Improved prospects for food allergy prevention

ABSTRACT Three recent publications from Professor Gideon Lack have fundamentally changed our understanding of how to prevent food allergy. His team has shown that early introduction of allergenic foods may prevent food allergy in most but not all high-risk children. Various allergy and paediatric societies around the world are changing their recommendations based on these three studies. It appears there is a window of opportunity to safely introduce allergenic foods to high-risk children. This has resource implications, as some of these children will need testing and food challenges.

Comprehensive genetic testing for primary immunodeficiency disorders in a tertiary hospital: 10-year experience in Auckland, New Zealand

Background and purpose

New Zealand is a developed geographically isolated country in the South Pacific with a population of 4.4 million. Genetic diagnosis is the standard of care for most patients with primary immunodeficiency disorders (PIDs).

Methods

Since 2005, we have offered a comprehensive genetic testing service for PIDs and other immune-related disorders with a published sequence. Here we present results for this program, over the first decade, between 2005 and 2014.

Results

We undertook testing in 228 index cases and 32 carriers during this time. The three most common test requests were for X-linked lymphoproliferative (XLP), tumour necrosis factor receptor associated periodic syndrome (TRAPS) and haemophagocytic lymphohistiocytosis (HLH). Of the 32 suspected XLP cases, positive diagnoses were established in only 2 patients. In contrast, genetic defects in 8 of 11 patients with suspected X-linked agammaglobulinemia (XLA) were confirmed. Most XLA patients were initially identified from absence of B cells. Overall, positive diagnoses were made in about 23% of all tests requested. The diagnostic rate was lowest for several conditions with locus heterogeneity.

Conclusions

Thorough clinical characterisation of patients can assist in prioritising which genes should be tested. The clinician-driven customised comprehensive genetic service has worked effectively for New Zealand. Next generation sequencing will play an increasing role in disorders with locus heterogeneity.

Hereditary Angioedema as a Metabolic Liver Disorder: Novel Therapeutic Options and Prospects for Cure

Hereditary angioedema (HAE) is a rare autosomal dominant disorder caused by mutations of the SERPING1 or the Factor 12 genes. It is potentially fatal, particularly if not identified at an early stage. Apart from androgens, which are contraindicated in children and in pregnant women, a range of effective, albeit very expensive treatments have recently become available for HAE patients. The cost of these new treatments is beyond the reach of most developing countries. At this time, there is no cure for the disorder. In spite of mutations of the SERPING1 gene, autoimmunity and infections are not prominent features of the condition. Here, we present the argument that HAE should be viewed primarily as a metabolic liver disorder. This conceptual paradigm shift will stimulate basic research and may facilitate new therapeutic approaches to HAE outlined in this paper. We suggest several novel potential treatment options for HAE from the perspectives of clinical immunology, molecular biology, and liver transplantation. Many of these offer the prospect of curing the disorder. The effectiveness of these options is rapidly improving in many cases, and their risks are decreasing. Given the very high costs of treating HAE, some of these curative options may become feasible in the next decade.

The case for a national service for primary immune deficiency disorders in New Zealand

Primary immune deficiency disorders (PIDs) are rare conditions for which effective treatment is available. It is critical these patients are identified at an early stage to prevent unnecessary morbidity and mortality. Treatment of these disorders is expensive and expert evaluation and ongoing management by a clinical immunologist is essential. Until recently there has been a major shortage of clinical immunologists in New Zealand. While the numbers of trained immunologists have increased in recent years, most are located in Auckland. The majority of symptomatic PID patients require life-long immunoglobulin replacement. Currently there is a shortage of subcutaneous and intravenous immunoglobulin (SCIG/IVIG) in New Zealand. A recent audit by the New Zealand Blood Service (NZBS) showed that compliance with indications for SCIG/IVIG treatment was poor in District Health Boards (DHBs) without an immunology service. The NZBS audit has shown that approximately 20% of annual prescriptions for SCIG/IVIG, costing $6M, do not comply with UK or Australian guidelines. Inappropriate use may have contributed to the present shortage of SCIG/IVIG necessitating importation of the product. This is likely to have resulted in a major unnecessary financial burden to each DHB. Here we present the case for a national service responsible for the tertiary care of PID patients and oversight for immunoglobulin use for primary and non-haematological secondary immunodeficiencies. We propose that other PIDs, including hereditary angioedema, are integrated into a national PID service. Ancillary services, including the customised genetic testing service, and research are also an essential component of an integrated national PID service and are described in this review. As we show here, a hub-and-spoke model for a national service for PIDs would result in major cost savings, as well as improved patient care. It would also allow seamless transition from paediatric to adult services.

