Angiotensin-Converting Enzyme 2 in the Pathogenesis of Renal Abnormalities Observed in COVID-19 Patients

Coronavirus disease 2019 (COVID-19) was first reported in late December 2019 in Wuhan, China. The etiological agent of this disease is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the high transmissibility of the virus led to its rapid global spread and a major pandemic (ongoing at the time of writing this review). The clinical manifestations of COVID-19 can vary widely from non-evident or minor symptoms to severe acute respiratory syndrome and multi-organ damage, causing death. Acute kidney injury (AKI) has been recognized as a common complication of COVID-19 and in many cases, kidney replacement therapy (KRT) is required. The presence of kidney abnormalities on hospital admission and the development of AKI are related to a more severe presentation of COVID-19 with higher mortality rate. The high transmissibility and the broad spectrum of clinical manifestations of COVID-19 are in part due to the high affinity of SARS-CoV-2 for its receptor, angiotensin (Ang)-converting enzyme 2 (ACE2), which is widely expressed in human organs and is especially abundant in the kidneys. A debate on the role of ACE2 in the infectivity and pathogenesis of COVID-19 has emerged: Does the high expression of ACE2 promotes higher infectivity and more severe clinical manifestations or does the interaction of SARS-CoV-2 with ACE2 reduce the bioavailability of the enzyme, depleting its biological activity, which is closely related to two important physiological systems, the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS), thereby further contributing to pathogenesis. In this review, we discuss the dual role of ACE2 in the infectivity and pathogenesis of COVID-19, highlighting the effects of COVID-19-induced ACE2 depletion in the renal physiology and how it may lead to kidney injury. The ACE2 downstream regulation of KKS, that usually receives less attention, is discussed. Also, a detailed discussion on how the triad of symptoms (respiratory, inflammatory, and coagulation symptoms) of COVID-19 can indirectly promote renal injury is primary aborded.

Nonadherence to Immunosuppressive Medications Following Pediatric Kidney Transplantation Within Full Cost Coverage Health System: Prevalence and Correlates

OBJECTIVES

Pediatric patients are at higher risk of nonadherence to immunosuppressive medication after kidney transplant and the resulting adverse outcomes. Factors associated with nonadherence vary, which follow an epidemiological framework and according to health system patterns. The Brazilian public health system covers all costs of kidney transplant, including immunosuppressive medications. We aimed to assess the prevalence and correlates of nonadherence to immunosuppressive medications in a pediatric kidney transplant population who received free access to immunosuppressive medications within the health care system.

MATERIALS AND METHODS

In this single-center crosssectional study, we studied a convenience sample of 156 outpatients (< 18 years old) who were a minimum of 4 weeks posttransplant. Implementation nonadherence to immunosuppressive medications was measured by the 4 questions of the Basel Assessment of Adherence to Immunosuppressive Medications Scale. Multilevel correlates to non - adherence (patient, micro, and macro levels) were assessed.

RESULTS

In our patient population, 61% were males, mean age was 13.6 ± 3.1 years, 77% were adolescents, and 84% received organs from deceased donors. We found that 33% were nonadherent to immuno - suppressive medications, mainly in timing (25%) and taking (10.9%) dimensions. Being an adolescent (odds ratio: 2.66; CI, 1.02-6.96), religion other than Catholic or Protestant (odds ratio: 4.33; CI, 1.13-16.67), and family income higher than 4 reference wages (odds ratio: 3.50; CI, 1.14-10.75) were factors associated with nonadherence.

CONCLUSIONS

In our patient population of mostly adolescents, one-third displayed nonadherence to immunosuppressants. Unexpectedly, a higher economic profile, potentially representing better previous access to health care, was independently associated with nonadherence. This result highlights the need for identifying specific correlates to non - adherence before designing interventions.

Early Hospital Readmission (EHR) in kidney transplantation: a review article

Early hospital readmission (EHR), defined as all readmissions within 30 days of initial hospital discharge, is a health care quality measure. It is influenced by the demographic characteristics of the population at risk, the multidisciplinary approach for hospital discharge, the access, coverage, and comprehensiveness of the health care system, and reimbursement policies. EHR is associated with higher morbidity, mortality, and increased health care costs. Monitoring EHR enables the identification of hospital and outpatient healthcare weaknesses and the implementation of corrective interventions. Among kidney transplant recipients in the USA, EHR ranges between 18 and 47%, and is associated with one-year increased mortality and graft loss. One study in Brazil showed an incidence of 19.8% of EHR. The main causes of readmission were infections and surgical and metabolic complications. Strategies to reduce early hospital readmission are therefore essential and should consider the local factors, including socio-economic conditions, epidemiology and endemic diseases, and mobility.

