A comparative study of immunological methods for determination of serum antinuclear antibodies

摘要

INTRODUCTION: Several immunological methods are used to determine the serum antinuclear antibodies (ANA). Indirect immunofl uorescence assay (IFA) with tissue slices or HEp-2 cells is the standard technique considered the gold standard for their screening. Serumfree McCoy-Plovdiv cell line may also be used as substrate for IFA. Another method for detection of total and specifi c ANA is the enzyme-linked immunosorbent assay (ELISA). Immunoblot is also applied in specifi c ANA confi rmation.The AIM of the current study was to determine and propose a justifi ed immunological approach for identifi cation of clinically signifi cant ANA by comparing the screening tests - ANA-IFA on serum-free McCoy-Plovdiv cell substrate with ELISA for total ANA, and confi rmative methods for specifi c ANA-ELISA with immunoblot.MATERIALS AND METHODS: Serum samples from 38 patients screened for total ANA by ELISA (Trinity Biotech, NY, USA) and IFA-ANA with МcCoy-Plovdiv cell line, were included in the study. Positive samples were confi rmed by immunoblot (Orgentec Diagnostika, Germany) and ELISA for specifi city of confi rmed ANA.RESULTS: No significant difference (Р > 0.05) and very good agreement were found between the two screening tests. Very good agreement for specifi c antibodies against SS-A, SS-B, dsDNA, moderate for anti-Sm and anti-Sm/RNP and fair for anti-histoneucleosomal antibodies was found between confi rmative methods. No agreement was found for anti-Scl-70 antibodies.CONCLUSION: IFA-ANA with serum-free МcCoy-Plovdiv cell line and screening ELISA may be recommended for determination of total ANA, and immunoblot and ELISA - for confi rmation and identifi cation of specifi c ANA.