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The long-term effect of protection by two doses of SARS-CoV-2 vaccination in patients receiving chronic intermittent hemodialysis (CIHD) is an urging question. We investigated the humoral and cellular immune response of 42 CIHD patients who had received two doses of SARS-CoV-2 vaccine, and again after a booster vaccine with mRNA-1273 six months later. We measured antibody levels and SARS-CoV-2-specific surrogate neutralizing antibodies (SNA). Functional T cell immune response to vaccination was assessed by quantifying interferon-γ (IFN-γ) and IL-2 secreting T cells specific for SARS-CoV-2 using an ELISpot assay. Our data reveal a moderate immune response after the second dose of vaccination, with significantly decreasing SARS-CoV-2-specific antibody levels and less than half of the study group showed neutralizing antibodies six months afterwards. Booster vaccines increased the humoral response dramatically and led to a response rate of 89.2% for antibody levels and a response rate of 94.6% for SNA. Measurement in a no response/low response (NR/LR) subgroup of our cohort, which differed from the whole group in age and rate of immunosuppressive drugs, indicated failure of a corresponding T cell response after the booster vaccine. We strongly argue in favor of a regular testing of surrogate neutralizing antibodies and consecutive booster vaccinations for CIHD patients to provide a stronger and persistent immunity.
With the introduction of the virtual allocation crossmatch in the Eurotransplant (ET) region in 2023, the determination of unacceptable antigen mismatches (UAM) in kidney transplant recipients is of utmost importance for histocompatibility laboratories and transplant centers. Therefore, a joined working group of members from the German Society for Immunogenetics (Deutsche Gesellschaft für Immungenetik, DGI) and the German Transplantation Society (Deutsche Transplantationsgesellschaft, DTG) revised and updated the previous recommendations from 2015 in light of recently published evidence. Like in the previous version, a wide range of topics is covered from technical issues to clinical risk factors. This review summarizes the evidence about the prognostic value of contemporary methods for HLA antibody detection and identification, as well as the impact of UAM on waiting time, on which these recommendations are based. As no clear criteria could be determined to differentiate potentially harmful from harmless HLA antibodies, the general recommendation is to assign all HLA against which plausible antibodies are found as UAM. There is, however, a need for individualized solutions for highly immunized patients. These revised recommendations provide a list of aspects that need to be considered when assigning UAM to enable a fair and comprehensible procedure and to harmonize risk stratification prior to kidney transplantation between transplant centers.
Cadmium-mediated toxicity of cultured proximal tubule (PT) cells is associated with increased production of reactive oxygen species (ROS) and apoptosis. We found that cadmium-dependent apoptosis (Hoechst 33342 and annexin V assays) decreased with prolonged CdCl(2) (10 microM) application (controls: 2.4 +/- 1.6%; 5 h: +5.1 +/- 2.3%, 20 h: +5.7 +/- 2.5%, 48 h: +3.3 +/- 1.0% and 72 h: +2.1 +/- 0.4% above controls), while cell proliferation was not affected. Reduction of apoptosis correlated with a time-dependent up-regulation of the drug efflux pump multidrug resistance P-glycoprotein (mdr1) in cadmium-treated cells ( approximately 4-fold after 72 h), as determined by immunoblotting with the monoclonal antibody C219 and measurement of intracellular accumulation of the fluorescent probe calcein +/- the mdr1 inhibitor PSC833 (0.5 microM). When mdr1 inhibitors (PSC833, cyclosporine A, verapamil) were transiently added to cells with mdr1 up-regulation by pretreatment for 72 h with cadmium, cadmium-induced apoptosis increased significantly and to a percentage similar to that obtained in cells with no mdr1 up-regulation (72-h cadmium: 5.2 +/- 0.9% versus 72-h cadmium + 1-h PSC833: 7.2 +/- 1.4%; p < or = 0.001). Cadmium-induced apoptosis and mdr1 up-regulation depended on ROS, since co-incubation with the ROS scavengers N-acetylcysteine (15 mM) or pyrrolidine dithiocarbamate (0.1 mM) abolished both responses. Moreover, cadmium- and ROS-associated mdr1 up-regulation was linked to activation of the transcription factor NF-kappaB; N-acetylcysteine, pyrrolidine dithiocarbamate, and the IkappaB-alpha kinase inhibitor Bay 11-7082 (20 microM) prevented both, mdr1 overexpression and degradation of the inhibitory NF-kappaB subunit, IkappaB-alpha, induced by cadmium. The data show that 1) cadmium-mediated apoptosis in PT cells is associated with ROS production, 2) ROS increase mdr1 expression by a process involving NF-kappaB activation, and 3) mdr1 overexpression protects PT cells against cadmium-mediated apoptosis. These data suggest that mdr1 up-regulation, at least in part, provides anti-apoptotic protection for PT cells against cadmium-mediated stress.