Ureterocalicostomy with lower pole nephrectomy in a renal transplant: A case report

As the number of kidney transplants continues to rise, so does the number and complexities of surgical-related complications, which may be associated with increased morbidity and potentially graft loss. Ureteral stenosis, the most prevalent urological complication, may require diverse techniques for surgical correction depending on several recipient and graft abnormalities. Here we report the surgical and clinical outcomes of a 62-year-old man with a posttransplant pyeloureterostomy stricture successfully treated with ureterocalicostomy after a lower pole nephrectomy. Although the resection of renal parenchyma may prevent a stenosis recurrence, surgeons can be reluctant to use this strategy due to the possible negative impact on renal function. We highlight some key steps of the surgical technique to prevent unnecessary allograft lesion and present short-term outcomes, suggesting that this rarely described procedure is a safe and effective alternative treatment for kidney transplant recipients with pyeloureterostomy stenosis.

Is there relationship between epicardial fat and cardiovascular parameters in incident kidney transplant patients? A post-hoc analysis

Background

Epicardial fat (EF) has been related to increased cardiovascular risk in chronic kidney disease patients. Kidney transplantation is associated with weight gain, especially within the first 12 months. Recently an association between EF and left ventricular mass (LVM) has been suggested in kidney transplant (KTX) recipients.

Objective

Evaluate the EF in KTX recipients and its association with cardiovascular parameters in a 12-month follow-up study.

Methods

EF volume was determined using thoracic computed tomography. The EF progressor group (EF gain) was defined by any increment in EF after 12 months. LVM and LVM index were calculated by echocardiography.

Results

Ninety-eight incident KTX patients [57% men, 41.2 ± 10.1 years, mean dialysis time prior to transplant of 24 (11–60) months] were analyzed. At baseline and after 12 months, EF was 318.6 (275.2–392.6) ml and 329.5 (271.7–384.8) ml, respectively (p = 0.03). When compared to patients who EF decreased (n = 33), those with EF gain (n = 65) had a greater increase of body mass index, abdominal circumference and blood glucose. These patients also had a lower reduction of LVM index. However in the multivariate analysis, there was no difference in LVM index change between groups (interaction p = 0.565), even after adjustment for hypertension, glucose and coronary calcium score (interaction p = 0.538).

Conclusion

The impact of EF gain on ventricular mass after KTX could not be definitely confirmed. Further prospective studies in a large sample of KTX patients should be considered to address a possible causal relationship between EF gain and cardiac hypertrophy in this population.

Reviewing 15 years of experience with sirolimus

Here, we review 15 years of clinical use of sirolimus in our transplant center, in context with the developing immunosuppressive strategies use worldwide. The majority of studies were conducted in de novo kidney transplant recipients, using sirolimus (SRL) in combination with calcineurin inhibitors (CNIs). We also explored steroid (ST) or CNI-sparing therapies, including CNI minimization, elimination, or conversion strategies in combination with mycophenolate (MMF/MPS). Pooled long-term outcomes were comparable with those obtained with CNI and antimetabolite combination. Surprisingly, there are still several areas that need further investigation to improve the risk/benefit profile of SRL in kidney transplantation, including pharmacokinetic/pharmacodynamic drug-to-drug interaction with cyclosporine (CsA) or tacrolimus (TAC), mechanisms of SRL-associated adverse reactions and combinations with other drugs such as belatacept and once-daily TAC, possibly leading to improved long-term adherence. These studies, along with others investigating the benefits of SRL associated lower viral infections and malignancies, are essential as we do not expect the introduction of new immunosuppressive drugs in the near future.

