The impact of late acute rejection after cadaveric kidney transplantation

BACKGROUND

Acute graft rejection (AR) following renal transplantation results in reduced graft survival. However, there is uncertainty regarding the definition, aetiology and long-term graft and patient outcome of AR occurring late in the post-transplant period.

AIM

To determine if rejection episodes can be classified by time from transplantation by their impact on graft survival into early acute rejection (EAR) and late acute rejection (LAR).

MATERIALS AND METHODS

687 consecutive adult renal transplant recipients who received their first cadaveric renal transplant at a single centre. All received cyclosporine (CyA)-based immunosuppression, from 1984 to 1996, with a median follow-up of 6.9 yr. Details were abstracted from clinical records, with emphasis on age, sex, co-morbid conditions, HLA matching, rejection episodes, patient and graft survival.

ANALYSIS

Patients were classified by the presence and time to AR from the date of transplantation. Using those patients who had no AR (NAR) as a baseline, we determined the relative risk of graft failure by time to rejection. The characteristics of patients who had no rejection, EAR and LAR were compared.

RESULTS

Compared with NAR, the risk of graft failure was higher for those patients who suffered a rejection episode. A much higher risk of graft failure was seen when the first rejection episode occurred after 90 d. Thus, a period of 90 d was taken to separate EAR and LAR (relative risk of 3.06 and 5.27 compared with NAR as baseline, p<0.001). Seventy-eight patients (11.4%) had LAR, 271 (39.4%) had EAR and 338 (49.2%) had NAR. The mean age for each of these groups differed (LAR 39.6 yr, EAR 40.8 yr compared with NAR 44 yr, p<0.003). The 5-yr graft survival for those who had LAR was 45% and 10-yr survival was 28%. HLA mismatches were more frequent in those with EAR vs. NAR (zero mismatches in HLA-A: 36 vs. 24%, HLA-B: 35 vs. 23% and HLA-DR: 63 vs. 41%, p<0.003). There was no difference in mismatching frequency between NAR and LAR.

CONCLUSIONS

AR had a deleterious impact on graft survival, particularly if occurring after 90 d. AR episodes should therefore be divided into early and late phases. In view of the very poor graft survival associated with LAR, it is important to gain further insight into the main aetiological factors. Those such as suboptimal CyA blood levels and non-compliance with medication should be further investigated with the aim of developing more effective immunosuppressive regimens in order to reduce the incidence of LAR.

Early graft function and patient survival following cadaveric renal transplantation

BACKGROUND

The influence of events that occur early following renal transplantation such as delayed graft function (DGF) and acute rejection on long-term graft survival has been widely reported, but its association with patient survival has received less attention.

METHODS

We studied 589 patients who received their first cadaveric transplants between 1984 and 1993, all of whom received cyclosporine-based immunosuppression and who had a median follow-up of seven years. The following factors were identified, and both univariate and multivariate analyses were used to determine their association with long-term patient and graft survival: age, sex, duration of pretransplant dialysis, primary renal disease, immediate graft function (IGF), DGF, primary nonfunction (PNF), acute rejection, and serum creatinine at 3, 6, and 12 months.

RESULTS

Patients with PNF had a poorer survival than those with DGF and IGF (P = 0.01), but there was no difference in survival between DGF and IGF (P = 0.54). Good graft function (serum creatinine of less than 200 mumol/liter) at three months was predictive of better long-term patient survival (P = 0.03). Other factors associated with poor patient outcome were older age, diabetes, adult polycystic kidney disease, male gender, and acute rejection. Cardiovascular disease was the most common cause of death (51.8%). Good graft function at three months (P < 0.001) and an absence of rejection episodes (P = 0.01) were associated with better graft survival.

CONCLUSION

Patients with poor levels of early graft function (but not DGF) and those with either acute rejection episodes or early graft loss are at an increased risk of early death. These high-risk groups should be targeted for interventional studies in an attempt to improve patient survival.

Long-term outcome of a prospective randomized trial of conversion from cyclosporine to azathioprine treatment one year after renal transplantation

BACKGROUND

Since the introduction of cyclosporine (CsA), 1-year renal allograft survival has improved, but concern persists about the long-term adverse effects of CsA, especially with respect to renal function and blood pressure. This randomized controlled trial was set up to establish whether withdrawal of CsA would alter long-term outcome.

