Cheng-Lung Ku1,2,3, Luan-Yin Chang4, Tzou-Yien Lin5,6, Chen-Yen Kuo7,8,9, Hye-Kyung Lim10,11,12, Shao-Hsuan Hsia13, Jainn-Jim Lin13, Chia-Chi Lo7, Jing-Ya Ding7, Rei-Lin Kuo14,15, Jean-Laurent Casanova10,11,12,16,17, Shen-Ying Zhang10,11,12. 1. Laboratory of Human Immunology and Infectious Diseases, Graduate Institute of Clinical Medical Sciences, Chang Gung University, No. 259 Wen-Hwa 1st Road, Kwei-Shan 333, Taoyuan, Taiwan. clku@cgu.edu.tw. 2. Center for Molecular and Clinical Immunology, Chang Gung University, Taoyuan, Taiwan. clku@cgu.edu.tw. 3. Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan. clku@cgu.edu.tw. 4. Department of Pediatrics, National Taiwan University Hospital, 7, Chung-Shan South Road, Taipei, 100, Taiwan. lychang@ntu.edu.tw. 5. Division of Infectious Diseases, Department of Pediatrics, Linkou Chang Gung Memorial Hospital, No. 5, Fu-Shin St, Kwei-Shan 333, Taoyuan, Taiwan. pidlin@cgmh.org.tw. 6. College of Medicine, Chang Gung University, Taoyuan, Taiwan. pidlin@cgmh.org.tw. 7. Laboratory of Human Immunology and Infectious Diseases, Graduate Institute of Clinical Medical Sciences, Chang Gung University, No. 259 Wen-Hwa 1st Road, Kwei-Shan 333, Taoyuan, Taiwan. 8. Division of Infectious Diseases, Department of Pediatrics, Linkou Chang Gung Memorial Hospital, No. 5, Fu-Shin St, Kwei-Shan 333, Taoyuan, Taiwan. 9. College of Medicine, Chang Gung University, Taoyuan, Taiwan. 10. St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY, USA. 11. Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Necker Hospital for Sick Children, Paris, France. 12. Imagine Institute, Paris Descartes University, Paris, France. 13. Division of Pediatric Critical Care Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan. 14. Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan. 15. Research Center for Emerging Viral Infections, Chang Gung University, Taoyuan, Taiwan. 16. Howard Hughes Medical Institute, New York, NY, USA. 17. Pediatric Immuno-Hematology Unit, Necker Hospital, AP-HP, Necker Hospital for Sick Children, Paris, France.
Abstract
PURPOSE: Enterovirus A71 (EV71) causes a broad spectrum of childhood diseases, ranging from asymptomatic infection or self-limited hand-foot-and-mouth disease (HFMD) to life-threatening encephalitis. The molecular mechanisms underlying these different clinical presentations remain unknown. We hypothesized that EV71 encephalitis in children might reflect an intrinsic host single-gene defect of antiviral immunity. We searched for mutations in the toll-like receptor 3 (TLR3) gene. Such mutations have already been identified in children with herpes simplex virus encephalitis (HSE). METHODS: We sequenced TLR3 and assessed the impact of the mutations identified. We tested dermal fibroblasts from a patient with EV71 encephalitis and a TLR3 mutation and other patients with known genetic defects of TLR3 or related genes, assessing the response of these cells to TLR3 agonist poly(I:C) stimulation and EV71 infection. RESULTS: Three children with EV71 encephalitis were heterozygous for rare mutations-TLR3 W769X, E211K, and R867Q-all of which were shown to affect TLR3 function. Furthermore, fibroblasts from the patient heterozygous for the W769X mutation displayed an impaired, but not abolished, response to poly(I:C). We found that TLR3-deficient and TLR3-heterozygous W769X fibroblasts were highly susceptible to EV71 infection. CONCLUSIONS: Autosomal dominant TLR3 deficiency may underlie severe EV71 infection with encephalitis. Human TLR3 immunity is essential to protect the central nervous system against HSV-1 and EV71. Children with severe EV71 infections, such as encephalitis in particular, should be tested for inborn errors of TLR3 immunity.
PURPOSE: Enterovirus A71 (EV71) causes a broad spectrum of childhood diseases, ranging from asymptomatic infection or self-limited hand-foot-and-mouth disease (HFMD) to life-threatening encephalitis. The molecular mechanisms underlying these different clinical presentations remain unknown. We hypothesized that EV71 encephalitis in children might reflect an intrinsic host single-gene defect of antiviral immunity. We searched for mutations in the toll-like receptor 3 (TLR3) gene. Such mutations have already been identified in children with herpes simplex virus encephalitis (HSE). METHODS: We sequenced TLR3 and assessed the impact of the mutations identified. We tested dermal fibroblasts from a patient with EV71 encephalitis and a TLR3 mutation and other patients with known genetic defects of TLR3 or related genes, assessing the response of these cells to TLR3 agonist poly(I:C) stimulation and EV71 infection. RESULTS: Three children with EV71 encephalitis were heterozygous for rare mutations-TLR3 W769X, E211K, and R867Q-all of which were shown to affect TLR3 function. Furthermore, fibroblasts from the patient heterozygous for the W769X mutation displayed an impaired, but not abolished, response to poly(I:C). We found that TLR3-deficient and TLR3-heterozygous W769X fibroblasts were highly susceptible to EV71 infection. CONCLUSIONS: Autosomal dominant TLR3 deficiency may underlie severe EV71 infection with encephalitis. Human TLR3 immunity is essential to protect the central nervous system against HSV-1 and EV71. Children with severe EV71 infections, such as encephalitis in particular, should be tested for inborn errors of TLR3 immunity.