A Markov model to analyze cost-effectiveness of screening for severe combined immunodeficiency (SCID)

Cost-effectiveness of spinal muscular atrophy newborn screening based on real-world data in Belgium

The objective of the study was to assess the cost-effectiveness of real-world spinal muscular atrophy newborn screening followed by treatment. We modeled the lifetime cost-effectiveness of the spinal muscular atrophy newborn screening followed by treatment (screening) compared to treatment without screening (no screening) from the Belgian healthcare perspective. Real-world data, including quality of life, costs, and motor development data, were collected on 12 patients identified by screening and 43 patients identified by their symptoms. "Screening" was associated with slightly higher healthcare costs (€ 6,858,061 vs. € 6,738,120) but more quality-adjusted life years (QALY) (40.95 vs. 20.34) compared to "no screening", leading to an incremental cost-effectiveness ratio of € 5,820 per QALY gained. "Screening" was dominant from a societal perspective (negative incremental costs: € -14,457; incremental QALY = 20.61), when incorporating the burden on caregivers (negative incremental costs = € -74,353; incremental QALY = 27.51), and when the treatment was chosen by the parents (negative incremental costs = € -2,596,748; incremental QALY = 20.61). Spinal muscular atrophy newborn screening coupled with early treatment is thus cost-effective compared with late treatment following clinical diagnosis and is dominant when societal perspective, caregiver burden, and treatment based on parental preference were considered.

Severe Combined Immunodeficiency (SCID) and Its New Treatment Modalities

Severe combined immunodeficiency (SCID) is a rare condition with very high mortality. SCID is mainly caused by the multiple mutations of genes affecting the entire immune cells. Children with this disease are born with an impaired immune system. The child appears healthy but the consequences of the impaired immune system lead to various secondary infections such as meningeal infections and respiratory infections further leading to consolidation, diarrhea, inflammation of skin and other systemic diseases. Severe combined immunodeficiency is also known as "bubble boy disease" or "living in the bubble" syndrome, as in early days for treatment the physicians decided to completely isolate them until they got the perfect match for the bone marrow transplantation. It is one of the pediatric emergencies and is to be treated as soon as possible. SCID involves multiple genes which leads to makes diagnosis of the disease cumbersome. In early years many infants were diagnosed almost after half a year and in severe conditions which led to the decrease in the survival rate of the children. But now due to advanced newborn screening modalities and other monitoring systems it can be diagnosed as early as within three months of age. The various treatment modalities include hematopoietic stem cell transplantation, gene therapy, enzyme replacement therapy and chemotherapy. This narrative review article describes about the severe combined immunodeficiency and its newer treatment modalities.

Efficient screening strategies for severe combined immunodeficiencies in newborns

INTRODUCTION

Severe combined immunodeficiency (SCID) is one of the most severe forms of inborn errors of immunity (IEI), affecting both cellular and humoral immunity. Without curative treatment such as hematopoietic stem cell transplantation or gene therapy, affected infants die within the first year of life. Due to the severity of the disease, asymptomatic status early in life, and improved survival in the absence of pretransplant infections, SCID was considered a suitable candidate for newborn screening (NBS).

AREAS COVERED

Many countries have introduced SCID screening based on T-cell receptor excision circle (TREC) detection in their NBS programs. Screening an entire population is a radical departure from previous paradigms in the field of immunology. Efficient screening strategies are cost-efficient and balance high sensitivity while preventing high numbers of referrals. NBS for SCID is accompanied by (actionable) secondary findings, but many NBS programs have optimized their screening strategy by adjusting algorithms or including second-tier tests. Harmonization of screening terminology is of great importance for international shared learning.

EXPERT OPINION

The expansion of NBS is driven by the development of new test modalities and treatment options. In the near future, other techniques such as next-generation sequencing will pave the way for NBS of other IEI. Exciting times await for population-based screening programs.

Expanding the Australian Newborn Blood Spot Screening Program using genomic sequencing: do we want it and are we ready?

Since the introduction of genome sequencing in medicine, the factors involved in deciding how to integrate this technology into population screening programs such as Newborn Screening (NBS) have been widely debated. In Australia, participation in NBS is not mandatory, but over 99.9% of parents elect to uptake this screening. Gauging stakeholder attitudes towards potential changes to NBS is vital in maintaining this high participation rate. The current study aimed to determine the knowledge and attitudes of Australian parents and health professionals to the incorporation of genomic sequencing into NBS programs. Participants were surveyed online in 2016 using surveys adapted from previous studies. The majority of parents (90%) self-reported some knowledge of NBS, with 77% expressing an interest in NBS using the new technology. This was significantly lower than those who would utilise NBS using current technologies (99%). Although, many health professionals (62%) felt that new technologies should currently not be used as an adjunct to NBS, 79% foresaw the use of genomic sequencing in NBS by 2026. However, for genomic sequencing to be considered, practical and technical challenges as well as parent information needs were identified including the need for accurate interpretation of data; pre-and post-test counselling; and appropriate parental consent and opt-out process. Therefore, although some support for implementing genomic sequencing into Australian NBS does exist, there is a need for further investigation into the ethical, social, legal and practical implications of introducing this new technology as a replacement to current NBS methods.

Genomic-Based Newborn Screening for Inborn Errors of Immunity: Practical and Ethical Considerations

Inborn errors of immunity (IEI) are a group of over 450 genetically distinct conditions associated with significant morbidity and mortality, for which early diagnosis and treatment improve outcomes. Newborn screening for severe combined immunodeficiency (SCID) is currently underway in several countries, utilising a DNA-based technique to quantify T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC). This strategy will only identify those infants with an IEI associated with T and/or B cell lymphopenia. Other severe forms of IEI will not be detected. Up-front, first-tier genomic-based newborn screening has been proposed as a potential approach by which to concurrently screen infants for hundreds of monogenic diseases at birth. Given the clinical, phenotypic and genetic heterogeneity of IEI, a next-generation sequencing-based newborn screening approach would be suitable. There are, however, several ethical, legal and social issues which must be evaluated in detail prior to adopting a genomic-based newborn screening approach, and these are discussed herein in the context of IEI.

Lessons Learned From Five Years of Newborn Screening for Severe Combined Immunodeficiency in Israel

BACKGROUND

Implementation of newborn screening (NBS) programs for severe combined immunodeficiency (SCID) have advanced the diagnosis and management of affected infants and undoubtedly improved their outcomes. Reporting long-term follow-up of such programs is of great importance.

OBJECTIVE

We report a 5-year summary of the NBS program for SCID in Israel.

METHODS

Immunologic and genetic assessments, clinical analyses, and outcome data from all infants who screened positive were evaluated and summarized.

