Th1 and Th2 T helper cell subsets affect patterns of injury and outcomes in glomerulonephritis

CC chemokine ligand 5/RANTES chemokine antagonists aggravate glomerulonephritis despite reduction of glomerular leukocyte infiltration

The chemokine CC chemokine ligand (CCL)5/RANTES as well as its respective receptor CCR5 mediate leukocyte infiltration during inflammation and are up-regulated early during the course of glomerulonephritis (GN). We tested the effects of the two CCL5/RANTES blocking analogs, Met-RANTES and amino-oxypentane-RANTES, on the course of horse apoferritin (HAF)-induced GN. HAF-injected control mice had proliferative GN with mesangial immune complex deposits of IgG and HAF. Daily i.p. injections of Met-RANTES or amino-oxypentane-RANTES markedly reduced glomerular cell proliferation and glomerular macrophage infiltration, which is usually associated with less glomerular injury and proteinuria in HAF-GN. Surprisingly, however, HAF-GN mice treated with both analogs showed worse disease with mesangiolysis, capillary obstruction, and nephrotic range albuminuria. These findings were associated with an enhancing effect of the CCL5/RANTES analogs on the macrophage activation state, characterized by a distinct morphology and increased inducible NO synthetase expression in vitro and in vivo, but a reduced uptake of apoptotic cells in vivo. The humoral response and the Th1/Th2 balance in HAF-GN and mesangial cell proliferation in vitro were not affected by the CCL5/RANTES analogs. We conclude that, despite blocking local leukocyte recruitment, chemokine analogs can aggravate some specific disease models, most likely due to interactions with systemic immune reactions, including the removal of apoptotic cells and inducible NO synthetase expression.

Patterns of CD4/CD8 T-cell ratio in dialysis effluents predict the long-term outcome of peritonitis in patients undergoing peritoneal dialysis

BACKGROUND

The peritoneal immune compartment is a microenvironment with a particular T-cell repertoire and susceptible to local inflammation. To clarify the role of T lymphocytes in peritoneal immunity, the changes in T-cell subpopulations in peritoneal dialysis effluents (PDEs), and their influence on the response to the treatment of peritonitis and on its prognosis were studied in patients undergoing long-term, continuous ambulatory peritoneal dialysis (CAPD).

METHODS

A cohort of 36 patients treated with CAPD and who had histories of peritonitis were divided into a group with rapid and a group with delayed response to antibiotics, and were followed for 3 years. CD4/CD8 T-cell ratios, T-cell cytokine mRNA expression patterns and transforming growth factor-beta1 (TGF-beta1) concentrations were examined in PDE during bouts of peritonitis. The change in 4 h D/P creatinine during the peritoneal equilibration test (PET) between year 0 and year 3 was expressed as deltaD/P creatinine.

RESULTS

The serial changes in T-cell subsets in PDE during peritonitis showed two patterns: (i) pattern 1, manifest as a progressive increase in the CD4/CD8 ratio, and associated with a rapid response to treatment; and (ii) pattern 2, manifest as a progressive decrease in the CD4/CD8 ratio, and associated with a delayed response to treatment. The major T-cell phenotypes in PDE during peritonitis were Th1-CD4(+) and Tc2-CD8(+), determined by cloning techniques, RT-PCR and double immunofluorescence staining. TGF-beta1 in the effluent was undetectable in pattern 1 after 7-8 days, but remained detectable at 2 weeks in pattern 2. Pattern 2 patients had a significantly greater decrease (deltaD/P creatinine: -0.198+/-0.086) in solute transport than pattern 1 patients (deltaD/P creatinine: -0.036+/-0.077, P<0.05).

CONCLUSIONS

These results suggest that a progressive decrease of the CD4/CD8 ratio in PDE correlates with a persistent expression of TGF-beta1, and plays a pathogenetic role in the evolution of peritonitis, PET deterioration and peritoneal fibrosis. Therefore, patterns of CD4/CD8 T-cell ratio in PDE may predict clinical outcomes of peritonitis in CAPD patients.

The importance of cell-mediated immunity in the course and severity of autoimmune anti-glomerular basement membrane disease in mice

Anti-glomerular basement membrane (GBM) disease is a rapidly progressive glomerulonephritis (GN) resulting from autoimmunity against the Goodpasture antigen alpha3(IV)NC1. In addition to the well-characterized antibody contribution, a T helper 1 (Th1) response has been suspected as the culprit for glomerular injury. We induced anti-GBM disease in DBA/1, C57BL/6, AKR, and NOD mice with recombinant human alpha3(IV)NC1 to investigate the involvement of humoral and cellular autoimmunity. DBA/1 mice had crescentic GN 11 wk postimmunization with alpha3(IV)NC1. C57BL/6 and AKR mice developed a chronic disease course resulting in comparable kidney injury to DBA/1 mice within 6 months. NOD revealed only minor glomerular changes. The rapid course and the severity of the disease in DBA/1 mice can be explained by our immunological findings in their sera and splenocytes: 1) high antibody titers specific for the putative clinically relevant epitope of alpha3(IV)NC1 with Th1-type isotypes, and 2) a strong proliferative response and high amounts of the inflammatory cytokine IFN-gamma, secreted by splenocytes stimulated in vitro with alpha3(IV)NC1, with only low amounts of the anti-inflammatory cytokine IL-10. Our in vivo and in vitro results provide direct evidence that the balance between Th1 and Th2 responses associates with the outcome of anti-GBM disease in mice.

Inflammatory cytokine gene expression in the urinary sediment of patients with lupus nephritis

OBJECTIVE

Lupus nephritis is characterized by intrarenal inflammation and lymphocyte activation. In the present study, the expression of cytokine genes in the urinary sediment of patients with systemic lupus erythematosus (SLE) was examined.

METHODS

We studied 3 SLE patient groups (25 with active lupus nephritis [active group], 25 with inactive SLE and previous renal involvement [remission group], 20 with inactive SLE and no history of renal involvement [nonrenal SLE group]) and 2 control groups (10 patients with noninflammatory renal diseases [non-SLE group] and 10 healthy volunteers [healthy group]). Cytokine gene expression in the urinary sediment was studied by real-time quantitative polymerase chain reaction.

RESULTS

Expression of interferon-gamma (IFNgamma) in urinary sediment was significantly higher in the active group than in all other groups (P < 0.001 by Kruskal-Wallis test). Among the SLE patient groups, there was a close correlation between IFNgamma expression and the overall SLE Disease Activity Index (SLEDAI) score (Spearman's r = 0.590, P < 0.001) and the SLEDAI renal score (r = 0.642, P < 0.001). Urinary expression of interleukin-2 (IL-2) in the active group was significantly higher than that in the healthy group (P = 0.046) but not in the remission or nonrenal SLE groups. There was no difference in the levels of IL-4 expression among the SLE groups.

CONCLUSION

We found a predominance of Th1 cytokine in the urinary sediment of patients with active lupus nephritis. Measurement of cytokine gene expression in urinary sediment may be a useful noninvasive tool for assessing the severity of renal involvement in SLE.

