Biological Role, Mechanism of Action and the Importance of Interleukins in Kidney Diseases

Each year, the number of patients who are diagnosed with kidney disease too late is increasing, which leads to permanent renal failure. This growing problem affects people of every age, sex and origin, and its full etiopathogenesis is not fully understood, although the involvement of genetic susceptibility, infections, immune disorders or high blood pressure is suggested. Difficulties in making a correct and quick diagnosis are caused by the lack of research on early molecular markers, as well as educational and preventive activities among the public, which leads to the late detection of kidney diseases. An important role in the homeostasis and disease progression, including kidney diseases, is attributed to interleukins, which perform several biological functions and interact with other cells and tissues of the body. The aim of this article was to systematize the knowledge about the biological functions performed by interleukins in humans and their involvement in kidney diseases development. In our work, we took into account the role of interleukins in acute and chronic kidney disease and kidney transplantation.

Tumor necrosis factor alpha gene polymorphisms and haplotypes in Egyptian children with nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) characterized by complex pathogenesis and clinical course with relapses; and needs novel breakthroughs for decades. Polymorphisms of cytokines genes including tumor necrosis factor alpha (TNF-α)may influence susceptibility to NS as well as different patients' steroid responses. In the current study, we demonstrated the potential roles of TNF-α promoter gene polymorphisms [-238, -308, -863] and haplotypes in susceptibility to childhood NS. Also, elucidating their possible influence on patients' steroid response and serum TNF-α level.

METHODS

This case-control study included 150 children suffering from NS and 150 healthy children. Polymerase chain reaction- restriction-fragment length polymorphism (PCR-RFLP) was performed to evaluate different TNF-α gene polymorphism. TNF-α serum levels were assessed by ELISA.

RESULTS

Serum TNF-α levels were significantly higher in NS patients than in controls and in steroid resistant NS (SRNS) than in steroid sensitive NS (SSNS) (P<0.001 for each). The risk of NS in patients carrying TNF-α-238GA genotype, and TNF-α-308GA or AA genotypes and allele A was significantly increased compared to healthy children. While no significant association was detected between TNF-α-863 and NS. The risk of resistance to steroid therapy was significantly high in NS carrying TNF-α-238GA genotype and A allele, TNF-α-308, AA genotypes and A allele, and TNF-α-863CA, AA genotypes and A allele. The TNF-α GCG (-308/-863/-238) haplotype has protective roles against NS and steroid resistance. However, the risk of NS was significantly high in TNF-α AAG and AAA haplotype's carriers compared to healthy children. Additionally the risk of steroid resistance was significantly high in TNF-α AAA haplotype's NS carrier (OR (95%CI): 2.2 (1.19-4.36), P=0.01). Moreover, we found significant higher serum TNF-α levels NS patients including SSNS and SRNS carrying mutant allele TNF-α-238GA genotype, -308GA and AA and -863CA and AA wild genotype's carriers than in those GG, GG and CC respectively. Interstingely, TNF-α levels were significantly higher in healthy children carrying TNF-α(-308/-863/-238) [AAG and AAA haplotypes], NS cases carrying [ACA, AAG, AAA haplotypes], and in SSNS carrying [ACA and AAA haplotypes] than in those carrying GCG, haplotype of wild alleles.

CONCLUSION

This study reported, for the first time, that TNF-α promoter gene polymorphisms and/or haplotypes are risk factors of NS and resistance to steroid among Egyptian children.