Linear glomerular IgG fixation in renal allografts: incidence and significance in Alport's syndrome

Twelve of 767 renal allograft recipients developed linear fixation of IgG along the glomerular basement membrane (GBM) by direct immunofluorescence technique. This was associated with linear fixation along the tubular basement membrane in 7 of them. Circulating anti-GBM antibodies were not detected by indirect immunofluorescence or radioimmunoassay in any patient whereas anti-TBM antibodies were found in 2 of 4 with linear TBM fixation. Among the 12 patients with linear GBM fixation, 5 had Alport's syndrome; the 7 others had various renal diseases, excluding anti-GBM nephritis. Among the 767 patients, 34 had Alport's syndrome or variants (i.e., 4.5%). The incidence of linear GBM fixation is much higher in Alport's syndrome than in other renal diseases. Linear GBM fixation was not clearly related to anti-GBM antibodies and was not accompanied by significant deterioration of graft function. These findings may be relevant, however, to the missing GBM antigen in Alport's syndrome.     

Tubulointerstitial immune complex nephritis in a patient with systemic lupus erythematosus: role of peritubular capillaritis with immune complex deposits in the pathogenesis of the tubulointerstitial nephritis

Class IV-G (A/C) diffuse lupus nephritis and tubulointerstitial (TI) nephritis in a 31-year old woman was studied by light, immunofluorescence (IF), and electron microscopy (EM), to determine the pathogenesis of the TI lesions. The light microscopic findings showed peritubular capillaritis in the interstitium, with ruptures in the capillary structure, lysis of the surrounding tubular basement membrane (TBM), extravasated red blood cells (RBCs), the infiltration of neutrophils and mononuclear cells, and edema. The IF study revealed IgG, IgA, IgM, C1q, C3, and C4 depositions along the TBM, on the capillary walls, and in the interstitium proper. The EM study disclosed the deposition of immune complexes in the TBM, the capillary wall, and the interstitium proper. Based on these findings, the TI nephritis in this patient was considered to be due to peritubular capillaritis secondary to the immune complex depositions in the capillary wall of the interstitium.     

Role of antibodies directed against tubular basement membranes in human renal transplantation

Direct immunofluorescence studies of graft biopsies from 662 renal transplant recipients demonstrated linear IgG deposition along tubular basement membranes (TBM) in 18 cases. In ten of them, circulating anti-TBM antibodies, whose detectable levels varied from 1/4 to 1/100, were demonstrated by indirect immunofluorescence on normal human kidneys. These antibodies reacted with every human kidney tested and in two cases, it could be demonstrated that they recognized the TBM of the patient's own end-stage kidney. Hence, they reacted as autoantibodies. Circulating anti-TBM antibodies were detected within the first 6 months after transplantation, remained present for an average of 3 months, and never recurred once they had disappeared. Serial biopsies demonstrated the loss of IgG linear fixation on TBM. Neither tubular nor interstitial injury was significantly associated with the presence of anti-TBM antibodies, and the transplant survival was not different in these patients who developed anti-TBM antibodies compared to our entire population of transplant biopsies.     

Experimental gold nephropathy in guinea pigs: detection of autoantibodies to renal tubular antigens

Renal tubular dysfunction was induced in Hartley guinea pigs by injection of sodium aurothiomalate (gold) as manifested by excretion of tubular basement membrane (TBM) antigen and renal tubular epithelial (RTE) antigen in urine and tubular proteinuria. Following the tubular dysfunction, autoimmune tubulointerstitial nephritis (TIN) and/or immune complex nephropathy (ICN) developed in a large proportion of animals. TIN was associated with anti-TBM antibodies, and the histological features were characterized by tubular lesions with interstitial mononuclear cell infiltration, destruction of tubules, and interstitial fibrosis. In ICN, the glomerular lesions consisted of partial thickening of capillary walls and mesangial cellularity, and granular immune deposits were seen in the mesangial area and on capillary walls. Furthermore, electron-dense deposits were demonstrated in the mesangial area and in the glomerular basement membrane (GBM) by electron microscopy. Anti-RTE antibodies were detected in the sera and eluates from the kidney of animals with ICN. RTE antigens were also detected in the glomerular deposits by indirect immunofluorescence using anti-guinea pig RTE antibody. These results suggest that TBM and RTE antigens released from renal tubules damaged by a direct toxic action of gold may lead to antibody formation against these antigens and induce TIN and/or ICN.     

