Figures
Abstract
Purpose
Nephrotic syndrome is a common chronic illness encountered during childhood. Infections have been identified as a cause of nephrotic syndrome. The aim of this study was to evaluate the association between enteroviral infection and nephrotic syndrome.
Methods
A nationwide retrospective cohort study was conducted by analyzing data from the National Health Insurance Research Database in Taiwan. Children aged <18 years with enteroviral infection were enrolled. Non-enterovirus-infected children were randomly selected as the comparison cohort. The primary endpoint was the occurrence of nephrotic syndrome.
Methods
This study included 280,087 enterovirus-infected children and 280,085 non-enterovirus-infected children. The mean age of the enterovirus-infected children was 2.38 years, and 53.7% of these children were boys. The overall incidence densities of nephrotic syndrome for enterovirus- and non-enterovirus-infected children were 2.65 and 2.21 per 10,000 person-years, respectively. The enterovirus-infected cohort had a higher cumulative incidence of nephrotic syndrome than did the non-enterovirus-infected cohort (log-rank test, p = 0.01). Multivariable analyses revealed that children with enteroviral infection were significantly associated with an increased risk of nephrotic syndrome compared with those without enteroviral infection (adjusted hazard ratio, 1.20; 95% confidence interval, 1.04–1.39; p = 0.01), particularly in children infected with coxsackievirus. Subgroup analyses revealed that enterovirus-infected girls, children of blue-collar workers, and children without allergies had a higher risk of nephrotic syndrome than did children in the non-enterovirus-infected cohort.
Citation: Lin J-N, Lin C-L, Yang C-H, Lin M-C, Lai C-H, Lin H-H, et al. (2016) Risk of Nephrotic Syndrome following Enteroviral Infection in Children: A Nationwide Retrospective Cohort Study. PLoS ONE 11(8): e0161004. https://doi.org/10.1371/journal.pone.0161004
Editor: Dong-Yan Jin, University of Hong Kong, HONG KONG
Received: April 26, 2016; Accepted: June 15, 2016; Published: August 10, 2016
Copyright: © 2016 Lin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All data and related metadata were deposited in an appropriate public repository. The data on the study population that were obtained from the NHIRD (http://nhird.nhri.org.tw/en/index.html) are maintained in the NHIRD (http://nhird.nhri.org.tw/). The NHRI is a nonprofit foundation established by the government. Only citizens of the Republic of China who fulfill the requirements of conducting research projects are eligible to apply for the NHIRD. The use of NHIRD is limited to research purposes only. Applicants must follow the Computer-Processed Personal Data Protection Law (http://www.winklerpartners.com/?p=987) and related regulations of National Health Insurance Administration and NHRI, and an agreement must be signed by the applicant and his/her supervisor upon application submission. All applications are reviewed for approval of data release.
Funding: This study is supported in part by Taiwan Ministry of Health and Welfare Clinical Trial and Research Center of Excellence (MOHW105-TDU-B-212-133019), China Medical University Hospital, Academia Sinica Taiwan Biobank Stroke Biosignature Project (BM10501010037), NRPB Stroke Clinical Trial Consortium (MOST 104-2325-B-039 -005), Tseng-Lien Lin Foundation, Taichung, Taiwan, Taiwan Brain Disease Foundation, Taipei, Taiwan, and Katsuzo and Kiyo Aoshima Memorial Funds, Japan; and CMU under the Aim for Top University Plan of the Ministry of Education, Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding was received for this study.
Competing interests: The authors have declared that no competing interests exist.
