Colin D. Short

Antiphospholipase A2 Receptor Antibody Titer and Subclass in Idiopathic Membranous Nephropathy

The phospholipase A(2) receptor (PLA(2)R) is the major target antigen in idiopathic membranous nephropathy. The technique for measuring antibodies against PLA(2)R and the relationship between antibody titer and clinical characteristics are not well established. Here, we measured anti-PLA(2)R (aPLA(2)R) antibody titer and subclass in a well defined cohort of 117 Caucasian patients with idiopathic membranous nephropathy and nephrotic-range proteinuria using both indirect immunofluorescence testing (IIFT) and ELISA. We assessed agreement between tests and correlated antibody titer with clinical baseline parameters and outcome. In this cohort, aPLA(2)R antibodies were positive in 74% and 72% of patients using IIFT and ELISA, respectively. Concordance between both tests was excellent (94% agreement, κ=0.85). Among 82 aPLA(2)R-positive patients, antibody titer significantly correlated with baseline proteinuria (P=0.02). Spontaneous remissions occurred significantly less frequently among patients with high antibody titers (38% versus 4% in the lowest and highest tertiles, respectively; P<0.01). IgG4 was the dominant subclass in the majority of patients. Titers of IgG4, but not IgG1 or IgG3, significantly correlated with the occurrence of spontaneous remission (P=0.03). In summary, these data show high agreement between IIFT and ELISA assessments of aPLA(2)R antibody titer and highlight the pathogenetic role of these antibodies, especially the IgG4 subclass, given the observed relationships between aPLA(2)R titer, baseline proteinuria, and outcome.

Anti-PLA2R antibodies measured by ELISA predict long-term outcome in a prevalent population of patients with idiopathic membranous nephropathy

Antibodies to the phospholipase A2 receptor 1 (PLA2R1) have been reported in 70% of cases of idiopathic membranous nephropathy (IMN). The genetic susceptibility of IMN has been accounted for by HLA DQA1 and PLA2R1 genes. Here we retrospectively quantified PLA2R antibodies by ELISA, and genotyped DQ alleles and PLA2R1 single-nucleotide polymorphisms for association with clinical criteria for disease activity at the time of first sample and with outcome over a median total follow-up of 90 months. In 90 prevalent patients with biopsy-proven IMN, anti-PLA2R antibodies were present in 75% of patients with IMN with active disease and were significantly higher than in patients in partial or complete remission at the time of antibody measurement. There was a differential IgG subclass response (4>2>3>1) at an early stage, i.e., within 6 months of biopsy. Levels of PLA2R antibodies were significantly linked to DQA1*05:01 and DQB1*02:01. Survival analysis of patients with IMN showed that PLA2R antibodies are significantly linked with outcome. Thus, high levels of PLA2R antibodies are linked with active disease and a higher risk of declining renal function during follow-up. Future therapeutic trials in IMN should monitor anti-PLA2R, as patients with a high antibody burden may benefit from earlier therapeutic intervention.

Fundus changes in mesangiocapillary glomerulonephritis type II: clinical and fluorescein angiographic findings.

Previously we have demonstrated a deposit in Bruchs membrane in a single case of mesangiocapillary glomerulonephritis type II. We studied a group of patients with this disease and described extensive clinical and fluorescein angiographic abnormalities, which were in marked contrast to the findings in a group of patients with other forms of glomerulonephritis. This finding contributes to our understanding of the pathophysiology of the complex of the retinal pigment epithelium, Bruchs membrane, and choriocapillaris.

Transforming growth factor beta 1 in renal allograft recipients.

