Early Conversion to Prednisolone/Everolimus as an Alternative Weaning Regimen Associates With Beneficial Renal Transplant Histology and Function: The Randomized-Controlled MECANO Trial

In renal transplantation, use of calcineurin inhibitors (CNIs) is associated with nephrotoxicity and immunosuppression with malignancies and infections. This trial aimed to minimize CNI exposure and total immunosuppression while maintaining efficacy. We performed a randomized controlled, open-label multicenter trial with early cyclosporine A (CsA) elimination. Patients started with basiliximab, prednisolone (P), mycophenolate sodium (MPS), and CsA. At 6 months, immunosuppression was tapered to P/CsA, P/MPS, or P/everolimus (EVL). Primary outcomes were renal fibrosis and inflammation. Secondary outcomes were estimated glomerular filtration rate (eGFR) and incidence of rejection at 24 months. The P/MPS arm was prematurely halted. The trial continued with P/CsA (N = 89) and P/EVL (N = 96). Interstitial fibrosis and inflammation were significantly decreased and the eGFR was significantly higher in the P/EVL arm. Cumulative rejection rates were 13% (P/EVL) and 19% (P/CsA), (p = 0.08). A post hoc analysis of HLA and donor-specific antibodies at 1 year after transplantation revealed no differences. An individualized immunosuppressive strategy of early CNI elimination to dual therapy with everolimus was associated with decreased allograft fibrosis, preserved allograft function, and good efficacy, but also with more serious adverse events and discontinuation. This can be a valuable alternative regimen in patients suffering from CNI toxicity.

[Intestinal perforation caused by tuberculosis in a kidney transplant patient who was extensively evaluated for tuberculosis prior to transplant]

A 47-year-old man from Armenia presented at the emergency department with abdominal pain. He had had a kidney transplant 2 years earlier for renal failure caused by amyloidosis that was secondary to familial Mediterranean fever. He was also known to have chronic hepatitis B with persistent viraemia. He had not received any prophylactic anti-tuberculosis treatment due to impaired liver function, but an extensive work-up was performed prior to transplant, including chest radiography, a Mantoux tuberculin skin test and cultures from 3 consecutive fasting gastric lavage samples, which were all negative for active or latent tuberculosis infection. The patient had presented at the emergency department repeatedly with abdominal pain that was attributed to the familial Mediterranean fever. During his last visit his complaints were accompanied by vomiting, coughing, night sweats and weight loss. He was diagnosed with an intestinal perforation with faecal peritonitis and underwent several laparotomies to treat the faecal peritonitis. Histopathological examination of resected bowel tissue revealed granulomatous inflammation, and acid-fast bacilli were seen with appropriate staining. Later, cultures appeared to be positive for normally sensitive Mycobacterium tuberculosis. The patient died as a result of the disseminated tuberculosis. In immunocompromised patients, tuberculosis often has an atypical course and an increased chance of dissemination that may be difficult to recognize.

Initial cytomegalovirus prophylaxis with ganciclovir: no guarantee for prevention of late serious manifestations of CMV after solid organ transplantation

A 37-year-old woman presented with malaise, upper abdominal pain and fever seven months after renal transplantation. She was seronegative for cytomegalovirus (CMV) and had received a kidney from a seropositive donor. She had received CMV prophylaxis (oral ganciclovir) for three months after transplantation. During this period all tests for CMV remained negative. On admission, she presented with symptoms compatible with an acute abdomen and with deterioration of renal function. On emergency laparotomy a perforation of the ileum was found. The resected specimen showed an ulcer with vasculitis at the site of perforation, with both microscopic (owl's eye inclusion bodies), as well as immunohistochemical evidence for a CMV infection. CMV can reactivate (usually in the first three months) after transplantation, sometimes resulting in serious morbidity. The use of antiviral prophylaxis during and after transplantation has certainly decreased the number and severity of CMV infections. This case illustrates that life-threatening infections such as CMV can still emerge a long time after transplantation. Unrelenting awareness of this condition is mandatory, even after apparently adequate anti-CMV prophylaxis.

Pulmonary involvement during cytomegalovirus infection in immunosuppressed patients

Although cytomegalovirus (CMV) pulmonary involvement after solid organ transplantation is infrequently seen nowadays, CMV pneumonitis is still a potential lethal complication. Introduction of the pp65 antigenemia assay enabled early and rapid diagnosis of CMV viremia in transplant patients prior to symptoms. Also, in asymptomatic patients with CMV viremia, a decreased pulmonary diffusion capacity could be demonstrated. In this review, we discuss clinical and subclinical pulmonary involvement of CMV infection in the immunocompromised host with an emphasis on transplant recipients. The clinical course, diagnosis, therapy, prophylaxis, and pathophysiology of CMV pneumonitis are discussed.

