Memory B cell subpopulations in the aged.
The literature on immunosenescence has focused mainly on T cell impairment. With the aim of gaining insight into B cell immunosenescence, the authors investigated the serum IgD levels in 24 young and 21 old people and analyzed their relationship with the number of CD19+CD27+ memory cells. Serum IgD were quantified by the use of radial immunodiffusion and the lymphocyte population CD19+CD27+ was identified by a FACScan flow cytometer. Serum IgD levels were significantly lower (p < 0.0001) in old subjects, and the percentage of CD19+CD27+ lymphocytes were significantly increased (p = 0.01) in old subjects. Finally, a significant negative correlation was found (p = 0.01) between serum concentrations of IgD and CD19+CD27+. The present results show that the levels of IgD are negatively age-related to the amount of B memory cells. This suggests that the B repertoire available to respond to new antigenic challenges is decreased in the elderly. In fact, many memory IgD- B cells fill immunologic space, and the number of naïve IgD+ B cells is dramatically decreased. Therefore, these preliminary results suggest that a decrease of naïve IgD+CD27- B cells and a concomitant increase of memory IgD-CD27+ B cells could represent hallmarks of B immunosenescence, might provide biomarkers related to the lifespan of humans, and could be useful for the evaluation of antiaging treatments.
Colonna-Romano
Giuseppina
G
Gruppo di Studio sull'Immunosenescenza, Dipartimento di Biopatologia e Metodologie Biomediche, University of Palermo, Palermo, Italy. gcolonna@unipa.it
Aquino
Alessandra
A
Bulati
Matteo
M
Di Lorenzo
Gabriele
G
Listì
Florinda
F
Vitello
Salvatore
S
Lio
Domenico
D
Candore
Giuseppina
G
Clesi
Gioacchino
G
Caruso
Calogero
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D018941:Antigens, CD19 / Q000032:analysis; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D005260:Female; D006801:Humans; D007072:Immunoglobulin D / Q000097:blood; D007156:Immunologic Memory; D008297:Male; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000032:analysis
D018941:Antigens, CD19; D007072:Immunoglobulin D; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7