Analyzing the migration of labeled T cells in vivo: an essential approach with challenging features

T cells are involved in the pathogenesis of many diseases. To exert a pathological effect, T cells enter the tissues. We show that the determination of their entry site requires isolation of the respective T cell population, injection into genetically un-manipulated animals, and identification of the cells in vivo at various time points after injection. We indicate variables influencing in vivo migration experiments artificially, and outline how resulting problems can be either avoided or taken into account. Reviewing experiments performed according to the outlined criteria reveals two types of migration patterns for T cell subsets in vivo: 1). Naïve and memory T cells enter lymphoid and non-lymphoid organs in comparable numbers, but selectively accumulate in lymphoid tissues over time, 2). Effector T cells, too, enter lymphoid and non-lymphoid organs in comparable numbers. However, most of them die within 24 hours. Depending on the presence of cytokines, chemokines and extracellular matrix compounds they are able to survive, thereby preferentially accumulating in their target tissues. This information might help to understand the role of migration in the pathogenesis of T cell mediated diseases.

Attenuation of autoimmune disease in Fas-deficient mice by treatment with a cytotoxic benzodiazepine

OBJECTIVE

Elimination of autoreactive cells relies on Fas-dependent activation-induced cell death mechanisms, an important component of peripheral tolerance. Defects in Fas or its cognate ligand lead to inefficient activation-induced cell death and are specific causes of lymphoproliferative and autoimmune diseases. The present study was undertaken to investigate a novel 1,4-benzodiazepine (Bz-423) that induces apoptosis and limits autoimmune disease in NZB/NZW mice, to determine its activity against lupus-like disease associated with defective Fas expression. We investigated the Fas-dependence of its cytotoxic actions, its therapeutic potential in mice deficient in Fas, and its therapeutic mechanism of action.

METHODS

Primary lymphocytes isolated from Fas-deficient MRL/MpJ-Fas(lpr) (MRL-lpr) mice were tested for sensitivity to Bz-423. Bz-423 was administered to MRL-lpr mice for short (1-week) or long (14-week) periods, and its effects on cell survival were determined along with measures of nephritis, arthritis, antibody titers, and Th subpopulations. BALB/c mice were similarly treated to determine if Bz-423 alters normal immune functions in vivo.

RESULTS

Administration of Bz-423 to MRL-lpr mice significantly reduced autoimmune disease including glomerulonephritis and arthritis. Treatment was associated with decreases in CD4+ T cells and an alteration in the Th1/Th2 balance. At the therapeutic dosage, Bz-423 did not interfere with normal T and B cell responses in BALB/c mice, suggesting that this agent is not globally immunosuppressive.

CONCLUSION

Bz-423 is a novel immunomodulatory agent that is active against disease even in the context of defective Fas signaling. It is a leading compound for further investigation into the development of selective therapies for lupus.

Clinicopathological correlation of intrarenal cytokines and chemokines in IgA nephropathy

The pathogenetic mechanisms of IgA nephropathy are diverse and are not yet clearly elucidated. We believe pro-inflammatory cytokines, Th1/Th2, and chemokines would be involved in the pathogenetic pathways and would affect the functional and histological consequences of IgA nephropathy. By using semiquantitative reverse transcriptase-polymerase chain reactions (RT-PCR), we measured the level of intrarenal gene expression of various cytokines and chemokines in 61 renal core biopsy specimens confirmed as IgA nephropathy. And, by using immunohistochemistry (IHC), the degree of expression and the location of various cytokines and chemokines in renal tissues in 29 of the above patients were attempted to be determined. In RT-PCR, the gamma-interferon (IFN-gamma)/interleukin-10 (IL-10) ratio was higher in patients with renal dysfunction than in those with normal renal function. The levels of pro-inflammatory cytokine gene transcripts (tumor necrosis factor-alpha (TNF-alpha), IL-1beta) were high in patients with significant proteinuria. In patients with severe glomerular sclerosis, the ratio of IFN-gamma/IL-10 gene transcripts was high. The level of IL-10 gene transcript was related to the severity of tubular atrophy and interstitial fibrosis. The extent of intrarenal arteriolar lesions correlated with the expression of the IL-8 gene transcript. The degree of IgA deposition in glomeruli was related to the expression of IL-15 and IL-6. In IHC, TNF-alpha, IFN-gamma and IL-2 were immunostained dominantly in the mesangial region, but not in the tubulointerstitial region. In contrast, positive reactions for IL-10 were observed primarily in tubules. Significant reactions for IL-8 were noted in the periarteriolar and arteriolar areas. The results of RT-PCR and IHC showed positive relationships, but these were not statistically significant. This study suggests that pro-inflammatory, Th1/Th2 cytokines and chemokines are involved in the specific processes of inflammation and immunological injury in IgA nephropathy.

Bacterial CpG-DNA aggravates immune complex glomerulonephritis: role of TLR9-mediated expression of chemokines and chemokine receptors

Immune complex glomerulonephritis (GN) often deteriorates during infection with viruses and bacteria that, in contrast to mammals, have DNA that contains many unmethylated CpG motifs. Balb/c mice with horse apoferritin-induced GN (HAF-GN) were treated with either saline, CpG-oligodeoxynucleotides (ODN), or control GpC-ODN. Only CpG-ODN exacerbated HAF-GN with an increase of glomerular macrophages, which was associated with massive albuminuria and increased renal MCP-1/CCL2, RANTES/CCL5, CCR1, CCR2, and CCR5 mRNA expression. CpG-ODN induced a Th1 response as indicated by serum anti-HAF IgG(2a) titers, mesangial IgG(2a) deposits, and splenocyte IFN-gamma secretion. Messenger RNA for the CpG-DNA receptor Toll-like reeptor 9 (TLR9) was present in kidneys with HAF-GN but not in normal kidneys. The source of TLR9 mRNA in HAF-GN could be infiltrating macrophages or intrinsic renal cells, e.g., mesangial cells; but, in vitro, only murine J774 macrophages expressed TLR9. In J774 cells, CpG-ODN induced the chemokines MCP-1/CCL2 and RANTES/CCL5 and the chemokine receptors CCR1 and CCR5. It is concluded that CpG-DNA can aggravate preexisting GN via a shift toward a Th1 response but also by a novel pathway involving TLR9-mediated chemokine and chemokine receptor expression by macrophages, which may contribute to the enhanced glomerular macrophage recruitment and activation. This mechanism may be relevant during infection-triggered exacerbation of human immune-complex GN and other immune-mediated diseases in general.

Brain cytokines and disease

Cytokines (e.g. various interleukins and subfamily members, tumor necrosis factors, interferons, chemokines and growth factors) act in the brain as immunoregulators and neuromodulators. Over a decade ago, the integrative article 'Immunoregulators in the Nervous System' (Neurosci Biobehav Rev 1991; 15: 185-215) provided a comprehensive framework of pivotal issues on cytokines and the nervous system that recently have been extensively studied. Cytokine profiles in the brain, including cytokine generation and action, have been studied in multiple models associated with neuropathophysiological conditions. These include: (1) acute conditions and disorders such as stroke (cerebral ischemia or infarction and intracranial hemorrhage), traumatic brain injury, spinal cord injury and acute neuropathies; (2) chronic neurodegenerative disorders and chronic conditions, including Alzheimer's disease, Parkinson's disease, neuropathic pain, epilepsy and chronic neuropathies; (3) brain infections, including bacterial meningitis and encephalitis; (4) brain tumors; (5) neuroimmunological disorders per se, such as multiple sclerosis; (5) psychiatric disorders, including schizophrenia and depression; (6) neurological and neuropsychiatric manifestations associated with non- central nervous system (CNS) disorders such as peripheral cancer, liver, kidney and metabolic compromise, and peripheral infectious and inflammatory conditions; and (7) cytokine immunotherapy, which can be accompanied by neuropsychiatric manifestations when administered either via peripheral or brain routes. Cytokine profiles have also been studied in multiple animal models challenged with inflammatory, infectious, chemical, malignant and stressor insults. Essentially data show that cytokines play a pivotal role in multiple neuropathophysiological processes associated with different types of disorders and insults. Cytokine expression and action in the brain shows a different profile across conditions, but some similarities exist. Under a defined temporal sequence, cytokine involvement in neuroprotection or the induction of a deleterious pathophysiological cascade and in resolution/healing is proposed depending on the type of cytokine. In the brain, functional interactions among cytokines, balance between pro-inflammatory and anti-inflammatory cytokines and functional interactions with neurotransmitters and neuropeptides play a pivotal role in the overall cytokine profile, pattern of neuropathophysiological cascades, and quality and magnitude of neuropsychiatric manifestations. In this brief review various selected cytokine-related issues with relevance to the brain are discussed.

