Serum cytokine profile in reflux nephropathy

Abstract

Cytokines are small regulatory peptides with diverse functions. They regulate the immune system and modulate the inflammatory response, both of which are implicated in vesico-ureteric reflux (VUR) and associated reflux nephropathy (RN). The cytokine profile in VUR and RN has yet to be fully investigated. Blood was obtained from three subject groups immediately after induction of anaesthesia: group A [subjects with VUR and established RN, (N=9)]; group B [VUR alone but no associated RN, (N=6)]; and group C [age- and sex-matched controls with no history of urinary sepsis, (N=14)]. Serum cytokine levels of tumour-necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), soluble TNF receptor-1 (sTNF-R1), and interleukin-8 (IL-8) were measured using standard ELISA technique. Serum levels of IL-6 were higher in group A subjects (1.798–4.638 pg/ml, median 3.253 pg/ml) than controls (1.531–2.078 pg/ml, median 1.798 pg/ml). There was no significant difference in levels in group B subjects (1.498–3.048 pg/ml, median 1.948 pg/ml) and controls. These same relationships were observed for levels of TNF-α (group A: 8.501–14.471 pg/ml, median 13.483 pg/ml; group B: 7.088–10.650 pg/ml, median 8.886 pg/ml; group C: 6.746–13.344 pg/ml, median 7.671 pg/ml) and sTNF-R1 (group A: 690.34–5780.74 pg/ml, median 1197.38 pg/ml; group B: 366.65–1401.62 pg/ml, median 592.82 pg/ml; C: 313.49–636.33 pg/ml, median 504.17 pg/ml). IL-8 was not significantly elevated in any of the study groups (A or B) compared with control group C (group A: 27.08–56.38 pg/ml, median 31.35 pg/ml; group B: 29.90–35.87 pg/ml, median 31.35 pg/ml; group C: 25.05–30.22 pg/ml, median 29.90 pg/ml). These results suggest there may be an immunological basis to RN.