Immune reactivity and immunosuppressive intervention (TLI) in experimental nephritis. I. Immunopathologic correlates in the accelerated autologous form of nephrotoxic serum nephritis

The progression of histologic changes observed in the accelerated autologous form of nephrotoxic serum nephritis (AA-NTSN) in the inbred LEW rat, ranging from minimal endocapillary proliferation to marked endo- and extra-capillary proliferation together with fibrin deposition and necrosis of glomerular tufts, was closely correlated (day 8) with parallel measures of albuminuria (1.6 leads to 280 mg/24 hr). In the induction phase of AA-NTSN (day 0) a direct linear correlation (r = 0.72, p less than 0.05) was obtained between anti-SGG antibody levels and 24-hr urine albumin excretion. Subsequent observations (day 7) yield an inverse correlation between anti-SGG antibody and albuminuria (r = -0.54, p less than 0.01), and this change was shown to be related to the loss of specific antibody in the urine (r = 0.59, p less than 0.025). Although splenic T cells of rats with AA-NTSN manifest a specific proliferative response to the inducing antigen SGG, and although the magnitude of this proliferative response (day 7) correlates directly with parallel measures of urine albumin excretion (r = 0.71, p less than 0.02), delayed-type hypersensitivity (DTH) to SGG measured by radiometric ear assay was inversely correlated with albuminuria in this model of experimental nephritis (r = 0.80, p less than 0.01). Additional data are presented that strongly suggest that persistent albuminuria at 1 mo after induction of AA-NTSN is independent of ongoing immunopathologic processes. Thus, glomerular injury in AA-NTSN, previously linked to prominent glomerular macrophage accumulation, is shown to be primarily dependent on a brisk antibody response to the planted heterologous (sheep) immunoglobulin, whereas cellular immunity, readily demonstrated in the splenic T cell compartment, is likely to be of lesser import in the pathogenesis of this lesion in the intact animal.     

Complement alternative pathway activation in the autologous phase of nephrotoxic serum nephritis

The complement cascade is an important part of the innate immune system, but pathological activation of this system causes tissue injury in several autoimmune and inflammatory diseases, including immune complex glomerulonephritis. We examined whether mice with targeted deletion of the gene for factor B (fB(-/-) mice) and selective deficiency in the alternative pathway of complement are protected from injury in the nephrotoxic serum (NTS) nephritis model of antibody-mediated glomerulonephritis. When the acute affects of the anti-glomerular basement membrane antibody were assessed, fB(-/-) mice developed a degree of injury similar to wild-type controls. If the mice were presensitized with sheep IgG or if the mice were followed for 5 mo postinjection, however, the fB(-/-) mice developed milder injury than wild-type mice. The immune response of fB(-/-) mice exposed to sheep IgG was similar to that of wild-type mice, but the fB(-/-) mice had less glomerular C3 deposition and lower levels of albuminuria. These results demonstrate that fB(-/-) mice are not significantly protected from acute heterologous injury in NTS nephritis but are protected from autologous injury in response to a planted glomerular antigen. Thus, although the glomerulus is resistant to antibody-initiated, alternative pathway-mediated injury, inhibition of this complement pathway may be beneficial in chronic immune complex-mediated diseases.     

Increased susceptibility of decay-accelerating factor deficient mice to anti-glomerular basement membrane glomerulonephritis

