Microvascular deposition of complement membrane attack complex in dermatomyositis

We examined the role of the complement system in the pathogenesis of dermatomyositis. Using an antibody against the neoantigens of the terminal C5b-9 membrane attack complex, we performed immunocytochemical studies that localized this complex to the intramuscular microvasculature (arterioles and capillaries) of muscle biopsy specimens from 10 of 12 patients (83 percent) with childhood dermatomyositis and 5 of 19 patients (26 percent) with adult dermatomyositis. Fifty-two control specimens, including 14 from patients with polymyositis and 12 from patients with denervation atrophy (a condition known to be associated with necrotic capillaries), showed no deposition of membrane attack complex in the microvasculature. These findings indicate that the complement system is deposited, bound, and activated to completion within the intramuscular microvasculature of patients with dermatomyositis. In addition to providing further evidence for the presence of vasculopathy in dermatomyositis, these findings suggest a primary role for complement in mediating vessel injury in the disease, particularly in its childhood form.

Isolated arteritis of the epididymis

The clinical, histological, and immunohistochemical features of two cases of apparently isolated arteritis of the epididymis are presented. The aetiology and pathogenesis of the condition are discussed. Immunoglobulin and complement were shown in the acute arterial lesions, but this is not conclusive evidence that isolated arteritis is either an immune complex disease or a forme fruste of polyarteritis nodosa.

Further evidence of the development of delayed-type autoimmunity against arterial vessel-wall antigens following acute hypertensive damage to arterial vessels in rats

Acute hypertensive damage to arterial vessels was induced by intravenous injections of hypertension. The in vitro immunological method of the agarose migration technique was used for demonstration of delayed-type autoimmunity against arterial vessel-wall antigens following the damage of the arterial vessels. By means of this technique it was demonstrated that the migration indices from the rats with induced hypertension differed significantly from the control rats, P less than 0.005. This means that an autoimmunity of the delayed type had developed after the hypertensive damage to the arterial vessels. The autoimmunity was tissue specific.

Immunofluorescent studies of the endometrial arteries in the first trimester of pregnancy

Endometrial spiral arteries from curetted endometrium of 110 first-trimester pregnancies were studied by immunofluorescent (IF) technics using antibodies against human G, M, and A immunoglobulins, C3, C4, and fibrinogen. Heavy deposition of C3 in the arterial walls was found in 16 (14.6%) cases. Immunoglobulins, C4, and fibrinogen were found in only a few cases, and their staining was weak and not considered in this study. There was also a statistically significant (P less than 0.01) higher deposition of C3 in arterial walls of primipara (14 of 52), as compared to multipara (2 of 58). The possible mechanisms of C3 deposition and the importance of the higher incidence of this deposition in primipara are discussed in relation to suggested immunologic pathogenetic alterations in preeclampsia.

Immunohistochemical findings in acute atherosis associated with intrauterine growth retardation

Lesions of acute atherosis in 23 placentas from pregnancies complicated by fetal growth retardation (less than tenth percentile) were studied by an immunoperoxidase staining. Twelve of them were from normotensive pregnancies, ten complicated by pregnancy induced hypertension, and the remaining associated with systemic lupus erythematosus. Twenty-three placentas with physiological changes of the spiral arteries corresponding to normal pregnancies served as controls. Six of the cases complicated by fetal growth retardation showed absence of physiological changes in basal decidua. Massive intramural granular deposits of IgM, a smaller amount of C3 and C1q, and slight deposits of IgA and IgG were found in vessels with acute atherosis. No intramural deposition of immunoglobulins or complement was observed in vessels with or without physiological changes. The presence of granular deposits of immunoglobulins and complement within the vessel walls with acute atherosis may be related to an immunological disorder, probably mediated by immune complexes.

Accumulation of IgG and complement factor C3 in human arterial endothelium and atherosclerotic lesions

Endothelial injury is associated with an intracellular accumulation of IgG. Fluorescent antibodies were used to detect IgG and complement factor C3 in biopsies of human arteries. Both proteins were found in endothelial cells with signs of injury, in normal and atherosclerotic arteries. Rhodamine-conjugated anti-IgG and FITC-conjugated anti-C3 were used to count the number of IgG- and C3-containing endothelial cells in non-atherosclerotic cystic arteries. IgG was found in 26% of the cells, with C3 in 38% of the IgG-containing cells. Both IgG and C3 were also observed in the subendothelial intima of cystic arteries and in atherosclerotic lesions of iliac and femoral arteries. The accumulation of IgG and C3 in injured endothelium and in atherosclerotic lesions could be of importance for complement-mediated tissue destruction and for the attraction and activation of white blood cells.

