Indirect immunofluorescence on different cell line in detection of cell membrane DNA antibody in juvenile systemic lupus erythematosus

Objective To detect anti-cell membrane DNA(cmDNA)antibody with human B lymphocyte Raji cells and human promyelocytic leukemia HL60 cells as substrates and to compare the diagnostic value of anti-cmDNA antibody with that of anti-nucleosome antibody(AnuA), anti-Sm antibody and anti-double-stranded DNA(dsDNA)antibody in juvenile systemic lupus erythematosus(JSLE)patients. Methods We recruited 92 JSLE patients and 71 patients with other rheumatic diseases.Anti-cmDNA antibody andantinuclear antibody(ANA)was detected in patient serum by indirect immunofluorescence assays(IIF). Anti-dsDNA antibody were detected by combining enzyme-linked immuno sorbent assay(ELISA)and IIF.Anti-Sm antibody were detected by double immunodiffusion assay and immunoblotting, while anti-nucleosome antibody(AnuA)were detected by ELISA.We collected concurrent clinical data. Results Anti-cmDNA antibody demonstrated stronger intensity of fluorescent patterns in using Raji cells as substrate than HL60 cells.JSLE patients had a significantly higher positive percentage of anti-cmDNA than patients with other rheumatoid diseases.The sensitivity of anti-cmDNA on cell line Raji was higher than that of anti-dsDNA and anti-Sm(P 0.05)and was lower than anti-Sm and AnuA(P 0.05)and the specificity was lower than AnuA(P<0.01). The sensitivities of anti-dsDNA, anti-Sm and AnuA by combining with anti-cmDNA were much higher than that of the above antibody detected respectively(P<0.05). Anti-cmDNA had no correlation with SLE disease activity index(P=0.907). Conclusion The high sensitivity and specificity of anti-cmDNA antibody make it a valuable diagnostic tool for JSLE.Combined detection of anti-cmDNA and other autoantibody might further improve the sensitivity in JSLE.Anti-cmDNA detected with IIF on cell line Raji was better than cell line HL60. Key words: Systemic lupus erythematosus; Child; Diagnosis; Anti-cmDNA antibody