Urinary retinol binding protein in Indo-Asian patients with idiopathic interstitial nephritis.

BACKGROUND: Idiopathic interstitial nephritis (IIN) is common in the UK Indo-Asian population. Lack of systemic involvement and unremarkable urinalysis on stick testing suggest that it may underlie some cases of end-stage renal failure of undetermined cause. If IIN is diagnosed early, prompt initiation of treatment can improve long-term outcome. AIMS: To investigate whether urinary retinol binding protein (RBP) is elevated more commonly than urinary albumin in IIN, and might be useful in the early detection of renal disease in Indo-Asian patients. DESIGN: Preliminary observational study METHODS: We measured urinary RBP and urinary albumin in 19 Indo-Asian patients in whom a renal biopsy had shown IIN, 10 of whom had already been treated with corticosteroids at the time of specimen collection. A further 28 Indo-Asian patients with glomerular disease, and six with normal light-microscopic renal biopsy, were assessed in parallel. RESULTS: Urinary RBP/creatinine ratio (RCR) was elevated in all 19 cases of IIN, compared to 12/19 in whom the albumin/creatinine ratio (ACR) was elevated. Elevated urinary RBP was thus significantly more common than albuminuria in this group (p<0.01). Twelve of the 19 cases also satisfied the criteria for tubular proteinuria. RCR was elevated to >30 times the upper limit of normal in 7/9 who had not previously received corticosteroids, of whom four had normal ACR; none had ACR >5 times the upper limit of normal. DISCUSSION: These data suggest that measurement of urinary RBP should be explored as an adjunct to albuminuria, if screening for renal disease in the Indo-Asian population is contemplated.

Donor selection for xenotransplantation: detection of Galalpha1-3Gal on different porcine organs.

The expression of the major porcine xenoantigens (Galalpha1-3Gal) in different tissues varies between species. The selection of suitable donors and the interpretation of studies which attempt to prevent hyperacute rejection are dependent on donor expression of Galalpha1-3Gal. Screening of large number of animals to find potential Galalpha1-3Gal negative donors requires a robust, tissue-based and practical method of assessing Galalpha1-3Gal expression. In this study, we have assessed the expression of Galalpha1-3Gal in a variety of pig organs using anti Galalpha1-3Gal antibody. Biopsies of heart, kidney, ear and tail were obtained from 20 outbred pigs. Biopsies were fixed in formalin and stained with a human anti Galalpha1-3Gal antibody obtained from pooled human AB serum passed down a Galalpha1-3Gal immunoadsorbent column. Tissue from all 4 organs from all 20 pigs expressed Galalpha13Gal. This study shows that detection of Galalpha1-3Gal on an ear or tail biopsy is a simple but very reliable method for assessing Galalpha1-3Gal expression on the heart and kidney and facilitates donor selection for xenotransplantation.

Xenografts--future prospects for clinical transplantation.

This paper outlines the basic problems that still need to be overcome before xenografting becomes a reality. It presents evidence that if the first of these problems (preformed or natural antibody to pig) can be overcome then pig kidneys will: (a) not hyperacutely reject from a human; and (b) will not, under currently used immunosuppression, induce massive new primary or secondary responses. It also makes brief justification of the use of the pig as the donor of choice and outlines what essential animal work we feel necessary before an actual pig-to-human transplant is contemplated.

Successful transplantation of kidneys bearing previously mismatched HLA A and B locus antigens.

Transplantation of kidneys bearing HLA antigens to which recipients have previously been exposed is generally avoided, and such prudence is a well-documented means of preventing early graft loss. Prior exposure and subsequent reactions can, however, take a wide variety of forms, and blanket avoidance may prevent many deserving patients from being transplanted. In our region, operating through a single tissue-typing laboratory, we follow a consistent policy of allowing retransplantation with kidneys bearing previous mismatches, provided no relevant antibody response has been detected. Twenty-one of 34 such transplants remain functioning at time periods ranging from 7 months to 7 years. Four were lost due to rejection within the 1st month, and the remaining 9 functioned for periods ranging from 2 months to 8 years. Three were lost for reasons other than rejection. Our antibody screening policy and our criteria for a negative crossmatch results in the exclusion of two-thirds of all repeat mismatch transplantations. The results indicate that in the remaining third, transplantation can be performed across a repeat mismatch with excellent long-term results, provided our defined crossmatch policy is adhered to strictly.

