13 research outputs found
Inhibitory serum factor of lymphoproliferative response to allogeneic cells in pregnancy
Relationship between MLR blocking antibodies and the outcome of the third pregnancy in patients with two consecutive spontaneous abortions
Increased susceptibility of cord blood B lymphocytes to undergo spontaneous apoptosis
In this study, we compared the rate of spontaneous apoptosis of B cells from umbilical cord blood with adult B cells and assessed the role of Bcl-2, CD5, interleukin (IL)-4 and B cell-activating factor in B cell spontaneous apoptosis. We found that spontaneous apoptosis of cultured B cells, as assessed by utilizing annexin-V binding, was significantly higher in cord blood than in healthy adult individuals (77·5; 95 CI, 73·5–81·5 versus 59·2; 95 CI, 54–64, respectively, P < 0·0001) and further confirmed by 4′ 6-diamidino-2-phenylindole, dihydrochloride (DAPI) staining. Whereas the expression of B cell-activating factor from the tumour necrosis factor family (BAFF) receptor mRNA was similar in B cells from adults and cord blood, we detected lower levels of circulating BAFF in the serum of cord blood (0·68 ± 0·13 ng versus 1·83 ± 0·54 ng, P = 0·01). The latter may explain, in part, our observation of lower levels of mean fluorescence intensity of Bcl-2 in cord B cells compared with adults (1·6 ± 0·9 versus 2·85 ± 1·3, P = 0·033). CD19(+) CD5(+) B cells from cord blood underwent a lower rate of apoptosis in comparison to CD19(+) CD5(−) B cells (25·1 ± 9·3% versus 58·5 ± 12·5%, P < 0·0001). This pattern of sensitivity was comparable in adult blood (15 ± 5·5% versus 22·7 ± 9·3%, P = 0·01). Nevertheless, the rate of apoptosis was higher in CD19(+) CD5(+) from cord blood compared to CD19(+) CD5(+) from adults (25·1 ± 9·3% versus 15 ± 5·5%, P = 0·0013). The addition of rIL-4 (10 u/ml) to cultured cells decreased B cell apoptosis in a similar fashion in both cord and adults blood. This rescue was strengthened when BAFF (100 µg/ml) was further added. Thus, alterations in Bcl-2 or serum BAFF level may explain the increased rate of cord blood B cell apoptosis