Area under the viraemia curve versus absolute viral load: utility for predicting symptomatic cytomegalovirus infections in kidney transplant patients.

A novel approach to predicting symptomatic cytomegalovirus (CMV) infections combines the level and the duration of viraemia in a single parameter. Sixty-four kidney transplant recipients were monitored by quantitative shell vial culture, pp65 antigenaemia, and polymerase chain reaction (PCR) of leucocytes. The area under the curve (AUC) of each parameter was determined from the onset of viraemia to the beginning of antiviral treatment. The AUC values were significantly higher in symptomatic than in asymptomatic patients. For antigenaemia and PCR, optimal AUC thresholds for predicting symptomatic CMV infections were determined. They were superior to standard cutoff levels of absolute viral load in sensitivity, specificity, and positive and negative predictive value. In 8 of the 23 patients who became symptomatic, impending clinical features were indicated earlier by the AUC thresholds than by standard viral load. In conclusion, the concept of the AUC should facilitate identification of patients at risk of symptomatic CMV infection.

Do serum C-reactive protein measurements help to discriminate episodes of renal dysfunction in patients after renal transplantation?

INTRODUCTION: This study investigated whether serial daily measurements of serum C-reactive protein (sCRP) could help differentiate episodes of transplant dysfunction due to rejection, infection, cyclosporine A (CsA) nephrotoxicity, or acute tubular necrosis (ATN) in renal-allograft recipients. MATERIALS AND METHODS: Morning serum was obtained daily from 134 patients during the first 30 days after renal transplantation. All episodes of graft dysfunction were recorded and differentiated with transplant biopsies. CRP concentrations were correlated with post-operative graft function and the various causes of graft dysfunction. RESULTS: All patients showed an increase in sCRP in response to surgery, with a maximum on day 2 after transplantation. The sCRP concentration was significantly higher in patients with delayed graft function (mean 61.50 microg/ml) than in patients with primary graft function (mean 38.01 microg/ml) (p=0.001). Bacterial infections other than asymptomatic bacteriuria (mean sCRP 33.98 microg/ml), interstitial graft rejection (mean sCRP 16.43 microg/ml), and ATN (mean sCRP 30.50 microg/ml) were accompanied by significant increases in sCRP compared with uneventful courses. sCRP was unchanged in the presence of viral infections or CsA toxicity. CONCLUSION: Serial sCRP measurements help to identify renal-transplant dysfunction of different origins. However, rejection, infection and ATN show similar patterns of sCRP increase. Thus, sCRP is unable to discriminate the causes of renal-graft dysfunction. Biopsy remains the gold standard for the differential diagnosis of renal-allograft dysfunction.

False-positive results of plasma PCR for cytomegalovirus DNA due to delayed sample preparation.

Positive results by cytomegalovirus (CMV) PCR of plasma are considered predictive of active CMV infection in kidney allograft recipients. To assess whether contamination with leukocyte-derived CMV DNA can distort the results, aliquots of whole-blood samples from 60 CMV immunoglobulin G-positive patients with leukocyte CMV DNAemia were stored for up to 24 h at room temperature (RT) and at 4 degrees C before plasma preparation. Native and ultrafiltered plasma samples were tested by CMV and beta-globin PCRs. Among 30 latently infected patients (negative for CMV pp65 antigens), low baseline rates (10%) and levels (median number of copies, 10 [per 10 microl]) of CMV plasma DNAemia in native plasma samples increased significantly over time (after 4 h at RT, 37% [P < 0.001]; median number of copies, 45 [P < 0.001]). Similar effects were found during storage at 4 degrees C. Ultrafiltration reduced the levels of CMV plasma DNAemia, but by 6 h of storage the levels were significantly elevated as well. CMV and beta-globin DNA kinetics in plasma were parallel. In contrast, 30 actively infected patients (pp65 positive) had high baseline rates (87% in native samples) and levels (median number of copies, 75) of CMV plasma DNAemia. No significant effects of storage or ultrafiltration and no concordance with beta-globin DNA kinetics were seen. In conclusion, delayed preparation of plasma samples bears a significant risk of false-positive CMV PCR results, probably due to leukocyte lysis. This has important implications in the clinical setting and for PCR standardization.

Cytomegalovirus cultured from different major leukocyte subpopulations: association with clinical features in CMV immunoglobulin G-positive renal allograft recipients.

