Human Lymphocyte Membrane Immunoglobulin as a Reflection of Maturation

Peripheral blood lymphocytes can be divided into two subpopulations on the basis of surface antigens and membrane receptors. It is generally well recognized that lymphocytes that contain readily detectable surface or membrane-bound immunoglobulin (M-Ig)3 are B lymphocytes (1). The published data on the normal range of B lymphocytes in various studies have not taken into account the possibility of age-related changes in the number and class distribution of human B lymphocytes (2–12). This study was designed to investigate both the number and class distribution of M-Ig on human B lymphocytes obtained from normal subjects in the 1st through the 8th decade of life. The following points are demonstrated: 1) Children (ages 1 to 10) have B lymphocytes bearing IgM (M-IgM) in significantly greater numbers than adults ages 21 to 90 (t = 6.03, p < 0.001). 2) Lymphocytes bearing IgG (M-IgG) in children appear decreased when compared to adults (t = 2.37, p < 0.02). 3) Circulating lymphocytes bearing M-IgM decrease with age (correlation coefficient = -0.62). 4) Adults have M-Ig κ:λ ratio >2 whereas the κ:λ ratio in children equals 1 (t - 2.43, p < 0.02).