B cells and aging: a historical perspective

The belief that aging thwarts disease resistance has existed for millennia. Indeed, ancient medical teachings posited that aging itself was a disease, although these notions were discarded by the early 19th century and replaced by constructs envisioning aging as a gradual, uneven degradation of normal physiological functions that in turn fosters an increased risk of illness and frailty. Progress toward a mechanistic understanding of this relationship awaited acceptance of the germ theory of disease,1 combined with an appreciation for immune recognition as the primary basis for natural and acquired protection.2–4 Once in place, these concepts naturally converged to establish a linkage between aging and altered immune function. Thus, as the field of immunology has advanced, probing how aging impacts the immune system has enjoyed avid and sustained interest. This collection centers on investigations of this relationship, particularly regarding the B lymphocyte lineage, and these introductory remarks overview their underlying constructs and chronology.