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ORIGINAL ARTICLE
Genetic analysis of interleukin-1 receptor antagonistand interleukin-1b single-nucleotide polymorphismsC2511T and C+3953T in alopecia areata: susceptibilityand severity association
Suad AlFadhli • Arti Nanda
Received: 20 December 2012 / Accepted: 29 January 2013
� Springer-Verlag Italia 2013
Abstract The present study was aimed to explore the
effect of two selected polymorphisms from interleukin-1b(IL-1b) gene [SNPs -511 and ?3953] and a variable
number of tandem repeat (VNTR) from interleukin-1
receptor antagonist (IL-1RN) on the susceptibility and
severity of alopecia areata (AA) in Kuwaiti subjects. IL-1bSNPs C-511T, C?3953T, and IL-1RN VNTR were
screened in 96 alopecia patients classified clinically,
according to the disease severity as patchy (P), semiuni-
versalis (SU), and universalis (U), and in 100 ethnically
matched healthy controls. Polymerase chain reaction fol-
lowed by restriction fragment length polymorphism and
direct DNA sequencing were employed for genotyping.
Comparing the stratified AA cases based on severity, IL-bSNP C-511T showed a significant association (genotype
and allelotype levels p = 0.03 and p = 0.028, respec-
tively). Genotype CC was 50 % more frequent in U cases
than in P or SU. When P and SU were grouped and tested
against U, a significant difference was observed (genotype
and allelotype levels p = 0.006 and p = 0.008, respec-
tively). Compared to genotype CT, carriers of IL-1b -511
CC genotype showed an increased risk to develop severe
AA (p = 0.004, OR = 4.14, 95 % CI = 1.61–10.69). Four
alleles and genotypes (1/1, 1/3, 1/4, and 2/2) of IL-1RN
VNTR were detected in AA patients while only two (1/1
and 1/3) in controls. IL-1RN VNTR showed genotype and
allelotype association with AA (p = 0.05 and p = 0.025,
respectively). Our results showed that IL-1b and IL-1RN
VNTR are significantly associated with the susceptibility to
alopecia areata. Allele C of the IL-b C-511T SNP is
linked to the severe form of AA.
Keywords Alopecia areata � Interleukin-1b � Interleukin-
1 receptor antagonist � Susceptibility � Severity
Introduction
Alopecia areata (AA) is a prevalent inflammatory skin
disease and represent 6.7 % of all skin disease among
children in Kuwait [1–3]. The main etiology of this disease
is yet to be defined, and there are accumulative evidence
that AA is a complex multigenetic trait with components of
inherited predisposition [4]. Very limited studies have been
published from Kuwait and the Middle East and none were
relevant to its genetics [1–3].
The susceptibility or severity of a number of disorders is
proven to be influenced by the possession of specific alleles
of polymorphic genes [5]. One of the several loci shown to
have significant linkage disequilibrium with AA is located
on chromosome 2q13-21. This includes the IL-1 (Inter-
leukin-1) cluster genes spanning 430-kb region harboring:
interleukin-1 alpha (IL-1a), interleukin-1 beta (IL-1b), and
IL-1 receptor antagonist gene (IL-1RN) [6]. Variations in
these genes can modulate the effectiveness of IL-1 sig-
naling and thereby predispose to disease. Besides AA [7],
the IL-1 cluster genes are involved in cancer and several
S. AlFadhli (&)
Department of Medical Laboratory Sciences, Faculty of Allied
Health Sciences, Kuwait University, PO Box 31470,
Sulaibekhat, Kuwait, Kuwait
e-mail: [email protected]; [email protected]
S. AlFadhli
Medical Laboratory Sciences, Kuwait University,
Jabriya, Kuwait
A. Nanda
Asad Al-Hamad Dermatology Centre, Al Sabah Hospital,
Ministry of Health, Shuwaikh, Kuwait
e-mail: [email protected]
123
Clin Exp Med
DOI 10.1007/s10238-013-0228-7
chronic inflammatory diseases [8, 9] such as systemic lupus
erythematosus [10]; Lichen sclerosis [11]; ulcerative colitis
[12, 13]; chronic hepatitis B [14]; periodontal disease in
type 2 diabetes [15]; and esophageal, gastric, and colorectal
carcinomas [9].
