Newborn screening for severe combined immunodeficiency in 11 screening programs in the United States.

IMPORTANCE: Newborn screening for severe combined immunodeficiency (SCID) using assays to detect T-cell receptor excision circles (TRECs) began in Wisconsin in 2008, and SCID was added to the national recommended uniform panel for newborn screened disorders in 2010. Currently 23 states, the District of Columbia, and the Navajo Nation conduct population-wide newborn screening for SCID. The incidence of SCID is estimated at 1 in 100,000 births. OBJECTIVES: To present data from a spectrum of SCID newborn screening programs, establish population-based incidence for SCID and other conditions with T-cell lymphopenia, and document early institution of effective treatments. DESIGN: Epidemiological and retrospective observational study. SETTING: Representatives in states conducting SCID newborn screening were invited to submit their SCID screening algorithms, test performance data, and deidentified clinical and laboratory information regarding infants screened and cases with nonnormal results. Infants born from the start of each participating program from January 2008 through the most recent evaluable date prior to July 2013 were included. Representatives from 10 states plus the Navajo Area Indian Health Service contributed data from 3,030,083 newborns screened with a TREC test. MAIN OUTCOMES AND MEASURES: Infants with SCID and other diagnoses of T-cell lymphopenia were classified. Incidence and, where possible, etiologies were determined. Interventions and survival were tracked. RESULTS: Screening detected 52 cases of typical SCID, leaky SCID, and Omenn syndrome, affecting 1 in 58,000 infants (95% CI, 1/46,000-1/80,000). Survival of SCID-affected infants through their diagnosis and immune reconstitution was 87% (45/52), 92% (45/49) for infants who received transplantation, enzyme replacement, and/or gene therapy. Additional interventions for SCID and non-SCID T-cell lymphopenia included immunoglobulin infusions, preventive antibiotics, and avoidance of live vaccines. Variations in definitions and follow-up practices influenced the rates of detection of non-SCID T-cell lymphopenia. CONCLUSIONS AND RELEVANCE: Newborn screening in 11 programs in the United States identified SCID in 1 in 58,000 infants, with high survival. The usefulness of detection of non-SCID T-cell lymphopenias by the same screening remains to be determined.

Newborn screening for severe combined immunodeficiency; the Wisconsin experience (2008-2011).

Severe combined immunodeficiency is a life-threatening primary immune deficiency characterized by low numbers of naïve T cells. Early diagnosis and treatment of this disease decreases mortality. In 2008, Wisconsin began newborn screening of infants for severe combined immunodeficiency and other forms of T-cell lymphopenia by the T-cell receptor excision circle assay. In total, 207,696 infants were screened. Seventy-two infants had an abnormal assay. T-cell numbers were normal in 38 infants, abnormal in 33 infants, and not performed in one infant, giving a positive predictive value for T-cell lymphopenia of any cause of 45.83% and a specificity of 99.98%. Five infants with severe combined immunodeficiency/severe T-cell lymphopenia requiring hematopoietic stem cell transplantation or other therapy were detected. In summary, the T-cell receptor excision circle assay is a sensitive and specific test to identify infants with severe combined immunodeficiency and severe T-cell lymphopenia that leads to life-saving therapies such as hematopoietic stem cell transplantation prior to the acquisition of severe infections.

Cause of death in neonates with inconclusive or abnormal T-cell receptor excision circle assays on newborn screening.

INTRODUCTION: During the first 2 years of newborn screening (NBS) for severe combined immunodeficiency (SCID), 39 infants with an abnormal or inconclusive newborn screening test for SCID died prior to assessment of immune function. We investigated if SCID or primary T-cell lymphopenia likely contributed to the death of these neonates. METHODS: This study is a detailed retrospective chart review. RESULTS: Medical records were available in all 39 infants. Three neonates were full-term infants whose deaths were due to congenital anomalies. Thirty-three infants were born <33 weeks estimated gestational age, and the majority of these infants died from complications of prematurity. Six infants died from sepsis: two due to maternal chorioamnionitis, two due to necrotizing enterocolitis, one due to early onset group B strep sepsis, and one from a likely nosocomial infection. CONCLUSIONS: There was no evidence that SCID contributed to the cause of death in neonates with an abnormal of inconclusive NBS test for SCID.

Leadership principles for developing a statewide public health and clinical laboratory system.

In 1999, the Centers for Disease Control and Prevention (CDC), the Association of Public Health Laboratories (APHL), and the Federal Bureau of Investigation established the national Laboratory Response Network (LRN) for bioterrorism readiness. A more broad application of the LRN is the National Laboratory System (NLS), an effort to promote the 10 Essential Public Health Services and the Core Functions and Capabilities of State Public Health Laboratories (hereafter, Core Functions). State public health laboratories (PHLs) are responsible for leading the development of both the LRN and the NLS in their jurisdictions. Based on the experience of creating a laboratory network in Wisconsin, leadership principles are provided for developing and strengthening statewide laboratory networks of PHLs and clinical laboratories, which can also include point-of-care testing sites. Each state PHL, in the context of these Core Functions and leadership principles, sets its priorities, budgets, and strategic plans. For a limited investment of personnel and funds that will yield a large benefit to public health, a robust state laboratory system can be established.

Implementing routine testing for severe combined immunodeficiency within Wisconsin's newborn screening program.

