Interleukin-4 deficiency enhances Th1 responses and crescentic glomerulonephritis in mice

Evidence suggests that crescentic glomerulonephritis (GN) is due to T helper cell 1 (Th1) directed delayed-type hypersensitivity (DTH)-like injury. As endogenous interleukin (IL)-4, (the pivotal cytokine in Th2 responses) may attenuate Th1 responses in this disease, we compared the development of crescentic GN, induced by a planted antigen, in mice genetically deficient in IL-4 (IL-4-/-) with disease in normal mice (IL-4+/+). IL-4-/- mice developed more severe GN with increased renal impairment (CCr 35 +/- 7 microliters/min vs. 133 +/- 14 microliters/min, P < 0.002) and crescent formation (55.7 +/- 8.4% vs. 4.9 +/- 1.2%, P < 0.002). This was associated with increased glomerular fibrin deposition, glomerular CD4+ T cell infiltration and macrophage recruitment. Systemically, IL-4-/- mice showed an increased antigen specific Th1 response indicated by increased skin DTH, and increased IgG3 and IgG2b. Decreased IgG1 levels indicated a reduced Th2 response. These results demonstrate a protective role for endogenous IL-4 in crescentic GN. They show that IL-4 deficiency promotes crescentic glomerular injury and amplifies local and systemic Th1 responses. They support the hypothesis that crescent formation results from Th1 immune responses to antigens in the glomerulus.

Antiinflammatory effect of lipocortin 1 in experimental arthritis

The glucocorticoid-induced antiinflammatory protein lipocortin 1 is present in arthritic synovium but its ability to regulate joint inflammation has not previously been studied. We investigated the role of lipocortin 1 in the antiinflammatory activity of glucocorticoids in an acute arthritis model induced by intraarticular injection of carrageenan. Compared to control joints (0.09 +/- 0.08 x 10(6) synovial fluid cell count), carrageenan injected joints exhibited marked infiltration of PMN (10.2 +/- 0.7 x 10(6), p < 0.001). Both intraperitoneal (1.0 mg/kg) and intraarticular administration (5 micrograms) of dexamethasone (DEX) significantly suppressed arthritis severity (p < 0.001 and 0.005, respectively), and the effects of DEX were significantly prevented by intra-articular injection of antilipocortin 1 mAb (p < 0.05). Carrageenan arthritis was also significantly inhibited by intraarticular administration of the N-terminal lipocortin 1 peptide Ac2-26 at doses of 1 or 2 mg/kg (p < 0.01). Intraarticular injection antilipocortin 1 mAb in the absence of DEX also significantly exacerbated arthritis severity (p < 0.005). In vitro treatment of PMN with DEX was associated with significant inhibition of phagocytosis (p < 0.005) and reactive oxygen species (ROS) generation (p < 0.001). Antilipocortin 1 mAb significantly reduced the inhibitory effects of DEX (p < 0.01 and 0.005, respectively). These results demonstrate that lipocortin 1 mediates the effects of exogenous glucocorticoids on neutrophil migration in carrageenan-induced acute arthritis, exerts an endogenous antiinflammatory influence, and mediates glucocorticoid inhibition of neutrophil activation.

Interleukin-4 and interleukin-10 attenuate established crescentic glomerulonephritis in mice

Crescentic glomerulonephritis (GN) has immunopathological features of delayed type hypersensitivity (DTH) and results from a T helper cell 1 (Th1) dependent immune response. The current study examined the capacity of Th2 cytokines, interleukin (IL)-4 and IL-10, to alter the outcome of crescentic GN, after injury is established. Sensitized, control treated mice developed crescentic GN with functional renal injury (117 +/- 20 microliters/min, normal mouse 182 +/- 8 microliters/min, P < 0.05) 10 days after an i.v. dose of sheep anti-mouse glomerular basement membrane globulin. Combined treatment with IL-4 and IL-10 starting three days after initiation of disease significantly reduced glomerular crescent formation (5.3 +/- 3.2%, control treatment 23.3 +/- 6.4%, P < 0.02) and preserved renal function (165 +/- 15 microliters/min, P = 0.57 compared to normal mice). Treatment with IL-4 alone did not reduce crescent formation or protect renal function. Mice treated with IL-10 showed trends to decreased crescent formation and preservation of renal function. In all cytokine treated groups, the accumulation of effectors of glomerular injury (CD4+ positive T cells, macrophages and fibrin) was reduced, with the combination treatment having the greatest effect. Administration of Th2 cytokines, IL-4 and IL-10 to mice with established GN attenuates the development of glomerular crescent formation and protects renal function.

Th2 responses induce humorally mediated injury in experimental anti-glomerular basement membrane glomerulonephritis

Acute autologous phase anti-glomerular basement membrane glomerulonephritis was compared in Th1-prone (C57BL/6) and Th2-prone (BALB/c) mice. Sensitized BALB/c mice, given a subnephritogenic intravenous dose of anti-mouse glomerular basement membrane globulin, developed acute glomerulonephritis characterized by marked proteinuria and glomerular deposition of mouse immunoglobulin and complement. A significant glomerular neutrophil influx was observed, but few T cells and macrophages were present. C57BL/6 mice, given the same dose of disease-inducing globulin, also developed acute glomerulonephritis, although their proteinuria was significantly less. Glomerular deposition of mouse immunoglobulin and complement and the influx of neutrophils were also significantly less than in BALB/c mice. However, their glomerular accumulation of macrophages and T cells was significantly greater. Complement depletion attenuated neutrophil influx and proteinuria in BALB/c mice but did not affect T cell or macrophage accumulation or proteinuria in C57BL/6 mice. CD4+ T cell depletion significantly reduced glomerular macrophage, T cell influx, and proteinuria in C57BL/6 mice, but had no effect on proteinuria or neutrophil influx in BALB/c mice. Thus, immune responses to planted glomerular antigens in Th2-prone mice induce acute injury as a result of antibody deposition, complement activation, and neutrophil influx, whereas immune responses to the same antigen in Th1-prone mice induce delayed-type hypersensitivity-like lesions in affected glomeruli.

Mechanisms of T cell-induced glomerular injury in anti-glomerular basement membrane (GBM) glomerulonephritis in rats

The effector mechanisms of T cell-dependent acute glomerular injury were studied in autologous phase anti-GBM glomerulonephritis (GN) in rats. Acute proliferative GN was induced in sensitized rats by a subnephritogenic dose of sheep anti-rat GBM antibody. Injury was manifested by proteinuria and glomerular leucocyte infiltration composed predominantly of macrophages but also CD4+ and CD8+ T cells. T cell depletion, using an anti-CD5 MoAb, demonstrated that glomerular leucocyte infiltration and proteinuria were T cell-dependent. Inhibition of T helper cell function using an anti-CD4 MoAb prevented proteinuria and glomerular macrophage and CD4+ T cell influx, but not accumulation of CD8+ T cells. Depletion of CD8+ T cells also prevented proteinuria and the influx of macrophages and CD8+ T cells, but not accumulation of CD4+ T cells. Macrophage depletion, using micro-encapsulated clodronate, prevented proteinuria and glomerular macrophage infiltration, but not the accumulation of CD4+ or CD8+ T cells, indicating that macrophages are the common cellular effectors for both CD4 and CD8 T cell-dependent injury. Evidence for cytotoxic mechanisms of injury (increased numbers of apoptotic cells or accumulation of natural killer (NK) cells in glomeruli) could not be demonstrated. These data suggest that acute glomerular injury in anti-GBM GN is the result of macrophage recruitment, which is dependent on both CD4 and CD8 T cells, and that direct T cell-mediated injury (cellular cytotoxicity) is not involved.

Suppression of adjuvant arthritis and synovial macrophage inducible nitric oxide by N-iminoethyl-L-ornithine, a nitric oxide synthase inhibitor

Nitric oxide (NO.) is a pro-inflammatory effector molecule in certain inflammatory diseases, including arthritis. We investigated the production of NO. by adjuvant arthritis (AA) synovial macrophages, and studied the effects of a NO. synthase inhibitor. N-iminoethyl-L-ornithine (L-NIO). Compared to control rats, rats treated with L-NIO in vivo exhibited significantly lower articular index (p < 0.05), paw volume (p < 0.05), and synovial fluid cell count (p < 0.05). No effect on cutaneous delayed-type hypersensitivity to the disease-initiating antigen was observed. Inducible NO. synthase (iNOS) was detected in AA synovial macrophages, and cultured AA synovial macrophage iNOS levels were increased by a factor of 138 +/- 17% (p < 0.01) by 1 microgram/ml LPS in vitro. Constitutive NO. production by AA synovial macrophages (43 +/- 1 nmol/10(5) cells/24 h) was significantly inhibited by 10 nM L-NIO in vitro (32 +/- 0.5, p < 0.01). NO. production induced by 1 microgram/ml LPS (48 +/- 2) was also decreased by L-NIO (39 +/- 2, p < 0.05). In vivo L-NIO treatment also inhibited alveolar macrophage NO. production (p < 0.05). The ability of L-NIO to decrease iNOS-mediated synovial macrophage NO. production and inhibit the clinical parameters of AA implicate macrophage-derived NO. in the pathogenesis of this disease.

