Browsing by Author "Langerak, AW"
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- Molecular and cytogenetic characterization of expanded B-cell clones from multiclonal versus monoclonal B-cell chronic lymphoproliferative disorders.Publication . Henriques, A; Rodriguez-Caballero, A; Criado, I; Langerak, AW; Nieto, WG; Lecrevisse, Q; Gonzáles, M; Cortesão, E; Paiva, A; Almeida, J; Orfão, AChronic antigen-stimulation has been recurrently involved in the earlier stages of monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. Among these individuals, expansion of ≥2 B-cell clones has been frequently reported; potentially, such coexisting clones have a greater probability of interaction with common immunological determinants. Here, we comparatively analyzed the B-cell receptor repertoire and the molecular profile, as well as the phenotypic, cytogenetic and hematological features of 228 chronic lymphocytic leukemia-like and non-chronic lymphocytic leukemia-like clones between multiclonal (n=85 clones from 41 cases) versus monoclonal (n=143 clones) monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The B-cell receptor of B-cell clones from multiclonal cases showed a slightly higher degree of HCDR3 homology than B-cell clones from monoclonal cases, in association with unique hematological (e.g. lower B-lymphocyte counts) and cytogenetic (e.g. lower frequency of cytogenetically altered clones) features usually related to earlier stages of the disease. Moreover, a subgroup of coexisting B-cell clones from individual multiclonal cases which were found to be phylogenetically related, showed unique molecular and cytogenetic features: they more frequently shared IGHV3 gene usage, shorter HCDR3 sequences with a greater proportion of IGHV mutations and del(13q14.3), than other unrelated B-cell clones. These results would support the antigen-driven nature of such multiclonal B-cell expansions, with potential involvement of multiple antigens/epitopes.
- Phenotypic profile of expanded NK cells in chronic lymphoproliferative disorders: a surrogate marker for NK-cell clonalityPublication . Bárcena, P; Jara-Acevedo, M; Tabernero, MD; López, A; Sánchez, ML; García-Montero, AC; Muñoz-García, N; Vidriales, MB; Paiva, A; Lecrevisse, Q; Lima, M; Langerak, AW; Böttcher, S; van Dongen, JM; Orfão, A; Almeida, JCurrently, the lack of a universal and specific marker of clonality hampers the diagnosis and classification of chronic expansions of natural killer (NK) cells. Here we investigated the utility of flow cytometric detection of aberrant/altered NK-cell phenotypes as a surrogate marker for clonality, in the diagnostic work-up of chronic lymphoproliferative disorders of NK cells (CLPD-NK). For this purpose, a large panel of markers was evaluated by multiparametric flow cytometry on peripheral blood (PB) CD56(low) NK cells from 60 patients, including 23 subjects with predefined clonal (n = 9) and polyclonal (n = 14) CD56(low) NK-cell expansions, and 37 with CLPD-NK of undetermined clonality; also, PB samples from 10 healthy adults were included. Clonality was established using the human androgen receptor (HUMARA) assay. Clonal NK cells were found to show decreased expression of CD7, CD11b and CD38, and higher CD2, CD94 and HLADR levels vs. normal NK cells, together with a restricted repertoire of expression of the CD158a, CD158b and CD161 killer-associated receptors. In turn, NK cells from both clonal and polyclonal CLPD-NK showed similar/overlapping phenotypic profiles, except for high and more homogeneous expression of CD94 and HLADR, which was restricted to clonal CLPD-NK. We conclude that the CD94(hi)/HLADR+ phenotypic profile proved to be a useful surrogate marker for NK-cell clonality.