RESULTS

A total of 937,953 Guthrie cards were screened for SCID. A second Guthrie card was requested on 1,169 occasions (0.12%), which resulted in 142 referrals (0.015%) for further validation tests. Flow cytometry immune-phenotyping, T cell receptor excision circle measurement in peripheral blood, and expression of TCRVβ repertoire for the validation of positive cases revealed a specificity and sensitivity of 93.7% and 75.9%, respectively, in detecting true cases of SCID. Altogether, 32 SCID and 110 non-SCID newborns were diagnosed, making the incidence of SCID in Israel as high as 1:29,000 births. The most common genetic defects in this group were associated with mutations in DNA cross-link repair protein 1C and IL-7 receptor α (IL-7Rα) genes. No infant with SCID was missed during the study time. Twenty-two SCID patients underwent hematopoietic stem cell transplantation, which resulted in a 91% survival rate.

CONCLUSIONS

Newborn screening for SCID should ultimately be applied globally, specifically to areas with high rates of consanguineous marriages. Accumulating data from follow-up studies on NBS for SCID will improve diagnosis and treatment and enrich our understanding of immune development in health and disease.

Population-based screening of newborns: Findings from the newborn screening expansion study (part two)

Rapid advances in genomic technologies to screen, diagnose, and treat newborns will significantly increase the number of conditions in newborn screening (NBS). We previously identified four factors that delay and/or complicate NBS expansion: 1) variability in screening panels persists; 2) the short duration of pilots limits information about interventions and health outcomes; 3) recent recommended uniform screening panel (RUSP) additions are expanding the definition of NBS; and 4) the RUSP nomination and evidence review process has capacity constraints. In this paper, we developed a use case for each factor and suggested how model(s) could be used to evaluate changes and improvements. The literature on models was reviewed from a range of disciplines including system sciences, management, artificial intelligence, and machine learning. The results from our analysis highlighted that there is at least one model which could be applied to each of the four factors that has delayed and/or complicate NBS expansion. In conclusion, our paper supports the use of modeling to address the four challenges in the expansion of NBS.

Modelling the Cost-Effectiveness and Budget Impact of a Newborn Screening Program for Spinal Muscular Atrophy and Severe Combined Immunodeficiency

Spinal muscular atrophy (SMA) and severe combined immunodeficiency (SCID) are rare, inherited genetic disorders with severe mortality and morbidity. The benefits of early diagnosis and initiation of treatment are now increasingly recognized, with the most benefits in patients treated prior to symptom onset. The aim of the economic evaluation was to investigate the costs and outcomes associated with the introduction of universal newborn screening (NBS) for SCID and SMA, by generating measures of cost-effectiveness and budget impact. A stepwise approach to the cost-effectiveness analyses by decision analytical models nested with Markov simulations for SMA and SCID were conducted from the government perspective. Over a 60-year time horizon, screening every newborn in the population and treating diagnosed SCID by early hematopoietic stem cell transplantation and SMA by gene therapy, would result in 95 QALYs gained per 100,000 newborns, and result in cost savings of USD 8.6 million. Sensitivity analysis indicates 97% of simulated results are considered cost-effective against commonly used willingness-to-pay thresholds. The introduction of combined NBS for SCID and SMA is good value for money from the long-term clinical and economic perspectives, representing a cost saving to governments in the long-term, as well as improving and saving lives.

Economic Evaluation of Newborn Screening for Severe Combined Immunodeficiency

Evidence on the cost-effectiveness of newborn screening (NBS) for severe combined immunodeficiency (SCID) in the Australian policy context is lacking. In this study, a pilot population-based screening program in Australia was used to model the cost-effectiveness of NBS for SCID from the government perspective. Markov cohort simulations were nested within a decision analytic model to compare the costs and quality-adjusted life-years (QALYs) over a time horizon of 5 and 60 years for two strategies: (1) NBS for SCID and treat with early hematopoietic stem cell transplantation (HSCT); (2) no NBS for SCID and treat with late HSCT. Incremental costs were compared to incremental QALYs to calculate the incremental cost-effectiveness ratios (ICER). Sensitivity analyses were performed to assess the model uncertainty and identify key parameters impacting on the ICER. In the long-term over 60 years, universal NBS for SCID would gain 10 QALYs at a cost of US $0.3 million, resulting in an ICER of US$33,600/QALY. Probabilistic sensitivity analysis showed that more than half of the simulated ICERs were considered cost-effective against the common willingness-to-pay threshold of A$50,000/QALY (US$35,000/QALY). In the Australian context, screening for SCID should be introduced into the current NBS program from both clinical and economic perspectives.

Modern diagnostic capabilities of neonatal screening for primary immunodeficiencies in newborns

Population screening of newborns is an extremely important and informative diagnostic approach that allows early identification of babies who are predisposed to the development of a number of serious diseases. Some of these diseases are known and have effective treatment methods. Neonatal screening enables the early diagnosis and subsequent timely initiation of therapy. This helps to prevent serious complications and reduce the percentage of disability and deaths among newborns and young children. Primary immunodeficiency diseases and primary immunodeficiency syndrome (PIDS) are a heterogeneous group of diseases and conditions based on impaired immune system function associated with developmental defects and characterized by various combinations of recurrent infections, development of autoimmune and lymphoproliferative syndromes (genetic defects in apoptosis, gene mutation Fas receptor or ligand), granulomatous process, and malignant neoplasms. Most of these diseases manifest in infancy and lead to serious illness, disability, and high mortality rates. Until recently, it was impossible to identify children with PIDS before the onset of the first clinical symptoms, which are usually accompanied by complications in the form of severe coinfections of a viral-bacterial-fungal etiology. Modern advances in medical laboratory technology have allowed the identification of children with severe PIDS, manifested by T- and/or B-cell lymphopenia and other disorders of the immune system. This review discusses the main existing strategies and directions used in PIDS screening programs for newborns, including approaches to screening based on excision of T-cell receptors and kappa-recombination excision circles, as well as the potential role and place of next-generation sequencing technology to increase the diagnostic accuracy of these diseases.

Economic Evaluation of Different Screening Strategies for Severe Combined Immunodeficiency Based on Real-Life Data

Although several countries have adopted severe combined immunodeficiency (SCID) into their newborn screening (NBS) program, other countries are still in the decision process of adding this disorder in their program and finding the appropriate screening strategy. This decision may be influenced by the cost(-effectiveness) of these screening strategies. In this study, the cost(-effectiveness) of different NBS strategies for SCID was estimated based on real-life data from a prospective implementation study in the Netherlands. The cost of testing per child for SCID was estimated at EUR 6.36. The cost of diagnostics after screen-positive results was assessed to vary between EUR 985 and 8561 per child dependent on final diagnosis. Cost-effectiveness ratios varied from EUR 41,300 per QALY for the screening strategy with T-cell receptor excision circle (TREC) ≤ 6 copies/punch to EUR 44,100 for the screening strategy with a cut-off value of TREC ≤ 10 copies/punch. The analysis based on real-life data resulted in higher costs, and consequently in less favorable cost-effectiveness estimates than analyses based on hypothetical data, indicating the need for verifying model assumptions with real-life data. The comparison of different screening strategies suggest that strategies with a lower number of referrals, e.g., by distinguishing between urgent and less urgent referrals, are favorable from an economic perspective.