Abdominal pain associated with IgA nephropathy. Possible mechanism

A 36-year-old man presented with IgA nephropathy (Berger's disease) and acute abdominal pain. Surgical biopsy of the ileum revealed deposits of IgA, C3, and fibrin in segments of the wall of submucosal arteries. The immune deposits appeared associated with areas of fibrinoid necrosis. These findings support the hypothesis that Berger's disease is a systemic disease, and provide a possible explanation for the abdominal pain associated with IgA nephropathy.

Electron-dense deposits in the renal arterioles of two patients with hypersensitivity vasculitis

Immune complex deposition in the vessel wall is presumed to be the major pathogenetic mechanism leading to hypersensitivity vasculitis. Despite this, histologic evidence of vascular immune complex deposition such as that provided by electron-dense deposits has been reported only rarely in dermal vessels and never in visceral organs. The cases of two patients with hypersensitivity vasculitis affecting primarily the skin and the kidney are reported. Clinical renal involvement was manifested by proteinuria, hematuria, and a moderate increase in serum creatinine in one case. Renal biopsy showed minimal glomerular changes in one patient and focal necrotizing glomerulitis in the other. The arterioles appeared normal on light microscopic examination. However, obvious electron-dense deposits in the arteriolar wall could be demonstrated electron microscopically in both cases. This observation lends strong support to the theory of immune-complex-mediated vascular damage as the main pathophysiologic mechanism in vasculitis with visceral involvement.

[Vascular factors in the pathogenesis of pre-eclampsia: recent findings]

Normal, rigid and fibrotic utero-placental arteries are resistant to the action of circulating vaso-motor substances. In contrast, the persistence and the hyperplasia of smooth muscle fibres result in a reduced flow in the intervillous compartment and a sensitivity of the vessels to vaso-constrictor substances. These lesions, which develop after the twentieth week, provide the necessary conditions for the subsequent development of the characteristic vicious cycles of eclampsia.

Increased factor VIII related antigen in cerebral thrombosis

Changes of Factor VIII related antigen (FVIIIR:Ag) were measured in patients with cerebral thrombosis on day 1-15 (125 cases), 16-45 (acute reaction phase, 70 cases), and during 1.5-5 months (recovery phase, 29 cases) after onset of the disease. FVIIIR:Ag was significantly (P less than 0.001) increased in both acute and recovery phase as compared to 108 healthy controls, although slightly decreased in recovery than in acute phase. The persistently high FVIIIR:Ag levels in acute phase are unlikely to be caused by the so-called acute phase reaction but are probably due to increased synthesis and endothelial changes in atherosclerotic lesions releasing FVIIIR:Ag from its endothelial pool. It suggested that increased FVIIIR:Ag mainly reflects the degree of vascular involvement and it may be used as a marker (or indicator) of arterial endothelial injury in patients with cerebral thrombosis.

Cytomegalovirus antigen within human arterial smooth muscle cells

Arterial tissues from carotid artery plaques or from punch-biopsy samples of uninvolved areas of the aorta were removed from 132 patients with atherosclerosis during blood-vessel surgery. Cells morphologically identical to smooth muscle cells were cultured from 26 to 126 plaque samples and from 6 of 6 punch-biopsy samples. Immunofluorescence tests of these cells showed that more than 25% of the cell cultures from both types of sample contained antigens of human cytomegalovirus (CMV) but not of herpes simplex virus type 1 or type 2. Replicating CMV was not detected by electron microscopy in the antigen-positive cells, suggesting that the artery walls may be a site of CMV latency.

Cellular cytotoxicity against canine endothelial cells. Analysis of determinants recognized by CTL

A method is described which permits culture of both arterial and venous canine endothelial cells. Cell-mediated cytotoxicity against cultured endothelial cells has been studied. A 51Cr-release assay was used to detect CTL generated in MLC. Both arterial and venous endothelial cells are lysed by CTL specifically. Cold target inhibition experiments have been performed to analyse the CTL-recognized antigens on arterial and venous endothelial cells. Different antigens are recognized by CTL on venous endothelial cells and PHA-blasts; it is possible that CTL recognize venous endothelial cells through class II antigens or E-M antigens. Arterial endothelial cells and PHA-blasts share CTL-recognized antigens.

Autoantibodies in thromboangiitis obliterans (Buerger's disease)

Autoantibodies, organ and non-organ specific, were studied in 10 patients of thromboangiitis obliterans by immunofluorescence technique and compared with age matched controls without peripheral vascular disease and patients of other peripheral vascular diseases. Organ specific autoantibodies (various classes of immunoglobulins IgM, IgG, IgA) and C3 component were observed in the diseased vessels of thromboangiitis obliterans. Antibodies, antiarterial, were present in the sera of these patients. Among the non-organ specific antibodies (ANA and AMA), only ANA were found in the sera of patients. Presence of autoantibodies in patients of thromboangiitis obliterans strongly point out of that probably this disease entity is an autoimmune disorder.

