Autoantibody status fails to predict death risk in systemic sclerosis with PAH

By Lucy Piper, Senior medwireNews Reporter

Anticentromere and isolated nucleolar autoantibodies are prevalent in systemic sclerosis (SSc) patients with pulmonary arterial hypertension (PAH), but they do not predict survival, US research shows.

“Our data demonstrate that although antibodies are associated with PAH development and time to PAH diagnosis, none of the SSc-specific serum autoantibodies were predictive of mortality”, report Monique Hinchcliff (Northwestern University Feinberg School of Medicine, Chicago, Illinois) and colleagues.

The team identified 162 patients, enrolled in the Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) registry, who had definite World Health Organization Group 1 PAH diagnosed by right heart catheterisation.

Autoantibody profiles showed the presence of anticentromere autoantibodies in 60 (37%) patients, antinuclear antibodies with an isolated nucleolar pattern in 39 (24%) patients and anti-topoisomerase 1 (Scl-70) in 11 (7%) patients. In addition, other non-specific positive antinuclear antibodies were detected in 28 (17%) patients, anti-RNA polymerase III (RNA pol) in nine (6%) patients and anti-U1RNP in eight (5%) patients while seven (4%) patients tested negative for antibodies.

Over a median follow-up of 2.1 years, 32 (20%) of the study participants died. The 1- and 3-year survival rates for the whole group were 94% and 78%, respectively. The survival rates were comparable across the various autoantibody groups, ranging from a respective 89% and 63% for patients testing positive for Scl-70 to 100% and 100% for both those with RNA pol and no antibodies.

Kaplan–Meier survival analyses showed no significant survival differences when comparing the autoantibody groups nor between patients with and without each of the different autoantibodies.

SSc disease duration differed significantly between patients testing positive for anticentromere autoantibodies and antinuclear antibodies with an isolated nucleolar pattern, at an average of 18.8 months versus 12.2 months, respectively. But even after controlling for this there was no association between autoantibody status and survival.

“[O]ur data highlight the need for identification of biomarkers that can predict which patients with SSc-PAH are at highest risk of death”, the researchers report in Seminars in Arthritis and Rheumatism.

“Unfortunately, although commercially available autoantibodies do seem to predict the development of PAH, they do not predict survival difference in SSc patients with incident PAH in our cohort.”

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