Neonatal Screening for SCID: The French Experience

After it was demonstrated in 2005 that T cell receptor excision circle (TREC) quantification for dried blood spot (DBS) samples on Guthrie cards is an effective means of SCID screening and following several pilot studies, the practice was formally recommended in the US in 2010. More and more countries have adopted it since then. In France, before the health authorities could recommend adding SCID to the list of five diseases that were routinely screened for, feasibility and cost-effectiveness studies had to be conducted with a sufficiently large cohort of neonates. We carried out three such studies: The first sought to verify the effectiveness of the assay. The second, DEPISTREC, evaluated the feasibility of universal SCID screening in France and assessed the clinical benefit and economic advantage it would provide. Through the third study, NeoSKID, still under way and to continue until recommendations are issued, we have been offering SCID screening in the Pays de la Loire region of France. This review briefly describes routine newborn screening (NBS) and management of primary immunodeficiency diseases (PIDs) in France, and then considers the lessons from our studies and the status of SCID screening implementation within the country.

The case for severe combined immunodeficiency (SCID) and T cell lymphopenia newborn screening: saving lives…one at a time

Severe combined immunodeficiency (SCID) is a group of syndromes resulting from genetic defects causing severe deficiency in T cell and B cell function. These conditions are life-threatening and result in susceptibility to serious infections. SCID is often fatal in the first year of life if not detected and properly treated. SCID and related T cell lymphopenias can be detected in newborns by a simple screening test, the T cell receptor excision circle (TREC) assay, using the same dried blood spot samples already collected from newborns to screen for other genetic disorders. The TREC assay facilitates the earliest possible identification of cases of SCID before opportunistic infections, irreversible organ damage, or death, thus allowing for the possibility of curative treatment through hematopoietic stem cell transplant and gene therapy. Infants receiving hematopoietic stem cell transplant in the first few months of life, after being identified through screening, have a high probability of survival (95-100%), along with lower morbidity. The TREC assay has proven to have outstanding specificity and sensitivity to accurately identify almost all infants with SCID (the primary targets) as well as additional infants having other select immunologic abnormalities (secondary targets). The TREC assay is inexpensive and has been effectively integrated into many public health programs. Without timely treatment, SCID is a fatal disease that causes accrual of exorbitant healthcare costs even in just 1 year of life. The cost of care for just one infant with SCID, not diagnosed through newborn screening, could be more than the cost of screening for an entire state or regional population. Continued implementation of TREC screening will undoubtedly enhance early diagnosis, application of treatment, and healthcare cost savings. The Jeffrey Modell Foundation helped initiate newborn screening for SCID in the USA in 2008 and continues its efforts to advocate for SCID screening worldwide. Today, all 50 states and Puerto Rico are screening for SCID and T cell lymphopenia, with 27 million newborns screened to date, and hundreds diagnosed and treated. Additionally, there are at least 20 countries around the world currently conducting screening for SCID at various stages. Newborn screening for SCID and related T cell lymphopenia is cost-effective, and most importantly, it is lifesaving and allows children with SCID the opportunity to live a healthy life.

Challenges in Assessing the Cost-Effectiveness of Newborn Screening: The Example of Congenital Adrenal Hyperplasia

Generalizing about the cost-effectiveness of newborn screening (NBS) is difficult due to the heterogeneity of disorders included in NBS panels, along with data limitations. Furthermore, it is unclear to what extent evidence about cost-effectiveness should influence decisions to screen for specific disorders. Screening newborns for congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can serve as a useful test case, since there is no global consensus on whether CAH should be part of NBS panels. Published and unpublished cost-effectiveness analyses of CAH screening have yielded mixed findings, largely due to differences in methods and data sources for estimating health outcomes and associated costs of early versus late diagnosis as well as between-country differences. Understanding these methodological challenges can help inform future analyses and could also help interested policymakers interpret the results of economic evaluations.

Review: Why screen for severe combined immunodeficiency disease?

Newborn screening for severe combined immunodeficiency (SCID) is now routinely performed in many countries across Europe and around the world. The number of T-cell receptor excision circles (TRECs) reflects T cell levels. TREC quantification is possible using dried blood spot (DBS) samples already collected from newborns to screen for other conditions. This method is very sensitive and highly specific. Data in the literature show that the survival rate for children with SCID is much higher when the disease is detected through early screening, as opposed to a later diagnosis. Newborns diagnosed with SCID may receive the appropriate care quickly, before the onset of serious infectious complications, which raises survival rates, improves quality of life, and limits side effects and treatment costs. At the request of the French Ministry of Health, France's National Authority for Health (Haute Autorité de Santé) is expected to issue recommendations on this topic soon. The nationwide DEPISTREC study, involving 48 maternity units across France, showed that routine SCID screening is feasible and effective. Such screening offers the additional benefit of also diagnosing non-SCID lymphopenia within the infant population.

Newborn Screening through TREC, TREC/KREC System for Primary Immunodeficiency with limitation of TREC/KREC. Comprehensive Review

INTRODUCTION

Newborn screening (NBS) by quantifying T cell receptor excision circles (TRECs) and Kappa receptor excision circles in neonatal dried blood spots (DBS) enables early diagnosis of different types of primary immune deficiencies. Global newborn screening for PID, using an assay to detect T-cell receptor excision circles (TREC) in dried blood spots (DBS), is now being performed in all states in the United States. In this review, we discuss the development and outcomes of TREC, TREC/KREC combines screening, and continued challenges to implementation.

OBJECTIVE

To review the diagnostic performance of published articles for TREC and TREC/ KREC based NBS for PID and its different types.

METHODS

Different research resources were used to get an approach for the published data of TREС and KREC based NBS for PID like PubMed, Scopus, Google Scholar, Research gate EMBASE. We extracted TREC and KREC screening Publisher with years of publication, content and cut-off values, and a number of retests, repeat DBS, and referrals from the different published pilot, pilot cohort, Case series, and cohort studies.

RESULTS

We included the results of TREC, combined TREC/KREC system based NBS screening from different research articles, and divided these results between the Pilot studies, case series, and cohort. For each of these studies, different parameter data are excluded from different articles. Thirteen studies were included, re-confirming 89 known SCID cases in case series and reporting 53 new SCID cases in 3.15 million newborns. Individual TREC contents in all SCID patients were <25 TRECs/μl (except in those evaluated with the New York State assay).

CONCLUSION

TREC and KREC sensitivity for typical SCID and other types of PID was 100 %. It shows its importance and anticipating the significance of implementation in different undeveloped and developed countries in the NBS program in upcoming years. Data adapting the screening algorithm for pre-term/ill infants reduce the amount of false-positive test results.

Cost and impact of early diagnosis in primary immunodeficiency disease: A literature review

BACKGROUND

New, innovative, costly diagnostic methods for patients with primary immunodeficiencies (PID) demand upfront insight into their potential cost savings and added value for individual patients. As such, high quality, comparable economic evaluations are of utmost importance to enable informed decisions. The objective of this review was therefore to create an extensive overview of current costing studies and potential cost savings of early diagnosis in primary immunodeficiency disease.

