A case of POEMS syndrome showing elevated serum interleukin 6 and abnormal expression of interleukin 6 in the kidney

A 46-year-old female presented with POEMS syndrome. Hemodialysis was initiated to control severe anasarca and declining renal function. Corticosteroids were effective in treating renal insufficiency and other symptoms. Serum interleukin 6 (IL-6) was elevated before the corticosteroid therapy but returned to the normal level under the therapy. Immunostaining for the kidney tissue obtained by a renal biopsy showed a diffuse distribution of IL-6 in the glomeruli; thus, in contrast to normal, IL-6 was detected not only in mesangial cells but also in endothelial cells. IL-6 was also distributed in capillaries in the interstitium. While these results suggest a pathogenic role of IL-6 in POEMS syndrome, other factors may be necessary for the full expression of symptoms. Furthermore, it is suggested that chronically stimulated glomerular endothelial cells are capable of producing IL-6.