The natural history of clinical operational tolerance after kidney transplantation through twenty-seven cases

We report here on a European cohort of 27 kidney transplant recipients displaying operational tolerance, compared to two cohorts of matched kidney transplant recipients under immunosuppression and patients who stopped immunosuppressive drugs and presented with rejection. We report that a lower proportion of operationally tolerant patients received induction therapy (52% without induction therapy vs. 78.3%[p = 0.0455] and 96.7%[p = 0.0001], respectively), a difference likely due to the higher proportion (18.5%) of HLA matched recipients in the tolerant cohort. These patients were also significantly older at the time of transplantation (p = 0.0211) and immunosuppression withdrawal (p = 0.0002) than recipients who rejected their graft after weaning. Finally, these patients were at lower risk of infectious disease. Among the 27 patients defined as operationally tolerant at the time of inclusion, 19 still display stable graft function (mean 9 ± 4 years after transplantation) whereas 30% presented slow deterioration of graft function. Six of these patients tested positive for pre-graft anti-HLA antibodies. Biopsy histology studies revealed an active immunologically driven mechanism for half of them, associated with DSA in the absence of C4d. This study suggests that operational tolerance can persist as a robust phenomenon, although eventual graft loss does occur in some patients, particularly in the setting of donor-specific alloantibody.

Rapid T cell repopulation after rabbit anti-thymocyte globulin (rATG) treatment is driven mainly by cytomegalovirus

Rabbit anti-thymocyte globulin (rATG) induces a long-lasting lymphocytopenia. CD4(+) T cells remain depleted for up to 2 years, whereas the CD8(+) T cell compartment is refilled rapidly by highly differentiated CD27(-) CD45RA(+) CD57(+) effector-type cells. Because the presence of these highly differentiated CD8(+) T cells has been associated with cytomegalovirus (CMV) infection, we questioned to what extent restoration of CMV T cell immunity contributes to the re-emergence of T cells following rATG treatment. We compared T cell repopulation in six CMV-seropositive patients with CMV reactivation (reactivating CMV(+) ) to that in three CMV(+) patients without reactivation (non-reactivating CMV(+) ), and to that in three CMV-seronegative recipients receiving a kidney from a CMV-seronegative donor (CMV(-/-) ). All patients received rATG because of acute allograft rejection. Total CD4 and CD8 counts, frequency and phenotype of virus-specific CD8(+) T cells were determined. In reactivating CMV(+) patients, total CD8(+) T cells reappeared rapidly, whereas in non-reactivating CMV(+) patients they lagged behind. In CMV(-/-) patients, CD8(+) T cell counts had not yet reached pretransplant levels after 2 years. CMV reactivation was indeed followed by a progressive accumulation of CMV-specific CD8(+) T cells. During lymphocytopenia following rATG treatment, serum interleukin (IL)-7 levels were elevated. Although this was most prominent in the CMV-seronegative patients, it did not result in an advantage in T cell repopulation in these patients. Repopulated CD8(+) T cells showed increased skewing in their Vβ repertoire in both CMV(-/-) and reactivating CMV-seropositive patients. We conclude that rapid T cell repopulation following rATG treatment is driven mainly by CMV.

Viral double-stranded RNA sensors induce antiviral, pro-inflammatory, and pro-apoptotic responses in human renal tubular epithelial cells

Viral infection in the kidney is characterized by tubular injury induced directly by the virus and/or by cytotoxic lymphocytes. Previously, we found that human tubular epithelial cells express Toll-like receptor 3 (TLR3), melanoma differentiation-associated gene 5 (MDA5), and retinoic acid-inducible gene-I (RIG-I), all sensors of double-stranded RNA (dsRNA) and potent inducers of antiviral activity. Here, we demonstrate increased expression of these three dsRNA sensors in kidney transplant biopsies during cytomegalovirus or BK virus infection. In primary tubular epithelial cells, dsRNA sensor activation induced the production of pro-inflammatory TNF-α and antiviral IFN-β. Notably, dsRNA also enhanced the expression of pro-apoptotic proteins; however, dsRNA alone did not cause cell death due to the expression of anti-apoptotic proteins. The dsRNA sensitized tubular epithelial cells to apoptosis induced by an agonistic antibody against the Fas receptor (CD95), an apoptotic pathway that eliminates infected cells. These findings indicate that tubular epithelial cells require at least two signals to undergo apoptosis, which can help preserve tubular integrity even under inflammatory conditions. Thus, sensors of viral dsRNA promote antiviral, pro-inflammatory, and pro-apoptotic responses in tubular epithelial cells, which may orchestrate the control of viral infection in the kidney.

