mm3) usually accompanied by end organ damage/dysfunction. Advances in our understanding of the complex pathobiology of eosinophilic disorders have led to insights into the molecular basis of HES variants that make up the syndrome. These insights have led to treatment breakthroughs including molecularly targeted therapies for FIP1L1/PDGFRapositive HES. Other specific molecular associations are now also recognised. Advances in our understanding of the pathobiology of HES have also led to increasing recognition of the pivotal role that the cytokine IL-5 plays in eosinophilopoiesis, eosinophil activation and eosinophil survival. First line treatments (i.e., corticosteroids, hydroxyurea, IFN-a, imatinib) have demonstrated efficacy in the different types of HES. The emergence of new anti-IL-5 monoclonal antibodies (reslizumab, mepolizumab) with the ability to directly target IL-5 represent a promising approach to HES treatment and these new therapies mark an important step in targeted therapy to prevent eosinophil organ tissue infiltration and damage. The full potential of these agents and their respective place needs to be further assessed.
Raymond Mullins John James Medical Centre, Canberra, ACT, Australia
EIGHT COLOUR DIAGNOSTIC FLOW CYTOMETRY
these allergic disorders. Food allergy in adults may result from a persistence of reactions that commenced in infancy and early childhood or it may occur for the first time in adulthood through new sensitisations. Such sensitisation may occur directly to a food allergen or indirectly via cross reactivity with an aeroallergen. Adults may present with a spectrum of clinical manifestations from oral allergy syndrome to fatal anaphylaxis. Persistence of childhood allergy is particularly relevant for peanut allergy which has significantly increased in the last two decades. Only approximately 20% of peanut-allergic children will develop tolerance to peanuts so there will be an increasing number of individuals reaching adulthood where this problem will need to be addressed. In addition to peanut, tree nuts, fruits, vegetables and seafood are implicated as common causes of food allergy in adulthood. The management of food allergy consists of appropriate education regarding avoidance of implicated foods, modifying potential risk factors for anaphylaxis such as asthma, and prompt recognition and treatment of acute reactions.
Eosinophilic oesophagitis is a chronic inflammatory condition of the oesophagus, occurring most commonly in atopic patients of any age and manifesting with one or more symptoms of chest pain, severe acid reflux, dysphagia or food impaction but can be seen in asymptomatic patients. Complications include the need for endoscopy to remove food boluses and dilatation of the oesophagus resulting from stricture formation from tissue remodelling. Diagnosis must be based on biopsy of the upper oesophagus, since eosinophilic infiltrates are often seen in the lower oesophagus in patients with reflux disease, and macroscopic abnormities are only seen in around 75% of patients. Incidence appears to be increasing, with estimates of 0.9/10,000 Australian children and 6% of adults undergoing elective endoscopy. Pathogenesis appears related to cell-mediated responses to inhalant or swallowed food allergen in most, making IgE-mediated allergy testing less reliable. Histology is characterised by an intense eosinophilic infiltration (20 eosinophils/HPF), degranulation and micro-abscesses. Eosinophilderived mediators likely influence gastrointestinal motility and promote remodelling. Genetic susceptibility (8% have a first degree relative with the condition) may be conveyed by polymorphisms in the IL-13 receptor and eotaxin-3 genes. Management centres on dietary manipulation, medication (proton pump inhibitors and topical asthma steroids), stricture dilatation and allergen immunotherapy (in selected cases). Trials of anti-cytokine therapy have shown promise.
William A Sewell1,2, Sandy Smith1 1 SydPath, St Vincent’s Hospital Sydney, Darlinghurst 2 Garvan Institute of Medical Research, Darlinghurst, NSW, Australia Technological improvements are enabling flow cytometry to assess an increasing number of markers simultaneously. This presentation will describe the advantages and disadvantages of an eight colour diagnostic flow cytometry system. In the determination of lymphocyte subsets, the system enables each sample to be analysed in a single tube. In haematological malignancies, the eight colour system provides improved sensitivity in the assessment of small populations. For example, several B cell markers can be determined in the same tube as kappa and lambda, enabling detection of small monoclonal B cell populations, and distinction of monoclonal populations from reactive follicular hyperplasia. The eight colour system is very useful in assessing minimal residual disease. A greater number of markers can be determined when samples, such as CSF, are analysed in a single tube because of low cell numbers. There have also been improvements in work flow, and reductions in the cost of antibodies used in multiple tubes. Disadvantages include greater complexity in data analysis, more training for pathologists and laboratory staff, and custom preparation of antibody-fluorochrome conjugates. Implementation depends on a highly skilled laboratory scientist. On balance, the improvements in diagnosis have justified the use of an eight colour system.
RECENT ADVANCES IN UNDERSTANDING EOSINOPHILIA PSEUDOTHROMBOCYTOPENIA Adrian Newland Department of Haematology, Barts and the London NHS Trust, London, United Kingdom Hypereosinophilia occurs commonly in clinical practice and is usually secondary to some underlying disorder, such as parasitic disease or allergic drug reaction. Less common causes include haematological malignancies, and connective tissue or cutaneous disorders. In cases where diagnostic assessment reveals no
Nicola Bizzaro Laboratorio di Patologia Clinica, Ospedale Civile, Tolmezzo, Italy Pseudothrombocytopenia is an uncommon and often unrecognised phenomenon that results in errors in the interpretation of platelet counts with consequent inappropriate clinical decisions or useless, and sometimes dangerous, therapeutic interventions.