Effects of CTLA4-Fc on glomerular injury in humorally-mediated glomerulonephritis in BALB/c mice

The effect of cytotoxic T-lymphocyte-associated molecule 4-immunoglobulin fusion protein (CTLA4-Fc) on humorally-mediated glomerulonephritis was studied in accelerated anti-glomerular basement membrane (anti-GBM) glomerulonephritis induced in BALB/c mice. This strain of mice develops antibody and complement dependent glomerulonephritis under this protocol. Sensitized BALB/c mice developed high levels of circulating autologous antibody titres, intense glomerular deposition of mouse immunoglobulin and complement, significant proteinuria, renal impairment, significant glomerular necrosis and a minor component of crescent formation 10 days after challenge with a nephritogenic antigen (sheep anti-GBM globulin). Early treatment during the primary immune response, or continuous treatment throughout the disease with CTLA4-Fc, significantly suppressed mouse anti-sheep globulin antibody titres in serum, and immunoglobulin and complement deposition in glomeruli. The degree of glomerular necrosis was improved and proteinuria was reduced, particularly in the earlier stages of disease. Late treatment by CTLA4-Fc starting one day after challenge with sheep anti-mouse GBM did not affect antibody production and did not attenuate glomerulonephritis. The low level of crescent formation found in BALB/c mice developing glomerulonephritis was not prevented by the administration of CTLA4-Fc. These results demonstrate that CTLA4-Fc is of benefit in this model of glomerulonephritis by its capacity to attenuate antibody production, without affecting the minor degree of cell-mediated glomerular injury.

Predominance of type-2 immune response in idiopathic membranous nephropathy. Cytoplasmic cytokine analysis

BACKGROUND

The Th1/Th2 paradigm is proving increasingly useful in the understanding of infectious diseases and many autoimmune diseases. Th1 cells predominantly produce interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) and are instrumental in initiating delayed-type hypersensitivity and activating macrophages. Th2 cells secrete other cytokines, such as IL-4, IL-5, IL-10 and IL-13 that trigger B-cell activation and immunoglobulin synthesis. It has been shown that in patients with membranous nephropathy, there may be a predominance of Th2, because of the presence of IgG, particularly IgG4, which belongs to a subclass of the type-2 immune response, and complement deposits in glomeruli. In this study, we investigated the immunoresponse of helper T cells, i.e. Th predominance in patients with idiopathic membranous nephropathy.

METHODS

We used flow cytometry to assess the levels of circulating Th cells in patients with idiopathic membranous nephropathy (n = 8) and in normal individuals (n = 23) based on the expression of intracellular type-1 and type-2 cytokines. Because the production of each of these cytokines has a specific time course, we observed the cytokine synthesis at 3, 6, 9 and 12 h after stimulation.

RESULTS

The percentages of IL-2+/CD4+ cells from patients with idiopathic membranous nephropathy were significantly lower than those from normal individuals at 6, 9 and 12 h, with the difference becoming more significant over time. IFN-gamma+/CD4+ cells and IL-4+/CD4+ cells were not significantly different between the two groups. In patients with idiopathic membranous nephropathy, the percentages of IL-10+/CD4+ cells were significantly higher than those in normal individuals at each point in time.

CONCLUSION

Increased IL-10-producing Th cells may lead to suppression of delayed-type hypersensitivity and activate suppressor cells and IgG4 synthesis, resulting in idiopathic membranous nephropathy.

The Wistar Kyoto (RT1(l)) rat is resistant to myelin basic protein-induced experimental autoimmune encephalomyelitis: comparison with the susceptible Lewis (RT1(l)) strain with regard to the MBP-directed CD4+ T cell repertoire and its regulation

Here, we demonstrate that the Wistar Kyoto (WKY/NHsd) rat, which bears the same RT1(l) haplotype as the experimental autoimmune encephalomyelitis (EAE)-susceptible Lewis rat strain, is highly resistant to myelin basic protein (MBP)-induced EAE. No differences between Lewis and WKY strains were found in T cell proliferative specificity or the use of Vbeta8.2 T cell receptors in response to MBP. A Th2 cytokine bias correlated with WKY's EAE resistance. MBP challenge of WKY-into-Lewis adoptive transfer recipients produced a novel biepisodic EAE. The WKY strain should be useful in studies of many tissue-specific autoimmune diseases to which the Lewis rat is susceptible.

IFN-gamma production by intrinsic renal cells and bone marrow-derived cells is required for full expression of crescentic glomerulonephritis in mice

The contribution of IFN-gamma from bone marrow (BM) and non-BM-derived cells to glomerular and cutaneous delayed-type hypersensitivity (DTH) was studied in mice. Chimeric IFN-gamma mice (IFN-gamma(+/+) BM chimera), in which IFN-gamma production was restricted to BM-derived cells, were created by transplanting normal C57BL/6 (wild-type (WT)) BM into irradiated IFN-gamma-deficient mice. BM IFN-gamma-deficient chimeric mice (IFN-gamma(-/-) BM chimera) were created by transplanting WT mice with IFN-gamma-deficient BM. WT and sham chimeric mice (WT mice transplanted with WT BM) developed crescentic glomerulonephritis (GN) with features of DTH (including glomerular T cell and macrophage infiltration) in response to an Ag planted in their glomeruli and skin DTH following subdermal Ag challenge. IFN-gamma-deficient mice showed significant protection from crescentic GN and reduced cutaneous DTH. IFN-gamma(+/+) BM chimeric and IFN-gamma(-/-) BM chimeric mice showed similar attenuation of crescentic GN as IFN-gamma-deficient mice, whereas cutaneous DTH was reduced only in IFN-gamma(-/-) BM chimeras. In crescentic GN, IFN-gamma was expressed by tubular cells and occasional glomerular cells and was colocalized with infiltrating CD8(+) T cells, but not with CD4(+) T cells or macrophages. Renal MHC class II expression was reduced in IFN-gamma(+/+) BM chimeric mice and was more severely reduced in IFN-gamma-deficient mice and IFN-gamma(-/-) BM chimeric mice. These studies show that IFN-gamma expression by both BM-derived cells and intrinsic renal cells is required for the development of crescentic GN, but IFN-gamma production by resident cells is not essential for the development of cutaneous DTH.

FK506 ameliorates proteinuria and glomerular lesions induced by anti-Thy 1.1 monoclonal antibody 1-22-3

BACKGROUND

We have previously reported that CD4 T lymphocytes and their cytokines contribute to development of Thy 1.1 glomerulonephritis (GN). FK506 is reported to suppress the production of Th1 cytokines. The aims of this study were to elucidate the role of Th1 cytokines on mesangial alteration and to examine whether FK506 is available for therapy of mesangial proliferative GN.

