Antinuclear Factors in Systemic Lupus Erythematosus and Rheumatoid Arthritis

Abstract

Antinuclear factors (ANF) were investigated to determine their distribution among the three immunoglobulin classes in the sera of adults with systemic lupus erythematosus and rheumatoid arthritis and of children with rheumatoid arthritis. The presence of ANF in the sera was correlated with duration and severity of disease in the patients. The effect of corticosteroid therapy on the ANF titer and the course of disease was measured in 2 adults with SLE. Specificities of ANF for different nuclear antigens were investigated by ANF testing on nuclei of several organs and species. ANF of [gamma]2, [gamma]1A, and [gamma]1M immunoglobulin classes were found in some of the sera of children and adults with LE and RA. In RA, ANF were detected late in the course of the disease. During the course of disease in individual patients, [gamma]1M ANF generally appeared before 2 ANF. ANF in SLE were found in higher titers and with specificity for a greater variety of nuclei than was found with ANF in RA sera. It was concluded that the appearance of ANF in RA was a sequel to previously established disease and resembles the normal appearance of antibody after immunization with foreign antigens. The presence of high titer ANF of all 3 immunoglobulin classes at the time of initial diagnosis in SLE suggests that the immunization process in SLE begins long before the disease is clinically evident.