To prevent complement-mediated autologous tissue damage, host cells express a number of membrane-bound complement inhibitors. Decay-accelerating factor (DAF, CD55) is a GPI-linked membrane complement regulator that is widely expressed in mammalian tissues including the kidney. DAF inhibits the C3 convertase of both the classical and alternative pathways. Although DAF deficiency contributes to the human hematological syndrome paroxysmal nocturnal hemoglobinuria, the relevance of DAF in autoimmune tissue damage such as immune glomerulonephritis remains to be determined. In this study, we have investigated the susceptibility of knockout mice that are deficient in GPI-anchored DAF to nephrotoxic serum nephritis. Injection of a subnephritogenic dose of rabbit anti-mouse glomerular basement membrane serum induced glomerular disease in DAF knockout mice but not in wild-type controls. When examined at 8 days after anti-glomerular basement membrane treatment, DAF knockout mice had a much higher percentage of diseased glomeruli than wild-type mice (68.8 +/- 25.0 vs 10.0 +/- 3.5%; p < 0.01). Morphologically, DAF knockout mice displayed increased glomerular volume (516 +/- 68 vs 325 +/- 18 x 10(3) microm(3) per glomerulus; p < 0.0001) and cellularity (47.1 +/- 8.9 vs 32.0 +/- 3.1 cells per glomerulus; p < 0.01). Although the blood urea nitrogen level showed no difference between the two groups, proteinuria was observed in the knockout mice but not in the wild-type mice (1.4 +/- 0.7 vs 0.02 +/- 0.01 mg/24 h albumin excretion). The morphological and functional abnormalities in the knockout mouse kidney were associated with evidence of increased complement activation in the glomeruli. These results support the conclusion that membrane C3 convertase inhibitors like DAF play a protective role in complement-mediated immune glomerular damage in vivo.     

Evidence for direct renal injury as a consequence of glomerular complement activation

An isolated perfused kidney (IPK) preparation was used to study the functional consequences of antibody-initiated glomerular complement activation in an environment devoid of circulating inflammatory cells. Control IPK, with antibody bound to the glomerular basement membrane (GBM) (mean +/- SEM, 165.0 +/- 5.7 micrograms globulin/g renal cortex), were perfused with a 5% albumin solution. Control urinary protein excretion was 0.306 +/- 0.112 mg/min, renal vascular resistance (RVR) was 4.72 +/- 0.69 mgHg/ml/min, and the glomerular filtration rate (GFR) was 0.41 +/- 0.01 ml/min/g. To produce glomerular complement activation, IPK with equal quantities of bound antibody (167.0 +/- 6.1 micrograms/g) were perfused with fresh plasma. Glomerular complement activation was associated with linear deposition of C3 on the GBM, a significant increase in protein excretion (3.317 +/- 1.077 mg/min; p less than 0.001) and RVR (10.15 +/- 1.85 mmHg/ml/min; p less than 0.001), and a decline in GFR (0.38 +/- 0.01 ml/min/g; p less than 0.05). Equivalent IPK perfused with decomplemented plasma demonstrated neither glomerular complement deposition nor augmented renal injury. By using both complement repletion and depletion techniques, this study demonstrates that antibody-initiated glomerular complement activation produces direct, neutrophil-independent renal injury. Thus, activated complement components may directly contribute to antibody-induced immune renal injury, in addition to their well established role in the recruitment of circulating inflammatory cells.     

Anti-DNA antibodies bind directly to renal antigens and induce kidney dysfunction in the isolated perfused rat kidney

The pathogenesis of SLE is commonly attributed to the deposition of circulating immune complexes consisting of DNA and anti-DNA autoantibodies. However, recent work has shown multiple cross-reactions between anti-DNA antibodies and a variety of cellular and extracellular Ag. To test the possibility that these antibodies interact directly with glomerular Ag and induce kidney dysfunction, we applied mouse and human anti-DNA IgG to the isolated perfused rat kidney. The NZB/NZW mouse monoclonal anti-DNA bound to glomerular Ag with a concomitant induction of proteinuria and a decrease in inulin clearance. The albumin excretion was 2301 +/- 734 micrograms/min at 160 min of perfusion, as compared with 85 +/- 21 micrograms/min in controls (p less than 0.001). The inulin clearance was reduced to 0.17 +/- 0.02 ml/min as compared with 0.28 +/- 0.09 ml/min in controls (p less than 0.05). Polyclonal anti-DNA IgG obtained from patients with lupus nephritis bound to rat glomeruli and induced albumin excretion of 542 +/- 217 micrograms/min at 160 min of perfusion, as compared with 163 +/- 77 micrograms/min in controls (p = NS). The addition of plasma as a source of C to the human IgG increased the proteinuria markedly (albumin excretion of 1115 +/- 195 micrograms/min at 160 min of perfusion, p less than 0.02), probably due to C activation. Preincubation of the reactive mouse and human IgG with DNA completely abolished their binding to renal tissue and its physiologic consequences. These results suggest that direct binding of anti-DNA antibodies to renal Ag may play an important role in the induction of lupus nephritis.     

