The mosaic of B-cell subsets (with special emphasis on primary Sjogren's syndrome)

Major breakthroughs have occurred with classification of B-cells into populations and subpopulations. With respect to their expression of CD5, they comprise the B I and 132 populations, with the former further divided into B1a and B1b subpopulations. The oncologic process starts from transitional type 1 (T1) and T2 immature B-cells, through marginal zone or germinal center B-cells, ending up with memory B-cells and plasma cells (PCs). They may also be categorized based on their functional commitment with polarized B effector (Be)1 and Be2, with B-activating factor of the tumor-necrosis factor-producing B-cells, and with short-lived and long-lived PCs. Such a seemingly homogeneous family of cells has thus turned out to be a genuine mosaic of B-lymphocyte subsets. (c) 2006 Elsevier B.V. All rights reserved.