Anti‑Ku autoantibodies. Series of 5 cases

Abstract

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.

Facial nerve palsy and anti-Ku autoantibodies

“…We confirm a potential association of anti-Ku antibodies and PFNP and extend the observations of Gryga et al [6] to patients without overt connective tissue disease. PFNP may be a leading symptom in patients with high titers of anti-Ku autoantibodies.…”

“…Alternatively, they may evolve from an indirectly antibody-associated pathogenesis, as in rheumatological disorders including systemic sclerosis, Sjögren syndrome, or mixed connective tissue disease [9]. In this light and given the recent publication of Gryga et al [6], an association of anti-Ku antibodies and the recurrent PFNP of our patient seems probable. MRI revealed contrast enhancement in the distal intrameatal and the labyrinthine facial nerve segment, which is a typical feature in inflammatory peripheral facial nerve palsy [10][11][12].…”

“…PFNP may be a leading symptom in patients with high titers of anti-Ku autoantibodies. It may occur in tandem with myositis, scleroderma, osteoarticular pain, sicca syndrome, and Raynaud's phenomenon [6] or, as in our case, with limited clinical rheumatological findings. While actually not suffering from a classical connective tissue disease, our patient did however had a history of psoriasis and thus signs of a systemic autoimmune disorder.…”

“…A potential association of PFNP and anti-Ku antibodies has been postulated by Gryga et al [6] in a first report on three patients. The origin of PFNP is mostly idiopathic or infectious.…”

“…Recently, PFNP has been observed in three patients with anti-Ku antibodies and systemic autoimmune disorders [6].…”