Association of membranous nephropathy with T-cell receptor constant beta chain and immunoglobulin heavy chain switch region polymorphisms.

We have investigated T-cell antigen receptor constant beta chain genes (Tcr C beta) and immunoglobulin (Ig) heavy chain switch region genes of HLA-DR-typed patients with membranous nephropathy (MN) employing DNA restriction fragment length polymorphism (RFLP) analysis. When a Tcr C beta probe in conjunction with the restriction endonuclease Bgl II was used, a significant increase in the frequency of a 10.0; 9.2 kb heterozygous RFLP phenotype was found in MN (75.0% versus 42.1% in controls; P = 0.002). When Sst I-restricted DNA from MN patients was hybridized with a DNA probe homologous to the switch region flanking the Ig C mu heavy chain gene (S mu), there was a significant decrease in the frequency of the 2.1; 2.6 kb heterozygous RFLP phenotype in MN (24.0% versus 54.6% in controls; P = 0.004). These results suggest that Tcr beta and Ig heavy chain loci, as well as HLA antigens, may be important in the pathogenesis of MN.

Histopathological changes in cyclosporin-treated renal allografts biopsied at one and twelve months.

Forty-four renal allograft recipients were biopsied routinely one month and one year after transplantation. All patients received cyclosporin and prednisolone. Fifteen patients had at least one rejection episode, while 29 patients never underwent rejection. At one year there were no specific histological features that enabled these two groups to be distinguished. Between one month and one year, interstitial cellular infiltrate and vascular pathology regressed, and renal function steadily improved. Interstitial fibrosis, however, was either unchanged or mildly increased in all patients. There was no correlation between the amount of interstitial fibrosis at one year and either the total dose of cyclosporin or the mean concentration during the first 3 months. Our results suggest that trough, whole blood cyclosporin concentrations, at the upper level of the therapeutic range (800-200 ng/ml), may be safely tolerated during the first 3 months, with little evidence of chronic damage at one year. At one year maintenance doses of cyclosporin can be achieved that are associated with almost normal plasma creatinine concentrations and minimal tubular atrophy and interstitial fibrosis. We expect that such doses may be continued indefinitely.

Immunoglobulin heavy chain switch region restriction fragment length polymorphisms are associated with renal disease.

We describe here, to our knowledge for the first time, associations between polymorphisms at the genomic DNA level in the immunoglobulin gene region and renal diseases which lead to chronic renal failure. Recent studies have shown that protein polymorphisms, present in immunoglobulin (Ig) heavy chains (Gm allotypes) are associated with certain forms of renal disease and with end stage renal failure per se. To investigate this association at the DNA level we have used probes which recognize Ig heavy chain genes and this report describes results obtained with one of these, the S mu switch region probe. With the restriction endonuclease Sst 1 (or the isoschizomer; Sac I) a number of restriction fragment length polymorphisms (RFLP) can be obtained which are recognized by this probe and there is a highly significant association between certain of these and renal disease. This is the first report of Ig switch region polymorphisms being associated with disease, yet our results suggest that S mu RFLP are more closely linked to renal disease than Ig protein polymorphisms.

Blood cyclosporin concentrations and renal allograft dysfunction.