Plasminogen and plasminogen activators protect against renal injury in crescentic glomerulonephritis

The plasminogen/plasmin system has the potential to affect the outcome of inflammatory diseases by regulating accumulation of fibrin and other matrix proteins. In human and experimental crescentic glomerulonephritis (GN), fibrin is an important mediator of glomerular injury and renal impairment. Glomerular deposition of matrix proteins is a feature of progressive disease. To study the role of plasminogen and plasminogen activators in the development of inflammatory glomerular injury, GN was induced in mice in which the genes for these proteins had been disrupted by homologous recombination. Deficiency of plasminogen or combined deficiency of tissue type plasminogen activator (tPA) and urokinase type plasminogen activator (uPA) was associated with severe functional and histological exacerbation of glomerular injury. Deficiency of tPA, the predominant plasminogen activator expressed in glomeruli, also exacerbated disease. uPA deficiency reduced glomerular macrophage infiltration and did not significantly exacerbate disease. uPA receptor deficiency did not effect the expression of GN. These studies demonstrate that plasminogen plays an important role in protecting the glomerulus from acute inflammatory injury and that tPA is the major protective plasminogen activator.

Antibody independent crescentic glomerulonephritis in mu chain deficient mice

The hypothesis that crescent formation in glomerulonephritis (GN) is a delayed type hypersensitivity (DTH)-like lesion, not dependent on a humoral immune response, was addressed using mice with deletion of the mu immunoglobulin heavy chain gene (mu chain deficient mice). Homozygous mu chain deficient mice do not develop mature B cells or produce immunoglobulin, but have intact cell mediated immunity. GN was induced in sensitized mice by a subnephritogenic dose of sheep anti-mouse GBM globulin. Heterozygous mice (mu chain +/-) demonstrated normal antibody and DTH responses to sheep globulin and developed a proliferative GN with proteinuria (6.4 +/- 1.4 mg/24 hr), renal impairment (serum creatinine 32.6 +/- 3.3 mumol/liter) and crescents in 33 +/- 24% of glomeruli, when this antigen was planted in their glomeruli. This lesion was demonstrated to be T cell dependent by in vivo T cell depletion. Homozygous mu chain deficient mice (-/-) also developed proliferative GN, histologically indistinguishable from +/- mice. Proteinuria (3.8 +/- 1.0 mg/24 hr), renal impairment (serum creatinine 24.5 +/- 3.4 mumol/liter) and crescent formation (29 +/- 2% of glomeruli) were no different from =/- mice. Mouse immunoglobulin was absent in their serum and glomeruli, however, cutaneous DTH to sheep globulin was identical to heterozygous mice. These results demonstrate that glomerular crescent formation and injury can occur independent of a humoral immune response to planted glomerular antigen and without glomerular deposition of autologous antibody. This strongly supports the hypothesis that crescent formation is a manifestation of DTH.

Tissue factor initiates glomerular fibrin deposition and promotes major histocompatibility complex class II expression in crescentic glomerulonephritis

Increased glomerular tissue factor (TF) expression is associated with glomerular fibrin deposition and renal failure in human and experimental crescentic glomerulonephritis (GN). However, the in vivo functional contribution of TF to the development of glomerular fibrin deposition, crescent formation, and renal failure in GN has not been established. The contribution of TF to fibrin deposition and renal injury was studied in a rabbit model of crescentic GN in which glomerular macrophage infiltration, augmented TF expression, and fibrin deposition are prominent. Administration of anti-TF antibody inhibited glomerular TF activity in nephritic glomeruli by 96%, without affecting macrophage accumulation or systemic indices of coagulation. Anti-TF antibody significantly reduced glomerular fibrin deposition (fibrin scores, 0.43 +/- 0.10 (treated) and 1.40 +/- 0.19 (control); P < 0.0005), crescent formation (0.33 +/- 0.05 (treated) and 1.0 +/- 0.06 (control); P < 0.0005), and development of renal failure (serum creatinine, 168 +/- 22 mumol/l (treated) and 267 +/- 35 mumol/l (control); P < 0.04). This was associated with significant reduction in proteinuria (1189 +/- 277 mg/24 hours (treated) and 2060 +/- 336 mg/24 hours (control); P < 0.03) and expression of MHC class II antigen in glomeruli (1.25 +/- 0.41 (treated) and 2.83 +/- 0.53 (control); P < 0.03) and in tubules and interstitial areas. These data demonstrate that TF is the major in vivo initiator of fibrin deposition in crescentic GN. The reduction in proteinuria and glomerular major histocompatibility class II antigen expression by TF inhibition suggests that TF may also activate other mediators that contribute to glomerular injury.

Anti-neutrophil monoclonal antibody therapy inhibits the development of adjuvant arthritis

The aim of this study was to determine the contribution of neutrophils to adjuvant arthritis (AA) by in vivo depletion of peripheral blood neutrophils. Specific anti-neutrophil MoAb, RP3 (10 mg), or a control antibody was given twice daily on days 8-11 after injection of Mycobacterium tuberculosis in inbred male Sprague-Dawley rats. RP3 treatment inhibited the neutrophil leukocytosis associated with AA (3.3 +/- 0.6 x 10(3)/mm3 versus 21.2 +/- 6.9 x 10(3)/mm3; P<0.001). On day 12, control animals exhibited severe arthritis as assessed by articular index (AI) (9.2 +/- 1.3), increase in paw volume (149.3 +/- 10.6%), and synovial fluid (SF) cell count (5.3 +/- 0.5 x 10(5)). RP3 treatment significantly reduced AI (1 +/- 0.1; P<0.001), paw volume (103.6 +/- 5.8%; P<0.001) and SF cells (0.6 +/- 0.1 x 10(5); P<0.001) without affecting cutaneous DTH (treated 0.6 +/- 0.1 mm change in thickness, control 0.8 +/- 0.2 mm; NS). Additional experiments demonstrated that CD4+ cell depletion but not decomplementation inhibited AA development and synovial neutrophil accumulation. Depletion of circulating neutrophils prevented joint inflammation and synovial leucocyte influx in AA, suggesting a pivotal role for neutrophils in the effector phase of AA. Inhibition of neutrophil accumulation by CD4+ cell depletion and not by decomplementation suggests that neutrophil accumulation in AA is T cell-dependent.

Immune modulation with interleukin-4 and interleukin-10 prevents crescent formation and glomerular injury in experimental glomerulonephritis

Crescentic glomerulonephritis (GN) demonstrates immunopathological features of a T helper (Th)1-directed delayed-type hypersensitivity (DTH) response. The capacity of Th2 cytokines to attenuate crescentic glomerular injury in this disease was examined by administering interleukin (IL)-4 and IL-10, singly and in combination. GN was induced by i.v. administration of sheep anti-mouse glomerular basement membrane (GBM) globulin to mice sensitized to sheep globulin 10 days earlier. Treatment (2.5 microg, i.p.) with IL-4, IL-10, or both IL-4 and IL-10 (IL-4 + 10), was started 1 h before sensitization and continued daily until the end of the study (10 days after administration of anti-GBM globulin). Control mice treated with PBS developed GN with glomerular accumulation of T cells and macrophages, crescents in 42.5 +/- 4.5 % of glomeruli (normal 0 %), proteinuria (8.3 +/- 0.9 mg/24 h, normal 0.74 +/- 0.08 mg/24 h, p <0.001) and renal impairment (creatinine clearance [cr/cl]: 93 +/- 12 microl/min, normal 193 +/- 10 microl/min, p < 0.001). Treatment with either IL-4, IL-10, or IL-4 + 10 prevented crescent formation (crescentic glomeruli: 0.8 +/- 0.5, 1.2 +/- 0.9, and 1.4 +/- 1.0 %, respectively, all p < 0.01 compared to control) and attenuated proteinuria (3.6 +/- 1.0, 2.2 +/- 0.5, and 2.9 +/- 0.5 mg/24 h, respectively, all p < 0.01 compared to control). IL-4 + 10 prevented development of renal impairment (cr/cl: 183 +/- 22 microl/min); IL-10 given alone limited the decline in renal function (cr/cl: 150 +/- 20 microl/min), but IL-4 alone did not provide any significant protection (cr/cl: 121 +/- 17 microl/min). All treatments markedly diminished glomerular T cell and macrophage accumulation, reduced interferon-gamma production by splenic T cells, prevented cutaneous DTH to the disease-initiating antigen and reduced antigen-specific immunoglobulin of the IgG2a and IgG3 isotypes. These data demonstrate that crescentic GN and renal impairment can be prevented by administration of Th2 cytokines and that this effect is associated with attenuation of the Th1 response to the disease-initiating antigen.

