Cellular and vascular manifestations of cell-mediated immunity

Significance of lymphocytes and blood vessel changes for edema formation in polyradiculoneuritis

Human sural nerve biopsies of eight cases with acute, subacute and chronic polyradiculoneuritis were studied by means of immunohistochemistry to characterize the inflammatory infiltrates. In addition, the structural changes of the endoneurial blood vessels were examined by electron microscopy, since both factors are likely to contribute to disturbances of the blood-nerve barrier. By use of six monoclonal antibodies, it was shown that the inflammatory infiltrates in cases with more acute polyradiculoneuritis are predominantly recruited by Leu 3a- and Leu 4-positive T lymphocytes. In more chronic polyradiculoneuritis beside of few Leu 3a-positive and Leu 4-positive T lymphocytes also B cells occurred. Leu M3-positive macrophages were detected in all cases with fluoride myelin degeneration. Since immunoreactivity for antigens of the HLA-D-locus (Leu-HLA-DR and Leu 10) were present on the infiltrating mononuclear cells, it can be postulated that they represent active and immunocompetent cells. Ultrastructurally, the amount of pinocytotic vesicles in the endothelial cells of the endoneurial blood vessels was increased. Moreover, a prominent folding of the luminal and abluminal surface of vascular endothelial cells and diminution of the intercellular tight junctions were observed. These findings appear suitable to explain the increased leakage of serum proteins across the blood-nerve barrier in polyradiculoneuritis sharing general features of cell-mediated immunity.

The pathogenesis of vascular changes in erythema nodosum-like lesions of Behçet's syndrome: an electron microscopic study

The probable sequence of microvascular changes affecting endothelial cells in erythema nodosum-like lesions was examined by electron microscopy in 18 patients with typical Behçet's syndrome. Dark endothelial cells in the superficial and deep dermis exhibited degeneration with contraction changes. Consequently, degenerated endothelial cells showed nuclear and cytoplasmic condensation, vacuolization in the cytoplasm, and rich ribosomes. Moreover, blood vessels which were enveloped by cuffs of lymphocytes simultaneously exhibited both endothelial cell hypertrophy and endothelial cell necrosis. The implied associations between perivascular lymphocytic cuffs and blood vessels exhibiting endothelial cell alterations indicate that microvascular changes in erythema nodosum-like lesions may be closely associated with the delayed-type hypersensitivity reaction.

Studies of the role of mast cells in contact sensitivity responses. Passive transfer of the reaction into mast cell-deficient mice locally reconstituted with cultured mast cells: effect of reserpine on transfer of the reaction with DNP-specific cloned T cells

The role of mast cells in the elicitation of contact sensitivity (CS) responses was evaluated by transferring different aliquots of the same preparations of immune lymph node cells (I-LNC) into naive, genetically mast cell-deficient (WBB6F1-W/Wv or WCB6F1-S1/S1d) mice and the corresponding congenic normal (+/+) mice. We found that the 24-hr CS responses elicited in the recipient mast cell-deficient mice were statistically indistinguishable from those in the congenic +/+ mice according to four different criteria: micrometer measurements of ear swelling, ratios of the weight or [125I]iododeoxyuridine-labeled leukocyte infiltration-associated cpm in challenged and contralateral control ears, and amount of 125I-fibrin deposition. We also transferred I-LNC into WBB6F1-W/Wv mice which, 5 months earlier, had undergone local repair of their mast cell deficiency by the intradermal injection (into the left ear only) of growth factor-dependent cultured mast cells derived from congenic +/+ mice. When 24-hr CS responses were elicited in both ears of these mice, the reactions in the mast cell-reconstituted left ears were similar to those in the mast cell-deficient right ears. We also found that treatment of antigen-specific cloned T cells with reserpine in vitro markedly impaired their ability to transfer reactivity for CS, providing further evidence that reserpine can interfere with the expression of T-cell-mediated responses through effects independent of its action on mast cells.

