Anti-Ku Antibodies in a Patient With a Polymyositis-Systemic Sclerosis Overlap Syndrome in Association With Autoimmune Hepatitis

Overlap syndromes are well-described but rare clinical entities characterized by the co-presence of two or more connective tissue diseases. The combination of systemic sclerosis and polymyositis overlapping with autoimmune hepatitis (AIH) is particularly rare, as discussed in this case report. A 76-year-old woman with a recent history of pleuro-pericarditis presented with painful Raynaud’s phenomenon, lethargy, jaundice, myalgias, and weight loss. Blood tests revealed a positive antinuclear antibody and anti-Ku antibody and raised creatine kinase, together with evidence of myositis and interstitial lung disease on imaging, leading to a diagnosis of polymyositis-systemic sclerosis overlap syndrome. Raised liver transaminases, immunological tests, and liver biopsy were consistent with AIH. She was managed with corticosteroids and mycophenolate mofetil. This is only the second instance in which AIH has been reported in the context of a positive anti-Ku antibody. We discussed the complex and rare nature of this condition and the various aspects of its management.