METHODS

A literature search in PubMed was conducted and studies involving any form of costing study in the field of PIDs were included. Of the included studies, study characteristics, cost parameters and benefits of early diagnosis were extracted and outlined in separate tables.

RESULTS

Twenty two studies met the inclusion criteria and were included in the review. The papers were categorized according to their subject: neonatal screening for severe combined immunodeficiency (SCID), Ig replacement therapies and studies reporting on costs of general or specific PIDs. Within and between these groups variability in reported costing characteristics was observed. In studies that reported cost savings pre- and post-diagnosis, cost savings ranged from 6500 to 108,463 USD of total costs per patient.

CONCLUSION

This literature review shows that, regardless of what aspect of PIDs has been studied, in nearly all cases early diagnosis reduces health care consumption and leads to better health outcomes for patients with PIDs. We found considerable variability in costing characteristics of economic evaluations of PID patients, which hampers the comparability of outcomes. More effort is needed to create uniformity and define cost parameters in economic evaluations in the field of PIDs, facilitating further prospective research to extensively assess the benefits of early diagnosis.

Simple Test, Complex System: Multifaceted Views of Newborn Screening Science, Technology, and Policy

Newborn screening (NBS) is a public health service provided for all babies born in the United States and in most countries of the developed world. A series of tests are applied to the blood taken from newborn babies to detect genetic and metabolic disorders that can be treated if identified early. With early treatment and therapy, the affected babies can usually live a normal, healthy life. Timing for sampling, testing, and reporting is vital for NBS to function as an effective system. In order to be an effective system, the evolution of science, technology, and policy gradually had to come into a synchronous partnership, where the discovery of new genetic disorders led to timely development of technology for screening, which is supported by policy and implemented into practice. The timely "dance" of these partnerships in an era of personalized health and medicine forms the integrated approach supporting NBS. This review will include a brief history of scientific development, policymaking, and the economic consideration in the expansion of the NBS.

Molecular Diagnosis of Inherited Immune Disorders

Primary immunodeficiency diseases are a heterogeneous group of rare inherited disorders of innate or adaptive immune system function. Patients with primary immunodeficiencies typically present with recurrent and severe infections in infancy or young adulthood. More recently, the co-occurrence of autoimmune, benign lymphoproliferative, atopic, and malignant complications has been described. The diagnosis of a primary immunodeficiency disorder requires a thorough assessment of a patient's underlying immune system function. Historically, this has been accomplished at the time of symptomatic presentation by measuring immunoglobulins, complement components, protective antibody titers, or immune cell counts in the peripheral blood. Although these data can be used to critically assess the degree of immune dysregulation in the patient, this approach fall short in at least 2 regards. First, this assessment often occurs after the patient has suffered life-threatening infectious or autoinflammatory complications. Second, these data fail to uncover an underlying molecular cause of the patient's primary immune dysfunction, prohibiting the use of molecularly targeted therapeutic interventions. Within the last decade, the field of primary immunodeficiency diagnostics has been revolutionized by 2 major molecular advancements: (1) the onset of newborn screening in 2008, and (2) the onset of next-generation sequencing in 2010. In this article, the techniques of newborn screening and next-generation sequencing are reviewed and their respective impacts on the field of primary immunodeficiency disorders are discussed with a specific emphasis on severe combined immune deficiency and common variable immune deficiency.

A Cost-Effectiveness Analysis of Newborn Screening for Severe Combined Immunodeficiency in the UK

Severe combined immunodeficiency (SCID) can be detected through newborn bloodspot screening. In the UK, the National Screening Committee (NSC) requires screening programmes to be cost-effective at standard UK thresholds. To assess the cost-effectiveness of SCID screening for the NSC, a decision-tree model with lifetable estimates of outcomes was built. Model structure and parameterisation were informed by systematic review and expert clinical judgment. A public service perspective was used and lifetime costs and quality-adjusted life years (QALYs) were discounted at 3.5%. Probabilistic, one-way sensitivity analyses and an exploratory disbenefit analysis for the identification of non-SCID patients were conducted. Screening for SCID was estimated to result in an incremental cost-effectiveness ratio (ICER) of £18,222 with a reduction in SCID mortality from 8.1 (5-12) to 1.7 (0.6-4.0) cases per year of screening. Results were sensitive to a number of parameters, including the cost of the screening test, the incidence of SCID and the disbenefit to the healthy at birth and false-positive cases. Screening for SCID is likely to be cost-effective at £20,000 per QALY, key uncertainties relate to the impact on false positives and the impact on the identification of children with non-SCID T Cell lymphopenia.

Global report on primary immunodeficiencies: 2018 update from the Jeffrey Modell Centers Network on disease classification, regional trends, treatment modalities, and physician reported outcomes

Primary immunodeficiencies (PI) are genetic defects of the immune system that result in chronic, serious, and often life-threatening infections, if not diagnosed and treated. Many patients with PI are undiagnosed, underdiagnosed, or misdiagnosed. In fact, recent studies have shown that PI may be more common than previously estimated and that as many as 1% of the population may be affected with a PI when all types and varieties are considered. In order to raise awareness of PI with the overall goal of reducing associated morbidity and mortality, the Jeffrey Modell Foundation (JMF) established a network of specialized centers that could better identify, diagnose, treat, and follow patients with PI disorders. Over the past decade, the Jeffrey Modell Centers Network (JMCN) has provided the infrastructure to accept referrals, provide diagnosis, and offer treatments. Currently, the network consists of 792 Expert Physicians at 358 institutions, in 277 cities, and 86 countries spanning 6 continents. JMF developed an annual survey for physician experts within the JMCN, using the categories and gene defects identified by the International Union of Immunological Societies Expert Committee for the Classification of PI, to report on the number of patients identified with PI; treatment modalities, including immunoglobulins, transplantation, and gene therapy; and data on gender and age. Center Directors also provided physician-reported outcomes and differentials pre- and post-diagnosis. The current physician-reported data reflect an increase in diagnosed patients, as well as those receiving treatment. Suspected patients are being identified and referred so that they can receive early and appropriate diagnosis and treatment. The significant increase in patients identified with a PI is due, in part, to expanding education and awareness initiatives, newborn screening, and the expansion of molecular diagnosis and sequencing. To our knowledge, this is the most extensive single physician report on patients with PI around the world.