Forty nine renal allograft recipients taking oral cyclosporin suffered 76 episodes of renal dysfunction within six months of transplantation. These episodes were diagnosed as graft rejection or cyclosporin induced nephrotoxicity on the basis of histological findings in allograft biopsy specimens and the response to treatment. Mean predose blood cyclosporin concentrations measured by radioimmunoassay during the week before the onset of renal dysfunction were significantly higher when the cause was cyclosporin toxicity rather than graft rejection (392 v 741 nmol/l (471 v 891 ng/ml). During this period there was a significant association between both the frequency of measurements above 666 nmol/l (800 ng/ml) and the diagnosis of toxicity and the frequency of measurements below 333 nmol/l (400 ng/ml) and the diagnosis of allograft rejection. Cyclosporin measurements made at the time of biopsy and reference to the highest or lowest concentrations measured during the week preceding biopsy were of less value in distinguishing between the two groups. Despite lacking specificity for the parent compound, the radioimmunoassay used produced results which were of clinical value in optimising cyclosporin treatment.

Morphological differentiation between rejection and cyclosporin nephrotoxicity in renal allografts.

In a prospective study of renal dysfunction in 60 consecutive allograft recipients treated with cyclosporin and prednisolone routine renal biopsies at one week and one month after transplantation, as well as for all episodes of renal dysfunction, were performed. The one year graft survival of this group was 88%. In a retrospective clinical analysis of these patients 35 episodes of dysfunction due to rejection, defined by a response to antirejection treatment alone, and 30 episodes due to cyclosporin nephrotoxicity, defined by a response to reduction in cyclosporin dose alone, were identified. The morphological findings from these biopsies were compared with 20 samples from routine biopsies taken from patients with stable renal function. All patients diagnosed as having rejection had a diffuse, interstitial mononuclear cell infiltrate (32 of 35) or arteritis (19 of 35), or both. In contrast, focal mononuclear cell infiltrates were common in both patients with nephrotoxicity and those with stable function (17 of 30 and 14 of 20, respectively). There were no important differences between biopsies from those with nephrotoxicity and those with stable function, except that arteriolar hyalinosis was considerably more common in the nephrotoxic patients than in those with stable function. Many patients with stable function were, in retrospect, in a state of stable mild nephrotoxicity. In our experience rejection should only be diagnosed when there is at least a diffuse interstitial infiltrate or an arteritis. Focal mononuclear cell infiltrates do not denote rejection. The development of arteriolar lesions in the absence of rejection is indicative of nephrotoxicity.

Renal transplantation in patients treated with haemodialysis and short term and long term continuous ambulatory peritoneal dialysis.

Forty two adult patients who had been treated with continuous ambulatory peritoneal dialysis for one to 142 weeks (mean (SD) 38 (36)) received a total of 44 allografted kidneys. Twenty one had been treated with continuous ambulatory peritoneal dialysis for less than 26 weeks (mean 11 (8)) and the other 21 for longer than 26 weeks (mean 64 (35)). These two groups were compared with 55 patients who had been treated with haemodialysis and received a total of 63 grafts. In the group of patients treated with continuous ambulatory peritoneal dialysis azathioprine and low dose prednisolone were used as the immunosuppressive regimen for 20 transplantations in 18 patients, and 24 patients receiving 24 grafts were treated with cyclosporin A and low dose prednisolone. In the group of patients treated with haemodialysis 38 patients receiving 43 grafts were treated with azathioprine and low dose prednisolone, and 20 patients receiving 20 grafts were treated with cyclosporin A and low dose prednisolone. Actuarial survival of patients and grafts at two years was 95% and 72%, respectively, in the continuous ambulatory peritoneal dialysis group compared with 89% and 58%, respectively, in the haemodialysis group. No difference was found in graft survival between short term treatment with continuous ambulatory peritoneal dialysis (72% graft survival) and long term treatment (65% graft survival). In conclusion, continuous ambulatory peritoneal dialysis is suitable treatment for patients awaiting renal transplantation.

Differentiation between allograft rejection and cyclosporin nephrotoxicity in renal-transplant recipients.