METHODS

Adult patients who, at 1 year after renal transplantation, had a stable serum creatinine of less than 300 micromol/L and who had not had acute rejection within the last 6 months were eligible for entry. Patients were randomized either to continue on CsA (n=114) or to stop CsA and start azathioprine (Aza, n=102). All patients remained on prednisolone. Median follow-up was 93 months after transplantation (range: 52-133 months).

RESULTS

There was no significant difference in actuarial 10-year patient or graft survival (Kaplan-Meier), despite an increased incidence of acute rejection within the first few months after conversion. Median serum creatinine was lower in the Aza group (Aza: 119 micromol/L; CsA. 153 micromol/L at 5 years after randomization, P=0.0002). The requirement for antihypertensive treatment was also reduced after conversion to Aza; 75% of patients required antihypertensive treatment at the start of the study, decreasing to 55% from 1 year after randomization in the Aza group and increasing to >80% in the CsA group (55% (Aza) and 84% (CsA) at 5 years after randomization, P<0.005).

CONCLUSIONS

Conversion from CsA to Aza at 1 year after renal transplantation results in improvement in both blood pressure control and renal allograft function, and is not associated with significant adverse effects on long-term patient or graft survival.

Pre-operative echocardiographic abnormalities and adverse outcome following renal transplantation

BACKGROUND

Premature cardiovascular disease is now the leading cause of death in renal transplant recipients. Although patients with progressive renal disease have many of the conventional risk factors for cardiovascular disease these do not have the same predictive power as they do in the general population. Echocardiographic abnormalities, notably left ventricular hypertrophy, have been shown to be associated with adverse outcome in patients on dialysis.

METHODS

The echocardiograms were studied from 141 patients who were examined on the eve of renal transplantation between 1988 and 1990 to try to identify factors predicting outcome. Thirty-four patients have since died, 22 of cardiovascular disease. Ninety-three of the survivors and 27 of the dead patients had echocardiographic traces suitable for analysis.

RESULTS

Left ventricular mass index was increased in those patients who died (median 167 vs 134 g/m2; P=0.03), as were end-systolic (4.3 vs 3.4 cm; P<0.01) and end-diastolic (5.8 vs 5.2 cm; P<0.01) diameters. Systolic function was also more severely impaired (fractional shortening, 27 vs 33%; P<0.01). Apart from age, only systolic function and end systolic diameter were independent predictors of outcome in multivariate analysis.

CONCLUSIONS

This pattern of echocardiographic abnormality is similar to that reported in long-term dialysis populations, despite the adverse effects on survival. Moreover, despite potential benefits of transplantation on cardiac function, left ventricular hypertrophy, ventricular dilatation and systolic dysfunction were all associated with adverse outcome following transplantation. We conclude that echocardiography identifies markers for premature death following transplantation and provides targets for therapeutic intervention.

Effect of renal-artery stenting on progression of renovascular renal failure

BACKGROUND

Placement of renal-artery stents has a high technical success rate in atherosclerotic renovascular disease, but little is known about the clinical benefits of the procedure. We monitored renal function serially before and after stent insertion in patients with renovascular renal failure.

METHODS

Renal function was assessed before and after stent placement by means of serial serum creatinine values in 32 patients with atherosclerotic renal-artery stenosis. The effect on the progression of renal failure was analysed in 23 patients by comparison of the reciprocal slopes of serum creatinine versus time plots before and after stent placement.

FINDINGS

33 transluminal stents were placed in 32 patients with atherosclerotic renovascular disease. Immediate patency was achieved in all cases: the angiographic restenosis rate at 6 months was 12% (n = 24). One patient died after a procedure-related haemorrhage. Median diastolic blood pressure was significantly lower after stenting than before (95 [IQR 86-103] vs 87 [81-90] mm Hg; p > 0.01) but the requirement for antihypertensive drugs was unchanged. Renal function improved or stabilised in 22 (69%) of the 32 patients. Progression of renal failure was significantly slowed after the procedure; the mean (SE) of the slopes of reciprocal serum creatinine values was -4.34 (0.85) L mumol-1 day-1 before stent placement, and -0.55 (1.0) L mumol-1 day-1 after stent placement (p < 0.01, two-sample t test).

INTERPRETATION

Renal-stent placement in selected patients slows the progression of renovascular renal failure and may delay the need for renal replacement therapy.

