ABSTRACTWe report a 53-year-old man who presented with acute renal failure. His medical history revealed a spondyloarthropathy, for which secukinumab was started recently, and a monoclonal gammopathy of unknown significance. Kidney function deteriorated despite the withdrawal of secukinumab and dialysis was started. In the serum, type 1 cryoglobulins were present and a kidney biopsy showed ischaemic glomeruli, with thrombosis of the larger interlobular arteries. Other causes of thrombotic microangiopathy were excluded. Bone marrow immunophenotyping showed 1% monoclonal plasma cells. A diagnosis of monoclonal gammopathy of renal significance was made. Haematological treatment resulted in haematological and renal response.