Cost-effectiveness of newborn screening for severe combined immunodeficiency

Severe combined immunodeficiency (SCID) is a condition that often results in severe infections and death at young age. Early detection shortly after birth, followed by treatment before infections occur, largely increases the chances of survival. As the incidence of SCID is low, assessing cost-effectiveness of adding screening for SCID to the newborn screening program is relevant for decision making. Lifetime costs and effects of newborn screening for SCID were compared to a situation without screening in the Netherlands in a decision analysis model. Model parameters were based on literature and expert opinions. Sensitivity analyses were performed. Due to earlier detection, the number of deaths due to SCID per 100,000 children was assessed to decrease from 0.57 to 0.23 and a number of 11.7 quality adjusted life-years (QALYs) gained was expected. Total yearly healthcare costs, including costs of screening, diagnostics, and treatment, were €390,800 higher in a situation with screening compared to a situation without screening, resulting in a cost-utility ratio of €33,400 per QALY gained.Conclusion: Newborn screening for SCID might be cost-effective. However, there is still a lot of uncertainty around the cost-effectiveness estimate. Pilot screening projects are warranted to obtain more accurate estimates for the European situation. What is Known: • Severe combined immunodeficiency (SCID) is a condition that often results in severe infections and death at a young age. • As the incidence of SCID is low, assessing cost-effectiveness of adding screening for SCID to the newborn screening program is needed. What is New: • Newborn screening for SCID is expected to reduce mortality from 0.57 to 0.23 per 100,000 children at additional healthcare costs of €390,800. The cost-utility ratio is €33,400 per QALY gained. • Due to large uncertainty around cost-effectiveness estimates, pilot screening projects are warranted for Europe.

Societal value of newborn screening for severe combined immune deficiency in Arkansas: An economic analysis

Newborn screening (NBS) is a public health program that detects genetic conditions in neonates enabling treatment before clinical symptoms manifest. Severe combined immune deficiency (SCID) is a primary immune deficiency found in the absence of functioning T and B lymphocytes. Hematopoietic cell transplantation is a potentially curative treatment if received within the first 42 months of life; without treatment, this condition is fatal in the first 2 years of life due to severe opportunistic infections. SCID was added to the recommended uniform panel of conditions for inclusion in state NBS programs in 2010. This manuscript examines the societal costs and benefits of NBS for SCID in Arkansas and implications to health services and social welfare. Total cost per year of all NBS for SCID and resulting early treatment for one patient with SCID in Arkansas is estimated at $1,078,714. Cost of late treatment of one patient with SCID is estimated at $1.43 million. Based on an expected diagnosis of one patient per year in Arkansas, this results in an estimated net cost savings for NBS for SCID in Arkansas of $351,286 per year. Based on cost-effectiveness analysis, NBS for SCID in Arkansas is cost-effective, with higher societal benefit than cost.

Clinical and economic aspects of newborn screening for severe combined immunodeficiency: DEPISTREC study results

PURPOSE

Severe combined immunodeficiency (SCID) refers to a group of genetic disorders characterized by greatly compromised cellular and humoral immunity. Children with SCID are asymptomatic at birth, but they die from infections within the first months of life if not treated. Quantification of T-cell receptor excision circles is an extremely sensitive screening method for detecting newborns who may have SCID.The goal of the DEPISTREC study was to evaluate the feasibility of nationwide newborn screening for severe T-cell lymphopenia in France as well as its economic and clinical utility.

METHODS

The test universally used for neonatal screening for SCID was the quantification of TRECs on Guthrie cards. We compared a group of 190,517 babies from 48 maternities across the country who underwent newborn SCID screening with a control group of 1.4 million babies out of whom 28 were diagnosed with SCID without such screening during the course of the study.

RESULTS

Within the screening group, 62 babies were found to be lymphopenic, including three with SCID. The cost of screening ranged from 4.7€ to €8.15 per newborn. The average 18-month cost was €257,574 vs €204,697 in the control group.

CONCLUSIONS

In this large-scale study, we demonstrate that routine SCID screening is feasible and effective. This screening offers the additional benefit of aiding in the diagnosis of non-SCID lymphopenia. Economic evaluation allowed us to calculate the cost per test. Newborn screening may also prevent death by SCID before any curative treatment can be administered. The difference in cost between screened and control children could not be ascertained because of the very low numbers and death of one of the children tested.

Newborn screening for severe combined immunodeficiency and T-cell lymphopenia

The development of a T cell receptor excision circle (TREC) assay utilizing dried blood spots (DBS) made possible universal newborn screening (NBS) for severe combined immunodeficiency (SCID) as a public health measure. Upon being flagged by an abnormal screening test in a SCID screening program, an infant can receive further diagnostic testing for SCID in the neonatal period, prior to onset of infectious complications, to permit immediate institution of protective measures and definitive, life-saving treatment to establish a functional immune system. SCID screening is now the accepted standard of care in state public health departments across the United States, and it is being adopted in many countries. It has proven effective, with infants having this otherwise inapparent but serious, rare disorder achieving survival and immune reconstitution. In addition to bringing to attention infants with the primary screening target diseases, typical SCID and leaky SCID (due to hypomorphic mutations in known SCID genes), the NBS assay for insufficient TRECs in DBS also reveals infants with non-SCID T lymphopenic conditions. Experience has accumulated regarding the range and limitations of diagnoses of newborns with low TRECs and low T cells. Previously unknown immune defects have been discovered, as well as conditions not formerly recognized to have low T cells in the neonatal period.

Introducing Newborn Screening for Severe Combined Immunodeficiency (SCID) in the Dutch Neonatal Screening Program

The implementation of newborn screening for severe combined immunodeficiency (SCID) in the Netherlands is a multifaceted process in which several parties are involved. The Dutch Ministry of Health adopted the advice of the Dutch Health Council to include SCID in the Dutch newborn screening program in 2015. As newborn screening for SCID is executed with a new, relatively expensive assay for the Dutch screening laboratory, an implementation pilot study is deemed instrumental for successful implementation. A feasibility study was performed in which the practicalities and preconditions of expanding the newborn screening program were defined. Cost-effectiveness analysis (CEA) indicated that SCID screening in the Netherlands might be cost-effective, recognizing that there are still many uncertainties in the variables underlying the CEA. Data and experience of the pilot study should provide better estimates of these parameters, thus enabling the actualization of CEA results. Prior to the implementation pilot study, a comparison study of two commercially available SCID screening assays was performed. A prospective implementation pilot study or so-called SONNET study (SCID screening research in the Netherlands with TRECs) started in April 2018 and allows the screening for SCID of all newborns in three provinces of the Netherlands for one year. Based on the results of the SONNET study, the Dutch Ministry of Health will make a final decision about national implementation of newborn screening for SCID in the Netherlands.

Newborn Screening for Severe Combined Immunodeficiency

PURPOSE OF REVIEW

This review provides a brief history of newborn screening (NBS) for severe combined immunodeficiency (SCID), discusses the theoretical basis for the T cell receptor excision circle (TREC) assay, highlights the results of recent studies using the TREC, and provides practical advice for the evaluation of infants with an abnormal TREC assay.

RECENT FINDINGS

Currently, all but three states perform NBS for SCID in the USA. NBS using the TREC assay is highly sensitive in identifying infants with SCID and may also identify infants with T cell lymphopenia due to other causes such as congenital syndromes, multiple congenital anamolies, and some combined immunodeficiencies. Regardless of the genetic etiology, all forms of SCID are characterized by a severe deficiency of naïve T cells. TRECs are a biomarker of newly formed, naïve T cells that have recently left the thymus. Consequently, the TREC assay identifies infants with SCID and other causes of severe T cell lymphopenia.