Abbreviations: HIV, human immunodeficiency virus; NHIRD, National Health Insurance Research Database; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; HR, hazard ratio; CI, confidence interval
Introduction
Nephrotic syndrome, characterized by proteinuria, hypoalbuminemia, and generalized edema, is among the most common chronic kidney diseases encountered during childhood [1,2]. It can be idiopathic or provoked by systemic diseases (eg, diabetes mellitus, systemic lupus erythematosus, amyloidosis, and cancers), drugs, and infections [2]. The incidence and prevalence of idiopathic nephrotic syndrome are 1–7 and 16 per 100,000 children, respectively [2,3]. The long-term prognosis of nephrotic syndrome is generally favorable; however, its characteristics and related therapy can massively influence childhood development and quality of life in children. Refractory nephrotic syndrome in some patients may progress to end-stage renal disease [2,4].
Enteroviruses include diverse RNA viruses classified in the Picornaviridae family. More than 90 distinct viral serotypes, including enteroviruses, polioviruses, coxsackieviruses, rhinoviruses, and echoviruses, have been identified [5,6]. Enteroviral infections are common among children worldwide. The Centers for Disease Control and Prevention estimated that approximately 10–15 million infections of non-polio enteroviruses occurred in the United States annually [7]. Enteroviral infections present a wide range of manifestations, such as hand-foot-and-mouth disease, meningitis, encephalitis, conjunctivitis, herpangina, myocarditis, pericarditis, acute flaccid paralysis, and inflammatory muscle disease [5–7].
Several pathogens, including hepatitis B virus, hepatitis C virus, human immunodeficiency virus (HIV), malaria, syphilis, and toxoplasmosis have been known to be associated with nephrotic syndrome [2]. Over the last 50 years, enteroviruses, particularly coxsackieviruses, have been sporadically reported to be causative pathogens of glomerulonephritis and nephrotic syndrome [8–14]. Receptors for coxsackievirus have been identified in the human kidney [15,16]. However, studies on the association between enteroviral infection and renal diseases are limited. According to our review of relevant literature, no epidemiologic study has investigated the incidence of nephrotic syndrome following enteroviral infection. Therefore, we conducted a nationwide retrospective cohort study to determine the subsequent risk of nephrotic syndrome in children infected with enteroviruses by analyzing data from the National Health Insurance Research Database (NHIRD) of Taiwan.
Materials and Methods
Data sources
The National Health Insurance (NHI) program of Taiwan is a single-payer and obligatory health care program initiated in 1995, covering more than 99% of the 23.75 million residents of Taiwan [17]. The NHIRD contains research data released from the NHI program. In this retrospective cohort study, we used research data from the NHI reimbursement claims. To comply with data privacy regulations, personal identities were encrypted and all NHIRD data were analyzed in a deidentified manner. We used a dataset from the NHIRD that consists of a random selection of 50% of all insured children aged <18 years during 2000–2008 in Taiwan. Diagnostic codes of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) were used to identify the diseases.
Ethics statement
The NHIRD encrypts patient personal information to protect privacy and provides researchers with anonymous identification numbers associated with relevant claims information, including sex, date of birth, medical services received, and prescriptions. Therefore, patient consent is not required to access the NHIRD. This study was approved to fulfill the condition for exemption by the Institutional Review Board (IRB) of China Medical University (CMUH104-REC2-115). The IRB also specifically waived the consent requirement.
