Commonly found in patients with limited cutaneous SSc, and as such included in the classification criteria for SSc.

In combination with Raynaud phenomenon, the AC-3 pattern is prognostic for onset of limited cutaneous SSc.

Strongly associated with antibodies to CENP-B; especially in case of low titers, confirmation by an antigen-specific immunoassay is recommended to support the association with limited cutaneous SSc; the CENP-B antigen is included in many routine ENA profiles.

The AC-3 pattern is also apparent in a subset of patients with PBC; these patients often have both SSc as well as PBC.

The AC-3 pattern is found in a subset of patients with SjS; these patients show mild SSc features, but a full-blown SjS clinical feature, more severe exocrine glandular dysfunction, and high risk of lymphoma.

The AC-3 pattern is also apparent in a subset of patients with SLE; these patients often have some degree of overlap with SSc.

Most sera with the AC-3 pattern react with CENP-A and CENP-B; antibodies to CENP-A can be detected by ELISA or disease specific immunoassays (i.e., SSc profile).

In rare cases AC-3 positive, but CENP-B negative sera of SSc patients may be strongly positive for anti-CENP-A antibodies.

Antibodies to CENP-C have been reported in patients with SSc and SjS.

Availability of assays for CENP-A, i.e., ELISA or SSc profile, may be limited to specialty clinical laboratories; specific immunoassays for anti-CENP-C antibodies are currently not commercially available.