Significantly depressed percentage of CD27+(memory) B cells among peripheral blood B cells in patients with primary Sjogren's syndrome

CD27 has been found to be expressed on somatically mutated B cells and is t hus a positive marker for memory B cells in peripheral blood (PB). Since ab normal immunogloblin (Ig) production is characteristic of the autoimmune di seases primary Sjogren's syndrome (pSS) and rheumatoid arthritis (RA), we h ave analyzed in detail the CD27 expression on PB B cell from these patient groups. Staining of PB B cells with monoclonal antibodies (MoAb) specific f or CD19 and CD27 revealed a significantly depressed percentage of CD27+ PB B cells in patients with pSS (14.8 +/- 1.6%) compared to both healthy donor s (31.3 +/- 4.7%, P = 0.005) and patients with RA (40.8 +/- 4.1%, P = 0.000 1). In addition, the percentages of both the IgD+CD27+ and the IgD-CD27+ B- cell subpopulations were significantly lower in pSS patients compared to RA patients and healthy donors. However, the relative proportion of IgD- and IgD+ cells among the CD27+B cells were almost the same for the three groups . Our data suggest a disturbance in the differentiation of peripheral B cel ls and possibly a bias towards plasma cell differentiation, resulting in a depressed percentage of CD27+ memory PB B cells in pSS. These results are p otentially of pathological significance and of diagnostic value.