Circulating lymphocyte subsets in different clinical situations after renal transplantation

Phenotypic characterization of T and B lymphocytes allows the discrimination of functionally different subsets. Here, we questioned whether changes in peripheral lymphocyte subset distribution reflect specific clinical and histopathological entities after renal transplantation. Sixty-five renal transplant recipients with either histologically proven (sub)clinical acute rejection or chronic allograft dysfunction, or without abnormalities were studied for their peripheral lymphocyte subset composition and compared with 15 healthy control individuals. Naive, memory and effector CD8(+) T-cell counts were measured by staining for CD27, CD28 and CD45RO/RA. In addition, we studied the CD25(+) CD4(+) T-cell population for its composition regarding regulatory Foxp3(+) CD45RO(+) CD127(-) cells and activated CD45RO(+) CD127(+) cells. Naive, non-switched and switched memory B cells were defined by staining for IgD and CD27. We found a severe decrease in circulating effector-type CD8(+) T cells in recipients with chronic allograft dysfunction at 5 years after transplantation. Percentages of circulating CD25(+) CD127(low) CD4(+) regulatory T cells after transplantation were reduced, but we could not detect any change in the percentage of CD127(+) CD45RO(+) CD4(+) activated T cells in patients at any time or condition after renal transplantation. Regardless of clinical events, all renal transplant recipients showed decreased total B-cell counts and a more differentiated circulating B-cell pool than healthy individuals. The changes in lymphocyte subset distribution probably reflect the chronic antigenic stimulation that occurs in these transplant recipients. To determine the usefulness of lymphocyte subset-typing in clinical practice, large cohort studies are necessary.

Characteristics of alloreactive T cells measured before renal transplantation

Several assays to measure pre-existing allospecific T cell immunity in renal transplant candidates have been developed in the past years. In 46 patients, we used flow cytometry-based mixed lymphocyte culture to measure the precursor frequency and phenotype of alloreactive T cells before renal transplantation, using donor-specific or third-party cells for allostimulation. Allostimulation induced up-regulation of co-stimulatory molecules, chemokine receptors relevant for migration of T cells into the graft and effector proteins. Recipients prone for acute rejection had a higher precursor frequency of alloreactive CD8(+) T cells and a lower percentage of interleukin (IL)-7Rα expressing alloreactive CD8(+) T cells than non-rejectors. These data point to quantitative and qualitative differences between T cells of patients who will experience acute cellular rejection episodes from those who will not.

Risk factors for delayed graft function after hand-assisted laparoscopic donor nephrectomy

BACKGROUND

Delayed graft function (DGF) has a negative effect on the results of living-donor kidney transplantation.

OBJECTIVE

To investigate potential risk factors for DGF.

METHODS

This prospective study included 200 consecutive living donors and their recipients between January 2002 and July 2007. Delayed graft function was defined as need for dialysis within the first postoperative week.

RESULTS

Delayed graft function was diagnosed in 12 patients (6%). Intraoperative complications occurred in 10 donors (5%), and postoperative complications in 24 donors (13.5%). One-year kidney graft survival with vs without DGF was 52% and 98%, respectively (P < .002). In donors, 2 univariate risk factors for DGF identified were lower counts per second at peak activity during scintigraphy, and multiple renal veins. In recipients, only 2 or more kidney transplantations and occurrence of an acute rejection episode were important factors. At multivariate analysis, increased risk of DGF was associated with the presence of multiple renal veins (odds ratio, 151.57; 95% confidence interval, 2.53-9093.86) and an acute rejection episode (odds ratio, 78.87; 95% confidence interval, 3.17-1959.62).

CONCLUSION

Hand-assisted laparoscopic donor nephrectomy is a safe procedure. The presence of multiple renal veins and occurrence of an acute rejection episode are independent risk factors for DGF.

