Antinuclear antibodies and nuclear antigens in NZB myeloma ascitic fluids

Approximately 5-10% of ascitic fluids from 411 NZB myeloma tumors were found to possess either antinuclear (ANA) or Coombs antibodies. Some fluids showed anti-SM specificity, which is thought to be unique to systemic lupus erythematosus (SLE). In addition, the ascitic fluids were found to contain large amounts of DNA and Sm autoantigens. Further passage of ANA-positive myelomas indicated that the autoantibodies were not products of the myeloma cells themselves. The sporadic appearance of unsuspected autoantibodies in ascitic fluids may cause confusion when working with myeloma or with hybridoma reagents. Furthermore, the development of SLE-specific anti-Sm antibodies in this context suggests parallels between myeloma development and autoimmunity.