Predominant tubulointerstitial nephritis in a patient with systemic lupus erythematosus: phenotype of infiltrating cells

A 63-year-old man with systemic lupus erythematosus developed tubular proteinuria. All subclasses of serum IgG increased, and the largest IgG subclass increase was IgG4. A renal biopsy showed lupus nephritis (Class II) with severe tubulointerstitial nephritis (so-called predominant tubulointerstitial lupus nephritis, an unusual form of lupus nephritis). Immunofluorescence microscopy revealed positive granular staining for IgG, C3 and C1q in the mesangium and peritubular interstitium, and along the tubular basement membranes (TBM). Electron microscopy also showed electron-dense deposits in the mesangium and TBM. Immunophenotyping of interstitial infiltrating cells disclosed a predominance of T cells. CD8-positive cytotoxic T cells infiltrated the peritubular interstitium, and some of these cells infiltrated the tubules. B cell-rich lymphoid follicles were also observed. IgG subclass analyses showed glomerular IgG1, IgG2 and IgG4 deposition, positive staining of IgG4 in the peritubular interstitium and along the TBM, and abundant IgG1-, IgG3- and IgG4-positive plasma cells in the interstitium. The patient responded well to moderate-dose steroid therapy. This is the first report of immunophenotyping of interstitial infiltrates in predominant tubulointerstitial lupus nephritis. The results suggest CD8-positive cytotoxic T cell-mediated tubular injury. Furthermore, immune complexes containing IgG4 might be one of etiologic factors.     

Antitubular basement membrane antibodies in renal allograft rejection.

In a patient with an episode of acute renal allograft rejection, antibodies to tubular basement membranes (TBM) were noted by direct immunofluorescence in a renal biopsy and by indirect immunofluorescence in the serum. The serum antibodies decreased gradually and became undetectable 3 months after the rejected kidney was removed. Anti-RBM antibodies eluted from the rejected kidney were capable of binding in vitro to TBM but not to glomerular basement membranes (GBM) in 39 of 40 human kidneys and various animal kidneys. The specificity was confirmed by blocking studies showing inhibition with ultrasonicated human TBM but not with GBM preparations. Passive transfer experiments showed that anti-TBM antibodies were able to bind in vivo to normal rabbit kidneys, although they could not elicit an inflammatory response. The possible mechanisms of production of anti-TBM antibodies and their potential significance in graft loss are discussed.     

Experimental autoimmune glomerulonephritis induced by homologous and isologous glomerular basement membrane in Brown-Norway rats

In order to study disease mechanisms and potential forms of therapy in glomerulonephritis, a model of experimental autoimmune glomerulonephritis (EAG) has been developed in the rat. We have examined the response of Brown-Norway (BN) rats to a single i.m. injection of collagenase-solubilised homologous (Sprague-Dawley, SD) or isologous (BN) glomerular basement membrane (GBM), with and without complete Freund's adjuvant (CFA). There was a dose-dependent circulating anti-GBM antibody response to all preparations of rat GBM. Animals given either antigen alone at a dose of 2 mg/kg developed circulating anti-GBM antibodies, which reached peak values by 6 weeks (63 +/- 5% following SD GBM; 53 +/- 8% following BN GBM), but did not develop glomerular deposits of IgG or nephritis. Animals given 2 mg/kg SD GBM in CFA developed greater concentrations of anti-GBM antibody by 6 weeks (122 +/- 20%) together with linear deposits of IgG on glomerular and tubular basement membranes (TBM), albuminuria (mean 7 mg/24 h), and variable focal segmental necrotising glomerulonephritis with mild interstitial nephritis. The same dose of BN GBM in CFA produced similar concentrations of circulating antibody (144 +/- 26%), with linear deposits of IgG on GBM but rarely TBM, little albuminuria, and variable mild focal glomerulonephritis. Other strains injected with SD GBM in CFA showed a variable circulating anti-GBM antibody response, which was similar to that of BN rats in PVG and DA rats but lower in LEW and WAG rats. Linear deposits of IgG on the GBM were detected in a proportion of PVG and DA rats, but not in LEW or WAG rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Proximal tubular dysfunction in primary Sjögren's syndrome: a clinicopathological study of 2 cases