Neovascularization and coronary atherosclerotic plaque: cinematographic localization and quantitative histologic analysis

A new technique was developed for analyzing the neovascularization associated with coronary artery atherosclerosis: cinematography during silicone polymer injection of the coronary arteries of fixed and cleared human hearts, followed by histologic analysis in routine and 1-micron-thick, Epon-embedded sections. Twenty-two hearts obtained at autopsy were studied. On the basis of cinematographic findings, individual regions of the coronary arteries were classified as negative, positive, or abundantly positive for neovascularization. Positive and abundantly positive areas, which invariably occurred in segments exhibiting changes of atherosclerosis, contained numerous small vessels in the adventitia and outer media (4.7 +/- 1.5 and 9.8 +/- 1.3 [SE] vessel profiles/artery cross-section in positive and abundantly positive areas, versus 1.0 +/- 0.6 in negative regions). Abundantly positive areas, which occurred in coronary artery segments demonstrating the most extensive atherosclerotic change, contained numerous small vessels in the inner media or in the plaque itself. Some of these microvessels were in close proximity to mast cells, which represent potentially rich sources of mediators affecting vascular tone and permeability. Vessels were not observed in the inner media or in atherosclerotic plaque in areas designated either positive or negative by cinematography. These findings show how our approach can be used both to define the three-dimensional, in situ configuration of coronary artery neovascularization and to characterize the histology of this process in detail. They also confirm previous work indicating that areas of coronary arteries involved by atherosclerosis frequently exhibit extensive neovascularization.

The effect of IgE-mediated mast cell degranulation on the expression of experimental contact sensitivity in the mouse

The effects of mast cell activation/degranulation on the elicitation of contact sensitivity (CS) to oxazolone and dinitrofluorobenzene were investigated. Mice were actively sensitized to oxazolone by epicutaneous painting followed by ear challenge. Passive sensitization to DNFB was induced by intradermal injections of dinitrophenol (DNP)-specific cloned T cells in the ears. Mast cells in the challenged ears were activated in various time periods by inducing a passive cutaneous anaphylaxis reaction where passive sensitization with monoclonal IgE anti-DNP antibodies was followed by iv injection of DNP-BSA. This combination of immediate and delayed-type hypersensitivity reactions resulted in a significant increase of ear swelling without any noticeable effect on cellular infiltration when the contact response was evaluated a short time (3-4 hr) after mast cell activation. The very same results were obtained in naive (unsensitized) mice, indicating that this reaction was nonspecific. However, when the CS reaction was evaluated at its peak, i.e., 24 hr post challenge, mast cell activation that had been induced 0.5-11 hr after ear challenge did not have any significant effect on both swelling and cellular infiltration when the latter was evaluated by a radiometric assay. We conclude that in these systems mast cell activation/degranulation makes little or no contribution to the modulation of T-cell activity.

Immunohistology of adenolymphoma (Warthin's tumour): evidence for a role of vascularization in the organization of the lympho-epithelial structure

The epithelial, vascular and lymphoid components present in two cases of adenolymphoma (Warthin's tumour) were characterized by immunohistochemistry on frozen sections. Epithelial cells were positive for cytokeratin and keratin and were in close contact with numerous factor VIII related antigen-positive capillary vessels, running parallel to the epithelial basement membrane. The capillary vessels were in communication with high endothelial post-capillary venules which were often lined by HLA-DR-positive endothelial cells. The lymphoid tissue was organized in B-cell and T-cell areas. The B-cell areas consisted of B4+/To15+ B-lymphocytes admixed with DRC-1-positive follicular dendritic reticulum cells. The T-cell areas were mainly populated by T11+/T3+/T4+ lymphocytes admixed with some S-100+/HLA-DR+ interdigitating reticulum cells. Plasma cells and T8+ lymphocytes were more numerous in the proximity of the epithelium. Leu-M3+/PAM-1+ macrophages were scattered singly in the T-cell areas or were arranged in sinus-like structures around the epithelial cysts. The epithelial basement membrane, the vascular membrane and the fibrillar reticular stroma of the lymphoid tissue were immunoreactive for laminin and type IV collagen. The possibility is discussed that the accumulation of lymphoid tissue in Warthin's tumour is modulated by the epithelial cells, perhaps through their ability to organize a peculiar pattern of vascularization.