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.