IL-1b is an important mediator of the inflammatory
response and is involved in a variety of cellular activities,
including cell proliferation, differentiation, and apoptosis.
Polymorphisms in IL-1b gene have been reported to affect
the level of gene expression in peripheral monocytes [16,
17]. Biallelic polymorphisms at positions -511 (rs16944,
C [ T) in the promoter region and ?3954 (rs1143634,
C [ T) in exon 5 [18] have potential functional signifi-
cance in modulating IL-1 protein production and are rela-
ted with the development of some diseases [19]. The IL-1bgene polymorphisms are of particular interest in alopecia
areata, since proinflammatory cytokines are shown to have
implication in the inhibition of human hair growth [20–22].
Furthermore, increased IL-1b mRNA was reported in scalp
biopsies of patients with alopecia totalis compared to those
of healthy controls [20].
IL-1RN competitively inhibits the binding of IL-1a and
IL-1b to IL-1 receptor without triggering signal transduc-
tion and thus regulates their pro-inflammatory actions [23,
24]. Its in vivo importance has been revealed in animal
models and is being evaluated in clinical trials. The well-
characterized polymorphic allele of IL-1RN gene is a
tandem repeat sequence of 86 bp in intron 2 [7]. Five
alleles comprising between two and six repeats of 86-bp
sequence are known. The four-repeats (allele 1) and two-
repeats (allele 2) variants are the most common, whereas
the other alleles rarely occur (\5 %) [25, 26]. Increased
frequency of allele 2 was suggested to be related with
increased susceptibility in several infectious and inflam-
matory diseases [27, 28].
The purpose of this study was to determine the distri-
bution of the aforementioned polymorphisms in IL-1b and
IL-RA in patients with alopecia areata of different disease
severities.
Methods
Study subjects and DNA specimens
A total of 196 age, gender, ethnically, matched subjects
were recruited in this study: 96 AA and 100 healthy con-
trols. AA samples were collected from Asad Al-Hamad
Dermatology Center. The study was approved by the
institution’s Ethics Committee, and all the participants
provided written informed consent. Based on the severity
of hair loss, AA patients were classified into three
subgroups: patchy (P) with less than 25 % hair loss,
semiuniversalis (SU) with 50–100 % hair loss, and uni-
versalis (U) with 100 % hair loss. The distribution of the
cases was 35.4 % P, 35.4 % SU, and 29.1 % U. Healthy
volunteers were randomly selected from five provinces of
Kuwait. Inclusion criteria were general good health and no
first-degree relatives with autoimmune diseases. Exclusion
criteria were any recent history of acute or chronic debil-
itating illness. Ethnic bias within the population studied
was minimized by excluding patients who were not of Arab
origin.
Each participant donated peripheral blood and DNA was
isolated from peripheral nucleated blood cells using Gentra
kit (Minneapolis, USA), according to the manufacturer’s
instructions.
IL-1b SNP -511 and ?3953 genotyping
The polymorphic site at position -511 of the IL-1b gene
was amplified by standard PCR using gene-specific primers
50-TGG CAT TGA TCT GGT TCA TC-30 and 50-GTT
TAG GAA TCT TCC CAC TT-30 [18]. The thermal
amplification program consisted of an initial denaturation
step (5 min at 95 �C), followed by 30 cycles of 1-min
denaturation (94 �C), 1-min annealing (55 �C), and 1-min
elongation (72 �C), with a final extension period of 5 min
at 72 �C. Restriction digestion of the PCR product with
AvaI results in fragments of 190 ? 114 bp (allele 1) and
304 bp (allele 2). The second polymorphic C?3953T was
amplified by PCR using primers 50-AGG TGT CCT CCA
AGA AAT CAA A-30 and 50-GCT TTT TTG CTG TGA
GTC CCG-30 at an annealing temperature of 60 �C for
1 min. Restriction digestion of PCR products with Taq1
results in product of 108 ? 86 bp (allele 1) and the 194 bp
(allele 2). Fragments were separated on 2 % agarose gel
containing ethidium bromide and visualized under UV
light.