Fatigue effects in daily life activities of kidney transplant recipients

After undergoing kidney transplantation, some patients still face one symptom that continues after the dialysis sessions: fatigue (physical and mental tiredness that does not get better after resting). Fatigue effects in the everyday lives of kidney transplant patients can be beneficially modified early by changing this scenario. This is a quantitative study about the intensity and impacts of fatigue in kidney transplant patients admitted to the Hypertension and Kidney Hospital from October 2011 to March 2012. The fatigue pictogram was used to evaluate the level of fatigue interference in the daily life activities of kidney transplant patients. The sample consists of 39 patients, and was developed in 2 phases: data collection and attendance after and before the transplantation until hospital discharge. Descriptive statistical analyses were used. In the group at issue, we have noticed the following profile of the sample: 84.3% of transplantations with live donors, most were men, average age 36.5 years old, average hospitalization time 11.1 days, average time of renal failure 66.4 months, systemic arterial hypertension prevalence 66.7%, and the prevalence of at least 1.8 diseases in each individual. The self-referred causes of chronic renal failure were uncontrolled systemic arterial hypertension, glomerulonephritis, and overuse of anti-inflammatory drugs, among others. The study shows that fatigue is directly related to the level of activities of daily living, causing less ability to perform activities in the higher level of fatigue, which is in the immediate postoperative period and only settling fully on the 9th postoperative day.

Planned randomized conversion from tacrolimus to sirolimus-based immunosuppressive regimen in de novo kidney transplant recipients

Planned conversion from tacrolimus to sirolimus was evaluated in de novo kidney transplant recipients. In this multicenter, randomized, open-label study, 297 patients were initially treated with tacrolimus, mycophenolate sodium and prednisone. Of the 283 patients reaching 3 months, 97 were converted to sirolimus (SRL), 107 were maintained on tacrolimus (TAC) and 79 were patients receiving TAC without criteria to undergo intervention at month 3 (TACex). The primary objective was to show superior estimated glomerular filtration rate (eGFR) in the SRL group at month 24. Of the 258 patients who completed 24 months, 91 (94%) were in the SRL group, 101 (94%) in the TAC group and 66 (84%) in the TACex group. In the intention-to-treat population there were no differences in eGFR (66.2 ± 25.3 vs. 70.7 ± 25.1, p = 0.817) or in the severity of chronic sclerosing lesions scores in 24-month protocol biopsies. Higher mean urinary protein-to-creatinine ratio (0.36 ± 0.69 vs. 0.15 ± 0.53, p = 0.03) and higher incidence of treated acute rejection between months 3-24 (13.4% vs. 4.7%, p = 0.047) were observed in SRL compared to TAC group. In this population planned conversion from TAC to SRL 3 months after kidney transplantation was not associated with improved renal function at 24 months.

Ventricular arrhythmia in incident kidney transplant recipients: prevalence and associated factors

Cardiovascular mortality in kidney transplant recipients has shown to be substantially elevated particularly in the first year of transplantation. Complex ventricular arrhythmia (VA) has been pointed as one of the etiologies of sudden death. The aim of this study was to evaluate the prevalence of VA and to investigate the factors associated with their occurrence in incident kidney transplant recipients. A total of 100 incident kidney transplant recipients were included in the study (39.7 ± 10.1 years, 55% male, 43.6 ± 10.1 days of transplantation, 66% living donors). All the patients underwent 24 h electrocardiogram, echocardiogram and multi-slice computed tomography. Thirty percent of the patients had VA. Left ventricular hypertrophy was observed in 57% of the patients while heart failure was found in 5%. Coronary artery calcification (CAC) was observed in 26 patients, from which 31% had severe calcification. The group of patients with VA was predominantly male, had been on dialysis therapy for a longer time and had more coronary calcification. In the multiple logistic regression analysis, male gender and CAC score were independently associated with the presence of VA. In conclusion, kidney transplant recipients exhibited a high prevalence of VA and the factors associated with its occurrence were the male gender and the presence of CAC.

