PERSISTENCE OF A RHEUMATOID-FACTOR (RF)-PRODUCING B-CELL CLONE WITH ASOMATICALLY MUTATED IG-KAPPA CHAIN IN A PATIENT WITH RHEUMATOID-ARTHRITIS

The V kappa IV gene encoding the light chain of an IgA RF has been sho wn to have undergone 31 somatic mutations compared with the single exi sting V kappa IV germ-line gene. We now show the persistence of the re arranged and mutated DNA coding for this RF over a period of 5 years i n the peripheral blood lymphocytes (PBL) of the patient with rheumatoi d arthritis (RA). The sequence of the RF has been conserved to identit y over this period. These results raise the possibility that the parti cular antigenic stimulus leading to RF production in this RA patient i s active over a long period of time.