Objective: To look for anti-CENP-B antibodies and their diagnostic relevance in patients negative and positive for anticentromere antibodies (ACA) with different risk for the development of systemic sclerosis (SSc), including uranium miners exposed to quartz dust.
Methods: We studied sera of 107 patients with SSc, 121 patients with possible SSc, 202 uranium miners heavily exposed to quartz dust, 14 patients with vibration induced white fingers, and 240 control patients. Subjects were screened for ACA by indirect immunofluorescence on HEp-2 cells (IIF-ACA) and then for anti-CENP-B autoantibodies by an ELISA using eukaryotically expressed human full length recombinant CENP-B protein.
Results: All IIF-ACA positive sera of "idiopathic" SSc (N = 19), "idiopathic possible" SSc (N = 6) and other patients (N = 11), and 17 of 19 IIF-ACA positive sera of miners exposed to silica with (N = 13) and without (N = 6) symptoms of SSc reacted with CENP-B in this assay. Of the 622 IIF-ACA negative sera, 28 were found positive for anti-CENP-B. There was a significant increase of the prevalence of anti-CENP-B antibodies in IIF-ACA negative patients with possible SSc (11 of 109) and in miners exposed to silica (11 of 196) compared to a group of men older than 60 years with diseases or symptoms not related to SSc (1 of 138).
Conclusion: (1) CENP-B is also the major target of the IIF-ACA response in diseases other than scleroderma and in the risk group of miners exposed to quartz dust. (2) Anti-CENP-B antibodies can be found in IIF-ACA-negative sera, particularly in those at risk for SSc. (3) The detection of anti-CENP-B antibodies in miners exposed to quartz dust may indicate a high risk group for developing SSc and reveals possibilities for the study of early pathogenetic changes as well as exogenic and endogenic factors involved in the development of this disease.