In vitro production of monoclonal human rheumatoid factors.

Lymphocytes from rheumatoid arthritis patients have been fused with drug-marked human myeloma cell lines and hybrids selected which secrete rheumatoid factors. Limiting dilution and soft agarose plates have been used to clone these hybrids, but so far stable clones have not been obtained. Epstein-Barr virus has been used to transform lymphocytes, and clones which secrete rheumatoid factors have been obtained.