METHODS

The effects of daily treatments of FK506 from day -5 and from day +1 of Thy 1.1 GN induction on glomerular alterations were analyzed.

RESULTS

FK506 treatment with 1.0 and 0.3 mg/kg body weight (BW) daily from day 1 to day 4 significantly reduced the glomerular expression of mRNA for interferon-gamma (IFN-gamma; 1.0 mg/kg BW FK506, 32.4% to the placebo group, P < 0.01) and IL-2 (55.6%, P < 0.01) on day 5. FK506 treatment from day -5 of GN induction reduced proteinuria and glomerular alteration in a dose-dependent manner. Although no side effects were detected in rats with 0.3 mg/kg BW of FK506 treatment from day +1, the treatment also ameliorated proteinuria (day 14, 3.7 +/- 0.89 vs. 19.8 +/- 12.3 mg/100 g BW/day P < 0.05) and glomerular alterations [total cell number, 63.1 +/- 3.1 vs. 80.2 +/- 7.4, P < 0.01; matrix expansion, 0.90 +/- 0.30 vs. 1.34 +/- 0.27, P < 0.05; alpha-smooth muscle actin (alphaSMA) expression; 1.20 +/- 0.12 vs. 1.96 +/- 0.29, P < 0.01] on day 14.

CONCLUSION

Th1 cytokines may play an important role in the development of mesangial proliferative glomerulonephritis, and could be targets for therapy. FK506 might be available for clinical use.

IL-15, a survival factor for kidney epithelial cells, counteracts apoptosis and inflammation during nephritis

IL-15, a T cell growth factor, has been linked to exacerbating autoimmune diseases and allograft rejection. To test the hypothesis that IL-15-deficient (IL-15-/-) mice would be protected from T cell-dependent nephritis, we induced nephrotoxic serum nephritis (NSN) in IL-15-/- and wild-type (IL-15+/+) C57BL/6 mice. Contrary to our expectations, IL-15 protects the kidney during this T cell-dependent immunologic insult. Tubular, interstitial, and glomerular pathology and renal function are worse in IL-15-/- mice during NSN. We detected a substantial increase in tubular apoptosis in IL-15-/- kidneys. Moreover, macrophages and CD4 T cells are more abundant in the interstitia and glomeruli in IL-15-/- mice. This led us to identify several mechanisms responsible for heightened renal injury in the absence of IL-15. We now report that IL-15 and the IL-15 receptor (alpha, beta, gamma chains) are constitutively expressed in normal tubular epithelial cells (TECs). IL-15 is an autocrine survival factor for TECs. TEC apoptosis induced with anti-Fas or actinomycin D is substantially greater in IL-15-/- than in wild-type TECs. Moreover, IL-15 decreases the induction of a nephritogenic chemokine, MCP-1, that attracts leukocytes into the kidney during NSN. Taken together, we suggest that IL-15 is a therapeutic for tubulointerstitial and glomerular kidney diseases.

Oral interferon-alpha treatment of mice with cryoglobulinemic glomerulonephritis

Cryoglobulins are associated with the development of a membranoproliferative glomerulonephritis, often referred to as cryoglobulinemic glomerulonephritis, particularly in the setting of hepatitis C virus infection. Parenteral interferon-alpha (IFN-alpha) commonly is used therapeutically in humans with cryoglobulinemic glomerulonephritis. We tested the therapeutic impact of oral IFN-alpha treatment in thymic stromal lymphopoietin (TSLP) transgenic mice, a strain that develops mixed cryoglobulinemia with glomerulonephritis closely resembling the disease that occurs in humans. A total of 41 female mice were treated for 21 days with daily ingestion of either 500 IU of Universal type I IFN or placebo. The studied groups included TSLP transgenic mice treated with IFN-alpha (n = 13), TSLP transgenic mice treated with placebo (n = 13), wild-type mice treated with IFN-alpha (n = 5), and wild-type mice treated with placebo (n = 10). A total of 39 mice completed the study; two TSLP transgenic mice treated with IFN-alpha died during the study period. Placebo-treated TSLP transgenic mice showed significantly increased mean glomerular tuft areas, mean glomerular areas occupied by macrophages, and mean cell numbers per glomerulus compared with wild-type controls. All three parameters were decreased in IFN-alpha-treated TSLP transgenic mice, although the differences compared with placebo-treated mice did not reach significance. The changes in glomerular matrix deposition were the same in IFN-alpha-treated and placebo-treated mice. The oral ingestion of IFN-alpha seemed to reduce glomerular macrophage influx, but this did not result in decreased glomerular matrix deposition. The limited positive effect provides experimental support for clinical studies that indicate the beneficial effects of IFN-alpha therapy observed in humans with glomerulonephritis might be attributable to its antiviral effect rather than modulation of intrarenal pathophysiologic pathways.

The requirement for granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor in leukocyte-mediated immune glomerular injury

Proliferative glomerulonephritis in humans is characterized by the presence of leukocytes in glomeruli. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) can potentially stimulate or affect T cell, macrophage, and neutrophil function. To define the roles of GM-CSF and G-CSF in leukocyte-mediated glomerulonephritis, glomerular injury was studied in mice genetically deficient in either GM-CSF (GM-CSF -/- mice) or G-CSF (G-CSF -/- mice). Two models of glomerulonephritis were studied: neutrophil-mediated heterologous-phase anti-glomerular basement membrane (GBM) glomerulonephritis and T cell/macrophage-mediated crescentic autologous-phase anti-GBM glomerulonephritis. Both GM-CSF -/- and G-CSF -/- mice were protected from heterologous-phase anti-GBM glomerulonephritis compared with genetically normal (CSF WT) mice, with reduced proteinuria and glomerular neutrophil numbers. However, only GM-CSF -/- mice were protected from crescentic glomerular injury in the autologous phase, whereas G-CSF -/- mice were not protected and in fact had increased numbers of T cells in glomeruli. Humoral responses to the nephritogenic antigen were unaltered by deficiency of either GM-CSF or G-CSF, but glomerular T cell and macrophage numbers, as well as dermal delayed-type hypersensitivity to the nephritogenic antigen, were reduced in GM-CSF -/- mice. These studies demonstrate that endogenous GM-CSF plays a role in experimental glomerulonephritis in both the autologous and heterologous phases of injury.

IP-10 and Mig production by glomerular cells in human proliferative glomerulonephritis and regulation by nitric oxide

High levels of expression of mRNA and protein for the chemokines interferon-gamma (IFN-gamma)-inducible protein of 10 kD (IP-10) (CXCL10) and the monokine induced by IFN-gamma (Mig) (CXCL9) were observed, by using in situ hybridization and immunohistochemical analyses, in kidney biopsy specimens from patients with glomerulonephritis (GN), particularly those with membranoproliferative or crescentic GN, but not in normal kidneys. Double-immunostaining or combined in situ hybridization and immunohistochemical analyses for IP-10, Mig, and proliferating cell nuclear antigen (PCNA) or alpha-smooth muscle actin (alpha-SMA) revealed that IP-10 and Mig production by resident glomerular cells was a selective property of glomeruli in which mesangial cells demonstrated active proliferation. IP-10 and Mig mRNA and protein were also expressed by primary cultures of human mesangial cells and human visceral epithelial cells after stimulation with IFN- gamma or with IFN-gamma plus tumor necrosis factor-alpha (TNF-alpha) (which produced greater stimulation). The induction of IP-10 and Mig mRNA and protein expression by IFN-gamma plus TNF-alpha was strongly inhibited by nitric oxide (NO) donors, such as sodium nitroprusside or S-nitroso-N-acetylpenicillamine, but not by cGMP analogues. Electrophoretic mobility shift assays demonstrated that NO donors repressed IP-10 gene transcription induced by IFN-gamma plus TNF-alpha through the inhibition of NF-kappaB activation. These data demonstrate that resident glomerular cells in kidneys of patients with proliferative GN produce large amounts of IP-10 and Mig, which may play important pathogenic roles in this disease. These data also indicate that the production of IP-10 and Mig by human mesangial cells can be downregulated by NO donors through cGMP-independent inhibition of NF-kappaB activation.

