INTRODUCTION: The interleukin 18 (IL-18) receptor complex is a heterodimer consisting of IL-18Rα and IL-18β. Both chains are required for IL-18 signaling transduction in T cells and natural killer cells.
OBJECTIVE: We aimed to determine whether polymorphisms of the IL-18Rα gene promoter were associated with susceptibility to tuberculosis in Chongqing, China.
METHODS: In 123 patients (91 children and 32 adults) with tuberculosis and 249 normal controls (167 children and 82 adults) in Chongqing, we analyzed the polymorphisms at positions -69T/C and -638T/C in the promoter of IL-18Rα by using polymerase chain reaction with sequence-specific primers.
RESULTS: Allele and genotype frequencies at position -638 of the IL-18Rα gene polymorphisms were similar in patients with tuberculosis and normal controls (P > .05). However, the frequency of -69/CC was significantly lower in patients with tuberculosis than in controls (χ2 = 8.484; P = .004 < .05). The frequency of -69/TT was significantly higher in patients with tuberculosis than in controls (χ2 = 4.027; P = .045 < .05). The frequency of allele C at position -69 in tuberculosis was significantly lower that than in controls (χ2 = 9.816; P = .002 < .05). The frequency of allele C at position -69 in patients with severe tuberculosis was significantly lower than that in patients with pulmonary tuberculosis (χ2 = 4.664; P = .031 < .05).
CONCLUSIONS: Polymorphisms of the IL-18Rα gene at position -69 were associated with susceptibility to tuberculosis in Chongqing. The people with allele C at position -69 may be protected against mycobacterium tuberculosis infection. Moreover, the position -69 of IL-18Rα may be associated with a severe degree of tuberculosis.
Submitted by Li-Ping Jiang
- Copyright © 2008 by the American Academy of Pediatrics