Robak, T.; Krawczyńska, A.; Cebula-Obrzut, B.; Urbaniak, M.; Iskierka-Jażdżewska, E.; Robak, P. Atypical Chronic Lymphocytic Leukemia—The Current Status. Cancers2023, 15, 4427.
Robak, T.; Krawczyńska, A.; Cebula-Obrzut, B.; Urbaniak, M.; Iskierka-Jażdżewska, E.; Robak, P. Atypical Chronic Lymphocytic Leukemia—The Current Status. Cancers 2023, 15, 4427.
Robak, T.; Krawczyńska, A.; Cebula-Obrzut, B.; Urbaniak, M.; Iskierka-Jażdżewska, E.; Robak, P. Atypical Chronic Lymphocytic Leukemia—The Current Status. Cancers2023, 15, 4427.
Robak, T.; Krawczyńska, A.; Cebula-Obrzut, B.; Urbaniak, M.; Iskierka-Jażdżewska, E.; Robak, P. Atypical Chronic Lymphocytic Leukemia—The Current Status. Cancers 2023, 15, 4427.
Abstract
A diagnosis of typical chronic lymphocytic leukemia (CLL) requires the presence of ≥5000 clonal B-lymphocytes/μL with the coexistence of CD19, CD20, CD5, and CD23 and the restriction of light chain immunoglobulin, and the lack of expression of antigens CD22 and CD79b. Atypical CLL (aCLL) can be distinguished from typical CLL morphologically and immunophenotypically. Atypical CLL cells are defined as prolymphocytes; morphologically, these present as deeply-clefted lymphocytes which are larger than those in typical CLL, with condensed chromatin and without prominent nucleoli. However, current aCLL diagnostics rely more on immunophenotypic characteristics rather than atypical morphology. Immunophenotypically, atypical CLL differs from classic CLL in the lack of expression of one or fewer surface antigens, most commonly CD5 and CD23, and the patient does not meet the criteria for a diagnosis of any other B-cell lymphoid malignancy. Morphologically atypical CLL has more aggressive clinical behavior and worse prognosis than classic CLL. Patients with aCLL are more likely to display markers associated with poor prognosis, including trisomy 12, unmutated IGVH, and CD38 expression compared with classic CLL. However, no standard or commonly-accepted criteria exist for differentiating aCLL from classic CLL and the clinical significance of aCLL is still under debate. This review summarizes the current state of knowledge on the morphological, immunophenotypic and genetic abnormalities of aCLL.
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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