Hairy Cell Leukemia and Variant: Immunophenotypic Comparison and Variations.
Haipeng Shao, Marlene Gronborg, Constance M Yuan, Robert J Kreitman, Maryalice Stetler-Stevenson. National Cancer Institute, National Institutes of Health, Bethesda, MD; H Lee Moffitt Cancer Center and Research Institute, Tampa, FL
Background: Hairy Cell Leukemia (HCL) and Hairy Cell Leukemia Variant (HCLv) are rare chronic lymphoproliferative disorders with different clinical manifestations. In comparison with HCL, HCLv has a more rapid disease progression, shorter median survival, and is unresponsive to purine analog therapy. Accurate diagnosis of HCL and HCLv is important for optimal treatment strategy. HCL and HCLv both express CD19, CD20 (bright), CD22 (bright), CD11c (bright), and are usually negative for CD5, CD10, CD23 and CD38. They differ in the expression of CD25, CD123 and sometimes CD103 but can still be difficult to distinguish at times.
Design: Immunophenotypic data of 1380 HCL cases from 173 patients and 116 cases of HCLv from 24 patients and WBC data for 102 HCL and 18 HCLv cases received at NCI between 1999 and 2009 was retrospectively examined. Corresponding bone marrow and splenectomy specimens were reviewed as well.
Results: HCL and HCLv differed dramatically in WBC, with WBC means for HCL being 8.0x109/L (range: 0.6-142.0x109/L) and HCLv being 69.8x109/L (range: 2.2-839.2x109/L), respectively (P=0.0019). HCL cases were positive for CD11c (99%), CD25 (97%), CD103 (96%), CD123 (100%), CD5 (2%), CD10 (12%), CD23 (21%), CD38(14%), CD2 (2%), CD4 (0.5%), and CD13 (0.5%). HCLv cases were positive for CD11c (100%), CD103 (71%), CD5 (4%), CD10 (4%), CD23 (8%), CD2 (13%), CD123 (45%), and CD13 (4%), and negative for CD25. There is no preferential usage of kappa or lambda light chains in either HCL or HCLv. 1% of HCL and 4% of HCLv patients showed variable antigen expression between different specimens. Three HCL patients had simultaneous presence of HCL with other small B-cell lymphoproliferative disorder, including one with CLL.
Conclusions: The four markers, CD11c, CD25, CD103, and CD123 are essential for correct diagnosis of HCL and HCLv. Immunophenotypic variations in the expression of CD5, CD10, CD23, CD38, CD2 and CD13 happen in both HCL and HCLv. HCL can occur simultaneously with other small B-cell lymphoproliferative disorders.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 169, Wednesday Morning