Excellent long-term graft survival in low risk, primary renal allografts treated with prednisolone-avoidance immunosuppression.

Primary avoidance of oral corticosteroids for renal transplant recipients is uncommon. The South Australian renal transplant service used a double therapy (DT) regimen of cyclosporin and azathioprine from August 1986 to July 1996 for low risk (first graft, PRA < 50%) allografts. Oral corticosteroid, prednisolone (P), was reserved for severe rejection or two mild rejection episodes, but could be later withdrawn at the physician's discretion. This regimen is associated with more early acute rejection (Russ et al., Clin Transplant 1990: 4: 26). We have now analysed long-term patient survival (PS) and graft survival (GS) for this group. Of 448 transplants in South Australia between August 1986 and July 1996, 295 commenced DT regimen. Ninety-four (31.8%) never received P at any stage post-transplantation (group 1), 96 (32.5%) were placed on P and later weaned (group 2), and 97 (33%) remained on long-term P (group 3). Technical losses, eight (2.7%), within 30 d of transplantation, were excluded from sub-group analysis. PS for the total DT cohort at 1, 5 and 9 yr post-transplantation was 97, 88 and 74%, respectively. GS over the same time period was 88, 75 and 55%, respectively. There was no statistically significant difference in survival compared to other 'low risk' grafts in the rest of Australia during the same time period. Mean serum creatinine concentration (CrC) for the DT group at 3 and 6 months and 1, 3, 5 and 10 yr was not significantly different to the rest of the Australian 'low risk' grafts. In the DT cohort, there were 334 acute rejections ( < 90 d) in 206 patients (70%), but only 42 (12.5%) required anti-lymphocyte antibody therapy (OKT3 or ATG) for rejection. PS at 9 yr was not statistically significantly different between groups 1 and 2, but both groups survived better than group 3 (p < 0.0043). GS for group 1 at 1, 5 and 9 yr post-transplantation was 90, 81 and 73%, respectively; for group 2, 98, 87 and 66%, respectively; and for group 3, 84, 63 and 29%, respectively. Statistical significance was reached in group 1 versus 3 (p < 0.001) and group 2 versus 3 (p < 0.001). In summary, a DT regimen in low risk, first renal allografts gives excellent long-term patient and GS and minimises long-term P, despite a high rate of early acute rejection.

Clozapine-induced acute interstitial nephritis.

Drug hypersensitivity reactions commonly cause acute interstitial nephritis (AIN). Clozapine, a new antipsychotic, can cause fatal bone-marrow toxicity. We report clozapine-induced AIN as another serious adverse drug reaction.

Infiltration of the kidney by alpha beta and gamma delta T cells: effect on progression in IgA nephropathy.

We have studied renal biopsies from three groups of patients to determine if alpha beta T cells or gamma delta T cells are present, and whether their presence is correlated with disease progression in IgA nephropathy (IgAN). Group one comprised thin basement membrane disease biopsies (non-immunological control, N = 7); group two were patients with IgAN and stable renal function one year following biopsy (stable, N = 7); and group three were IgAN patients with rapidly declining renal function after one year (progressive, N = 7). Immunohistochemical staining using monoclonal antibodies (CD3, TcR beta, TcR delta) and molecular studies utilizing polymerase chain reaction amplification of cDNA transcribed from biopsy RNA, with primers specific for either the alpha beta TcR or gamma delta TcR, were undertaken. On immunohistochemistry a significant increase in CD3 + cells in progressive biopsies was seen (vs. control P = 0.002, vs. stable P = 0.002). The progressive biopsies infiltrate consisted of both alpha beta TcR (vs. control P = 0.001, vs. stable P = 0.003) and gamma delta TcR cells (vs. control P = 0.01). The RNA study demonstrated an increase in TcR C alpha transcription in the progressive (vs. control P = 0.003) biopsies. Increased TcR C delta transcription was seen in the progressive group (vs. control P = 0.01, vs. stable P = 0.02). We confirm that the presence of lymphocytes in IgAN biopsies predicts progressive disease. While alpha beta T cells are found in both stable and progressive disease, the presence of gamma delta T cells is only associated with progressive IgAN.

Recurrent mesangial IgA nephritis following renal transplantation.

