Lymphocyte populations in human lymph nodes. Alterations in CD4+ CD25+ T regulatory cell phenotype and T-cell receptor Vbeta repertoire

Here we provide a description of lymphocyte populations in human lymph nodes (LN) with a special emphasis on the CD4+ lymphocyte population constitutively expressing CD25 at a high level and endowed with immunoregulatory properties [T regulatory (Treg) cells]. Lymph nodes were analysed by multicolour flow cytometry in parallel with correspondent peripheral blood (PB). Immunomagnetically purified Treg cells were tested for anergy and suppressive activity in a CD3/T-cell receptor (TCR)-driven proliferation assay. Compared to PB, there was a reduced T/B lymphocyte ratio in LN. Both LN and PB contained a similar proportion of CD4+ lymphocytes but, conversely, CD8+ lymphocytes were less represented in PB, with a consequent increase in the ratio of CD4+/CD8+ natural killer cells were