IL-1-RA genotyping
The region in the second intron of the IL-1RA gene, con-
taining variable numbers of an identical tandem repeat
(VNTR) of 86 bp, was amplified by PCR using gene-spe-
cific primers 50-CTC AGC AAC ACT CCT AT-30 and 50-TCC TGG TCT GCA GGT AA-30 [23]. PCR conditions
were 95 �C for 5 min, then 30 cycles of 94 �C for 1 min,
60 �C 1 min 72 �C for 2 min. The PCR products of 410 bp
(allele 1, four repeats of 86-bp region), 240 bp (allele 2,
two repeats), 500 bp (allele 3, five repeats), 325 bp (allele
4, three repeats), 59 bp (allele 5, six repeats) were analyzed
on a 2 % agarose gel stained with ethidium bromide.
Genotyping results were confirmed by sequencing ran-
domly selected samples.
Clin Exp Med
123
Statistical analysis
IL-1b (-511 and ?3953) and IL-1RN (intron 2) allelic and
genotype frequencies were calculated in patients with AA
and control subjects. The Hardy–Weinberg equilibrium
(HWE) was calculated using the GenePop web version 4.0
program. No deviation from Hardy–Weinberg equation
was observed for healthy subjects. Comparison of allelic
and genotypes between groups was examined for statistical
significance with chi-square test; p \ 0.05 was consid-
ered statistically significant. The strength of the association
was estimated by odds ratio of risk (OR) and 95 % confi-
dence intervals (CI). Haplotype analysis was carried out
using haploview software (http://www.broadinstitute.org/).
Results
Samples from 196 subjects were chosen as cases and con-
trols for studying the allelic and genotypic distribution of
each polymorphism in Kuwaiti Population. Allele and
genotype distribution of IL-1b C-511T SNP failed to show
any significant association with alopecia areata. Allele T was
detected in 40 % of alopecia areata and 37 % of healthy
subjects. The frequency of CT, CC, and TT genotypes in
patients with alopecia areata was 54, 33, and 13 %, while
those in controls were 54, 35, and 11 %, respectively
(Table 1). No significant difference in allele (x2 = 0.176,
p = 0.675) or genotype (x2 = 0.242, p = 0.886) frequen-
cies of IL-1b C-511T SNP was observed between AA
patients and control subjects when comparing overall data-
set, or age at onset. Similarly, no significant difference was
observed in the allele (x2 = 0.568, p = 0.451) and genotype
frequencies (x2 = 0.633, p = 0.729) of IL-1b C?3953T
SNP of alopecia areata patients when compared to healthy
controls (Table 2). Allele T was detected in 36 % of alopecia
and 32 % of healthy controls. The frequencies of CT, CC,
and TT genotypes in patients with alopecia areata were 51,
39, and 10 %, while those in controls were 48, 44, and 8 %,
respectively, failing to show any significant association.
When the patients were stratified based on their disease
severity, a very significant association was revealed with
SNP C-511T but not SNP C?3953T (Tables 3 and 4). A
clear significant differences among the three various sever-
ity groups (P vs. SU vs. U) was detected when comparing
SNP C-511T frequencies; x2 = 10.7, p = 0.03, and
x2 = 7.15, p = 0.028 for the genotype and allelotype anal-
ysis, respectively. When P ? SU patients were combined
and tested against U cases using 2 9 2 contig analysis for
the SNP C-511T, a significant differences were observed
with x2 = 10.1, p = 0.006, and x2 = 7.03, p = 0.008
genotype and allelotype, respectively. Genotype CC was
found to be 57 % more frequent in the severe form of the
disease (U) than the P and SU. However, CT genotypes were
23 and 29 % P and SU more compared to U cases. Compared
with the CT genotype, carriers of IL-1b -511 CC genotype
had an increased risk to develop severe AA OR = 4.14,
95 % confidence interval (CI) = 1.61–10.69, p = 0.004).
No such significant revealed for SNP C?3953T.
