Applicability of 19–DEJ-l monoclonal antibody for the prenatal diagnosis or exclusion of junctional epidermolysis bullosa

Recently a monoclonal antibody (19–DEJ-l) was produced with binding specificity for the mid-lamina lucida of the skin dermoepidermal junction, in very close association with overlying hemidesmosomes. Since skin cleavage occurs within the lamina lucida in the inherited blistering disorder, junctional epidermolysis bullosa (EB), and is associated with aberrations in the morphology and/or number of hemidesmosomes in such tissue, we have sought to determine whether this monoclonal antibody could be used for prenatal diagnosis. Fetoscopy-directed skin biopsies were obtained from two fetuses at risk for junctional EB and post-mortem samples from two other fetuses with the Herlitz type of junctional EB, the latter after prenatal diagnosis by electron microscopy and termination of each pregnancy. Specimens were examined in part by light and electron microscopy for evidence of skin cleavage or other alterations in morphology, and in part by indirect immunofluorescence for altered basement membrane antigenicity. Three of four fetuses were shown to have intra-lamina lucida blister formation indicative of, and hemidesmosome hypoplasia proving, junctional EB. Each was also shown to lack expression of GB3 and 19–DEJ-l antigens, consistent with findings noted postnatally in junctional EB; diagnosis was confirmed in each at the time of therapeutic abortion. A fourth fetus had no abnormalities detected; lack of disease involvement was confirmed at the time of delivery, and subsequently over 8 months of careful serial evaluation. We conclude that 19–DEJ-l monoclonal antibody is an accurate and sensitive irnmunohistochemical probe for junctional EB, and may be employed in the prenatal diagnostic evaluation of fetuses at risk for this disorder.