Autoimmune Response Directed against Conserved Determinants of Nuclear Envelope Proteins in a Patient with Linear Scleroderma

We have studied the autoantibodies in the serum of a patient with linear scleroderma that specifically recognize the nuclear envelope of cultured cells. These antibodies bind to conserved determinants of nuclear lamins, the predominant mammalian nuclear envelope proteins. Of the three mammalian nuclear lamin proteins (P70, P68, and P60), only P70 and P60 bind the autoantibodies. In addition, two proteins of the Drosophila embryonic nuclear matrix, P70 and P68, bind these autoantibodies. We have used nuclear matrices to isolate the autoantibodies from the patient's serum that react to the nuclear lamins. At least three different IgG heavy chains were found to be involved in this autoimmune response to nuclear lamins, indicating that this response is not due to the expansion of a single B-cell clone.