Th1 responsiveness to nephritogenic antigens determines susceptibility to crescentic glomerulonephritis in mice

The pattern of glomerulonephritis (GN) developing in response to a planted antigen (sheep anti-mouse GBM globulin) was compared in two strains of mice which demonstrated either a predominant Th1 (C57BL/6) or Th2 (BALB/c) response to this antigen. GN was induced with a subnephritogenic i.v. dose of sheep anti-mouse GBM globulin in mice presensitized to sheep globulin. Sensitized C57BL/6 mice showed pronounced cutaneous delayed-type hypersensitivity (DTH) following the challenge with sheep globulin, low titers of circulating anti-sheep globulin antibody and high interferon gamma (IFN-gamma) and low interleukin 4 (IL-4) production by splenic T cells, consistent with a predominant Th1 pattern of immune response. Sensitized BALB/c mice did not develop DTH following cutaneous challenge with sheep globulin, had higher circulating anti-sheep globulin antibody titers, and showed high IL-4 and low IFN gamma production by splenic T cells compared with C57BL/6 mice, consistent with a predominant Th2 response. In C57BL/6 mice, GN developing in response to sheep globulin exhibited a severe crescentic pattern with prominent glomerular T cell and macrophage influx and fibrin deposition. In vivo depletion with a monoclonal anti-CD4 antibody demonstrated that this injury was T helper cell dependent. Treatment with monoclonal anti-mouse IFN gamma antibody significantly reduced glomerular injury and crescent formation and attenuated the cutaneous DTH response. GN induced by the same protocol in BALB/c mice exhibited pronounced glomerular IgG and complement deposition. Crescent formation, fibrin deposition, and glomerular T cell and macrophage infiltration were significantly less than observed in C57BL/6 mice, and injury was not T cell dependent in the effector phase. These data suggest that the pattern of glomerular injury induced by a planted antigen can be determined by the balance of T helper cell subset activation. A Th1 response induces a severe crescentic pattern of GN, which like cutaneous DTH, is T helper cell and IFN gamma dependent.

Renal expression of tissue factor pathway inhibitor and evidence for a role in crescentic glomerulonephritis in rabbits

Tissue factor pathway inhibitor (TFPI) was demonstrated in the kidneys of normal rabbits and in a crescentic model of glomerulonephritis (GN), where fibrin is a key mediator of injury. In normal kidneys, TFPI was expressed in glomeruli, in intrarenal arteries and the interstitial capillary network. Evidence for TFPI synthesis in vivo was provided by in situ demonstration of TFPI mRNA in glomeruli and intrarenal vessels and by biosynthetic labeling of TFPI released from glomeruli in vitro. In fibrin-dependent crescentic GN, glomerular TFPI synthesis and expression was initially decreased (TFPI antigen at 24 h, 7.5 +/- 0.7 ng/10(3) glomeruli; normal, 11.1 +/- 0.9 ng/10(3) glomeruli, P < 0.02) and subsequently returned to normal values. Plasma TFPI levels increased progressively throughout the evolution of disease. In vivo inhibition of TFPI using an anti-TFPI antibody during the development of GN significantly increased glomerular fibrin deposition (GFD) and exacerbated renal impairment. Infusion of recombinant human TFPI significantly reduced development of GFD (fibrin scores, TFPI treated 0.82 +/- 0.11, control 1.49 +/- 0.14, P < 0.01), proteinuria and renal impairment. This data indicates that TFPI is synthesized and expressed in normal glomeruli and is down regulated in the early response to glomerular injury. Endogenous glomerular TFPI and treatment with recombinant TFPI reduces GFD and injury in fibrin dependent GN. TFPI has the potential to be of therapeutic benefit in the management of fibrin dependent human GN.

P-selectin directs T lymphocyte-mediated injury in delayed-type hypersensitivity responses: studies in glomerulonephritis and cutaneous delayed-type hypersensitivity

The role of P-selectin in T-lymphocyte accumulation and injury was studied in delayed-type hypersensitivity (DTH) responses in the skin and glomeruli of rats. Sprague Dawley rats were sensitized to sheep globulin and challenged 5 days later in the skin by subcutaneous injection and simultaneously in glomeruli by intravenous injection of a subnephritogenic dose of sheep anti-rat glomerular basement membrane globulin. This resulted in cutaneous and glomerular T lymphocyte-dependent macrophage influx and injury characteristic of DTH. Up-regulation of P-selectin expression on endothelial cells was observed in both inflammatory lesions. Treatment of rats with anti-CD5 antibody immediately prior to antigen challenge prevented the development of injury as assessed by measurement of proteinuria and skin swelling, as well as local T cell and macrophage accumulation in the glomerulus and in the skin, but did not block up-regulation endothelial cell P-selectin. Treatment with anti-CD4 antibody produced similar results. Blocking P-selectin in vivo with a functionally inhibitory antibody prevented development of proteinuria and skin swelling following antigen challenge. Local accumulation of T cells and macrophages was markedly attenuated in glomeruli and the skin and up-regulation of endothelial cell P-selectin was prevented. These data demonstrate that P-selectin is locally up-regulated on endothelial cells in T cell-dependent glomerular and cutaneous inflammation and suggests a pivotal functional role for P-selectin in local T cell recruitment and subsequent injury in DTH.

Glomerular tissue factor expression in crescentic glomerulonephritis. Correlations between antigen, activity, and mRNA

Correlations between glomerular expression of tissue factor (TF) activity and antigen and cellular localization of TF mRNA was studied in crescentic glomerulonephritis (GN) in rabbits. Glomerular TF activity increased 8.7-fold 24 hours after initiation of GN (234 +/- 49 mU/10(3) glomeruli; normal, 27 +/- 10 mU/10(3) glomeruli; P = 0.003) in association with a 2.1-fold increase in TF antigen (154 +/- 34 ng/10(3) glomeruli; normal, 72 +/- 10 ng/10(3) glomeruli; P = 0.055), early macrophage infiltration, and no significant increase in TF mRNA. At the peak glomerular macrophage infiltration (day 4), TF activity remained augmented (230 +/- 63 mU/10(3) glomeruli) and TF mRNA, colocalized within macrophages, was significantly increased compared with normal (267 +/- 42%; P = 0.001). TF antigen was not increased in glomeruli (114 +/- 17 ng/10(3) glomeruli), although significant urinary excretion of TF antigen was detectable (478 +/- 121 ng/24 hours; normal, < 1 ng/24 hours; P = 0.032). At this time, the M(r) of glomerular TF (49 to 61 kd) was increased compared with TF in normal glomeruli (49 to 58 kd) as a result of increased glycosylation. At day 7, TF activity and antigen within glomeruli had decreased, although urinary excretion of TF antigen and glomerular TF mRNA remained elevated. These studies suggest that early up-regulation of TF activity is largely a result of functional up-regulation of constitutive TF in intrinsic glomerular cells. In more advanced disease, infiltrating macrophages are the major site of TF synthesis. The increased M(r) of glomerular TF, as a result of synthesis of more highly glycosylated protein by macrophages and the shedding of TF into the urine, suggests that substantial turnover of glomerular TF occurs at this stage.

Detection of intracellular lipocortin 1 in human leukocyte subsets

Lipocortin 1, a putative mediator of the anti-inflammatory actions of glucocorticoids, is present intracellularly in a variety of tissues including human peripheral blood leukocytes. We investigated the presence of lipocortin 1 in human leukocyte subsets using permeabilization flow cytometry. Constitutive lipocortin 1 was detected in U937 myelomonocytic leukemia cells, and lipocortin 1 was increased by treatment with PMA or PMA+IFN-gamma (P < 0.05) but not by dexamethasone. Lipocortin 1 was present in all leukocyte subsets except B lymphocytes (CD19/20+, P < 0.001). Lipocortin 1 content was maximal in monocytes and polymorphonuclear neutrophils and least in lymphocytes (P < 0.001). Monocyte lipocortin 1 was strongly associated with surface expression of CD14 and HLA-DR. Among non-B lymphocytes, a range of lipocortin 1 fluorescence was observed. Lipocortin 1 fluorescence was greatest in natural killer cells (CD56+, P < 0.001) and CD57+ cells, but T cell subset markers did not otherwise discriminate variations in lipocortin 1. Induction of lymphocyte proliferation by PHA, anti-CD3, Con A, superantigen, and SAC was not associated with significant shifts in lipocortin 1 content. Dexamethasone (10(-10)-10(-6) M) did not induce increases in PB leukocyte lipocortin 1. We conclude that lipocortin 1 content in human leukocytes varies significantly among phenotypic subsets. This has significance for the investigation of inflammatory disease where certain cell types predominate.

Beta 2 integrin independent neutrophil recruitment and injury in anti-GBM glomerulonephritis in rabbits

The role of the beta 2 integrin cell adhesion molecules (CAM) in directing neutrophil accumulation and injury in acute anti-glomerular basement membrane antibody induced glomerulonephritis (anti-GBM GN) was assessed in rabbits by in vivo inhibition of CD18 dependent neutrophil/endothelial cell interactions using a monoclonal anti-CD18 antibody. Rabbits given horse anti-rabbit GBM antibody developed significant glomerular neutrophil influx (2.9 +/- 0.1 neutrophils per glomerular cross-section [c/gcs], normal 0.1 +/- 0.1 c/gcs, P = 0.002) and proteinuria (1389 +/- 257 mg/16 h, normal 15 +/- 4 mg/16 h, P = 0.0015) after 16 h. Rabbits rendered neutropenic (< 500 neutrophils/microL) by mustine hydrochloride, or complement depleted by cobra venom factor, did not develop glomerular neutrophil accumulation and had markedly reduced proteinuria after anti-GBM antibody, demonstrating complement-induced neutrophil recruitment is a major mechanism of glomerular injury in this model. Anti-CD18 antibody treatment of rabbits developing anti-GBM GN abrogated dermal neutrophil influx in response to intradermal injection of fMLP and zymosan activated serum. Treated rabbits achieved levels of anti-CD18 antibody in their serum which saturated the binding sites on rabbit neutrophils in vitro, and their circulating neutrophils had saturated anti-CD18 antibody binding in vivo. However, glomerular neutrophil influx (3.5 +/- 0.4 c/gcs) and proteinuria (1210 +/- 428 mg/16 h) were both unaffected. Thus, in this model of antibody-initiated complement and neutrophil-dependent glomerular injury, in which neutrophil transmigration across the endothelium is not required, effective functional inhibition of beta 2 integrin CAM in vivo did not reduce glomerular injury or glomerular neutrophil influx. These studies demonstrate that beta 2 integrin CAM are not a requirement for neutrophil accumulation and glomerular injury in anti-GBM GN in rabbits.