Application of diagnostic and treatment criteria for common variable immunodeficiency disorder

Common variable immunodeficiency disorder (CVID) is the most frequent symptomatic primary immune deficiency disorder in adults. It probably comprises a spectrum of polygenic disorders, with hypogammaglobulinemia being the overarching feature. While the majority of patients with CVID can be identified with relative ease, a significant proportion can present with minimal symptoms in spite of profound laboratory abnormalities. Here we discuss three patients who were presented to the Auckland Hospital immunoglobulin treatment committee to determine if they qualified for immunoglobulin replacement. Two were asymptomatic with profound laboratory abnormalities while the third patient was severely ill with extensive bronchiectasis. The third patient had less severe laboratory abnormalities compared with the two asymptomatic patients. We have applied four sets of published diagnostic and treatment criteria to these patients to compare their clinical utility. We have chosen these patients from the broad phenotypic spectrum of CVID, as this often illustrates differences in diagnostic and treatment criteria.

New diagnostic criteria for CVID

RESPONSE TO: Kumar R, Bhatia A. Common variable immunodeficiency in adults: current diagnostic protocol and laboratory measures. Expert Rev. Clin. Immunol. 10(2), 000-000 (2014).

Comparison of diagnostic criteria for common variable immunodeficiency disorder

Common variable immunodeficiency disorders (CVIDs) are the most frequent symptomatic primary immune deficiency condition in adults. The genetic basis for the condition is not known and no single clinical feature or laboratory test can establish the diagnosis; it has been a diagnosis of exclusion. In areas of uncertainty, diagnostic criteria can provide valuable clinical information. Here, we compare the revised European society of immune deficiencies (ESID) registry (2014) criteria with the diagnostic criteria of Ameratunga et al. (2013) and the original ESID/pan American group for immune deficiency (ESID/PAGID 1999) criteria. The ESID/PAGID (1999) criteria either require absent isohemagglutinins or impaired vaccine responses to establish the diagnosis in patients with primary hypogammaglobulinemia. Although commonly encountered, infective and autoimmune sequelae of CVID were not part of the original ESID/PAGID (1999) criteria. Also excluded were a series of characteristic laboratory and histological abnormalities, which are useful when making the diagnosis. The diagnostic criteria of Ameratunga et al. (2013) for CVID are based on these markers. The revised ESID registry (2014) criteria for CVID require the presence of symptoms as well as laboratory abnormalities to establish the diagnosis. Once validated, criteria for CVID will improve diagnostic precision and will result in more equitable and judicious use of intravenous or subcutaneous immunoglobulin therapy.

New diagnostic criteria for common variable immune deficiency (CVID), which may assist with decisions to treat with intravenous or subcutaneous immunoglobulin

Common variable immune deficiency (CVID) is the most frequent symptomatic primary immune deficiency in adults. The standard of care is intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (scIG) therapy. The cause of CVID is currently unknown, and there is no universally accepted definition of CVID. This creates problems in determining which patients will benefit from IVIG/scIG treatment. In this paper, we review the difficulties with the commonly used European Society of Immune Deficiencies (ESID) and the Pan American Group for Immune Deficiency (PAGID) definition of CVID. We propose new criteria for the diagnosis of CVID, which are based on recent scientific discoveries. Improved diagnostic precision will assist with treatment decisions including IVIG/scIG replacement. We suggest that asymptomatic patients with mild hypogammaglobulinaemia are termed hypogammaglobulinaemia of uncertain significance (HGUS). These patients require long-term follow-up, as some will evolve into CVID.

Hypogammaglobulinemia factitia- Munchausen syndrome masquerading as common variable immune deficiency

Background

We describe the first case of a patient with factitious disorder who closely simulated a primary immune deficiency disorder – Common Variable Immune Deficiency (CVID), by surreptitiously ingesting non-steroidal anti-inflammatory agents.

Case description

He was treated with several expensive and potentially dangerous drugs before the diagnosis was established through collateral information. In retrospect he did not meet the proposed new criteria for CVID. These criteria may prove useful in distinguishing cases of CVID from secondary hypogammaglobulinemia.

Conclusion

It is imperative clinicians recognise patients with factitious disorder at the earliest opportunity to prevent iatrogenic morbidity and mortality.

