Bullous pemphigoid antigen concentration in normal human skin in relation to body area and age.

The amount of bullous pemphigoid antigen (BPA) in normal human skin on different areas of the body and in bodies of different ages was determined by making endpoint titer estimations using the indirect immunofluorescence technique. Two sera with bullous pemphigoid antibodies were tested with 36 specimens of normal human skin from six cadavers. The greatest expression of BPA was found in plantar sites, whereas the lowest endpoint titers were seen in flexural arm biopsy specimens. Age-dependent differences in BPA expression were detected as well. The oldest individuals tested produced the highest endpoint titers in contrast to the lowest endpoint titers in the youngest. This study suggests that the amount of BPA depends not only on the body region where the biopsy specimen is taken but also on the age of the donor. This is important to know in connection with indirect immunofluorescence assays for BP antibodies on human skin.