Control of autologous immune complex nephritis. I. Suppression of the disease in the presence of T cell sensitization

Pretreatment of Lewis and Sprague-Dawley rats with the nephritogenic antigen, Fx1A, in incomplete Freund's adjuvant (IFA) reduced the incidence of autologous immune complex nephritis in rats subsequently challenged with Fx1A in complete Freund's adjuvant (CFA). The suppression was evidenced by a decrease in antibody production, in glomerular deposition of immunoglobulins, and in the incidence of proteinuria, and it was antigen specific. In vitro blastogenesis to Fx1A of lymphocytes from Fx1A-IFA-pretreated animals was normal. Rats pretreated with Fx1A-IFA initially developed a normal antibody response after challenge with Fx1A-CFA, but the response was not sustained. These results indicate that the Fx1A-IFA-induced suppressor mechanism does not inhibit sensitization, but rather modifies specific antibody production.     

Polyreactive autoantibodies are nephritogenic in murine lupus nephritis

To characterize the antibodies that form glomerular immune deposits in lupus nephritis, immunoglobulin (Ig) was eluted from the perfused kidney cortices of female MLR-lpr/lpr mice with early nephritis. The eluted Ig was predominantly IgG with antibody activity against DNA, multiple polynucleotides, SmRNP, gp70, and levan that was greater than the serum antibody activity of age- and sex-matched mice. Of particular interest, both kidney eluate and serum anti-DNA antibodies were observed to cross-react with multiple polynucleotides; however, only the kidney eluate Ig cross-reacted with phospholipids and RNA. Furthermore, the anti-DNA antibodies in the kidney eluate also cross-reacted with SmRNP and gp70; these ligand-binding properties were shared by the Ig in the kidney eluate that did not bind to DNA; and both kidney eluate fractions shared Id-H130 activity (a high frequency MRL-1pr/1pr idiotype). In contrast, the spectrotypes of Ig in the kidney eluate were found to be similar to serum, and they were observed to be between isoelectric points 6.5 to 7.8. Both the anti-DNA antibodies and the Ig that did not bind to DNA had similar isoelectric points throughout this entire range. These findings indicate that polyreactivity is a distinguishing feature of nephritogenic autoantibodies. They also raise the possibility that these ligand-binding properties influence the capacity of autoantibodies to form immune deposits. This influence could occur because polyreactive antibodies cross-react with antigenic determinants within the normal glomerular capillary wall. Alternatively, polyreactive antibodies may more readily form circulating immune complexes that are, in turn, passively trapped within the glomerulus.     

Protection of kidney function and decrease in albuminuria by captopril in insulin dependent diabetics with nephropathy.