The need for renal replacement therapy in Scotland

Each year 80-100 people per million of the population develop end stage renal failure and are medically suitable for renal replacement therapy. This need has been met in Scotland in each of the last three years. With current knowledge there is no prospect of measures to prevent renal disease affecting this number in the foreseeable future. The number of patients on renal replacement therapy in Scotland will increase over the next 15 years to approximately 160% of the current number. The mean age of patient on replacement therapy will increase progressively over the next 15 years. The increase in numbers will be in patients receiving 'in centre' haemodialysis and in those with functioning renal transplants. To meet this increase an approximately 3-4 increase in the current 'in centre' haemodialysis facilities will be required. Additional haemodialysis centres should be established to reduce the time spent by patients travelling for treatment and to avoid centres becoming 'impersonal' by becoming too large. Moves to increase the transplantation rate should be encouraged as transplantation offers the best quality of life for patients. Research should be directed towards improving long term graft survival.

Ranitidine reduces phosphate binding in dialysis patients receiving calcium carbonate

BACKGROUND

In a previous controlled study we showed that ranitidine significantly reduced the phosphate binding of aluminium hydroxide in patients with renal failure, probably increasing intragastric pH.

METHODS

In this study we have investigated the effect of ranitidine on the phosphate binding of calcium carbonate in fifteen dialysis patients. Ranitidine 300 mg or a placebo tablet was taken before breakfast for two 4-week periods in a double-blind crossover trial with no washout period. The mean daily dose of calcium carbonate was 2 g and neither the dose nor the patient's diet was changed during the study period. Blood was taken at 2-weekly intervals for serum phosphate, calcium, albumin, and alkaline phosphatase measurements, and at the end of each treatment period for parathyroid hormone (PTH) level.

RESULTS

Serum phosphate concentrations were significantly higher during the ranitidine than the placebo phase, 1. 78 (+/-0.43 SD) versus 1.59 (+/-0.49 SD) mmol/l (P<0.001). Serum calcium, albumin, PTH, and alkaline phosphatase concentrations did not differ between the two treatment periods.

CONCLUSION

This study shows that ranitidine has a significant adverse effect on the phosphate binding of calcium carbonate in patients with renal failure.

Longitudinal evaluation of peritoneal macrophage function and activation during CAPD: maturity, cytokine synthesis and arachidonic acid metabolism

The release of cytokines and prostaglandins (PG) by peritoneal macrophages (PM luminal diameter of) may influence the cytokine network controlling peritoneal inflammation and in the long-term the function of the peritoneum as a dialysis membrane. In the present study, an evaluation of the long-term effects of peritoneal dialysis on the release of cytokines and prostaglandins, and the expression of surface markers of cellular maturation on blood and mononuclear cells has been performed in patients during their first year on CAPD. Spontaneous release of tumour necrosis factor alpha (TNF alpha) and interleukins 6 (IL-6) by PM luminal diameter of, after 4 or 24 hours in culture, increased significantly with time on CAPD, while there was a small but significant decrease in release of prostaglandin E2 (PGE2). Production of TNF alpha and IL-6 was enhanced following incubation of the cells with lipopolysaccharide (LPS), but the effect of LPS was proportionally greater on blood monocytes than on PM luminal diameter of. There was a significant increase in the concentrations of PGE2 and 6-keto-prostaglandin F1 alpha in overnight dwell peritoneal dialysis effluent with time on CAPD. The levels of TNF alpha and IL-6 in uninfected PDE were below the detection limit of the immunoassay over the whole time period studied. Expression of CD15, which correlates with immaturity, by PM luminal diameter of and blood monocytes increased with time on CAPD, while expression of CD11c, a marker of maturation, decreased on blood monocytes, but did not change significantly on PM luminal diameter of. There was also a slight increase in expression of transferrin receptor in both PM luminal diameter of and monocytes, but this did not reach statistical significance. These findings suggest that peritoneal macrophages and blood monocytes isolated from CAPD patients over a one year period become increasingly immature with time, and this is accompanied by a significant modulation of their ability to secrete inflammatory cytokines. Dysregulation of macrophage function may have important consequences with respect to inflammatory processes and the long-term function of the peritoneal membrane in CAPD patients.