Study design
The enterovirus-infected cohort included patients aged <18 years with enteroviral infection diagnosed during 2000–2007. The enteroviral infections included enteritis due to enterovirus (ICD-9-CM code 008.67), meningitis due to enterovirus (ICD-9-CM code 047), other enterovirus diseases of central nervous system (ICD-9-CM code 048), specific diseases due to coxsackievirus (ICD-9-CM code 074), echovirus infection in conditions classified elsewhere and of unspecified site (ICD-9-CM code 079.1), and coxsackievirus infection in conditions classified elsewhere and of unspecified site (ICD-9-CM code 079.2). Children with poliovirus infection (ICD-9-CM code 045) and rhinovirus infection (ICD-9-CM code 079.3) were not included in this study. The date of enteroviral infection was defined as the index date. For each child with enteroviral infection, one random child without enteroviral infection matched by sex, age (within a 1-year interval), urbanization of residential area, parental occupation, and the year of enteroviral infection was enrolled to form the comparison cohort. Children whose date of birth or sex were missing in the records and those with pre-existing nephrotic syndrome (ICD-9-CM code 581) were excluded from this study. In addition, we excluded patients who had diseases that were possibly associated with secondary nephrotic syndrome, namely HIV infection (ICD-9-CM codes 042–044), all diabetes mellitus (ICD-9-CM code 250), autoimmune diseases except type I diabetes mellitus (ICD-9-CM codes 710.0, 710.1, 710.2, 710.3, 714, 725), hepatitis B virus infection (ICD-9-CM codes 070.2–070.3), hepatitis C virus infection (ICD-9-CM codes 070.41, 070.44, 070.51, 070.54, 070.7, V02.62), cancer (ICD-9-CM codes 140–208), amyloidosis (ICD-9-CM codes 277.3), sarcoidosis (ICD-9-CM codes 135, 321.4), herpes zoster infection (ICD-9-CM code 053), and syphilis (ICD-9-CM codes 090–097, 104.0, 647.0).
Primary outcome
The study outcome was a diagnosis of nephrotic syndrome during an 8-year follow-up period. Each child was followed from the index date until either the development of nephrotic syndrome, withdrawal of the insurance program, death, or December 31, 2008, whichever occurred earlier. Comorbidities determined for each child included atopic dermatitis (ICD-9-CM code 691.8), allergic rhinitis (ICD-9-CM code 477), and bronchial asthma (ICD-9-CM code 493).
Statistical analyses
Sociodemographic variables analyzed in this study included age, sex, urbanization level, and parental occupation (white-collar jobs, blue-collar jobs, and others). The urbanization level was categorized into 4 levels that were based on the population density of the residential area [18]. Level 1 was the most urbanized and level 4 was the least urbanized. Distributions of sociodemographic variables in the enterovirus-infected and non-enterovirus-infected cohorts were examined using chi-square tests for categorical variables and Student t tests for continuous variables. Kaplan-Meier analyses were performed for determining the cumulative incidence of nephrotic syndrome, and the log-rank test was used to calculate the difference between the enterovirus- and non-enterovirus-infected cohorts. The incidence density of nephrotic syndrome was estimated by dividing the number of nephrotic syndrome with the number of person-years for different risk factors stratified by age, sex, urbanization level, parental occupation, and comorbidities. Univariable and multivariable Cox proportion hazard regression models were used to examine the effect of enteroviral-infection on the risk of nephrotic syndrome and reported as a hazard ratio (HR) with a 95% confidence interval (CI). Multivariable models were used to determine the risk of nephrotic syndrome after adjustment for the variables. SAS statistical software package (Version 9.3 for Windows; SAS Institute, Inc., Cary, NC, USA) was used for analyzing the data. A p-value less than 0.05 was considered statistically significant.
Results
This study included 280,087 enterovirus-infected children and 280,085 non-enterovirus-infected children. Table 1 presents the sociodemographic variables and comorbidities of both cohorts. The mean age of the enterovirus-infected children was 2.38 years (standard deviation, 1.87 years). Boys accounted for 53.7% of all patients and 55% of children were <2 years. More than half of the children (55.5%) lived in higher urbanization regions (level 1 and level 2), and parents of 64% of the children were white-collar workers. Compared with the non-enterovirus-infected cohort, all allergies were more prevalent in the enterovirus-infected cohort (p <0.001).
