Lymphocyte subsets in human tonsils: the effect of age and infection

The aim of the present study was to determine the effect of repeated tonsillitis on the development of lymphocyte subsets in the tonsils and among peripheral blood lymphocytes (PBL) of children. Subsets of T- and B cells were analyzed in the tonsils and in PBL of patients undergoing tonsillectomy for idiopathic tonsillar hypertrophy, recurrent tonsillitis, or tonsillar hypertrophy and tonsillitis. The majority of the CD4+ cells in the tonsils displayed the CD45RO+ phenotype, while the majority of those in the PBL displayed the CD45RA+ phenotype. Likewise, the proportion of CD45RO+CD8+ cells was higher in the tonsils than among PBL. The proportion of CD4 cells expressing the CD45RO marker increased with age among PBL, but not in the tonsils. B cells, detected by their CD19, CD20, and CD21 markers, were three times more abundant in the tonsils than in the PBL. The proportion of CD38+ cells showed a negative correlation with age, both in the tonsils and among PBL. Among PBL a striking age-related reduction was seen in the proportion of CD19+, CD21+ and CD38+CD21+ B cells. In contrast, in the tonsils age-related changes could be detected only in the proportion of CD21+CD38+ cells. No difference among patients with various clinical diagnoses was detectable in any of the T- and B cell subsets in the tonsils and PBL. Thus, lymphocyte subsets evolve independently in the tonsils and peripheral blood, with the repeated antigenic challenge of tonsillar lymphocytes not influencing circulating memory cells.