Cytomegalovirus (CMV) cultured from peripheral blood mononuclear cells (PBMCs) was shown to be associated more closely with clinical manifestations than infectious CMV in polymorphonuclear leukocytes (PMNLs) of renal allograft recipients with secondary CMV infection. Shell vial culture was carried out with ficoll-purified PBMCs and PMNLs of 71 CMV IgG-positive patients after kidney transplantation. Thirty-six patients experienced active CMV infections. Of these, 17 developed clinical symptoms. The diagnostic value of PMNLs and PBMCs viremia was determined in comparison to pp65 antigenemia, leukoDNAemia, plasma DNAemia, and detection of cytomegalic endothelial cells. In both PMNLs and PBMCs (with or without detectable endothelial cells), frequencies and levels of viremia were significantly higher among symptomatic patients. Regarding the occurrence of clinical CMV manifestations, the sensitivity of culture from PMNLs and from PBMCs fractions was 100%. Viremia in PBMCs, however, was far more specific (94%) than in PMNLs (74%). Cutoff values established previously for pp65 antigenemia and leukoDNAemia, standard markers in the laboratory, had similar specificity (96% each) to PBMCs viremia, but were less sensitive (88% each). Plasma DNA-emia was both less sensitive (82%) and less specific (69%) than PBMCs viremia. Detection of endothelemia showed maximal specificity (100%), but inferior sensitivity (47%). All patients had PBMCs viremia before the onset of symptoms. In conclusion, infectious CMV present in PBMCs may prove to be a determinant of clinical CMV manifestations in seropositive immunocompromised individuals. Factors involved in PBMCs tropism may help to understand the pathogenetic mechanisms of CMV dissemination in this group of patients.

Pulsed-field gel electrophoresis for the analysis of Listeria monocytogenes infection clusters after kidney transplantation.

Listeria monocytogenes causes a rare, life-threatening infection in recipients of transplanted organs. We used cultures of blood and cerebrospinal fluid to characterize isolates and to distinguish cases in clusters from what might have been sporadic cases. From December 1994 to November 1995, six systemic L. monocytogenes infections occurred at our renal-transplantation unit. We confirmed the clinical diagnosis with blood and cerebrospinal fluid cultures and characterized the isolates retrospectively with pulsed-field gel electrophoresis (PFGE), phage-typing, and serotyping. We also performed an environmental investigation (food, drug, and stool). We took samples after the first two L. monocytogenes infections and then after cases three and four occurred. All patients recovered completely, and no graft was lost. Four patients had identical or genetically related L. monocytogenes isolates in PFGE (type A) and serotyping (type 1/2b). The other two had PFGE type B and G. L. monocytogenes was not detected in food or drug samples from patients on the renal-transplantation ward or in stool samples from the ward staff. It was concluded that PFGE allows sporadic cases and cluster cases of L. monocytogenes infection to be distinguished.

[Perioperative incidence of transfusions after allogenic kidney transplantation]. / Perioperative Transfusionshäufigkeit nach allogener Nierentransplantation.

The requirement of blood transfusions was evaluated in a two compartment (retrospective/prospective) study in our renal transplantation program. Between July 1st, 1993 and December 31st, 1994 (observation period 1) we retrospectively investigated 110 patients with end stage renal disease and anemia undergoing kidney transplantation. Between January 1st, 1995 and December 31st, 1996 (observation period II) the requirement of blood transfusions was followed prospectively in 134 patients after allogenic renal transplantation. The amount of blood drawn for preoperative diagnostic investigations was in observation period 1 significantly higher (280 ml) than in observation period II (150 ml) (p = 0.02). For postoperative diagnostic tests in observation period II significantly less blood (240 ml) was needed than in observation period 1 (510 ml) (p = 0.01). The intraoperative blood loss was similar in both periods (170 ml vs. 190 ml; p = 0.6). The need for closer graft observation was the reason for significantly increased amount of blood transfusions in patients with delayed graft function. The number of blood transfusions was significant lower in patients with primary graft function (p = 0.0001). There was no correlation between blood transfusions and the use of ATG/OKT3, surgical complications and reoperations. With an improved management of blood drawing for diagnostic tests after allogenic kidney transplantation the number of perioperative blood transfusions can be reduced significantly.

Utility of major leukocyte subpopulations for monitoring secondary cytomegalovirus infections in renal-allograft recipients by PCR.

