K.S. Ozaki

Pregnancy after renal transplantation – a five-yr single-center experience

Abstract:  Background:  There has been an increase in the number of pregnancies in renal transplant recipients. Our aim was to report our experience with a significant casuistic.

Sequential cytomegalovirus antigenemia monitoring in kidney transplant patients treated with antilymphocyte antibodies

Abstract: Background: Antilymphocyte antibodies (ALA) use is related to disseminated cytomegalovirus (CMV) disease after kidney transplantation. Strict surveillance of CMV infection, preemptive antiviral treatment or concomitant ganciclovir and ALA use are proposed as an attempt to prevent related clinical complications. Our objective was to describe the pattern of CMV infection, based on sequential antigenemia detection, after ALA treatment.

Improved renal function after kidney transplantation is associated with heme oxygenase-1 polymorphism.

Abstract:  Heme oxygenase‐1 (HO‐1) has a microsatellite polymorphism based on the number of guanosine‐thymidine nucleotide repeats (GT) repeats that regulates expression levels and could have an impact on organ survival post‐injury. We correlated HO‐1 polymorphism with renal graft function. The HO‐1 gene was sequenced (N = 181), and the allelic repeats were divided into subclasses: short repeats (S) (<27 repeats) and long repeats (L) (≥27 repeats). A total of 47.5% of the donors carried the S allele. The allograft function was statistically improved six months, two and three yr after transplantation in patients receiving kidneys from donors with an S allele. For the recipients carrying the S allele (50.3%), the allograft function was also better throughout the follow‐up, but reached statistical significance only three yr after transplantation (p = 0.04). Considering only those patients who had chronic allograft nephropathy (CAN; 74 of 181), allograft function was also better in donors and in recipients carrying the S allele, two and three yr after transplantation (p = 0.03). Recipients of kidney transplantation from donors carrying the S allele presented better function even in the presence of CAN.

Effects of ischemia and reperfusion injury on long-term graft function.

BACKGROUND The clinical manifestation of ischemia/reperfusion injury in renal transplantation is delayed graft function (DGF), which is associated with an increase in acute rejection episodes (ARE), costs, and difficulties in immunosuppressive management. We sought to evaluated the DGF impact after renal transplant. METHODS We evaluated a group of 628 patients undergoing deceased donor renal transplantation between 2002 and 2005 at 3 Brazilians institutions to define the main DGF characteristics. RESULTS DGF incidence was 56.8%, being associated with elderly donors (P = .02), longer time on dialysis (P = .001), and greater cold ischemia time (CIT; P = .001). Upon multivariate analysis, time on dialysis >5 years increased DGF risk by 42% (P = .02) and CIT >24 hours increased it by 57% (P = .008). In contrast, DGF was associated with an higher incidence of ARE: 27.7% in DGF versus 18.4% in IGF patients (P = .047). The ARE risk was 46% higher among individuals with DGF (P = .02), 44% among patients >45 years old (P < .001), 50% among those with >5 years of dialysis time (P = .02), and 47% lower among the who were prescribed mycophenolate instead of azathioprine (P < .001). Patients with DGF showed worse 1-year graft function (54.6 ± 20.3 vs 59.6 ± 19.4 mL/min; P = .004), particularly those with ARE (55.5 ± 19.3 vs 60.7 ± 20.4; P = .009). One-year graft survival was 88.5% among DGF versus 94.0% among non-DGF patients. CONCLUSION The high incidence of DGF was mainly associated with a prolonged CIT. There was a relationship between DGF and ARE, as well as with a negative influence on long-term graft function.

Clinical correlations of human cytomegalovirus strains and viral load in kidney transplant recipients.

Little is known about clinical differences associated with cytomegalovirus (CMV) infection by distinct strains in renal transplant patients. Different clinical pictures may be associated with specific viral genotypes, viral load, as well as host factors. The objective of this study was to identify CMV strains to determine viral load (antigenemia), and their correlation with clinical data in renal transplant recipients. Seventy-one patients were enrolled, comprising 91 samples. After selection, polymorphonuclear cells were used to amplify and sequence the gB region of CMV DNA. The sequences were analyzed to ascertain the frequency of different genotypes. Additionally, the results of this study showed that the gB coding gene presents a great variability, revealing a variety of patterns: classical gB1 (1.4%), gB1V (46.4%), classical gB2 (35.2%), gB2V (2.8%), gB3 (1.4%), classical gB4 (4.9%) and gB4V (4.9%). The mean viral load in kidney transplant patient was 75.1 positive cells (1-1000). A higher viral load was observed in patients with genotype 4 infection. Statistically significant differences were detected between gB1 and gB4 (p=0.010), and between gB2 and gB4 (p=0.021). The average numbers of positive cells in relation to clinical presentation were: 34.5 in asymptomatic, 49.5 in CMV associated syndrome and 120.7 in patients with invasive disease (p=0.048). As a group, gB1 was the most frequent strain and revealed a potential risk for developing invasive disease. Viral load also seemed to be important as a marker associated with clinical presentation of the disease.