The mean (± standard deviation) duration of follow-up was 5.53 (± 2.26) years and 5.51 (± 2.26) years in the enterovirus- and non-enterovirus-infected cohorts, respectively. Kaplan-Meier analyses revealed that the enterovirus-infected cohort had a higher cumulative incidence of nephrotic syndrome than did the non-enterovirus-infected cohort (log-rank test, p = 0.01, Fig 1). The overall incidence of nephrotic syndrome for enterovirus-infected and non-enterovirus-infected children were 2.65 and 2.21 per 10,000 person-years, respectively (Table 2). After adjustment for age, sex, urbanization level, parental occupation, and allergic diseases, the multivariable analyses revealed that children with enteroviral infection were associated with an increased risk of nephrotic syndrome compared with those without enteroviral infection (adjusted HR, 1.20; 95% CI, 1.04–1.39; p = 0.01). Boys were at a higher risk for nephrotic syndrome development than were girls (adjusted HR, 1.23; 95% CI, 1.06–1.42). Compared with those living in the most urbanized levels, children in the third highest urbanized level had a higher risk for the nephrotic syndrome development (adjusted HR, 1.31; 95% CI, 1.06–1.62). However, the age at the diagnosis of enteroviral infection, parental occupation, and allergic disease demonstrated no significant difference in the incidence of nephrotic syndrome.
The incidence rates of nephrotic syndrome for enterovirus- and non-enterovirus-infected cohorts were stratified by sex, age, urbanization level, parental occupation, and allergic disease (Table 3). Sex-specific risk analyses revealed that girls with enteroviral infection exhibited a significantly higher risk of nephrotic syndrome than did those who were not infected (adjusted HR, 1.36; 95% CI, 1.09–1.71). Enterovirus-infected children of blue-collar workers had a higher incidence of nephrotic syndrome than did those not infected (adjusted HR, 1.35, 95% CI, 1.01–1.81). The comorbidity-specific analyses revealed that children in the enterovirus-infected cohort who had no atopic dermatitis (adjusted HR, 1.18; 95% CI, 1.02–1.37), allergic rhinitis (adjusted HR, 1.25; 95% CI, 1.07–1.46), and bronchial asthma (adjusted HR, 1.22; 95% CI, 1.05–1.41) had a significantly higher risk of nephrotic syndrome than did children in the non-enterovirus-infected cohort.
We further evaluated the risk of nephrotic syndrome stratified by the subtypes of enteroviral infections (Table 4). A significantly higher risk of nephrotic syndrome was observed in children infected with coxsackievirus (adjusted HR, 1.20; 95% CI, 1.04–1.39) than in non-enterovirus-infected children. Further analyses revealed that children with herpangina exhibited an increased risk of nephrotic syndrome (adjusted HR, 1.20; 95% CI, 1.03–1.40) whereas those with hand-foot-and-mouth disease did not (adjusted HR, 1.24; 95% CI, 0.97–1.57).
Discussion
This large retrospective cohort study revealed a 1.20-fold increased risk of nephrotic syndrome in children with enteroviral infections, particularly in those infected with coxsackievirus.
Enteroviral infections are very common in children. These viruses are associated with a broad spectrum of manifestations, ranging from minor febrile illness to severe and life-threatening diseases. For example, coxsackievirus infections in infants can result in hand-foot-and-mouth disease, myocarditis, meningitis, and encephalitis [19]. Coxsackievirus A24 and enterovirus 70 are associated with acute hemorrhagic conjunctivitis [20]. Recently, some high virulent strains of enteroviruses have emerged and became a severe threat to children worldwide. Enterovirus 71 causes large outbreaks of diseases in Asia, including hand-foot-and-mouth disease, myocaridits, pulmonary edema, acute flaccid paralysis, meningitis, and encephalitis (particularly brain stem encephalitis) [6,21]. A large outbreak of severe respiratory illness caused by enterovirus 68 occurred in the United States and Canada during 2014 [22]. The Centers for Disease Control and Prevention reported 1,153 patients with severe respiratory illness infected by enterovirus 68, including 14 deaths in children [23].