Recurrence of mesangial IgA deposits in renal allografts of patients whose original disease was primary IgA nephropathy (IgAN) has been studied. Forty-six patients with primary IgAN received 51 renal allografts and have been followed for 3-183 months. A prospective study of 11 patients (11 biopsies) and a retrospective analysis of 17 patients (16 biopsies; 2 nephrectomy specimens) have been combined. Seventeen of the 29 allografts had recurrent mesangial IgA deposits and of these three patients have negative urinalysis, normal glomeruli by light microscopy, and stable renal function; six patients have microhaematuria, mesangial proliferative nephritis, but at present stable renal function; and five have mesangial proliferative glomerulonephritis with microhaematuria, heavy proteinuria, hypertension, and progressive allograft failure secondary to IgA disease alone, and one of these is now back on dialysis. Three other grafts with recurrent deposits are failing because of transplant glomerulopathy or rejection. The only predictor identified for recurrence of mesangial IgA deposits was length of time post-transplantation, with allograft tissue being studied at 45.9 +/- 10.0 versus 15.3 +/- 4.8 months (P = 0.008) post-transplantation in patients with and without recurrent deposits respectively. Cyclosporin A did not prevent recurrence. By virtue of a longer follow-up of patients post-transplantation than all other reported series, these results suggest that with increasing time post-transplantation recurrence of mesangial IgA disease will become increasingly important as a cause of progressive allograft dysfunction and failure unless effective treatment is found for the primary disease.

Renal failure due to mesangiocapillary glomerulonephritis in pregnancy: use of plasma exchange therapy.

A 20-year-old female became pregnant 4 years after diagnosis of type I mesangiocapillary glomerulonephritis. Despite normal serum creatinine at conception renal function deteriorated during pregnancy. The use of plasmapheresis and albumin substitution as well as antihypertensive therapy enabled the continuation of the pregnancy from 27 weeks' gestation until a healthy infant could be delivered at 33 weeks. However, an abrupt decline in function at delivery did not reverse and the patient remains dialysis dependent. We conclude that plasma exchange therapy with albumin substitution may be of benefit in women with mesangiocapillary glomerulonephritis when renal function has deteriorated in pregnancy. Stabilization of renal function can allow continuation of the pregnancy until greater fetal maturity makes the delivery of a healthy infant more likely. Although plasma exchange is an experimental therapy, in our hands it appears safe for the fetus and maternal complications were limited to minor vascular access problems. The best prognostic marker in this case was the severity of the most recent renal biopsy rather than the level of renal function or hypertension at the start of pregnancy. This contrasts with most reported cases of pregnancy and primary glomerular disease where irreversible deterioration of renal function was uncommon when renal function at the start of pregnancy was only mildly impaired and hypertension well controlled.

Kit preparation of technetium-99m-mercaptoacetyltriglycine: analysis, biodistribution and comparison with technetium-99m-DTPA in patients with impaired renal function.

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) was prepared by a frozen solution method, enabling the preparation of kits yielding a product substantially free of lipophilic impurities (96% 99mTc-MAG3). However, biliary activity was not completely eliminated as HPLC-purified 99mTc-MAG3 was also excreted by that route. Sequential 99mTc-DTPA and 99mTc-MAG3 renal scans were performed in 15 patients with renal dysfunction, including renal transplant recipients. In all cases, the 99mTc-MAG3 kit preparation provided superior images to 99mTc-DTPA at all levels of renal function due to a higher target-to-background ratio and a plasma clearance twice as fast as 99mTc-DTPA. Interpretation of delayed 99mTc-MAG3 images, however, was complicated by biliary excretion which will limit quantitative estimates of renal clearance. A 99mTc-MAG3 kit is likely to be of value in renal transplant assessment and in cases of significant renal impairment but would not appear to offer major advantages over 99mTc-DTPA in routine renal imaging.

Induction, characterization, and cell transfer of autoimmune tubulointerstitial nephritis.

Autoimmune tubulointerstitial nephritis (TIN) was induced in Lewis (LEW) rats by immunization with homologous Brown-Norway (BN) rat renal basement membrane (RBM), complete Freund's adjuvant and Bordetella pertussis vaccine. The BN strain has a tubular basement membrane (TBM) antigen (Ag+) detectable by immunofluorescence which is lacking in unmodified LEW rat TBM. Development of TIN in LEW rats correlated with TBM Ag+ immunogens from homologous and heterologous RBM preparations. By day 14 after immunization TIN developed characterized by elevated serum creatinine levels and by tubular destruction with focal, circumscribed lesions containing epithelioid cells, giant cells and mononuclear cell infiltrates. Approximately 60% of the mononuclear cells bore T cell antigens with most cells expressing Ia markers. Immunofluorescence and elution studies revealed no selective IgG fixation to TBM at day 14 despite high titers of circulating alloantibody reactive with the immunizing TBM. Intravenous transfer of LNC and/or splenic cells (3.5 to 7 X 10(8)) to naive LEW rats resulted in less severe but histologically identical TIN in seven days with T cell subpopulations similar to those seen in the active model. This model strongly suggests an initiating role for cell-mediated immunity in TIN in the rat and may provide a parallel to human TIN.

Inhibition of the neutrophilic infiltrate of experimental tubulointerstitial nephritis in the Brown-Norway rat by decomplementation.

