title: A study of serum immunoglobulin levels in elderly persons that provides new insights into B cell immunosenescence.
abstract: The literature on immunosenescence has focused mainly on T cell impairment. With the aim of gaining insight into B cell immunosenescence, we investigated the serum immunoglobulin levels in a cohort of 166 subjects (20-106 years). Serum IgG (and IgG subclasses) were quantified by the nephelometric technique, IgE by CAP system fluorescence enzyme immunoassay, and IgD by radial immunodiffusion (RID). There was an age-related increase of IgG and IgA; the IgG age-related increase was significant only in men, but IgG1 levels showed an age-related increase both in men and women, whereas IgG3 showed an age-related increase only in men. IgE levels remain unchanged, whereas IgD and IgM serum levels decreased with age; the IgM age-related decrease was significant only in women, likely due to the relatively small sample of aged men. Thus, in the elderly the B cell repertoire available to respond to new antigenic challenge is decreased. A lot of memory IgD- B cells are filling immunological space and the amount of naïve IgD+ B cells is dramatically decreased. This shift away from a population of predominantly naïve B cells obviously reflects the influences of cumulative exposure to foreign pathogens over time. These age-dependent B cell changes indicate that advanced age is a condition characterized by lack of clonotypic immune response to new extracellular pathogens. In any event, the increase of memory B cells and the loss of naïve B cells, as measured by serum IgD levels, could represent hallmarks of immunosenescence and could provide useful biomarkers possibly related to the life span of humans.
authors.affiliation: Gruppo di Studio sull'Immunosenescenza, Dipartimento di Biopatologia e Metodologie Biomediche, Corso Tukory 211, 90134 Palermo, Italy.
authors.forename: Florinda
authors.initials: F
authors.lastname: Listì
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Candore
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Modica
authors.forename: Mariangela
authors.initials: M
authors.lastname: Russo
authors.forename: Gabriele
authors.initials: G
authors.lastname: Di Lorenzo
authors.forename: Maria
authors.initials: M
authors.lastname: Esposito-Pellitteri
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Colonna-Romano
authors.forename: Alessandra
authors.initials: A
authors.lastname: Aquino
authors.forename: Matteo
authors.initials: M
authors.lastname: Bulati
authors.forename: Domenico
authors.initials: D
authors.lastname: Lio
authors.forename: Claudio
authors.initials: C
authors.lastname: Franceschi
authors.forename: Calogero
authors.initials: C
authors.lastname: Caruso
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000097:blood*; D007156:Immunologic Memory; D008136:Longevity / Q000276:immunology*; D008297:Male
chemical_list: D015415:Biomarkers; D007136:Immunoglobulins