The
dystrophin test was performed on skeletal muscle specimens from 81 cases with various
neuromuscular diseases by using two new
monoclonal antibodies. The results were compared with those obtained by using four polyclonal
antibodies. These monoclonal and polyclonal
antibodies were raised against various portions of the
dystrophin molecule. On immunohistochemical analysis, the two new
monoclonal antibodies showed the same staining pattern as the four polyclonal
antibodies. Non-specific immunostaining of the cytoplasm, often seen with polyclonal
antibodies, was not observed with
monoclonal antibodies. With the application of
monoclonal antibodies, the connective tissue sometimes showed non-specific immunostaining which originated from the second fluorescent antibody. On immunoblot analysis, one of the two
monoclonal antibodies, antibody 4-4 C 5, showed weak immunoreactivity, and the 400 kDa
dystrophin band was not detected. Three cases out of 15 with
Duchenne muscular dystrophy (DMD), and one case out of 3 with limb-girdle type
muscular dystrophy which had previously been diagnosed on the basis of clinical data, were found to have non-
dystrophin-related
muscular dystrophy, and
Becker muscular dystrophy (BMD), respectively. Three and two of five cases were diagnosed as DMD and BMD, respectively, though clinical diagnosis had not been possible because they were too young. Clinical diagnosis of congenital
muscular dystrophy was confirmed in 9 patients by the
dystrophin test. Only one of three certain DMD carriers had a so-called mosaic staining pattern. We conclude that all six
antibodies are useful tools for the diagnosis of
neuromuscular diseases, because of their high specificity for
dystrophin.