Increased frequency (12%) of circulating chronic lymphocytic leukemia-like B-cell clones in healthy subjects using a...

Area of Science:

• Hematology
• Immunology
• Flow Cytometry

Background:

• Monoclonal B-cell lymphocytosis (MBL) is defined as < 5 x 10^9/L circulating monoclonal B cells in healthy individuals.
• Previous studies using less sensitive methods reported MBL in 5-7% of adults.

Purpose of the Study:

• To investigate the frequency of circulating monoclonal B cells in healthy adults over 40 using a highly sensitive 8-color flow cytometry.
• To determine if MBL incidence increases with age.

Main Methods:

• Analysis of 608 healthy subjects aged >40 years with normal blood counts.
• Utilized a highly sensitive 8-color flow cytometry for detection of monoclonal B cells.
• Systematic screening for peripheral blood leukocyte counts > 5 x 10^6/L.

Main Results:

• Monoclonal B cells, including chronic lymphocytic leukemia (CLL)-like B cells, were detected in 12% of subjects.
• The frequency of MBL was significantly higher than previously reported.
• MBL incidence increased with age, with 62% of cases below the detection limit of older techniques (<0.01%).

Conclusions:

• The prevalence of MBL in healthy adults over 40 is higher than previously estimated.
• Highly sensitive flow cytometry is crucial for accurate MBL detection.
• Age is a significant factor in the incidence of MBL.