Specificity of HMGCR-coated beads. (A) HMGCR, signal recognition particle (SRP) and intrinsic factor-specific beads were coupled to the corresponding recombinant protein and analyzed by ALBIA using a human anti-HMGCR, anti-SRP or anti-intrinsic factor positive serum. (B) Dose-dependent inhibition of human anti-HMGCR antibodies binding to HMGCR-coated beads by free human recombinant HMGCR protein. Percent inhibition is given relative to the mean fluorescence intensity (MFI) value in the absence of free HMGCR. (C) Specific inhibition by homologous HMGCR but not heterologous proteins. Percent inhibition of three different human anti-HMGCR positive sera (referred to as #1, #2 and #3) by 100 μg/mL of free HMGCR, SRP or intrinsic factor proteins. (D) Immunoprecipitation of HMGCR protein by ALBIA-HMGCR positive or negative human sera. A rabbit anti-HMGCR polyclonal antibody was used as positive control. ALBIA, addressable laser bead immunoassay; HMGCR, 3-hydroxy-3-methylglutaryl coenzyme A reductase.