For FCAS / MWS, biochemical and clinical correlates of autoinflammatory disease will be measured at baseline following withdrawal of currently used IL-1 inhibitors. Subjects will receive a course of therapy with XOMA 052 that is predicted to provide an estimated 4 weeks of anti-inflammatory activity. If a favorable response is obtained, the continuation phase will last twelve months. For BD, subjects will receive XOMA 052 for three to six months and patients with a positive response will then be randomized to withdrawal or continuation of drug for six months. Clinical and biochemical correlates of inflammation will be measured in both patient groups at appropriate intervals to assess response and to further elucidate disease mechanisms.