Novel approach for improved assessment of phenotypic and functional characteristics of BKV-specific T-cell immunity.

BACKGROUND: BKV-associated nephropathy represents a serious complication of the posttransplant period in kidney transplant recipients. Monitoring BKV-specific immunity is of a special importance for estimation of clinical course in patients with BKV reactivation. Our recent data demonstrated that all five BKV antigens are immunogenic and elicit T-cell responses varying within patients. Therefore, all five BKV proteins should be evaluated for the assessment of BKV-specific immunity. However, analysis of five proteins performed separately is time- and cost-intensive and requires large amount of blood. METHODS: Using novel approach of a mixture of overlapping peptide pools encompassing all five BKV antigens (viral protein [VP] 1, VP2, VP3, large tumor antigen, and small tumor antigen) and multiparameter flow cytometry, we evaluate BKV-specific T cells in patients with a previous/present severe long-lasting or transient BKV reactivation. Patients without BKV reactivation were used as control. RESULTS: In this study, we show that using mixture of overlapping peptide pool results in the magnitude of CD4- and CD8-positive BKV-specific T-cell response, which is significantly higher compared with any frequencies detected by previously used single BKV antigen stimulation. Of interest, patients with a history of rapid BKV clearance had significantly higher frequency of multifunctional interferon gamma-γ/interleukin (IL)-2/tumor necrosis factor-α and IL-2/tumor necrosis factor-α CD4-positive T cells, suggesting protective potential of polyfunctional T cells. Furthermore, we did not find IL-17-producing BKV-specific memory T cells in patients recovered from BKV reactivation. CONCLUSIONS: Here, we established a fast and sensitive approach allowing the most comprehensive assessment of the total BKV immunity performed to date and offer a new platform for further prospective studies.

Treatment of cytomegalovirus disease with valganciclovir in renal transplant recipients: a single center experience.

Recent data suggest valganciclovir (VGC) to be as effective as ganciclovir for cytomegalovirus (CMV) prophylaxis. The objective of this study was to analyze the effect of oral valganciclovir in renal transplant patients with symptomatic CMV infection. Twenty-one patients with symptomatic CMV infection received VGC in doses adjusted to renal function until resolution of CMV antigenemia. The patients were followed for a mean of 5.5 months. During therapy, CMV antigenemia dropped in all patients from pretreatment positive levels of 5.2 +/- 3.7 to negative values of 0.25 +/- 0.2 positive cells/10,000 PBMC (P<0.001). After cessation of therapy, none of patients developed relapse of CMV antigenemia/symptoms within the follow-up. VGC therapy was well tolerated in all patients and no major adverse effects occurred. This pilot trial showed VGC to be safe and highly effective in antiviral therapy after renal transplantation. However, subsequent multicenter clinical trials for treatment of CMV disease are necessary.

Enhanced granulysin mRNA expression in urinary sediment in early and delayed acute renal allograft rejection.

BACKGROUND: Acute rejection (aRx) has a major impact on the long-term outcome of renal allografts, and its diagnosis is contingent on the invasive procedure of allograft biopsy. New immunosuppressive protocols have reduced the incidence but have not abolished this problem. Moreover, aRx is now more frequently seen several weeks after transplantation in outpatients. A noninvasive diagnostic test for predicting aRx could improve the management and outcome. The recently described measurement of urinary mRNA expression offers a new noninvasive approach. METHODS: In this study, the authors monitored the urinary mRNA expression (221 specimens from 26 patients) of various immune molecules by real-time reverse-transcriptase polymerase chain reaction for up to 3 months after kidney transplantation. Most of the patients received anti-interleukin (IL)-2 receptor monoclonal antibody induction and tacrolimus-based maintenance immunosuppression, which resulted in a low incidence of aRx. To verify the "rejection" markers, an additional nine samples of patients with aRx were analyzed. RESULTS: Granulysin mRNA increase (vs. 95% confidence interval of 159 urine samples from nonrejecting patients) was detected during 11 of 14 aRx episodes, and follow-up studies showed its predictive value for delayed aRx episodes, even weeks before enhanced serum creatinine was observed. Granulysin induction was associated with enhanced regulated on activation normal T-cell expressed and secreted (RANTES) mRNA expression in 8 of 11 samples. Other cytotoxic effector molecules (granzyme B, perforin, FasL), cytokines (tumor necrosis factor-alpha, RANTES, IL-2, IL-10, interferon-gamma, transforming growth factor-beta), CD3, and CCR1 showed less specificity and sensitivity. CONCLUSIONS: The authors' data illustrate that the noninvasive kinetic mRNA expression measurement of defined markers in urinary cells of renal allograft recipients allows the early noninvasive detection of ongoing aRx.

Kidney transplantation at the Charité: long tradition, elderly patients and the duration of hospitalization.

Since the sixties kidneys have been transplanted successfully at the 2 predecessors of today's transplant center at the Charité. So far, 1,290 kidneys were transplanted resulting in 89.8% overall graft survival at one year and 78.6% at 5 years. Several factors were associated with these results. Ischemia times were very short (11.9 +/- 7.3 hours). Patients with diabetic nephropathy were rarely transplanted without combined pancreas transplantation. Combined with a pancreas transplantation, kidney grafts fared even better than those of non-diabetic patients. The share of living donation is still rising and is associated with a better outcome than cadaveric grafts. In contrast, the effect of HLA mismatches was not very pronounced. Zero- and one-mismatch transplantations had a clear benefit over those with 2-3 mismatches, but higher numbers of mismatches did not lead to worse results. To expand the donor pool with kidneys from old donors (> 64 years) we participate in the Eurotransplant Senior Program (ESP) where these kidneys are allocated locally to recipients aged 65 years and older without HLA matching. The ischemia times for ESP kidneys were shorter (7.3 +/- 3.0 hours) but transplants were less well matched (4.2 +/- 2.1 mismatches). Graft survival was not different from controls aged 60 years and older who received a kidney from a donor under age 65. The ESP patients do not require prolonged hospitalization for transplantation (30.6 +/- 14.6 days versus 35.3 +/- 26.0 days in patients below 60 years). With the introduction of the ESP the number of transplantations in recipients aged 60 years and above have risen considerably.