STUDY OBJECTIVE--To assess whether long term inhibition of angiotensin converting enzyme with captopril and frusemide or bendrofluazide protects kidney function in diabetic nephropathy. DESIGN--Non-randomised controlled before-after trial of matched hypertensive insulin dependent diabetics with nephropathy treated with captopril and frusemide or bendrofluazide. SETTING--Outpatient diabetic clinic in tertiary referral centre. PATIENTS--Treatment group of 18 hypertensive insulin dependent diabetics with nephropathy (mean age 33), who had not been treated previously. Control group of 13 patients (mean age 32) fulfilling the same entry criteria from a prospective study. INTERVENTIONS--Treatment group was given daily captopril 37.5-100.0 mg and frusemide (mean) 98 mg (10 patients) or bendrofluazide (mean) 4 mg (seven). Treatment was continued for about two and a half years. Controls were not treated. END POINT--Measurement of arterial blood pressure, albuminuria, and glomerular filtration. MEASUREMENTS AND MAIN RESULTS--Baseline values were identical in treated and untreated groups respectively: mean blood pressure 146/93 (SE 3/1) mm Hg v 137/95 (2/1) mm Hg; geometric mean albuminuria 982 (antilog SE 1.2) micrograms/min v 936 (1.2) micrograms/min; and mean glomerular filtration rate 98 (SE 5) ml/min/1.73 m2 v 96 (6) ml/min/1.73 m2. Mean arterial blood pressure fell by 8.7 (1.3) mm Hg with captopril and rose by 6.6 (1.5) mm Hg in controls, (p less than 0.001); Albumin excretion decreased to 390 (1.1) micrograms/min with captopril and rose to 1367 (1.3) micrograms/min in controls (p less than 0.001). The rate of decrease in glomerular filtration rate was lower with captopril (5.8 (0.7) ml/year v 10.0 (1.3) ml/year) (p less than 0.01). Rate of fall in glomerular filtration rate and mean arterial blood pressure were significantly correlated (n = 31, r = 0.37, p less than 0.05). CONCLUSIONS--Captopril is a valuable new drug for treating hypertension in insulin dependent diabetics with nephropathy.     

Effect of captopril on kidney function in insulin-dependent diabetic patients with nephropathy.

The influence of angiotensin II on kidney function in diabetic nephropathy was assessed by studying the effect of 12 weeks'' monotherapy with captopril (25-50 mg twice a day) in 16 hypertensive insulin dependent diabetic patients with persistent albuminuria. In an initial one week randomised single blind trial of captopril versus placebo, captopril (for nine patients) reduced arterial blood pressure from 148/94 (SD11/6) to 135/88 (8/7) mm Hg (p less than 0.05) and albuminuria from 1549 (range 352-2238) to 1170 (297-2198) micrograms/min (p less than 0.05), while glomerular filtration rate remained stable. No significant changes occurred in seven patients treated with placebo. During the 12 weeks of captopril treatment arterial blood pressure in all patients fell from 147/94 (11/6) to 135/86 (13/7) mm Hg (p less than 0.01), albuminuria fell from 1589 (range 168-2588) to 1075 (35-2647) micrograms/min (p less than 0.01), and glomerular filtration rate fell from 99 (SD19) to 93 (25) ml/min/1.73 m2 (p less than 0.01). The renin-angiotensin system showed suppressed plasma concentrations of angiotensin II and increased concentrations of angiotensin I and renin. The study showed that glomerular filtration rate is not dependent on angiotensin II, that captopril reduces albuminuria, probably by lowering glomerular hypertension, and that captopril represents a valuable new drug for treating hypertension in diabetics dependent on insulin with nephropathy.     

Autologous immune complex nephritis associated with sickle cell trait: diagnosis of the haemoglobinopathy after renal structural and immunological studies.

A renal tubular epithelial antigen (RTE)--anti-RTE autologous immune complex nephritis associated with sickle cell anaemia (SS) has been reported, but immune complex nephritis has never been described in patients with sickle cell trait (SA). During investigation of a child with "asymptomatic proteinuria" cryoprecipitable complexes of RTE-anti-RTE were detected in the serum and granular deposits of RTE, immunoglobulins, and complement localised on the glomerular basement membranes. Morphological and ultrastructural studies showed increased mesangial matrix, sickled red blood cells in the glomeruli and vessels, and tubular and interstitial abnormalities. These findings prompted haemoglobin electrophoretic studies, which showed previously undiagnosed haemoglobin SA in this patient and her family. These observations suggest that nephritis mediated by similar immunopathogenic mechanisms may be associated with SS and SA haemoglobinopathy. Under some conditions patients with sickle cell trait may experience haemodynamic and oxygenation abnormalities, which may be aetiological factors in the immune complex nephritis associated with SS disease.     

