Inflammatory myopathy--early diagnosis and management by serum myosin light chains measurements.

The use of serum myosin light chain 1 (MLC1) in the diagnosis and treatment response of a patient with biopsy proven inflammatory myopathy is presented. A serum MLC1 level was elevated at presentation despite a normal creatine phosphokinase level. MLC1 levels more closely paralleled the clinical status than the aspartate aminotransferase and lactate dehydrogenase levels. The results suggest that MLC1 levels may facilitate the early diagnosis and management of patients with inflammatory myopathy. Moreover, the excellent response of our patient to low dose prednisone might suggest that the results of treatment could be improved by early detection and institution of therapy.