Tubulointerstitial nephritis is the most common renal complication in primary Sj?gren's syndrome (SS). It is usually associated with symptoms of distal tubular dysfunction, type I (distal) renal tubular acidosis (RTA) and nephrogenic diabetes insipidus. Proximal tubular abnormalities are considered to be less frequent, and Fanconi's syndrome has been only exceptionally reported in patients with SS. We describe 2 patients with primary SS, characterized by xerostomia, dry eyes, extensive lymphocytic infiltrate on salivary gland biopsy, positive tests for anti-SSA/SSB antibodies and/or antinuclear antibodies, who presented in renal failure with proteinuria, microscopic hematuria and type I RTA. Further studies revealed proximal tubular dysfunction, including renal glucosuria, generalized aminoaciduria, phosphaturia, uricosuria, together with proximal (type II) RTA in 1 case. Neither of these patients had Bence Jones proteinuria or monoclonal gammopathy. Kidney biopsy showed focal proximal tubulitis, associated with proximal tubular cell atrophy and dedifferentiation, and diffuse interstitial nephritis with fibrosis. No significant glomerular or peritubular deposits of immunoglobulin light or heavy chain were observed. These findings demonstrate that diffuse, distal and proximal, tubular dysfunction may occur in patients with SS and interstitial nephritis. Lymphocytic infiltration of proximal tubular cells is probably involved in the pathogenesis of Fanconi's syndrome in SS. However, the mechanisms involved in the alteration of sodium-dependent apical transports remain to be elucidated.     

Significance of mast cell renal infiltration in patients with anti-GBM nephritis

To investigate the role of mast cells (MCs) renal infiltration in the progression of human anti-GBM nephritis, 38 patients diagnosed with anti-GBM nephritis were enrolled. Renal biopsies were performed. Immunohistochemistry was conducted to detect MCs in renal tissues. Patients were divided into group 1 (MCs?<50?mm^?2, n?=?18) and group 2 (MCs?≥50?mm^?2, n?=?20) according to the infiltrating renal MC count. The clinical–pathological indices were compared. And, correlation between MCs and the clinical–pathological indices was analyzed. Patients of group 2 had more severe renal dysfunctions, expressed as higher levels of serum creatinine (SCr 8.95?±?3.66 vs. 4.75?±?2.73?mg/dL, p?<?0.001), urine retinol-binding protein (RBP 29.8?±?13.9 vs. 15.7?±?11.5?mg/dL, p?=?0.005), and lower urinary osmotic pressure. Pathologically, patients of group 2 had a higher percentage of fibrous/fibrocellular crescents (66.7?±?21.9 vs. 47.0?±?33.6%, p?=?0.037) but a lower percentage of cellular crescents. More CD8 (268?mm^?2 vs. 180?mm^?2, p?=?0.045) and CD68 (268?mm^?2 vs. 180?mm^?2, p?=?0.045) positive cells infiltrating the interstitium were observed in group 2. Furthermore, renal MCs correlated significantly with the total number of crescents and the tubular interstitial CD8 and CD68 positive cells. And, the number of MCs was associated with the histological types. The renal function was significantly different between the two groups at presentation. However, at 3 and 6 month follow-up, the patient outcome was associated with the histological types. Our study showed that MC infiltrations were associated with chronic lesions in anti-GBM nephritis and may be involved in the loss of renal function with pathological changes.     

Tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis

We report a patient who suffered from cutaneous vasculitis with renal involvement comprising tubulointerstitial (TI) nephritis and relatively mild glomerulitis. Renal biopsy revealed immune deposits both in mesangium and along tubular basement membrane (TBM), suggesting that immune complexes played a significant role in the development of renal damage. Although it is well known that vasculitic syndromes commonly affect glomeruli, this report is the first to demonstrate tubulointerstitial immune complex nephritis in a patient with cutaneous vasculitis.     

