Dynamics and mechanism of the sarcoidal granuloma. Detecting T cell subsets, non-T cells, and immunoglobulins in biopsies at varying intervals of Kveim-Siltzbach test sites.

Punch biopsies of K-S test sites were studied by the use of monoclonal antibodies for the presence of T cells, T cell subsets, B cells, IgG, IgM, IgA, and kappa and lambda chains by an indirect and direct immunoperoxidase technique. A total of 10 biopsies were performed at intervals ranging from 6 hr to 34 days. Results revealed that at 6 hr there was an influx of T cells, predominantly helper cells, at the injection site, followed by an infiltration of monocytes, an infiltration that was maximal at 48 hr. By day 7 there was a marked increase in the number of T lymphocytes, predominantly helper cells, and a few persistent monocytes were seen. By day 12 there was evidence of granuloma formation with the appearance of some epithelioid cells and a few giant cells. These cells, along with helper T cells, were seen to have progressively increased in number when the confluent granulomas on the day 34 biopsies were studied. Epithelioid cells, however, did not show any reactivity with Leu-M3 monoclonal antibody, which stained the majority of peripheral blood monocytes. B cells were rarely present; immunoglobulins were absent in all biopsies. It was concluded that the evolution of the sarcoidal granuloma in response to K-S antigen is a purely cell-mediated phenomenon. Helper-inducer T cells appear to play a dominant role in its evolution and maintenance. Lack of reactivity of epithelioid and giant cells with Leu-M3 monoclonal antibody indicates either a different lineage from monocytes or a change in their phenotype.