Natural antibodies in childhood: Development, individual stability, and injury effect indicate a contribution to immune memory

Natural, often autoreactive antibodies are present in normal sera in large quantity and show alterations in specificity in diverse pathological situat ions. They have, however, usually not been studied longitudinally. Here we investigated some representative serum reactivities of natural antibodies i n 67 normal children and 10 with injury during childhood, followed up for 3 years. Normal children showed an individually characteristic and relativel y stable level of most IgM, IgG, and IgA reactivities when measured with EL ISA by reference to a standard. injured children showed some very rapidly e nhanced reactivities within 3 days after trauma, which thereafter slowly di minished over years before coming back to a normal level. This period excee ds by far the lifetime of antibodies and plasma cells. We conclude that nat ural antibodies contribute to the establishment and maintenance of immune m emory in a manner that is distinct from classical immune reactions.