Cystatin C and renal function in pediatric kidney transplant recipients

In clinical practice, the glomerular filtration rate (GFR) is often determined with serum creatinine. However, studies have shown cystatin C to be a better parameter for the diagnosis of impaired renal function. We compared GFR estimated by plasma cystatin C with GFR estimated by serum creatinine in a sample of 50 pediatric renal transplant recipients and 24 healthy children. The correlation between GFR estimated by serum creatinine and by cystatin C was significant (r = 0.75; P < 0.001, Person's correlation); however, in pediatric kidney transplant recipients, the GFR was 6.7 mL/min lower when determined using cystatin C rather than serum creatinine. Moreover, using GFR estimated by cystatin C we found that 42% of the pediatric kidney transplant recipients had an estimated GFR <60 mL.min-1.1.73 (m(2))-1, whereas when GFR was estimated by the serum creatinine formula only 16% of the children had values below this cutoff point indicative of chronic kidney disease (P < 0.001). We conclude that, in pediatric kidney transplant recipients, estimation of GFR yields lower values when cystatin C is used rather than serum creatinine.

Mini-incisions by lombotomy or subcostal access in living kidney donors: a randomized trial comparing pain, safety, and quality of life

OBJECTIVES

The aim of this study was to compare two mini-incision techniques and judge the impact on the quality of life, pain, and safety of living kidney donors.

PATIENTS AND METHODS

From March through September 2003, a prospective randomized study with 60 donors had nephrectomy performed - 30 through a lombotomy and another 30 patients underwent subcostal mini-incisions. The same anesthetic procedure was used for both groups. All patients were evaluated from baseline (T0) to day 90 after surgery. Pain evaluation included visual analog scale (VAS) and drug usage. To assess quality of life (QOL), the questionnaire SF-36 was used and surgical outcomes were also checked.

RESULTS

Sixty patients (41.6 +/- 8.9 yr old) were included in the protocol. Regarding incision length and blood loss, no statistical difference was observed. However, irrespective to the site of the mini-incision, patients with body mass index (BMI) higher than 25 kg/m(2) had significantly longer incision length as well as higher blood loss. There were no complications. No significant difference in tramadol or in pain perception was observed between groups. QOL was also not different between groups, however, there was a significant loss with subsequent return to baseline levels.

CONCLUSION

The position of the mini-incision (lombotomy or subcostal) has no significant impact on surgical outcomes, pain perception, and QOL of living kidney donors. Mini-incision techniques represent fast and safe approaches to perform nephrectomy in the healthy population. Special care must be taken in obese patients in order to minimize surgical complications.

Immunotherapy for De Novo Renal Transplantation

Immunosuppressive drugs have been traditionally developed to prevent acute rejection and to improve short-term kidney transplant outcomes. There is still a medical need to improve outcomes among subgroups of patients at higher risk for graft loss and to reduce cardiovascular, infectious and malignancy-associated morbidity and mortality, and improve long-term adherence. Several new immunosuppressive agents and formulations are undergoing clinical investigation and are discussed in this review.A modified release tacrolimus formulation (MR4) for once-daily administration is undergoing phase III trials. It has been developed to be administered de novo or for maintenance using the same therapeutic target tacrolimus trough concentrations as for the original formulation. Belatacept (LEA29Y), a second generation cytotoxic-T-lymphocyte-associated antigen immunoglobulin (CTLA4-Ig), blocks the interaction between CD80/86 and CD28 costimulatory pathways. In phase II trials, belatacept was as effective as ciclosporin (cyclosporine) when administered in combination with basiliximab, mycophenolate mofetil (MMF) and corticosteroids. Currently, belatacept is undergoing phase III trials including one study in recipients of organs from expanded criteria donors. Inhibitors of the Janus protein tyrosine kinase (JAK)-3 show some selectivity for cells of the lymphoid lineage and have been shown to be effective in late preclinical transplant models. The most frequent adverse effects have been related to nonspecific binding to JAK2 kinases. CP-690550, a JAK3 inhibitor is currently in phase II clinical trials.FK778, is a synthetic malononitrilamide that targets the critical enzyme of the de novo pyrimidine synthesis, dihydroorotic acid dehydrogenase, and receptor-associated tyrosine kinases has completed phase II trials. FK778 also shows antiviral activities that have been tested in patients with polyomavirus nephropathy. Fingolimod (FTY720), a synthetic sphingosine phosphate receptor modulator that reduces the recirculation of lymphocytes to blood and peripheral tissues including inflammatory lesions and graft sites is undergoing phase III trials. Although the efficacy of fingolimod is similar to MMF in patients receiving full doses of ciclosporin, safety issues such as a negative chronotropic effect, macular oedema, pulmonary adverse reactions and graft function resulted in premature discontinuation of the development programme for kidney transplantation. Because there was no clear clinical benefit over treatment options, the clinical development programme of FK778 was discontinued.Finally, a new evolving strategy with powerful induction-induced prolonged T-cell depletion followed by low-dose immunosuppressive monotherapy is showing promising results.

