S-100 protein-positive dendritic cells and CD34-positive dendritic interstitial cells in palatine tonsils.

Dendritic cells (DCs) are effective antigen-presenting cells and have been shown to mature from precursor CD34-positive stromal cells (dendritic interstitial cells, DICs) or monocytes. To gain insight into the local immune response in human tonsils, we investigated immunohistochemically the presence of DCs and DICs in 17 non-hyperplastic and 13 hyperplastic tonsils. Dense infiltrates of S-100-positive DCs were noted in the majority of hyperplastic tonsils, while there were fewer in non-hyperplastic tonsils. DICs were noted specifically at the periphery in the dense hemi-capsule cap that separates the tonsil from the underlying muscle. In addition, their small number suggests that the accumulation of S-100 dendritic cells in hyperplastic palatine tonsils is achieved through migration from other sites rather than through maturation from precursors locally.