Severe combined immunodeficiency (SCID) is the result of genetic defects that impair normal T-cell development. SCID babies typically appear normal at birth, but acquire multiple life-threatening infections within a few months. Early diagnosis and treatment with a bone-marrow transplant markedly improves long-term outcomes. On January 1, 2008, the newborn screening (NBS) program in Wisconsin became the first in the world to routinely test all newborns for SCID. A realtime quantitative polymerase chain reaction assay measures T-cell receptor excision circles (TRECs), which are formed during the maturation of normal T-cells. A lack or very low number of TRECs is consistent with T-cell lymphopenia. The development and validation of the TREC assay and the results of the first year of screening have been published. This article describes the process used to add SCID to the NBS panel, the establishment of follow-up capacity, and the integration of SCID screening into routine NBS workflows. The development of this expanded NBS program is described so that other states might benefit from the processes used in Wisconsin.

Development of a routine newborn screening protocol for severe combined immunodeficiency.

BACKGROUND: Severe combined immunodeficiency (SCID) is characterized by the absence of functional T cells and B cells. Without early diagnosis and treatment, infants with SCID die from severe infections within the first year of life. OBJECTIVE: To determined the feasibility of detecting SCID in newborns by quantitating T-cell receptor excision circles (TRECs) from dried blood spots (DBSs) on newborn screening (NBS) cards. METHODS: DNA was extracted from DBSs on deidentified NBS cards, and real-time quantitative PCR (RT-qPCR) was used to determine the number of TRECs. Positive controls consisted of DBS from a 1-week-old T(-)B(-)NK(+) patient with SCID and whole blood specimens selectively depleted of naive T cells. RESULTS: The mean and median numbers of TRECs from 5766 deidentified DBSs were 827 and 708, respectively, per 3.2-mm punch ( approximately 3 muL whole blood). Ten samples failed to amplify TRECs on initial analysis; all but 1 demonstrated normal TRECs and beta-actin amplification on retesting. No TRECs were detected in either the SCID or naive T-cell-depleted samples, despite the presence of normal levels of beta-actin. CONCLUSIONS: The use of RT-qPCR to quantitate TRECs from DNA extracted from newborn DBSs is a highly sensitive and specific screening test for SCID. This assay is currently being used in Wisconsin for routine screening infants for SCID.

A 15 Year Evaluation of West Nile Virus in Wisconsin: Effects on Wildlife and Human Health.

West Nile virus (WNV) is the most important and widespread mosquito-borne virus in the United States (U.S.). WNV has the ability to spread rapidly and effectively, infecting more than 320 bird and mammalian species. An examination of environmental conditions and the health of keystone species may help predict the susceptibility of various habitats to WNV and reveal key risk factors, annual trends, and vulnerable regions. Since 2002, WNV outbreaks in Wisconsin varied by species, place, and time, significantly affected by unique climatic, environmental, and geographical factors. During a 15 year period, WNV was detected in 71 of 72 counties, resulting in 239 human and 1397 wildlife cases. Controlling for population and sampling efforts in Wisconsin, rates of WNV are highest in the western and northwestern rural regions of the state. WNV incidence rates were highest in counties with low human population densities, predominantly wetland, and at elevations greater than 1000 feet. Resources for surveillance, prevention, and detection of WNV were lowest in rural counties, likely resulting in underestimation of cases. Overall, increasing mean temperature and decreasing precipitation showed positive influence on WNV transmission in Wisconsin. This study incorporates the first statewide assessment of WNV in Wisconsin.

Statewide newborn screening for severe T-cell lymphopenia.

CONTEXT: A newborn blood screening (NBS) test that could identify infants with a profound deficiency of T cells may result in a reduction in mortality. OBJECTIVE: To determine if quantitating T-cell receptor excision circles (TRECs) using real-time quantitative polymerase chain reaction on DNA extracted from dried blood spots on NBS cards can detect infants with T-cell lymphopenia in a statewide program. DESIGN, SETTING, AND PARTICIPANTS: Between January 1 and December 31, 2008, the Wisconsin State Laboratory of Hygiene screened all infants born in Wisconsin for T-cell lymphopenia by quantitating the number of TRECs contained in a 3.2-mm punch (approximately 3 microL of whole blood) of the NBS card. Flow cytometry to enumerate the number of T cells was performed on full-term infants and preterm infants when they reached the equivalent of at least 37 weeks' gestation with TREC values of less than 25/microL. Infants with T-cell lymphopenia were evaluated by a clinical immunologist. MAIN OUTCOME MEASURES: The number of infants with TREC values of less than 25/microL with T-cell lymphopenia confirmed by flow cytometry. RESULTS: Exactly 71,000 infants were screened by the TREC assay. Seventeen infants aged at least 37 weeks' gestation had at least 1 abnormal TREC assay (TREC values < 25/microL), 11 of whom had samples analyzed by flow cytometry to enumerate T cells. Eight infants demonstrated T-cell lymphopenia. The causes of the T-cell lymphopenia included DiGeorge syndrome (n = 2), idiopathic T-cell lymphopenia (n = 2), extravascular extravasation of lymphocytes (n = 3), and a Rac2 mutation (n = 1). The infant with the Rac2 mutation underwent successful cord blood transplantation. CONCLUSION: In a statewide screening program, use of the TREC assay performed on NBS cards was able to identify infants with T-cell lymphopenia.

The laboratory efficiencies initiative: partnership for building a sustainable national public health laboratory system.

Beginning in early 2011, the Centers for Disease Control and Prevention and the Association of Public Health Laboratories launched the Laboratory Efficiencies Initiative (LEI) to help public health laboratories (PHLs) and the nation's entire PHL system achieve and maintain sustainability to continue to conduct vital services in the face of unprecedented financial and other pressures. The LEI focuses on stimulating substantial gains in laboratories' operating efficiency and cost efficiency through the adoption of proven and promising management practices. In its first year, the LEI generated a strategic plan and a number of resources that PHL directors can use toward achieving LEI goals. Additionally, the first year saw the formation of a dynamic community of practitioners committed to implementing the LEI strategic plan in coordination with state and local public health executives, program officials, foundations, and other key partners.