FTY720 impairs necrosis development after ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury is a common early feature that contributes to graft damage by impairing resident cell function. Our previous results showed that IR injury impaired renal function, by causing extensive tubular necrosis and increasing MHC class II and ICAM-1 molecule expression by mesangial cells (MC). MCs are likely candidates to come into close contact with immune cells such as monocytes or lymphocytes. It has been suggested that under inflammatory circumstances, there is increased MC expression of MHC class II, of adhesion molecules (such as ICAM-1), of cytokines receptors, and of molecules associated with cellular death (apoptosis). The immunosuppressive properties of FTY720 have been shown in clinical and experimental situations. It has also been shown to be protective against IR injury in rats. We sought to evaluate the role of FTY720 in a murine IR model by measuring renal function, tubular necrosis, and surface molecule expression by cultured mesangial cells. Intravenous administration of FTY720 (1 mg/kg) immediately before IR induction did not improve the short-term (24 hours) outcome of renal function or reduced MHC class II and ICAM-1 surface molecule expression. However, there was a decreased percentage of tubular necrosis in mice treated with FTY720 (51.3% +/- 1.6%) compared with vehicle-treated mice (66% +/- 5.5%). These results suggest a protective role of FTY720 in an IR injury model. More studies are required to identify the mechanisms involved in the protective activity of FTY720 in the IR injury model.

FTY720 prevents renal T-cell infiltration after ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury, a common early feature in renal transplantation, results from both free radical species generation and local inflammatory responses that attract different types of cells. The interaction with infiltrating leukocytes could promote damage and death of resident renal cells contributing to worsening of renal function. It has been shown that depletion of host T cells protects against kidney damage after I/R injury, although the mechanism is not fully understood. FTY720, a synthetic analog of a natural product extracted from Isaria sincclairii has shown modulatory properties in experimental models of autoimmune disease, transplantation, and I/R injury. FTY720 alters lymphocyte responses to chemokine homing signals, thereby decreasing the number of lymphocytes in inflammatory sites. We evaluated renal function in mice at 3, 5, and 7 days after I/R injury in the presence or absence of FTY720 treatment. FTY720 treatment promoted earlier recovery of renal function associated with a lower number of renal-infiltrating lymphocytes. These findings confirm previous results showing a protective effect of FTY720 in I/R injury models.

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

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.

PATIENTS AND METHODS

Thirty renal transplant patients were prospectively screened for CMV infection after ALA treatment. CMV antigenemia (pp65 antigen detection) was monitored twice a week in the first month and weekly until 60 days after the beginning of ALA therapy. Any positive value of antigenemia was considered CMV infection.

RESULTS

Twenty-eight (93.3%) patients were CMV positive (IgG) before transplantation. The mean duration of ALA treatment was 12.1+/-2.4 days. Positive antigenemia was detected in 24 (80%) patients, a mean of 52.5+/-15 days after transplant and 44.7+/-14 days after the beginning of ALA treatment. The median antigenemia count was 7 positive cells/300,000 neutrophils (range: 1-227). Antigenemia preceded clinical symptoms by 5.8 days (0-28 days). Eighteen (75%) of 24 positive patients received ganciclovir treatment: 8 patients (26.7%) for viral syndrome, 2 patients (33.3%) for invasive disease, and 8 patients (26.7%) as part of preemptive therapy, asymptomatic with high antigenemia values. Six pp65-positive patients with low counts were followed up until a negative result and remained asymptomatic without any specific treatment.

CONCLUSION

CMV infection was frequent after ALA treatment in this group and generally occurred late after completion of treatment. Antigenemia was a reliable tool to guide preemptive treatment in these patients, and such strategy is an alternative option compared to the prophylactic use of ganciclovir with ALA treatment.

