2012 Volume 22 Issue 2 Pages 33-39
Introduction: Although follicular lymphoma (FL) is primarily a nodal lymphoma, the disease frequently involves the bone marrow (BM) and peripheral blood (PB). Methods: Of 67 FL patients in whom LN and BM specimens were analyzed by flow cytometry, 24 showed BM involvement. Of 12 patients in whom PB was simultaneously analyzed, we detected lymphoma cells in PB in 10, accounting for 3.7-87.3% of the lymphocyte fraction. We compared the cell-surface antigen expression of FL cells obtained from LN, BM, and PB of 8 patients. Results: The expression of CD10 in PB was down-regulated in 3 and lost in 5. Similarly, CD38 expression was down-regulated in 4 and lost in 3. In contrast, CD23 expression in PB was up-regulated in 3. The expression pattern of these three antigens in BM was similar to that of PB or intermediate between LN and PB. The monoclonal origin of lymphoma cells in LN and PB was confirmed by common chromosomal abnormalities and the identical BCL2/immunoglobulin heavy chain gene products. Conclusion: The CD10-/CD23+ phenotype can be shared by B-cell chronic lymphocytic leukemia and FL. Therefore, it is necessary to carefully differentiate these two disease entities. The down-regulation of CD10 and CD38 in BM/PB suggests that this phenotypic alteration may be advantageous when FL cells leave the follicular structure of LN.