A Droplet Digital PCR Method for Severe Combined Immunodeficiency Newborn Screening

Severe combined immunodeficiency (SCID) benefits from early intervention via hematopoietic cell transplantation to reverse T-cell lymphopenia (TCL). Newborn screening (NBS) programs use T-cell receptor excision circle (TREC) levels to detect SCID. Real-time quantitative PCR is often performed to quantify TRECs in dried blood spots (DBSs) for NBS. Yet, real-time quantitative PCR has inefficiencies necessitating normalization, repeat analyses, or standard curves. To address these issues, we developed a multiplex, droplet digital PCR (ddPCR) method for measuring absolute TREC amounts in one DBS punch. TREC and RPP30 levels were simultaneously measured with a Bio-Rad AutoDG and QX200 ddPCR system. DBSs from 610 presumed-normal, 29 lymphocyte-profiled, and 10 clinically diagnosed infants (1 X-linked SCID, 1 RAG1 Omenn syndrome, and other conditions) were tested. Control infants showed 14 to 474 TREC copies/μL blood. SCID infants, and other TCL conditions, had ≤15 TREC copies/μL. The ddPCR lower limit of quantitation was 14 TREC copies/μL, and the limit of detection was 4 TREC copies/μL. Intra-assay and interassay imprecision was <20% CV for DBSs at 54 to 60 TREC copies/μL. Testing 29 infants with known lymphocyte profiles resulted in a sensitivity of 88.9% and a specificity of 100% at TRECs <20 copies/μL. We developed a multiplex ddPCR method for the absolute quantitation of DBS TRECs that can detect SCID and other TCL conditions associated with absent or low TRECs and validated this method for NBS.

A Novel Homozygous JAK3 Mutation Leading to T-B+NK- SCID in Two Brazilian Patients

We report a novel homozygous JAK3 mutation in two female Brazilian SCID infants from two unrelated kindreds. Patient 1 was referred at 2 months of age due to a family history of immunodeficiency and the appearance of a facial rash. The infant was screened for TRECs (T-cell receptor excision circles) and KRECs (kappa-deleting recombination excision circles) for the assessment of newly formed naïve T and B cells respectively, which showed undetectable TRECs and normal numbers of KRECs. Lymphocyte immunophenotyping by flow cytometry confirmed the screening results, revealing a T-B+NK- SCID. The patient underwent successful HSCT. Patient 2 was admitted to an intensive care unit at 8 months of age with severe pneumonia, BCGosis, and oral moniliasis; she also had a positive family history for SCID but newborn screening was not performed at birth. At 10 months of age she was diagnosed as a T-B+NK- SCID and underwent successful HSCT. JAK3 sequencing revealed the same homozygous missense mutation (c.2350G>A) in both patients. This mutation affects the last nucleotide of exon 17 and it is predicted to disrupt the donor splice site. cDNA sequencing revealed skipping of exon 17 missing in both patients, confirming the predicted effect on mRNA splicing. Skipping of exon 17 leads to an out of frame deletion of 151 nucleotides, frameshift and creation of a new stop codon 60 amino acids downstream of the mutation resulting in a truncated protein which is likely nonfunctional.

Primary immunodeficiencies worldwide: an updated overview from the Jeffrey Modell Centers Global Network

Primary immunodeficiencies (PI) are defects of the immune system that cause severe, sometimes life-threatening, infections if not diagnosed and treated appropriately. Many patients with PI are undiagnosed, under-diagnosed, or misdiagnosed. To raise awareness and assure earliest diagnosis, appropriate treatment, and proper care management, the Jeffrey Modell Foundation (JMF) implemented a physician education and public awareness program beginning in 2003. Data are requested annually from physician experts within the Jeffrey Modell Centers Network (JMCN), consisting of 602 expert physicians, at 253 academic institutions, in 206 cities, and 84 countries spanning six continents. Center Directors reported on patients' specific PI defects and treatment modalities including immunoglobulins, transplantation, and gene therapy as well as data on gender and age. Center Directors also provided physician-reported patient outcomes as well as pre- and post-diagnosis differences. Costs were assigned to these factors. In collaboration with the Network, JMF advocated, funded, and implemented population-based newborn screening for severe combined immunodeficiency and T cell lymphopenia, covering 96.2 % of all newborns in the US. Finally, 21 JMF Centers participated in a polio surveillance study of patients with PI who either received or have been exposed to the oral polio vaccine. These initiatives have led to an overall better understanding of the immune system and will continue to improve quality of life for those with PI.

First Year of Israeli Newborn Screening for Severe Combined Immunodeficiency-Clinical Achievements and Insights

Severe combined immunodeficiency (SCID), the most severe form of T cell immunodeficiency, is detectable through quantification of T cell receptor excision circles (TRECs) in dried blood spots obtained at birth. Herein, we describe the results of the first year of the Israeli SCID newborn screening (NBS) program. This important, life-saving screening test is available at no cost for every newborn in Israel. Eight SCID patients were diagnosed through the NBS program in its first year, revealing an incidence of 1:22,500 births in the Israeli population. Consanguine marriages and Muslim ethnic origin were found to be a risk factor in affected newborns, and a founder effect was detected for both IL7Rα and DCLRE1C deficiency SCID. Lymphocyte subset analysis and TREC quantification in the peripheral blood appear to be sufficient for confirmation of typical and leaky SCID and ruling out false positive (FP) results. Detection of secondary targets (infants with non-SCID lymphopenia) did not significantly affect the management or outcomes of these infants in our cohort. In the general, non-immunodeficient population, TREC rises along with gestational age and birth weight, and is significantly higher in females and the firstborn of twin pairs. Low TREC correlates with both gestational age and birth weight in extremely premature newborns. Additionally, the rate of TREC increase per week consistently accelerates with gestational age. Together, these findings mandate a lower cutoff or a more lenient screening algorithm for extremely premature infants, in order to reduce the high rate of FPs within this group. A significant surge in TREC values was observed between 28 and 30 weeks of gestation, where median TREC copy numbers rise by 50% over 2 weeks. These findings suggest a maturational step in T cell development around week 29 gestation, and imply moderate to late preterms should be screened with the same cutoff as term infants. The SCID NBS program is still in its infancy, but is already bearing fruit in the early detection and improved outcomes of children with SCID in Israel and other countries.

Haematopoietic stem cell transplantation for severe combined immunodeficiency: Long-term health outcomes and patient perspectives

AIM

To examine the long-term follow-up and health outcomes of patients who have undergone haematopoietic stem cell transplant (HSCT) for severe combined immunodeficiency (SCID).

METHODS

Through a structured questionnaire, we examined follow-up arrangements and long-term health outcomes in 22 children who have had a successful HSCT for SCID during the period of 1984-2012 at the Sydney Children's Hospital, Sydney, Australia.