Prevalence of previous hepatitis A virus infection in renal transplant patients with hepatitis C: evidence of persistent anti-hepatitis A virus immune response

Data concerning the prevalence of hepatitis A virus (HAV) infection among kidney transplant recipients are scarce. There is little information concerning natural immunity acquired after acute HAV infection. In most renal transplant recipients, anti-HAV antibodies are not detectable after vaccination; it is reasonable to suppose that immunosuppressive therapy interferes with the immunity. The objective of this study was to evaluate, in an endemic area, the prevalence of anti-HAV immunoglobulin (Ig)G in renal transplant recipients with chronic hepatitis C virus (HCV) infection. The prevalence of anti-HAV IgG was assessed in 40 HCV-positive renal transplant recipients. This group showed a 90% prevalence of previous HAV infection. These findings suggest that in an endemic area, the prevalence of previous HAV infection is high, even among immunosuppressed patients. HAV antibodies acquired after natural infection are detectable even after the onset of immunosuppressive therapy. These data should be considered when renal transplant recipients are considered for HAV vaccination. Prevaccination screening of renal transplant recipients must follow the same guidelines as those for immunocompetent subjects.

Do we need living unrelated organ donation in Brazil?

The remarkable success achieved by organ transplantation has also engendered the major problem of organ shortage. As a consequence, the use of living unrelated donors (LURD) has been proposed as an ethically justifiable alternative for developed nations to minimize their waiting lists for organ transplantation (OTx). This change in attitude has caused an ethical dilemma for developing countries like Brazil, which is struggling to increase the cadaver donor pool. Due to a huge socioeconomic gap of values and needs among nations, the incentive to use LURD in developed countries may not only produce a disincentive to cadaver organ donation but also stimulate organ trade in developing countries. In this paper we aimed to show that in Brazil, we do not need to use LURD because we have not optimized our cadaver donor pool. The exploitation of LURD might be a good option for developed countries, but it is not useful for developing countries. The Transplantation Society urgently needs to solve and clarify this problem by establishing basic ethical and justice principles that can serve as a guide for every country, throughout the entire process required, to achieve an adequate pool of cadaver donors.

Expanding criteria for the use of living donors: what are the limits?

The cadaver organ shortage has pushed the transplant community to extend the boundaries beyond the traditional criteria used for living donor transplantation. This new liberal policy involves: (1) the type of donor, such as emotionally related individuals, the direct or indirect interchange of donors, anonymous as well as rewarded donation; (2) challenging immunological criteria, using incompatible ABO blood types and or transplantation across a positive cross-match; (3) relaxing clinical criteria related to elderly, hypertensive, or obese donors, or patients with nephrolithiasis, fibromuscular renal artery disease, hematuria, or renal cell carcinomas. However, these practices may be dangerous. They must be clearly validated to promote a liberal policy of donor acceptance since it may carry a risk for both the donor and the recipient as well as for society. It is crucial to ensure the physical integrity of the donor as well as to provide guarantees, for instance a 1-year policy of life insurance, an indefinite long-term medical follow-up and the assurance of going to the top of the waiting list if the donor becomes uremic in the future.

FTY720 treatment prolongs skin graft survival in a completely incompatible strain combination

FTY720 has shown potent immunomodulatory activity in a variety of animal organ transplant models. However, the in vivo immunosuppressive mechanism of FTY720 is still not fully understood. It has been suggested that the marked decrease in the number of peripheral blood lymphocytes during FTY720 administration could be responsible for its immunosuppressive effects. Our aims were: (1) to study the effects of FTY720 treatment on skin graft survival using a fully mismatched strain combination and (2) to evaluate lymphocyte numbers in different sites at 5 days after skin transplant. C57BL/6 mice and BALB/c mice were the donors and recipients respectively. BALB/c mice received FTY720 (1 mg/kg/d) orally for 4 consecutive days. Drug administration started 1 day before skin transplants. A small segment of tail skin was affixed on the right dorsal side of the mouse via sutures. The administration of FTY720 (4 mg/kg) prolonged skin graft survival from 12.6 +/- 2.2 days (no treatment) to 16.6 +/- 4.2 days. The histologic findings of rejection were similar for all groups. Five days after transplant, lymphocyte numbers were significantly increased in lymph nodes compared with nontransplanted or isogenic graft mice. FTY720 decreased lymphocyte numbers only in the spleen. In conclusion, FTY720 prolonged skin graft survival in a fully mismatched strain combination when administered for 4 days (day -1 to day +2) at a dose of 1 mg/kg/d. The decreased number of lymphocytes in the spleen suggests that the spleen may be a target of FTY720 activity, during the early posttransplant period.