The feasibility of the major peripheral blood leukocyte (PBL) subsets for use in qualitative and quantitative PCR to monitor secondary cytomegalovirus (CMV) infection and ganciclovir therapy was assessed with 188 blood samples derived from 40 CMV immunoglobulin G-positive renal-allograft recipients. In pp65 antigen-positive patients all leukocyte fractions, but only 79.5% of plasma preparations, were PCR positive. In pp65 antigen-negative samples from patients after antiviral treatment only 7.3% of polymorphonuclear cell (PMNL) samples, but 81.8% of peripheral blood mononuclear cells (PBMC), and 10.9% of plasma samples remained PCR positive. Similarly, in patients with latent infections only 5.0% of PMNL, but 51.7% of PBMC preparations, and 8.0% of plasma samples were PCR positive. Regarding patients with active CMV infection, CMV DNA copy numbers in PMNL correlated significantly with pp65 antigen-positive cell counts before and after onset of ganciclovir therapy. Significant differences in CMV DNA copy numbers in PMNL and plasma were observed (i) between patients with symptomatic infection and those with asymptomatic infection and (ii) between patients with active infection and those with latent infection. In contrast, PBMC harbored equally low CMV DNA levels both in patients with active infection and those with latent infections, and no decline of CMV DNA load in PBMC was observed during antiviral treatment. We conclude that detection of CMV DNA in PMNL, not in PBMC, is associated with active infections and is more sensitive than detection of CMV DNA in plasma. Negative PCR results for PMNL after antiviral therapy indicate recovery, and fewer unwanted positive results occur compared to PBMC and plasma. Therefore, purified PMNL should be preferred for analysis by qualitative CMV PCR to avoid unwanted positive results. The CMV DNA load in PBMC compared with that in PMNL is negligible during active infection, so mixed PBL are sufficient for use in quantitative PCR.

[Occurrence of lymphoceles after allogeneic kidney transplantation and their therapy]. / Untersuchung zum Auftreten von Lymphozelen nach allogener Nierentransplantation und deren Therapie.

We conducted a prospective evaluation of 301 consecutive renal transplants to define the prevalence and therapy of lymphoceles following renal transplantation. Using a management scheme, we identified in 52 patients (17.3%) perirenal fluid collections. Using this management scheme, we treated 47/52 patients conservatively. Only 5 (1.7%) patients required internal marsupialization. We conclude that groin lympho cysts after renal transplantation can be successfully treated with conservative methods.

Nosocomial infections by Listeria monocytogenes: analysis of a cluster of septicemias in immunocompromised patients.

From December 1994 to November 1995 an unusual accumulation of Listeria infections occurred at the University Hospital Hamburg-Eppendorf, Germany. Eleven immunosuppressed patients from different departments developed septicemia due to Listeria monocytogenes during hospitalization. In a retrospective study, serotyping and pulsed-field gel electrophoresis revealed that six isolates were identical or genetically related. Four of them had been isolated from renal transplant recipients. Listeria monocytogenes was neither detected in food samples of the renal transplantation ward, nor in stool specimens obtained from the ward staff. There had been no close contacts among the infected patients. Before transplantation, the renal transplant recipients had been dialysed in different dialysis centers. Nosocomial foodborne transmission could not be proven but seems likely.

Minimal effect of delayed sample processing on results of quantitative PCR for cytomegalovirus DNA in leukocytes compared to results of an antigenemia assay.

Quantitative cytomegalovirus antigenemia and DNAemia were determined in peripheral leukocytes of 25 patients stored for up to 72 h at room temperature (RT) and 4 degrees C before processing. Numbers of antigen-positive cells significantly decreased with time. The decline was greater at RT than at 4 degrees C. In contrast, no significant alterations in DNAemia occurred.

[Femoral arteriovenous fistula and transplant malfunction after allogeneic kidney transplantation. A case report]. / Femorale arteriovenöse Fistel und Transplantatfunktionsstörung nach allogener Nierentransplantation. Ein Fallbericht.

