Evaluation of anti-CENP reactivity in samples with centromere HEp-2 pattern and correlation with Systemic Sclerosis clinical features

Abstract

AbstractBackground/ObjectivesAnti-centromere antibodies are associated with limited cutaneous Systemic Sclerosis (lcSSc) and in general, with a more favorable prognosis for SSc. Centromere pattern (AC-3) observed in the immunofluorescence assay in HEp-2 cells (HEp-2-IFA) suggests the presence of antibodies against CENP antigens, mainly CENP-B/A. In this study, we evaluated the frequency of reactivity to CENP-B and CENP-A in samples with an AC-3 pattern in the HEp-2-IFA. We also correlated the demographic and clinical characteristics of SSc patients according to the presence of the AC-3 pattern.MethodsSamples from 39 SSc patients with AC-3 pattern were included and evaluated for CENP-B/A reactivity by line-blot and indirect ELISA. As controls, 48 lcSSc without the AC-3 pattern (Non-AC-3 group) were included. Clinical characteristics were recovered for 69 patients, 21 with AC-3 and all those in the Non-AC-3 group.ResultsOut of 39 samples with AC-3, 33 (84.6%) were reactive against CENP-B and 32 (82.1%) were reactive against CENP-A using the line-blot assay. Using anti-CENP-B ELISA, 36 (92.3%) of the samples with AC-3 were positive for anti-CENP-B. There was 79.5% concordance for CENP-B reactivity between ELISA and line-blot. Using the immunoblot assay, 27 (69.2%) of the samples with AC-3 were reactive against CENP-B and CENP-A, and one sample was positive only for CENP-A. Altogether, 38 samples (97.4%) were reactive against CENP-B by at least one method and all 39 samples (100%) were positive for either CENP-B or CENP-A in at least one of the tests. Regarding the clinical features, interstitial lung disease was less frequent in patients with AC-3 pattern compared to Non-AC-3 (10%versus54.2%; p=0.001). Other organ involvement parameters had similar frequencies between the groups.ConclusionsIn conclusion, the HEp-2-IFA method was 100% sensitive in detecting antibodies to CENP-A and CENP-B. Anti-CENP-B is the predominant autoantibody in samples yielding the AC-3 pattern, but exclusive anti-CENP-A reactivity was observed less frequently. Among lcSSc patients, anti-centromere reactivity was associated with less frequent lung involvement.