Original article Korean J Pediatr 2014;57(10):440-444 http://dx.doi.org/10.3345/kjp.2014.57.10.440 pISSN 1738-1061•eISSN 2092-7258
Korean J Pediatr
Serum interleukin-1beta and tumor necrosis factor-alpha in febrile seizures: is there a link? Abolfazl Mahyar, MD, Parviz Ayazi, MD, Reza Orangpour, MD, Mohammad Mahdi Daneshi-Kohan, LD, Mohammad Reza Sarokhani, LD, Amir Javadi, PhD, Morteza Habibi MD, Mousa Talebi-Bakhshayesh, MSc Department of Pediatrics, Qazvin Children Hospital, Qazvin University of Medical Sciences, Qazvin, Iran
Purpose: Febrile seizures are induced by fever and are the most common type of seizures in children. Although numerous studies have been performed on febrile seizures, their pathophysiology remains unclear. Recent studies have shown that cytokines may play a role in the pathogenesis of febrile seizures. The present study was conducted to identify potential links between serum interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and febrile seizures. Methods: Ninety-two patients with simple or complex febrile seizures (46 patients per seizure type), and 46 controls with comparable age, sex, and severity of temperature were enrolled. Results: The median concentrations of serum IL-1β in the simple, complex febrile seizure, and control groups were 0.05, 0.1, and 0.67 pg/mL, respectively (P=0.001). Moreover, the median concentrations of TNF-α in the simple, complex febrile seizure, and control groups were 2.5, 1, and 61.5 pg/mL, respectively (P=0.001). Furthermore, there were significant differences between the case groups in serum IL-1β and TNF-α levels (P30 minutes3-8). This type of febrile seizure occurs in 2%–9% of children9,10). While several cohort studies suggest that prognosis of febrile seizures is often good, epilepsy is observed in 5.4% of these patients2,5,11,12). Although numerous studies have been performed on febrile seizures, their exact pathophysiology remains unknown13,14). Cytokines may be one of the factors involved in the pathogenesis of febrile seizures15-18). Cytokines are hormonal mediators involved in several infectious and immunological phenomena. Interleukin-1beta (IL-1β) and tumor necrosis factoralpha (TNF-α) are the major cytokines15,16). Tutuncuoglu et al.17) reported that increased production of IL-1β is involved in the pathogenesis of febrile seizures. In contrast, Tomoum et al.18) suggested that IL-1β do not play any roles in the pathogenesis of febrile
440
http://dx.doi.org/10.3345/kjp.2014.57.10.440
Copyright © 2014 by The Korean Pediatric Society This is an open-access article distributed under the terms of the Creative Commons Attribution NonCommercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Korean J Pediatr 2014;57(10):440-444
seizures. Because of these controversial opinions, the present study was conducted to investigate the relationship between serum IL-1β and TNF-α with febrile seizures in children.
Materials and methods This case-control study was performed at Qazvin Children Hospital affiliated to the Qazvin University of Medical Sci ences in Qazvin, Iran in 2012. Case groups (92 patients) were consecutively selected from children admitted to the hospital after simple and complex febrile seizures. Control group comprised 46 febrile children without seizures. The ages of all patients were between 6 and 60 months. Sample size was calculated to determine 95% confidence coefficient and 80% power for statistical analysis16). Consecutive sampling continued until the desired sample size was reached. Inclusion criteria for the febrile seizure groups were: (1) fever≥38°C, (2) presence of simple febrile seizure (generalized seizure lasting for 15 minutes that recurred within 24 hours)2,3). Patients with central nervous system infections, electrolyte imbalance, metabolic disorders, neurological deficits, and a history of febrile seizures were excluded. The control group included febrile children without seizures who visited the hospital clinic because of common febrile diseases such as upper respiratory tract infection. Febrile diseases (viral or bacterial) were diagnosed according to clinical findings. Body temperature (axillary) was measured using a standard method3). The ethics committee of the Research Department in the Qazvin University of Medical Sciences (project no. 284) approved the study. All parents were provided information regarding the research method in simple language. The children were included
