When used as a diagnostic marker of bullous BP, the detection by ELISA of autoantibodies against either of the 2 BP antigens (BPAG1 or BPAG2) in the absence of clinical evidence of disease must be considered to be a false-positive finding, by definition, even though these autoantibodies can be shown to bind to purified antigen. However, such a finding may prove clinically relevant, as opposed to representing an epiphenomenon, if the presence of either autoantibody can be shown to predict who might later develop BP.
Fine J. Value of the Detection of Circulating Antibodies Against BP Antigens in Unaffected Subjects—Reply. Arch Dermatol. 2010;146(7):801-802. doi:10.1001/archdermatol.2010.138