The heterogeneity of anticentromere antibodies in immunoblotting analysis. We tested anticentromere antibody positive sera from 37 patients by immunoblotting techniques. Three antigenic polypeptides were recognized when immunoblotted against protein extracts from HeLa cell nuclei or from chromosomal segments enriched with centromere region. These were a 17 kDa (CENP-A recognized by 34 sera), an 80 kDa (CENP-B recognized by 33 sera), and a 140 kDa polypeptide (CENP-C recognized by 26 sera). There was no disease specific pattern of antigenic polypeptides, although Raynaud's phenomenon was frequent in patients with anti-CENP-B reactivities (p less than 0.01). The heterogeneity of the anticentromere antibody response in Japanese patients shows anticentromere antibody may not be a disease specific autoantibody and diagnostic marker. 