AbstractWe studied 134 “healthy persons” with no past history of any serious or latent diseases, and observed differences in their 25 lymphocyte subsets by conducting two‐color analyses using 12 useful combinations of dye‐labeled monoclonal antibodies.CD4+Leu8+cells and CD25+CD3+cells were significantly higher in males than in females, whereas CD4+Leu8−cells and CD23+CD19+cells were significantly higher in females. In comparison of the 25 lymphocyte subsets among four age groups, CD45RA−CD4+cells and CDw29+CD4+cells significantly increased with age, and CD8+CD11b−cells and CD57−CD8+cells significantly decreased with age.In females, helper T cells significantly increased and helper inducer T cells increased, while cytotoxic T cells decreased with age. These are important findings that should be considered in studies of immune function and autoimmune disorders. © 1994