Effects of changing immunosuppressive regimen on the incidence, duration, and viral load of cytomegalovirus infection in renal transplantation: a single center report

Background. In this retrospective single center study we have evaluated the relation between the immunosuppressive regimen and the incidence and characteristics of cytomegalovirus (CMV) infection in the setting without CMV prophylaxis from 1989 through 1998. Methods. All (470) first cadaveric renal transplantations in nonsensitized (PRA < 60%) patients were analyzed. Immunosuppression consisted of cyclosporine A (Sandimmune) and prednisolone from 1989 through 2-1993 (S; 189 patients), of cyclosporine microemulsion (Neoral) and prednisolone from 3-1993 through 5-1997 (N; 200 patients) and of mycophenolate mofetil, Neoral and prednisolone from 5-1997 until 1998 (M; 81 patients). The CMV pp65-antigenemia was measured routinely at least once weekly from day 10 till 12 weeks after transplantation or until pp65-antigenemia became negative. No CMV-prophylaxis was given. Results. By changing from Sandimmune to Neoral and by adding mycophenolate mofetil, respectively, we observed a higher frequency of especially secondary CMV infections (S vs. N vs. M, respectively, 28 vs. 50 vs. 63%, P = 0.026; S vs. N, P = 0.027; S vs. M, P = 0.015; and N vs. M, n.s). The CMV infections lasted longer (median duration antigenemia S vs. N vs. M, respectively, 3 vs. 5 vs. 7 weeks, P = 0.0003; S vs. N, P < 0.002; S vs. M, P < 0.001; and N vs. M, P < 0.05). Viral load was higher in M (median maximal pp65-antigenemia S vs. N vs. M, respectively, 19 vs. 14.5 vs. 73, P < 0.01; S vs. N, n.s.; S vs. M, P < 0.001 and N vs. M, P < 0.01). Conclusions. The use of Neoral and the addition of mycophenolate mofetil caused significant changes in the incidence, duration and viral load of CMV infections.

Pulmonary diffusion abnormalities in relation to cytomegalovirus antigenemia and cytomegalic endothelial cells in blood

The pathophysiology of HCMV infection may involve many different organs including the lungs. In this study we investigated HCMV antigenemia levels and cytomegalic endothelial cells (CEC) in blood in relation to the pulmonary diffusion capacity. Patients with high HCMV antigenemia (> or = 100 pp65+ PMNs/50.000) (n = 8) showed a more extensive decrease in the membrane factor (Dm) than patients with lower levels of HCMV antigenemia (n = 7). The decline of the diffusion capacity of the alveolar capillary membrane (KCOc) and of the pulmonary capillary volume (Vcap) was the same in both groups. Four out of nine patients had CEC in the range of 0.22 CEC/ml to 30.26 CEC/ml. All the HCMV patients showed a decreased KCOc together with a decrease of Dm and Vcap but no difference was observed between patients with and without CEC. We conclude that a higher viral load is associated with a more extensive decrease in the membrane factor and therefore with more subclinical pneumonitis. No relation was observed between CEC and pulmonary dysfunction. Therefore, we postulate that CEC levels are related indirectly to subclinical pneumonitis mediated via the viral load.

Cytomegalovirus infection increases the expression and activity of ecto-ATPase (CD39) and ecto-5'nucleotidase (CD73) on endothelial cells

We describe enhanced expression and enzymatic activity of ecto-ATPase and ecto-5'nucleotidase on CMV infected endothelial cells as compared to uninfected cells. These ectoenzymes play a major role in modulation of platelet activation and aggregation. Furthermore, adenosine has a modulatory effect upon inflammation. Addition of ATP, ADP or AMP to cultures of CMV infected or uninfected endothelial cells revealed increased turnover of AMP in CMV infected endothelial cells. In addition, the superoxide production by stimulated polymorphonuclear cells was inhibited in the presence of CMV infected endothelial cells as compared to uninfected cells, probably due to the enhanced activity of ecto-5'nucleotidase and associated to production of adenosine.

Overcoming the problem of cytomegalovirus infection after organ transplantation: calling for Heracles?

Although diagnosis of CMV infections and treatment of CMV disease with effetive antiviral drugs have become much easier, the persistent problem of CMV infection after solid-organ transplantation still requires solid knowledge of the pathophysiology of its clinical manifestations in order to minimize the impact of CMV infections in the future. The complex symptomatology of CMV infection after solid-organ transplantation is reviewed as well as some of the new theories attempting to explain the myriad of symptoms seen after transplantation.

Uninfected and cytomegalic endothelial cells in blood during cytomegalovirus infection: effect of acute rejection

After transplantation, human cytomegalovirus (HCMV) infections can cause vascular damage to both the graft and the host. To study a possible relationship between the degree of vascular injury, clinical symptoms of HCMV infection, and transplant rejection, the appearance and numbers of endothelial cells (ECs) in blood of 54 kidney transplant recipients were investigated in a prospective clinical study. Two types of endothelial cells were identified: cytomegalic ECs (CECs) were detected in patients with moderate or high HCMV antigenemia, and uninfected ECs were observed in patients with and without HCMV infection. The incidence of either CECs, ECs, or the combination of both was associated with HCMV-related clinical symptoms (P<.01). Remarkably, the occurrence of rejection episodes before HCMV infection was an important risk factor for the occurrence of ECs in blood (ECs, CECs, or both) during HCMV infection (P<.001).

