Novos marcadores imunofenotípicos e sua utilidade no diagnóstico e classificação de neoplasias de células B maduras CD5-positivo, linfomas vilosos e neoplasias plasmocitárias por citometria de fluxo

• Ano de defesa: 2023
• Autor(a) principal: Souza, Raquel Gomes de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Citometria de fluxo; Células B; Neoplasias de células B maduras; HLDA9
• Link de acesso: https://repositorio.unifesp.br/handle/11600/67388

Introduction: Flow cytometry is widely used in the evaluation of lymphoproliferative neoplasms, allowing for diagnosis, classification, and monitoring of treatment effectiveness. However, some mature B-cell neoplasms exhibit important immunophenotypic overlap, making correct classification difficult. The 9th International Workshop on Human Leukocyte Differentiation Antigens (HLDA9) described eighteen new molecules expressed in B lymphocytes. Knowledge of the expression pattern of these new proteins can provide important information for diagnostic evaluation, detection of aberrant immunophenotypes for minimal residual disease study, and development of new therapies with targeted monoclonal antibodies. However, data on the expression of these new markers in mature B-cell neoplasms are still scarce in the literature. Objectives: To characterize the expression of the new B-cell markers described in HLDA9 during B lymphocyte differentiation in normal samples and evaluate their role in the diagnosis and classification of mature B-cell neoplasms, including the evaluation of CD5-positive mature B-cell neoplasms, hairy cell leukemia, and plasma cell and lymphoplasmacytic neoplasms. Materials and methods: The expression of CD210a, CD215, CD270, CD307a, CD307b, CD307c, CD307d, CD351, CD352, CD353, CD354, CD355, CD357, CD358, CD360, CD361, CD362, and CD363 antigens was evaluated in B lymphocyte subpopulations in peripheral blood and bone marrow of healthy individuals and patients with mature B-cell neoplasms by eight-color multiparameter flow cytometry. Results: In normal samples, CD307b, CD361 and CD352 antigens showed moderate to high expression in B lymphocytes, while CD361 and CD352 antigens were strongly expressed in plasma cells. The other markers showed low expression intensity. Univariate analysis identified differential expression of CD307a, CD353, CD361, CD352, CD360, and CD354 antigens between normal mature B-cell subpopulations. Patients with CLL showed lower expression intensity of CD270, CD352, and CD351 antigens, while exhibiting hyperexpression of CD307a, CD307b, and CD307c antigens. In patients with LCM, CD270, CD352, CD307a, and CD307b antigens showed weaker expression, while CD353 antigen exhibited a slight increase in expression. In HCL, CD210a, CD352, and CD361 antigens showed hyperexpression in neoplastic B cells. Regarding plasma cells, the CD352 antigen showed significant differences between the studied groups. The analysis also revealed the usefulness of CD361 antigen in identifying anomalous plasma cells after treatment with daratumumab. Conclusion: Our results show that the new HLDA9 markers can be useful in identifying neoplastic B cells and characterizing anomalous immunophenotypes. The application of these markers can help distinguish between different subtypes of mature B-cell neoplasms, contributing to improving the diagnosis and treatment of these patients.