Phorbol myristate acetate-induced injury of isolated perfused rat lungs: neutrophil dependence

The effect of leukocyte depletion on acute lung injury produced by intravenous or intratracheal phorbol myristate acetate (PMA) administration was studied in isolated perfused rat lungs. Vascular endothelial permeability was assessed by use of the capillary filtration coefficient (Kf,c). A predicted pulmonary capillary pressure (Ppc,p) was calculated from measurements of postcapillary resistances. These parameters were measured before and 90 min after the administration of PMA, either intratracheally or intravascularly. When blood elements were present both intratracheal and intravascular PMA caused an increased Kf,c [0.27 +/- 0.02 vs. 0.99 +/- 0.22 and 0.25 +/- 0.05 vs. 0.64 +/- 0.15 (SE) ml.min-1.cmH2O-1.100 g-1, respectively; P less than 0.05] and an increased Ppc,p (8.3 +/- 0.4 vs. 74.7 +/- 18.3 and 8.7 +/- 0.8 vs. 74.2 +/- 25.1 cmH2O, respectively; P less than 0.05). Removal of circulating leukocytes abolished the increased Kf,c when PMA was given intratracheally (0.35 +/- 0.06 vs. 0.23 +/- 0.07 ml.min-1.cmH2O-1.100 g-1) or intravascularly (0.39 +/- 0.07 vs. 0.33 +/- 0.07 ml.min-1.cmH2O-1.100 g-1). In the absence of neutrophils, Ppc,p slightly increased with intratracheal PMA, from 6.9 +/- 0.5 to 10.5 +/- 1.1 cmH2O (P less than 0.05), but was unchanged at 90 min with intravascular PMA. Depletion of circulating neutrophils with an antineutrophil serum failed to block the Kf,c change with intratracheal PMA (from 0.24 +/- 0.03 to 0.42 +/- 0.09 ml.min-1.cmH2O-1.100 g-1; P less than 0.05). Ppc,p also increased from 6.9 +/- 0.6 to 19.8 +/- 6.7 cmH2O (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Early adaptations in blood substrates, metabolites, and hormones to prolonged exercise training in man.

This study was designed to investigate the effect of short-term, submaximal training on changes in blood substrates, metabolites, and hormonal concentrations during prolonged exercise at the same power output. Cycle training was performed daily by eight male subjects (VO2max = 53.0 +/- 2.0 mL.kg-1.min-1, mean +/- SE) for 10-12 days with each exercise session lasting for 2 h at an average intensity of 59% of VO2max. This training protocol resulted in reductions (p less than 0.05) in blood lactate concentration (mM) at 15 min (2.96 +/- 0.46 vs. 1.73 +/- 0.23), 30 min (2.92 +/- 0.46 vs. 1.70 +/- 0.22), 60 min (2.96 +/- 0.53 vs. 1.72 +/- 0.29), and 90 min (2.58 +/- 1.3 vs. 1.62 +/- 0.23) of exercise. The reduction in blood lactate was also accompanied by lower (p less than 0.05) concentrations of both ammonia and uric acid. Similarly, following training lower concentrations (p less than 0.05) were observed for blood beta-hydroxybutyrate (60 and 90 min) and serum free fatty acids (90 min). Blood glucose (15 and 30 min) and blood glycerol (30 and 60 min) were higher (p less than 0.05) following training, whereas blood alanine and pyruvate were unaffected. For the hormones insulin, glucagon, epinephrine, and norepinephrine, only epinephrine and norepinephrine were altered with training. For both of the catecholamines, the exercise-induced increase was blunted (p less than 0.05) at both 60 and 90 min. As indicated by the changes in blood lactate, ammonia, and uric acid, a depression in glycolysis and IMP formation is suggested as an early adaptive response to prolonged submaximal exercise training.     