Predominant tubulointerstitial nephritis in a patient with systemic lupus nephritis

In most cases of systemic lupus erythematosus (SLE), glomerular lesions are the main renal complication. Although tubulointerstitial lesions are often associated with severe glomerular lesions, predominant or isolated tubulointerstitial injury in the presence of minimal glomerular abnormalities with SLE, so-called predominant tubulointerstitial lupus nephritis, is rare. Only ten cases are reported in the English literature. Herein, we describe the case of a 64-year-old man with SLE who presented with acute renal deterioration attributable to acute tubulointerstitial nephritis. Renal biopsy showed diffuse infiltration of inflammatory mononuclear cells in the interstitium and tubulitis without significant glomerular lesions. Immunofluorescence study revealed positive staining for IgG, C3, and C1q along the renal tubular basement membrane (TBM). Electron microscopy also showed electron-dense deposits in the TBM. Other causes of tubulointerstitial injury, such as drug use and infection, were ruled out. Taking these findings together with the presence of antitubular basement membrane antibody, predominant tubulointerstitial lupus nephritis was diagnosed. Treatment with oral corticosteroids for 6 weeks improved renal function. Even after tapering of the corticosteroid, renal function and serological markers of SLE activity have remained stable in this patient for more than 12 months.     

Effect of antitubular basement membrane and brush border antibodies on p-aminohippurate transport in kidney

The effect of antiproximal tubule basement membrane (TBM) and brush border (BB) antibodies on p-aminohippurate (PAH) transport was evaluated in a rat model of immunologically mediated interstitial nephritis. Immunized rats developed anti-TBM antibody titers ranging from 1 to 3,072 with continuous linear IgG and interrupted C3 deposits in the TBM. Circulating anti-BB antibodies were detected in half of the immunized rats in titers ranging from 1 to 128. Heavy IgG deposition was present in the BB when circulating anti-BB antibody titers exceeded eight and proteinuria was present. When anti-TBM antibody titers were 1,024 or greater the slice-to-medium PAH concentration ratio (S/M) was significantly reduced (p less than 0.001). Combined immunofluorescent microscopy and section freeze-dry autoradiography revealed normal cellular distribution of PAH-3H in all proximal tubules except in rat microscopic foci of interstitial nephritis in which concentrative transport was absent. However, luminal secretion of PAH-3H was strikingly reduced in tubules with heavy IgG BB deposits. 3-hour PAH secretion in vivo fell significantly in rats with circulating and tissue anti-BB antibodies. Antibody inhibition of PAH transport appeared to be independent of morphologic damage. Summary: Anti-TBM antibodies were associated with decreased slice uptake of PAH-3H while anti-BB antibodies were associated with decreased luminal PAH secretion in vitro and in vivo.     

Childhood membranous nephropathy, circulating antibodies to the 58-kD TIN antigen, and anti-tubular basement membrane nephritis: an 11-year follow-up

Childhood membranous nephropathy (MNP) with anti-tubular basement membrane (anti-TBM) nephritis is a rare disorder that may have extrarenal manifestations. This article describes a new case to be added to the 10 previously reported. A renal biopsy specimen from a 1-year-old white boy with nephrotic syndrome, microhematuria, and hypertension showed MNP (granular global IgG, IgA and C3, and segmental IgM and C1q) associated with hypercellularity and granular deposits of IgM and C1q in the mesangium, arteriolar IgA, and linear TBM IgG, IgA, and C3. A biopsy at age 4 years showed MNP (IgG and C3) and linear IgG and C3 along the TBM. Six months later, temporary glucosuria suggested a mild tubular dysfunction. Biopsy at age 8 years showed sclerosing MNP (IgG and C3), linear TBM IgG and C3, and chronic active tubulointerstitial nephritis (TIN). Indirect immunofluorescence showed circulating anti-TBM antibodies, and the enzyme-linked immunosorbent assay (ELISA) approach verified strong reactivity with the 58-kd TIN antigen. Despite trials with steroids, chlorambucil, azathioprine, and cyclosporine, end-stage renal disease developed by the age of 9 years. At age 10 years, the patient received a cadaveric kidney transplant. With the patient now aged 12 years, the graft is still functioning well, without any clinical evidence of disease recurrence. Neurological, ocular, and abdominal symptoms, including nonbacterial diarrhea, were observed during the follow-up period. The pathophysiology of these extrarenal symptoms remains unclear. Serotyping and genotyping of HLA antigens (A2, A10, B12, B41, DR5 [1101, 1103-4, 1106 or 1108-1113], DR6 [1303, 1312, or 1413], DRB3 [*0101 and 0201-2 or 0301], DQA1 [*0501 homozygous], and DQB1 [*0301 homozygous]) did not indicate any HLA association similar to those described previously in childhood MNP with anti-TBM nephritis (HLA-B7 in four patients, HLA-DR8 in two patients). The presented case is the fifth in the literature that displays reactivity with the 58-kd TIN antigen, and for which data on HLA antigens are reported.     

