The expression of
type VII collagen and
19-DEJ-1 antigen was examined in 73 and 71 patients, respectively, with recessive
dystrophic epidermolysis bullosa (RDEB), comprising gravis, mitis, inversa, and indeterminant subsets, to better determine the specificity and sensitivity of two
monoclonal antibodies directed against these dermoepidermal junction-specific
epitopes.
Type VII collagen (LH 7:2
epitope) was usually absent (in 90%) in patients with the gravis variant of RDEB, whereas its expression was most often diminished (in 67%) in those with the mitis form of the disease. Only 2% and 5% of patients with gravis and mitis variants, respectively, had apparent normal amounts of
type VII collagen within their skin. In contrast, six (86%) of seven patients with the inversa variant had normal expression of the
antigen. Only 25% of all patients with RDEB lacked the
19-DEJ-1 antigen; of these, however, most had the gravis variant, although absence or diminution was also infrequently observed in those with the mitis and inversa forms. Intermediate findings were noted in patients classified as having indeterminant forms of RDEB. Some variability in
antigen expression was also noted among affected siblings. We conclude that assessment of expression of the LH 7:2
epitope of
type VII collagen may be diagnostically useful, although considerable overlap does exist between individual patients with gravis and mitis forms. 19-DEJ-1 expression is a far less sensitive probe in RDEB, although such data may prove useful in the assessment of newborns lacking the characteristic features of gravis disease. In addition, based on our experience with inversa RDEB, it would appear that altered expression of
type VII collagen cannot be attributed to
blister formation in this latter rare subset, since this
antigen is usually strongly detected along the dermoepidermal junction, even in perilesional skin sites.