Anti-Ku autoantibodies: series of 5 cases.

Autoantibodies directed against nuclear protein Ku are infrequently detected. If present, they are found in high titers in patients with connective tissue overlap syndromes. This article describes 5 patients with anti-Ku antibodies in whom systemic lupus erythematosus, Sjögren's syndrome, idiopathic lung fibrosis or scleroderma - polymyositis overlap syndrome were diagnosed. Interestingly, signs and symptoms of transient cranial neuropathy involving trigeminal and facial nerves were reported by 3 patients. Cranial nerve neuropathy has not been described in patients with anti-Ku autoantibodies previously.