Alterations in Fc receptor function of macrophages from streptozotocin-induced diabetic rats

The presence of elevated levels of circulating immune complexes in diabetic humans and animals suggests impaired phagocyte function. To evaluate FcR-mediated phagocytosis, resident peritoneal macrophages were harvested from control, streptozotocin-induced diabetic, and insulin-treated diabetic rats. FcR number and avidity were determined from Scatchard analysis of binding of 125I-labeled aggregated rat IgG (ARG) to macrophages. The total and fractional catabolic capacity were determined by quantitating the digestion of ARG as a percent of the total ARG added and as a percent of ARG bound. Insulin-deficient diabetic rats had an increase in the number of FcR per cell (26.8 +/- 3.5 X 10(4)) as compared with control animals (13.1 +/- 1.2 X 10(4)) (p less than 0.01). In contrast, insulin-treated diabetic animals had a reduction in the number of FcR per cell (9.8 +/- 1.4 X 10(4)) (p less than 0.01). FcR of macrophages from insulin-deficient diabetic rats had a lower avidity (Kd = 6.9 +/- 1.8 X 10(-10)M) when compared with control (3.7 +/- 0.6 X 10(-10)M) and insulin-treated diabetic rats (3.6 +/- 0.9 X 10(-10)M) (p less than 0.01). Total catabolism of ARG by macrophages from both insulin-deficient and insulin-treated diabetic rats was reduced (31.0% +/- 3.4 and 17.5% +/- 3, respectively) when compared with controls (49.6% +/- 5.2) (p less than 0.01). Fractional catabolism by macrophages from insulin-deficient diabetic rats was significantly reduced (21% +/- 1.9 and 4.6% +/- 0.9/10(4) FcR) when compared with results from control rats (26% +/- 1.3 and 6.7% +/- 0.7/10(4) FcR) (p less than 0.01), whereas the results from insulin-treated diabetic rats (32% +/- 2.4 and 10.8% +/- 1.0/10(4) FcR) (p less than 0.01) were greater than those from controls. These studies demonstrate that FcR-mediated phagocytosis of soluble, "model" immune complexes is impaired in macrophages from both insulin-deficient and insulin-treated diabetic rats; however, different mechanisms account for this impairment in phagocytosis. Despite an increase in FcR number of macrophages from insulin-deficient diabetic rats, the depression of post-receptor-mediated catabolism results in a net depression in phagocytic activity. In contrast, macrophages from insulin-treated diabetic rats display augmented post-receptor-mediated catabolism; however, this does not overcome the low initial binding of ARG to the cell that results from the depression of FcR number.     

Glomerular eicosanoid production in acute serum sickness nephritis

To determine if the induction of immune-mediated glomerular injury influences the formation of glomerular cyclooxygenase products, we measured thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and prostaglandin E2 (PGE2) production by isolated glomeruli of rabbits induced with acute serum sickness nephritis by the administration of bovine serum ablumin (BSA). Animals were randomly assigned to one of three experimental groups: animals injected with BSA (BSA group; n = 11); animals injected with normal saline (control group; n = 11); and animals injected with BSA which were treated with the thromboxane synthetase inhibitor, OKY-046 (BSA + OKY-046; n = 6). Animals in the BSA and BSA + OKY groups developed severe proteinuria and glomerular histologic lesions of nephritis. No differences in proteinuria, serum creatinine and severity of histologic nephritis were observed between the two groups. Examination of glomerular eicosanoid production at the end of the experiment showed a marked reduction of glomerular PGE2 and 6-keto-PGF1 alpha production with a smaller reduction of glomerular TXB2 production in the BSA group. In the BSA + OKY-046 group, the production of TXB2 was significantly less than that in the BSA group; despite this, no effect on proteinuria could be discerned.     

