IMMUNE-MEDIATED SUBEPITHELIAL BLISTERING DISEASES OF THE MUCOUS-MEMBRANES - IMPROVING THE DETECTION OF CIRCULATING AUTOANTIBODIES BY THE USE OF CONCENTRATED SERUM SAMPLES

Background and Design: Comparison of detection of circulating autoanti bodies before and after concentration of serum samples from patients w ith suspected immune-mediated subepithelial blistering diseases of the mucous membranes. We determine whether the use of concentrated serum samples from patients with suspected immune-mediated subepithelial bli ster ring diseases oi the mucous membranes improves diagnostic sensiti vity for circulating antibodies. We studied 13 patients from a univers ity-based referral practice who had no skin lesions and a scarring sub epithelial blistering disease of the mucous membranes. Three of these patients had detectable circulating autoantibodies and 10 had negative indirect immunofluorescence study results using standard techniques. The main outcome measures after concentration of serum samples were de tection of circulating autoantibodies on salt-split skin by indirect i mmunofluorescence, immunoblotting, and immunoprecipitation. Results: O f the 10 patients in whom circulating autoantibodies had not been dete ctable with standard techniques, circulating IgG antibodies were detec ted in 5 (50%) and circulating IgA antibodies in 3 (30%). Of the 3 pat ients in whom circulating autoantibodies had been detectable with stan dard techniques, 1 (33%) had circulating IgA antibodies that immunoblo tted the 97-kd linear IgA bullous disease antigen only when concentrat ed serum samples were used. Conclusions: The use of concentrated serum samples can improve our ability to detect the presence and antigenic specificity of circulating autoantibodies in patients with suspected b ut unclassifiable immune-mediated subepithelial blistering diseases of the mucous membranes.