Transforming growth factor beta (TGF beta 1) is a prosclerotic cytokine implicated in several disease processes. Recent reports have demonstrated a role for TGF beta 1 in experimental models of glomerulonephritis, focusing attention on the relevance of TGF beta to renal fibrogenesis in human disease. The study reported here was designed to investigate whether circulating, active TGF beta 1 could be detected in renal allograft recipients, and whether plasma levels correlated with episodes of rejection, a process involving both inflammation and fibrosis. We have developed an ELISA assay for active TGF beta 1 using commercially available antibodies, and measured plasma levels in 43 healthy controls, 11 patients with membranous nephropathy (MN) and impaired renal function, 17 transplant recipients with stable renal function, 27 patients with acute cellular rejection, 7 patients with chronic vascular rejection, and 10 patients with acute tubular necrosis and/or cyclosporine toxicity. In the last three groups diagnoses were biopsy-proved, and all samples were collected at the time of biopsy. TGF beta 1 was also measured in urine samples from 8, 11, 0, 9, 4, and 7 individuals, respectively, from each group. TGF beta 1 was not detected in plasma from any of the healthy controls or any of the MN patients, (detection limit of assay 0.1 ng/ml). By comparison, it was significantly increased in all groups of transplant recipients (unpaired t test, P < 0.01), but there were no significant differences between the transplant groups. Plasma TGF beta 1 level did not correlate with renal function (estimated by either serum creatinine or reciprocal creatinine), kidney donor age, recipient age, time since transplantation, or cyclosporine plasma trough level. TGF beta 1 was found in every urine sample tested from healthy controls, with a range from 1 ng/ml to 35 ng/ml. Among the 20 transplant patient urines tested, 2 were negative, 18 were positive but within the range determined for the healthy controls. There were no significant differences between the groups.

Influence of immunosuppressive therapy on lipoprotein(a) and other lipoproteins following renal transplantation

Coronary heart disease (CHD) is more common in patients with chronic renal failure and is a major cause of death after renal transplantation. Elevated serum levels of lipoprotein(a) (Lp(a)) are a known risk factor for CHD in the general population and levels have been reported to be increased in renal transplant recipients. It has been suggested that cyclosporin may elevate Lp(a) levels. We therefore measured the serum concentration of Lp(a) in 50 renal transplant recipients who were receiving cyclosporin alone as immunosuppressive therapy and 50 who were treated with azathioprine and prednisolone, but not cyclosporin. The patients attended two renal transplant centres, one where cyclosporin alone was used as immunosuppressive treatment when possible and another where many patients commenced on azathioprine and prednisolone remain on this medication rather than cyclosporin. Patients in each group were matched for age and sex, but the time since transplantation was greater in those not receiving cyclosporin. Transplant function, obesity and the underlying cause of renal disease were similar in both groups of patients. Median Lp(a) concentration in the cyclosporin monotherapy group was 32.0 (range <0.8-140.3) mg/dl and was significantly (p < 0.05) greater than that of the azathioprine and prednisolone group which was 18.3 (range <0.8-167.7) mg/dl. The serum high-density lipoprotein (HDL) cholesterol concentration, which was 1.24 +/- 0.39 mmol/l (mean +/- SD) in patients receiving cyclosporin, was significantly (p < 0.05) less than that of those treated with azathioprine and prednisolone in whom it was 1.41 +/- 0.40 mmol/l. The lower level in those on cyclosporin was due to a decrease in the HDL2 subfraction. Serum lipid and lipoprotein concentrations were otherwise similar in the two groups of patients. The serum level of Lp(a) after renal transplantation may be influenced by the choice of immunosuppressive therapy.

Prevalence and management of anaemia in renal transplant recipients: data from ten European centres.

Background: Although it is a known predictor of mortality, there is a relative lack of recent information about anaemia in kidney transplant recipients. Thus, we now report data about the prevalence and management of post-transplant anaemia (PTA) in Europe 5 years after the TRansplant European Survey on Anemia Management (TRESAM) study. Methods: In a cross-sectional study enrolling the largest number of patients to date, data were obtained from 5,834 patients followed at 10 outpatient transplant clinics in four European countries using the American Society of Transplantation anaemia guideline. Results: More than one third (42%) of the patients were anaemic. The haemoglobin (Hb) concentration was significantly correlated with the estimated glomerular filtration rate (eGFR) (r = 0.4, p < 0.001). In multivariate analysis, eGFR, serum ferritin, age, gender, time since transplantation and centres were independently and significantly associated with Hb. Only 24% of the patients who had a Hb concentration <110 g/l were treated with an erythropoiesis-stimulating agent. The prevalence of anaemia and also the use of erythropoiesis-stimulating agents were significantly different across the different centres, suggesting substantial practice variations. Conclusions: PTA is still common and under-treated. The prevalence and management of PTA have not changed substantially since the TRESAM survey.

