Rosette formation by circulating lymphocytes from rheumatoid and nonrheumatoid subjects.

In the majority of patients with rheumatoid arthritis the immune response is most readily detected as a production of rheumatoid factors, IgM antibodies, which agglutinate to high titre erythrocytes coated with IgG antibodies from man, rabbit, or sheep, etc. Generally, only low titres of rheumatoid factors are found in nonrheumatoid individuals. Bach, Delrieu, and Delbarre (1970a, b) described circulating human lymphocytes which bear surface receptors with antiglobulin activity. Upon mixing and centrifuging with human erythrocytes coated with rabbit antibody, each lymphocyte was surrounded by adherent erythrocytes to form a rosette; usually fewer than six rosetteforming lymphocytes per thousand were found in control subjects, whereas over 70 per cent of patients with rheumatoid arthritis gave greater numbers. Patients with gout gave increased rosette counts. These authors suggested that the lymphocyte response of the rheumatoid individual precedes the appearance of humoral rheumatoid factors and that the process may correspond to that found in animals after immunization (Brown and Epstein, 1969). In order to examine the properties and occurrence of rosette-forming lymphocytes, we have tested lymphocyte preparations from normal subjects of various ages, patients suffering from rheumatoid arthritis, and patients with orthopaedic conditions not related to rheumatoid arthritis.