T-cell independent transfer of organized granuloma formation.

A direct role for delayed hypersensitivity in organized granuloma formation has been emphasized in the literature, but some clinical and experimental studies have suggested a more complicated relationship. In order to further evaluate T-cell function in cutaneous granulomatous inflammation, hepatic granulomas isolated from athymic mice with schistosomiasis were grafted into the skin of athymic and euthymic mice. Granulomas developed in athymic mice, as seen previously after transplantation of euthymic hepatic granulomas, indicating that granulomas develop in the skin without T-cell function. However, the granulomas in athymic mice skin were smaller and lacked eosinophils and mast cells, whereas the athymic mouse granulomas grafted in euthymic mice skin were larger, better organized, and associated with tissue eosinophilia. These findings suggest that granuloma initiation itself is T-cell independent, but that T-cell participation enhances the granulomatous reaction.