title: Age-related differences in human palatine tonsillar B cell subsets and immunoglobulin isotypes.
abstract: The tonsils provide defense of the upper aerodigestive tract against pathogens. Although long known to undergo functional changes with age, the precise changes occurring within tonsillar B cell populations remain undefined. In the present study, we investigated age-related changes in palatine tonsillar B cell subsets and immunoglobulin (Ig) isotypes. Palatine tonsils were obtained from forty-two tonsillectomy patients without tonsillitis who were divided into three groups: young children (4-9 years), adolescents (10-19 years), and adults (20-60 years). Tonsillar B cells were then analyzed by flow cytometry. Using expression of CD38 and IgD to define B cell subsets, we found that the frequency of germinal center (GC) B cells in the tonsils was significantly higher, and the frequency of memory B cells lower, in young children as compared to adolescents and adults. Within the GC B cell subsets, adults had a higher frequency of IgA(+) cells and a lower frequency of IgM(+) cells as compared to individuals in the younger age groups. Moreover, young children had a higher frequency of IgG(+) cells in the GC B cell subsets than did individuals in the older age groups. We also observed an abundance of IgM(+) cells among memory B cells and plasmablasts in young children and IgA(+) cells in adults. In summary, the proportion of GC B cells in palatine tonsillar B cells decreases with age, while the proportion of memory B cells increases with age. In addition, Ig isotypes in tonsils preferentially switch from IgM to IgA as individuals age.
authors.affiliation: Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon, 305-701, Republic of Korea.
authors.forename: Jino
authors.initials: J
authors.lastname: Lee
authors.affiliation: Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon, 305-701, Republic of Korea.|Department of Otorhinolaryngology, Gyeongsang National University Hospital, Jinju, 660-702, Republic of Korea.
authors.forename: Dong-Yeop
authors.initials: DY
authors.lastname: Chang
authors.affiliation: Department of Otorhinolaryngology, Gyeongsang National University Hospital, Jinju, 660-702, Republic of Korea.
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon, 305-701, Republic of Korea.
authors.forename: Yoon Seok
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Otorhinolaryngology, Gyeongsang National University Hospital, Jinju, 660-702, Republic of Korea.
authors.forename: Sea-Yuong
authors.initials: SY
authors.lastname: Jeon
authors.affiliation: Department of Internal Medicine and Clinical Oncology, University of Bari Medical School, Bari, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Racanelli
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Boramae Medical Center, Seoul National University College of Medicine, Seoul, 156-707, Republic of Korea. kicubi@daum.net.
authors.forename: Dae Woo
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, KAIST, Daejeon, 305-701, Republic of Korea. ecshin@kaist.ac.kr.
authors.forename: Eui-Cheol
authors.initials: EC
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018858:Germinal Center / Q000276:immunology; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014066:Palatine Tonsil / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
chemical_list: D007132:Immunoglobulin Isotypes
keywords: Age; B cell; Immunoglobulin; Isotype; Subset; Tonsil