Interleukin-6 receptor inhibition with tocilizumab in various renal involvements associated with multicentric Castleman's disease: a report of three cases.

Multicentric Castleman's disease (MCD) is an inflammatory lymphoproliferative disorder characterized by polyclonal hypergammopathy and dysregulated overproduction of interleukin-6 (IL-6). A variety of renal involvements infrequently arise in patients with MCD. However, there is no established treatment for MCD and its associated renal involvements. We present the effects of an anti-IL-6 receptor monoclonal antibody, tocilizumab, on three patients with MCD associated with various renal manifestations. In all three patients, tocilizumab treatment was very effective in reducing proteinuria and stabilizing renal function, as well as improving other clinical symptoms. These findings indicate the pathological significance of IL-6 in renal involvements associated with MCD, and the potential use of tocilizumab in its treatment.