Flow Cytometry Applications for Blood Immunophenotyping
Immunophenotyping refers to the process of detecting expressed protein markers to identify and quantify specific subsets of cells within a heterogeneous population. Flow cytometry is the most common method of immunophenotyping suspended cell samples and is particularly useful for analyzing whole peripheral blood (WPB) samples for a variety of diseases.
Researchers have used flow cytometry to analyze WPB since the Coulter Counter was introduced in 1953. Since then, improvements to cytometer instrumentation and antibody development have allowed for blood immunophenotyping to detect a continually growing list of diseases with increased precision and speed. Here we examine some of the most important applications of flow cytometry for immunophenotyping of blood samples.
Complete Blood Count
A Complete Blood Count is a common clinical blood panel used to give information about white blood cells (WBC), red blood cells (RBC), and platelets. Specifically, physicians can order tests of WBC differential (ratio of WBC types) and RBC indices (average RBC size and hemoglobin concentrations), and hematocrit (percentage of WPB made of RBCs). Clinical labs typically use automated flow cytometry analyzer instruments for high throughput testing of patient samples.
WPB immunophenotyping is used when screening blood cancers leukemia and lymphoma. Detection of clusters of differentiation (CD) or other protein markers can help clinicians diagnose cancerous cells and distinguish between different cancer types.
A few common blood cancer markers include Syndecan 1, CD33, CD52, Bcl-2, CD20, TNF-alpha, and TAL1. The NIH-NCI offers a more comprehensive list of tumor markers, here.
Beyond cancer, blood immunophenotyping can also be used to detect protein or genetic markers for many different diseases. Some examples include allergy biomarkers associated with childhood asthma, inflammation markers linked to depression, and autoimmune markers for fibromyalgia, osteoarthritis, systemic lupus erythematosus, multiple sclerosis, and diabetes. New markers are continually being discovered as researchers better understand the underlying genomic and biological factors associated with various diseases.
One-Tube Multicolor Flow Cytometry Assay
Researchers at the University Hospital Erlangen recently developed a predefined multicolor immunofluorescence panel to determine a patient’s “comprehensive immune status”. Their assay employs 15 fluorescent antibodies to identify 20 clinically relevant immune cell subsets and three common activation markers and can be run on any three lasers, 10-color flow cytometer.
WPB immunophenotyping is a useful tool for both researchers and clinicians seeking detailed information about a blood sample. Advances in both technology and our understanding of disease mechanisms have allowed blood immunophenotyping assays to detect many diseases with speed and accuracy. Continued development of simple but adaptable multicolor fluorescent assays will help to grow the importance of WBP immunophenotyping.