A comparative study of immunofluorescence pattern and line immune assay profile in the detection of the antinuclear antibodies

Abstract

Background and Aims: To compare the efficacy of the Immunofluorescence and Line Immune Assay profile in the detection of ANA antibody. To ascertain an association between ANA patterns and the specific antibodies. To correlate the obtained ANA patterns with the Immunoassay. Settings and Design: This cross sectional study was done at a tertiary care center at Hyderabad Telangana. The samples were tested for ANA by Indirect Immunofluorescence (IIF) method and by Line immunoassay (LIA) methods. Materials and Methods: Serum samples of patients with a clinical suspicion of autoimmune disease were tested for ANA by indirect immunofluorescence (IIF) method and Line immunoassay (LIA) during January 2018-December 2018. Serum samples for indirect immunofluorescence were processed in 1:100 dilution using HEp–2010/liver/stomach/kidney biochip (EUROIMMUN AG). The serum samples were further processed for the line immunoassay in 1:100 dilution on nylon strips coated with purified and recombinant antigens as discrete lines with plastic backing coated with the antigens nRNP/Sm, Sm, SSA, Ro-52, SSB, PM-Scl, Scl-70, PCNA, Jo-1, CENP-B, dsDNA, nucleosomes, ribosomal protein-P, histones, anti-mitochondrial antibodies (AMA-M2) along with the control band. The analysis was done by the comparison of the intensity of reaction with the positive control line by image analysis. Results: Out of 236 samples tested, 77 were tested positive for Immunofluorescence and Line immuno assay, 115 were tested negative for Immunofluorescence and Immunoblot assay, only 1 was tested positive for Immunofluorescence and negative for Line immunoassay and 43 were tested positive for Line immunoassay and negative for Immunofluorescence. Conclusion: Detection of ANA by IIF method is a cost effective method. It may be used for the screening purposes for patients with or without clinical criterion for the autoimmune disease in daily clinical practice. The fluorescent pattern can also predict presence of certain specific antibodies in the sera. This may regulate one from requesting for line immunoassay, which is expensive. The Line Immuno assay may be reserved for those patients who need them for prognostic significance.