Cytomegalovirus pneumonitis after kidney transplantation is not caused by plugging of cytomegalic endothelial cells only

In addition to life-threatening pneumonia, cytomegalovirus (CMV) may also cause subclinical pulmonary dysfunction after kidney transplantation. To investigate the role of plugging of cytomegalic endothelial cells in the pulmonary capillary bed, we prospectively determined specific carbon monoxide diffusion capacity (KCOc) and its components: the pulmonary diffusing membrane factor (Dm) and pulmonary capillary blood volume (Vcap) before and during CMV infection in 13 kidney transplant recipients and 13 controls. During CMV infection, mean KCOc decreased significantly by 28 % of the initial value (mean KCOc 79 vs 109; P < 0.005 ) due to a decrease in both Vcap and Dm. The KCOc in controls showed a significantly smaller decrease due to a slightly lower Vcap. We conclude that kidney transplant recipients with CMV infection have significant pulmonary diffusion disturbances due to a combination of lower Vcap and lower Dm. The most likely explanation for this phenomenon is a local inflammatory process due to CMV and not plugging of cytomegalic endothelial cells only.

A sensitive method for quantifying cytomegalic endothelial cells in peripheral blood from cytomegalovirus-infected patients

A sensitive method has been developed for the quantification of cytomegalic endothelial cells (CEC) in peripheral blood (PB) of patients with active cytomegalovirus (CMV) infections. The three subsequent key steps of this method are density centrifugation to enrich endothelial cells (EC) in the mononuclear cell (MNC) fraction, EC-specific staining, and fluorescence-activated cell sorting (FACS) of EC onto adhesion slides. The FACS method was compared with the conventional method of cytocentrifugation of the MNC fraction onto slides, followed by EC-specific staining. The main advantage of the additional steps for the isolation and quantification of CEC in PB by FACS is a 10-times-greater sensitivity than by cytocentrifugation of the MNC fraction alone. The recovery percentages of EC from whole blood were comparable for both methods. Recoveries of EC obtained after FACS were 53% +/- 16.5%, (mean +/- standard deviation), and recoveries of EC obtained after cytocentrifugation of the MNC fraction were 43% +/- 4.3%. In patients with active CMV infection, 5 to 72 CEC were detected by FACS, equivalent to 0.8 to 9.0 CEC/ml of blood. With this method for isolation and quantification, the characterization of CEC in PB of patients with CMV-associated clinical symptoms, as well as the quantification of EC in PB of patients with pathophysiological manifestations involving endothelial damage that are different from those caused by CMV infections, can be performed.

Increased intestinal permeability during cytomegalovirus infection in renal transplant recipients

Cytomegalovirus (CMV) infections in renal transplant recipients can affect the gastrointestinal tract, but significant clinical manifestations are seldom seen. We hypothesize that subclinical involvement of the gastrointestinal tract may be quite frequent during CMV infection. In order to study this, we measured intestinal permeability by calculating the urinary lactulose mannitol (LM) excretion ratio after oral administration of lactulose and mannitol (normal < 0.030) in patients with symptomatic and asymptomatic CMV infection. A total of 111 patients were enrolled in the study, 104 of whom were tested on postoperative day (POD) 10. Twenty-nine patients developed CMV infection, 12 of whom could be studied with the permeability test (median POD 40). Another nine patients without CMV infection were also studied at day 40 and served as controls. The LM ratio increased significantly during CMV infection compared to measurements before active infection (median 0.060 vs. 0.030, P < 0.01) and was significantly higher during the infection than in the control group (median 0.007, P < 0.01). No correlation could be found between the LM ratio and viral load, humoral response to the virus, or symptomatology of infection. We conclude that an increased intestinal permeability is found in a substantial number of patients with an active, albeit asymptomatic, CMV infection after renal transplantation. Pathophysiological mechanisms and clinical implications remain speculative but will be subject to further study.

Increased intestinal permeability during cytomegalovirus infection in renal transplant recipients

Cytomegalovirus (CMV) infections in renal transplant recipients can affect the gastrointestinal tract, but significant clinical manifestations are seldom seen. We hypothesize that subclinical involvement of the gastrointestinal tract may be quite frequent during CMV infection. In order to study this, we measured intestinal permeability by calculating the urinary lactulose mannitol (LM) excretion ratio after oral administration of lactulose and mannitol (normal < 0.030) in patients with symptomatic and asymptomatic CMV infection. A total of 111 patients were enrolled in the study, 104 of whom were tested on postoperative day (POD) 10. Twenty-nine patients developed CMV infection, 12 of whom could be studied with the permeability test (median POD 40). Another nine patients without CMV infection were also studied at day 40 and served as controls. The LM ratio increased significantly during CMV infection compared to measurements before active infection (median 0.060 vs. 0.030, P < 0.01) and was significantly higher during the infection than in the control group (median 0.007, P < 0.01). No correlation could be found between the LM ratio and viral load, humoral response to the virus, or symptomatology of infection. We conclude that an increased intestinal permeability is found in a substantial number of patients with an active, albeit asymptomatic, CMV infection after renal transplantation. Pathophysiological mechanisms and clinical implications remain speculative but will be subject to further study.