Treatment of postrenal transplant erythrocytosis. Long-term efficacy and safety of angiotensin-converting enzyme inhibitors

Fifty-two patients with postrenal transplant erythrocytosis were treated with an angiotensin-converting enzyme inhibitor (lisinopril or enalapril) for a median of 13 months (range 0-44). A significant fall in haemoglobin of 1.8 +/- 1.6 g dl-1 (range - 0.8 to 6.6) occurred over the first 3 months (p < 0.0001). The haemoglobin then remained stable for as long as 3 years. Both enalapril and lisinopril were equally effective. Therapy was withdrawn in 16 patients (31%) because of decline in renal function (6), anaemia (5), hypotension (3), hyperkalaemia (1) or erectile impotence (1) - complications which were all reversible. Angiotensin-converting enzyme inhibitors in low dose are a safe and effective long-term therapy for postrenal transplant erythrocytosis.

Colour Doppler ultrasound in renal transplant artery stenosis: which Doppler index?

A prospective study comparing colour Doppler ultrasound (US) with the 'gold standard' of intra-arterial digital subtraction angiography in the evaluation of renal transplant artery stenosis was performed. Both the intrarenal vessels and the transplant renal artery were examined by Doppler US. Diagnostic arteriography was performed only if, on Doppler, the peak systolic velocity in the transplant renal artery exceeded 1.5 ms-1. Of 109 patients, the transplant artery could not be visualized using colour Doppler US in three, and these were omitted from statistical analysis. Of the remaining 106 patients, 31 had a peak systolic velocity greater than 1.5 ms-1 in the transplant renal artery and were referred for DSA. Of the multiple renal Doppler indices recorded, the peak systolic velocity in the transplant artery was the best discriminating measurement for the detection of renal artery stenosis. A peak systolic velocity of > or = 2.5 ms-1 in the transplant renal artery had a sensitivity of 100% and a specificity of 95% for the detection of renal artery stenosis ( > 50% diameter reduction). Although a significant difference in Pulsatility Index, Resistive Index, Acceleration Index and Acceleration Time was recorded from the intrarenal vessels in the angiographically normal and stenosed groups with Doppler, these measurements were less useful as discriminating diagnostic tests. In conclusion, the peak systolic velocity in the transplant renal artery is the most sensitive Doppler criterion for renal artery stenosis and is sensitive and specific enough to be used as a screening test. The intrarenal acceleration time and index should not be used in isolation.

Polymorphisms in angiotensin-converting-enzyme gene and progression of IgA nephropathy

We have investigated the influence of the functional insertion (I) and deletion (D) polymorphism in intron 16 of the gene for angiotensin-converting enzyme (ACE) in a retrospective study of 100 patients with IgA nephropathy. There was no difference in genotype frequency compared with normal subjects. However, patients homozygous for the D allele tended to present at an earlier age (medians: DD, 33; ID, 34; II, 42 years) and to require renal replacement therapy at a younger age (medians 37, 42, and 48 years, respectively). The rate of progression was significantly worse in patients homozygous for the D allele. The DD genotype is associated with increased severity of disease in patients with IgA nephropathy.

Long-term outcome of the use of OKT3 to treat steroid-resistant acute renal allograft rejection

OKT3 was used to treat steroid-resistant acute renal allograft rejection in 30 of 496 adult patients transplanted over a 6-year period. Rejection was reversed (defined as a fall in serum creatinine by 50% or more within 30 days of treatment with OKT3) in 40% of cases. Successful reversal was significantly more likely when rejection occurred shortly after transplantation (t ratio -2.53; P = 0.019). The long-term outcome was disappointing; the actuarial graft survival at 1 year from the start of treatment with OKT3 was 42%, and no grafts have thus far survived longer than 3 years. Graft survival was shorter in older patients (coefficient/standard error 2.226; P < 0.05), and no other predictor of long-term outcome was identified. Patient survival at 3 years was 88%. Serious infection occurred in 33% of patients, with two deaths. Our experience suggests that treatment with OKT3 is unlikely to reverse acute renal allograft rejection in more than half of patients where rejection is resistant to steroids. Although long-term graft survival occurred in a few cases, the overall long-term outcome was disappointing, particularly in older patients. Finally, our analysis indicates the difficulty of predicting which patients will derive long-term benefit when OKT3 is used to treat steroid-resistant rejection.