Background: High sensitivity cardiac troponin T (hs-cTnT) and NT-pro-brain natriuretic peptide (NT-pro BNP) are often elevated in chronic kidney disease (CKD) and associated with both cardiovascular remodeling and outcome. Relationship between these biomarkers and quantitative imaging measures of myocardial fibrosis and edema by T1 and T2 mapping remains unknown. Methods: Consecutive patients with established CKD and estimated glomerular filtration rate (eGFR) < 59 ml/min/1.73 m2 (n = 276) were compared to age/sex matched patients with eGFR ≥ 60 ml/min/1.73 m2 (n = 242) and healthy controls (n = 38). Comprehensive cardiovascular magnetic resonance (CMR) with native T1 and T2 mapping, myocardial ischemia and scar imaging was performed with venous sampling immediately prior to CMR. Results: Patients with CKD showed significant cardiac remodeling in comparison with both healthy individuals and non-CKD patients, including a stepwise increase of native T1 and T2 (p < 0.001 between all CKD stages). Native T1 and T2 were the sole imaging markers independently associated with worsening CKD in patients [B = 0.125 (95% CI 0.022–0.235) and B = 0.272 (95% CI 0.164–0.374) with p = 0.019 and < 0.001 respectively]. At univariable analysis, both hs-cTnT and NT-pro BNP significantly correlated with native T1 and T2 in groups with eGFR 30–59 ml/min/1.73 m2 and eGFR < 29 ml/min/1.73 m2 groups, with associations being stronger at lower eGFR (NT-pro BNP (log transformed, lg10): native T1 r = 0.43 and r = 0.57, native T2 r = 0.39 and r = 0.48 respectively; log-transformed hs-cTnT(lg10): native T1 r = 0.23 and r = 0.43, native T2 r = 0.38 and r = 0.58 respectively, p < 0.001 for all, p < 0.05 for interaction). On multivariable analyses, we found independent associations of native T1 with NT-pro BNP [(B = 0.308 (95% CI 0.129–0.407), p < 0.001 and B = 0.334 (95% CI 0.154–0.660), p = 0.002 for eGFR 30–59 ml/min/1.73 m2 and eGFR < 29 ml/min/1.73 m2, respectively] and of T2 with hs-cTnT [B = 0.417 (95% CI 0.219–0.650), p < 0.001 for eGFR < 29 ml/min/1.73 m2]. Conclusions: We demonstrate independent associations between cardiac biomarkers with imaging markers of interstitial expansion, which are CKD-group specific. Our findings indicate the role of diffuse non-ischemic tissue processes, including excess of myocardial fluid in addition to diffuse fibrosis in CKD-related adverse remodeling.
CD4+ T cell lymphopenia predicts mortality from Pneumocystis pneumonia in kidney transplant patients
(2020)
Background: Pneumocystis jirovecii pneumonia (PcP) remains a life-threatening opportunistic infection after solid organ transplantation, even in the era of Pneumocystis prophylaxis. The association between risk of developing PcP and low CD4+ T cell counts has been well established. However, it is unknown whether lymphopenia in the context of post-renal transplant PcP increases the risk of mortality. Methods: We carried out a retrospective analysis of a cohort of kidney transplant patients with PcP (n = 49) to determine the risk factors for mortality associated with PcP. We correlated clinical and demographic data with the outcome of the disease. For CD4+ T cell counts, we used the Wilcoxon rank sum test for in-hospital mortality and a Cox proportional-hazards regression model for 60-day mortality. Results: In univariate analyses, high CRP, high neutrophils, CD4+ T cell lymphopenia, mechanical ventilation, and high acute kidney injury network stage were associated with in-hospital mortality following presentation with PcP. In a receiver-operator characteristic (ROC) analysis, an optimum cutoff of ≤200 CD4+ T cells/µL predicted in-hospital mortality, CD4+ T cell lymphopenia remained a risk factor in a Cox regression model. Conclusions: Low CD4+ T cell count in kidney transplant recipients is a biomarker for disease severity and a risk factor for in-hospital mortality following presentation with PcP.
