Anti-idiotypic antibodies to four monoclonal IgM, one polyclonal IgM, and one polyclonal IgA rheumatoid factors were produced in rabbits and tested for cross reactivity with rheumatoid factors from nine patients with essential mixed cryoglobulinaemia, three patients with rheumatoid arthritis, four patients with systemic sicca syndrome, and one patient with systemic lupus erythematosus. Variable...
