Changes of human B and B-1a peripheral blood lymphocytes with age.

In 2057 consecutive subjects admitted to the Department of Pathology, Section of Immunology of the Verona University Hospital, CD19+ and CD5/CD19 double positive cells were determined to assess the behaviour of total peripheral B-lymphocytes and B-1a (CD5+) compartments in humans during aging. We show that the absolute number of total B lymphocytes increases about three-fold from the baseline conditions in the first year of life and progressively decreases until adult age. A slower decrease was detected from the adult age onwards. A similar behaviour has been observed within the B-1a subset of B-lymphocytes, although the decrease after the adult age seems more pronounced. Possible physiological explanations and/or implications for the disease states are taken into account.