In Eurotransplant kidney allocation system (ETKAS), candidates can be considered unlimitedly for repeated re‐transplantation. Data on outcome and benefit are indeterminate. We performed a retrospective 15‐year patient and graft outcome data analysis from 1464 recipients of a third or fourth or higher sequential deceased donor renal transplantation (DDRT) from 42 transplant centers. Repeated re‐DDRT recipients were younger (mean 43.0 vs. 50.2 years) compared to first DDRT recipients. They received grafts with more favorable HLA matches (89.0% vs. 84.5%) but thereby no statistically significant improvement of patient and graft outcome was found as comparatively demonstrated in 1st DDRT. In the multivariate modeling accounting for confounding factors, mortality and graft loss after 3rd and ≥4th DDRT (P < 0.001 each) and death with functioning graft (DwFG) after 3rd DDRT (P = 0.001) were higher as compared to 1st DDRT. The incidence of primary nonfunction (PNF) was also significantly higher in re‐DDRT (12.7%) than in 1st DDRT (7.1%; P < 0.001). Facing organ shortage, increasing waiting time, and considerable mortality on dialysis, we question the current policy of repeated re‐DDRT. The data from this survey propose better HLA matching in first DDRT and second DDRT and careful selection of candidates, especially for ≥4th DDRT.
Mesenchymal stromal/stem cells (MSCs) are immature multipotent cells, which represent a rare population in the perivascular niche within nearly all tissues. The most abundant source to isolate MSCs is adipose tissue. Currently, perirenal adipose tissue is rarely described as the source of MSCs. MSCs were isolated from perirenal adipose tissue (prASCs) from patients undergoing tumor nephrectomies, cultured and characterized by flow cytometry and their differentiation potential into adipocytes, chondrocytes, osteoblasts and epithelial cells. Furthermore, prASCs were stimulated with lipopolysaccharide (LPS), lipoteichoic acid (LTA) or a mixture of cytokines (cytomix). In addition, prASC susceptibility to human cytomegalovirus (HCMV) was investigated. The expression of inflammatory readouts was estimated by qPCR and immunoassay. HCMV infection was analyzed by qPCR and immunostaining. Characterization of cultured prASCs shows the cells meet the criteria of MSCs and prASCs can undergo trilineage differentiation. Cultured prASCs can be induced to differentiate into epithelial cells, shown by cytokeratin 18 expression. Stimulation of prASCs with LPS or cytomix suggests the cells are capable of initiating an inflammation-like response upon stimulation with LPS or cytokines, whereas, LTA did not induce a significant effect on the readouts (ICAM-1, IL-6, TNFα, MCP-1 mRNA and IL-6 protein). HCMV broadly infects prASCs, showing a viral load dependent cytopathological effect (CPE). Our current study summarizes the isolation and culture of prASCs, clearly characterizes the cells, and demonstrates their immunomodulatory potential and high permissiveness for HCMV
Background: Patients with chronic kidney disease (CKD) have considerable cardiovascular morbidity and mortality. Aortic stiffness is an independent predictor of cardiovascular risk and related to left ventricular remodeling and heart failure. Myocardial fibrosis is the pathophysiological hallmark of the failing heart.