The involvement of kidney in patients infected with enterovirus had been reported since the 1960s. Burch and Colcolough [8] detected coxsackievirus B antigen in the kidney and heart of a patient with nephritis and pancarditis, and several reports of similar findings have since been described [9–11]. Coxsackieviruses B were reported to infect human glomerular and tubular cell lines, produce cytopathologic changes, and impair the phagocytic and contractile activity of mesangial cells [24]. The coxsackievirus and adenovirus receptor have been identified on the cell membrane of the kidney [15], the host receptor allowing these viruses to enter into the cells [25,26]. Moreover, another receptor ubiquitously expressed in renal tissue, namely scavenger receptor class B member 2 (also known as lysosomal integral membrane protein II and CD36b like-2), permit the entry of enteroviruses, including enterovirus 71 and coxsackievirus, into the kidney [16,27].
Incidence of nephrotic syndrome varies by ethnicity, race, and geographic region [1,2,28] and is more common in boys than in girls (male: female ratio range of 1.2:1–2.5:1) [1,28]. An epidemiologic study in Taiwan revealed an average incidence rate of 5.66 per 100,000 children per year [4], higher than most reports from Western countries [28–30]. In addition, a male preponderance (male: female ratio, 1.91:1) of nephrotic syndrome was demonstrated in Taiwan [4]. In our study, the multivariable model revealed that boys had a 1.23-fold increased risk of nephrotic syndrome compared with girls, and the reason for this difference remains unclear.
Association between allergic diseases and nephrotic syndrome has been reported [31–34]. Meadow et al. first described a higher incidence of allergy in children with corticosteroid-responsive nephrotic syndrome [34]. Immune responses are critical in the pathogenesis of both allergic diseases and nephrotic syndrome [35]. In our study, patients with allergic diseases did not have a significantly higher risk of nephrotic syndrome after adjustment for age, sex, urbanization level, parental occupation, and enteroviral infection status. The risk for the development of nephrotic syndrome in enterovirus-infected children was only significant among those without allergic diseases. This inconsistency between our study and earlier studies may be due to differences in the study design. The hygiene hypothesis has suggested a significant inverse association between allergy and exposure to enteroviruses [36,37]. In this study, we identified enteroviral infection to be a significant factor for development of nephrotic syndrome. When being taken into consideration of enterovirus, the link between allergy and nephrotic syndrome was not significant. Additional studies are warranted to elucidate the interaction among enteroviruses, allergy, and nephrotic syndrome.
Despite this study being a nationwide surveillance based on a large sample with comprehensive demographic characteristics, it has several limitations. First, we excluded cases with underlying causes of secondary nephrotic syndrome. However, some risk factors, such as genetic defect and toxic drugs, were unavailable in the database, and these factors can possibly bias the results of this study. Second, the NHIRD lacks information on histopathologic changes of nephrotic syndrome, namely minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy. Therefore, we could not analyze the association of enteroviral infections with these subtypes of nephrotic syndrome. Third, the included patients of enteroviral infection in this study were based on the ICD-9-CM codes of the NHIRD. The coding and diagnosis of enteroviral infection were made by the clinical physicians. Some of the diagnoses may be based on the symptoms, and others may be based on laboratory confirmation. The database lacked laboratory information about the specimens (stool, blood, cerebrospinal fluid, and nasopharyngeal swab) and the diagnostic techniques (direct fluorescent antibody method, serology, culture, and polymerase chain reaction). Fourth, hand-foot-and-mouth and herpangina, which are the most common types of enteroviral infection, could be diagnosed based on the clinical manifestations. However, a recent study showed that enterovirus could be detected by polymerase chain reaction in only 68.9% of patients with hand-foot-and-mouth and herpangina [38]. The enterovirus prevalence in this study was probably overestimated. On the other hand, many other enteroviral infections are non-specific, such as gastroenteritis, respiratory, and meningitis. The prevalence of enteroviral infection could be underestimated if there was no laboratory confirmation. A recent study using protein microarrays that enables the detection of antiviral antibodies against individual viral proteins from different viral strains may give us much more accurate information of viral infection [39]. Fifth, children with enteroviral infections can be asymptomatic or carriage. Witsø et al. [40] reported that human enterovirus was detected in the stool of 51.3% healthy infants. Moreover, enterovirus can cause respiratory illnesses in children, including nonspecific upper respiratory tract infections, bronchitis, bronchiolitis, and pneumonia [41]. It is likely that a proportion of children with nephrotic syndrome in the non-enterovirus-infected cohort had pauci- or asymptomatic enteroviral infection. This could influence the results of our study. Finally, this study used a database relying on ICD-9-CM diagnostic codes, and inaccurate coding maybe present although several studies have proved the accuracy of the database [42,43].