Crescentic glomerulonephritis: experience of a single unit over a five year period

Crescentic glomerulonephritis is a well defined pathological lesion occurring in a range of renal and systemic diseases. We have retrospectively reviewed the aetiology, clinical features and outcome in 60 patients presenting over a five and a half year period. Most patients were elderly (median age 61 years, range 16-84 years). The majority presented with severe renal impairment, 32 requiring dialysis at admission. The degree of glomerular crescent formation on biopsy was closely related both to initial dialysis dependence and the ensuing response to immunosuppression. Forty-three patients received immunosuppressive treatment. A beneficial response was seen in 40% of patients requiring dialysis, and in 88% of those with less severe renal impairment. A high early mortality was apparent (30% within three months), exclusively affecting elderly patients (all > 60 years), with advanced renal failure (all dialysis dependent), the majority of whom (15 out of 18) had been immunosuppressed. The results suggest that the benefits of immunosuppression in this group may be outweighed by the complications of treatment.

Histological and electron microprobe studies of mineralisation in aluminium-related osteomalacia

AIMS

To determine a possible mechanism to explain the presence of aluminium lines within fully calcified bone in aluminium-related osteomalacia.

METHODS

Fifty five bone cases shown by bone biopsy to be aluminium-related osteomalacia were studied. In 38 specimens aluminium lines were identified within calcified bone by means of the Aluminon stain and a characteristic form of patchy mineralisation was seen within thickened osteoid seams. Five representative examples were analysed quantitatively by histomorphometry and electronprobe X-ray microanalysis and compared with five cases of vitamin D deficiency-related osteomalacia which also had patchy mineralisation.

RESULTS

The patchy calcification occupied 40 +/- 8% (mean +/- SEM) of the osteoid and consisted of small focal deposits (less than 40 microns diameter), often (52%) around osteoid osteocytes (probably an underestimate of the association), and larger areas that extended to the aluminium lines at the underlying mineralisation front. Small and large mineralisation nuclei were seen ultrastructurally in the patchy calcification. Quantitative electronprobe X-ray microanalysis showed that calcium concentrations and calcium:phosphorus ratios in the mineralisation nuclei and in the superficial layer of the fully calcified bone of the aluminium-related osteomalacia cases were significantly less than values measured at similar sites in the vitamin D deficiency-related osteomalacia cases. Furthermore, aluminium could not be detected by means of this technique at the mineralisation front or along cement lines in these specimens.

CONCLUSIONS

Calcification can occur in thickened osteoid seams in osteomalacia. It can begin around osteoid osteocytes as small deposits that enlarge within the osteoid and extend to the underlying mineralisation front or cement line where aluminium lines may become trapped. Complete calcification of osteoid could account for the presence of aluminium lines within fully calcified bone. The Aluminon stain appears to be a more sensitive method for the detection of aluminium in bone than electronprobe X-ray microanalysis.

The spectrum of chronic liver disease in renal transplant recipients

Chronic liver disease has been reported to be an important cause of late morbidity and mortality in renal transplant recipients. We have examined the prevalence and nature of chronic liver disease among 538 patients with functioning renal allografts managed at the Western Infirmary, Glasgow, between 1980 and 1989. Thirty-seven patients (7 per cent) satisfied biochemical criteria for chronic liver dysfunction. Liver biopsies were obtained from 24 of these, and autopsy tissue was available from three other patients. Chronic hepatitis of variable severity was present in 15 patients, haemosiderosis in 12 patients and nodular regenerative hyperplasia in five patients. Nineteen patients (51 per cent) had serological evidence of infection with the hepatitis C virus, and one of these developed chronic hepatitis B and D infection as well. Although a variety of chronic liver diseases occurred in our transplant population, the frequency of serious sequelae from liver dysfunction was much lower than that reported from transplant centres in other countries.

Autonomous hyperparathyroidism not associated with increased aluminum absorption

A single 6-g dose of aluminum hydroxide was given to eight patients on regular hemodialysis before and 3 days after parathyroidectomy (PTX). Serum aluminum levels were measured before and after 5 h after ingestion of aluminum hydroxide to examine indirectly the effects on absorption of aluminum from the gastrointestinal tract of both high and low parathyroid hormone (PTH). Plasma PTH levels fell significantly from 2,724 +/- 1,830 ng/l (mean +/- 1 SD) before PTX to 352 +/- 63 ng/l after PTX. However, no significant change was detected in serum aluminum levels before or after PTX (1.45 +/- 0.96 to 1.92 +/- 0.88 mumol/l before PTX; 2.02 +/- 1.41 to 2.89 +/- 1.19 mol/l after). These findings indicate that in patients with chronic renal failure, high plasma levels of PTH are not associated with significant increases in serum aluminum concentrations after ingestion of a large quantity of aluminum hydroxide. Parathyroid hormone may not enhance intestinal absorption of aluminum in humans.