New findings in pathogenesis of antineutrophil cytoplasm antibody-associated vasculitis

There has been a profusion of studies related to the pathogenesis of antineutrophil cytoplasm antibody-associated small vessel vasculitis. Further definition of epitopes on the major antigens, proteinase-3 and myeloperoxidase, has been sought, and intracellular signal transduction pathways after antineutrophil cytoplasm antibody-neutrophil interactions are beginning to be explored. Antineutrophil cytoplasm antibody stimulation of neutrophils has highlighted the functional importance of the accelerated death that follows the initial activation. The consequences of neutrophil and monocyte activation for endothelium and tissue damage continue to point toward an inflammatory process that has become dysregulated. Factors that initiate vasculitis are being identified slowly. The most secure identifiable environmental trigger is the antithyroid drug propylthiouracil. It is likely that environmental factors operate against a background genetic susceptibility, and polymorphisms in genes for proteins associated with inflammation are being tested for possible links with small vessel vasculitides.

The Goodpasture antigen is expressed in the human thymus

BACKGROUND

Autoimmunity to kidney antigens causes membranous nephropathy and Goodpasture's disease and very likely is pivotal in many other glomerular diseases. We investigated the potential for central tolerance to the best-characterized kidney autoantigen, the NC1 domain of the alpha3 chain of type IV collagen [alpha3(IV)NC1], which is the target of autoimmune attack in Goodpasture's disease.

METHODS

Indirect immunofluorescence on human thymus and polymerase chain reaction (PCR) and Southern blot analysis of cDNA reverse transcribed from RNA extracted from human thymus and kidney.

RESULTS

Indirect immunofluorescence on human thymus demonstrated the presence of alpha3(IV)NC1 in all six thymus samples examined. The homologous collagen IV chain, alpha5(IV)NC1, also was detected with a similar intra-thymic distribution. Strikingly, thymic alpha3 and alpha5 localized around and within Hassall's corpuscles in the thymic medulla, which are structures implicated in T cell apoptosis and possibly negative selection. In contrast, alpha1(IV)NC1 localized to the basement membranes of interlobular septa and blood vessels, as is typical of collagen IV chains situated outside the thymus. Reverse transcription-polymerase chain reaction (RT-PCR) confirmed the presence of mRNA encoding alpha3(IV)NC1 and alpha5(IV)NC1 in thymic tissue establishing that the antigens were likely to have been synthesized locally.

CONCLUSIONS

The results demonstrate that alpha3(IV)NC1 is expressed in the human thymus, and therefore should be available for induction of alpha3(IV)NC1-specific tolerance. This observation has the important implication that patients' alpha3(IV)NC1-specific, autoreactive T cells are more likely to recognize cryptic epitopes that are not adequately presented by thymic antigen-presenting cells (APC) than the major antigen-derived epitopes generally identified by conventional approaches.

Podocyte bridges between the tuft and Bowman's capsule: an early event in experimental crescentic glomerulonephritis

Although experimental crescentic glomerulonephritis starts with an endocapillary inflammation, the crescents themselves seem to originate from the proliferation of parietal epithelial cells (PEC). In this study, an attempt was made to disclose a link between the two processes by a morphologic analysis of early stages of the disease. Mice were immunized with rabbit IgG in complete Freund's adjuvant on day -6. At day 0, they received an intravenous injection of a rabbit antiglomerular basement membrane serum. On days 3, 6, and 10, the kidneys were fixed by vascular perfusion for examination by light and electron microscopy. On day 3, morphologic alterations affected mainly the endocapillary compartment; most podocytes appeared to be intact. On day 6, alterations of podocytes were widespread, including foot process effacement and prominent microvillous transformation, and some crescents were found. On day 10, crescents were found in 40% of glomeruli. The most surprising finding was podocytes that adhered to both the glomerular basement membrane and the parietal basement membrane, thus forming bridges between the tuft and Bowman's capsule. Those podocyte bridges were sparse on day 3 but were regularly encountered on days 6 and 10 in glomeruli without crescents and also as a component of crescents. They were interposed between PEC and later between the cells of a crescent without formation of junctional connection with these cells. It is proposed that the spreading of podocytes on the parietal basement membrane represents a lesion of the parietal epithelium and that this process initiates the proliferation of PEC to form a crescent.

Effects of type 2 cytokines on glomerular epithelial cells

Visceral glomerular epithelial cells (GECs) are involved in the maintenance of the filtration barrier and may play a role in immune responses. Cytokines may act on GECs and we wished to test this in vitro. Vascular endothelial growth factor (VEGF) is a specific product of the GEC that may play a role in glomerular permeability. We have investigated whether GECs in culture express receptors for interleukin (IL)-4, 10 and 13 (often grouped together as type 2 cytokines) and whether these cytokines alter GEC VEGF production. Type 2 cytokines were compared to transforming growth factor-beta (TGF-beta) and IL-1beta which are known to upregulate VEGF production. GECs were grown from human nephrectomy specimens and cultured with and without the addition of exogenous cytokines. Messenger RNA data demonstrated the presence of IL-4 receptor alpha, IL-10 receptor 1 and 2, and IL-13 receptors alpha1 and alpha2. However, at the protein level by flow cytometry, only IL-13 alpha2 could be consistently demonstrated. IL-4, IL-10 and IL-13 inhibited production of VEGF but did not affect the pattern of isoform expression. In contrast, TBF-beta and IL-1beta caused an increase in VEGF production. These effects were not explained by effects on proliferation. Our data provide evidence that GECs express receptors for type 2 cytokines and that these cytokines can act directly on GECs, to decrease VEGF production.

Th2 predominance at the single-cell level in patients with IgA nephropathy

BACKGROUND

Abnormalities of lymphocyte function have been reported to be involved in the pathogenesis of IgA nephropathy (IgA-N). The aim of this study was to investigate helper T (Th) predominance at the single-cell level, one of the abnormalities of lymphocyte function in IgA-N.

METHODS

Using flowcytometry, we assessed the levels of circulating Th cells in IgA-N patients (n=30), and in normal individuals (n=30) based on the expression of intracellular Th1 cytokines for interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), and of intracellular Th2 cytokines for IL-4, IL-10, and IL-13. Because the production of each cytokine had a specific time course, we examined cytokine synthesis at 3, 6, 9, and 12 h after stimulation.

RESULTS

The percentages of IL-2-positive Th cells from IgA-N patients were significantly lower than in normal individuals at 6, 9, and 12 h, with the difference becoming greater with time. The number of IFN-gamma-positive Th cells in IgA-N patients was significantly lower than in normal individuals at 9 h, and the number of IFN-gamma-positive Th cells increased more at 12 h than at 3 h in both groups. IL-4 and IL-13 expression was increased in patients with IgA-N at 6 h compared with normal individuals. In IgA-N patients, the percentage of IL-10-positive Th cells was significantly higher than that in normal individuals at each time-point.