Analysis of IL-1RN marker revealed four alleles in this
study. Allele 1 was predominant in both AA and control
(92 and 93 %. respectively). Alleles 2 and 4 were found in
4 and 2 % of AA patients, respectively, while these alleles
were absent in the controls. Allele 3 was found in 2 % of
AA patients and 7 % in control. Allele distribution between
AA patients and control showed significant association
Table 1 Comparison of IL-1b (-511) polymorphism between patients with alopecia areata and controls
Group
-511 C/T
n Frequency of genotypes (%) Frequency of alleles (%)
CT CC TT C T
Alopecia areata 96 52 (54) 32 (33) 12 (13) 116 (60) 76 (40)
Healthy control 96 52 (54) 34 (35) 10 (11) 120 (63) 72 (37)
Patients versus controls, genotype (df2): x2 = 0.242, p = 0.886; allelotype (df1): x2 = 0.176, p = 0.675
p \ 0.05 was considered to be statistically significant
Table 2 Comparison of IL-1 (?3953) polymorphism between patients with alopecia areata and controls
Group
?3953C/T
n Frequency of genotypes (%) Frequency of alleles (%)
CT CC TT C T
Alopecia areata 96 49 (51) 37 (39) 10 (11) 123 (64) 69 (36)
Healthy control 96 46 (48) 42 (44) 8 (8) 130 (68) 62 (32)
Patients versus controls, genotype (df2): x2 = 0.633, p = 0.729; allelotype (df1): x2 = 0.568, p = 0.451
p \ 0.05 was considered to be statistically significant
Clin Exp Med
123
with x2 = 9.44, df = 3, and p = 0.024. Only four of the
five genotypes of IL-1RN (1/1, 1/3, 1/4, and 2/2) were
detected in this study and their frequencies were 88, 4, 4,
and 4 % in AA patients, while in controls, only two
genotypes were detected (1/1) 86 % and (1/3) 14 %
(Table 5). Genotypic distribution of AA patients showed a
borderline association when compared to control x2 = 7.73
df = 3, and p = 0.052.
Furthermore, the statistical relationships between the
studied markers were analyzed using haploview software.
No statistically significant relationship (p [ 0.05) was
observed between these two markers when haplotype
analysis was carried out using haploview software. How-
ever, analysis using chi-square (2 9 2) contingency table
revealed a suggestive significance between AA patients
and healthy controls with -511 CC and IL-1RA 4, 4 repeat
(p = 0.05, OR = 0.38).
Discussion
Our study was aimed to investigate the role of the IL-1 and
IL-RN in AA pathology in Kuwaiti/Arab patients. There
was no significant association of IL-1b -511 or IL-1b?3954 genotypes with the overall dataset, or age at onset.
However, when stratifying the patients according to the
disease severity, a high significant difference was detected
with SNP IL-1b -511 but not SNP IL1-b ?3954. Geno-
type CT was found to be almost 50 % less in the severe
cases (U) compared to P or SU, while genotype CC was
50 % greater in the severe cases U than the P or SU. Allele
C was significantly higher in the severe cases (U) but T was
much lower in U compared to P or SU. Compared with the
CT genotype, carriers of IL-1b -511 CC genotype had
an increased risk to develop severe AA with OR of 4.14
(95 % CI 1.61–10.69, p = 0.004). The activation of the
Table 3 Comparison of IL-1 (-511) polymorphism between patients with alopecia areata stratified based on the severity of the disease
Group
-511C/T
n Frequency of genotypes (%) Frequency of alleles (%)
CT CC TT C T
Alpecia P 34 20 (59) 8 (23) 6 (18) 36 (53) 32 (47)
Alopecia SU 34 22 (65) 8 (23) 4 (12) 38 (56) 30 (44)
Alopecia U 28 10 (36) 16 (57) 2 (7) 42 (75) 14 (25)
P versus SU versus U: genotype df(4): x2 = 10.7, p = 0.03; allelotype df(2): x2 = 7.15, p = 0.028
P ? SU versus U: genotype df(2): x2 = 10.1, p = 0.006; allelotype df(1): x2 = 7.03, p = 0.008
p \ 0.05 was considered to be statistically significant
Table 4 Comparison of IL-1b ? 3953) polymorphism between patients with alopecia areata stratified based on the severity of the disease
Group
?3953C/T
n Frequency of genotypes (%) Frequency of alleles (%)
CT CC TT C T
Alpecia P 34 14 (42) 17 (50) 3 (8) 48 (71) 20 (29)
Alopecia SU 34 20 (58) 12 (35) 2 (5) 44 (65) 24 (35)
Alopecia U 28 15 (55) 8 (27) 5 (18) 31 (55) 25 (45)
P versus SU versus U: genotype df(4): x2 = 5.3, p = 0.258; allelotype df(2): x2 = 3.1, p = 0.211
P ? SU versus U: genotype df(2): x2 = 0.205, p = 0.258; allelotype df (1): x2 = 2.6, p = 0.107
p \ 0.05 was considered to be statistically significant
Table 5 Comparison of IL-1RN intron 2 polymorphism between patients with alopecia areata and controls
Group
IL-RN
n Frequency of genotypes (%) Frequency of alleles (%)
2/2 1/4 1/1 1/3 1 2 3 4
Patients 98 4 (4) 4 (4) 86 (88) 4 (4) 180 (92) 8 (4) 4 (2) 4 (2)
Controls 42 0 0 36 (86) 6 (14) 78 (93) 0 6 (7) 0
Patients versus controls, df(3), genotype: x2 = 7.73, P = 0.05; allelotype: x2 = 9.44, p = 0.024
p \ 0.05 was considered to be statistically significant
Clin Exp Med
123
inflammatory response system is linked to having C allele
at position -511 in the promoter region of IL-1b and this is
not limited to AA; however, it has been related to the
pathophysiology of various diseases such as schizophrenia
where the frequencies of IL-1b -511C were found to be
significantly higher in schizophrenic patients compared to
controls [24]. In addition, IL-1b -511 CC genotype and C
allele were associated with higher risk of gastroesophageal
reflux disease [25] and with periodontitis [15].