Expression of transferrin receptors by monocytes and peritoneal macrophages from renal failure patients treated by continuous ambulatory peritoneal dialysis (CAPD)

Approximately 20% of monocytes and peritoneal macrophages from renal failure patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were transferrin-receptor (TfR) positive by immunofluorescence, whereas cells from normal controls were generally TfR negative, as were monocytes from rheumatoid arthritis patients and from renal failure patients treated by haemodialysis. There was a significant correlation between the length of time on CAPD and the proportion of TfR-positive blood monocytes. CAPD peritoneal macrophages possessed 6.7-37.1 x 10(3) transferrin binding sites per cell, with a Ka of 3-25 x 10(7) mol l-1. In culture, monocytes from CAPD patients showed a progressive decrease in TfR expression, while in contrast about 20% of monocytes from normal controls which were originally 100% TfR negative expressed TfR after 3 days in culture. These findings indicate that regulation of TfR in monocytes/macrophages is complex, and that frequent removal of peritoneal cells during dialysate exchange may place a strain on the bone marrow, resulting in the release of an increasingly immature population of TfR positive monocytes to the circulation in CAPD patients.

Interaction of aluminium and gallium with human lymphocytes: the role of transferrin

Aluminium-transferrin (Al-Tf) and gallium-transferrin caused a dose-dependent decrease in proliferation of human peripheral blood lymphocytes cultured for 3 days with phytohaemagglutinin (PHA). Addition of apotransferrin reduced the inhibitory effect. Al added as AlCl3 or aluminium citrate had no effect, and there was no significant difference in the response of cells from renal failure patients with or without high serum Al levels or controls. Lymphocytes cultured in the presence of Al-Tf showed a dose-dependent uptake of Al, whereas uptake from aluminium citrate was low and not dose-dependent. Uptake from AlCl3 was very high but probably involved a nonspecific uptake mechanism. Levels of Al in freshly isolated lymphocytes were approximately 1.6 ng/10(6) cells, there being no difference between cells from patients and controls. It is concluded that Al, when bound to transferrin, may have a detrimental effect on lymphocyte function and might contribute to the decreased immune responsiveness of renal failure patients on haemodialysis. However, lymphocyte Al levels are probably not useful as a marker of Al overload in such patients.

Ultrasound changes in sclerosing peritonitis following continuous ambulatory peritoneal dialysis

Sclerosis of the peritoneum, with encapsulation of the small bowel is one of the most serious complications of continuous ambulatory peritoneal dialysis (CAPD), and carries a high mortality. The abnormalities seen on ultrasound are described for 14 patients and comprise increased small bowel peristalsis, tethering of the bowel to the posterior abdominal wall, intraperitoneal echogenic strands and, in the late stages of the disease, membrane formation. Optimal visualization of these features in the early stages of the disease was obtained by examining the patients with dialysis fluid present in the abdomen. Sclerosing peritonitis should be suspected in patients being treated by CAPD who develop abdominal pain and progressive loss of ultrafiltration and subsequent investigation should include the use of ultrasound.

The effect of conversion from cyclosporin to azathioprine on renin-containing cells in renal allograft biopsies

Renal biopsies were examined from 17 renal transplant recipients before and after conversion from cyclosporin to azathioprine, and in 17 patients who remained on cyclosporin. All patients had stable renal function. We used an immunoperoxidase technique with an antiserum to human renin to identify renin-containing cells. We demonstrated hyperplasia of renin-containing cells in patients treated with cyclosporin. Numbers of renin-containing cells decreased after conversion to azathioprine. We suggest that local activation of the intrarenal renin-angiotensin system could mediate the effects of cyclosporin on renal haemodynamics. This could play a role in the pathogenesis of cyclosporin nephrotoxicity and cyclosporin hypertension.

In vitro studies on lymphocyte Fc gamma receptor blocking factors in human renal transplantation

In this study we have confirmed our earlier observation that the presence in pre-transplant serum of a high-molecular-weight lymphocyte Fc gamma receptor blocking factor correlates with improved human renal allograft survival. This factor was found to bind preferentially to B cells and to impair B cell function in vitro.

