Proteomics characterization of CENP-B epitope in Moroccan scleroderma patients with anti-centromere autoantibodies.

BACKGROUND: Anti-centromere auto-antibodies (ACA) have been described as a marker in Systemic sclerosis (SSc) disease. CENP-B is the major centromere auto-antigen recognized by SSc patients with positive ACA. Our aim was to characterize the major epitope involved in the anti-CENP-B immune response of Moroccan SSc patients.

PATIENTS AND METHOD: For identification of SSc biomarkers, 80 sera from patients with SSc and systemic lupus erythematosus (SLE) were screened by indirect immunofluorescence test (IIF) to assess the presence of ANA reactivity. Immunoblotting analysis was performed for 11 sera with positive ACA using the N-terminal and C-terminal region of CENP-B protein as antigens.

RESULTS: 29 out of 30 (96, 66 %) patients with SSc had positive ANA. 11 out of 30 (36, 67 %) patients were ACA positive and 6 of them produced auto-antibodies against Nt-CENPB antigen. Two of these 6 Nt-CENPB positive sera produced also other auto-antibodies associated to primary biliary cirrhosis. None of all sera tested showed reactivity against Ct-CENPB.

CONCLUSION: Our data showed, for the first time in Morocco, that the Nt-CENPB contains a major epitope for Moroccan SSc patients. These findings could provide additional information that would contribute to improving the diagnosis and management of these patients.