The possibilities of the diagnostics of the CD5-positive B-lymphoproliferative disorders

CD5+ B-lymphoproliferative disorders represent a significant group of the defined diagnostic entities within the framework of the WHO

classification of mature B-cell neoplasms. The pathological presence of CD5 antigen is an important diagnostic feature because of the minor

expression of CD5 on normal B-lymphocytes. The laboratory diagnostics of the CD5+ B-lymphoproliferative disorders is multidisciplinary and

it comprises the morphological methods (cytology, histology), the methods of immunophenotyping (immunohistochemistry, flow cytometry)

and the cytogenetic and molecular cytogenetic methods. Based on the morphological features, the immunophenotype and the genetic profile,

three groups of the CD5+ B-lymphoproliferative diseases can be recognized: the entities with the bright CD5 expression in a major part of

cases (chronic lymphocytic leukaemia, small lymphocytic lymphoma, mantle cell lymphoma), the entities with the CD5 expression in a significant

minor part of cases (B-prolymphocytic leukaemia, splenic marginal zone lymphoma) and the entities with rare CD5 expression (other types of

marginal zone lymphomas, diffuse large B-cell lymphoma, follicular lymphoma, lymphoplasmacytic lymphoma, Burkitt lymphoma).

Keywords: CD5, B-lymphoproliferative disorder, cytology, histology, immunophenotype, cytogenetics