Urinary IL-6: a marker for mesangial proliferative glomerulonephritis?

Abstract

SUMMARYA prospective study of plasma and urinary interleukin-6 (IL-6) levels was performed in 54 patients undergoing renal biopsy to determine whether detectable urinary IL-6 was a reliable marker for mesangial proliferation, Interleukin-6 was found in both the urine and plasma of seven patients, the urine alone of 15 patients, and the plasma alone of two patients. Interleukin-6 was not detected in the urine or the plasma ofthe remaining 30 patients, the urine of 10 healthy controls or the urine of 10 patients with rheumatoid arthritis with raised plasma IL-6. Interleukin-6 was found in the urine of only one out ofan additional seven patients with lupus nephritis. Urinary IL-6 was associated with a variety of renal abnormalities and was not restricted to those with mesangial hypercellularity. Furthermore, many patients with mesangial hypercellularity did not have detectable urinary IL-6. There was no correlation between urinary IL-6 and plasma IL-6, urinary albumin excretion or urinary creatinine. These results suggest that IL-6 detected in the urine is a marker of renal IL-6 production, but not specifically of mesangial hypercellularity. The patients with IL-6 in the urine had a mean serum creatinine significantly higher than those without IL-6. It is not possible to distinguish at present whether IL-6 contributes to renal dysfunction or whether it reflects renal damage.

The weight of interleukin-6 in B cell-related autoimmune disorders

“…These findings raise the possibility that the scenario is autocrine, and the B-cell hyperactivity partly independent of T cell help. Claims have also been made [28] that urinary IL-6 is a marker for proliferative glomerulonephritis. This is not surprising, because infiltrating inflammatory cells, mainly monocytes and macrophages, could be the major source of IL-6 in the kidney of patients with lupus nephritis [29].…”

Recent Advances in Immunopathophysiology of Interleukin-6: An Innovative Therapeutic Drug, Tocilizumab (Recombinant Humanized Anti-human Interleukin-6 Receptor Antibody), Unveils The Mysterious Etiology of Immune-Mediated Inflammatory Diseases

“…43,44) Increased IL-6 has also been detected in the urine and renal glomeruli of patients with lupus nephritis. 45) NZB and NZW F1 (B/WF1) mice spontaneously develop autoimmune disease that resembles human SLE, i.e., hypergammaglobulinemia, autoantibody production including anti-DNA antibody, immune complex-mediated glomerulonephritis, and death from renal failure. We and others previously reported that B cells from BWF1 mice in vitro show hyperresponsiveness to IL-6 and then produce anti-DNA antibody.…”

Effect ofIL-6C-572G polymorphism on idiopathic membranous nephropathy risk in a han chinese population

“…10,11 Urinary IL-6 stimulates proliferation of rat mesangial cells that produce IL-6 in vitro. 10 It has also been identified as a marker of renal IL-6 production, 12 yet elevated levels of IL-6 in urine have been found in 30-50% of patients with IgA nephropathy. 10,11 IL-6 may thus act as an autocrine growth factor in the mesangium and dysregulated production of IL-6 may be involved in the mesangial proliferation associated with glomerulonephritis.…”