Buerger's disease is a rather rare pathology characterized by nonatherogenic vascular lesion associated with the inflammation in the intima of the vessel and the thrombus formation. Most often the pathological process affects small and medium caliber arteries. Vascular occlusion can lead to tissue ischemia and the trophic ulcers, and cause the extremity amputation. The disorder pathogenesis has not been fully explored. Literature data indicate that the disease development may be associated with autoimmune processes. The paper presents the results of immunohistochemical study of the material obtained after amputation of the lower extremity in a patient diagnosed with Buerger's disease. The patient had a 15-year tobacco smoking experience. In the inflammatory cell infiltrates around the affected vessels, lymphocytes with CD4, CD8 antigens and IgG immunoglobulin deposits were found, which could be considered as the evidence of the autoimmune mechanisms’ involvment. Immunohistochemical reactions with markers of NK cells CD56 and the central component of the C3d complement system were negative. The results of the study suggest that the key role is played by helper and suppressor T lymphocytes, as well as by humoral antibodies of the IgG class.