CONCLUSION

A polarization toward Th2 response at the stimulated lymphocyte level may lead to immune abnormalities in IgA-N.

Elevated interleukin-18 levels in the urine of nephrotic patients

BACKGROUND/AIM

The etiology of minimal-change nephritic syndrome (MCNS) is obscure. It has been speculated that T cells play a role in the pathogenesis of MCNS. Interleukin (IL)-18, a novel immunoregulatory cytokine with potent inferon-gamma-inducing activities, may play an important role in T-helper type 1-mediated immune responses. To examine further the possible role of IL-18 in nephrotic syndrome (NS), in the present study we measured IL-18 levels in the urine in different clinical stages of MCNS. The aim of this study was to investigate the involvement of IL-18 in MCNS.

METHODS

Urine samples were obtained from 20 MCNS patients. The disease controls included 20 patients with IgA nephropathy. The samples were assayed for IL-18 protein by a sandwich enzyme-linked immunosorbent assay.

RESULTS

Compared with normal controls, significantly increased urinary levels of IL-18 were detected in MCNS patients with the NS. The urinary IL-18 (uIL-18) levels correlated with the degree of proteinuria in MCNS patients. Moreover, when individual MCNS patients were followed through their clinical illness, uIL-18 levels were increased during the active phase and decreased as the patients went into remission.

CONCLUSIONS

These results indicate that uIL- 18 is detectable in a subgroup of patients with active NS and correlates to their disease activity in patients with MCNS. Our findings support the notion that IL-18 may play a role in the pathophysiology of NS.

Membranous glomerulonephritis after haematopoietic cell transplantation for multiple myeloma

Renal involvement during graft-versus-host disease following haematopoietic cell transplantation for multiple myeloma has never been described. We report a case of a recipient who developed nephrotic syndrome and membranous glomerulonephritis 22 months after the graft and 6 months after cyclosporine withdrawal. Symptoms resolved when immunosuppressive therapy was reinstituted.

Chemokines in renal diseases

The interaction of activated leukocytes and renal resident cells is thought to play a crucial role in the pathogenesis of renal diseases. Recent investigations of the pathophysiological roles of chemokines and their cognate receptors have shed light on the detailed molecular mechanisms of leukocyte trafficking and activation in the diseased kidneys. Chemokine/chemokine receptor systems may be essentially involved in the pathogenesis of phase-specific renal disorders and the measurement of urinary levels of chemokines may be clinically useful for monitoring the different disease phases and activities. In addition, chemokine receptors expressed in renal resident cells may be involved in proliferation, fibrogenesis, as well as chemotaxis. The selective intervention of chemokine/chemokine receptor systems (anti-chemokine therapy) may have the potential as the particular therapeutic strategies for renal diseases in future.

Upregulation of fractalkine in human crescentic glomerulonephritis

BACKGROUND/AIM

To evaluate the importance of fractalkine, a novel member of the CX3C chemokine, and natural killer (NK) cells in human crescentic glomerulonephritis, we determined the presence of fractalkine in the diseased kidneys immunohistochemically, and the correlation among fractalkine, NK cells and the degree of renal damage.

METHODS

Twenty-three patients (13 males and 10 females) with primary or secondary crescentic glomerular disease were evaluated in this study. Fractalkine and CD16-positive cells including NK cells were detected immunohistochemically.

RESULTS

Fractalkine-positive cells were detected in the interstitium of 23 patients with crescentic glomerulonephritis, while they were not detected in the glomeruli. In addition, CD16-positive cells were detected in both the glomeruli (1.3 +/- 0.2/glomerulus) and interstitium (1.3 +/- 0.2/visual field). The number of fractalkine-positive cells in the interstitium correlated with the number of CD16-positive cells before glucocorticoid therapy (r = 0.43, p = 0.047, n = 23). The number of fractalkine-positive cells in the interstitium before glucocorticoid therapy (0.2 +/- 0.1/visual field) decreased after therapy (0.1 +/- 0.1/visual field, p = 0.050) in 11 cases tested. The number of CD16-positive cells in the diseased kidneys did not change after glucocorticoid therapy.

CONCLUSION

These results suggest that the local production of fractalkine may explain the presence of CD16-positive cells including NK cells, which may participate in the interstitial lesions of human crescentic glomerulonephritis before corticoid therapy.

Signal transduction by the chemokine receptor CXCR3: activation of Ras/ERK, Src, and phosphatidylinositol 3-kinase/Akt controls cell migration and proliferation in human vascular pericytes

Hepatic stellate cells (HSC) and glomerular mesangial cells (MC) are tissue-specific pericytes involved in tissue repair, a process that is regulated by members of the chemokine family. In this study, we explored the signal transduction pathways activated by the chemokine receptor CXCR3 in vascular pericytes. In HSC, interaction of CXCR3 with its ligands resulted in increased chemotaxis and activation of the Ras/ERK cascade. Activation of CXCR3 also stimulated Src phosphorylation and kinase activity and increased the activity of phosphatidylinositol 3-kinase and its downstream pathway, Akt. The increase in ERK activity was inhibited by genistein and PP1, but not by wortmannin, indicating that Src activation is necessary for the activation of the Ras/ERK pathway by CXCR3. Inhibition of ERK activation resulted in a decreased chemotactic and mitogenic effect of CXCR3 ligands. In MC, which respond to CXCR3 ligands with increased DNA synthesis, CXCR3 activation resulted in a biphasic stimulation of ERK activation, a pattern similar to the one observed in HSC exposed to platelet-derived growth factor, indicating that this type of response is related to the stimulation of cell proliferation. These data characterize CXCR3 signaling in pericytes and clarify the relevance of downstream pathways in the modulation of different biologic responses.

Development and fate of crescentic and granulomatous lesions in rat Masugi nephritis

It has been observed that with Masugi nephritis in Wistar rats the initiation of endocapillary proliferative changes with macrophage accumulation is usually followed by glomerular sclerosis without extracapillary extension. In the present study, the provocation of an extracapillary lesion was attempted using accelerated Masugi nephritis in Wistar-Kyoto rats. In order to accelerate the accumulation of monocyte/macrophages, the administration of methylcellulose was added in an additional group. The development and fate of extracapillary lesions were analyzed histopathologically and immunohistochemically. As a result, the formation of extracapillary proliferation of granulomatous lesions could be initiated in this model. Granulomatous lesions were composed of CD4+ T cells and CD8+ T cells and monocyte/macrophages including multinucleated giant cells. These inflammatory cells had seemingly escaped from the capillary lumen through the injured glomerular basement membrane and formed cellular and granulomatous crescents. In addition, tenascin was strongly expressed in cellular crescents and was a unique extracellular matrix at this cellular stage. The cellular crescents then progressed to sclerosis with the formation of increased collagenous extracellular matrix. These results suggest that a delayed-type hypersensitivity plays a role in granulomatous crescent formation, even though the initial glomerular injury was evoked by a humoral antibody.

Th1/Th2 predominance and proinflammatory cytokines determine the clinicopathological severity of IgA nephropathy

BACKGROUND

IgA nephropathy is one of the most common forms of primary glomerulonephritis in adults. Its pathogenesis is complex. The nature of infiltrating and proliferating cells and of cellular mediators could contribute to the progression of IgA nephropathy towards end-stage renal failure.

