Response to anti-TNF-α treatment for secondary renal amyloidosis in a patient with ankylosing spondylitis

Renal amyloidosis is a complication of ankylosing spondylitis. A possible pathogenetic role is due to TNF-α, with a direct action on glomerular receptors TNFR2 and renal injury, secondary to deposition of amyloid fibrils. The most frequent clinical manifestation is proteinuria or nephrotic syndrome. Etanercept, a soluble receptor of TNF-α, binds this circulant cytokine with a progressive improvement of renal function and reduction of deposits of amyloid. Transient leukopenia, observed during ankylosing spondylitis, should not be considered a controindication to the use of Etanercept, but it requires a constant monitoring. The benefit observed in our patient can represent an indication to the use of Etanercept for the management of amyloidosis.