Isolation and characterization of a high molecular weight lymphocyte Fc gamma receptor-blocking factor associated with renal allograft survival

We have confirmed our previous observation that improved human renal allograft survival is associated with the presence in pre-transplant serum of a high molecular weight lymphocyte Fc gamma receptor-blocking factor. Serum fractionation studies suggest that this factor is a complex protein consisting of IgG together with an IgG-binding protein which has an apparent molecular weight of approximately 60 kD.

Outcome of renal replacement treatment in patients with diabetes mellitus

OBJECTIVE

To compare the outcome of renal replacement treatment in patients with diabetes mellitus and in non-diabetic patients with end stage renal failure.

DESIGN

Retrospective comparison of cases and matched controls.

SETTING

Renal unit, Western Infirmary, Glasgow, providing both dialysis and renal transplantation.

PATIENTS

82 Diabetic patients starting renal replacement treatment between 1979 and 1988, compared with 82 matched non-diabetic controls with renal failure and 39 different matched controls undergoing renal transplantation.

MAIN OUTCOME MEASURES

Patient characteristics, history of smoking, prevalence of left ventricular hypertrophy and myocardial ischaemia at start of renal replacement treatment; survival of patients with renal replacement treatment and of patients and allografts with renal transplantation.

RESULTS

The overall survival of the diabetic patients during the treatment was 83%, 59%, and 50% at one, three, and five years. Survival was significantly poorer in the diabetic patients than the controls (p less than 0.001). Particularly adverse features for outcome at the start of treatment were increasing age (p less than 0.01) and current cigarette smoking (relative risk (95% confidence interval) 2.28 (0.93 to 4.84), p less than 0.05). Deaths were mainly from cardiac and vascular causes. The incidence of peritonitis in patients on continuous ambulatory peritoneal dialysis was the same in diabetic patients and controls (49% in each group remained free of peritonitis after one year), and the survival of renal allografts was not significantly worse in diabetic patients (p less than 0.5).

CONCLUSIONS

Renal replacement treatment may give good results in diabetic patients, although the outlook remains less favourable than for non-diabetic patients because of coexistent, progressive vascular disease, which is more severe in older patients.

Release of hydrogen peroxide and expression of HLA-DR and transferrin receptors by monocytes and peritoneal macrophages from patients undergoing continuous ambulatory peritoneal dialysis and normal controls

Peritoneal macrophages from patients on continuous ambulatory peritoneal dialysis (CAPD) were investigated with respect to their ability to release H2O2 and express HLA-DR and transferrin receptors (TfR). Release of H2O2 and the proportion of cells expressing HLA-DR were significantly reduced in CAPD macrophages compared with normal peritoneal macrophages but were both similar to blood monocytes. In contrast, about 17% of CAPD peritoneal macrophages and 23% of CAPD blood monocytes expressed TfR but normal peritoneal macrophages and blood monocytes were always negative. These results suggest that the peritoneal macrophages from CAPD patients are relatively immature cells, possibly due to the rapid turnover of cells in CAPD.

Low calcium dialysate and high-dose oral calcitriol in the treatment of secondary hyperparathyroidism in haemodialysis patients

We treated nineteen haemodialysis patients with secondary hyperparathyroidism with increasing oral doses of 1,25 dihydroxycholecalciferol (calcitriol) over a 12-week period and used low calcium dialysate (1.0 mmol/l) to prevent hypercalcaemia. Nine patients received daily calcitriol and ten received calcitriol thrice weekly, and at the end of the study the mean doses were 2.0 micrograms daily and 2.6 micrograms thrice weekly respectively. The regimen was well tolerated with nine episodes of mild hypercalcaemia, none of which were symptomatic. Mean PTH and alkaline phosphatase concentrations decreased from 62.0 pmol/l (15-125) to 22.0 pmol/l(1-70) (P less than 0.01), and 144 IU/l (48-461) to 123 IU/l (61-346) (P less than 0.05) respectively. Mean serum calcium increased from 2.33 mmol/l (2.05-2.55) to 2.52 mmol/l (2.26-2.67) (P less than 0.01). There were no significant changes in serum phosphate, magnesium, or aluminium concentrations and there were no significant differences in outcome between patients receiving daily therapy compared to those receiving it thrice weekly. A combination of high-dose oral calcitriol and low calcium dialysate can reverse secondary hyperparathyroidism without causing hypercalcaemia and these results suggest a benefit over conventional low-dose calcitriol.