in the study after their parents agreed and signed the informed consent form. Four milliliters of blood was taken from the peripheral vessels of children in all the groups, and serum was obtained by centrifugation at 3,000 rpm for 5 minutes at 4°C. The serum was then poured into acid-washed tubes and stored in a refrigerator at −20°C until IL-1β and TNF-α assay. In the febrile seizure groups, blood samples were collected within 5 hours after the occurrence of a seizure episode16,19). Concentrations of serum IL-1β and TNF-α were measured using enzyme-linked immunosorbent assay and commercially available kits (Cat. No. BE51011 and Cat.No.BE58351; IBL Co., Hamburg, Germany). All the samples were measured in duplicates to improve accuracy. Results were analyzed by chi-square test, analysis of variance, and nonparametric tests (Mann-Whitney U test and KruskalWallis test). Cytokine levels were expressed as median and range, whereas variable values except age were expressed as mean± standard deviation. Statistical calculations were performed using SPSS ver. 15 (SPSS Inc., Chicago, IL, USA). P0.05) (Table 1). The median concentrations of serum IL-1β in simple, complex febrile seizures and control groups were 0.05, 0.1, and 0.67 pg/
Table 1. Groupwise comparison of patient variables Simple
Complex
Control
P value
25/21
26/20
26/20
0.97
Age (mo)
20.5 (8–59)
18 (6–59)
14 (6–51)
0.12
Severity of temprature (°C)
38.7±0.43
38.6±0.29
38.6±0.33
0.45
Fever duration (day)
1.28±0.58
1.34±0.78
1.31±0.72
0.916
29/17
33/12
28/18
0.41
Variable Sex Male/female
Etiology of infection (viral/bacterial)
Table 2. Comparison of serum IL-1β and TNF-α in the case and control groups Serum cytokines (pg/mL)
Simple
Complex
Control
P value
IL-1β
0.05 (0.05–9.7)
0.1 (0.1–17.4)
0.67 (0.1–15.3)
0.001
TNF
2.5 (1.9–960)
1 (1–735)
61.5 (4–4700)
0.001
IL-1β, Interleukine 1 beta; TNF, Tumor necrotizing factor.
http://dx.doi.org/10.3345/kjp.2014.57.10.440
441
A Mahyar, et al. • Serum interleukin-1β and tumor necrosis factor-α in febrile seizures mL, respectively (P
Korean J Pediatr
Serum interleukin-1beta and tumor necrosis factor-alpha in febrile seizures: is there a link? Abolfazl Mahyar, MD, Parviz Ayazi, MD, Reza Orangpour, MD, Mohammad Mahdi Daneshi-Kohan, LD, Mohammad Reza Sarokhani, LD, Amir Javadi, PhD, Morteza Habibi MD, Mousa Talebi-Bakhshayesh, MSc Department of Pediatrics, Qazvin Children Hospital, Qazvin University of Medical Sciences, Qazvin, Iran
Purpose: Febrile seizures are induced by fever and are the most common type of seizures in children. Although numerous studies have been performed on febrile seizures, their pathophysiology remains unclear. Recent studies have shown that cytokines may play a role in the pathogenesis of febrile seizures. The present study was conducted to identify potential links between serum interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and febrile seizures. Methods: Ninety-two patients with simple or complex febrile seizures (46 patients per seizure type), and 46 controls with comparable age, sex, and severity of temperature were enrolled. Results: The median concentrations of serum IL-1β in the simple, complex febrile seizure, and control groups were 0.05, 0.1, and 0.67 pg/mL, respectively (P=0.001). Moreover, the median concentrations of TNF-α in the simple, complex febrile seizure, and control groups were 2.5, 1, and 61.5 pg/mL, respectively (P=0.001). Furthermore, there were significant differences between the case groups in serum IL-1β and TNF-α levels (P30 minutes3-8). This type of febrile seizure occurs in 2%–9% of children9,10). While several cohort studies suggest that prognosis of febrile seizures is often good, epilepsy is observed in 5.4% of these patients2,5,11,12). Although numerous studies have been performed on febrile seizures, their exact pathophysiology remains unknown13,14). Cytokines may be one of the factors involved in the pathogenesis of febrile seizures15-18). Cytokines are hormonal mediators involved in several infectious and immunological phenomena. Interleukin-1beta (IL-1β) and tumor necrosis factoralpha (TNF-α) are the major cytokines15,16). Tutuncuoglu et al.17) reported that increased production of IL-1β is involved in the pathogenesis of febrile seizures. In contrast, Tomoum et al.18) suggested that IL-1β do not play any roles in the pathogenesis of febrile
440
http://dx.doi.org/10.3345/kjp.2014.57.10.440
Copyright © 2014 by The Korean Pediatric Society This is an open-access article distributed under the terms of the Creative Commons Attribution NonCommercial License (http://creativecommons.org/ licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Korean J Pediatr 2014;57(10):440-444
seizures. Because of these controversial opinions, the present study was conducted to investigate the relationship between serum IL-1β and TNF-α with febrile seizures in children.