Mumps: not an innocent bystander in solid organ transplantation

Recently two major outbreaks of mumps have occurred: in the UK more than 56,000 cases were notified between 2004 and 2005, and in the United States, 6,584 cases were reported in 2006. Most patients were young healthy adults, in whom mumps normally has a benign course. Little is known about mumps in the immunocompromised patient. Here, we report a case of a 56-year renal transplant recipient who developed acute irreversible transplant failure due to interstitial nephritis caused by mumps. RNA of the mumps virus was detected in the urine as well as in a renal biopsy. In view of the ongoing presence of the mumps virus in the population, one should be aware of the possible occurrence of this infection in immunocompromised patients.

Severe cerebral toxoplasma infection cannot be excluded by a normal CT scan

A fatal case is reported concerning a severely immunocompromised 50-year-old female renal transplant recipient who developed fever and confusion. Cerebral imaging with contrast-enhanced computed tomography (CT) scans showed no abnormalities while subsequently performed magnetic resonance imaging (MRI ) showed clear abnormalities in the basal ganglia. By that time serology and polymerase chain reaction had confirmed the diagnosis of cerebral toxoplasmosis. Because of the suboptimal sensitivity of these tests negative results should be handled with care. Once cerebral toxoplasmosis is suspected in at-risk patients, treatment should be started empirically pending the confirmation of the diagnosis. A normal cerebral CT scan does not preclude cerebral toxoplasmosis.In these situations MRI can give important additional information.

[Late complications following renal transplantation]

The number of renal transplant recipients is increasing steadily. Physicians from all specialties are ever more likely to encounter this vulnerable group of patients. They constitute a susceptible group because of increased mortality and morbidity. Half of the renal transplants are lost due to chronic transplant failure. The primary cause of chronic transplant failure is chronic allograft nephropathy. Other causes of transplant failure are calcineurin inhibitor toxicity, recurrence of the original renal disease such as glomerulonephritis and diabetes mellitus, stenosis of the renal artery in the transplant, and urological complications. The other half of the renal transplants are lost due to the death of the recipient. The primary cause of death is cardiovascular disease due to former chronic renal, hypertension and dyslipidemia following the use of immunosuppressants. In addition malignancies, infections and bone abnormalities do occur more frequently as compared to the normal populations. Alertness is warranted following kidney transplantation by both the patients themselves as well as all the treating specialists. Careful periodical monitoring for life is required because of the risk of the abovementioned complications.

The pyrimidin analogue cyclopentenyl cytosine induces alloantigen-specific non-responsiveness of human T lymphocytes

Cyclopentenyl cytosine (CPEC) has been shown to induce apoptosis in human T lymphoblastic cell lines and T cells from leukaemia patients. In this study we have addressed the question of whether CPEC is able to decrease proliferation and effector functions of human alloresponsive T lymphocytes and induce T cell anergy. The proliferative capacity of human peripheral blood mononuclear cells in response to allogeneic stimulation was measured by 5,6-carboxy-succinimidyl-diacetate-fluorescein-ester staining. Flow cytometric analysis was performed using surface CD4, CD8, CD25, CD103 and intracellular perforin, granzyme A, granzyme B, caspase-3 and forkhead box P3 (FoxP3) markers. The in vivo immunosuppressive capacity was tested in a murine skin graft model. Addition of CPEC at a concentration of 20 nM strongly decreased the expansion and cytotoxicity of alloreactive T cells. Specific restimulation in the absence of CPEC showed that the cells became anergic. The drug induced caspase-dependent apoptosis of alloreactive T lymphocytes. Finally, CPEC increased the percentage of CD25(high) FoxP3+ CD4+ and CD103+ CD8+ T cells, and potentiated the effect of rapamycin in increasing the numbers of alloreactive regulatory T cells. Treatment with CPEC of CBA/CA mice transplanted with B10/Br skin grafts significantly prolonged graft survival. We conclude that CPEC inhibits proliferation and cytotoxicity of human alloreactive T cells and induces alloantigen non-responsiveness in vitro.