Detection of nephritogenic antigen from the Lewis rat renal tubular basement membrane

Immunopathogenicity of trypsin-solubilized or non-solubilized renal tubular basement membrane (TBM) of the Lewis (LEW) rat was investigated. Autoimmune tubulointerstitial nephritis (TIN) was induced in BALB/c mice by immunization with trypsin-solubilized LEW rat TBM, while immunization with non-solubilized TBM did not produce the disease. Based on this preliminary experiment we studied the characterization of immunogenic and nephritogenic TBM antigen of the LEW rat. TIN was characterized by severe mononuclear cell infiltrates with multi-nucleated giant cells in the interstitium, tubular destruction and intensive IgG and C3 deposits along the TBM. Anti-TBM antisera and eluate from the nephritic mouse kidneys reacted with the TBM of normal LEW rat kidney by immunofluorescence. LEW rat TBM was also detected immunofluorescently by using antisera from BALB/c mice immunized with autologous trypsin-solubilized TBM. A competitive inhibition test revealed a higher titer of anti-TBM antibody in the eluate than in the adsorption-treated antisera per microgram IgG. Immunoblotting showed one reactive band with a molecular weight of 45,000 daltons, and the blotting patterns in tryptic TBM of the Brown Norway (BN) and LEW rats appeared similar. Amino acid analysis of nephritogenic LEW rat tryptic TBM showed that it contained no hydroxyproline and hydroxylysine, suggesting that this TBM preparation was not collagenous. These findings suggest that tryptic digestion contributes to the release of nephritogenic antigen from the LEW rat TBM and that this antigen system might participate in the immune system involved in the anti-TBM associated TIN that is well known to be induced by non-digested TBM of TBM antigen positive animals.     

High nephritogenicity of monoclonal antibodies belonging to IgG2a and IgG2b subclasses in rat anti-GBM nephritis

BACKGROUND: To examine a subclass-effect relationship and a dose-effect relationship of autoantibodies in the rat antiglomerular basement membrane (GBM) antibody-induced glomerulonephritis (anti-GBM nephritis) model, we injected homologous monoclonal antibodies against the NC1 domains of rat type IV collagen into inbred Wistar-Kyoto (WKY) rats. METHODS: Eight different autoantibodies from each of the IgG1, IgG2a, and IgG2b subclasses were established and administered to groups of four WKY rats at a dose of 300 microg/rat. To examine the dose-effect relationship, we administered 0 to 300 microg/rat of autoantibodies from each subclass to rats. RESULTS: All IgG1 antibodies induced mild nephritis, whereas the IgG2a and IgG2b antibodies induced moderate to severe nephritis. Some IgG2a and IgG2b antibodies induced pulmonary hemorrhage as well. These antibodies were reactive with alpha3(IV)NC1, alpha4(IV)NC1, or alpha5(IV)NC1. The minimum dose of antibody required to induce nephritis was 30 microg/rat for IgG1, 3 microg/rat for IgG2a, and 1 microg/rat for IgG2b. At doses of 30 microg/rat or less, antibody deposition was generally restricted to the GBM. At doses of 100 microg/rat or greater, antibody deposition extended to both the GBM and tubular basement membrane (TBM). Pulmonary hemorrhage was observed only when a large amount of pulmonary hemorrhagic antibody was administered. CONCLUSION: The severity of nephritis was dependent on both subclass and dose of autoantibodies. It becomes clear that pulmonary hemorrhage in anti-GBM nephritis is induced by autoantibodies.     