Materials and methods This case-control study was performed at Qazvin Children Hospital affiliated to the Qazvin University of Medical Sci ences in Qazvin, Iran in 2012. Case groups (92 patients) were consecutively selected from children admitted to the hospital after simple and complex febrile seizures. Control group comprised 46 febrile children without seizures. The ages of all patients were between 6 and 60 months. Sample size was calculated to determine 95% confidence coefficient and 80% power for statistical analysis16). Consecutive sampling continued until the desired sample size was reached. Inclusion criteria for the febrile seizure groups were: (1) fever≥38°C, (2) presence of simple febrile seizure (generalized seizure lasting for 15 minutes that recurred within 24 hours)2,3). Patients with central nervous system infections, electrolyte imbalance, metabolic disorders, neurological deficits, and a history of febrile seizures were excluded. The control group included febrile children without seizures who visited the hospital clinic because of common febrile diseases such as upper respiratory tract infection. Febrile diseases (viral or bacterial) were diagnosed according to clinical findings. Body temperature (axillary) was measured using a standard method3). The ethics committee of the Research Department in the Qazvin University of Medical Sciences (project no. 284) approved the study. All parents were provided information regarding the research method in simple language. The children were included
in the study after their parents agreed and signed the informed consent form. Four milliliters of blood was taken from the peripheral vessels of children in all the groups, and serum was obtained by centrifugation at 3,000 rpm for 5 minutes at 4°C. The serum was then poured into acid-washed tubes and stored in a refrigerator at −20°C until IL-1β and TNF-α assay. In the febrile seizure groups, blood samples were collected within 5 hours after the occurrence of a seizure episode16,19). Concentrations of serum IL-1β and TNF-α were measured using enzyme-linked immunosorbent assay and commercially available kits (Cat. No. BE51011 and Cat.No.BE58351; IBL Co., Hamburg, Germany). All the samples were measured in duplicates to improve accuracy. Results were analyzed by chi-square test, analysis of variance, and nonparametric tests (Mann-Whitney U test and KruskalWallis test). Cytokine levels were expressed as median and range, whereas variable values except age were expressed as mean± standard deviation. Statistical calculations were performed using SPSS ver. 15 (SPSS Inc., Chicago, IL, USA). P0.05) (Table 1). The median concentrations of serum IL-1β in simple, complex febrile seizures and control groups were 0.05, 0.1, and 0.67 pg/
Table 1. Groupwise comparison of patient variables Simple
Complex
Control
P value
25/21
26/20
26/20
0.97
Age (mo)
20.5 (8–59)
18 (6–59)
14 (6–51)
0.12
Severity of temprature (°C)
38.7±0.43
38.6±0.29
38.6±0.33
0.45
Fever duration (day)
1.28±0.58
1.34±0.78
1.31±0.72
0.916
29/17
33/12
28/18
0.41
Variable Sex Male/female
Etiology of infection (viral/bacterial)
Table 2. Comparison of serum IL-1β and TNF-α in the case and control groups Serum cytokines (pg/mL)
Simple
Complex
Control
P value
IL-1β
0.05 (0.05–9.7)
0.1 (0.1–17.4)
0.67 (0.1–15.3)
0.001
TNF
2.5 (1.9–960)
1 (1–735)
61.5 (4–4700)
0.001
IL-1β, Interleukine 1 beta; TNF, Tumor necrotizing factor.
http://dx.doi.org/10.3345/kjp.2014.57.10.440
441
A Mahyar, et al. • Serum interleukin-1β and tumor necrosis factor-α in febrile seizures mL, respectively (P
