Clinical, serologic, and immunogenetic studies in patients with dermatomyositis

Dermatomyositis is a disease of unknown etiology characterized by progressive, symmetrical, proximal muscle weakness with accompanying compatible cutaneous findings. Thirty-nine patients with dermatomyositis from the Louisville, Kentucky area were enrolled in this study. Patients were grouped into those with or without a malignancy. Ten patients (26%) either had or have had a malignancy. Twenty-five Caucasian patients were HLA typed for the A, B, DR and DQ locus antigens, of whom 5 had an associated malignancy and 20 did not have a malignancy. We found that no single antigen had a significantly increased or decreased frequency as compared with our control population for the entire group, or for any clinical subset we examined. Serologic testing revealed 4 patients with anti-Mi-2 antibodies and 1 patient with anti-PM-SCL antibodies. No patient had a positive anti-Jo-1 antibody in this group. The results of serologic tests in this group did not correlate with any clinical subset or HLA antigen. Our findings were in agreement with the previous reports in which approximately 25% of patients with DM have an associated malignancy. Our findings also support the notion that untargeted malignancy searches are not warranted. Contrary to previous reports we did not observe an inverse relationship between cancer and pulmonary disease in the dermatomyositis patient. This study does not indicate that there are any HLA associations or clinical associations, other than age, that distinguish patients with dermatomyositis as running a greater risk of developing malignancy.