The Dutch Fabry cohort: diversity of clinical manifestations and Gb3 levels

BACKGROUND

Fabry disease (OMIM 301500) is an X-linked lysosomal storage disorder with characteristic vascular, renal, cardiac and cerebral complications. Globotriaosylceramide (Gb(3)) accumulates in Fabry patients as a result of alpha-galactosidase A deficiency. The phenotypic variability is high, but the relationship between clinical symptoms in individual Fabry patients has not been uniformly documented. Also, the relation between the most prominent biochemical abnormalities, elevated Gb(3) levels in plasma and urine, and clinical symptoms is not firmly established.

METHODS

Clinical and biochemical characteristics of 96 (25 deceased) Dutch Fabry patients were collected retrospectively and before the initiation of enzyme therapy.

RESULTS

Clinical assessment revealed that median life expectancy was 57 years for male and 72 years for female patients. Cerebral complications, acroparaesthesias and gastrointestinal complications, but not cardiac and auditory complications, were all seen more frequently in male than female patients. Glomerular filtration rate (GFR) was highly variable in male patients, including 2 patients with GFR < 30 ml/min, but median GFR did not differ between males and females (103 and 101 ml/min, respectively). Hyperfiltration was more frequently observed in the female patient group. Microalbuminuria was present in 60% of males and 45% of females. No specific pattern of combined symptoms existed except for a relationship between left ventricular hypertrophy (LVH) and cerebral complications (males 36%, females 32%), or proteinuria (males 35%, females 31%). Gb(3) was found to be more elevated in plasma samples from male (n = 26; median 6.27 micromol/L (1.39-9.74)) than female Fabry patients (n = 37; median 2.16 (0.77-4.18)). This was also observed for urinary Gb(3): males (n = 22) median 1851 nmol/24 h (40-3724); females (n = 29) median 672 (86-2052). Plasma and urinary Gb(3) levels correlated with each other in both males (r = 0.4, p = 0.05) and females (r = 0.4, p = 0.03), but no correlation between elevated Gb(3) levels and clinical symptoms could be detected.

CONCLUSION

Analysis of the characteristics of the Dutch Fabry cohort has revealed that a limited relationship between various disease manifestations exists and that individual symptoms do not correlate with elevated urinary or plasma Gb(3) levels, limiting their value as surrogate disease markers.

[The first 100 hand-assisted laparoscopic donor nephrectomies at the Academic Medical Center in Amsterdam]

OBJECTIVE

To evaluate the results of the first 100 hand-assisted donor nephrectomies in our hospital.

DESIGN

Prospective, descriptive.

METHOD

In the period January 2000-July 2004, 100 consecutive donors underwent laparoscopic nephrectomy as part of a living-related kidney transplantation at the Academic Medical Center in Amsterdam, the Netherlands. The operation was performed laparoscopically using a hand port (hand-assisted nephrectomy). The incision made for the hand port was also used for the removal of the kidney.

RESULTS

Mean operating time was 168 min (range: 88-285). Median warm ischaemia time was 3 min (1.0-4.5) and median blood loss was 50 ml (20-1500). None of the operations required conversion to an open procedure and there were no deaths among donors or recipients. Postoperatively, 12 complications occurred in 10 donors. Median hospital stay for the donors was 5 days. In 3 recipients, the transplanted kidney had to be removed within 14 days. 1n 3 other recipients, surgical re-intervention was necessary due to urological complications. One-year graft survival was 94%.

CONCLUSION

Hand-assisted laparoscopic donor nephrectomy was a safe and minimally invasive procedure for renal transplantation in this patient series.

Hand-assisted laparoscopic live donor nephrectomy

Background

Hand-assisted laparoscopic donor nephrectomy (HLDN) may have advantages over laparoscopic donor nephrectomy, such as shorter learning curve, operation and warm ischaemia times. The aim of this study was to evaluate the feasibility and safety of HLDN.

Methods

Between January 2000 and October 2002, 50 consecutive HLDN procedures were performed through a low transverse abdominal incision, 23 right sided and 27 left sided.

Results

The median age of the donors was 44 years. No HLDN required conversion to an open procedure. The median operating time for HLDN was 153 min. The median warm ischaemia time was 3 (range 1·0–4·5) min and the median blood loss was 50 (range 20–500) ml in both left- and right-sided procedures. Eight patients suffered ten minor complications during their admission. The duration of hospital stay was 5 days for donors. Three recipients developed graft failure owing to acute rejection, renal vein thrombosis and ischaemic necrosis.

