- Email: [email protected]
Laboratory technology for population-based screening for severe combined immunodeficiency in neonates: The winner is T-cell receptor excision circles
Continuing Medical Education examination
Laboratory technology for population-based screening for severe combined immunodeficiency in neonates: The winner is T-cell receptor excision circles Instructions for category 1 Continuing Medical Education credit The American Academy of Allergy, Asthma & Immunology is accredited as a provider of Continuing Medical Education (CME) by the Accreditation Council for Continuing Medical Education. Test ID no.: mai00240 Contact hours: 1.0 Expiration date: February 28, 2014 Category 1 credit can be earned by reading the text material and taking this CME examination online. For complete instructions, visit the Journal’s Web site at www.jacionline.org.
The Editors thank the Baylor College of Medicine Allergy/Immunology training program for developing this CME examination. The individuals who contributed to its preparation were Sarah Nicholas, MD, Sanny Chan, MD, PhD, Serge De Golovine, MD, Evelyn Leechawengwongs, MD, Zahida Maskatia, MD, Shivani Rasalingam, MD, Neha Seth, MD, Madhu Narra, MD, MS, and Lenora Noroski, MD, MPH, under the direction of William T. Shearer, MD, PhD.
Learning objectives: ‘‘Laboratory technology for population-based screening for severe combined immunodeficiency in neonates: The winner is T-cell receptor excision circles’’ 1. 2. 3. 4. 5.
To To To To To
explain the importance of newborn screening for severe combined immunodeficiency (SCID). describe the criteria for newborn screening and how T-cell receptor excision circle (TREC) analysis fits these criteria. identify normal, abnormal, and invalid TREC screening results and which disease states would contribute to each. describe TREC analysis and alternate screening methods. define SCID and the relevant cutoffs for normal T-cell populations.
CME items Question 1. Early screening for SCID is important because — A. SCID is a fatal disease that is untreatable. B. affected subjects are usually recognizable on clinical examination. C. early treatment increases the likelihood of survival. D. the incidence is high in the general population. Question 2. Which of the following statements is true regarding the treatment of SCID? A. Treatment requires hematopoietic stem cell transplantation. B. Treatment outcomes are better in healthy, infection-free children. C. Treatment is not necessary because it resolves with age. D. Patients can be treated at any time with the same outcomes.
J ALLERGY CLIN IMMUNOL
Question 3. Newborn screening for SCID — A. focuses on suspected cases and requires liquid blood samples. B. is ineffective because subjects are often lost to follow-up. C. is prohibitively expensive. D. can be done using dried blood spots. Question 4. Which of the following is the mean absolute lymphocyte count (ALC) of term newborns? A. 1000/mL B. 3000/mL C. 5000/mL D. 7000/mL
March 2012
617
618 PUCK
Question 5. Which of the following diseases would MOST likely be identified if the ALC alone was used for SCID newborn screening? A. MHC class II deficiency B. adenosine deaminase–deficient SCID C. Omenn syndrome D. IL-7 receptor (IL-7R)–deficient SCID Question 6. Which of the following statements regarding gene resequencing in patients with SCID is true? A. Resequencing arrays have a high false-positive rate. B. It is a cost-effective screening tool. C. Some diagnoses would be missed if this method is used for screening. D. There are fewer than 10 known SCID-causing genes. Question 7. Which of the following statements about the TREC test for newborn screening is correct? A. It is a reliable biomarker of naive T and B cells. B. It gives an accurate measurement of peripheral ALC. C. It can be used as an indicator of new thymic emigrant T cells. D. It indicates the presence of both immature and mature T cells.
J ALLERGY CLIN IMMUNOL MARCH 2012
Question 8. Which of the following patient populations’ blood samples have the highest number of TRECs? A. infants B. adolescents C. adults D. patients with Omenn syndrome Question 9. DNA amplification failures were seen MOST commonly from infants — A. in neonatal intensive care units. B. weighing less than 1500 g at birth. C. with samples obtained from an intravenous line. D. with low T-cell counts. Question 10. Which of the following immunodeficiencies will be missed by newborn TREC analysis? A. z chain–associated protein (70 kDa [Zap70]) deficiency, MHC class II deficiency, and nuclear factor kB essential modulator (NEMO) deficiency B. Zap70 deficiency, IL-7R defects, and NEMO deficiency C. complete DiGeorge syndrome, MHC class II deficiency, and RAC2 deficiency D. IL-7R defects, MHC class II deficiency, and Janus kinase 3 deficiency
Laboratory technology for population-based screening for severe combined immunodeficiency in neonates: The winner is T-cell receptor excision circles Instructions for category 1 Continuing Medical Education credit The American Academy of Allergy, Asthma & Immunology is accredited as a provider of Continuing Medical Education (CME) by the Accreditation Council for Continuing Medical Education. Test ID no.: mai00240 Contact hours: 1.0 Expiration date: February 28, 2014 Category 1 credit can be earned by reading the text material and taking this CME examination online. For complete instructions, visit the Journal’s Web site at www.jacionline.org.
