An IL-6 level in the serum and urine in estimation of cryoglobulinemic vasculitis activity in patients with chronic hepatitis C associated with renal damage

Abstract

Aim. To estimate serum and urine IL-6 levels and to study its role in diagnosis of nephritis activity in patients with cryoglobulinemic glomerulonephritis (CGN) associated with chronic hepatitis C (CHC). Material and methods. Enzyme immunoassay was used to assay IL-6 in blood serum of 124 patients having different stages of CHC. IL-6 was also estimated in the urine of 57 patients with CHC systemic manifestations including renal damage. Results. Abnormal serum IL-6 level was seen in 36% CHC patients. Patients with elevated level of IL-6 in the serum vs patients with normal IL-6 level had cryoglobulinemia (CGE) (56% vs 26%, p < 0.01) and related systemic manifestations including cryoglobulinemic glomerulonephritis (30% vs 9%, p < 0.01). Most of (90%) patients with CHC-associated CGN had urinary IL-6 excretion correlating with severity of renal damage: the highest urinary level of IL-6 was seen in development of acute nephritic and nephritic syndromes (from 83.5 to 250 pg/ml). It did not correlate with IL-6 in the serum and proteinuria. This is evidence that IL-6 in the urine had a local origin (intrarenal), reflecting activity of immune inflammation in the kidney. Conclusion. Control of IL-6 levels in the blood serum and urine of patients suffering from CHC with cryoglobulinemic syndrome and renal damage can be used for monitoring of the disease activity.

Keywords

• chronic hepatitis c
• il-6
• glomerulonephritis
• cryoglobulinemia