Conclusion

Both left- and right-sided HLDN procedures were feasible and safe through a low transverse abdominal incision.

Renal artery clip dislodgement during hand-assisted laparoscopic living donor nephrectomy

The main reason for conversion in laparoscopic donor nephrectomy (LDN) is peroperative bleeding. One of the advantages of hand-assisted laparoscopic donor nephrectomy (HDLN) is facilitated control in case of bleeding. This report describes two methods to avert conversion in HLDN in the case of abrupt major arterial bleeding. In the first case, during left HLDN the clips placed on the renal artery dislodged, and the surgeon managed to control the bleeding by compressing the focus of the bleeding with his finger. A balloon occlusion catheter was inserted through a groin incision in the aorta and advanced to the origo of the renal artery. Due to control of the hemorrhage, it was possible to close the renal artery stump by laparoscopic suturing, and a conversion was averted. The patient was discharged after 5 days, without signs of damage to the remaining kidney. In the second case, during right HLDN, the clips on the renal artery dislodged during stapling of the renal vein. The bleeding was controlled by finger compression and new clips were placed. The cuff of the artery was long enough to be clipped again. The patient was discharged after 5 days. Graft function was excellent in both cases. Major arterial bleeding can be controlled and managed in hand-assisted laparoscopic surgery. The use of a balloon occlusion catheter is an elegant way to avert conversion.

Treatment of acute kidney allograft rejection with a non-mitogenic CD3 antibody

T3/4.A is a non-mitogenic murine IgA mAb to human CD3 that was selected for clinical studies to provide an alternative for the mitogenic, T cell-activating, therapeutic mAb OKT3. Previously, we reported that T3/4.A is better tolerated in humans than the IgG2a-CD3 mAb T3/4.2a. Here we report the results of a phase II clinical trial to assess the immunosuppressive potential of T3/4.A. Eighteen first kidney transplant recipients with a first rejection episode were included. Baseline immunosuppression consisted of cyclosporin and prednisolone. Rejection treatment consisted of 5 mg mAb per day during 10 days. Fourteen patients responded, of whom four experienced a second rejection within 2 weeks, one experienced chronic rejection after 2.5 years, whereas the others remained rejection-free after treatment (median duration of follow-up 42 months). Four patients did not respond and eventually lost their graft. These results are similar to treatment results with OKT3, as reported in the literature. Following the first dose of T3/4.A, side effects were limited, and reduced compared to OKT3-treated controls. On the second day, 15 patients developed transient vomiting and/or diarrhoea, which coincided with elevated serum levels of proinflammatory cytokines. Minimal or even no side effects occurred during the remaining days, which is in sharp contrast to that seen generally during OKT3 treatment. Both T cell numbers and TCR expression were reduced during the therapy. We conclude that T3/4.A is a good alternative for OKT3 to treat rejection episodes in renal transplant recipients.

[Immunology in medical practice. XXX. Organ transplantation: indications and results]

During the past 30 years, solid organ transplantation has developed into a routine medical procedure. Currently, one-year transplant survival rates for kidney, heart, liver and pancreas are between 80 and 90%; for most organs, the long-term results are fair with 5-year survival rates of 60%. Inclusion criteria for potential recipients have become less stringent. These days, potential recipients are rarely excluded on the basis of their calendar age alone. The development of more and stronger immunosuppressive drugs has facilitated transplantation across wider immunological differences between donor and recipient with good results. While the number of patients on the waiting lists for organ transplantation increased, the number of organs offered for donation decreased. This has resulted in waiting times of several years for most organ transplantations. While the short-term outcome has improved significantly over the past decades, the long-term outcome has not. Most renal transplants, for example, are lost due to chronic rejection. The challenge for the future will be to improve the long-term outcome of organ transplantation and to decrease the morbidity associated with chronic immunosuppressive therapy.