Samter's triad in childhood: a warning for those prescribing NSAIDs

Aspirin-exacerbated respiratory disease (AERD) has been recognized in adults with chronic asthma. Samter's triad is a subset of AERD where adult patients develop nasal polyps, asthma, and sensitivity to aspirin. This condition is thought not to occur before the third decade of life. We report a 13-year-old boy with nasal polyps who suffered a life-threatening exacerbation of asthma during a graded aspirin challenge. Resuscitation required positive pressure ventilation and inotropic support. Our observations confirm that classical Samter's triad can occur in children. We suggest that graded aspirin challenges in children are undertaken in a facility with equipment and staff trained for resuscitation. Consideration should be given to this rare complication when prescribing nonsteroidal anti-inflammatory drugs in the perioperative period. Suspicion of this condition merits referral to an immunologist for desensitization to aspirin.

Variability of memory B cell markers in a cohort of common variable immune deficiency patients over 6 months

Common Variable Immunodeficiency Disorder (CVID) is a complex disorder that predisposes patients to recurrent and severe infections. Immunophenotypic classification schemes were developed to categorize patients with CVID into phenotypic and prognostic groups based on different memory B cell subsets. Whether the B cell subset analysis is stable over time has not been investigated. B cell phenotyping in patients with CVID (n = 15) and sex- and age-matched controls (n = 26) were carried out according to the three B cell classifications. Patients with CVID were evaluated monthly over 6 months. Controls were assessed once during the study. We scored how often each patient was assigned to the same group within each classification. The Freiburg classification assigned patients to the same group at a rate of 73% and the Paris classification at 88%. The EUROclass classification of smB- versus smB+ was at 90%. The two subclassifications [(smB-21low or smB-21norm) and transitional B] were at 87% and 97%, respectively. The level of naïve B cells measured in all patients with CVID during the 6-month evaluation was the most stable B cell subset. We conclude that all classifications systems show considerable variability, but the EUROclass classification was the most reliable scheme for our 15 CVID and 26 healthy cohorts. Our results indicate that phenotypic classifications within CVID will be difficult while there is variability of commonly used assays.

Primary immune deficiency disorders in the South Pacific: the clinical utility of a customized genetic testing program in New Zealand

Primary immune deficiency disorders (PIDs) are a group of diseases associated with a genetic susceptibility to recurrent infections, malignancy, autoimmunity, and allergy. The molecular basis of many of these disorders has been identified in the last two decades. Most are inherited as single gene defects. As discussed in this paper, identifying the underlying genetic defect plays a critical role in many areas-including patient management, diagnosis, identifying atypical presentations, family studies, providing prognostic information, prenatal diagnosis, and defining new diseases. New Zealand is a geographically isolated, developed country in the South Pacific. We have introduced a dedicated customized genetic testing service for PID patients in New Zealand. This accredited diagnostic program offers rapid turnaround times for genetic tests and minimizes the risk of laboratory errors. Here we review the clinical indications for genetic testing for PIDs based on cases referred to the molecular immunology diagnostic service at Auckland City Hospital.

Adverse reactions to food in New Zealand children aged 0-5 years

AIM

The aim of this study was to describe parent/caregiver-reported adverse reactions to food in children aged 0-5 years in New Zealand.

METHOD

A cross-sectional survey was undertaken in clinics conducted by the Royal New Zealand Plunket Society, which is the major healthcare provider for New Zealand's Well Child programme. Parents/caregivers of 110 (65%) children participated.

RESULTS

Of the 44 children who experienced an adverse reaction to food, only four were clinically evaluated and had undergone diagnostic testing. Two other children were hospitalised following systemic symptoms. Neither was tested for food allergy. 18 (16%) children had physician diagnosed eczema.

CONCLUSION

Within the limitations of this small study, the data indicated adverse reactions to foods are a public health concern in New Zealand and may be under investigated even in children with severe symptoms. These children remain at increased risk of continued morbidity. Based on this preliminary study further research on food allergy in New Zealand is warranted.

Anaphylaxis to hyperallergenic functional foods

Background

Food allergy can cause life threatening reactions. Currently, patients with severe food allergy are advised to avoid foods which provoke allergic reactions. This has become increasingly difficult as food proteins are being added to a broader range of consumer products.

Patients and methods

Here we describe our investigations into the allergenicity of a new drink when two cow's milk allergic children suffered anaphylaxis after consuming Wh₂ole^®.

Results

Our studies have shown that in comparison with cow's milk, Wh₂ole^® contains at least three times the concentration of β-lactoglobulin. β-lactoglobulin is one of the dominant allergens in bovine milk.

Conclusions

These studies have shown that modern technology allows the creation of "hyperallergenic" foods. These products have the potential to cause severe reactions in milk allergic persons. Avoiding inadvertent exposure is the shared responsibility of allergic consumers, regulatory authorities and the food industry.