Serum and urine IL-6 and TNF-α in renal transplant recipients with graft dysfunction

The object of the study presented here was to test whether measurement of blood or urine IL-6 or TNF-α could discriminate between the most common causes of renal allograft dysfunction, thus avoiding a biopsy. We present data here in which serum and urine IL-6 and TNF-α levels were measured at the same time as a diagnostic renal biopsy was performed. TNF-α and IL-6 were measured by sandwich ELISA. Thirty patients had acute cellular rejection, 18 had acute tubular necrosis/CsA toxicity, and 9 had chronic vascular rejection. There was no difference in the levels of IL-6 measured in serum and urine among the three categories of graft dysfunction (t < 1.31; P >0.20). A similar result with considerable overlap between the groups was seen with TNF-α (t < 0.78; P > 0.44). Stratifying the results according to the precise immunosuppressive therapy, CsA dose, body weight, CsA level, body temperature, serum creatinine, the number of previous rejection episodes, original cause of renal failure, or the time elapsed since the transplant did not alter the results. The ratio of serum IL-6 divided by trough CsA level was compared among the three groups and there was no significant difference among them (t < 1.79; P > 0.09). In the light of our results, we therefore suggest that previously published reports of the clinical value of serum and or urine IL-6 and or TNF-α in relatively small numbers of patients, not all of whom had been biopsied and in whom rigorous clinical and statistical criteria had not been met, should be viewed with caution.

Evidence that matching for HLA antigens significantly increases transplant survival in 1001 renal transplants performed in the northwest region of England

In the 20-year period from March 1968 to March 1988, 860 patients received 1001 renal transplants in the Northwestern Regional Renal Transplant Unit at Manchester Royal Infirmary. Through a continuing policy of avoiding mismatches for HLA antigens and lymphocytotoxic antibody crossmatching, transplant survival rates were found to correlate with the degree of HLA-A and B antigen mismatching from 1968 to 1978 and with HLA-B and DR antigen mismatching from 1979 to 1988. Mismatching for HLA-B and DR antigens was also found to correlate with transplant survival in highly sensitized patients and in patients transplanted since 1981, the “cyclosporine era.” Recipients who were HLA-DR1 positive were found to have the highest graft survival compared to recipients negative for this antigen. In contrast, HLA-DR3 positive recipients had the poorest outcome. Transplants from HLA-DRw6 positive donors showed higher transplant survival rates than donor kidneys positive for any other HLA-DR antigen. A correlation of transplant survival with HLA-B and DR mismatching was seen whether kidneys were collected within our region or received through the UK Transplant Service. We conclude that avoidance of mismatching for HLA-B and DR antigens confers high transplant survival rates (91.1% at 5 years for 0 HLA-B and DR mismatches), and in order to achieve this rate for most recipients exchange of donor kidneys between transplant centers will be essential.

Long-term follow-up of drusen-like lesions in patients with type II mesangiocapillary glomerulonephritis

Background: Drusen-like lesions beneath the retina in patients with partial lipodystrophy and type II mesangiocapillary glomerulonephritis (MCGN) were first reported in 1989. This study reports the long-term follow-up of this original cohort of patients more than 10 years later. Methods: Three patients had undergone renal transplantation. Retinopathy was graded semiquantitatively using an international classification and grading system. Progression was assessed by comparing the visual acuities and the colour, red-free and fluorescein angiographic photographs at baseline and review. Results: The visual acuity in all four patients was unchanged, as were the bilateral drusen-like lesions. The retinal pigment hypertrophy at the posterior pole of two of the patients was also unchanged. There were no signs of choroidal neovascularisation or central serous retinopathy in any patient. There was no progression of retinopathy over 10 years in any patient. Conclusion: This study suggests that in patients with type II MCGN, (a) factors other than drusen may contribute to choroidal neovascularisation and (b) renal transplantation does not appear to increase the risk of progression of retinopathy.

Twenty-one years survival with systemic AL-amyloidosis

AL-amyloidosis has a poor prognosis, typically with cardiac or renal failure ensuing some months after diagnosis. However, sporadically there have been reports of long-term survivors, either with unusual manifestations of amyloidosis, or after concerted chemotherapy to suppress the overt or occult pathological monoclonal plasma cell population responsible for the elaboration of immunoglobulin light chains. We report the case of a 46-year-old man who has survived 21 years after the histological diagnosis of renal amyloidosis was made, after he had presented with severe nephrotic syndrome. This patient was given intensive chemotherapy but came to end-stage renal failure some 10 years later, was dialysed for 1 year, and then was the successful recipient of a cadaveric renal transplant, which is working excellently some 10 years later, with little evidence of recurrent renal or systemic amyloidosis. There is renewed interest in therapy for systemic amyloidosis, and this case demonstrates that with this approach the prognosis can be more favorable than is commonly assumed.