Eulalia Palma

Decrease in the percentage of peripheral blood CXCR3highCD4+ lymphocytes after renal transplantation.

INTRODUCTION Previous studies suggest that infiltration into the graft of active T cells following kidney transplantation depends on the expression of chemokines and their interaction with their T-cell receptors. However, little is known about the natural history of the expression of these molecules during the early post-transplantation phase. AIM To evaluate the percentage of CXCR3highCD4+ and CCR4highCD4+ cells, as markers of the Th1 and Th2 populations, in peripheral blood from uremic patients before transplantation and six months after maintaining an acceptable kidney graft function. MATERIAL AND METHODS Flow cytometry was used to measure CXCR3highCD4+ and CCR4highCD4+ cells from 44 consecutive patients who received a kidney transplant at our center. Measurements were made at the time of transplantation and six months later. RESULTS There was a significant reduction after transplantation in the CXCR3highCD4+/CCR4highCD4+ balance (10.68±20.28 vs. 2.01±3.15, p=0.001). Separate analysis of each subset showed a significant reduction after transplantation in CXCR3highCD4+ (2.37±2.75 vs. 1.49±2.66, p=0.010) but no difference in CCR4highCD4+ (0.83±1.01 vs. 1.01±1.12, p=0.812). CONCLUSION Prior to kidney transplantation uremic patients have an immunologic activation with Th1 polarization (studied by analyzing the CXCR3highCD4+ and CCR4highCD4+ populations) that falls after transplantation. This can be monitored with the CXCR3highCD4+ lymphocyte subset. This may help understand the pathologic mechanisms intervening in immunologic dysfunction of kidney grafts.

Survival in Southern European patients waitlisted for kidney transplant after graft failure: A competing risk analysis

Background Whether patients waitlisted for a second transplant after failure of a previous kidney graft have higher mortality than transplant-näive waitlisted patients is uncertain. Methods We assessed the relationship between a failed transplant and mortality in 3851 adult KT candidates, listed between 1984–2012, using a competing risk analysis in the total population and in a propensity score-matched cohort. Mortality was also modeled by inverse probability weighting (IPTW) competing risk regression. Results At waitlist entry 225 (5.8%) patients had experienced transplant failure. All-cause mortality was higher in the post-graft failure group (16% vs. 11%; P = 0.033). Most deaths occurred within three years after listing. Cardiovascular disease was the leading cause of death (25.3%), followed by infections (19.3%). Multivariate competing risk regression showed that prior transplant failure was associated with a 1.5-fold increased risk of mortality (95% confidence interval [CI], 1.01–2.2). After propensity score matching (1:5), the competing risk regression model revealed a subhazard ratio (SHR) of 1.6 (95% CI, 1.01–2.5). A similar mortality risk was observed after the IPTW analysis (SHR, 1.7; 95% CI, 1.1–2.6). Conclusions Previous transplant failure is associated with increased mortality among KT candidates after relisting. This information is important in daily clinical practice when assessing relisted patients for a retransplant.

Increase in CD8+CD158a+ T Cells in Kidney Graft Blood is Associated with Better Renal Function

BACKGROUND Studies of liver and heart transplant patients have shown a gradual reconstruction of the CD8 KIR2D+ T cell subpopulations, measured in peripheral blood (PB), associated with better graft acceptance. The kinetics of these populations in kidney transplants, however, is still poorly understood, especially given the lack of studies of blood samples from the kidney graft. MATERIAL AND METHODS Flow cytometry was used to measure CD8+CD158a/b/e T cells in 69 kidney transplant patients who had stable renal function during follow-up. Measurements were made at 3, 6, and 12 months post-transplantation in graft capillary blood extracted by fine needle aspiration puncture (FNAP) and in PB. RESULTS No progressive increase was found in the PB subpopulations. However, the CD8+CD158a+ subsets increased significantly at 12 months in the graft blood versus the PB samples (3.91±4.59 vs. 2.84±4.71; p=0.021). The ratio of the percentage of CD8+CD158a+ cells in graft blood compared to PB at 12 months was associated with better renal function in those patients with a ratio ≥3 (66.6±14.53 vs. 55.7±21.6; p=0.032). CONCLUSIONS An increased ratio of CD8+CD158a+ cells, measured by flow cytometry, between graft blood and PB was associated with improved renal function.

