Interleukin 1 Receptor Antagonist(IL-1ra) Gene Polymorphism in Children with Henoch-Schönlein Purpura Nephritis

Hwang, Phil-Kyung; Lee, Jeong-Nye; Chung, Woo-Yeong

J Korean Soc Pediatr Nephrol > Volume 9(2); 2005 > Article

J Korean Soc Pediatr Nephrol 2005;9(2): 175-182.

Henoch-Schönlein Purpura 신염에서 Interleukin 1 Receptor Antagonist(IL-1ra) 유전자 다형성

황필경, 이정녀, 정우영

¹인제대학교 의과대학 소아과학교실
²인제대학교 의과대학 진단검사의학교실
³인제대학교 의과대학 소아과학교실

Interleukin 1 Receptor Antagonist(IL-1ra) Gene Polymorphism in Children with Henoch-Schönlein Purpura Nephritis

Phil-Kyung Hwang, Jeong-Nye Lee, Woo-Yeong Chung

¹Departments of Pediatrics, Inje University, College of Medicine, Busan Paik Hospital
²Laboratory Medicine, Inje University, College of Medicine, Busan Paik Hospital
³Departments of Pediatrics, Inje University, College of Medicine, Busan Paik Hospital

ABSTRACT

Purpose : Interleukin 1 receptor antagonist(IL-1ra) is an endogenous antiinflammatory agent that binds to IL-1 receptor and thus competitively inhibits the binding of IL-1$alpha$ and IL-1$beta$. Allele 2 in association with various autoimmune diseases has been reported. In order to evaluate the influence of IL-1ra gene VNTR polymorphism on the susceptibility to HSP and its possible association with disease severity, manifested by severe renal involvement and renal sequelae, we studied the incidence of carriage rate and allele frequency of the 2 repeats of IL-1ra allele 2($IL1RN^{*}2$) of the IL-1ra gene in children with HSP with and without renal involvement.
Methods : The IL-1ra gene polymorphisms were determined in children with HSP with(n=40) or without nephritis(n=34) who had been diagnosed at Busan Paik Hospital and the control groups(n=163). Gene polymorphism was identified by PCR amplification of the genomic DNA.
Results : The allelic frequency and carriage rate of $IL1RN^{*}1$ were found most frequently in patients with HSP and in controls. The allelic frequency of $IL1RN^{*}2$ was higher in patients with HSP compared to that of controls($4.7%;vs.;2.5%$, P=0.794). The carriage rate of $IL1RN^{*}2$ was higher In patients with HSP compared to that of controls($8.1%;vs.;6.8%$, P=0.916). The allelic frequency of $IL1RN^{*}2$ was higher in patients with HSP nephritis compared to that of HSP($5.3%;vs.;2.9%$, P=0.356). The carriage rate of $IL1RN^{*}2$ was higher in Patients with HSP nephritis compared to that of HSP($10.0%;vs.;5.9%$, P=0.523). Among 13 patients with heavy proteinuria(>1.0 g), 11 had $IL1RN^{*}1$, 1 had $IL1RN^{*}2$ and the others had $IL1RN^{*}4$. At the time of last follow up 4 patients had sustained proteinuria and their genotype was $IL1RN^{*}1$.
Conclusion : The allelic frequency and carriage rate of $IL1RN^{*}1$ were found most frequently in patients with HSP and in controls. Our study suggests that the carriage rate and allele frequency of the 2-repeats of IL-1lra allele 2($IL1RN^{*}2$) of the IL-1ra gene may not be associated with susceptibility and severity of renal involvement in children with HSP (J Korean Soc Pediatr Nephrol 2005;9:175-182)

Key words: IL-1ra gene polymorphism | Allele frequency | Carriage rate