Evidence for delayed-type hypersensitivity mechanisms in glomerular crescent formation

The role of CD4-positive T cells in glomerular crescent formation was examined in WKY rats. Glomerulonephritis (GN) was induced by a subnephritogenic intravenous dose of sheep anti-rat GBM antibody in rats previously sensitized to sheep globulin. This resulted in a severe proliferative and crescentic GN, with marked proteinuria [143 +/- 40 mg/24 hr (mean +/- SD), normal 1.6 +/- 0.7 mg/24 hr] and crescent formation involving 59 +/- 8% of glomeruli at day 10 (normal 0%). Humoral immunity to sheep globulin was evident systemically by high titers of circulating anti-sheep globulin and locally by linear deposition of rat immunoglobulin in glomeruli and cell mediated immunity by cutaneous delayed-type hypersensitivity (DTH) to intradermal injection of sheep globulin. Glomerular accumulation of CD5 positive T cells [2.45 +/- 0.21 cells per glomerular cross section (c/gcs), normal 0.18 +/- 0.10 c/gcs], CD4 positive T cells, (1.87 +/- 0.46 c/gcs, normal 0.14 +/- 0.08 c/gcs), and macrophages (22.7 +/- 5.9 c/gcs, normal 0.05 +/- 0.05 c/gcs), together with the appearance of multinucleated giant cells (0.42 +/- 0.15 c/gcs, normal 0 c/gcs) suggested a DTH-like reaction in glomeruli. Sensitized rats given anti-GBM globulin were treated with monoclonal anti-CD5 or anti-CD4 antibodies in a protocol which prevented cutaneous DTH to sheep globulin without altering the humoral immune response. Both treatments significantly reduced glomerular accumulation of CD5 and CD4 positive T cells at day 10. Crescent formation was significantly reduced (CD5 treated, 13 +/- 4% of glomeruli affected; P < 0.001; CD4 treated 13 +/- 3% of glomeruli affected, P < 0.001) compared to rats treated with an isotype-matched irrelevant monoclonal antibody. Glomerular macrophage accumulation, multinucleated giant cell formation and proteinuria were also significantly reduced by both treatments. These studies demonstrate a functional role for CD4 positive T cells as effector cells within glomeruli, separate from their role in humoral immunity, in the development of crescentic GN. The local participation of CD4 positive T cells, macrophages and multinucleated giant cells in crescent formation, and the attenuation of these features by functional T helper cell depletion suggest that local DTH-like mechanisms may contribute to glomerular crescent formation.

A role for P selectin in complement-independent neutrophil-mediated glomerular injury

Neutrophil recruitment and lung injury following complement activation have been demonstrated to be dependent on endothelial expression of P selectin. In anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM GN) in mice, acute glomerular injury results from complement-independent neutrophil accumulation. The signals for neutrophil recruitment in this model are unknown. Expression of P selectin on glomerular endothelium was demonstrated within 30 minutes of administration of anti-GBM antibody to C57/BL10 mice. This was associated with rapid accumulation of neutrophils in glomeruli which peaked at one hour (6.2 +/- 0.5 neutrophils per glomerular cross section [neut/gcs], normal 0.34 +/- 0.06 neut/gcs, P < 0.01) and significant proteinuria after 16 hours (3.6 +/- 0.5 mg/16 hr, control 0.62 +/- 0.13 mg/16 hr, P < 0.01). Complement depletion with cobra venom factor, which reduced serum C3 levels to less than 5% of normal, did not alter expression of P selectin, reduce glomerular neutrophil accumulation (6.7 +/- 0.8 neut/gcs) or proteinuria (3.7 +/- 0.5 mg/16 hr). Platelet depletion also failed to alter glomerular expression of P selectin, neutrophil accumulation or the development of proteinuria. Mice were treated with an affinity purified anti-human P selectin antibody, which cross reacted with mouse P selectin and blocked P selectin-dependent binding of thrombin-activated mouse platelets to HL60 cells and did not bind to mouse neutrophils. Treatment, one hour prior to the administration of anti-GBM antibody, markedly inhibited glomerular neutrophil accumulation (0.94 +/- 0.12 neut/gcs) and prevented proteinuria (1.0 +/- 0.2 mg/16 hr), and did not alter binding of anti-GBM globulin in the kidney. These data strongly suggest that the rapid up-regulation of P selectin expression in glomeruli following binding of anti-GBM antibody is an essential signal for neutrophil recruitment in this complement independent model of glomerular injury.

Glomerular fibrinolytic activity in anti-GBM glomerulonephritis in rabbits

Fibrin is an important mediator of injury in severe proliferative forms of glomerulonephritis (GN). Normal glomeruli express fibrinolytic activity, which may protect against the injurious effects of fibrin deposition. Changes in glomerular fibrinolytic activity (GFA) may play an important role in modulating fibrin accumulation in GN. To study the changes in GFA associated with fibrin deposition in GN, autologous phase anti-glomerular basement antibody initiated GN (anti-GBM GN) was studied in rabbits. Net GFA was significantly reduced in association with glomerular fibrin deposition (1.3 +/- 0.8 ng fibrin lysed/10(3) glomeruli/2 hr, normal 57.1 +/- 25.4 ng fibrin lysed/10(3) glomeruli/2 hr, P < 0.02). Reduced GFA in fibrin associated GN was associated with decreased expression of tissue type plasminogen activator (tPA) and increased expression of plasminogen activator inhibitor type-1 (PAI-1) and glomerular macrophage infiltration. In a fibrin independent model of anti-GBM induced GN (heterologous phase), with equivalent injury (proteinuria), net GFA was increased (174 +/- 64 ng fibrin lysed/10(3) glomeruli/2 hr). This was associated with increased tPA and uPA, and decreased PAI-1 in the absence of significant macrophage infiltration. These studies demonstrate that fibrin deposition in GN is associated with a net reduction of GFA, attributable to reduced expression of plasminogen activators and augmentation of PAI-1. Reduction of GFA may potentiate glomerular fibrin deposition and consequent glomerular injury. The association between glomerular macrophage influx and reduction in GFA suggests that this change may be directed by macrophages.

Tumor necrosis factor production by glomerular macrophages in anti-glomerular basement membrane glomerulonephritis in rabbits

The production of tumor necrosis factor (TNF) by nephritic glomeruli and glomerular macrophages was studied in antiglomerular basement membrane antibody induced glomerulonephritis (anti-GBM GN) in rabbits. Autologous phase injury was associated with glomerular macrophage infiltration and augmented TNF production by isolated nephritic glomeruli (day 8, 1.15 +/- 0.10 ng/10(3) glomeruli/24 hours; normal, 0.01 +/- 0.01 ng/10(3) glomeruli/24 hours; p less than 0.05). In contrast, during the heterologous phase, in which macrophages were not prominent, injury was not associated with augmented glomerular TNF production. Glomerular TNF bioactivity had a molecular weight and isoelectric point consistent with rabbit TNF and was inhibitable by an anti-TNF antibody. TNF was also identified in nephritic glomerular supernatants by Western blotting. Macrophages isolated from glomeruli of rabbits developing autologous phase anti-GBM GN produced significantly more TNF (0.14 +/- 0.02 ng/10(3) macrophages/24 hours) than blood monocytes (0.03 +/- 0.02 ng/10(3) monocytes/24 hours, p less than 0.05) from the same rabbits. Macrophage depletion of rabbits with autologous phase anti-GBM GN significantly reduced proteinuria, prevented glomerular macrophage accumulation, and blocked augmentation of glomerular TNF production. These studies demonstrate the association of glomerular TNF production with the development of glomerular macrophage infiltration and injury in anti-GBM GN and suggest that infiltrating glomerular macrophages are the major source of glomerular TNF.

T lymphocyte participation in acute serum sickness glomerulonephritis in rabbits

The extent and timing of glomerular T lymphocyte infiltration was studied in acute serum sickness (AcSS) glomerulonephritis (GN) in rabbits. AcSS was initiated by a single intravenous injection of bovine serum albumin (BSA). Rabbits developed circulating BSA anti-BSA immune complexes, and rapid immune elimination of the circulating antigen was associated with the deposition of immune complexes in the kidney and the onset of a diffuse endocapillary proliferative GN. On the day of immune elimination (defined as when less than 1% of the injected antigen remained in the circulation), rabbits developed significant proteinuria (98 +/- 36 mg/24 h; normal 14 +/- 1 mg/24 h, P less than 0.01), glomerular macrophage accumulation (44.3 +/- 21.1 macrophages per glomerulus [mac/glom]; normal 0.28 +/- 0.18 mac/glom, P less than 0.01), and a significant glomerular T lymphocyte influx (3.0 +/- 0.9 cells/glomerular cross-section [c/gcs]; normal 0.47 +/- 0.13 c/gcs; P less than 0.005). On the day prior to immune elimination, increased T cells numbers were observed in some rabbits (2.4 +/- 2.1 c/gcs) together with a minor macrophage presence (7.6 +/- 3.6 mac/glom) and minimal proteinuria (17.6 +/- 3 mg/24 h). These studies demonstrate the influx of T lymphocytes together with macrophages at the onset of proteinuria in serum sickness nephritis and are consistent with a role for cell-mediated immunity in the pathogenesis of this lesion.

