Comparison of cell-ELISA, flow cytometry and Western blotting for the detection of antiendothelial cell antibodies

Objective There is still great uncertainty in the detection of antiendothelial cell antibodies (AECA) The aim of our study was to compare the results obtained using different methods. Methods Sera were obtained from 71 patients with a variety of vasculitides. Three assay methods were used: cell ELISA, flow cytometry (FACS) and Western blot (WB). Results In the ELISA 12/17 patients with systemic lupus erythematosus (SLE), 1/12 with Churg Strauss (CS) disease, 3/12 with micropolyarteritis (MPA) and 5/30 with Wegener's granulomatosis (WG) tested positive. Most of the sera that were positive on ELISA were not by FACS. Among the negative sera, 50% of WG, 40% of MPA, 20% of CS and 40% of SLE became positive on WB. There were some specific patterns of reactivity for a given disease, so that some bands could be assigned to a disease. Conclusion The discrepancies in the results may most probably be accounted for by differences between the antigenic preparations. Caution must thus be exercised when interpreting the results of any of these three tests.