Methods and results: An observational study of consecutive CKD patients (n = 276) undergoing comprehensive clinical cardiovascular magnetic resonance imaging. The relationship between aortic stiffness, myocardial fibrosis, left ventricular remodeling and the severity of chronic kidney disease was examined. Compared to age-gender matched controls with no known kidney disease (n = 242), CKD patients had considerably higher myocardial native T1 and central aortic PWV (p ≪ 0.001), as well as abnormal diastolic relaxation by E/e′ (mean) by echocardiography (p ≪ 0.01). A third of all patients had LGE, with similar proportions for the presence and the (ischaemic and non-ischaemic) pattern between the groups. PWV was strongly associated with and age, NT-proBNP and native T1 in both groups, but not with LGE presence or type; the associations were amplified in severe CKD stages. In multivariate analyses, PWV was independently associated with native T1 in both groups (p ≪ 0.01) with near two-fold increase in adjusted R2 in the presence of CKD (native T1 (10 ms) R2, B(95%CI) CKD vs. non-CKD 0.28, 0.2(0.15–0.25) vs. 0.18, 0.1(0.06–0.15), p ≪ 0.01).
Conclusions: Aortic stiffness and interstitial myocardial fibrosis are interrelated; this association is accelerated in the presence of CKD, but independent of LGE. Our findings reiterate the significant contribution of CKD-related factors to the pathophysiology of cardiovascular remodeling.
This is a randomized trial (ATHENA study) in de novo kidney transplant patients to compare everolimus versus mycophenolic acid (MPA) with similar tacrolimus exposure in both groups, or everolimus with concomitant tacrolimus or cyclosporine (CsA), in an unselected population. In this 12-month, multicenter, open-label study, de novo kidney transplant recipients were randomized to everolimus with tacrolimus (EVR/TAC), everolimus with CsA (EVR/CsA) or MPA with tacrolimus (MPA/TAC), with similar tacrolimus exposure in both groups. Non-inferiority of the primary end point (estimated glomerular filtration rate [eGFR] at month 12), assessed in the per-protocol population of 338 patients, was not shown for EVR/TAC or EVR/CsA versus MPA/TAC. In 123 patients with TAC levels within the protocol-specified range, eGFR outcomes were comparable between groups. The mean increase in eGFR during months 1 to 12 post-transplant, analyzed post hoc, was similar with EVR/TAC or EVR/CsA versus MPA/TAC. The incidence of treatment failure (biopsy proven acute rejection, graft loss or death) was not significant for EVR/TAC but significant for EVR/CsA versus MPA/TAC. Most biopsy-proven acute rejection events in this study were graded mild (BANFF IA). There were no differences in proteinuria between groups. Cytomegalovirus and BK virus infection were significantly more frequent with MPA/TAC. Thus, everolimus with TAC or CsA showed comparable efficacy to MPA/TAC in de novo kidney transplant patients. Non-inferiority of renal function, when pre-specified, was not shown, but the mean increase in eGFR from month 1 to 12 was comparable to MPA/TAC.
Background: Kidney transplant recipients (KTR) reflect a high-risk population for coronary artery disease (CAD). CAD is the most common cause for morbidity and mortality in this population. However, only few data are available on the favourable revascularization strategy for these patients as they were often excluded from studies and not mentioned in guidelines.
Methods: This retrospective single-centre study includes patients with a history of kidney transplantation undergoing myocardial revascularization for multivessel or left main CAD by either percutaneous coronary intervention (PCI, n = 27 patients) or coronary artery bypass grafting (CABG, n = 24 patients) at University Hospital Frankfurt, Germany, between 2005 and 2015.
Results: In-hospital mortality was higher in the CABG group (20.8% vs. 14.8% PCI group; p = 0.45). In Kaplan-Meier analysis, one-year-survival showed better outcome in the PCI group (85.2% vs. 75%). After four years, outcome was comparable between both strategies (PCI 66.5% vs. CABG 70.8%; log-rank p = 0.94).
Acute kidney injury (AKI), classified by Acute Kidney Injury Network, was observed more frequently after CABG (58.3% vs. 18.5%; p < 0.01). After one year, graft survival was 95.7% in the PCI group and 94.1% in the CABG group. Four year follow-up showed comparable graft survival in both groups (76.8% PCI and 77.0% CABG; p = 0.78).
Conclusion: In this retrospective single-centre study of KTR requiring myocardial revascularization, PCI seems to be superior to CABG with regard to in-hospital mortality, acute kidney injury and one-year-survival. To optimise treatment of these high-risk patients, larger-scaled studies are urgently warranted.