Acute pulmonary and renal injury after administration of heterologous anti-lung antibodies in the rat. Characterization of ultrastructural binding sites, basement membrane epitopes, and inflammatory mediation systems

Male Sprague-Dawley rats developed acute lung and renal injury after administration of heterologous anti-lung antibody. Both organs demonstrated an increase in protein permeability after antibody binding to basement membrane (BM) antigens (lung permeability index 0.342 +/- 0.009 versus control 0.214 +/- 0.011: p less than 0.05. Urinary protein excretion 5.112 +/- 0.899 mg/hour versus control 0.402 +/- 0.008 mg/hour: p less than 0.01). The threshold value for the development of lung injury was 27.2 +/- 4.8 micrograms of antibody globulin/g of tissue (micrograms/gm). Immunoblot analysis probing with the anti-lung antibody revealed at least one common antigenic determinant (82 to 84 kilodaltons) bound within collagenase-solubilized pulmonary and glomerular BMs. Increasing doses of antibody produced hemorrhagic pneumonitis and diffuse alveolar damage. Immunofluorescence microscopy confirmed linear alveolar and glomerular BM antibody binding. Immunogold electron microscopy allowed precise identification, in intense linear patterns, of BM binding sites within lung and glomeruli. Functional lung injury was prevented by either leukocyte-depletion or complement-depletion (lung permeability index antibody-treated, complement-depleted 0.235 +/- 0.034: both p greater than 0.05 compared with controls). Injury mediation in this acute humoral model of lung damage is both complement- and leukocyte-dependent, as previously described for the renal component of heterologous anti-glomerular BM antibody-induced inflammatory disease.

Measurement of anti-DNA antibodies by ELISA: a comparative study with Crithidia and a Farr assay

One hundred and twenty six sera from 116 patients with systemic lupus erythematosus (SLE) and from 51 control patients were assayed for the presence of anti-DNA antibodies, using a commercial enzyme linked immunosorbent assay (ELISA). Fifty three sera (42%) from SLE patients were positive and a further 13 sera (10%) fell in the 'equivocal' positive range. Three control sera were positive. In a standard 14C DNA Farr assay, 67 sera (53%) from SLE patients were positive. One control serum was weakly positive. There was a good linear correlation between absorption in the ELISA and the 14C DNA binding result (r = 0.73). Results in the ELISA and Farr assays were concordant in 96 of the 126 SLE sera, and 47 of 51 control sera. Sequential sera from a further 6 patients with fluctuating clinical activity of SLE showed similar patterns of change of anti-DNA antibodies in both assays. The ELISA was more sensitive than the Crithidia luciliae immunofluorescence assay which detected 44 positive sera (35%) in the SLE group. These results suggest that this ELISA assay may be a useful alternative to the Crithidia assay or an effective screen prior to testing in the more technically difficult and time consuming Farr assay for the measurement of anti-DNA antibodies.

Glomerular interleukin 1 production is dependent on macrophage infiltration in anti-GBM glomerulonephritis

Both macrophages and glomerular mesangial cells have the potential to synthesize interleukin 1 (IL-1), however, their respective contributions to IL-1 production in anti-GBM glomerulonephritis (GN) are unknown. To address this problem, IL-1 production by glomeruli from rabbits with macrophage-associated anti-GBM GN (passive autologous anti-GBM GN [PAGBMGN]) and macrophage independent (heterologous phase) anti-GBM GN was studied. Macrophage-infiltrated nephritic glomeruli produced IL-1 bioactivity which was inhibitable by an anti-IL-1 antibody, and had a molecular weight consistent with rabbit IL-1. Glomerular IL-1 production in PAGBMGN was markedly augmented (1.43 +/- 0.79 U/10(3) glomeruli [gloms]/24 hr) compared to normal glomeruli (0.13 +/- 0.06 U/10(3) gloms/24 hr, P less than 0.05) or glomeruli from rabbits with macrophage independent GN (0.11 +/- 0.07 U/10(3) gloms/24 hr, P less than 0.05). IL-1 production by glomeruli from leukocyte depleted rabbits with PAGBMGN (0.16 +/- 0.07 U/10(3) gloms/24 hr) was not significantly elevated compared to normal glomeruli. Glomerular macrophages from rabbits with PAGBMGN produced more IL-1 (3.62 +/- 1.63 U/10(3) cells/24 hr) than blood monocytes (0.51 +/- 0.30 U/10(3) cells/24 hr) or alveolar macrophages (0.24 +/- 0.12 U/10(3) cells/24 hr) from the same animals. These results show that in experimental anti-GBM GN where injury is macrophage dependent, IL-1 production is also macrophage dependent and infiltrating glomerular macrophages are the major source of IL-1. Further, as glomerular IL-1 production was not significantly augmented in GN in the absence of macrophages, glomerular deposition of immunoglobulin and complement alone do not stimulate significant IL-1 production by intrinsic glomerular cells in experimental anti-GBM GN.

Relative contributions of chemo-attractant and terminal components of complement to anti-glomerular basement membrane (GBM) glomerulonephritis

The relative contributions of chemo-attractant and terminal components of complement to heterologous phase glomerular injury was studied in anti-GBM glomerulonephritis in rabbits. Normal rabbits (complement intact) were given anti-GBM antibody at a dose which resulted in 140 micrograms specific kidney-fixed antibody per gram of renal cortex, and developed significant proteinuria (1910 +/- 327 mg/24 h; control 18.2 +/- 6.1 mg/24 h; P less than 0.01). Leucocyte depletion significantly reduced but did not abolish proteinuria (574 +/- 186 mg/24 h, P less than 0.05). Complement depletion of neutrophil-depleted rabbits resulted in a further significant reduction in proteinuria 50.1 +/- 12.2 mg/24 h, P less than 0.05; versus neutrophil-depleted, complement-intact rabbits), indicating that both neutrophil accumulation and complement activation independent of neutrophils contribute to injury in this model. Rabbits congenitally deficient in the sixth component of complement (C6D) developed similar levels of proteinuria (2099 +/- 796 mg/24 h) to normal rabbits given an identical dose of antibody. However, after leucocyte depletion, C6D rabbits developed significantly less proteinuria (135 +/- 56 mg/24 h) than did leucocyte-depleted, complement-intact rabbits (P less than 0.05). These studies show that terminal complement components are not necessary for the full expression of acute anti-GBM antibody-initiated injury in leucocyte-intact rabbits. However, in the absence of leucocytes, C6 and the terminal complement components are apparently responsible for the majority of the complement-dependent glomerular injury.

Macrophage-Fc-receptor affinity: role in cellular mediation of antibody initiated glomerulonephritis

The role of immunoglobulin (Ig) Fc-macrophage cell surface receptor affinity (macrophage Fc-affinity) in determining the mediation systems responsible for immune glomerular injury has been studied. Glomerular injury was initiated in rabbits by the passive administration of immunoglobulin preparations directed against a "planted" glomerular antigen. The mediation systems inducing injury initiated by antibody pools of high and low macrophage Fc-affinity were compared. In this model of glomerulonephritis macrophage Fc-affinity was the only variable. IgFc-macrophage affinity was quantitated in fluid-phase and solid-phase assay systems (high affinity pool KA = 7.05 +/- 1.11 x 10(5) L/M; low affinity pool KA = 0.79 +/- 0.13 x 10(5) L/M). Comparative antibody binding studies demonstrated that renal injury occurred with high affinity antibody at kidney-fixed-antibody (KFA) binding levels significantly below the KFA levels required for glomerular injury with administration of low affinity antibody [KFA's: 25.1 +/- 2.1 micrograms antibody globulin/g kidney cortex (micrograms/g) and 60.5 +/- 2.4 micrograms/g, respectively, P less than 0.01]. Furthermore, antibody with high macrophage Fc-receptor affinity induced a macrophage-mediated, complement-independent glomerular injury while antibody with low macrophage Fc-receptor affinity induced renal injury via complement and neutrophil dependent mechanisms. IgFc-receptor affinity determined the degree of macrophage recruitment into glomeruli via immune adherence mechanisms, and therefore is an important determinant of which inflammatory mediator system is ultimately responsible for antibody-initiated glomerular injury.

Procoagulant activity expression by macrophages from atheromatous vascular plaques

Embolization of thrombi from ulcerated plaques is an important cause of morbidity from atherosclerotic carotid artery disease. Factors controlling thrombus formation on these lesions are not well understood. Macrophages were isolated from atherosclerotic plaques to assess their potential to promote local fibrin deposition. Plaques were collected from 11 patients undergoing carotid endarterectomy and 9 patients undergoing reconstructive procedures for atherosclerotic disease of their distal aorta or femoral arteries. Blood was also collected concurrently to isolate monocytes. Procoagulant activity (PCA) of carotid macrophages (8.6 +/- 4.1 mU/10(6) cells) was significantly higher than that of macrophages from non-carotid lesions (0.35 +/- 0.20 mU/10(6) cells; P less than 0.05) or blood monocytes from either group of patients. The PCA of carotid plaque macrophages from patients with recent emboli was 16.1 +/- 8.4 mU/10(6) cells (n = 5) compared to 2.4 +/- 0.8 mU/10(6) cells (n = 6) for plaque macrophages from assymptomatic carotid endarterectomy patients. Carotid macrophage PCA was factor V and factor VII dependent. Its functional activity was inhibited by an anti-tissue factor antibody, and immunohistochemical studies on tissue sections from carotid plaques showed tissue factor in areas where macrophages were abundant. These studies demonstrate that macrophages within carotid artery plaques have augmented procoagulant activity compared with blood monocytes and macrophages from other atherosclerotic lesions and indicate that carotid plaque macrophages are activated. Augmented macrophage PCA may contribute to thrombus formation on ulcerated plaques.

