Background The presence of anti-Ku antibody is associated with a wide variety of clinical manifestations and various outcomes.
Objectives We attended to refine anti-Ku associated disease by identifying subgroups of Ku-positive patients with similar clinico-biological features and prognosis.
Methods We reviewed clinical, biological characteristics, diagnosis and management of 24 patients with anti-Ku antibody. A multidimensional analyze was performed to highlight homogeneous groups of patients. We search for features that most strongly match with each group.
Results Anti-Ku positive patients had joint (n=19), muscle (n=10), lung (n=9), skin (n=9), renal (n=9), hematological (n=8), thrombotic (n=6), serous (n=6) and gastrointestinal (n=4) involvements. Associated antibodies were anti-DNA (n=7), -SSA (n=6), -RNP (n=4), -SSB (n=1), -Sm (n=1), rheumatoid factor (n=9) and ACPA (n=4). Diagnosis were overlap myositis (n=9), lupus erythematosus (n=8), Sjögren's syndrome (n=7), rheumatoid arthritis (n=3), undifferentiated connective (n=2), and systemic sclerosis (n=2). Many patients had criteria for several connectivite tissue diseases. Managements were heterogeneous.
Multidimensional analyze identified to groups that were mutually exclusive: (i) Patients characterized by scleroderma-like skin disease,myositis and ILD,frequently treated with high dose of corticosteroids, (ii) Patients with lupus like skin disease, haematological and renal involvements frequently receiving cyclophosphamide and mycophenolate mofetil.
Anti-DNA antibody, absent in the first group and present in the second was the most powerful criteria to distinguish these two subsets of the anti-ku associated disease (sensibility 93% and a sensitivity of 86%).
Conclusions Anti-DNA status distinguishes patients at risk of muscle and lung involvement (anti-DNA negative) from patients at risk of renal involvement (anti-DNA positive). These data significantly refine anti-Ku associated disease and help to personalize monitoring and care of the patients.
Disclosure of Interest None declared