Fabiana Agena

Preserving the B-Cell Compartment Favors Operational Tolerance in Human Renal Transplantation

Transplanted individuals in operational tolerance (OT) maintain long-term stable graft function after completely stopping immunosuppression. Understanding the mechanisms involved in OT can provide valuable information about pathways to human transplantation tolerance. Here we report that operationally tolerant individuals display quantitative and functional preservation of the B-cell compartment in renal transplantation. OT exhibited normal numbers of circulating total B cells, naive, memory and regulatory B cells (Bregs) as well as preserved B-cell receptor repertoire, similar to healthy individuals. In addition, OT also displayed conserved capacity to activate the cluster of differentiation 40 (CD40)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in Bregs, in contrast, with chronic rejection. Rather than expansion or higher activation, we show that the preservation of the B-cell compartment favors OT.

The dynamics of glucose metabolism under calcineurin inhibitors in the first year after renal transplantation in nonobese patients

Background. The incidence of glucose metabolism disturbances after transplantation often is based on the use of hypoglycemic agents and not on the results of glucose tolerance tests (GTTs), which may camouflage the real incidence. A lack of information also exists regarding the profile of glucose metabolism during the first year after transplant. Methods. Oral GTT along with insulin measurements and drugs pharmacokinetics were prospectively performed at days 30, 60, 180, and 360 after transplant to diagnose disturbances of glucose metabolism after renal transplantation, in nonobese patients receiving either tacrolimus (n=55) or cyclosporine (n=29), along with mycophenolate mofetil and steroids. Results. The incidence of impaired glucose tolerance or diabetes mellitus reached a peak at 60 days and decreased at 1 year. It could not be adequately diagnosed using fasting plasma glucose in a decreased abnormal (>99 ng/mL) range. In both groups, insulin secretion, evaluated by the Homeostasis Model Assesment (HoMA-β), decreased (P<0.005) from the condition of normal GTT (101±56%) to impaired glucose tolerance (72±35%) and diabetes mellitus (54±25%). In the cyclosporine group, insulin secretion was normal and stable throughout the study period, but in the tacrolimus group, insulin secretion recovered over time and was inversely correlated with tacrolimus exposure. Insulin resistance (HoMA-IR) did not change. Conclusions. This study shows the need to perform an oral GTT at 60 days and at the end of the first year of renal transplantation to adequately diagnose impaired glucose metabolism.

A MULTI-FACTORIAL BIOLOGICAL MODULATION PROTOCOL THAT AMELIORATES ISCHEMIA-REPERFUSION INJURY SIMULTANEOUSLY REDUCES BILESALT TOXICITY IN PORCINE LIVER TRANSPLANTATION FROM NON-HEART BEATING DONORS

Plasma clearance of 51Cr‐EDTA (51Cr‐EDTA‐Cl) is an alternative method to evaluate glomerular filtration rate (GFR). This study aimed to investigate the concordance between 51Cr‐EDTA‐Cl and renal inulin clearance (In‐Cl) in renal transplant recipients as well to determine the repeatability of 51Cr‐EDTA‐Cl in kidney donors. Forty four kidney recipients and 22 kidney donors were enrolled. Simultaneous measurements of 51Cr‐EDTA‐Cl and In‐Cl were performed. A single dose of 3.7MBq of 51Cr‐EDTA was injected and the plasma disappearance curve was created by taking blood samples at 2, 4, 6 and 8 h after injection. Bland and Altman statistical approach was used to quantify the agreement between In‐Cl and 51Cr‐EDTA‐Cl and to determine the better concordance between all possibilities of measure for the 51Cr‐EDTA‐Cl. The mean of In‐Cl was 44.5 ± 17.9 ml/min/1.73 m2. There was a positive correlation between In‐Cl and all possible measurements of 51Cr‐EDTA‐Cl. 51Cr‐EDTA‐Cl with two samples taken at 4 and 8 h or at 4 and 6 h presenting the narrow limits of agreement and a difference (bias) of 2.8 and 2.7 ml/min, respectively. Two plasma sampling for 51Cr‐EDTA‐Cl was a reliable method to measure GFR compared with In‐Cl and comprises a suitable method to be used in kidney transplanted patients.