Localization of antiglomerular basement membrane-binding polyclonal antibodies in rat lung and kidney using post-embedding immunogold electron microscopy

Post-embedding immunogold electron microscopy (IAuEM) techniques utilizing low-temperature embedding in Lowicryl K4m and LR White resin were used to localize the binding sites of two sheep anti-rat glomerular basement membrane polyclonal antibodies (P1 and P2) and a sheep anti-rat lung antigen antibody. P1 localization was bilaminar in a linear pattern along the subepithelial and particularly the subendothelial aspect of the glomerular basement membrane. P2 was bound diffusely throughout the lamina densa, even at supramaximal doses. The anti-lung antibody bound in an interrupted linear pattern throughout the lung basement membrane (alveolar and capillary), and showed an intense, diffuse binding to the glomerular basement membrane. IAuEM allowed definition of the precise basement membrane binding sites of these polyclonal reagents.

Granulocyte independence of pulmonary oxygen toxicity in the rat

The role of neutrophils in the mediation of severe normobaric hyperoxic lung injury has been studied by monitoring the effects of neutrophil depletion on a rat model of pulmonary oxygen toxicity. Pulmonary capillary permeability, assessed using an [125I]albumin lung permeability index (LPI), progressively increased with an increased duration of hyperoxia exposure in normal animals (LPI = 0.43 +/- 0.09 at 24 h; 0.95 +/- 0.17 at 48 h; 1.56 +/- 0.21 at 60 h), despite the absence of any significant tissue or bronchoalveolar lavage evidence of neutrophil infiltration until 60 h of hyperoxia exposure. Neutrophil depletion (using cyclophosphamide) blocked this late neutrophil infiltrate but failed to attenuate lung injury (LPI = 0.38 +/- 0.06 at 24 h; 0.89 +/- 0.16 at 48 h; 1.58 +/- 0.10 at 60 h; all p greater than .05 compared with leucocyte-replete/normal animals exposed to hyperoxia). The temporal dissociation of pulmonary neutrophil accumulation and pulmonary injury and the failure of effective neutrophil depletion to abrogate hyperoxic lung injury indicate that neutrophil polymorphs play no substantive role in the mediation of tissue injury in this model of severe pulmonary oxygen toxicity.

Glomerular macrophages produce reactive oxygen species in experimental glomerulonephritis

The production of reactive oxygen species by intraglomerular macrophages was assessed in a macrophage dependent model of diffuse proliferative glomerulonephritis in rabbits. Glomerular macrophages were obtained from isolated nephritic glomeruli by short term (60 min) culture. Control macrophage populations were simultaneously obtained from peripheral blood (blood monocytes) and lung lavage fluid (alveolar macrophages). Superoxide anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.) production was assessed. Glomerular macrophage production of O2- (48.9 +/- 5.5 nmol/hr/10(6) cells), H2O2 (4.4 +/- 2.5 nmol/hr/10(6) cells) and OH. (57.8 +/- 4.7 U/hr/10(6) cells) was significantly greater than the production of reactive oxygen species seen with control monocyte populations: alveolar macrophages, O2- 9.8 +/- 2.0 nmol/hr/10(6) cells; H2O2 0.6 +/- 0.3 nmol/hr/10(6) cells; OH. 11.0 +/- 1.8 U/hr/10(6) cells; blood monocytes, O2- 8.6 +/- 1.4 nmol/hr/10(6) cells; OH. 9.9 +/- 1.2 U/hr/10(6) cells, (all P less than 0.05 cf. glom macs). Hydrogen peroxide production by blood monocytes (1.6 +/- 0.9 nmol/hr/10(6) cells) was less than glomerular macrophages, however this difference was not statistically significant. The enhanced production of reactive oxygen species by glomerular macrophages in this macrophage dependent model of glomerulonephritis suggests that these mononuclear cells are locally activated within the glomerulus following recruitment from the circulation. Reactive oxygen species production by glomerular macrophages may contribute to their ability to induce glomerular basement membrane injury in this disease.

Glomerular macrophages express augmented procoagulant activity in experimental fibrin-related glomerulonephritis in rabbits

Glomerular fibrin deposition and augmentation of procoagulant activity (PCA) are dependent on glomerular macrophage infiltration in anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM GN) in rabbits. Expression of PCA on the surface of glomerular macrophages and/or augmentation of intrinsic glomerular cell PCA by macrophage cytokines (such as IL 1) are potential mechanisms by which macrophages may augment glomerular PCA. Macrophages were isolated from glomeruli of rabbits developing anti-GBM GN to measure their PCA expression. These macrophages were characterized by morphological and functional criteria. Glomerular macrophages expressed markedly augmented PCA (2.8 +/- 0.7 mU/10(3) cells) compared with blood monocytes (0.05 +/- 0.02 mU/10(3) cells) and alveolar macrophages (0.09 +/- 0.02 mU/10(3) cells) from the same rabbits. Glomerular macrophage PCA was functionally identical to the PCA of whole glomeruli, and was consistent with that of tissue factor. Supernatants from nephritic glomeruli contained IL 1 bioactivity and augmented endothelial cell PCA in vitro. However, these supernatants and purified IL 1 failed to augment the PCA of normal and macrophage-depleted nephritic glomeruli. These studies demonstrate that, in this model of anti-GBM GN, glomerular macrophages contribute directly to the augmented glomerular PCA by their expression of surface membrane PCA, and have the potential to indirectly augment glomerular PCA by their production of cytokines capable of enhancing endothelial cell PCA.

Participation of cell-mediated immunity in deposition of fibrin in glomerulonephritis

Fibrin deposition is prominent in delayed-type hypersensitivity (DTH) reactions and is initiated by antigen-specific, T-lymphocyte-directed macrophage expression of human tissue factor (HTF). To examine the role of DTH in glomerular fibrin deposition, 10 fibrin-positive and 24 fibrin-negative biopsy specimens from patients with glomerulonephritis (GN) and samples from normal controls were studied with monoclonal antibodies against T cells, macrophages, and HTF. Fibrin-positive sections showed intense glomerular staining for HTF and significantly more T cells and macrophages than fibrin-negative specimens. All the essential elements of DTH reactions can therefore be simultaneously demonstrated within glomeruli from patients with fibrin-related GN. These findings suggest a role for cell mediated immunity in GN.

Detection of anti-DNA antibodies: a comparison between two Farr assays, Crithidia luciliae and a human chromosomal substrate assay

Four commercially available assays were compared with a 14C DNA Farr assay for their ability to detect anti-DNA antibodies in 119 sera from 109 patients with systemic lupus erythematosus (SLE) and 25 control sera. The 14C DNA Farr assay was the most sensitive and specific assay (SLE, 57% positive, controls, 0%). A commercial 125I DNA Farr assay was significantly less sensitive (SLE, 39% positive). The fluorescence human chromosomal preparation assay was as sensitive as the 14C DNA Farr assay (SLE, 58% positive) but less specific (controls, 8% positive). The immunofluorescence Crithidia luciliae assay was specific, but less sensitive (SLE, 37% positive) than the 14C DNA Farr assay. Adaptation of Crithidia to immunoperoxidase did not alter its sensitivity or performance. These results confirm that the 14C DNA Farr assay, locally refined and performed by experienced hands, is the most sensitive and specific assay for anti-DNA antibodies. The 125I DNA Farr was no more sensitive than the Crithidia assay but considerably more laborious. The human chromosomal preparation may be suitable as a rapid screening test for anti-DNA antibodies.

A new experimental model of in-situ immune complex disease of the lung

A model of acute immunological lung injury, initiated by the binding of passively administered antibody to an antigen (Concanavalin A (Con A] affixed to the pulmonary endothelium, is described. Pulmonary injury, monitored using the 125I-albumin lung permeability index (LPI) did not occur with antigen deposition alone (LPI 0.235 +/- 0.012). The binding of antibody to the 'planted' lung antigen resulted in injury only when antibody binding exceeded a threshold value of 7.4 +/- 1.4 micrograms antibody globulin per gram of lung. Alevolar-capillary permeability changes were maximal 4 to 8 h after antigen-antibody interaction (LPI at 2 h, 0.353 +/- 0.015: at 4 h, 0.387 +0.33; at 8 h, 0.373 +/- 0.025; at 24 h, 0.289 +/- 0.031; at 48 h, 0.239 +/- 0.022). Lung injury was significantly attenuated by neutrophil (PMN) depletion (LPI at 4 h, 0.325 +/- 0.014: P less than 0.01cf PMN-intact animals), and further reduced by complement depletion (LPI at 4 h, 0.275 +/- 0.023: P less than 0.05 cf PMN-intact and PMN-deplete animals). This model of immune lung injury demonstrates the potential for in situ immune reactions on the pulmonary endothelial surface to induce acute inflammatory injury. Further the model illustrates the cooperative effects of neutrophils and complement in the genesis of inflammation, with both these mediator systems contributing to immunological pulmonary injury.

