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Systemic sclerosis is a generalized disorder of connective tissue clinically characterized by thickening and fibrosis of the skin and by distinctive forms of involvement of internal organs. One of the hallmarks of systemic sclerosis is the presence of serum autoantibodies against a variety of nuclear and cytoplasmic antigens. The primary purpose of this study was to identify the autoantibodies profile in the scleroderma sera and the secondary goal was to determine the correlation and discrepancy of autoantibody profile. Autoantibody profile was determined in 118 samples stored in the Advanced Diagnostic Laboratory at the University of Calgary. 78 sera were provided from Canadian and 40 sera were provided from Ukraine. We used the following techniques to identify autoantibodies profile in scleroderma patients: 1. Antinuclear antibody (ANA) by indirect immunofluorescence on human epithelial cell substrate 2. Detection and identification of specific autoantibodies by Innolia strip assay 3. Detection and identification of specific autoantibodies against extractable nuclear antigens. 111 out of 118 patients showed positive ANA results by indirect immunofluorescence and 7 patients had negative ANA results. Anti-ENA analyses by Inolia were positive in 84 patients, while by western blotting 81 patients showed positive results. In this study, we compared the results of anti-ENA antibody by Innolia with SLR technique. A significant correlation was found between anti-SC1-70 antibodies (P=0.000) and anti- RNP antibodies (P=0.001) and JO-1 antibodies (P=0.014). Thus, we may propose that SLR and Innolia techniques could be used for the detection of autoantibody in systemic sclerosis.

Background: Following the introduction of addressable laser bead immunoassays (ALBIA) into our clinical laboratory, it was noted that certain sera would exhibit reactivity to numerous antigens in the array. To further understand the nature of this reactivity, we analyzed the reactivity of sequential sera that were identified over a 1 year period., Methods: Sera that demonstrated reactivity to 6 or more of the 8 antigens in an ALBIA kit (QuantaPlex 8: chromatin, Sm, RNP, Scl-70, ribosomal P protein, SS-A/Ro, SS-B/La, Jo-1) were tested for autoantibodies by indirect immunofluorescence (IIF) on HEp-2 cell substrates, for IgG, IgM and IgA rheumatoid factor, chromatin and ribosomal P protein by ELISA and by LINE immunoassay (LIA) and immunoblotting (IB)., Results: In one calendar year, 40/4096 (0.8%) sera analyzed in a routine clinical laboratory setting demonstrated reactivity to 6 or more antigens in the QuantaPlex 8 kits. There was no common IIF pattern that could be attributed to the polyreactive sera. There was no apparent correlation of polyreactivity with IIF titers, indeed, 4/40 (10%) sera had a negative ANA at the screening dilution of 1/160. When subjected to IB, LIA and ELISA, polyreactivity to three or more antigens was confirmed for 12/40 (30%) of sera while 8/40 (20%) had reactivity to 1-2 antigens and 20 (50%) did not react with any antigens in these assays. Overall agreement of positive or negative tests between the ALBIA and IB, LIA and ELISA was 75% for chromatin, 50% for SS-A, 27.5% for Sm, 25% for Rib-P, 22.5% for RNP, 20% for Scl-70, 15% for Jo-1 and 7.5% for SS-B. 17/40 (42.5%) had a positive IgM, IgG or IgA rheumatoid factor, and 12/40 (30%) had all three isotype rheumatoid factors., Conclusions: On average, the agreement between ALBIA and other assays in this study of polyreactive sera was 30%. Approximately, one-half of sera that demonstrate reactivity to multiple autoantigens in a commercial ALBIA were confirmed to have reactivity to at least one autoantigen in another diagnostic assay and 30% could be regarded as polyreactive. Other sera, some of which had rheumatoid factor, appeared to have high background binding without demonstrating specific binding to any of the cognate antigens.