RESULTS

Most children considered themselves healthy and 'cured' from SCID. Whilst many children enjoy relatively good bio-social health outcomes, specific negative health outcomes and absenteeism from school were perceived negatively. Two-thirds of children see their general practitioner or specialist regularly; however, there did not appear to be consistency with the nature of this follow-up.

CONCLUSION

The findings from our study highlight the complex bio-psychosocial health needs of post-HSCT SCID children and encourage SCID centres to consider a multidisciplinary approach to their follow-up. Further studies into the determinants of patients' perceptions of their health are needed.

The Use of Economic Evaluation to Inform Newborn Screening Policy Decisions: The Washington State Experience

POLICY POINTS

Newborn screening not only saves lives but can also yield net societal economic benefit, in addition to benefits such as improved quality of life to affected individuals and families. Calculations of net economic benefit from newborn screening include the monetary equivalent of avoided deaths and reductions in costs of care for complications associated with late-diagnosed individuals minus the additional costs of screening, diagnosis, and treatment associated with prompt diagnosis. Since 2001 the Washington State Department of Health has successfully implemented an approach to conducting evidence-based economic evaluations of disorders proposed for addition to the state-mandated newborn screening panel.

CONTEXT

Economic evaluations can inform policy decisions on the expansion of newborn screening panels. This article documents the use of cost-benefit models in Washington State as part of the rule-making process that resulted in the implementation of screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and 4 other metabolic disorders in 2004, cystic fibrosis (CF) in 2006, 15 other metabolic disorders in 2008, and severe combined immune deficiency (SCID) in 2014.

METHODS

We reviewed Washington State Department of Health internal reports and spreadsheet models of expected net societal benefit of adding disorders to the state newborn screening panel. We summarize the assumptions and findings for 2 models (MCAD and CF) and discuss them in relation to findings in the peer-reviewed literature.

FINDINGS

The MCAD model projected a benefit-cost ratio of 3.4 to 1 based on assumptions of a 20.0 percentage point reduction in infant mortality and a 13.9 percentage point reduction in serious developmental disability. The CF model projected a benefit-cost ratio of 4.0-5.4 to 1 for a discount rate of 3%-4% and a plausible range of 1-2 percentage point reductions in deaths up to age 10 years.

CONCLUSIONS

The Washington State cost-benefit models of newborn screening were broadly consistent with peer-reviewed literature, and their findings of net benefit appear to be robust to uncertainty in parameters. Public health newborn screening programs can develop their own capacity to project expected costs and benefits of expansion of newborn screening panels, although it would be most efficient if this capacity were shared among programs.

Immunodeficiencies Associated with Abnormal Newborn Screening for T Cell and B Cell Lymphopenia

Newborn screening for SCID has revealed the association of low T cells with a number of unexpected syndromes associated with low T cells, some of which were not appreciated to have this feature. This review will discuss diagnostic approaches and the features of some of the syndromes likely to be encountered following newborn screening for immune deficiencies.

Costs of Hospital Admission on Primary Immunodeficiency Diseases

BACKGROUND

Primary immunodeficiency diseases (PID) are heterogeneous group of inherited disorders mainly characterized by recurrent infections leading to several times hospital admissions. The economic impact of PID is a challenging issue; therefore, this study was designed to determine the medical costs of hospitalizations in this group of patients as an indicator of the direct cost of these diseases.

METHODS

One hundred and ten children with PID hospitalized in the Children's Medical Center Hospital, Tehran, Iran were included in this study during Jan 2011 and Jan 2012. All direct costs during the admission period were calculated, using the hospital information system.

RESULTS

Medical cost was 7.090$ per patient per admission. Among them, about 1.580$ belong to drug consuming during hospitalization. Anti-infective drugs for systemic use were the most cost-consuming group of drugs, followed by alimentary tract and metabolism and blood and blood forming organs agents. Investigation of anti-infective group internally showed that immune sera and immunoglobulin and antiviral agents for systemic use consisting the most important medication for PID patients during hospital admission.

CONCLUSION

Although the results of economic evaluations in a region cannot necessarily be applied to other regions, having an overall estimation of hospital admission costs and types of drugs used during admission could be helpful in health policy system.

Newborn screening for severe combined immunodeficiency using a novel and simplified method to measure T-cell excision circles (TREC)

The prognosis of children with severe combined immunodeficiency (SCID) depends on a presymptomatic diagnosis and early treatment before complications occur. We established and tested a simplified, practical and economic newborn screening method based on the quantification of T-cell receptor excision circles (TRECs) on dried blood spots (DBSs) through qPCR. Our method was validated by the analysis of 11 positive controls, which all showed an absence of TRECs, thus yielding a sensitivity of 100%. Further, we analyzed 6034 anonymized newborns of whom 6031 (99,95%) showed a normal TREC qPCR with a median of 600 estimated TREC copies/1.6mm punch. The test showed a recall-rate of 0.05%. We present a highly sensitive, specific and time- and cost-effective method of TREC quantification, which is suitable for SCID newborn screening. In comparison to established methods, our test requires only 25% of the input material, doesn't require DNA purification and significantly reduces time and cost requirement.

Neonatal screening for severe combined immunodeficiency in Brazil

OBJECTIVE

To apply, in Brazil, the T-cell receptor excision circles (TRECs) quantification technique using real-time polymerase chain reaction in newborn screening for severe combined immunodeficiency and assess the feasibility of implementing it on a large scale in Brazil.

METHODS

8715 newborn blood samples were collected on filter paper and, after DNA elution, TRECs were quantified by real-time polymerase chain reaction. The cutoff value to determine whether a sample was abnormal was determined by ROC curve analysis, using SSPS.

RESULTS

The concentration of TRECs in 8,682 samples ranged from 2 to 2,181TRECs/μL of blood, with mean and median of 324 and 259TRECs/μL, respectively. Forty-nine (0.56%) samples were below the cutoff (30TRECs/μL) and were reanalyzed. Four (0.05%) samples had abnormal results (between 16 and 29TRECs/μL). Samples from patients previously identified as having severe combined immunodeficiency or DiGeorge syndrome were used to validate the assay and all of them showed TRECs below the cutoff. Preterm infants had lower levels of TRECs than full-term neonates. The ROC curve showed a cutoff of 26TRECs/μL, with 100% sensitivity for detecting severe combined immunodeficiency. Using this value, retest and referral rates were 0.43% (37 samples) and 0.03% (3 samples), respectively.

CONCLUSION

The technique is reliable and can be applied on a large scale after the training of technical teams throughout Brazil.

Advances in neonatal screening for primary immune deficiencies

The congenital disorders of immune competence are known as primary immunodeficiencies (PID) and are mainly characterized by a pathological susceptibility to infection. These infections are mostly of time repetitive and drug resistant in nature. The number of infected infants has reached over 200 and is on the increase. Additionally, clinical severity of the disease has been confirmed to be extensive. The increasing number of these severe PIDs is due to the lack of specific as well as efficient management avenues. New assays and concepts for newborn screening of severe primary immune deficiencies are being explored and the present review focused on these new upcoming strategies for improved screening of neonates.