Home blood pressure (BP) monitoring in kidney transplant recipients is more adequate to monitor BP than office BP

BACKGROUND Hypertension is highly prevalent among kidney transplantation recipients and considered as an important cardiovascular risk factor influencing patient survival and kidney graft survival. Aim. Compare the blood pressure (BP) control in kidney transplant patients through the use of home blood pressure monitoring (HBPM) is more comparable with the results of ambulatory blood pressure monitoring compared to the measurement of office blood pressure. METHODS From March 2008 to April 2009 prospectively were evaluated 183 kidney transplant recipients with time after transplantation between 1 and 10 years. Patients underwent three methods for measuring BP: office blood pressure measurement (oBP), HBPM and ambulatory blood pressure monitoring (ABPM). RESULTS In total, 183 patients were evaluated, among them 94 were men (54%) and 89 women (46%). The average age was 50 ± 11 years. The average time of transplant was 57 ± 32 months. Ninety-nine patients received grafts from deceased donors (54%) and 84 were recipients of living donors (46%). When assessed using oBP, 56.3% presented with uncontrolled and 43.7% with adequate control of BP with an average of 138.9/82.3 ± 17.8/12.1 mmHg. However, when measured by HBPM, 55.2% of subjects were controlled and 44.8% presented with uncontrolled BP with an average of 131.1/78.5 ± 17.4/8.9 mmHg. Using the ABPM, we observed that 63.9% of subjects were controlled and 36.1% of patients presented uncontrolled BP with an average 128.8/80.5 ± 12.5/8.1 mmHg. We found that the two methods (oBP and HBPM) have a significant agreement, but the HBPM has a higher agreement that oBP, confirmed P = 0.026. We found that there is no symmetry in the data for both methods with McNemar test. The correlation index of Pearson linear methods for the ABPM with the other two methods were 0.494 for office measurement and 0.768 for HBPM, best value of HBPM with ABPM. Comparing the errors of the two methods by paired t-test, we obtained the descriptive level of 0.837. Looking at the receiver operating characteristic curve for BP measurements in each method, we observed that oBP is lower than those obtained by HBPM in relation to ABPM. CONCLUSION We conclude that the results obtained with HBPM were closer to the ABPM results than those obtained with BP obtained at oBP, being more sensitive to detect poor control of hypertension in renal transplant recipients.

The impact of pretransplant donor-specific antibodies on graft outcome in renal transplantation: a six-year follow-up study

OBJECTIVE: The significance of pretransplant, donor-specific antibodies on long-term patient outcomes is a subject of debate. This study evaluated the impact and the presence or absence of donor-specific antibodies after kidney transplantation on short- and long-term graft outcomes. METHODS: We analyzed the frequency and dynamics of pretransplant donor-specific antibodies following renal transplantation from a randomized trial that was conducted from 2002 to 2004 and correlated these findings with patient outcomes through 2009. Transplants were performed against a complement-dependent T- and B-negative crossmatch. Pre- and posttransplant sera were available from 94 of the 118 patients (80%). Antibodies were detected using a solid-phase (Luminex®), single-bead assay, and all tests were performed simultaneously. RESULTS: Sixteen patients exhibited pretransplant donor-specific antibodies, but only 3 of these patients (19%) developed antibody-mediated rejection and 2 of them experienced early graft losses. Excluding these 2 losses, 6 of 14 patients exhibited donor-specific antibodies at the final follow-up exam, whereas 8 of these patients (57%) exhibited complete clearance of the donor-specific antibodies. Five other patients developed “de novo” posttransplant donor-specific antibodies. Death-censored graft survival was similar in patients with pretransplant donor-specific and non-donor-specific antibodies after a mean follow-up period of 70 months. CONCLUSION: Pretransplant donor-specific antibodies with a negative complement-dependent cytotoxicity crossmatch are associated with a risk for the development of antibody-mediated rejection, although survival rates are similar when patients transpose the first months after receiving the graft. Our data also suggest that early posttransplant donor-specific antibody monitoring should increase knowledge of antibody dynamics and their impact on long-term graft outcome.