Conclusions
Nephrotic syndrome is a critical renal disease in children. This large nationwide cohort study revealed an association between enteroviral infection and nephrotic syndrome. Additional studies are warranted to understand the pathogenesis of enteroviral infections on nephrotic syndrome.
Acknowledgments
This study is supported in part by Taiwan Ministry of Health and Welfare Clinical Trial and Research Center of Excellence (MOHW105-TDU-B-212-133019), China Medical University Hospital, Academia Sinica Taiwan Biobank Stroke Biosignature Project (BM10501010037), NRPB Stroke Clinical Trial Consortium (MOST 104-2325-B-039–005), Tseng-Lien Lin Foundation, Taichung, Taiwan, Taiwan Brain Disease Foundation, Taipei, Taiwan, and Katsuzo and Kiyo Aoshima Memorial Funds, Japan; and CMU under the Aim for Top University Plan of the Ministry of Education, Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding received for this study.
Author Contributions
- Conceived and designed the experiments: JNL CHK.
- Analyzed the data: JNL CLL CHY MCL CHL HHL CHK.
- Wrote the paper: JNL CLL CHY MCL CHL HHL CHK.
- Final approval of manuscript: JNL CLL CHY MCL CHL HHL CHK. Collection and assembly of data: CLL CHK.
References
- 1. Andolino TP, Reid-Adam J. Nephrotic syndrome. Pediatr Rev. 2015;36: 117–125. pmid:25733763
- 2. Eddy AA, Symons JM. Nephrotic syndrome in childhood. Lancet. 2003;362: 629–639. pmid:12944064
- 3. Metz DK, Kausman JY. Childhood nephrotic syndrome in the 21st century: What’s new? J Paediatr Child Health. 2014 Sep 30 [Epub ahead of print].
- 4. Chang JW, Tsai HL, Yang LY, Chen TJ. Epidemiology and predictors of end-stage renal disease in Taiwanese children with idiopathic nephrotic syndrome. J Epidemiol. 2012;22: 517–522. pmid:22971550
- 5. Abzug MJ. The enteroviruses: problems in need of treatments. J Infect. 2014;68 Suppl 1: S108–114. pmid:24119825
- 6. Solomon T, Lewthwaite P, Perera D, Cardosa MJ, McMinn P, Ooi MH. Virology, epidemiology, pathogenesis, and control of enterovirus 71. Lancet Infect Dis. 2010;10: 778–790. pmid:20961813
- 7.
Centers for Disease Control and Prevention. Non-Polio Enterovirus, Overview Non-Polio Enteroviruses, Picornavirus. Available: http://www.cdc.gov/non-polio-enterovirus/about/overview.html. Accessed 17 March 2015.
