title: Interleukin-18 gene polymorphisms in Egyptian patients with allergic diseases.
abstract: BACKGROUND
  Allergic diseases, such as allergic rhinitis (AR) and atopic dermatitis (AD), affect a large proportion of people worldwide. Both have environmental and genetic predisposing factors. Single nucleotide polymorphisms (SNPs) in interleukin (IL)-18, may play a direct  role in the disease pathogenesis. This study was designed to investigate the association of the IL-18 gene SNPs (-137 G/C [rs187238], and -140 C/G [rs360721]) with AR and AD, as well as their relations to the diseases' severity.
  
  
  METHODS
  Seventy-five  individuals were enrolled in the study including, 25 AD children, 25 AR patients, and 25 unrelated healthy adult volunteers who served as controls. Genotyping was performed by polymerase chain reaction and restriction fragment length polymorphism analysis.
  
  
  RESULTS
  AR and  AD patients showed no significant differences in the genotype distribution and allele frequencies of -137 G/C and -140 C/G SNPs when compared independently with the control group. However, the -140 GG genotype and the -140 G allele were more often associated with severe  AD compared with mild and moderate phenotypes (p = 0.01 and 0.001, respectively; odds ratios [ORs], 14.25 [95% CI, 1.48-143.2] and 16 [95% CI, 2.8-90.46], respectively). Moreover, the -137 G allele was associated with moderate/severe AR (p = 0.019; OR, 6.1 [95% CI, 1.34-28.1]).
  
  
  CONCLUSIONS
  This preliminary study indicates that the studied polymorphisms do not confer susceptibility to allergy in Egyptian patients but may be related to the disease phenotype. However, the role of IL-18 in allergy may be too complex to be reflected in a simple association  study.
authors: Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia, Egypt. Gehan_amer@med.suez.edu.eg
authors: Gehan H
authors: GH
authors: Ibrahim
authors: Mohammed T
authors: MT
authors: ElTabbakh
authors: Amal H A
authors: AH
authors: Gomaa
authors: Eman A
authors: EA
authors: Mohamed
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000235:genetics* / Q000276:immunology; D018450:Disease Progression; D004534:Egypt; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D020382:Interleukin-18 / Q000235:genetics*; D008297:Male; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D012221:Rhinitis, Allergic, Perennial / Q000235:genetics* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000235:genetics* / Q000276:immunology; D055815:Young Adult
chemical_list: D020382:Interleukin-18