Anti-tubular basement membrane (TBM) antibody-associated tubulointerstitial nephritis (TIN) in Brown-Norway rats is induced by immunization with bovine TBM antigens and adjuvants. The lesion is characterized by linear deposition of IgG and C3 along the TBM with sequential neutrophil (Days 8-9)- and mononuclear (Day 10 and after)-dominated inflammatory infiltrates. To study the complement dependence of the infiltrative process, immunized rats were decomplemented with cobra venom factor (CVF). The CVF treatment did not affect the production or renal deposition of anti-TBM antibodies. CVF markedly reduced the neutrophilic inflammatory infiltrate. In rats immunized with suboptimal doses of soluble bovine TBM antigens to produce a mild lesion, decomplementation also decreased the mononuclear inflammatory infiltrates on Days 10-13. In rats immunized optimally with particulate TBM to induce maximally severe TIN, decomplementation did not affect the mild mononuclear cell infiltrate on Days 8 and 9 but did somewhat reduce the subsequent mononuclear infiltrate on Days 10 and 12. These results demonstrate that the anti-TBM antibody- and C3-associated neutrophilic inflammatory infiltrate is largely complement dependent. The early mononuclear cell infiltrate that was unmodified by CVF treatment may be dependent on complement-independent humoral events or related to cell-mediated immune events. A portion of the later mononuclear inflammatory infiltrate could be dependent on the preceding neutrophilic inflammatory phase.

Transfer of tubulointerstitial nephritis in the Brown Norway rat with anti-tubular basement membrane antibody: quantitation and kinetics of binding and effect of decomplementation.

Lewis (LEW) rats immunized with Brown Norway (BN) rat renal basement membrane (RBM) and adjuvants produce high titer circulating anti-BN tubular basement membrane (TBM) antibodies, in addition to developing an autoimmune cell-mediated form of nodular tubulointerstitial nephritis (TIN). This immune LEW serum, which reacted with BN TBM but not LEW TBM by immunofluorescence, was capable of passively transferring TIN as early as 24 hr after administration of volumes as low as 3 ml i.v. to normal BN recipients, producing focal lesions histologically and immunopathologically similar but less extensive than those studied previously in this strain after active immunization with heterologous RBM. In contrast, a total of 45 ml of serum (in multiple doses) from BN rats immunized with bovine RBM and adjuvants produced only one small lesion of TIN in a recipient BN rat. This difference in serum transferability of anti-TBM-associated TIN appears to relate to quantitative differences in anti-particulate and soluble (collagenase-extracted) BN RBM antigen reactivity measured by radioimmunoassay. Paired-label quantitative studies of passively transferred LEW anti-BN RBM IgG demonstrated a slow accumulation of renal-bound antibody over 6 days, and corresponded with kidney elution and immunofluorescence studies after transfer of immune LEW sera to normal BN rats. Approximately 167 micrograms of kidney-fixing antibody per gram of kidney were calculated to be required for the development of the earliest cellular infiltration. C3 depletion with cobra venom factor greatly diminished the development of destructive TIN lesions associated with multinucleate giant cells after passive transfer of LEW anti-BN RBM antibody to BN rats. This study, using immune LEW sera containing high levels of anti-BN RBM antibody, has defined and quantitated a role for anti-TBM antibody and complement in the initiation of TIN in BN rats.

Tubulointerstitial nephritis induced in the brown Norway rat with chaotropically solubilized bovine tubular basement membrane: the model and the humoral and cellular responses.

Doses of as little as 50 micrograms of a soluble chaotropic extract of bovine tubular basement membrane (Bov-KBr-TBM) with adjuvants induced anti-TBM antibodies and tubulointerstitial nephritis (TIN) in Brown Norway (BN) rats. The lesion was shown by renal histology, by deposition of IgG and C3 along TBM, and in terms of the humoral and cellular immune responses to compare to that produced by the standard immunization (particulate bovine TBM) for this model of TIN in BN rats. More than half of the mononuclear cells in kidneys of BN rats with TIN bore various T-cell antigens (monoclonal antibodies W3-13, W3-25, and OX-8), and most of the infiltrating cells were positive for Ia (monoclonal antibody OX-6) by indirect immunofluorescence. Purified suspensions of these mononuclear infiltrates were prepared by using Ficoll-Hypaque gradients and the fluorescence-activated cell sorter (FACS) to eliminate renal tubular epithelial cells. The purified mononuclear cells, cultured for 5 days, incorporated thymidine in response to concanavalin A (Con A), Mycobacterium tuberculosis purified protein derivative, and Bov-KBr-TBM but not in response to a variety of autologous renal antigens. After culture for 5 days in Bov-KBr-TBM and Con A supernatant, lymph node cells (LNC) from Bov-KBr-TBM-immunized BN rats passively transferred TIN to naive BN rats. Although no cells reactive with autologous renal antigens were detected in the renal infiltrates, the transfer of disease with propagated LNC suggests that elements of the cellular immune system, in addition to anti-TBM antibody, contribute to the generation of this BN-TIN.