This case report deals with the clinical history of a 52-year-old woman who suffered from delayed graft function and ischaemic pain after a technically successful renal transplantation. The past history of the patient revealed that coronary catheters had repeatedly been used for investigation and treatment of myocardial infarctions. The clinical investigation reported here revealed a typical auscultatory result with an arteriovenous (AV) fistula in the right upper limb. After performing a digital arterial angiography, an AV fistula between the femoral artery and vein was demonstrated. Operative occlusion of the fistula increased the perfusion of the kidney graft and the right limb. The patient recovered without wound infection and could leave the hospital with the transplanted kidney functioning well. This case report demonstrates that persistence of AV fistulas after angiographic investigations is rare. Operative occlusion of these lesions should be performed before kidney transplantation to avoid steal phenomena and disturbed would healing.

[Diagnosis of graft rejection]. / Diagnostik der Transplantatabstossung.

The topic of renal transplant rejection diagnosis is reviewed. The immunological and morphological findings and the clinical presentation of hyperacute, acute and chronic rejection are described. The indications for, and the value and limitations of diagnostic techniques such as core biopsy, fine-needle aspiration cytology, duplex Doppler sonography and immunological findings are analyzed. Early diagnosis and treatment are regarded as the central aim to prevent graft loss through rejection.

[Urologic complications after kidney transplantation. Experiences in a center with 539 recipients]. / Urologische Komplikationen nach Nierentransplantation. Erfahrungen eines Zentrums bei 539 konsekutiven Rezipienten.

A total of 539 renal transplantations were performed at the Department of Urology of the University Hospital of Hamburg between 1984 and 1991. 132 (24.5%) patients developed urological complications (by definition, complications occurring as a result of the operative procedure). In 31 cases the transplants had to be removed secondary to urological complications, and 4 patients died of such complications (mortality 0.7%, lethality 3.0%). Urinary tract infections occurred in 13.2% of all patients during the first postoperative year and were by far the most frequent complication, followed by haematomas, which occurred in 9.6%. The incidence of urinary tract and wound infections was significantly reduced during the 8-year period studied by improving antibiotic prophylaxis and adopting a strategy of early removal of indwelling catheters (P < 0.05). Stenting the ureteroneocystostomy with a double-J stent instead of an external ureteral catheter resulted in a definite decrease in the incidence of ureteral leaks (P < 0.05). Continuous control of operative results and efforts to improve operative and perioperative strategies make it possible to reduce the incidence of urological complications in renal transplantation and thus result in an improved graft function and patient survival.

Endo-urological cold-knife incision for ureteral stenosis after renal transplantation.

Cold-knife incision of stenoses in the transplant ureter was performed in 11 patients with upper urinary tract obstruction in renal transplants. The operations were complicated by bleeding in 2 patients and the graft had to be removed in 1 of them. The stenoses could be treated successfully in 10 of the 11 patients (91%) and the mean serum creatinine concentration decreased significantly from 3.4 to 1.8 mg./dl. After a mean of 26 months only 1 obstruction recurred, so the long-term success rate was 82%. Because of the favorable long-term results and the low incidence of complications, we recommend endo-urological cold-knife incision of ureteral stenosis as the first-line treatment for upper urinary tract obstruction in renal transplants.

[Cytomegalovirus diseases following allogenic kidney transplantation]. / Zytomegalievirus-(CMV-)Erkrankungen nach allogener Nierentransplantation.

Lymphotrophic virus infections, especially when they are caused by the cytomegalovirus, are severe complications after allogenic organ transplantation. First infections are mainly caused by donation of CMV-positive organs to CMV negative recipients. The regular incubation time of 30 to 40 days can be significantly shorter after therapeutic application with high dose prednisone or mono/polyclonal antibodies for treatment of rejection. The spectrum of clinical signs of the CMV-disease after organ transplantation can range between serological alterations and the lethal CMV-syndrome. The early recognition of virus-dependent clinical symptoms and the establishment of the diagnosis are the first conditions for the treatment, consisting in reduction of the immunosuppressive medication and application of ganciclovir, a CMV-specific virusstatic agent. The prophylactic application of CMV-hyperimmunoglobulin is discussed controversially. A very important aspect of CMV-disease in the long-term follow-up is the influence of this virus infection on the development of chronic organ rejection, which could be demonstrated in animal studies by application of the Marek virus and which was seen in pathomorphological samples of transplant biopsies. Future diagnostic and therapeutic strategies, which aim at the prolongation of the patient's survival and the transplant function have to consider the influence of virus infections as a severe risk-factor, as the transplantation of CMV-negative organs to CMV-negative recipients is more the exception than the rule.