The influence of -511C [ T SNP in the expression of
IL-1b gene was revealed two decades ago by Pociot et al.
[29] who reported a significant increase in the expression
of IL-1b among -511T homozygotes followed by the
heterozygotes individuals, who secreted significantly more
than -511C homozygous individuals. The association of a
gene polymorphism with altered protein production may
occur due to linkage with another marker directly affecting
gene expression. Several studies have previously reported
that IL-1b 511 is almost in total linkage with TATA box
polymorphism -31 C [ T. El-Omar et al. have revealed
that these two polymorphisms are in near-complete linkage
disequilibrium and -31 C [ T markedly affects DNA–
protein interactions in vitro [30]. A complete linkage dis-
equilibrium between these two markers based on a cis
interaction was also reported [31, 32]. Supporting evidence
were provided by Wen et al. who indicated that after the
exposure to LPS, whole blood leukocytes from subjects
with the homozygous haplotype -1470G, -511C, and
-31T (G-C-T) produced more IL-1beta in vitro than those
from subjects with haplotype -1470C, -511T, and -31C
(C-T-C), and that the transcriptional activity of the haplo-
type G-C-T was also higher than that of the haplotype C-T-
C. It is suggested that the haplotypes of the IL-1b promoter
influence the expression and transcriptional activity of the
IL-1beta gene and that the upregulation of IL-1beta gene
expression after LPS exposure in subjects with haplotype
G-C-T may be due to an increased transcriptional activity
of the haplotype (16). These results may possibly suggest
that severe form of AA is associated with increased pro-
duction of IL-1b, regulated in part by the IL-1b -511
polymorphism.
In our study, the overall association between IL-1RN
VNTR and AA was shown to be significant (p = 0.024).
Although allele 1 was predominant in both AA and control,
however, alleles 2 and 4 were merely found in AA with a
low frequencies of 4 and 2 %, respectively. IL-1RN vari-
ants are now known to be associated with the severity of
several other inflammatory autoimmune diseases, including
ulcerative colitis, lichen sclerosus, psoriasis, myasthenia
gravis, multiple sclerosis, and rheumatoid disease. Several
studies have previously reported an association between
the severity of alopecia areata and inheritance of allele 2
[33, 34]. Barahamani et al. [35] have shown that the
increase in the IL-1ra serum level is significantly associ-
ated with AA patients regardless of disease severity or the
presence of atopy. The same researcher group failed to
confirm the association of IL-1RN genotypes with alopecia
universalis [36]. This could be explained as the cohort used
by this group was trios with only 88 individuals catego-
rized as alopecia universalis subjects including both pro-
bands and other affected family members. Since the parents
of the probands are unlikely all to be heterozygous for
IL-1RN variants, the number of transmissions in this study
may be insufficient for statistical power to detect the dif-
ference between the transmitted and non-transmitted
IL-1RN allele 2. The results presented here indicate that
the IL-1b and IL-RA loci act cooperatively in increasing
the risk of alopecia areata. It also suggests that the role of
cytokine promoter SNPs in both susceptibility to and
severity of alopecia areata requires further investigation in
a larger study. To our knowledge, this represents the first
study testing Arab populations.