Sodium-valproate-induced interstitial nephritis

A 5-year-old Chinese girl had had absence seizures and received sodium valproate (VPA) treatment which provided good control. Six months later, she developed interstitial nephritis with proteinuria and microhematuria. Renal biopsy revealed interstitial nephritis with granular deposition of immunoglobulin G (IgG) and C3 in the renal tubular basement membrane (TBM). Ultrastructurally, dilated smooth endoreticular cisternae with mitochondrial degeneration in the tubular cells and scattered electron-dense deposits within the TBM were also noted. Serum circulating immune complexes were detectable, ACH50 and properdin factor B increased. Mononuclear cells (MNC) from the patient after in vitro incubation with VPA (100 micrograms/ml) induced interleukin-2 (IL-2) production and lymphoproliferative response. However, there was no response in controls. The serum VPA level ranged from 84 to 92 micrograms/ml. After VPA was stopped, the microhematuria and proteinuria disappeared. These observations indicate that VPA-induced interstitial nephritis represents a sequence of interrelationships among multiple immunologic factors.     

应用抗肾小球基底膜抗体的中和性单克隆抗体治疗抗肾小球基底膜肾炎大鼠的实验研究

目的 应用抗肾小球基底膜（GBM）抗体的中和性单克隆抗体注射抗GBM肾炎大鼠,观察各种生化指标及肾脏病理学的变化。 方法 将Wistar大鼠随机分为5组,每组9只：(1)肾炎模型组：经尾静脉注入人抗GBM抗体;(2)正常对照Ⅰ组:经尾静脉注入非抗体性的健康人lgG;(3)对照Ⅱ组：经尾静脉注入抗GBM抗体的中和性单克隆抗体;(4)干预Ⅰ组：经尾静脉注入人抗GBM抗体,第7天后再经尾静脉注入抗GBM抗体的中和性单克隆抗体(1.5 ml/100 g);(5)干预Ⅱ组：经尾静脉注入人抗GBM抗体,第14天后再经尾静脉注入抗GBM抗体的中和性单克隆抗体。分别在实验后第7、14、21天观察大鼠24 h尿蛋白量、BUN、Scr和肾组织病理学的变化。 结果 第21天干预Ⅰ组尿蛋白量为（16.62±5.53） g/d、BUN为（11.53±2.26） mmol/L、Scr为（102.46±16.86） μmol/L,均显著低于肾炎模型组（P < 0.05）;干预Ⅱ组较肾炎模型组也有所降低,但差异无统计学意义（P > 0.05）。干预Ⅰ组和干预Ⅱ组肾脏细胞增生、新月体的形成及免疫复合物的沉积均少于肾炎模型组,但干预I组更为明显。对照Ⅰ组和对照Ⅱ组之间无明显变化。 结论 早期应用抗GBM抗体的中和性单克隆抗体能够有效改善抗GBM肾炎大鼠的肾脏病变。     

Anti-glomerular basement membrane (anti-GBM) disease accompanied by vasculitis that was not positive for antineutrophil cytoplasmic antibodies to myeloperoxidase and proteinase 3: a report of two cases and the incidence of anti-GBM disease at one institution

Background

Anti-glomerular basement membrane (anti-GBM) disease is thought to be distinct from vasculitis. In contrast, there have been several papers suggesting the presence of angiitis in cases that were positive for anti-GBM antibody (Ab), as well as for either myeloperoxidase (MPO)- or proteinase 3 (PR3)-anti-neutrophil cytoplasmic antibody (ANCA) (Group I). We experienced four patients who had anti-GBM Abs, but not MPO- and PR3-ANCA (Group II), and two of these patients were found to have vasculitis. Therefore, we performed an in-depth study on these two patients.

