Residual cancer lymphocytes in patients with chronic lymphocytic leukemia after therapy show increased expression of surface antigen CD52 detected using quantitative fluorescence cytometry
| Authors | |
|---|---|
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | Clinical Lymphoma, Myeloma and Leukemia |
| MU Faculty or unit | |
| Citation | |
| Web | http://ac.els-cdn.com/S2152265014001487/1-s2.0-S2152265014001487-main.pdf?_tid=842eb21c-8153-11e4-96cb-00000aacb35f&acdnat=1418315822_d98aebf34d5184e1c7afe9df1e5ceb93 |
| Doi | http://dx.doi.org/10.1016/j.clml.2014.06.006 |
| Field | Oncology and hematology |
| Keywords | CD20, Remission, Residual Disease, Small lymphocytic lymphoma, Surface CD20 |
| Description | The quantitative determination of the expression of CD20 and CD52 antigens in chronic lymphocytic leukemia (CLL) is important for treatment with monoclonal antibodies (mAbs). Patients with CLL in complete or partial remission have a higher level of CD52 antigen expression compared with patients with CLL untreated, in progression, or diagnosed with small lymphocytic lymphoma (SLL). Our results support the possible signifi- cance of alemtuzumab consolidation. Background: Rituximab and alemtuzumab, mAbs used in recent years to treat CLL, are directed against antigens CD20 and CD52. CD20 is not highly expressed by CLL tumor cells, and rituximab does not have significant effectiveness in CLL unless combined with chemotherapy. Alemtuzumab targets CD52, which is much more highly expressed, and is currently the most effective agent used alone for CLL. Variability in expression of both antigens among these patients might be related to different individual therapeutic responses to mAb therapy. Patients and Methods: A total 95 patients diagnosed with CLL and/or SLL were divided into 4 groups: (1) untreated; (2) in complete or partial remission; (3) disease in progression; and (4) diagnosed with SLL. Flow cytometry of peripheral blood cells included gating of the CD5?CD19? tumor population, within which mean fluorescence intensity of fluorescein isothiocyanate (FITC) conjugated with anti-CD20 or anti-CD52 antibody was measured. The resulting expression of the 2 antigens was deduced from the calibration curve using Quantum FITC particles. Results: Expression of CD20 showed no significant differences among the 4 groups of patients. However, significantly greater expression of surface antigen CD52 was recorded in patient group 2 in complete or partial remission (P < .001). Conclusion: The residual population of CLL cells after therapy is characterized by increased surface detection of CD52. Although the exact cause of this phenomenon is unknown, our results provide a basis to consider the potential for CLL consolidation therapy using alemtuzumab. |
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