Acknowledgments This work was supported by Kuwait University
Research Administration Grant NM01/07.
Conflict of interest None.
References
1. Nanda A, Al-Hasawi F, Alsaleh QA (1999) A prospective survey
of pediatric dermatology clinic patients in Kuwait: an analysis of
10,000 cases. Pediatr Dermatol 16:6–11
2. Nanda A, Al-Fouzan AS, Al-Hasawi F (2002) Alopecia areata in
children: a clinical profile. Pediatr Dermatol 19:482–485
3. Nanda A, Alsaleh QA, Al-Hasawi F, Al-Muzairai I (2002) Thy-
roid function, autoantibodies, and HLA tissue typing in children
with alopecia areata. Pediatr Dermatol 19:486–491
4. Alzolibani AA, Zari S, Ahmed AA (2012) Epidemiologic and
genetic characteristics of alopecia areata (part 2). Acta Derma-
tovenerol Alp Panonica Adriat 21:15–19
5. Jiang J, Zhang X, Yang H, Wang W (2009) Polymorphisms of
DNA repair genes: ADPRT, XRCC1, and XPD and cancer risk in
genetic epidemiology. Methods Mol Biol 471:305–333
6. Nicklin MJ, Weith A, Duff GW (1994) A physical map of the
region encompassing the human interleukin-1 alpha, interleukin-
1 beta, and interleukin-1 receptor antagonist genes. Genomics
19:382–384
7. Tarlow JK, Blakemore AI, Lennard A, Solari R, Hughes HN,
Steinkasserer A, Duff GW (1993) Polymorphism in human IL-1
receptor antagonist gene intron 2 is caused by variable numbers
of an 86-bp tandem repeat. Hum Genet 91:403–404
8. Witkin SS, Gerber S, Ledger WJ (2002) Influence of interleukin-
1 receptor antagonist gene polymorphism on disease. Clin Infect
Dis 34:204–209
9. Ito H, Kaneko K, Makino R et al (2007) Interleukin-1beta gene in
esophageal, gastric and colorectal carcinomas. Oncol Rep
18:473–481
10. Blakemore AI, Tarlow JK, Cork MJ, Gordon C, Emery P, Duff
GW (1994) Interleukin-1 receptor antagonist gene polymorphism
as a disease severity factor in systemic lupus erythematosus.
Arthritis Rheum 37:1380–1385
Clin Exp Med
123
11. Clay FE, Cork MJ, Tarlow JK, Blakemore AI, Harrington CI,
Lewis F, Duff GW (1994) Interleukin 1 receptor antagonist gene
polymorphism association with lichen sclerosus. Hum Genet
94:407–410
12. Mansfield JC, Holden H, Tarlow JK, Di Giovine FS, McDowell
TL, Wilson AG, Holdsworth CD, Duff GW (1994) Novel genetic
association between ulcerative colitis and the anti-inflammatory
cytokine interleukin-1 receptor antagonist. Gastroenterology
106:637–642
13. Nohara H, Inoue N, Hibi T, Okita K, Hinoda Y (2003) Associ-
ation between the interleukin-1 receptor antagonist polymor-
phism and ulcerative colitis with younger age at diagnosis.
