Giancarlo la Marca1, Clementina Canessa2, Elisa Giocaliere1, Francesca Romano2, Sabrina Malvagia1, Silvia Funghini1, Maria Moriondo2, Claudia Valleriani2, Francesca Lippi2, Daniela Ombrone1, Maria Luisa Della Bona1, Carsten Speckmann3, Stephan Borte4, Nicholas Brodszki5, Andrew R Gennery6, Katja Weinacht7, Fatih Celmeli8, Julia Pagel9, Maurizio de Martino2, Renzo Guerrini10, Helmut Wittkowski11, Ines Santisteban12, Pawan Bali12, Aydan Ikinciogullari13, Michael Hershfield12, Luigi D Notarangelo14, Massimo Resti2, Chiara Azzari15. 1. Newborn Screening, Biochemistry and Pharmacology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Florence, Italy; Department of Neurosciences, Psychology, Pharmacology and Child Health, University of Florence, Florence, Italy. 2. Meyer Children's University Hospital, Florence, Italy; Department of Health Sciences, University of Florence, Florence, Italy. 3. Zentrum fur Kinderheilkunde und Jugendmedizin, Centrum fuer Chronische, Immundefizienz-Universitaet Freiburg, Freiburg, Germany. 4. Division of Clinical Immunology and Transfusion Medicine, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden; Translational Centre for Regenerative Medicine (TRM), University of Leipzig, Leipzig, Germany. 5. Department of Allergy and Immunology, Children's Hospital Lund, Skane University Hospital, Lund, Sweden. 6. Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom. 7. Division of Hematology and Oncology, Children's Hospital, Boston, Mass; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Mass. 8. Antalya Education and Research Hospital, Pediatric Immunology and Allergy, Antalya, Turkey. 9. Pädiatrische Hämatologie und Onkologie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany; Department of General Pediatrics, University Children's Hospital Muenster, Münster, Germany. 10. Newborn Screening, Biochemistry and Pharmacology Laboratory, Paediatric Neurology Unit and Laboratories, Neuroscience Department, Meyer Children's Hospital, Florence, Italy. 11. Pediatric Rheumatology and Immunology, University Children's Hospital Muenster, Münster, Germany. 12. Department of Medicine, Duke University, Medical Center, Durham, NC. 13. Department of Pediatric Immunology and Allergy, Ankara University Medical School, Ankara, Turkey. 14. Division of Immunology, Children's Hospital, Boston, Mass. 15. Meyer Children's University Hospital, Florence, Italy; Department of Health Sciences, University of Florence, Florence, Italy. Electronic address: chiara.azzari@unifi.it.
Abstract
BACKGROUND: Purine nucleoside phosphorylase (PNP) deficiency is a rare form of autosomal recessive combined primary immunodeficiency caused by a enzyme defect leading to the accumulation of inosine, 2'-deoxy-inosine (dIno), guanosine, and 2'-deoxy-guanosine (dGuo) in all cells, especially lymphocytes. Treatments are available and curative for PNP deficiency, but their efficacy depends on the early approach. PNP-combined immunodeficiency complies with the criteria for inclusion in a newborn screening program. OBJECTIVE: This study evaluate whether mass spectrometry can identify metabolite abnormalities in dried blood spots (DBSs) from affected patients, with the final goal of individuating the disease at birth during routine newborn screening. METHODS: DBS samples from 9 patients with genetically confirmed PNP-combined immunodeficiency, 10,000 DBS samples from healthy newborns, and 240 DBSs from healthy donors of different age ranges were examined. Inosine, dIno, guanosine, and dGuo were tested by using tandem mass spectrometry (TMS). T-cell receptor excision circle (TREC) and kappa-deleting recombination excision circle (KREC) levels were evaluated by using quantitative RT-PCR only for the 2 patients (patients 8 and 9) whose neonatal DBSs were available. RESULTS: Mean levels of guanosine, inosine, dGuo, and dIno were 4.4, 133.3, 3.6, and 3.8 μmol/L, respectively, in affected patients. No indeterminate or false-positive results were found. In patient 8 TREC levels were borderline and KREC levels were abnormal; in patient 9 TRECs were undetectable, whereas KREC levels were normal. CONCLUSION: TMS is a valid method for diagnosis of PNP deficiency on DBSs of affected patients at a negligible cost. TMS identifies newborns with PNP deficiency, whereas TREC or KREC measurement alone can fail.
BACKGROUND:Purine nucleoside phosphorylase (PNP) deficiency is a rare form of autosomal recessive combined primary immunodeficiency caused by a enzyme defect leading to the accumulation of inosine, 2'-deoxy-inosine (dIno), guanosine, and 2'-deoxy-guanosine (dGuo) in all cells, especially lymphocytes. Treatments are available and curative for PNP deficiency, but their efficacy depends on the early approach. PNP-combined immunodeficiency complies with the criteria for inclusion in a newborn screening program. OBJECTIVE: This study evaluate whether mass spectrometry can identify metabolite abnormalities in dried blood spots (DBSs) from affected patients, with the final goal of individuating the disease at birth during routine newborn screening. METHODS: DBS samples from 9 patients with genetically confirmed PNP-combined immunodeficiency, 10,000 DBS samples from healthy newborns, and 240 DBSs from healthy donors of different age ranges were examined. Inosine, dIno, guanosine, and dGuo were tested by using tandem mass spectrometry (TMS). T-cell receptor excision circle (TREC) and kappa-deleting recombination excision circle (KREC) levels were evaluated by using quantitative RT-PCR only for the 2 patients (patients 8 and 9) whose neonatal DBSs were available. RESULTS: Mean levels of guanosine, inosine, dGuo, and dIno were 4.4, 133.3, 3.6, and 3.8 μmol/L, respectively, in affected patients. No indeterminate or false-positive results were found. In patient 8 TREC levels were borderline and KREC levels were abnormal; in patient 9 TRECs were undetectable, whereas KREC levels were normal. CONCLUSION: TMS is a valid method for diagnosis of PNP deficiency on DBSs of affected patients at a negligible cost. TMS identifies newborns with PNP deficiency, whereas TREC or KREC measurement alone can fail.
Authors: Nicholas Brodszki; Maria Svensson; André B P van Kuilenburg; Judith Meijer; Lida Zoetekouw; Lennart Truedsson; Jacek Toporski Journal: JIMD Rep Date: 2015-05-13
Authors: Maartje Blom; Rolf H Zetterström; Asbjørg Stray-Pedersen; Kimberly Gilmour; Andrew R Gennery; Jennifer M Puck; Mirjam van der Burg Journal: J Allergy Clin Immunol Date: 2021-09-16 Impact factor: 14.290
Authors: Anna Eichinger; Horst von Bernuth; Michael H Albert; Fabian Hauck; Cinzia Dedieu; Sebastian A Schroeder; Giancarlo la Marca Journal: J Clin Immunol Date: 2021-02-27 Impact factor: 8.317