Diagnostic value of the anti-Sa antibody compared with the anti-cyclic citrullinated peptide antibody in rheumatoid arthritis

Abstract

Aim: To evaluate the prevalence and diagnostic significance of the autoantibody against citrullinated vimentin (anti-Sa) compared with the widely used anti-cyclic citrullinated peptide autoantibody (anti-CCP) in patients with rheumatoid arthritis (RA).Method: One hundred and sixty-nine patients hospitalized at the Department of Rheumatology and Internal Medicine, Poznan University of Medical Sciences, Pozna n, Poland, were enrolled in a cross-sectional study and divided into two groups. The RA group comprised 41 patients diagnosed as having RA. The non-RA control group included 128 individuals with a variety of rheumatic disorders. Serum anti-Sa and anti-CCP measurements were performed by enzyme-linked immunosorbent assay. Results:The sensitivity and specificity of anti-Sa for the diagnosis of RA was 36.6% and 96.9%, respectively. For the anti-CCP test, the sensitivity was 65.9% and the specificity was 95.3%. Concomitant presence of anti-Sa and anti-CCP was determined in 36.6% of the patients with RA, whereas isolated positivity of anti-Sa was not observed. Anti-Sa positive RA patients had significantly higher anti-CCP levels compared to anti-Sa negative subjects (P < 0.05). Conclusion:With regard to the relatively low diagnostic sensitivity and the lack of cases identified by anti-Sa alone, we were unable to demonstrate any additional diagnostic value of the anti-Sa autoantibody in comparison to the anti-CCP autoantibody. To the authors' best knowledge, this is the first study among Polish patients verifying the clinical utility of anti-Sa in the diagnosis of RA.

Comparison of the diagnostic potential of three anti-citrullinated protein antibodies as adjuncts to rheumatoid factor and CCP in a cohort of South African rheumatoid arthritis patients

“…In the current study, elevated levels of anti-Sa showed an association with higher disease activity as previously reported [15,16], as well as with HLA-SE homozygosity and high-risk alleles. Interestingly, this finding of an association of anti-Sa autoantibodies with genetic predisposition and high risk have not, to our knowledge, been previously described, possibly justifying the inclusion of anti-Sa in the profile of serodiagnostic tests for our RA population.…”

Autoantibody and metalloproteinase activity in early arthritis

“…The presence of a-Sa antibodies may help to identify a subset of RA patient with aggressive early erosive disease [23]. Both markers have a high specificity and sensitivity, also corroborated in our study [22][23][24].…”

“…Iwaszkiewicz et al reached a different conclusion. They found no added diagnostic value from a-Sa testing, as RF (−) patients were also a-Sa (−) [22]. In our study, 25% of RF(−) RA and 22% of UA patients a-Sa (+).…”

“…In RA, they are present in 31-44% of patients, less commonly at the early stages of the disease. They are distinguished themselves by their high specificity, 92-98% [22].…”

The importance of differences; On environment and its interactions with genes and immunity in the causation of rheumatoid arthritis

“…Several other antibody reactivities have been shown to be present in smaller groups of RA patients, some being rather specific for RA, other being shared with other inflammatory diseases such as antibodies to SSA and SSB often in conjunction with RF [27]. Notably, antibodies to cartilage-derived collagen II (anti-CII) are present in one specific but rather small subsets of RA with a clinical acute onset phenotype [28][29][30].…”