2010 International consensus algorithm for the diagnosis, therapy and management of hereditary angioedema

BACKGROUND

We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) and updated this as Hereditary angioedema: a current state-of-the-art review: Canadian Hungarian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema.

OBJECTIVE

To update the International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema (circa 2010).

METHODS

The Canadian Hereditary Angioedema Network (CHAEN)/Réseau Canadien d'angioédème héréditaire (RCAH) http://www.haecanada.com and cosponsors University of Calgary and the Canadian Society of Allergy and Clinical Immunology (with an unrestricted educational grant from CSL Behring) held our third Conference May 15th to 16th, 2010 in Toronto Canada to update our consensus approach. The Consensus document was reviewed at the meeting and then circulated for review.

RESULTS

This manuscript is the 2010 International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema that resulted from that conference.

CONCLUSIONS

Consensus approach is only an interim guide to a complex disorder such as HAE and should be replaced as soon as possible with large phase III and IV clinical trials, meta analyses, and using data base registry validation of approaches including quality of life and cost benefit analyses, followed by large head-to-head clinical trials and then evidence-based guidelines and standards for HAE disease management.

The clinical utility of molecular diagnostic testing for primary immune deficiency disorders: a case based review

Primary immune deficiency disorders (PIDs) are a group of diseases associated with a genetic predisposition to recurrent infections, malignancy, autoimmunity and allergy. The molecular basis of many of these disorders has been identified in the last two decades. Most are inherited as single gene defects. Identifying the underlying genetic defect plays a critical role in patient management including diagnosis, family studies, prognostic information, prenatal diagnosis and is useful in defining new diseases. In this review we outline the clinical utility of molecular testing for these disorders using clinical cases referred to Auckland Hospital. It is written from the perspective of a laboratory offering a wide range of tests for a small developed country.

Customised molecular diagnosis of primary immune deficiency disorders in New Zealand: an efficient strategy for a small developed country

INTRODUCTION

Primary Immune Deficiency disorders (PIDs) are uncommon conditions, which necessitate urgent diagnosis in order to prevent disabling complications such as bronchiectasis. Timely diagnosis can be life-saving in children with PIDs such as severe combined immune deficiency.

METHODS

A customised molecular diagnostic service was established in New Zealand in 2005. Most patients referred to the service have undergone genetic counselling before blood was drawn for testing. Genomic DNA was extracted and polymerase chain reaction (PCR) performed to amplify genes of interest, followed by DNA sequencing. The DNA sequences were then aligned with wild type sequence using computer software to identify possible mutations.

RESULTS

Mutational analysis was undertaken in 27 probands with suspected PID. Seven causative mutations were identified in these patients. Family studies have been undertaken after genetic counselling.

CONCLUSIONS

Customised genetic testing is a cost-effective and efficient method for PID diagnosis in a small developed country.

Latex glove use by food handlers: the case for nonlatex gloves

There is increasing concern that continued exposure to latex products can predispose individuals, particularly those who are atopic (allergy prone), to latex allergy. Latex allergy as a serious hazard has been well documented in the health care industry. There are also well-documented cases of food handlers who have had allergic reactions after the use of latex gloves. The contamination of food with latex proteins by food handlers using latex gloves can also result in potentially severe allergic reactions in latex-allergic consumers. We review latex allergy and present the case for avoiding latex glove use by food handlers in the food and hospitality industries. Adopting the use of nonlatex gloves has benefits for workers, consumers, and the food industry.

Follicular lymphoma in a X-linked lymphoproliferative syndrome carrier female

X-linked lymphoproliferative (XLP) syndrome is a rare primary immune-deficiency disorder caused by mutations of the SH2D1A or XIAP genes. Males with the disorder are usually in good health until contracting Epstein-Barr virus (EBV) whereupon the majority of patients die from fulminant infectious mononucleosis, lymphoma or hypogammaglobulinaemia. This report describes a female carrier with an XLP phenotype who was retrospectively identified after her grandson died from the disorder. Subsequent genetic testing identified the patient's mother and affected maternal grandmother as XLP carriers. The family's medical records were significant. The proband had lymphoma at ages 2 and 8 and made a full recovery following treatment. Both the maternal grandmother and uncle died of non-Hodgkin's lymphoma. We were concerned that the XLP carrier mother may be predisposed to lymphoma if the normal X chromosome is skewed towards inactivation. The human androgen receptor assay detected random X chromosome inactivation in the carrier mother. EBV was not detected in the lymphoma tissues of the proband and his grandmother, confirming previous findings that EBV is not always associated with lymphoma in XLP. More significantly, our study highlights the importance of identifying XLP in families with a high incidence of lymphoma.