Alveolar macrophage procoagulant activity is increased in acute hyperoxic lung injury

Alveolar macrophage accumulation and interstitial fibrin deposition are prominent in adult respiratory distress syndrome and chronic interstitial lung diseases. The role of alveolar macrophages in the initiation of fibrin deposition and lung injury in these diseases is uncertain. Expression of procoagulant activity by these cells may provide evidence of macrophage activation and involvement in the initiation of lung fibrin deposition. An experimental model of hyperoxia-induced lung injury in rats was studied for assessment of the relationship of lung injury, fibrin deposition, and alveolar macrophage procoagulant activity. Lung injury was assessed histologically and functionally, and the accumulation of inflammatory cells was quantified by bronchoalveolar lavage. Pulmonary injury, manifested by increased capillary permeability, developed progressively during exposure to hyperoxia and was associated with significant augmentation of the procoagulant activity of alveolar macrophages early in the disease. This increase preceded the accumulation of polymorphonuclear leukocytes. Alveolar macrophage procoagulant activity had functional characteristics consistent with tissue factor. These studies provide evidence of early alveolar macrophage activation in acute hyperoxic lung injury in rats and suggest a role for procoagulant activity in the development of interstitial fibrin deposition.

Isolation and characterization of glomerular macrophages in experimental glomerulonephritis

Adherent cells emigrating from glomeruli of rabbits developing anti-glomerular basement membrane antibody induced glomerulonephritis were isolated and characterized as macrophages. Glomeruli were isolated using a sterile graded sieving technique and cultured in plastic tissue culture flasks. After varying culture times, emigrating adherent cells were harvested by 'cold shock' or trypsin-versene. These cells had the morphological and functional characteristics of macrophages. They were largely mononuclear, esterase-positive, phagocytic cells, which exhibited surface Fc receptors. A mean of 4.8 +/- 2.1 X 10(4) macrophages could be isolated from 2 X 10(4) glomeruli after 1 h in tissue culture. Greater numbers of macrophages could be isolated with further time in culture. After 72 h however, intrinsic glomerular cell contamination occurred. The majority of the cells were viable by fluorescein diacetate hydrolysis, and Trypan Blue exclusion. Further functional studies of these cells may provide some new insights into the cellular basis of macrophage-induced glomerular injury in experimental glomerulonephritis.

Cytomegalovirus infection complicating renal transplantation and its relationship to acute transplant glomerulopathy

The incidence of cytomegalovirus (CMV) infection was established, using laboratory criteria, in 298 patients receiving 362 renal allografts (164/298 = 55%). The incidence of CMV infection did not differ between azathioprine/prednisolone-treated and cyclosporine-treated patients (55% vs. 57% NS). The use of antithymocyte globulin (ATG) increased the incidence of CMV infection (78% vs. 51%: P less than 0.01). Donor and recipient CMV status, known for 116 allografts, did not correlate with the incidence of CMV infection (recipient CMV-positive = 50%; recipient CMV-negative = 54%: NS). CMV infection was responsible for 8 patients' deaths (2.7% mortality). Thirty-three patients with acute transplant glomerulopathy were identified (11%). There was no correlation between acute transplant glomerulopathy and CMV infection. Glomerulopathy was associated with poor graft survival (22/33 patients with a graft survival of less than 6 months). Thus CMV infection, although a common complication of renal transplantation with significant morbidity and mortality, is not closely associated with acute transplant glomerulopathy. Further, the lack of correlation of donor-recipient CMV serologic status with graft outcome limits the usefulness of pretransplantation donor screening.

Nonhepatitis B-associated liver disease in a renal transplant population

The spectrum of liver disease in a population of 293 patients receiving 353 renal transplants (1971-1984) was reviewed. This study looked retrospectively at the histological features of liver disease in this population, and prospectively at the clinical and biochemical features of liver disease associated with renal transplantation. In all patients, infection with hepatitis B was excluded. Six deaths, primarily attributable to hepatic failure have occurred: one, acute herpes simplex infection; one, subacute massive hepatic necrosis of uncertain etiology; two, pretransplant liver disease; and two, posttransplantation cirrhosis of uncertain etiology. Review of the hepatic histology of 26 patients with known liver disease following transplantation revealed a wide range of pathologies with few specific correlations with their clinical status or biochemical tests of liver function. The prevalence of hepatic dysfunction following transplantation in our patient population was assessed by prospective biochemical screening of 111 transplant recipients over a 6-month interval. During this time period, 27 patients (24%) displayed biochemical evidence of hepatic dysfunction. Liver disease was known to have predated transplantation in only three of 27. Episodes of abnormal liver function occasionally occurred during an identifiable acute illness (six of 27), although the majority (21 of 27) had chronic hepatic dysfunction. Transplant recipients with abnormal liver function could not be differentiated from a cohort with normal liver function on the basis of age, sex, duration of graft function, or alcohol/drug intake. The possible etiologies of nonhepatitis B liver dysfunction following renal transplantation are discussed, and the high prevalence of biochemical evidence of hepatic dysfunction in this population free of hepatitis B infection is emphasized.

Glomerular procoagulant activity in human proliferative glomerulonephritis

Mechanisms for initiation of glomerular fibrin deposition were studied using renal tissue obtained from two patients with rapidly progressive, crescentic glomerulonephritis. Histological examination showed extensive glomerular monocyte infiltration and fibrin deposition in both patients. Sonicated cell suspensions of isolated glomeruli from these patients contained markedly augmented levels of procoagulant activity (PCA) compared with the levels found in normal glomeruli. This PCA was characterized as tissue factor by its functional dependence on Factors VII and V, independence of Factors VIII and XII, inhibition by concanavalin A and phospholipase C, and association with cell membranes. Its coagulant activity was also inhibited by a specific monoclonal anti-human tissue factor antibody. Tissue factor could be identified in glomeruli from these two patients by indirect immunofluorescence using this antibody. These studies implicate extrinsic pathway activation via tissue factor in intraglomerular deposition of fibrin in these patients. Activated monocytes, known to be a potent source of procoagulant activity and seen in large numbers within glomeruli from these patients, are a likely source of this tissue factor.

Tubular antigen-associated renal disease in New Zealand white rabbits. II. Investigation of mediators of glomerular injury: localization and characterization of the glomerular capillary wall antigen

Mediation of the glomerular lesion and proteinuria produced by sheep antirabbit F x 1A globulin (SAFG) in rabbits was examined by prior treatment with cobra venom factor and nitrogen mustard. SAFG binding and proteinuria at 24 h were independent of complement or leucocytes but dose dependent. SAFG reacted by immunoblot with a wide range of antigens in deoxycholate extracts of rabbit glomeruli and autologous F x 1A including eight prominent shared bands of 29-128 kd. Immunogold electron microscopy has revealed the in vivo glomerular binding of SAFG as discrete, nonlinear and predominantly within the laminae rarae, in association with epithelial and particularly endothelial components of the glomerular capillary wall. In vitro binding was prominent on the endothelium. Proteinuria in this model is mediated by antibody without requirement for complement or leucocytes. The putative antigen(s) is/are associated with components of the glomerular capillary wall which share epitopes with autologous tubular F x 1A. This model is an example of an in situ immune complex glomerular nephritis and is distinct from the classical anti-F x 1A model, passive Heymann's nephritis in the rat.

Quantitation of intraglomerular mononuclear phagocytes in experimental glomerulonephritis in the rat using specific monoclonal antibodies

Intraglomerular mononuclear phagocytes were quantitated, in normal Sprague-Dawley rats and in animals with diffuse proliferative glomerulonephritis, using recently described specific monoclonal antibodies (ED1, ED2, ED3) and a 4-layer immunoperoxidase technique. Results obtained with the immunoperoxidase technique were compared with estimates of glomerular mononuclear cellularity based upon glomerular histochemistry and glomerular cell culture. Normal animals (n = 12) had no significant glomerular mononuclear phagocyte population by immunoperoxidase [0.01 macrophages per glomerular cross section (MO/gcs)], histochemistry (+0.2 +/- 0.1 staining intensity) or glomerular cell culture [0.10 +/- 0.02 MO/glomerulus (MO/glom)]. Evolution of diffuse proliferative glomerulonephritis was associated with a progressive rise in glomerular mononuclear phagocyte infiltration using all three techniques. Immunoperoxidase staining (ED1) at the time of maximal macrophage infiltration of glomeruli revealed 6.21 +/- 1.78 MO/gcs (n = 12) using the ED1 macrophage marker. This correlated with histochemical (+3.8 +/- 0.2 staining intensity) and glomerular cell culture (17.6 +/- 4.5 MO/glom) estimates of the glomerular mononuclear phagocyte population. In addition, significant numbers of intraglomerular monocytes possessed the ED2 and ED3 macrophage differentiation antigens (0.82 +/- 0.41 and 0.24 +/- 0.15 MO/gcs respectively). Thus these specific monoclonal antibodies provide a reliable and readily reproducible means for the quantitation of intraglomerular mononuclear phagocytes. In addition, they provide evidence for intraglomerular macrophage differentiation in experimental glomerulonephritis in the rat.