METHODS

To evaluate this hypothesis, we attempted to quantify the magnitude of intrarenal gene expression of various cytokines (IL-1 beta, TNF-alpha, IL-6, IL-15, IL-2, IFN-gamma, IL-10) and chemokines (IL-8, RANTES, MCP-1) in 48 renal core biopsy specimens, diagnosed as IgA nephropathy by immunofluorescence microscopy. Semi-quantitative reverse-transcriptase polymerase chain reaction using internal competitors was used for the quantification of gene transcripts.

RESULTS

The expression of intrarenal gene transcripts of various cytokines and chemokines was closely interrelated, but not associated with the pathological grading system. The IFN-gamma/IL-10 ratio was higher in patients with renal dysfunction than in those with normal renal function (P=0.0483). Gene transcript levels of proinflammatory cytokines were related to the amount of proteinuria. In patients with severe glomerular sclerosis, the ratio of IFN-gamma/IL-10 gene transcripts was high (P=0.04). IL-10 gene transcript level was related to the severity of tubulointerstitial damage. The levels of gene expression of IL-10 (P=0.009), IFN-gamma (P=0.03), and TNF-alpha (P=0.005) were related to the degree of mesangial matrix expansion and the extent of intrarenal arteriolar changes correlated with the expression of the IL-8 gene transcript (r=0.43, P=0.004).

CONCLUSIONS

We propose that Th1/Th2 predominance and the level of proinflammatory cytokines could determine the pathogenetic processes and the severity of the clinical manifestations of IgA nephropathy.

Augmented interleukin-18 production by peripheral blood monocytes in patients with minimal-change nephrotic syndrome

BACKGROUND/AIM

The etiology of minimal-change nephrotic syndrome (MCNS) is poorly understood. It has been proposed that cell-mediated immunity and T-cell activation are key features of this glomerular disease. Interleukin (IL)-18, a novel interferon-gamma-stimulating factor, may act as an important effector molecule involved in various immune responses. To our knowledge, very little is known about the involvement of IL-18 in NCNS. The aim here was to define further the involvement of IL-18 in MCNS.

METHODS

To understand the role of this cytokine, in vitro IL-18 levels were analyzed by a sensitive enzyme-linked immunosorbent assay (ELISA) method in 16 patients with MCNS who were either in a stable or active condition. The disease controls included 16 patients with IgA nephropathy (IgAN). The IL-18 levels were compared with values in healthy controls.

RESULTS

Significantly increased spontaneous and lipopolysaccharide (LPS)-stimulated production of IL-18 was detected in peripheral blood monocyte (PBM) cultures of MCNS patients with the nephrotic syndrome (NS) as compared with those of normal controls. Moreover, when individual MCNS patients were followed through their clinical illness, IL-18 levels were increased during the active phase and normalized as the patients went into remission. The amounts of IL-18 are significantly correlated with the levels of vascular permeability factor (VPF) in MCNS patients.

CONCLUSIONS

Thus, in MCNS patients, the level of IL-18 was increased and this increase was related to the activity of this disease. The data provide circumstantial evidence for a role of IL-18 in MCNS.

Leukocyte responses in two breeds of layer chicken that differ in susceptibility to induced amyloid arthropathy

Amyloid arthropathy in chicken can be induced by intravenous inoculation of an arthropathic and amyloidogenic Enterococcus faecalis in susceptible breeds. The commercial brown layer hybrids (BL) are more susceptible to the disease compared to their white counterparts (WL). The precursor of amyloid-A protein, which is serum amyloid-A (SAA), is identical in WL and BL. To investigate the factors involved in the breed-restricted susceptibility to amyloid arthropathy, we studied the type of leukocyte response and inflammatory reactions in E. faecalis-induced disease. In the BL, a significant dose dependent peripheral leukocytosis mainly by heterophils, and plasma cell infiltration in arthritic joints was found. In contrast, secondary lymphoid nodular aggregates in the synovial membrane were prominent in the WL. The aggregates consisted mainly of CD8+ T cells. The high number of circulating leukocyte and prolific plasma cell responses in the BL predict extensive humoral and acute phase reactions. This is in agreement with literature data on suppressed T-cell function in casein-induced amyloid-susceptible mice strains. The difference in leukocyte response and type of inflammation between WL and BL, when arthropathic and amyloidogenic bacteria induce infection, in conjunction with susceptibility to amyloid arthropathy, is discussed in view of the murine T-helper responses.

Chemokines as therapeutic targets in renal disease

Increased understanding of the fundamental importance of the role of chemokines and their receptors in inflammation, together with the demonstration of their involvement in human and experimental inflammatory renal disease, make these molecules potential therapeutic targets. A number of recent studies using genetically deficient mice and chemokine receptor antagonists in animal models have demonstrated that chemokine inhibition can attenuate experimental renal injury. Because there is simultaneous expression of multiple chemokines and receptors in disease, strategies that are aimed at antagonizing multiple chemokines receptor interactions are likely to be more effective than therapies that target a single chemokine. It is also now recognized that chemokines are involved in normal immune development and immune regulation. These observations, together with the results of studies that have demonstrated deleterious effects of chemokine receptor antagonism in experimental renal disease, highlight the need for thorough understanding of the role of individual chemokines in the pathogenesis of different types of renal disease before optimal therapeutic interventions may be achieved.

Regulatory interactions of alphabeta and gammadelta T cells in glomerulonephritis

BACKGROUND

Several lines of evidence suggest that cellular immune mechanisms contribute to glomerulonephritis.

METHODS

The roles of alphabeta and gammadelta T cells in the pathogenesis of glomerulonephritis were investigated in a model of nephrotoxic nephritis in mice deficient in either T-cell population [T-cell receptor (TCR)beta and TCRdelta knockout mice]. The model, induced by the injection of rabbit anti-mouse glomerular basement membrane antibody, is characterized by the development of proteinuria and glomerular damage over a 21-day observation period in wild-type mice.

RESULTS

Mice deficient in either alphabeta or gammadelta T cells developed minimal proteinuria and glomerular lesions and had a significant reduction in macrophage accumulation compared with wild-type mice. In gammadelta T-cell-deficient mice, circulating levels and glomerular deposition of autologous IgG were comparable to wild-type levels, while alphabeta T-cell-deficient mice had no autologous IgG production. Autologous antibody production was not required for the development of glomerulonephritis since mice that lack IgG and B cells (micro-chain-/-) developed similar proteinuria to that observed in wild-type mice.

CONCLUSIONS

These studies suggest a proinflammatory role for both alphabeta and gammadelta T cells in glomerular injury, independent of the humoral response. This is the first demonstration, to our knowledge, that both T-cell subsets contribute to the progression of a disease, and it suggests that complex regulatory interactions between alphabeta and gammadelta T cells play a role in glomerular injury.

Properties of HLA class II molecules divergently associated with Goodpasture's disease

Goodpasture's disease provides an opportunity to analyse molecular mechanisms that may underlie MHC class II associations with autoimmune disease because it is caused by autoimmunity to a defined antigen [the 230 amino acid NC1 domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1)] and has strong HLA class II associations. We compared the alpha3(IV)NC1 peptide binding of class II molecules with strong positive (DR15) and dominant negative (DR7/1) associations using an inhibition binding assay and short synthetic peptides spanning the sequence of alpha3(IV)NC1. DR15 in general bound the peptides with low affinity (three of 23 < 100 nM) compared to DR1 and DR7 (12 and 10 < 100 nM respectively), and no peptide bound DR15 with much higher affinity (>10-fold) than both DR1 and DR7. Thus DR15 molecules are unlikely to increase susceptibility to Goodpasture's disease by presenting a particular alpha3(IV)NC1-derived peptide uniquely well and DR1/7 are unlikely to protect by their inability to present particular peptides. However DR1/7 could protect by capturing alpha3(IV)NC1 peptides and preventing their display bound to DR15; the binding data suggest that all the major (biochemically detectable) alpha3(IV)NC1 peptides presented bound to DR15 by DR15 homozygous antigen-presenting cells (APC) would bind preferentially to DR1/7 in DR15, 1/7 heterozygote APC.