- 8. Burch GE, Colcolough HL. Progressive Coxsackie viral pancarditis and nephritis. Ann Intern Med. 1969;71: 963–970. pmid:4902582
- 9. Bayatpour M, Zbitnew A, Dempster G, Miller KR. Role of coxsackievirus B4 in the pathogenesis of acute glomerulonephritis. Can Med Assoc J. 1973;109: 873 passim. pmid:4750301
- 10. Aronson MD, Phillips CA. Coxsackievirus B5 infections in acute oliguric renal failure. J Infect Dis. 1975;132: 303–306. pmid:1159332
- 11. Burch G, Harb J, Hiramoto Y. Coxsackie B4 viral infection of the human kidney. J Urol. 1974;112: 714–722. pmid:4612174
- 12. Sun SC, Lai CH, Chen ST, Schaeffer BT. Evolution of chronic glomerulonephritis induced in mice by ECHO-9 and Coxsackie B 1 viruses. J Pathol. 1971;104: 53–57. pmid:4105476
- 13. Zhou HT, Wang B, Che XY. Nephrotic syndrome in hand, foot and mouth disease caused by coxsackievirus A16: a case report. Int J Infect Dis. 2014;28: 1–2. pmid:25124453
- 14. Pasch A, Frey FJ. Coxsackie B viruses and the kidney—a neglected topic. Nephrol Dial Transplant. 2006;21: 1184–1187. pmid:16490748
- 15. Nagai M, Yaoita E, Yoshida Y, Kuwano R, Nameta M, Ohshiro K, et al. Coxsackievirus and adenovirus receptor, a tight junction membrane protein, is expressed in glomerular podocytes in the kidney. Lab Invest. 2003;83: 901–911. pmid:12808125
- 16. Nishimura Y, Shimizu H. Cellular receptors for human enterovirus species a. Front Microbiol. 2012;3: 105. pmid:22470371
- 17.
National Health Research Institutes. National Health Insurance Research Database. Available: http://nhird.nhri.org.tw/en/index.html. Accessed 14 April 2015.
- 18. Liu CY, Hung YT, Chuang YL, Chen YJ, Weng WS, Liu JS, et al. Incorporating development stratification of Taiwan townships into sampling design of large scale health interview survey. J Health Manag. 2006;14: 1–22.
- 19. Rhoades RE, Tabor-Godwin JM, Tsueng G, Feuer R. Enterovirus infections of the central nervous system. Virology. 2011;411: 288–305. pmid:21251690
- 20. Zhao Y, Liu J, Zhang H, Guo C, Xia L, Yang F, et al. Complete genome analysis of coxsackievirus A24 isolated in Yunnan, China, in 2013. Arch Virol. 2016;161: 1705–1709. pmid:26935916
- 21. Lee TC, Guo HR, Su HJJ, Yang YC, Chang HL, Chen KT. Diseases caused by enterovirus 71 infection. Pediatr Infect Dis J. 2009;28: 904–910. pmid:20118685
- 22. Midgley CM, Watson JT, Nix WA, Curns AT, Rogers SL, Brown BA, et al. Severe respiratory illness associated with a nationwide outbreak of enterovirus D68 in the USA (2014): a descriptive epidemiological investigation. Lancet Respir. Med 2015;3: 879–887. pmid:26482320
- 23.
Centers for Disease Control and Prevention. Non-Polio Enterovirus, About EV-D68, Enterovirus D68. Available: http://www.cdc.gov/non-polio-enterovirus/about/ev-d68.html. Accessed 12 June 2016.
