Specificity and reactivity of cytoplasmic and nucleolar antibody in SLE sera

Abstract
The serum of 2 of 31 patients with SLE was found to contain an antibody to a previously unrecognized RNA‐containing antigen found in human mononuclear cell cytoplasm and nucleolus. When tissue fixed, this antibody proved capable of fixing the patient's own rheumatoid factor and human complement components. No recognizable inhibition of complement fixation by rheumatoid factor could be demonstrated by the fluorescent antibody technic.