Pulmonary vasculitis (Wegener's granulomatosis). Immunohistochemical study of T and B cell markers

A case of pulmonary vasculitis (Wegener's granulomatosis) is reported in which immunoperoxidase studies demonstrated that the vascular lymphoid infiltrates were composed predominantly of T cells and monocytes. Occasional T cells, B cells and monocytes were identified in the alveolar septa. IgG, IgA, IgM, and C3 were not identified in pulmonary vessels, septa, or alveoli. These findings suggest that cellular rather than humoral-immune mechanisms predominate in pulmonary vasculitis.