Activation and increased expression of adhesion molecules on peripheral blood lymphocytes is a mechanism for the immediate lymphocytopenia after administration of OKT3

We investigated the mechanism by which antihuman CD3 monoclonal antibodies of the isotypes IgG2a (eg, OKT3) and IgA (eg, IXA) can induce the rapid disappearance of virtually all circulating T lymphocytes. We hypothesize that upregulation of adhesion molecules on the lymphocyte membrane contributes to this effect. However, this hypothesis is difficult to test, because of the inherent lymphocytopenia and/or shifts in lymphocyte populations between intra and extra-vascular compartments. Therefore, studies in vitro were performed, as well. Analysis of peripheral blood lymphocytes isolated at several times after addition of OKT3 or IXA to whole blood of healthy individuals showed an immediate increase in the proportion of T cells expressing NKI-L16, an activation epitope on CD11a/CD18. Likewise, an increase in CD11b/CD18 expression occurred. In parallel experiments, a transiently increased adhesion of T cells to endothelial cell monolayers was observed. This adhesion could be completely blocked by anti-CD18 or anti-CD11a monoclonal antibodies and only partly by an anti-CD11b antibody. Our data indicate that upregulation of activation epitopes of CD11a/CD18, as well as increased expression of CD11b/CD18 on T lymphocytes, may result in increased adhesion of these cells to intercellular adhesion molecule-1 (ICAM-1) and ICAM-2 on vascular endothelium. This phenomenon may, at least, partly explain the rapidly occurring peripheral lymphocytopenia observed in vivo.

Biphasic granulocytopenia after administration of the first dose of OKT3

The effects of the administration of OKT3, a second immunoglobulin G2a (IgG2a) anti-CD3 monoclonal antibody (mAb), and its isotype switch variant IgA on granulocyte kinetics were compared for 5 hours after the first administration of the mAb. In addition, in vivo and in vitro studies were performed on alterations in expression of CD11b and CD62L induced by these mAbs. Within 15 minutes after administration OKT3 and IgG2a anti-CD3 mAbs induced a significant decrease in circulating granulocytes, whereas IgA anti-CD3 mAb did not. Apparently the initial decrease in circulating granulocytes depends on the heavy chain of the administered anti-CD3 mAb, resulting in immunocytoadherence and sequestration in the lungs. Increased adherence to pulmonary endothelium by altered expression of CD11b and CD62L plays a minor role in this first granulocytopenia, because each mAb exerted the same effects on these adhesion molecules in vitro. The second decrease in granulocyte counts occurred 60 minutes after administration of each mAb and correlated with a significant increase in expression of CD11b and CD62L in vivo and with upregulation of CD11b and down-regulation of CD62L in vitro. These alterations could be related to the presence of tumor necrosis factor-alpha both in vivo and in vitro. Thus granulocyte kinetics from 30 minutes after administration of each anti-CD3 mAb resemble neutrophil kinetics induced by TNF-alpha.

[Alcoholism and dentistry]

In this article the physical and psychological consequences of alcohol abuse are considered. In addition the interaction between alcohol abuse and oral health and dentistry is discussed.

Toxicity of OKT3 increases with dosage: a controlled study in renal transplant recipients

In the present study we prospectively compared side effects occurring in 12 patients after the first administration of low-dose OKT3 (0.5 mg twice daily) induction therapy with those in 10 patients who were treated with a conventional dose of OKT3 (5 mg daily) for acute rejection. We also investigated cytokine release and activation of complement and neutrophils as all of these are held responsible for OKT3-induced side effects. Low-dose OKT3 resulted in a significantly decreased side effects score compared to that after a conventional dose of OKT3 (1.8 vs 5.1, p = 0.0006). Following the first administration of low-dose OKT3, TNF peak levels were significantly lower than after a conventional dose of OKT3. In contrast to our data on conventional dose OKT3 treatment, the first administration of low-dose OKT3 did not induce complement activation as reflected by C3a and C4b/c levels in plasma. Finally, the increase in neutrophil degranulation products lactoferrin and elastase-varies; is directly proportional to 1-antitrypsin was much less following 0.5 mg OKT3 than following 5 mg. We conclude that OKT3-induced toxicity is dose-dependent and is mediated not only by cytokine release but also by activation of complement and neutrophils.

[Corticosteroids in dental practice]

In this article some pharmacologic aspects of corticosteroids and their main medical indications are reviewed. In addition, the use of corticosteroids in dentistry and their interference with dental treatment are discussed.