Immunophenotypic

Immunophenotypic describes the phenotype of cells as defined by the expression of specific antigens detected by immunophenotyping. Immunophenotyping uses monoclonal antibodies directed against surface or intracellular markers to characterize cell lineages and maturation states.

The most common platforms are flow cytometry and immunohistochemistry. Flow cytometry analyzes thousands of cells per second using fluorescently labeled antibodies to profile multiple markers simultaneously; immunohistochemistry visualizes marker expression within tissue sections, preserving histologic context.

Applications include classification of hematologic malignancies, such as identifying B- or T-lineage leukemias and differentiating lymphomas, and distinguishing malignant from reactive processes. Immunophenotyping also supports diagnosis, prognosis, and treatment planning, and it is used to monitor minimal residual disease and immune reconstitution after therapy.

In solid tumors, immunophenotyping by immunohistochemistry or other antibody-based assays helps determine lineage and origin when morphology is inconclusive, aiding diagnostic categorization and therapeutic decisions.

Markers are often reported as CD antigens or lineage-specific proteins; panels are tailored to the clinical question and disease category. Interpretation requires expertise and standardized approaches, and results can be influenced by sample quality, fixation, and prior therapy, which may affect antigen expression.

Guidelines from the World Health Organization and international consortia provide criteria that integrate immunophenotypic data with genetic and morphologic findings for disease classification and reporting.