Respective roles of decay-accelerating factor and CD59 in circumventing glomerular injury in acute nephrotoxic serum nephritis

Decay-accelerating factor (DAF or CD55) and CD59 are regulators that protect self cells from C3b deposition and C5b-9 assembly on their surfaces. Their relative roles in protecting glomeruli in immune-mediated renal diseases in vivo are unknown. We induced nephrotoxic serum (NTS) nephritis in Daf1(-/-), CD59a(-/-), Daf1(-/-)CD59a(-/-), and wild-type (WT) mice by administering NTS IgG. After 18 h, we assessed proteinuria, and performed histological, immunohistochemical, and electron microscopic analyses of kidneys. Twenty-four mice in each group were studied. Baseline albuminuria in the Daf1(-/-), CD59a(-/-), and Daf1(-/-)CD59a(-/-) mice was 82, 83, and 139 as compared with 92 microg/mg creatinine in the WT controls (p > 0.1). After NTS, albuminuria in CD59a(-/-) and WT mice (186 +/- 154 and 183 +/- 137 microg/mg creatinine, p > 0.1) was similar. In contrast, Daf1(-/-) mice developed severe albuminuria (378 +/- 520, p < 0.05) that was further exacerbated in Daf1(-/-)CD59a(-/-) mice (577 +/- 785 micro g/mg creatinine, p < 0.05). Glomerular histology showed essentially no infiltrating leukocytes in any group. In contrast, electron microscopy revealed prominent podocyte foot process effacement in Daf1(-/-) mice with more widespread and severe damage in the double knockouts compared with only mild focal changes in CD59a(-/-) or WT mice. In all animals, deposition of administered (sheep) NTS Ig was equivalent. This contrasted with marked deposition of both C3 and C9 in Daf1(-/-)CD59a(-/-) and Daf1(-/-) mice, which was evident as early as 2 h post-NTS injection. The results support the proposition that in autoantibody-mediated nephritis, DAF serves as the primary barrier to classical pathway-mediated injury, while CD59 limits consequent C5b-9-mediated cell damage.     

Endothelial expression of VCAM-1 in experimental crescentic nephritis and effect of antibodies to very late antigen-4 or VCAM-1 on glomerular injury

The migration of leukocytes into glomeruli in crescentic glomerulonephritis is fundamental to pathogenesis, and offers important therapeutic opportunities. We addressed the importance of VCAM-1, and its leukocyte ligand very late antigen-4 (VLA-4), in such leukocyte migration. In a rat model of nephrotoxic nephritis, glomerular expression of VCAM-1, studied by immunohistochemistry, was up-regulated by day 6 of nephritis. To quantify kidney endothelial VCAM-1 expression, a differential radiolabeled mAb technique was used, which demonstrated that protein expression was not up-regulated by day 2 of nephritis, but rose threefold between days 2 and 5, and remained elevated until at least day 28. An in vivo study was then performed, using blocking mAbs to either VCAM-1 or VLA-4, starting mAb treatment on the day prior to disease induction, and continuing until animals were sacrificed at day 7. mAbs to VLA-4 significantly attenuated renal injury (albuminuria, glomerular fibrinoid necrosis, and crescent formation), but mAbs to VCAM-1 had no significant effect. Surprisingly, the number of leukocytes within glomeruli was unaffected by anti-VLA-4 mAb therapy, despite the reduction in renal injury. Paradoxically, classical markers of macrophage activation were increased in the anti-VLA-4- and anti-VCAM-1-treated animals. This study demonstrates that kidney endothelial VCAM-1, in contrast to ICAM-1, is not up-regulated by day 2 of nephrotoxic nephritis, and plays little part in early leukocyte influx into glomeruli. However, VLA-4 is an important mediator of glomerular injury, operating after transendothelial leukocyte migration, and presumably binding to alternate ligands within the kidney.     