An immunoperoxidase study of senile cerebral amyloidosis with pathogenetic considerations

Samples of human cerebral cortex were obtained from twelve autopsied patients with Alzheimer's disease or "normal" aging. Rabbit or goat anti-human antisera to the following plasma proteins: IgG, F(ab')2, Fc, kappa and lambda light chains, IgM, IgA, fibrinogen, albumin, C3, lysozyme, haptoglobin, macroglobulin, and microglobulin; antibodies to the following intracellular proteins: glial fibrillary acidic (GFA) protein, filamin, actin, non-muscle myosin, tubulin, cholinergic vesicle proteins, and neurofilament (NF) proteins were utilized in the immunoglobulin peroxidase bridge. Amyloid cores of classical or perivascular plaques and dyshoric angiopathy exhibited a strong reaction for intact IgG and for both of its light chains, moderate reactions for lysozyme, fibrinogen, albumin and IgA, and weak reactions for IgM, C3, Fc, F(ab')2, haptoglobin, macroglobulin and microglobulin. Antibodies to all three NF proteins, individually and pooled, stained dyshoric and plaque amyloid, while antibodies to other intracellular proteins did not. The coronae of classical plaques and many primitive plaques stained for GFA, but inconsistently for IgG, both light chains, lysozyme, actin, tubulin, and NF proteins. Affected vessels of three patients with Congophilic angiopathy were reactive for all plasma proteins (especially IgG, fibrinogen, and albumin) and for NF proteins. NF staining in Congophilic blood vessels, although variable, revealed a peripheral or adventitial distribution, whereas plasma proteins tended to be localized in the media of the vessel wall. The distributions of Congo red and NF positivity were often identical. Both NF and Congo red staining was sensitive to oxidation. Isolated NF proteins were Congophilic and capable of displaying apple-green birefringence. A hypothesis concerning the role of NF proteins in senile cerebral amyloid is presented.

Induction of chronic arterial hypertension in rats by repeated transient hypertensive rises in blood pressure. Possible pathogenetic role of delayed hypersensitivity against arteries and arterioles

Repeated transient rises in blood pressure to hypertensive levels were induced by intravenous injections of angiotensin once or twice weekly. This procedure induced chronic arterial hypertension in five of fourteen rats (36%) within 4-6 weeks of starting the injections. Intracutaneous tests using homogenized common carotid arteries and histological examination of the kidneys gave support to the hypothesis that the transient rises in blood pressure to hypertensive levels resulted in a delayed hypersensitivity (DHS) reaction against components in small arteries and arterioles. This DHS reaction seemed to be responsible for an increased permeability of arterial vessels to plasma components causing exudative thickening of the walls of small arteries and arterioles and thereby narrowing of their lumina. When the lumina of small arteries and arterioles are narrowed, peripheral resistance to blood flow increases, and arterial hypertension results.

Immunofluorescent studies of the uteroplacental arteries in normal pregnancy

Immunofluorescent studies were performed on placental bed biopsies from 27 normal pregnancies. Uteroplacental arteries were present in 26 of the 27 biopsies and all showed deposition of fibrin in relation to the fibrinoid layer within the vessel wall; 12 also showed deposition of C3. Interstitial fibrinoid deposits also stained positively with fibrin. There was no deposition of immunoglobulins within the arterial changes nor in association with intramural or interstitial trophoblast. This study indicates that fibrin is a significant contributor to the fibrinoid layer within the uteroplacental arteries, and suggests that the presence of bound C3 is due to the activation of the complement system by fibrinogenesis. There was no evidence that the humoral immune response was involved in the aetiology of the physiological changes in the uteroplacental arteries.

Immunological changes in patients with previous malignant essential hypertension

Increased T-lymphocyte reactivity against human arterial antigen was significantly more common in a group of 20 patients with previously malignant essential hypertension than in matched control subjects. Serum-levels of IgG and IgM and the prevalence of autoantibodies were also significantly higher in the patients. It is suggested that these changes, whether primary or secondary, may contribute to or aggravate the vascular damage in this condition and are therefore of pathogenetic importance.