Distinct expression of CCR1 and CCR5 in glomerular and interstitial lesions of human glomerular diseases

We investigated the presence of CCR1- and CCR5-positive cells immunohistochemically in the kidneys of 38 patients with several renal diseases, including 13 crescentic glomerulonephritis patients. In addition, we determined cell phenotypes of CCR1- and CCR5-positive cells using a dual immunostaining technique. Urinary levels of their ligands, for CCR1 and CCR5; macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and regulated upon activation in normal T cells expressed and secreted (RANTES) were evaluated by enzyme-linked immunosorbent assay. CCR1- and CCR5-positive cells were detected in both glomeruli and interstitium of the diseased kidneys. Using a dual immunostaining technique, these positive cells were CD68-positive macrophages (MPhi) and CD3-positive T cells. The number of CCR1-positive cells in glomeruli was correlated with urinary levels of MIP-1alpha. The number of CCR1-positive cells in the interstitium was correlated with both urinary MIP-1alpha and RANTES levels. CCR1-positive cells in the interstitium remained after glucocorticoid therapy, most of which were MPhi, and were correlated with the intensity of interstitial fibrosis and tubular atrophy. Glomerular CCR5-positive cells were well correlated with extracapillary lesions and urinary MIP-1alpha levels, while interstitial CCR5-positive cells, mainly CD3-positive T cells, were correlated with interstitial lesions and urinary RANTES levels. Renal CCR5-positive cells were dramatically decreased during convalescence induced by glucocorticoids. These results suggest that chemokine receptor signaling may be pivotal for human renal diseases through the recruitment and activation of MPhi and T cells; CCR5-positive cells may participate in glomerular lesions including extracapillary lesions via MIP-1alpha and in interstitial lesions via RANTES. CCR1 may be involved in interstitial lesions in resolving phase after glucocorticoid therapy.

An anti-CD5 monoclonal antibody ameliorates proteinuria and glomerular lesions in rat mesangioproliferative glomerulonephritis

BACKGROUND

Increased numbers of lymphocytes have been identified in biopsy specimens of human mesangial proliferative glomerulonephritis (GN). However, the causal relationship between infiltrating T lymphocytes and mesangial changes in mesangial proliferative GN has not been previously evaluated. In this study, we elucidated the role of lymphocytes in the development of mesangial proliferative GN.

METHOD

Immunohistological and flow cytometric analyses as well as a reverse transcription-polymerase chain reaction (RT-PCR) studies were performed in monoclonal antibody (mAb) 1-22-3-induced Thy 1.1 GN. To elucidate the role of these lymphocytes, depletion studies were carried out using anti-CD8 mAb (OX-8), which depletes both CD8+ T lymphocytes and natural killer (NK) cells and anti-CD5 mAb (OX-19), which depletes both CD4+ and CD8+ T lymphocytes.

RESULTS

Immunofluorescence (IF) studies revealed that NK cells and CD4+ T lymphocytes were recruited into glomeruli. Glomerular mRNA expression for interferon-gamma, interleukin-2 (IL-2), IL-10, and perforin increased after induction of GN. Increased expressions of several chemokines, which have the potential to attract lymphocytes, were also detected. Anti-CD8 mAb treatment completely prevented the recruitment of NK cells; however, it had no protective effect on proteinuria and mesangial injury. By contrast, anti-CD5 mAb treatment suppressed the recruitment of CD4+ T lymphocytes into glomeruli and reduced proteinuria (60.4 +/- 25.7 vs. 120.0 +/- 32.3 mg/day, P < 0.05) and mesangial changes evaluated by total number of cells in glomeruli (63.2 +/- 6.0 vs. 81.4 +/- 5.9, P < 0.01) and alpha-smooth muscle actin staining score (1.4 +/- 0.2 vs. 2.2 +/- 0. 4, cf2eth P < 0.01) on day 14 after induction of GN. mRNA expression for IL-2 was significantly reduced by OX-19 treatment.

CONCLUSION

T lymphocytes participate in the development of mesangial proliferative GN.

Pathogenesis of ANCA-associated systemic vasculitis

The aetiology of primary systemic vasculitides remains unknown. Recent advances have been made in the understanding of relevant mechanisms of inflammation, particularly the role of the endothelium and interactions with inflammatory mediators and immune effector cells. In Wegener's granulomatosis and microscopic polyangiitis the evidence suggests an autoimmune inflammatory process, characterized by an early lesion involving neutrophils and endothelial cells as both targets and active participants; priming of neutrophils and endothelial cells allows ANCA to activate neutrophils with damage localized to the endothelium. In the absence of immune complex deposition, the role of the ANCA is particularly intriguing. Endothelial cell damage and activation produces pro-inflammatory mediators with influx monocytes and T cells intensifying damage. Increased understanding of the pathogenesis of systemic vasculitis is likely to provide the basis for the use of more selective immunomodulatory therapies in the future.

Chemokines, chemokine receptors, and renal disease: from basic science to pathophysiologic and therapeutic studies

Leukocyte trafficking from peripheral blood into affected tissues is an essential component of the inflammatory reaction to virtually all forms of injury and is an important factor in the development of many kidney diseases. Advances in the past few years have highlighted the central role of a family of chemotactic cytokines called chemokines in this process. Chemokines help to control the selective migration and activation of inflammatory cells into injured renal tissue. Chemokines and their receptors are expressed by intrinsic renal cells as well as by infiltrating cells during renal inflammation. This study summarizes the in vitro and in vivo data on chemokines and chemokine receptors in renal diseases with a special focus on potential therapeutic effects on inflammatory processes.

Circulating antibodies against alpha-enolase in patients with primary membranous nephropathy (MN)

MN is characterized by the glomerular deposition of IgG4 immune complexes. This suggests that nephritogenic immune responses in MN are of the Th2 T helper cell type; however, the pathogenesis of MN is still unknown. In this study we examined sera from patients with primary MN for antibodies to renal proteins. A 47-kD protein in both human and porcine renal extracts was found by immunoblotting to react specifically with serum IgG from some patients. This protein was purified from porcine kidney and identified as alpha-enolase on the basis of its partial amino acid sequences. Sera from 87 patients with primary MN, 24 patients with secondary MN (15 rheumatoid arthritis patients, nine systemic lupus erythematosus patients), and 16 healthy subjects were examined by ELISA using purified alpha-enolase. In 60 (69%) patients with primary MN and 14 (58%) patients with secondary MN, the measured optical density values, and hence serum anti-alpha-enolase antibody levels, were greater than the mean + 2 s.d. of healthy subjects. Immunoblot analysis showed that IgG1 or IgG3 was the predominant subclass (Th1 T helper cell type subclass) of antibodies against alpha-enolase in patients with primary and secondary MN. Since circulating antibodies against alpha-enolase have recently been reported in patients with various autoimmune disorders, our results suggest that a number of patients with presumed primary MN may also have abnormalities in Th1 T helper cell-mediated immune responses.