Interleukin-4 Gene Polymorphism in Kuwaiti Children with Idiopathic Nephrotic Syndrome

Background: Idiopathic Nephrotic syndrome (INS) is an immune-mediated disease with a well-documented association with atopy. IL-4 is a vital cytokine involved in atopic symptoms Gene polymorphism of IL-4 controls the expression and function of IL-4 and therefore might have an effect on the pattern of INS.

Objective : To determine the frequency and the association of IL-4 gene polymorphisms with INS and its effect on the disease pattern in Kuwaiti children with INS.

Methods: Genotypes of the IL-4 gene polymorphisms were analyzed using PCR-RFLP in 151 INS patients and 59 age and sex- matched controls. Clinical data of all subjects were reviewed.

Results: A total of 151 INS (129 steroid-sensitive and 22 steroid- resistant) patients with a mean age was 7.6±4.3 years were studied. Male: Female ratio was 2:1. The CC genotype of IL-4 gene polymorphism was detected in 64% of the INS patients compared to 69.5% of the controls (P=0.57). The heterozygous CT genotype was detected in 30% of INS patients compared 25.5% of the controls (P =0.61). The TT-genotype was detected in 6% of INS patients and 5% of the controls (P =1.00). The C-allele frequency in homozygous and heterozygous forms was found in 94% of INS patients compared to 95% of the controls (P =1.00). The T-allele frequency in homozygous and heterozygous forms was found in 35.7% of INS patients compared to 30.5% of the controls (P =0.57). No significant difference was found in any of the allele frequencies between SS and SR sub-groups when compared with each other or when compared to the controls.

Conclusion: Our data shows no role of IL-4 gene polymorphisms on the clinical pattern or response to steroids in Kuwaiti children with INS.