Acute renal failure due to McArdle's disease

A 37-year-old previously fit man developed acute renal failure associated with rhabdomyolysis following a brief period of strenuous exercise. Subsequent muscle biopsy and ischaemic arm exercise confirmed the diagnosis of McArdle's disease. This case illustrates that McArdle's disease can present with acute renal failure in the absence of a past history of exercise-induced muscle pain and stiffness.

CAPD disconnect systems

Increasingly complex devices to carry out exchanges in continuous ambulatory peritoneal dialysis (CAPD) have failed to improve on the peritonitis rates of the Italian 'Y' system which uses simple flushing along with antiseptic to sterilise the connectors. Other systems based on similar principles have produced satisfactory peritonitis rates while offering patients the ability to dispense with most of the tubing and the bag between exchanges. The enthusiasm of patients for the principle of disconnection has led to a rapid increase in the use of these systems. CAPD disconnect systems offer nephrologists reasonable peritonitis rates and patients further freedom combined with convenience and safety.

The effect of random blood transfusions on immunoglobulin production by peripheral blood mononuclear cells from uraemic patients

The effect of blood transfusion on humoral immunity in chronic renal failure was studied by examining immunoglobulin production in vitro, in patients awaiting renal transplantation. Pokeweed mitogen (PWM) induced IgG plaque formation was normal in non-transfused uraemic patients while both spontaneous and Staphylococcus aureus Cowan I (SAC) induced immunoglobulin production were reduced. Five to ten units of third party blood transfusion reduced PWM-driven B cell differentiation, but had no effect on SAC-induced plaque formation, while spontaneous production of immunoglobulin was either enhanced or unaffected. As it is known that the response to SAC is less affected by suppressor T cell activity than that to PWM, these differences in the inhibitory effects of blood transfusion on B cell differentiation are further evidence that transfusion may act by increasing suppressor T cell activity.

In vitro analysis of B lymphocyte function in uraemia

We have investigated the immune responses in vitro of uraemic patients undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis. Twenty-five healthy subjects were also studied as controls. In uraemic patients, the number of T and B lymphocytes were within the normal range, but proliferative responses to phytohaemagglutinin (PHA) were impaired. Spontaneous immunoglobulin plaque forming cell (PFC) responses by peripheral blood mononuclear cells (PBMC) from uraemic patients were significantly lower than those of healthy subjects. The PFC response of uraemic PBMC to the T cell independent polyclonal B cell activator (PBA) Epstein-Barr virus (EBV) was comparable to the response of the healthy subjects, indicating that uraemic B cells are still capable of synthesizing immunoglobulin. Pokeweed mitogen (PWM) induced PFC responses of uraemic PBMC were also normal, whereas the response to another T cell dependent B cell activator, Staphylococcus aureus Cowan I (SAC), was very low. Addition of indomethacin to PWM- and SAC-activated cultures of uraemic PBMC enhanced the PFC response to SAC, but had little effect on the PWM response. As full differentiation of B cells in response to SAC depends on helper T cells, we conclude that a defect in T lymphocyte function accounts for the reduced spontaneous and SAC induced production of immunoglobulin by uraemic PBMC. This defect may be mediated by an indomethacin-sensitive mechanism.

Correlation between high-molecular-weight Fc gamma-receptor-blocking factors in serum and renal allograft survival

In this study, we have demonstrated the occurrence of IgG class noncytotoxic, lymphocyte Fc gamma-receptor-blocking antibodies in a proportion of sera obtained from transfused uremic patients. The presence of these antibodies was not found to correlate with subsequent renal allograft survival. Serum fractionation studies did however reveal a striking correlation between graft survival and Fc gamma-receptor blocking mediated by a serum factor(s) with a sedimentation coefficient of greater than 19S. The precise nature of this factor remains to be clarified.

The visual status of diabetics on renal replacement therapy (RRT)

The visual status of 48 patients with end-stage diabetic nephropathy who were undergoing treatment either by dialysis or transplantation was assessed. At the time of starting dialysis, the vision was good in 27 (56 per cent), impaired in 7 (15 per cent) and of navigating standard only in 12 (25 per cent) while the remaining 2 (4 per cent) had no useful vision. During the time on dialysis and/or following transplantation, vision improved in 6 patients (12 per cent), deteriorated in 9 (19 per cent) and remained unchanged in 33 (69 per cent). Changes in the degree of retinopathy in the 96 eyes resulting either from treatment of the renal failure or laser therapy were noted. The reasons for any changes in vision and the effect of ophthalmic treatment will be discussed.