Abstract
Epithelioid cell granulomas are consisted of epithelioid cells in the center with surrounding lymphocytic rim, and several data which have been accumulated suggest that the epithelioid cells arised from macrophages rather than those from lymphocytes. Macrophages may divide in the tissue, while the precursor cells in the bone marrow may mature and become monocytes, and they are transported by blood stream to the connective tissue of the whole body, then transformed into macrophages under further maturation and cell division. Most of macrophages in the inflammatory changes seem to originate from precursor cells in the bone marrow.
Macrophages are the main actors of many granulomas, whereas lymphocytes may have some role to initiate and to control the granuloma formation, and both cells have close interrelation during these phenomena. In the case of tuberculous granulomas, it has been clearly shown that both the antigen-antibody reaction and coexistence of Wax D are the necessary factors for the formation of epithelioid cell granulomas, although the questions whether adjuvant activity or hardly digestable high-molecular substance is important for Wax D and how the cellular and humoral immunity correlate to the granuloma formation remains to be dissolved. In tuberculin reaction only a few sensitized lymphocytes were found in the reaction site, and more over, epithelioid cell granulomas could be formed in the T-cell deficient animals.
From the review of the literature in this field, epithelioid cell granulomas may be tentatively classified as follows:
I. With immunological events
(a) and coexistence of Wax D or other similar glucolipid
(b) under particulated antigen which persisted for a long time in tissue
(c) other unknown conditions
II. Without obvious immunological event.