Effect of steroids and antisteroids on human meningioma cells in primary culture

Human meningiomas are rich in progestin receptors but virtually devoid of oestrogen receptors. We have studied the hormonal sensitivity of meningioma cells in vitro during 8 days of primary culture in the presence of different steroids and antisteroids. On day 8 the thymidine labelling index (TLI) was determined as a measure of cell growth. To date 30 cultures have been established from 39 tissue specimens. 13 cultures had a TLI below 1.0 and their growth were not affected by hormones. The TLI of the other 17 cultures was 3.0 +/- 1.7 (mean +/- SD; range 1.2-7.7). Following culture in the presence of 1 and 10 nM progesterone TLI was 83 +/- 28% (n = 9) and 61 +/- 29% (n = 3) of that of the control cultures respectively. Although in individual cultures occasional differences were found, the overall values are not statistically different from 100. Similarly, 1 nM of oestradiol and testosterone had no effect on the TLI (n = 3). Tamoxifen at 1 nM increased the TLI to 138% in one culture and decreased it to 66% of the control in another. The antiprogestin mifepristone (RU 486) in concentrations of 0.1, 1.0, 10, 100 and 1000 nM decreased the TLI to 72 +/- 30; 54 +/- 20; 55 +/- 20; 59 +/- 18 and 65 +/- 10 respectively (n = 6-15; P less than 0.05 vs control). It is concluded that although a growth promoting effect of progestins on meningioma could not be shown, the therapeutic possibilities of antiprogestins warrant further investigation.     

Use of total lymphoid irradiation (TLI) in studies of the T cell-dependence of autoantibody production in rheumatoid arthritis

The effect of total lymphoid irradiation (TLI) on T cell-dependent and -independent humoral immune responses was studied in patients with intractable rheumatoid arthritis (RA). The serum levels of several autoantibodies and of antibodies to diphtheria (DT) and tetanus (TT) toxoids and to pneumococcal polysaccharide (PPS; 12 antigenic types) were studied before and after TLI. In addition, the patients were given a booster injection of DT and TT and a single injection of pneumococcal vaccine after radiotherapy. Antibody levels to DT and TT decreased about twofold after TLI and did not rise significantly (p greater than 0.05) after a booster injection. However, there was no reduction in antibody levels to PPS after TLI, and a significant rise in titers was observed after a single vaccination (p less than 0.01). The serum levels of rheumatoid factor (RF), anti-nuclear antibody (ANA), and granulocyte associated IgG rose slightly after TLI. Thus, the autoantibodies and antibodies to polysaccharides appear to be relatively independent of helper T cell function, which is markedly reduced after TLI. On the other hand, antibodies to protein antigens such as DT and TT appear to be more closely dependent upon T helper function in man, as has been reported in rodents. The findings suggest that T cell-independent autoantibody responses alone do not maintain the joint disease activity in RA, because improvement in joint disease after TLI has been reported.     

Proximal and distal tubular activity in chronically catheterized fetal sheep compared with the adult

Renal function was studied in unanaesthetized fetal sheep aged 112-120 and 126-132 days and in adult nonpregnant ewes. The clearance of lithium was used to measure proximal and distal fractional sodium reabsorption. In five nonpregnant adult sheep, 80.6 +/- 1.7% (SE) of the filtered sodium load was reabsorbed proximally and 18.2 +/- 1.53% distally. This was different from all groups of fetal sheep (p less than 0.001). In younger fetuses, proximal fractional sodium reabsorption was less (51.3 +/- 2.3% (SE), p less than 0.05) and distal fractional sodium reabsorption greater (42.4 +/- 2.3% (SE), p less than 0.05) than older fetuses (126-132 days old) in which 61.4 +/- 2.4% (SE) was reabsorbed proximally and 33.6 +/- 2.5% (SE) distally. In another group of fetuses aged 125-137 days, in which proximal tubular sodium reabsorption was measured after distal tubular blockade, proximal fractional sodium reabsorption was 57.8 +/- 2.95% (SE) and distal fractional sodium reabsorption, 38.7 +/- 2.64% (SE). In adult sheep there was no relationship between distal tubular sodium reabsorption and glomerular filtration rate, i.e., proximal tubular function was responsible for glomerulotubular balance. However, in the fetuses, both proximal and distal tubular sodium reabsorption contributed to glomerulotubular balance. Thus in fetal life, the proximal tubule participates to a lesser extent in reabsorbing the filtered sodium load possibly because its function is suppressed by its relatively "volume-expanded" state or because it is functionally immature. Therefore, a greater proportion is reabsorbed distally and the distal nephron participates under physiological conditions in glomerulotubular balance.