Immunological aspects of atheroma: a review

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The role of hepatitis B surface antigen in the pathogenesis of glomerulopathies

The frequency of hepatitis B surface antigen (HBsAg) has been studied in the sera and renal biopsies of 276 patients with various forms of glomerulonephritis (GN), the nephrotic syndrome and other nephropathies. Using a modified Hepanosticon method, HBs antigenemia was detected in 32 of 196 patients (16.3%) with immune complex (IC) GN and the nephrotic syndrome. Indirect immunofluorescence revealed HBsAg in 33 renal biopsy tissue specimens (16.8%). HBsAg was found in the sera of four of the 80 remaining patients with other renal diseases (5%), and in the renal biopsy tissues of another four (5%). Antibody against HBsAg could only be demonstrated in the serum of one glomerulonephritic patient. The sera of 18,799 normal blood donors were used as controls; of these 186 (0.99%) had positive tests for HBsAg. It is concluded that, in some patients with GN and the nephrotic syndrome, HBsAg-containing IC may be implicated in the development and/or progression of the disease.

Cellular immunity in polymyalgia rheumatica and giant cell arteritis: lack of response to muscle or artery homogenates

Peripheral blood lymphocyte functions were evaluated in 20 patients with active polymyalgia rheumatica (PMR) and/or giant cell arteritis (GCA) by determining the percent of E-rosette-forming cells and by measuring the uptake of tritiated thymidine by peripheral blood lymphocytes after exposure to common infectious antigens and to homogenates of homologous and heterologous artery, muscle, and elastin. Although lymphocytes from patients with PMR and/or GCA were stimulated slightly by artery and muscle homogenates, no differences in lymphocyte responses were found when the results were compared with 22 normal controls and 16 patients with rheumatoid arthritis. The hypothesis that GCA results from a cellular immune reaction to normal or diseased arterial wall antigens is not supported by these studies.

Comparison of the immunologic reactions of arterial transplants in the arterial system and of venous transplants in the venous system using inbred strains of rats

(1) Arterial transplants used as arterial replacements induce sensitization of the recipient in the weakly as well as in the strongly allogeneic systems (afferent limb). (2) Venous transplants used as venous replacements induce sensitization of the recipient (afferent limb). (3) Arterial transplants show increasingly severe rejection reactions paralleling the degree of immunogenetic difference (efferent limb). (4) Veins transplanted as venous replacements are tolerated even in the strongly allogeneic systems (efferent limb).

Vasectomy increases the severity of diet-induced atherosclerosis in Macaca fascicularis

Diet-induced atherosclerosis developed more extensively in vasectomized cynomolgus monkeys (Macaca fascicularis) than in sham-vasectomized control monkeys fed the same diet. The effect was most pronounced in the abdominal aortas, carotid arteries, distal segments of the coronary arteries, and intracranial cerebral arteries. Antibodies to sperm developed in all vasectomized monkeys, and complement and immunoglobulins were associated with atherosclerotic plaques in some of the vasectomized animals. The immunological response to sperm antigens that often accompanies vasectomy may exacerbate atherosclerosis.

[Comparative immunological and morphological studies following transplantation of fresh and preserved allogeneic vein and artery segments in rat experiments]

Immunological and morphological investigations were carried out on immunogenetically different strain combinations of inbred rats following transplantation of fresh allogeneic and implantation of formalin preserved vein segments. In contrast to vital allogeneic transplants, which evoke an immunological response depending on immunogenetic difference between donor and recipient, there is neither humoral nor cellular immunological response after implantation of formalin fixed vein segments. Therefore, from an immunological standpoint, strongly allogeneic vein implants preserved by formalin can be used for replacement of arteries.

Immunopathology of the renal vascular lesion of progressive systemic sclerosis (scleroderma)

Patients with progressive systemic sclerosis (PSS, scleroderma) exhibit a variety of immunologic abnormalities. To verify whether the renal vascular lesions of such patients might be mediated by an immunologic mechanism, kidney tissues of 16 patients with PSS were investigated by means of fluorescence, light, and electron microscopy; elution of tissue-bound antibody; and fixation of heterologous (guinea pig) complement. Controls consisted of 12 nonsclerodermatous patients with similar levels of hypertension with no evidence of associated immunologic abnormalities. Diffuse vascular deposits of immunoglobulins (predominantly IgM) and/or complement (predominantly Clq) were found in all 16 patients with PSS. These deposits were bound to the intima of intralobular and arcuate arteries which, by light microscopy, often exhibited typical fibromucinous alterations. Elution of antibody and heterologous complement fixation studies suggested that such reactants may represent the interaction of complement-fixing antibody and antigen. Electron microscopies studies demonstrated abundant fibrillar and ground substance material in the arterial intima but features of deposited (circulating) immune complexes were not found. By contrast, in the hypertensive (control) group, deposits of immunoglobulin (s) and/or complement were rare and, when present, were mostly confined to the arterioles. As judged by the results of elution and heterologous complement fixation, these arteriolar deposits appeared to represent trapped rather than specifically bound serum proteins. The possible signficance of these findings are discussed in relation to immunologic mechanisms which might be implicated in the pathogenesis of the renal vascular disease of PSS.