Antinuclear antibody with distinct specificity for polymyositis

Area of Science:

• Immunology
• Rheumatology
• Autoimmunity

Background:

• Antinuclear antibodies are crucial in diagnosing rheumatic diseases.
• A novel precipitin reaction, PM-1, was observed between calf thymus nuclear extract and polymyositis sera.

Purpose of the Study:

• To characterize the immunologic nature of the PM-1 reaction.
• To determine the specificity of PM-1 for polymyositis.

Main Methods:

• Immunodiffusion assays using calf thymus nuclear extract.
• Enzyme and heat treatments to differentiate PM-1 from known antigens.
• Serum fractionation via ammonium sulfate precipitation and Sephadex G-200 chromatography.
• Immunoelectrophoresis to identify the immunoglobulin class.

Main Results:

• The PM-1 precipitin line was detected in 17 of 28 polymyositis patients.
• Sera from 460 patients with other diseases did not produce the PM-1 reaction.
• PM-1 was found to be distinct from native DNA, ribonucleoprotein, and Sm antigens.
• The reactive factor in PM-1-positive sera was identified as IgG.

Conclusions:

• The PM-1 system demonstrates high specificity for polymyositis.
• PM-1 may serve as a valuable diagnostic marker antibody for polymyositis.