Methods

The patients with anti-GBM disease were isolated from 578 cases whose renal tissues were examined, and they were categorized into two groups. We have already published the data about Group I. We then proceeded to study two vasculitic patients in Group II clinically, pathologically, and serologically. The anti-GBM Ab and ANCA levels were detected by enzyme-linked immunosorbent assays. Renal specimens were studied by routine staining as well as immunohistochemical investigations of CD31 and type IV collagen.

Results

The total number of patients with anti-GBM disease was 7 (7/578?=?1.2%), with 3 patients belonging to Group I and 4 patients belonging to Group II. Two patients in Group II were diagnosed to have vasculitis, but the remaining 2 patients did not. One vasculitic patient was complicated by pulmonary hemorrhage, while the other vasculitic patient displayed peripheral neuropathy as well as a small cavity lesion in the lung. The latter patient was found to be positive for perinuclear (p)-ANCA, but not for any other ANCA subsets. The renal pathology in the two vasculitic patients showed crescentic glomerulonephritis (CSGN) and immunoglobulin (Ig) G linear deposits along the glomerular capillary loops. The former patient showed fibrinoid angiitis in an afferent arteriole as well as peritubular capillaritis. The latter patient demonstrated peritubular capillaritis. These peritubular capillaritides were diagnosed by the loss of CD31 and type IV collagen staining, the blurred appearance of peritubular capillary walls by periodic acid-Schiff staining, and the pericapillary infiltration of inflammatory cells.

Conclusion

The incidence of anti-GBM disease was very low, and our patients were categorized into two groups (Groups I and II) based on whether or not they were positive for MPO- or PR3-ANCA. Two patients in Group II were found to have vasculitis. According to our results, we concluded that the anti-GBM disease of Group II could also be associated with vasculitis.     

Linear C3 deposits on the tubular basement membrane in renal allograft biopsies

Linear and granular tubular basement membrane (TBM) deposits of C3 occur in renal allograft biopsies, but their significance is unknown. We retrospectively analyzed the predictive importance of C3 deposits in 88 biopsied transplant patients with allograft dysfunction. All patients were followed for greater than or equal to 2 years from biopsy. Patients were divided into three groups: group I: no C3 deposits, 47 patients; group II: granular deposits of C3, 28 patients; and group III: linear TBM deposits, 13 patients. The incidence of acute and chronic rejection was not different. In group III, 12 grafts were lost by 5 years (92%), and the remaining patient has chronic rejection. Group III survival was significantly less than groups I and II (Kaplan-Meier curves), P = 0.02, but graft survival in groups I and II were similar. There was no association of anti-TBM antibody deposits with C3, and the mechanism of deposition is unknown. We conclude that the presence of linear C3 deposits along the TBM in the setting of allograft dysfunction is associated with decreased allograft survival.     

Kidney transplantation in Alport's syndrome: long-term outcome and allograft anti-GBM nephritis.

Anti-glomerular basement membrane (anti-GBM) nephritis occurring in kidneys transplanted in patients with Alport's syndrome (AS) has been reported repeatedly. Therefore, we studied graft survival and course of renal function in all 30 AS patients grafted at Hannover Medical School and compared them with non-diabetic, age and sex matched patients, transplanted on the date closest to the transplantation of the AS patient. Serum creatinine, proteinuria, urinary sediment and anti-GBM antibodies were examined in all AS patients with functioning grafts. Cases of patient or graft loss in the AS group were analyzed retrospectively. One- and five-year patient survival was 100 and 91% in AS and 89 and 78% in controls (p > 0.05, respectively). One- and five-year first graft survival was 79 and 66% in both groups. Graft histology was available in 34 biopsies obtained from 21 kidneys in 15 AS patients. Anti-GBM nephritis was not detected in any of the biopsies. No graft was lost due to anti-GBM nephritis. Anti-GBM antibodies were detectable temporarily only in one AS patient. He also had linear IgG staining in his graft GBM, but no other signs of anti-GBM nephritis. We conclude that patient survival and graft survival in AS patients following kidney transplantation is not different from non-AS patients. Allograft anti-GBM nephritis is a rare complication in patients with Alport's syndrome.