The Clinical Relevance of Antifibrillarin (anti-U3-RNP) Autoantibodies in Systemic Sclerosis

Objectives Systemic sclerosis (SSc) is a heterogeneous autoimmune disease associated with several antinuclear autoantibodies useful to diagnosis and prognosis. The aim of the present multicentric study was to determine the clinical relevance of anti-fibrillarin autoantibodies (AFA) in patients with SSc. Methods The clinical features of 37 SSc patients positive for AFA (AFA+) and 139 SSc patients without AFA (AFA-) were collected retrospectively from medical records to enable a comparison between AFA- and AFA+ patients. Anti-fibrillarin autoantibodies were screened by an indirect immunofluorescence technique using HEp2 cells and identified by an in-house Western blot technique and/or an EliA test. Results Comparing AFA+ and AFA– patients, AFA+ patients were significantly younger at disease onset (36.9 vs. 42.9; p=0.02), more frequently male (p=0.02) and of Afro-Caribbean descent (65% vs. 7.7%; p