Prognostic factors associated with poor graft outcomes in renal recipients with post-transplant glomerulonephritis

Abstract:  Background:  Little data are available concerning post‐transplantation glomerulonephritis (PTx‐GN) and its prognostic factors associated with graft outcomes.

Expression of TLR-4 and -2 in peripheral mononuclear cells in renal transplant patients with TLR-4 gene polymorphism

INTRODUCTION TLR-4 has also been identified as a receptor for endogenous alarmins, which are increased post transplantation. TLR-4 has also been associated with a polymorphism that could impact graft outcome. OBJECTIVE To assess the expression of TLR-4 in kidney transplant patients carrying or not a polymorphism. METHODS TLR-4 polymorphism (A299G/T399I) was studied in 200 renal transplant patients. Healthy volunteers were also enrolled as control group. The polymorphism analysis was performed using restriction enzymes technique (RFLP). Functionality of TLR-4 polymorphism was assessed in samples from controls by quantification of TNF-α after LPS stimulus. TLR-4 and -2 expressions were also analyzed by flow cytometry. RESULTS TLR-4 polymorphism was present in 8.5% of renal transplant patients. This polymorphism was associated with impairment in TNF-α secretion. In general, in renal transplant patients, TLR-4 expression in monocytes and in neutrophils was lower than in health volunteers. TLR-2 and TLR-4 expressions in healthy volunteers with A299G/T399I TLR-4 polymorphism was higher than in wild-type genotype healthy volunteers (p<0.01 and p<0.05, respectively), and also higher than A299G/T399I TLR-4 polymorphism renal transplant patients (p<0.05). TLR-2 expression on neutrophils in wild-type genotype renal transplant patients was higher compared to wild-type genotype healthy volunteers, and was also higher in relation to A299G/T399I kidney transplanted patients (p<0.01). CONCLUSION Stable renal transplant patients with TLR-4 polymorphism have a lower expression of TLR-4 and TLR-2 receptors in peripheral mononuclear cells, which ultimately indicate a less responsiveness for alarmins.

Synergistic effect of mycophenolate mofetil and angiotensin-converting enzyme inhibitor in patients with chronic allograft nephropathy

Experimental data and few clinical non-randomized studies have shown that inhibition of the renin-angiotensin system by angiotensin-converting enzyme (ACE) associated or not with the use of mycophenolate mofetil (MMF) could delay or even halt the progression of chronic allograft nephropathy (CAN). In this retrospective historical study, we investigated whether ACE inhibition (ACEI) associated or not with the use of MMF has the same effect in humans as in experimental studies and what factors are associated with a clinical response. A total of 160 transplant patients with biopsy-proven CAN were enrolled. Eighty-one of them were on ACE therapy (G1) and 80 on ACEI_free therapy (G2). Patients were further stratified for the use of MMF. G1 patients showed a marked decrease in proteinuria and stabilized serum creatinine with time. Five-year graft survival after CAN diagnosis was more frequent in G1 (86.9 vs 67.7%; P < 0.05). In patients on ACEI-free therapy, the use of MMF was associated with better graft survival. The use of ACEI therapy protected 79% of the patients against graft loss (OR = 0.079, 95%CI = 0.015-0.426; P = 0.003). ACEI and MMF or the use of MMF alone after CAN diagnosis conferred protection against graft loss. This finding is well correlated with experimental studies in which ACEI and MMF interrupt the progression of chronic allograft dysfunction and injury. The use of ACEI alone or in combination with MMF significantly reduced proteinuria and stabilized serum creatinine, consequently improving renal allograft survival.

Are the current chronic allograft nephropathy grading systems sufficient to predict renal allograft survival

A major problem in renal transplantation is identifying a grading system that can predict long-term graft survival. The present study determined the extent to which the two existing grading systems (Banff 97 and chronic allograft damage index, CADI) correlate with each other and with graft loss. A total of 161 transplant patient biopsies with chronic allograft nephropathy (CAN) were studied. The samples were coded and evaluated blindly by two pathologists using the two grading systems. Logistic regression analyses were used to evaluate the best predictor index for renal allograft loss. Patients with higher Banff 97 and CADI scores had higher rates of graft loss. Moreover, these measures also correlated with worse renal function and higher proteinuria levels at the time of CAN diagnosis. Logistic regression analyses showed that the use of angiotensin-converting enzyme inhibitor (ACEI), hepatitis C virus (HCV), tubular atrophy, and the use of mycophenolate mofetil (MMF) were associated with graft loss in the CADI, while the use of ACEI, HCV, moderate interstitial fibrosis and tubular atrophy and the use of MMF were associated in the Banff 97 index. Although Banff 97 and CADI analyze different parameters in different renal compartments, only some isolated parameters correlated with graft loss. This suggests that we need to review the CAN grading systems in order to devise a system that includes all parameters able to predict long-term graft survival, including chronic glomerulopathy, glomerular sclerosis, vascular changes, and severity of chronic interstitial fibrosis and tubular atrophy.