OBJECTIVES: To determine the prevalence of anti-Ku antibodies in 625 patients with systemic sclerosis (SSc) from six European rheumatological centres and to evaluate their clinical and serological characteristics. METHODS: Sera of 625 consecutive patients with either limited cutaneous or diffuse cutaneous SSc were tested for antibodies to Ku antigen together with other extractable nuclear antigens by counterimmunoelectrophoresis. A case-control design with calculation of bootstrap 95% confidence intervals derived from anti-Ku negative control patients was used to evaluate clinical associations of anti-Ku antibodies. Sera from anti-Ku positive patients with SSc and a control group were additionally tested by immunofluorescence on Hep-2 cell substrates and line immunoassay. RESULTS: Anti-Ku antibodies were found in the sera of 14/625 (2.2%) patients with SSc. Of 14 anti-Ku positive patients with SSc, 10 had no other anti-extractable nuclear antigen (ENA) antibodies detected by counterimmunoelectrophoresis. Using a case-control study design, anti-Ku antibodies were significantly associated with musculoskeletal manifestations such as clinical markers of myositis, arthritis and joint contractures. In addition, a significant negative correlation of anti-Ku antibodies was found with vascular manifestation such as fingertip ulcers and teleangiectasias. There was a striking absence of anti-centromere antibodies as well as anti- polymyositis (PM)/scleroderma (Scl) antibodies in patients that were anti-Ku positive. As expected, anti-Scl70 and punctate nucleolar immunofluorescence patterns were present only in single cases. CONCLUSION: This is the largest cohort to date focusing on the prevalence of anti-Ku antibodies in patients with SSc. The case-control approach was able to demonstrate a clinically distinct subset of anti-Ku positive patients with SSc with only relative clinical differences in skeletal features. However, the notable exceptions were signs of myositis. This shows the importance of anti-Ku antibody detection for the prediction of this specific clinical subset.
OBJECTIVES: To determine the prevalence of anti-Ku antibodies in 625 patients with systemic sclerosis (SSc) from six European rheumatological centres and to evaluate their clinical and serological characteristics. METHODS: Sera of 625 consecutive patients with either limited cutaneous or diffuse cutaneous SSc were tested for antibodies to Ku antigen together with other extractable nuclear antigens by counterimmunoelectrophoresis. A case-control design with calculation of bootstrap 95% confidence intervals derived from anti-Ku negative control patients was used to evaluate clinical associations of anti-Ku antibodies. Sera from anti-Ku positive patients with SSc and a control group were additionally tested by immunofluorescence on Hep-2 cell substrates and line immunoassay. RESULTS: Anti-Ku antibodies were found in the sera of 14/625 (2.2%) patients with SSc. Of 14 anti-Ku positive patients with SSc, 10 had no other anti-extractable nuclear antigen (ENA) antibodies detected by counterimmunoelectrophoresis. Using a case-control study design, anti-Ku antibodies were significantly associated with musculoskeletal manifestations such as clinical markers of myositis, arthritis and joint contractures. In addition, a significant negative correlation of anti-Ku antibodies was found with vascular manifestation such as fingertip ulcers and teleangiectasias. There was a striking absence of anti-centromere antibodies as well as anti- polymyositis (PM)/scleroderma (Scl) antibodies in patients that were anti-Ku positive. As expected, anti-Scl70 and punctate nucleolar immunofluorescence patterns were present only in single cases. CONCLUSION: This is the largest cohort to date focusing on the prevalence of anti-Ku antibodies in patients with SSc. The case-control approach was able to demonstrate a clinically distinct subset of anti-Ku positive patients with SSc with only relative clinical differences in skeletal features. However, the notable exceptions were signs of myositis. This shows the importance of anti-Ku antibody detection for the prediction of this specific clinical subset.
Authors: M Aringer; U Müller-Ladner; H Burkhardt; J H W Distler; O Distler; W B Graninger; C Günther; N Hunzelmann; H Kiener; M Sticherling; C Sunderkötter; U A Walker; G Riemekasten Journal: Z Rheumatol Date: 2015-03 Impact factor: 1.372
Authors: Ulrich A Walker; Philip J Clements; Yannick Allanore; Oliver Distler; Chester V Oddis; Dinesh Khanna; Daniel E Furst Journal: Rheumatology (Oxford) Date: 2017-09-01 Impact factor: 7.580