Cellular and humoral immune responses to vascular components were studied in 10 patients with thromboangiitis obliterans (TAO), including 3 in the mild stage of the disease and 7 in the active or severe stage. In this study the authors used the following vascular components: collagen Types I, III, IV, and V; elastin; and laminin. The cell-mediate reactivity (CMR) to these proteins was measured with an antigen-specific proliferation of peripheral mononuclear cells and evaluated by the stimulation index (SI), which is the ratio of thymidine incorporation in the presence and in the absence of antigen. The humoral immunologic response (HIR) to these vascular components was measured by an enzyme-linked immunosorbent assay (ELISA) and evaluated by the optical density (OD) index, which is the ratio of optical density (OD) in the patients' serum to that in the healthy male controls' serum. The stimulation index of collagen Types I and IV was significantly higher in patients with TAO than in healthy controls (p < 0.02). CMR to collagen Type V, elastin, and laminin was high in patients with active or severe TAO as well. However, similar statistical differences in mild TAO did not exist in the CMR. The OD index in collagen Types I, IV, and V was statistically higher in the patients than in the healthy controls (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)