A Double-Blinded, Prospective Study to Define Antigenemia and Quantitative Real-Time Polymerase Chain Reaction Cutoffs to Start Preemptive Therapy in Low-Risk, Seropositive, Renal Transplanted Recipients

Background Cytomegalovirus (CMV) disease occurs in 16% to 20% of low-risk, CMV-positive renal transplant recipients. The cutoffs for quantitative real-time polymerase chain reaction (qPCR) or phosphoprotein (pp65) antigenemia (pp65emia) for starting preemptive therapy have not been well established. Methods We measured qPCR and pp65emia weekly from day 7 to day 120 after transplantation, in anti-CMV immunoglobulin G–positive donor and recipient pairs. Patients and physicians were blinded to the test results. Suspicion of CMV disease led to the order of new tests. In asymptomatic viremic patients, the highest pp65emia and qPCR values were used, whereas we considered the last value before diagnosis in those with CMV disease. Results We collected a total of 1,481 blood samples from 102 adult patients. Seventeen patients developed CMV disease, 54 presented at least one episode of viremia that cleared spontaneously, and 31 never presented viremia. Five patients developed CMV disease after the end of the study period. The median (95% confidence interval) pp65emia and qPCR values were higher before CMV disease than during asymptomatic viremia (6 [9–82] vs. 3 [1–14] cells/106 cells; P<0.001 and 3,080 [1,263–15,605] vs. 258 [258–1,679] copies/mL; P=0.008, respectively). The receiver operating characteristic curve showed that pp65emia 4 cells/106 cells or greater showed a sensitivity and specificity to predict CMV disease of 69% and 81%, respectively (area, 0.769; P=0.001), with a positive predictive value of 37% and a negative predictive value of 93%. For qPCR 2,000 copies/mL or higher, the positive predictive value and negative predictive value were 57% and 91%, respectively (receiver operating characteristic area, 0.782; P=0.000). Conclusion With these cutoffs, both methods are appropriate for detecting CMV disease.

Dynamics of anti-human leukocyte antigen antibodies after renal transplantation and their impact on graft outcome.

The purpose of this study was to sequentially monitor anti‐HLA antibodies and correlate the results with antibody‐mediated rejection (AMR), graft survival (GS), and graft function (GF). We collected sera from 111 kidney transplant recipients on transplant days 0, 7, 14, 30, 60, 90, 180, and 360 and analyzed PRA levels by ELISA. DSAs were analyzed by single‐antigen beads in rejecting kidneys. At pre‐transplant, 79.3% of the patients were non‐sensitized (PRA = 0%) and 20.7% were sensitized (PRA > 1%). After transplant, patients were grouped by PRA profile: no anti‐HLA antibodies pre‐ or post‐transplant (group HLApre−/post−; n = 80); de novo anti‐HLA antibodies post‐transplant (group HLApre−/post+; n = 8); sensitized pre‐transplant/increased PRA post‐transplant (group HLApre+/post↑; n = 9); and sensitized pre‐transplant/decreased PRA post‐transplant (group HLApre+/post↓; n = 14). De novo anti‐HLA antibodies were detected at 7–180 d. In sensitized patients, PRA levels changed within the first 30 d post‐transplant. Incidence of AMR was higher in HLApre−/post+ and HLApre+/post↑ than in HLApre−/post−, and HLApre+/post↓ (p < 0.001) groups. One‐yr death‐censored GS was 36% in group HLApre+/post↑, compared with 98%, 88% and 100% in groups HLApre−/post−, HLApre−/post+, and HLApre+/post↓, respectively (p < 0.001). Excluding first‐year graft losses, GF and GS were similar among the groups. In conclusion, post‐transplant antibody monitoring can identify recipients at higher risk of AMR.

