The B lymphocyte in rheumatoid arthritis: Recirculation of B lymphocytes between different joints and blood

In order to search for further evidence for a pathogenetic role of recircul ating, antigen-driven B cell clones in rheumatoid arthritis (RA) rearranged VH genes were analysed for clonal relationship and somatic mutations from synovial tissue and peripheral blood of a patient with RA undergoing synove ctomy of several finger joints. DNA was prepared from the synovial tissue o f two finger joints and blood. PCR for the different VH families was perfor med with one specific oligonucleotide for each VH family and a mixture of J H-specific oligonucleotides. The PCR products were separated on a high reso lution acrylamide gel differentiating one base pair difference of length. T ransfer of the products onto a nylon membrane and hybridization with an oli gonucleotide specific for the FR3 region revealed a polyclonal representati on of rearranged VH1, VH3, VH4 and VH5 genes. The VH6 family, which is enco ded by a single germline gene, was represented by few distinct bands, with some bands of identical height for both joints and blood. DIVA from these b ands of interest was eluted, reamplified by PCR, cloned and sequenced. Sequ ence analysis of 27 independent bacterial colonies allowed distribution of the different VH genes to seven B cell clones (A-G). Members of clone A wer e found in both joints and blood, clones B and C in one joint and blood, cl one D in both joints, and clones E, F and G only in one joint. The VH regio ns were somatically mutated with characteristic patterns for the different clones. In conclusion, our findings confirm the systemic character of RA, b ecause they show that not only expansion and affinity maturation of B cells occur in synovial membranes but antigen-specific B cells recirculate betwe en different joints and blood.