Interleukin 8 gene 2767 A/G polymorphism is associated with increased risk of nephritis in children with Henoch–Schönlein purpura

The objective of this study is to investigate the association between IL-8 gene 2767 G/A polymorphism and clinical features, kidney involvement and prognosis in childhood Henoch Schnölein purpura (HSP). A total of 115 patients with HSP (59 male, 56 female) were included in the study with age at diagnosis between 2 and 17 years (8.0 ± 3.0). Hundred and eight healthy adults were included in the study as controls. The patients had been followed up for kidney involvement for at least 6 months and in average 8.2 ± 7.5 months. Interleukin 8 (IL–8) gene 2767 G/A polymorphism was studied by PCR–RFLP method. Frequency of the “A” allele was 0.37 in the patient group, whereas it was 0.36 in the control group. The difference was not statistically significant (P = 0.696). No association was detected between the IL-8 gene G/A polymorphism and the clinical, laboratory, and demographic data related to the patients with HSP. Kidney involvement was more common in those with the G/A polymorphism of the IL-8 gene. While a 0.44 frequency of the “A” allele was detected in those with kidney involvement, this rate was 0.29 in those with no kidney involvement (P = 0.046). Follow-up of those with the “A” allele revealed higher proteinuria (P = 0.023, odds ratio 0.176, 95% CI 0.034–0.917) and higher creatinine levels (P = 0.049, odds ratio 0.024, 95% CI 0.036–0.094). These results suggest that the kidney involvement is more common in patients with the “A” allele, and degree of proteinuria and creatinine levels is higher in these patients at follow-up.