Immunophenotyping using flow cytometry

Immunophenotyping is a term applied to the technique of identifying the specific lineage (“families”) of cells through the use of antibodies that detect antigens or markers expressed on the cell-surface/within the cell (hence “immuno”).

Some of these molecules are lineage-specific, meaning that they are found only on one specific cell type, whereas others can be found on various cells. Depending on which molecule will be detected, this method can be used with cells generated from blood as well as from tissues.

With regards to the expression of the molecules on/in cells, it is important to understand that this is a very dynamic process, which is impacted on by conditions within a host, such as inflammation, occurrence of cancer types, infectious diseases etc.

Thus, immunophenotyping is typically used for the following conditions involving hematopoietic cells:

• Differentiation between B and T cell lymphoid neoplasms, i.e. lymphoma, chronic lymphocytic leukemia
• Prognostication in lymphoma, e.g. a T helper phenotype (CD4-positive) has been associated with a poorer prognosis in peripheral T cell lymphoma, decreased MHCII expression has been associated with a poorer prognosis in peripheral B cell lymphoma
• Differentiation between acute myeloid and lymphoid leukemia
• Differentiation between reactive and neoplastic expansions of lymphocytes
• Identification of specific subsets of lymphocytes, e.g. helper:cytotoxic T cell ratio
• Assessment of antibiotic effect in terms of acute infections, such as sepsis
• Assessment of anti-inflammatory drug effects, such as in conditions of rheumatoid arthritis

Thus, we are currently developing, in collaboration with our clinical and pathology services, a set of routine diagnostic markers that allow for a faster assessment of a situation.