Rheumatoid arthritis (RA) is a serious chronic disease affecting a large number of patients and only symptomatic therapies are currently available. The majority of RA patients have elevated plasma levels of the rheumatoid factor (RF) autoantibodies directed to the Fc fragment of IgG. Prof. J. Natvig and coworkers have recently detected distinct Iymphoid structures in RA synovial tissues which have very close immunohistological characteristics to secondary follicles such as the presence of rnantle zone and germinal centers (GC) seen in secondary Iymphoid organs. The GC micro environments are intimately associated with clonal expansion and selection of B cells, sornatic hypermutation in B cell Ig V-region genes and induction of differentiation to memory B cells undergoing isotype switching and somatic mutations. The presence of such 'ectopic' Iymphoid tissue could be of crucial importance in the generation of auto-immune reactions. We intend to investigate whether the immune processes in GC from RA synovial tissues differ from those seen in normal, healthy Iymphoid tissue. We want study the germinal center formation and specially focus on the B and T Iymphocyte interactions and Follicular Dendritic Cells. FDC are a non lymphoid cells closely associated with B cells and encountered only in primary and secondary follicles. We want determine the relationship between these cells and B cells such as adhesion molecule expression and cytokine production. We want also study the features of GC T cells from RA synovial tissues (proportion. phenotype, CD57+, CD40L expression, etc). We want finally determine the degree of mutation and clonality in B-lymphocytes from GC identified in rheumatoid synovial tissues and studv how somatic mutations correlate with phenotypically separated B cells in rheumatoid synovial tissue as compared with normal secondary Iymphoid tissue.
Training content (objective, benefit and expected impact)
I did my Ph.D. in Immunology at Lund Universit -, Sweden, with Prof. Tomas Leanderson as supervisor The subject for the thesis was regulation of somatic mutation in immunoglobulin (Ig) genes. We have recently developed a system w ere somatic mutation can be supported in vitro in B cells from immunized mice. I have a long experience in amplifying and sequence V genes both directly from PCR and after cloning, I have also an extended knowledge of in vitro culturing of B cells However. I do not have the training in examine the synovial tissues in RA patients and the expcriencc in scparating different B cell developmental stages. As a scientist I would benefit tremendously from doing a post-doc in a laboratory w ith a different aspect on a similar scientific problem. It would strengthen my skills. knowledge and mv ability to do competitive science in the future. My expericnce gained in Sweden and Japan, particularly in the areas of expression systems and mutation processes in B cells would be of great benefit to the host laboratory. The results obtained will permit us to understand the defective mechanisms in the GC from RA svnovial tissues and identifv the factors which control RF and other autoantibodv production With this knowledge, we may bc able to address specific points of attack in the devclopment of a rational therapy and prophylaxis for this destructive disease.