OBJECTIVE: Antibodies to F-actin have been proposed to increase specificity in the diagnosis of autoimmune hepatitis (AIH). We compared the diagnostic value of a new F-actin enzyme-linked immunosorbent assay (ELISA) with the current gold standard of detection of smooth muscle antibodies by indirect immunofluorescence (SMA-IFT). METHODS: Archived sera of 47 patients with SMA positive AIH were tested with the F-actin ELISA and SMA-IFT. Prospectively collected sera of 123 patients with various liver diseases, 35 of whom had AIH, were analyzed by both assays. Different cutoff limits were considered for the F-actin ELISA (increments between 20 and 60 ELISA units) and SMA-IFT (titers of 1:40, 1:80, and 1:160). RESULTS: The F-actin ELISA had a sensitivity of 100% to detect all of 47 SMA positive AIH sera and the value of the ELISA units correlated with that of SMA titers (p < 0.0001). In prospective analysis, F-actin ELISA showed a superior sensitivity (74% vs 34%) and a similar specificity (98% vs 99%) and positive predictive value (88% vs 92%), compared with SMA-IFT. Combining both assays improved neither sensitivity nor specificity. CONCLUSIONS: The new F-actin ELISA seems to be a useful diagnostic tool with similar specificity and superior sensitivity for the diagnosis of AIH, compared with standard SMA-IFT. Due to its simplicity and operator independency, the F-actin ELISA may become a preferred screening technique for detection of autoantibodies in patients with suspected AIH.
OBJECTIVE: Antibodies to F-actin have been proposed to increase specificity in the diagnosis of autoimmune hepatitis (AIH). We compared the diagnostic value of a new F-actin enzyme-linked immunosorbent assay (ELISA) with the current gold standard of detection of smooth muscle antibodies by indirect immunofluorescence (SMA-IFT). METHODS: Archived sera of 47 patients with SMA positive AIH were tested with the F-actin ELISA and SMA-IFT. Prospectively collected sera of 123 patients with various liver diseases, 35 of whom had AIH, were analyzed by both assays. Different cutoff limits were considered for the F-actin ELISA (increments between 20 and 60 ELISA units) and SMA-IFT (titers of 1:40, 1:80, and 1:160). RESULTS: The F-actin ELISA had a sensitivity of 100% to detect all of 47 SMA positive AIH sera and the value of the ELISA units correlated with that of SMA titers (p < 0.0001). In prospective analysis, F-actin ELISA showed a superior sensitivity (74% vs 34%) and a similar specificity (98% vs 99%) and positive predictive value (88% vs 92%), compared with SMA-IFT. Combining both assays improved neither sensitivity nor specificity. CONCLUSIONS: The new F-actin ELISA seems to be a useful diagnostic tool with similar specificity and superior sensitivity for the diagnosis of AIH, compared with standard SMA-IFT. Due to its simplicity and operator independency, the F-actin ELISA may become a preferred screening technique for detection of autoantibodies in patients with suspected AIH.
Authors: Jean P Molleston; William Mellman; Michael R Narkewicz; William F Balistreri; Regino P Gonzalez-Peralta; Maureen M Jonas; Steven J Lobritto; Parvathi Mohan; Karen F Murray; Dolores Njoku; Philip Rosenthal; Bruce A Barton; Monica V Talor; Irene Cheng; Kathleen B Schwarz; Barbara A Haber Journal: J Pediatr Gastroenterol Nutr Date: 2013-03 Impact factor: 2.839