Immunol Lett 15:53–57
14. Zhang PA, Li Y, Xu P, Wu JM (2004) Polymorphisms of inter-
leukin-1B and interleukin-1 receptor antagonist genes in patients
with chronic hepatitis B. World J Gastroenterol 10:1826–1829
15. Lopez NJ, Valenzuela CY, Jara L (2009) Interleukin-1 gene
cluster polymorphisms associated with periodontal disease in
type 2 diabetes. J Periodontol 80:1590–1598
16. Wen AQ, Wang J, Feng K, Zhu PF, Wang ZG, Jiang JX (2006)
Effects of haplotypes in the interleukin 1beta promoter on lipo-
polysaccharide-induced interleukin 1beta expression. Shock
26:25–30
17. Mark LL, Haffajee AD, Socransky SS (2000) Effect of the
interleukin-1 genotype on monocyte IL-1beta expression in
subjects with adult periodontitis. J Periodontal Res 35:172–177
18. di Giovine FS, Takhsh E, Blakemore AI, Duff GW (1992) Single
base polymorphism at -511 in the human interleukin-1 beta gene
(IL1 beta). Hum Mol Genet 1:450
19. McIntyre KW, Stepan GJ, Kolinsky KD (1991) Inhibition of
interleukin 1 (IL-1) binding and bioactivity in vitro and modu-
lation of acute inflammation in vivo by IL-1 receptor antagonist
and anti-IL-1 receptor monoclonal antibody. J Exp Med
173:931–939
20. Hoffmann R, Eicheler W, Wenzel E, Happle R (1997) Inter-
leukin-1beta-induced inhibition of hair growth in vitro is medi-
ated by cyclic AMP. J Invest Dermatol 108:40–42
21. Hoffmann R (1999) The potential role of cytokines and T cells in
alopecia areata. J Investig Dermatol Symp Proc 4:235–238
22. Hoffmann R, Wenzel E, Huth A, van der Steen P, Schaufele M,
Henninger HP, Happle R (1994) Cytokine mRNA levels in Alopecia
areata before and after treatment with the contact allergen diphe-
nylcyclopropenone. J Invest Dermatol 103:530–533
23. Arend WP (2002) The balance between IL-1 and IL-1 Ra in
disease. Cytokine Growth Factor Rev 13:323–340
24. Zanardini R, Bocchio-Chiavetto L, Scassellati C et al (2003)
Association between IL-1beta -511C/T and IL-1RA (86 bp)n
repeats polymorphisms and schizophrenia. J Psychiatr Res
3:457–462
25. Chourasia D, Achyut BR, Tripathi S, Mittal B, Mittal RD,
Ghoshal UC (2009) Genotypic and functional5 roles of IL-1B and
IL-1RN on the risk of gastroesophageal reflux disease: the pres-
ence of IL-1B-511*T/IL-1RN*1 (T1) haplotype may protect
against the disease. Am J Gastroenterol 104:2704–2713
26. Blakemore TarlowJK, Cork MJ et al (1994) Interleukin-1
receptor antagonist gene polymorphism as a disease severity
factor in systemic lupus erythematosus. Arthritis Rheum 37:
1380–1385
27. Mansfeld HoldenH, Tarlow JK et al (1994) Novel genetic asso-
ciation between ulcerative colitis and the anti-inflammatory
cytokine interleukin-1 receptor antagonist. Gastroenterology
106:637–642
28. Zanardini R, Bocchio-Chiavetto L, Scassellati C et al (2003)
Association between IL-1beta -511C/T and IL-1RA (86 bp)n
repeats polymorphisms and schizophrenia. J Psychiatr Res
37:457–462
29. Pociot F, Molvig J, Wogensen L, Worsaae H, Nerup J (1992)
TaqI polymorphism in the human interleukin-1 beta (IL-1 beta)
gene correlates with IL-1 beta secretion in vitro. Eur J Clin Invest
22:396–402
30. El-Omar EM, Carrington M, Chow WH et al (2000) Interleukin-1
polymorphisms associated with increased risk of gastric cancer.
Nature 404:398–402
31. Chang YW, Jang JY, Kim NH et al (2005) Interleukin-1B (IL-
1B) polymorphisms and gastric mucosal levels of IL-1beta
cytokine in Korean patients with gastric cancer. Int J Cancer
114:465–471
32. Chen H, Wilkins LM, Aziz N et al (2006) Single nucleotide
polymorphisms in the human interleukin-1B gene affect tran-
scription according to haplotype context. Hum Mol Genet
15:519–529
33. Tarlow JK, Clay FE, Cork MJ, Blakemore AIF, McDonagh AJG,
Messenger AG, Duff GW (1994) Severity of alopecia areata is
associated with a polymorphism of the interleukin-1 receptor
antagonist gene. J Invest Dermatol 103:387–390
34. McDonagh AJ, Tazi-Ahnini R (2002) Epidemiology and genetics
of alopecia areata. Clin Exp Dermatol 27:405–409
35. Barahmani N, Lopez A, Babu D, Hernandez M, Donely SE,
Duvic M (2010) Serum T helper 1 cytokine levels are greater in
patients with alopecia areata regardless of severity or atopy. Clin
Exp Dermatol 35:409–411
36. Barahmani N, deAndrade M, Slusser J, Zhang Q, Duvic M (2002)
Interleukin-1 receptor antagonist allele 2 and familial alopecia
areata. J Invest Dermatol 118:335–337
Clin Exp Med
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