The Editors thank the Baylor College of Medicine Allergy/Immunology training program for developing this CME examination. The individuals who contributed to its preparation were Sarah Nicholas, MD, Sanny Chan, MD, PhD, Serge De Golovine, MD, Evelyn Leechawengwongs, MD, Zahida Maskatia, MD, Shivani Rasalingam, MD, Neha Seth, MD, Madhu Narra, MD, MS, and Lenora Noroski, MD, MPH, under the direction of William T. Shearer, MD, PhD.
Learning objectives: ‘‘Laboratory technology for population-based screening for severe combined immunodeficiency in neonates: The winner is T-cell receptor excision circles’’ 1. 2. 3. 4. 5.
To To To To To
explain the importance of newborn screening for severe combined immunodeficiency (SCID). describe the criteria for newborn screening and how T-cell receptor excision circle (TREC) analysis fits these criteria. identify normal, abnormal, and invalid TREC screening results and which disease states would contribute to each. describe TREC analysis and alternate screening methods. define SCID and the relevant cutoffs for normal T-cell populations.
CME items Question 1. Early screening for SCID is important because — A. SCID is a fatal disease that is untreatable. B. affected subjects are usually recognizable on clinical examination. C. early treatment increases the likelihood of survival. D. the incidence is high in the general population. Question 2. Which of the following statements is true regarding the treatment of SCID? A. Treatment requires hematopoietic stem cell transplantation. B. Treatment outcomes are better in healthy, infection-free children. C. Treatment is not necessary because it resolves with age. D. Patients can be treated at any time with the same outcomes.
J ALLERGY CLIN IMMUNOL
Question 3. Newborn screening for SCID — A. focuses on suspected cases and requires liquid blood samples. B. is ineffective because subjects are often lost to follow-up. C. is prohibitively expensive. D. can be done using dried blood spots. Question 4. Which of the following is the mean absolute lymphocyte count (ALC) of term newborns? A. 1000/mL B. 3000/mL C. 5000/mL D. 7000/mL
March 2012
617
618 PUCK
Question 5. Which of the following diseases would MOST likely be identified if the ALC alone was used for SCID newborn screening? A. MHC class II deficiency B. adenosine deaminase–deficient SCID C. Omenn syndrome D. IL-7 receptor (IL-7R)–deficient SCID Question 6. Which of the following statements regarding gene resequencing in patients with SCID is true? A. Resequencing arrays have a high false-positive rate. B. It is a cost-effective screening tool. C. Some diagnoses would be missed if this method is used for screening. D. There are fewer than 10 known SCID-causing genes. Question 7. Which of the following statements about the TREC test for newborn screening is correct? A. It is a reliable biomarker of naive T and B cells. B. It gives an accurate measurement of peripheral ALC. C. It can be used as an indicator of new thymic emigrant T cells. D. It indicates the presence of both immature and mature T cells.
J ALLERGY CLIN IMMUNOL MARCH 2012
Question 8. Which of the following patient populations’ blood samples have the highest number of TRECs? A. infants B. adolescents C. adults D. patients with Omenn syndrome Question 9. DNA amplification failures were seen MOST commonly from infants — A. in neonatal intensive care units. B. weighing less than 1500 g at birth. C. with samples obtained from an intravenous line. D. with low T-cell counts. Question 10. Which of the following immunodeficiencies will be missed by newborn TREC analysis? A. z chain–associated protein (70 kDa [Zap70]) deficiency, MHC class II deficiency, and nuclear factor kB essential modulator (NEMO) deficiency B. Zap70 deficiency, IL-7R defects, and NEMO deficiency C. complete DiGeorge syndrome, MHC class II deficiency, and RAC2 deficiency D. IL-7R defects, MHC class II deficiency, and Janus kinase 3 deficiency