Seroconversion of 2009 pandemic influenza A (H1N1) vaccination in kidney transplant patients and the influence of different risk factors

Influenza may present a high morbidity and mortality in solid organ transplanted patients (SOTP). Annual influenza virus vaccine is recommended for SOTP. However, low levels of seroconversion in SOTP have been reported. The aim of this study was to evaluate the immunogenicity of 2009 pandemic influenza A (H1N1) – A(H1N1)pdm09 – vaccine in kidney transplant patients and to analyze which features might affect seroconversion.

Diminished mycophenolic acid exposure caused by omeprazole may be clinically relevant in the first week posttransplantation.

Background: Some studies have reported a decreased absorption of mycophenolic acid (MPA) from mycophenolate mofetil (MMF) in renal transplanted (RTx) patients under proton-pump inhibitors (PPIs). There is still a lack of information regarding (1) whether this effect occurs when MMF is administered with either tacrolimus or cyclosporine A [calcineurin inhibitors (CNIs)], (2) whether the effect has the same amplitude during the first year after RTx, and finally (3) whether this decrease in exposure is clinically relevant. Methods: We retrospectively analyzed the omeprazole effect in 348 12-hour pharmacokinetic samplings [area under the curve (AUC)0–12h] performed on days 7, 14, 30, 60, 180, and 360 after RTx in 77 patients who participated in previous trials. Results: For all periods, the groups with and without PPI did not differ in all variables. By mixed-model analysis of variance, PPI reduced the MPA AUC0–12h (P < 0.0008) in the patients under both CNIs mainly due to decreased absorption (P = 0.049). In the tacrolimus group, a lower exposure seemed also due to a decreased MPA reabsorption at 10–12 hours. The PPI effect remains throughout the first year but was clinically more important on day 7. By Cox analysis, the use of PPI was associated with a 25% less chance of being adequately exposed to MPA (95% confidence interval 0.58–0.99, P = 0.04). Similarly, the number of patients underexposed to MPA (AUC < 30 ng·h/mL) was higher at most periods in the PPI group but again not statistically significant. Conclusions: These data indicate that PPI decreases the MPA exposure when associated with both CNIs but particularly in the first week after RTx. In this period, the MMF dose should be increased. This effect lasts throughout the first year but does not seem to be clinically relevant after the first week.

Monitorização residencial da pressão arterial: atualidades e papel do enfermeiro

Trata-se de um artigo de revisao sobre o assunto monitorizacao residencial da pressao arterial (MRPA) com o objetivo de agregar a contribuicao cientifica atual e apresentar a relevância desta abordagem na assistencia ao paciente hipertenso em nosso meio. A tecnica oferece vantagens em relacao a medida casual, pois proporciona um maior numero de medidas, melhor relacao com lesao de orgaos-alvo, quantifica o efeito do avental branco, possui boa reprodutibilidade, boa aceitabilidade pelos pacientes, proporciona avaliacao da pressao sem a influencia do observador e do ambiente do consultorio, diminui o numero de visitas ao consultorio e promove maior adesao ao tratamento. A importância da atuacao do profissional enfermeiro na MRPA esta ligada ao processo de educacao, utilizando estrategias de ensino-aprendizagem, implementando a comunicacao equipe-paciente e motivando o paciente a realizar o autocuidado.This is a review article on home blood pressure monitoring (HBPM) developed with the purpose to increase the current scientific knowledge and present the importance of this approach in the care to patients with hypertension in our setting. This technique has advantages over the causal measurement, as it provides more measurements, a better relationship with the target-organs injuries, it also quantifies the white-coat effect, has good reproducibility, good acceptability by the patients, assesses blood pressure without the influence from the observer and the environment of the appointment, reduces the number of visits to the doctor and promotes greater adherence to treatment. The importance of nursing practice in HBPM is associated with the education process, using teaching-learning strategies, implementing team-patient communication and encouraging patients towards performing self-care.