Monoclonal gammopathies in aging mu, kappa-transgenic mice: involvement of the B-1 cell lineage

B cell chronic lymphocytic leukemia: lessons learned from studies of the B cell antigen receptor

B cell chronic lymphocytic leukemia (B-CLL) is an accumulative disease of slowly proliferating CD5(+) B lymphocytes that develops in the aging population. Whereas some patients with B-CLL have an indolent course and die after many years from unrelated causes, others progress very rapidly and succumb within a few years from this currently incurable leukemia. Over the past decade studies of the structure and function of the B cell antigen receptor (BCR) used by these leukemic cells have helped redefine the nature of this disease. In this review we summarize and reinterpret several aspects of these BCR-related studies and how they might relate to the disease. In particular, we address the ability of antigens to select out and drive B cell clones from the normal state to overt leukemic cells by binding to BCRs that are relatively unique and characteristic of B-CLL cells. The differential capacity of some B-CLL cases to continue to transduce signals through the BCR during the leukemic phase and the consequences for the in vivo biology of the leukemic clone is also considered. Finally, we discuss current and emerging views of the cellular origin of B-CLL cells and the differentiation pathways down which we believe these cells progress.

Biological ageing research in the Netherlands

After an introduction on the development of biological ageing research in the Netherlands during the past decades, 606 papers on aging published by Dutch institutes in the period 1991-2000, collected from PubMed, were analysed for their relevance to research into biological ageing. For the period 1996-2000, the total number of research papers on biological ageing amounted to 142, which accounts for 23% of all publications on ageing in that period. The number of publications per year did not change. On the basis of these papers and additional information provided by research groups a comprehensive overview of biological ageing research in the Netherlands is presented, together with an extensive literature list. Ageing of the central nervous system (CNS), of the endocrinological system and of the cardiovascular system are the topics most studied. It is concluded that general biological ageing research has not increased in the Netherlands over the last ten years, and that the infrastructure for basic biological ageing research in the Netherlands is weak.

Changes in the B-cell repertoire with age

Changes in the B-cell repertoire during aging include a shift in antibody specificities from foreign to autologous antigens associated with a decline in the activity of conventional B2 compared to B1 lymphocytes. The age-associated increase in B1 lymphocyte number and activity contribute to the increased serum concentration of autoantibodies and the B-cell clonal expansions that develop with age. Aging is also associated with a decreased diversity of the antibody response reflected in the preferential loss of IgG and high affinity antibodies following immunization with a foreign antigen. Many of these changes can be traced to an impaired capacity of T cells to support isotype switching and somatic mutation in the periphery and the generation of a diverse B-cell repertoire from bone marrow B-cell precursors.