A 54-year-old woman with recurrent episodes of bilateral knee arthritis was admitted several times to the Department of Rheumatology. She was diagnosed to have chronic calcium pyrophosphate crystal arthritis. Interleukin 1β (IL-1β) plays a central role in the pathogenesis of inflammation induced by calcium pyrophosphate crystals, and IL-1β blockade may be an effective treatment in patients with severe chronic calcium pyrophosphate crystal arthritis. Because of the short effect of treatment with corticosteroids and the frequent attacks of arthritis, the patient was treated with the IL-1 receptor antagonist anakinra. She responded well after 1 week with normalization of inflammation. Eight months after the initiation of treatment, the patient has had no relapses, although we were unable to withdraw the anakinra.

The standard incidence ratio of cancer following iv CYC was increased, although not statistically significantly. No urinary bladder cancer or haemorrhagic cystitis developed even though mesna prophylaxis was not given.