Risk factors for the development of posttransplantation diabetes mellitus in simultaneous pancreas and kidney recipients

We sought to determine the risk factors involved in the development of posttransplantation diabetes mellitus (PTDM) following simultaneous pancreas and kidney transplantation. Correlations were sought between tacrolimus (FK-506) levels/dose 2-hour capillary glucose (CG) and glycosylated hemoglobin (HbA(1c)), cyclosporine (CSA) levels/dose with HbA1c, 2-hour CG with prednisone dose and body mass index (BMI) and PTDM. Four patients (9.3%) developed PTDM. Three treated with FK-506 had altered 2-hour CG at 3 months after transplantation; 1 prescribed CSA displayed diabetes diagnosed after 1 year. There was no statistically significant difference among HbA(1c) values and FK-506 (P =.18) or CSA (P =.81) doses or FK-506 (P =.53) and CSA (P =.54) levels. In contrast, there was a statistically significant relationship between elevated 2-hour CG (> or =200 mg/dL) and daily prednisone dose (9.7 mg vs. 16.2 mg; P =.003). There was no correlation between 2-hour CG and FK-506 dose (P =.084) or FK-506 levels (P =.075). The greater BMI correlated with an increased risk of PTDM (21.25 +/- 3.13 kg/m(2) vs 24.67 +/- 2.38 kg/m(2); P =.034). Two-hour CG may be a useful tool to screen the diabetogenic effects of corticosteroids. A BMI increase should be discouraged due to the risk of PTDM.

Simultaneous pancreas-kidney transplantation: infectious complications and microbiological aspects

OBJECTIVE

The purpose of this study was to describe the clinical and microbiological characteristics of the infectious complications among simultaneous pancreas-kidney transplantations (SPKT).

MATERIALS AND METHODS

Among the first 45 SPKT the mean age was 34 years (range, 21 to 49) and the mean duration of follow-up 13 months (range, 2 to 27 months).

RESULTS

Twenty-three patients (51%) presented at least one to three episodes (1.7 mean) of infectious complications that needed hospitalization. The etiology of the infections included 71% bacterial (44% gram-negative rods and 27% gram-positive cocci), 16% viral (12% from CMV and 4% from Herpes sp) and 13% fungal (8% by Candida sp and 4% by others fungus). Wound and urinary infections were most frequent, occurring in 22% and 28% of the patients, respectively. All patients who were submitted to vesical drainage developed infections in contrast a rate of only 44% among patients undergoing enteric drainage.

CONCLUSION

Infectious complications are the main cause of morbidity and mortality following simultaneous pancreas-kidney transplantation, especially with vesical drainage. The use of enteric drainage combined with administration of broad spectrum prophylactic antibiotics is recommended.

The role of CD8+ T cells during allograft rejection

Organ transplantation can be considered as replacement therapy for patients with end-stage organ failure. The percent of one-year allograft survival has increased due, among other factors, to a better understanding of the rejection process and new immunosuppressive drugs. Immunosuppressive therapy used in transplantation prevents activation and proliferation of alloreactive T lymphocytes, although not fully preventing chronic rejection. Recognition by recipient T cells of alloantigens expressed by donor tissues initiates immune destruction of allogeneic transplants. However, there is controversy concerning the relative contribution of CD4+ and CD8+ T cells to allograft rejection. Some animal models indicate that there is an absolute requirement for CD4+ T cells in allogeneic rejection, whereas in others CD4-depleted mice reject certain types of allografts. Moreover, there is evidence that CD8+ T cells are more resistant to immunotherapy and tolerance induction protocols. An intense focal infiltration of mainly CD8+CTLA4+ T lymphocytes during kidney rejection has been described in patients. This suggests that CD8+ T cells could escape from immunosuppression and participate in the rejection process. Our group is primarily interested in the immune mechanisms involved in allograft rejection. Thus, we believe that a better understanding of the role of CD8+ T cells in allograft rejection could indicate new targets for immunotherapy in transplantation. Therefore, the objective of the present review was to focus on the role of the CD8+ T cell population in the rejection of allogeneic tissue.