In a retrospective study of 60 renal-transplant patients immunosuppressed with cyclosporin no specific clinical features differentiated allograft dysfunction responsive to anti-rejection therapy from dysfunction responsive to reduction in cyclosporin dosage. Histologically, allograft dysfunction responsive to anti-rejection therapy was strongly associated with diffuse interstitial infiltration by mononuclear cells, oedema, and haemorrhage, vascular endothelial-cell proliferation, and infiltration of arterial walls by mononuclear cells. Arteriolar medial hypertrophy and hyalinosis were more commonly found in biopsy specimens from allografts with dysfunction responsive to reduction in cyclosporin dose than in those with dysfunction responsive to anti-rejection therapy and those with stable or improving function. Whole-blood cyclosporin concentrations were significantly lower in patients with dysfunction reversed by anti-rejection therapy than in those with dysfunction reversed by reduction in cyclosporin dose or in those with stable function. There was, however, considerable overlap between these groups, so that individual cyclosporin measurements were of little diagnostic value.

Immunoglobulin C mu gene restriction fragment length polymorphisms associated with chronic renal failure.

The DNA's of 41 patients with various forms of renal disease and of 52 controls were investigated for restriction fragment length polymorphisms (RFLP), using a probe recognising the immunoglobulin Cmu heavy chain gene. With the restriction endonuclease Sst 1, 50 of the controls and 12 of the patients had the expected single 4.3 kilobase (kb) fragment. The remaining 29 patients and 2 controls displayed two patterns of banding, 8 patients and 1 control had a 6.8 kb band in addition to the 4.3 kb, and 21 patients and 1 control had a single band of 5.1 kb. In addition, a significant association between high creatinine levels (greater than 150 mumol/l) and abnormal bands was found (21/25 patients with high levels had abnormal bands compared with only 5/16 patients with normal levels). These results are evidence for an association between the human immunoglobulin heavy chain region and renal disease and they apparently confirm an association already reported at the protein level. However, the new RFLP bands, although reproducible and restricted to renal patients, occur in an area where few polymorphisms would be expected. Further, the association with high creatinine suggests some subtle interaction between the creatinine pathway and this area of the human chromosome.

Renal transplantation after removal and prevention of resynthesis of HLA antibodies.

Plasma exchange and immunosuppression with prednisolone and cyclophosphamide were used to remove HLA antibodies and prevent their resynthesis in five patients awaiting renal transplantation. After treatment HLA antibody titres and reactivities against a panel of donor lymphocytes were considerably reduced and, as a result, these patients received transplants. Four of these patients have successfully functioning transplants; the other patient died as a result of septicaemia with a poorly functioning allograft.

Successful removal and prevention of resynthesis of anti-HLA antibody.

The successful removal and prevention of the resynthesis of an anti-HLA antibody by plasma exchange and immunosuppression in a patient awaiting renal transplantation is described. Before treatment, the patient's serum contained a high titer (greater than 1/50) anti-HLA antibody that reacted with 94% of our lymphocyte donor panel and produced positive cross matches with the lymphocytes from 40 cadaver kidneys. Following treatment, her anti-HLA titers fell to less than 1/10 and her sera reacted with 43% of our lymphocyte donor panel and produced negative crossmatches with lymphocytes from the first two cadaver kidney donors she was tested against. She was successfully transplanted with the second of these kidneys and is now well eight months later, with good graft function.

Successful treatment of middle aged and elderly patients with end stage renal disease.

Many patients over the age of 55 with end stage renal disease in the United Kingdom are denied dialysis or transplantation. Although the reasons are complex, anticipation of a poor prognosis for these patients might explain why most British renal units impose an arbitrary age limit on the acceptance of patients for treatment. A study was therefore conducted to examine the prognosis and quality of life of 84 patients (mean age 59.6 years, range 55-72) accepted into our renal replacement programme from the beginning of 1975. The five year survival of the patients was 62.0% with 78.1% of the survivors either having successful transplants or caring for themselves using home haemodialysis or continuous ambulatory peritoneal dialysis. The results show that in terms of survival, economics, and rehabilitation it is both feasible and reasonable to treat middle aged and elderly patients with end stage renal disease. These patients should therefore not be denied dialysis or transplantation on the basis of age alone, and the lack of resources and other factors that allow this state to persist in Britain should be rapidly redressed.