Modulation of normobaric pulmonary oxygen toxicity by hydroxyl radical inhibition

The effects of hydroxyl radical inhibition on an experimental model of normobaric pulmonary oxygen toxicity have been studied. The metal ion chelator, desferrioxamine (which inhibits hydroxyl-radical generation) or the hydroxyl-radical scavenger, dimethylthiourea (DMTU), were administered in an attempt to block hydroxyl-radical-mediated tissue injury. Lung injury was monitored in Sprague-Dawley rats by examining lung histology and bronchoalveolar lavage and by assessing pulmonary capillary permeability using the 125I-albumin lung permeability index and the lung weight:body weight ratio. Control animals had lung permeability indices 0.183 +/- 0.005 and lung weight to body weight ratio of 4.50 +/- 0.10 (all as mean +/- SEM). With increased duration of exposure to hyperoxia, there was a progressive increase in pulmonary inflammation, with thickening of alveolar membranes and atelectasis and a progressive increase in lung permeability indices (0.434 +/- 0.088 at 24 hrs; 0.954 +/- 0.165 at 48 hrs; and 1.55 +/- 0.214 at 60 hrs); and lung weight to body weight ratio (5.28 +/- 0.11 at 24 hrs; 6.54 +/- 0.23 at 48 hrs; and 8.91 +/- 0.51 at 60 hrs). Treatment with desferrioxamine provided significant protection from lung injury after 24 hrs of hyperoxia (eg., lung permeability indices 0.250 +/- 0.018; lung weight to body weight ratio 4.68 +/- 0.14, both p less than 0.025; cf. 24-hr hyperoxia controls) but no reduction in pulmonary injury was observed after 48 and 60 hrs of hyperoxia exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of immunofluorescence and immunoperoxidase for demonstration of antinuclear antibodies on HEp-2 substrate

A comparison of antinuclear antibody (ANA) detection on HEp-2 cell substrate, using immunofluorescence (IF) and immunoperoxidase (IP) techniques, was performed on 183 sera from 178 individuals, with and without connective tissue diseases. All sera were number coded and scored blindly by two independent observers. ANA was detected in 61% of sera by IF and 62% of sera by IP. Positive and negative results corresponded between the two techniques in 97% of sera. Patterns and titres corresponded in 85% of positive sera. The two independent observers scored ANA more consistently with IP than with IF. Both methods were technically simple to perform and produced consistent results with control sera. These data show that IP provides results equivalent to the traditional IF technique for demonstrating ANA on HEp-2 substrate. Fewer discordant results between two independent observers using IP suggests that this technique has technical advantages for interpretation of ANA on HEp-2 substrate.

Quantitation and characterization of glomerular procoagulant activity in experimental glomerulonephritis

Glomerular procoagulant activity (PCA) was studied in four different models of experimental glomerulonephritis (GN) in rabbits. These models included 3 macrophage-dependent models: active autologous phase anti-glomerular basement membrane (GBM) antibody induced GN (active anti-GBMGN); passively induced autologous phase anti-GBMGN, and acute serum sickness; and a macrophage independent model of injury, heterologous phase anti-GBMGN was included also. PCA in glomerular lysates was significantly augmented in the three macrophage-dependent models, but not elevated significantly in heterologous anti-GBMGN when compared to glomerular lysates from normal rabbits. The greatest augmentation of PCA was found in glomeruli from rabbits with active anti-GBMGN which also contained the greatest numbers of macrophages. The functional characteristics of the glomerular PCA were similar in each of the models studied. Initiation of coagulation in vitro by these lysates was shown to be dependent on the presence of coagulation Factors VII and V, and largely independent of Factors XII and VIII, suggesting that glomerular PCA activates the extrinsic coagulation pathway. Inhibition studies using concanavalin A and phospholipase C demonstrated that glycoside residues and phospholipids are important chemical moieties for the coagulant activity of PCA. After sonication and ultracentrifugation PCA was found in the cell membrane fraction but not in the cell cytosol of glomerular lysates. These studies provide further evidence that glomerular PCA is markedly augmented in the presence of infiltrating glomerular macrophages and demonstrate that glomerular PCA has the functional characteristics of 'tissue factor', the procoagulant expressed by macrophages on their cell surface membrane. The quantitative association of glomerular PCA with glomerular macrophages, together with the shared functional characteristics of glomerular PCA and macrophage PCA, together suggests that the augmented glomerular PCA in experimental GN is due to tissue factor from infiltrating macrophages (macrophage PCA).

Intrarenal hemodynamic alterations induced by anti-GBM antibody

An isolated perfused kidney system (IPK) was used to study the direct intrarenal hemodynamic effects of binding of anti-glomerular-basement membrane (anti-GBM) antibody in the absence of all other circulating humoral and cellular inflammatory mediators. Control IPK's (perfused with Krebs-Henseleit buffered 5% albumin solution containing non-immune globulin) had a renal vascular resistance (RVR) mean +/- SEM 3.10 +/- 0.47 mm Hg/ml/min and a GFR mean +/- SEM 0.63 +/- 0.8 ml/min/g. Anti-GBM antibody administration raised RVR (4.83 +/- 0.52 mm Hg/ml/min, P less than 0.01) and lowered GFR (0.34 +/- 0.04 ml/min/g, P less than 0.01). Perfusate renin activity was higher after antibody administration (684 +/- 87 ng AI/ml/hr compared with control 308 +/- 42 ngAI/ml/hr, P less than 0.01). Treatment with Sar1Ala8All (3 X 10(-6) M) or captopril (10 mg/ml) attenuated antibody-induced vasoconstriction (RVR mm Hg/ml/min, Sara1Ala8All = 3.78 +/- 0.13 captopril = 3.26 +/- 0.12, both P less than 0.05 compared with anti-GBM alone). Both inhibitors of the renin-angiotensin system (RAS) also aggrevated the decline in GFR seen after antibody administration (GFR ml/min/g, Sara1Ala8All = 0.24 +/- 0.05, Captopril = 0.18 +/- 0.03, both P less than 0.05 compared with anti-GBM alone). These IPK studies demonstrate that anti-GBM antibody itself may directly induce intrarenal hemodynamic alterations in the absence of complement activation, neutrophil infiltration, neural influences or circulating vasoactive substances. The results from perfusate renin sampling and blockade of the RAS provide evidence that anti-GBM antibody deposition activates the intrarenal RAS and thereby induces significant hemodynamic alterations.

Hydroxyl radical mediation of immune renal injury by desferrioxamine

The acute phase of glomerular injury in a model of antiglomerular basement membrane, antibody-induced glomerulonephritis (antiGBM-GN) in rabbits was shown to be neutrophil-dependent using nitrogen mustard depletion studies. Administration of desferrioxamine (DFX) prevented the development of proteinuria in this model of renal injury [24 hr protein excretion (mean +/- SEM): antiGBM-GN/DFX = 16.2 +/- 2.9 mg compared with antiGBM-GN control = 271.5 +/- 92.2 mg, P less than 0.01]. Antibody binding levels, glomerular filtration rates, circulating complement and neutrophil counts, glomerular C3 deposition, and neutrophil infiltration did not differ between DFX treated and antiGBM-GN groups. In vitro assay systems to assess oxygen radical production [superoxide anion (O2-) and hydroxyl radical (OH.)] by neutrophils activated via the interaction of antiGBM antibody, GBM and complement were established. In these assays, DFX inhibited OH. production by immunologically-stimulated neutrophils (ISN) [nM diphenol/hr/10(6) cells, mean +/- SEM, ISN/DFX = 8 +/- 2 compared with ISN = 191 +/- 22, P less than 0.01] while production of O2- was not affected [nM O2-/hr/10(6) cells, mean +/- SEM, ISN/DFX = 29.1 +/- 4.3 compared with ISN = 32.6 +/- 2.5, P greater than 0.05]. These studies demonstrate that the iron chelator desferrioxamine can prevent neutrophil-dependent immune renal injury by interfering with neutrophil function. Treatment with the hydroxyl radical scavenger dimethylthiourea also significantly attenuated renal injury in antiGBM-GN. Together, the in vivo and in vitro data strongly suggest that neutrophil-dependent immunological renal injury is mediated via hydroxyl radical production by activated neutrophils within glomeruli.

Direct antiGBM antibody induced alterations in glomerular permselectivity

The glomerular fixation of anti-glomerular-basement-membrane (antiGBM) antibody is associated with complement activation, neutrophil accumulation, and renal injury. This injury manifests both as an increase in the rate of urinary protein excretion and altered renal hemodynamic characteristics. We have utilized an isolated perfused kidney system (IPK) to assess the capacity of antiGBM antibody to alter glomerular permselectivity in the absence of both glomerular complement activation and neutrophil infiltration. Control perfusions with Krebs-Henseleit buffered 5% albumin solutions containing normal sheep globulin had a protein excretion rate of 0.223 +/- 0.044 mg/min (mean +/- SEM). Assessment of glomerular permselectivity using fractional dextran clearances demonstrated an intact negative charge barrier in control preparations. AntiGBM antibody bound in a dose related fashion to the kidney and was localized to the glomerular basement membrane on immunofluorescence. Antibody induced a significant increase in mean protein excretion (2.009 +/- 0.681 mg/min, P less than 0.01) in association with a loss of the glomerular filter's negative charge barrier. These IPK studies demonstrate that antiGBM antibody can itself produce proteinuria, in association with loss of the glomerular capillary negative charge barrier, in the absence of all circulating humoral and cellular inflammatory mediator systems.