A spectrum of clinicopathological features of nephropathy associated with POEMS syndrome.

Abstract

In POEMS syndrome, substantial involvement of the kidney can occur and is reflected by proteinuria, haematuria, renal dysfunction, and renal failure requiring dialysis therapy. The mechanism by which renal dysfunction is induced and progresses to end-stage renal disease remains obscure. A pathogenic role of cytokines and growth factors has recently been implicated. We reviewed cases of 52 Japanese patients with confirmed renal pathology who were reported in the literature, and personally analysed renal tissues from 22 subjects including nine patients of our own. Interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) were measured in our cases. Despite relatively mild renal symptomatology, about half of the cases had azotaemia with creatinine levels above 1.5 mg/dl and the BUN/creatinine ratio markedly raised by volume contraction or wasting. One-tenth of patients were placed on haemodialysis because of advanced or end-stage renal disease. Bilateral and unilateral contracted kidneys were found in four and two cases respectively. Pathological analyses disclosed two major changes: glomerular alterations and endarteritis-like lesions of renal small arteries. The former included glomerular enlargement, cellular proliferation, mesangiolysis and marked swelling of endothelial-mesangial cells. This structural disorganization led to a reduction in renal function to some degree by impairing the glomerular circulation. Vasculopathy of the small artery probably resulted in progressive renal damage and ultimately to kidney contraction. Serum IL-6 was elevated in about 40% of cases. IL-6 levels were found to be high in the ascites of three patients who were examined. In different studies, an increased level of VEGF was found in the peripheral blood (75-100%; overall 92.3%), but no apparent correlation with glomerular alterations was observed. POEMS nephropathy can be one cause of end-stage renal disease with variable intrarenal pathological changes of a microangiopathic nature which have differential influences on renal function. A pathogenic role for VEGF in POEMS syndrome appears to be likely, but its causal relation to the nephropathy awaits further investigation.