Cost-Effectiveness/Cost-Benefit Analysis of Newborn Screening for Severe Combined Immune Deficiency in Washington State

OBJECTIVE

To evaluate the expected cost-effectiveness and net benefit of the recent implementation of newborn screening (NBS) for severe combined immunodeficiency (SCID) in Washington State.

STUDY DESIGN

We constructed a decision analysis model to estimate the costs and benefits of NBS in an annual birth cohort of 86 600 infants based on projections of avoided infant deaths. Point estimates and ranges for input variables, including the birth prevalence of SCID, proportion detected asymptomatically without screening through family history, screening test characteristics, survival rates, and costs of screening, diagnosis, and treatment were derived from published estimates, expert opinion, and the Washington NBS program. We estimated treatment costs stratified by age of identification and SCID type (with or without adenosine deaminase deficiency). Economic benefit was estimated using values of $4.2 and $9.0 million per death averted. We performed sensitivity analyses to evaluate the influence of key variables on the incremental cost-effectiveness ratio (ICER) of net direct cost per life-year saved.

RESULTS

Our model predicts an additional 1.19 newborn infants with SCID detected preclinically through screening, in addition to those who would have been detected early through family history, and 0.40 deaths averted annually. Our base-case model suggests an ICER of $35 311 per life-year saved, and a benefit-cost ratio of either 5.31 or 2.71. Sensitivity analyses found ICER values <$100 000 and positive net benefit for plausible assumptions on all variables.

CONCLUSIONS

Our model suggests that NBS for SCID in Washington is likely to be cost-effective and to show positive net economic benefit.

Expanded newborn screening by mass spectrometry: New tests, future perspectives

Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.

The Role of Information Provision in Economic Evaluations of Newborn Bloodspot Screening: A Systematic Review

BACKGROUND

The extent to which economic evaluations have included the healthcare resource and outcome-related implications of information provision in national newborn bloodspot screening programmes (NBSPs) is not currently known.

OBJECTIVES

To identify if, and how, information provision has been incorporated into published economic evaluations of NBSPs.

METHODS

A systematic review of economic evaluations of NBSPs (up to November 2014) was conducted. Three electronic databases were searched (Ovid: Medline, Embase, CINAHL) using an electronic search strategy combining a published economic search filter with terms related to national NBSPs and screening-related technologies. These electronic searches were supplemented by searching the NHS Economic Evaluations Database (NHS EED) and hand-searching identified study reference lists. The results were tabulated and summarised as part of a narrative synthesis.

RESULTS

A total of 27 economic evaluations [screening-related technologies (n = 11) and NBSPs (n = 16)] were identified. The majority of economic evaluations did not quantify the impact of information provision in terms of healthcare costs or outcomes. Five studies did include an estimate of the time cost associated with information provision. Four studies included a value to reflect the disutility associated with parental anxiety caused by false-positive results, which was used as a proxy for the impact of imperfect information.

CONCLUSION

A limited evidence base currently quantifies the impact of information provision on the healthcare costs and impact on the users of NBSPs; the parents of newborns. We suggest that economic evaluations of expanded NBSPs need to take account of information provision otherwise the impact on healthcare costs and the outcomes for newborns and their parents may be underestimated.

MALDI-TOF-MS Assay to Detect the Hemizygous 22q11.2 Deletion in DNA from Dried Blood Spots

BACKGROUND

A hemizygous deletion of 1.5-3 Mb in 22q11.2 causes a distinct clinical syndrome with variable congenital defects. Current diagnostic methods use fluorescent in situ hybridization (FISH) or comparative genomic hybridization by microarray to detect the deletion. Neither method is suitable for newborn screening (NBS), since they cannot be performed on dried blood spots (DBS). We developed a MALDI-TOF-MS assay that uses DBS to measure the hemizygous deletion of UFD1L, located within the 22q11.2 region.

METHODS

We used DBS from 54 affected patients, previously tested by FISH or microarray, and 100 cord blood samples to evaluate the performance of the MALDI-TOF-MS assay. With a single primer pair, a 97-base oligonucleotide within UFD1L was amplified, as was a sequence on chromosome 18 that differs by 2 nucleotides. A multiplexed, single-base extension reaction created allele-specific products for MALDI-TOF-MS detection. The products were spotted onto a silicon chip, and the height of the spectral peaks identified the relative amounts of target and reference gene.

RESULTS

The median ratio of the spectral peak for each UFD1L target:reference base was 0.96 and 0.99 for controls, compared with 0.35 and 0.53 for 22q11 deletion syndrome patients. There was 100% concordance between FISH/microarray and MALDI-TOF-MS in all patients with 22q11.2 deletion syndrome.

CONCLUSIONS

This method can be reliably performed with DBS and is suitable for high sample throughput. This assay may be considered for use in population-based NBS for 22q11.2 deletion.

Primary Immunodeficiency Diseases in Saudi Arabia: a Tertiary Care Hospital Experience over a Period of Three Years (2010-2013)

PURPOSE

Primary immunodeficiencies (PID) are a group of heterogeneous diseases. Epidemiological studies from databases worldwide show geographical variation. In this study the objective is to determine the spectrum of PID in Saudi Arabia by analyzing the database in a referral tertiary hospital.

METHODS

This is a prospective data collection by interviews and medical chart review for all PID patients followed at the King Faisal Specialist Hospital & Research Center (KFSH&RC) from May 2010 to April 2013.

RESULTS

A total of 502 patients presented (53 % male and 47 % female). Combined immunodeficiencies were the most common (59.7 %), followed by predominantly antibody deficiencies (12.3 %), congenital defects of phagocyte (9.4 %), combined immunodeficiencies with associated or syndromic features (6.2 %), disease of immune dysregulation (6 %), complement deficiencies (5.8), and defects in innate immunity (0.6 %). The most common combined immunodeficiencies phenotype was T-B-SCID (17 %). The patients' ages ranged from less than 1 year old to 78 years, and 394 patients (78.2 %) are in the paediatrics age group (<14 years). The overall mean age of symptoms onset was 17 months and the overall mean delay in diagnosis was 21.6 months. Recurrent infections were the most common occurring clinical presentation (66 %), followed by family history (26 %). Consanguinity was found in 75 % of the patients. A total of 308 (61 %) patients had undergone stem cell transplantation (SCT).

CONCLUSION

The study revealed that combined immunodeficiencies are not uncommon and are the most frequent occurring diagnosis in our patient population. This study is a prerequisite to establish a national registry of primary immunodeficiency in Saudi Arabia.

Practice parameter for the diagnosis and management of primary immunodeficiency

The American Academy of Allergy, Asthma & Immunology (AAAAI) and the American College of Allergy, Asthma & Immunology (ACAAI) have jointly accepted responsibility for establishing the "Practice parameter for the diagnosis and management of primary immunodeficiency." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma & Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion.