Comparison of tomographic kidney volumes measured by semiautomatic segmentation method with scintigraphic split renal function in predicting posttransplant kidney functions.

INTRODUCTION: In this study, it was aimed to compare scintigraphic split renal function (SRF) and computed tomographic (CT) kidney volumes by semiautomatic segmentation method in predicting graft functions after kidney transplantation. METHODS: One hundred and twelve patients (77 males, 35 females) who had a living-donor kidney transplant between 2015 and 2017 in our centre were included in the study. While SRF was calculated with technetium-99m-diethylenetriaminepentaacetic acid (99m Tc-DTPA) scintigraphy, CT angiography was used for volumetric calculations. RESULTS: CT-volumetric measurements, especially renal cortical volume (RCV: 103.8 ± 20 ml) and ratio to body mass index (RCV/BMI: 4.45 ± 1.3) were found to be more significant than 99m Tc-DTPA-SRF in predicting graft functions. The correlations between SRF and RCV with 6th-month estimated glomerular filtration rate (eGFR) (rSRF: 0.052, rRCV: 0.317, p = 0.041) and 1st-year eGFR (rSRF: 0.104, rRCV: 0.374, p = 0.033) were found to be more significant in favour of RCV. The correlation between SRF/BMI and RCV/BMI with 1st-, 6th- and 12th-month eGFR (respectively, p = 0.02/0.048/0.024) were found to be more significant in favour of RCV/BMI. Although univariate analysis showed a significant relationship between most volumetric measurements and 1st-year graft functions, in multivariate analysis only RCV [odds ratio (OR): 1.04 (1.01-1.07), p = 0.023] and RCV/BMI [OR: 2.5 (1.27-5.39), p = 0.013] showed a significant relationship between graft functions. CONCLUSION: In our study, it was shown that CT-based renal volumetric measurements, especially RCV and RCV/BMI, predicted graft functions more strongly than scintigraphic 99m Tc-DTPA-SRF.

Effect of post-perfusion hyperoxemia on early graft function in renal transplant recipients: a retrospective observational cohort study.

BACKGROUND: The effects of hyperoxemia on the transplanted grafts arouse interest nowadays, particularly intraoperative hyperoxemia, on transplant kidney function and survival in the 1-year post-operative period. AIMS: We aimed to investigate the effect of post-perfusion (5 min after perfusion) hyperoxemia on early graft function and survival in renal transplant recipients. METHODS: Two hundred forty-seven living donor kidney transplant recipients were included in the study. Patients were divided into the three groups according to their partial arterial oxygen pressure in post-perfusion blood gas samples: group 1: normoxia (n = 52, PaO2 pressure: < 120 mmHg, 103 ± 13); group 2: moderate hyperoxemia (n = 121, PaO2: 120-200 mmHg, 169 ± 21); group 3: severe hyperoxemia (n = 74, PaO2: > 200 mmHg, 233 ± 25). Graft functions (serum creatinine levels, estimated-glomerular filtration rate values, spot urine protein/creatinine ratio), survival rates, and groups' clinical outcomes were compared in the first year after transplantation. RESULTS: Graft survival rates were similar in the groups and the rate of BK virus viremia was the lowest in the group 3 (groups 1, 2, and 3: 15.4% (n = 8), 6.6% (n = 8), 1.4% (n = 1), respectively, P: 0.009). Serum creatinine and proteinuria levels were lower, and estimated-glomerular filtration rate values were higher in group 3. A negative correlation between partial arterial oxygen pressure and serum creatinine levels and a positive correlation with estimated-glomerular filtration rate value were noted. These results were confirmed by univariate and multivariate analyses. CONCLUSIONS: We demonstrated that the kidney transplant recipients with post-perfusion hyperoxemia have better early graft functions and lower BK virus viremia rates. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04420897.

[Monitoring of cytomegalovirus-specific CD4+ and CD8+ T cell responses by cytokine flow cytometry in renal transplant recipients]. / Böbrek nakil hastalarinda sitomegalovirusa özgül CD4+ ve CD8+ T hücre yanitinin sitokin akim sitometri yöntemiyle izlemi.

In spite of the improvements in the clinical management of solid organ transplant (SOT) recipients provided by immunosuppresion and universal prophylaxis, human cytomegalovirus (CMV) infections continue to be one of the most leading causes of morbidity and mortality. Cell-mediated immunity specific to CMV (CMV-CMI) plays an important role in the control of CMV replication. Therefore, monitoring of CMV-specific T-cell response can be used to predict individuals at increased risk of CMV disease. The aim of this study was to investigate the levels of CMV-specific interferon (IFN)-γ producing CD4(+) and CD8(+) T cells in kidney transplant recipients before and after the transplantation, by cytokine flow cytometry. A total of 21 kidney transplant recipients (14 male, 7 female; age range: 18-66 years, mean age: 34.5 ± 9.9) who were all CMV seropositive have been evaluated in the study. Blood samples from the patients were obtained before and at the 1(st), 3(rd) and 6(th) months after transplantation. CMV seropositive healthy kidney donors (n= 20) constituted the control group. The main stages of our procedure were as follows; isolation of peripheral blood mononuclear cells from whole blood, freezing and storing of the samples, later on thawing the samples, ex vivo stimulation of lymphocytes with pooled CMV peptides and counting CMV-specific IFN- producing CD4(+) and CD8(+) T cells by flow cytometry following surface and intracellular cytokine staining. Monitoring of the viral load (CMV-DNA) was performed in 10 days intervals in the first 3 months followed by 3 week intervals until 6 months using COBAS AmpliPrep/COBAS TaqMan CMV test system (Roche Diagnostics, USA). The frequencies of pretransplant CMV-specific IFN-γ producing CD8(+) T cells in patient (3.53 ± 4.35/µl) and control (4.52 ± 5.17/µl) groups were not statistically different (p= 0.266). The difference between the number of virus-specific CD4(+) T cells in patients (8.84 ± 9.56/µl) and those in the control group (8.23 ± 11.98/µl) was at the borderline of significance (p= 0.057). The age and gender of the patients and type of antiviral prophylaxis protocols [valgancyclovir (n= 4); valacyclovir (n= 17)] did not have any significant effect on CMV-CMI (p> 0.05). Similarly, induction therapy administered to four patients did not show any effect on CMV-CMI (p> 0.05). CMV-specific immune responses of patients who received different immunosuppression protocols [tacrolimus + mycophenolate mofetil (MMF) + steroid (n= 17); cyclosporine + MMF + steroid (n= 2); mTOR inhibitor + MMF + steroid (n= 2)] were not different (p> 0.05). The number of CMV-specific CD4(+) T cells in all patients were significantly decreased in the 3rd month compared to the 1st month after the transplantation (p=0.003), indicating a relationship with the period of immunosuppressive therapy. In one of the patients who did not have CMV-specific CD4+ T-cell response but had cytotoxic T-cells (CD8(+) T= 0.6%) before transplantation, CD4(+) T-cell response have developed during monitorization (1.4%, 1.5% and 0.5% in 1st, 3rd and 6th months, respectively), and no viral reactivation was detected. Out of the two patients who had no CD4(+) and CD8(+) T cell response in the 3rd month, one of them developed low level viremia (150 copies/ml) in the 6th month. In this patient the level of CMV-CMI in the 6th month (CD4(+)T + CD8(+)T= 0.9%), have reached higher values than the values obtained before the transplantation (CD4(+) T + CD8(+) T= 0.5%). The viremia was cleared spontaneously in this patient and no antiviral therapy was required. In conclusion, our results suggested that pretransplant and posttransplant monitoring of CMV-specific T-cell responses might be helpful as well as viral load in the clinical management of CMV infection in SOT patients.

Quantitative analysis of BKV-specific CD4+ T cells before and after kidney transplantation.

BACKGROUND: BK virus (BKV) is the main infectious cause of renal allograft dysfunction. Although recent studies showed an inverse correlation between BKV-specific T-cell responses and viral load after transplantation, the importance of pre-transplant response in the process of virus reactivation has only been studied once. In this study, we aimed to determine whether pre-transplant CD4+ T-cell response can be used for prediction of BKV reactivation and BKV nephropathy (BKVN), by a method that can practically be used in routine patient monitoring. METHODS: BKV-specific CD4+ T-cell responses of 31 kidney recipients (all from live donors) were measured by an IFN-γ-enzyme-linked-immunospot (ELISPOT) method using mixture of peptides, at day 0 and +1, +3, and +6 months posttransplant. Additionally, seven other reactivation patients as another group were also analyzed. BKV viral loads in plasma were measured by real-time polymerase chain reaction (PCR). Responses of 10 healthy people were also included as controls in the analysis. RESULTS: All but one patient and all of the controls had detectable CD4+ T-cell responses. Reactivation occurred in 8 out of 31 patients. There was no significant association between pretransplant BKV-specific CD4+ T-cell responses and BKV reactivation and between BKV DNA levels and CD4+ T-cell responses. In the additional group consisting of reactivation patients, four patients who had BKVN showed negative correlation between BKV-DNA levels and BKV-specific CD4+ T-cell responses (p<0.05). One patient who developed BKVN, however, was not able to mount a similar CD4+ T-cell response to viral reactivation despite immunosuppressive reduction. CONCLUSION: Even though our cohort is small, our results may suggest that pre-transplant measurement of BKV specific CD4+ T-cell response may not be necessary, and that post-transplant monitoring, particularly during reactivation, may be more helpful in the management of the infection.