- 24. Conaldi PG, Biancone L, Bottelli A, De Martino A, Camussi G, Toniolo A. Distinct pathogenic effects of group B coxsackieviruses on human glomerular and tubular kidney cells. J Virol. 1997;71: 9180–9187. pmid:9371576
- 25. Bergelson JM, Cunningham JA, Droguett G, Kurt-Jones EA, Krithivas A, Hong JS, et al. Isolation of a common receptor for Coxsackie B viruses and adenoviruses 2 and 5. Science. 1997;275: 1320–1323. pmid:9036860
- 26. Tomko RP, Xu R, Philipson L. HCAR and MCAR: the human and mouse cellular receptors for subgroup C adenoviruses and group B coxsackieviruses. Proc Natl Acad Sci U S A. 1997;94: 3352–3356. pmid:9096397
- 27. Eskelinen EL, Tanaka Y, Saftig P. At the acidic edge: emerging functions for lysosomal membrane proteins. Trends Cell Biol. 2003;13: 137–145. pmid:12628346
- 28. El Bakkali L, Rodrigues Pereira R, Kuik DJ, Ket JCF, van Wijk JAE. Nephrotic syndrome in The Netherlands: a population-based cohort study and a review of the literature. Pediatr Nephrol. 2011;26: 1241–1246. pmid:21533870
- 29. Wong W. Idiopathic nephrotic syndrome in New Zealand children, demographic, clinical features, initial management and outcome after twelve-month follow-up: results of a three-year national surveillance study. J Paediatr Child Health. 2007;43: 337–341. pmid:17489822
- 30. Sharples PM, Poulton J, White RH. Steroid responsive nephrotic syndrome is more common in Asians. Arch Dis Child. 1985;60: 1014–1017. pmid:4073933
- 31. Wei CC, Tsai JD, Lin CL, Shen TC, Li TC, Chung CJ. Increased risk of idiopathic nephrotic syndrome in children with atopic dermatitis. Pediatr Nephrol. 2014;29: 2157–2163. pmid:25034498
- 32. Wei CC, Lin CL, Shen TC, Sung FC. Occurrence of common allergic diseases in children with idiopathic nephrotic syndrome. J Epidemiol. 2015;25: 370–377. pmid:25843432
- 33. Lin CY, Lee BH, Lin CC, Chen WP. A study of the relationship between childhood nephrotic syndrome and allergic diseases. Chest. 1990;97: 1408–1411. pmid:2347227
- 34. Meadow SR, Sarsfield JK, Scott DG, Rajah SM. Steroid-responsive nephrotic syndrome and allergy: immunological studies. Arch Dis Child. 1981;56: 517–524. pmid:7271285
- 35. Cheung W, Wei CL, Seah CC, Jordan SC, Yap HK. Atopy, serum IgE, and interleukin-13 in steroid-responsive nephrotic syndrome. Pediatr Nephrol. 2004;19: 627–632. pmid:15064938
- 36. Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299: 1259–1260. pmid:2513902
- 37. Korhonen L, Kondrashova A, Tauriainen S, Haapala AM, Huhtala H, Ilonen J, et al. Enterovirus infections in early childhood and the risk of atopic disease—a nested case-control study. Clin Exp Allergy. 2013;43: 625–632. pmid:23711124
- 38. Puenpa J, Mauleekoonphairoj J, Linsuwanon P, Suwannakarn K, Chieochansin T, Korkong S, et al. Prevalence and characterization of enterovirus infections among pediatric patients with hand foot mouth disease, herpangina and influenza like illness in Thailand, 2012. PLOS ONE. 2014;9: e98888. pmid:24887237
- 39. Bian X, Wallstrom G, Davis A, Wang J, Park J, Throop A, et al. Immunoproteomic Profiling of Antiviral Antibodies in New-Onset Type 1 Diabetes Using Protein Arrays. Diabetes. 2016;65: 285–296. pmid:26450993
- 40. Witsø E, Palacios G, Cinek O, Stene LC, Grinde B, Janowitz D, et al. High prevalence of human enterovirus a infections in natural circulation of human enteroviruses. J Clin Microbiol. 2006;44: 4095–4100. pmid:16943351
- 41. Jacques J, Moret H, Minette D, Lévêque N, Jovenin N, Deslée G, et al. Epidemiological, molecular, and clinical features of enterovirus respiratory infections in French children between 1999 and 2005. J Clin Microbiol. 2008;46: 206–213. pmid:18003804
- 42. Yu YB, Gau JP, Liu CY, Yang MH, Chiang SC, Hsu HC, et al. A nationwide analysis of venous thromboembolism in 497,180 cancer patients with the development and validation of a risk-stratification scoring system. Thromb Haemost. 2012;108: 225–235. pmid:22534880
- 43. Cheng CL, Kao YH, Lin SJ, Lee CH, Lai ML. Validation of the National Health Insurance Research Database with ischemic stroke cases in Taiwan. Pharmaco epidemiol Drug Saf. 2011;20: 236–242.