Effect of Steroid Withdrawal on the Appearance of De Novo Donor-Specific HLA Antibodies in Kidney Transplant Recipients: A Prospective, Randomized, Controlled, Parallel Group Study. Preliminary Results

Introduction Steroids represent one of the mainstays of immunosuppression after kidney transplant (KT). Steroid withdrawal reduces metabolic and cardiovascular complications, but whether it increases the risk of acute rejection and the generation of donor-specific anti-HLA antibodies (DSA) is currently undetermined. Materials and Methods In a controlled clinical trial (NCT02284464), a total of 176 KT patients with low immunological risk were recruited to randomly receive either conventional triple immunosuppression: steroids, TAC and MMF versus steroid withdrawal at the third post-KT month. We compared the incidence of de novo DSA, determined by Luminex Mixed and Luminex Single Antigen (One Lambda®), and its impact on graft histology in patients with steroid withdrawal at the 3 post-KT month (after a protocol biopsy) versus patients who continue to receive conventional triple immunosuppression. Results So far, 68 patients have been randomized (34 per group), with no significant differences in the clinical and demographic characteristics between the groups. The intermediate analysis in those patients who had completed one year of follow-up (n=28) showed no significant differences in the formation of DSA (0% vs. 0%), nor was there rejection in those patients in whom prednisone was withdrawn after randomization. Patients with triple therapy showed a trend toward better renal function compared to those without steroids at the first post-KT year (1.29±0.25 vs. 1.56±0.42 mg/dL, P=0.088). HbA1c levels were similar between both group at the first post-KT year (5.79±0.59 vs. 5.68±0.81%, P=0.734). Conclusion The preliminary results show that steroid withdrawal at the 3 month post-KT seems safe when assessing the appearance of rejection and formation of DSA compared to the patients who continued to receive conventional triple immunosuppression. Spanish Ministry of Economy and Competitiveness (MINECO) (grant ICI14/00016) from the Instituto de Salud Carlos III co-funded by the Fondo Europeo de Desarrollo Regional–FEDER, RETICS (REDINREN RD12/0021/0015, RD16/0009/0006, RD16/0009/0003, RD16/0009/0030, RD16/0009/0031).

Analysis of CCR4high CD4+ in Kidney Graft Blood After Steroid Withdrawal: A Prospective, Randomized, Controlled, Parallel Group Study. Preliminary Results

Introduction Steroids represent a mainstay of immunosuppression after kidney transplant. The infiltration into the graft of active T cells following KT depends on the expression of chemokines and their interaction with their T-cell receptors. However, the natural history of the expression of these molecules in patients who undergo steroid withdrawal after transplant is unknown. Materials and Methods In a controlled clinical trial (NCT02284464), a total of 176 KT patients with low immunological risk were recruited to randomly receive either conventional triple immunosuppression: steroids, TAC and MMF (Group A) versus steroid withdrawal at the 3 post-KT month (Group B). We compared the evolution of CCR4highCD4+ and CXCR3highCD4+ lymphocyte subpopulations in graft blood (GB) extracted by fine needle aspiration puncture determined by flow cytometry in patients after steroid withdrawal at the 3 month post-KT versus patients who continue to receive conventional triple immunosuppression. Measurements were made at 3 (baseline) and 6 months post-KT in GB and in peripheral blood (PB). Results So far, 68 patients have been randomized (34 in each group). There were no significant differences in the clinical and demographic characteristics between the groups at baseline. The first analysis (at 3 months) in those patients who had completed 6 months of follow-up (Group A: n=13; Group B: n=15) showed a significant increase in the CCR4highCD4 subpopulations in GB versus PB in both groups. However, at six months a significant increase in GB versus PB was only seen in Group A. There were no significant differences in the CXCR3highCD4+ lymphocyte subpopulation at the third or sixth month between GB and PB in either group (Table). Table. No title available. Conclusion These preliminary results could suggest a possible effect of prednisone that would favor the recruitment of CCR4highCD4+ cells into the renal graft. Spanish Ministry of Economy and Competitiveness (MINECO) (grant ICI14/00016) from the Instituto de Salud Carlos III co-funded by the Fondo Europeo de Desarrollo Regional–FEDER, RETICS (REDINREN RD12/0021/0015, RD16/0009/0006).

Peripheral Vascular Disease and Death in Southern European Kidney Transplant Candidates: A Competing Risk Modeling Approach

Background The association between peripheral vascular disease (PVD) and survival among kidney transplant (KT) candidates is uncertain. Methods We assessed 3851 adult KT candidates from the Andalusian Registry between 1984 and 2012. Whereas 1975 patients received a KT and were censored, 1876 were on the waiting list at any time. Overall median waitlist time was 21.2 months (interquartile range, 11-37.4). We assessed the association between PVD and mortality in waitlisted patients using a multivariate Cox regression model, with a competing risk approach as a sensitivity analysis. Results Peripheral vascular disease existed in 308 KT candidates at waitlist entry. The prevalence of PVD among nondiabetic and diabetic patients was 4.5% and 25.3% (P < 0.0001). All-cause mortality was higher in candidates with PVD (45% vs 21%; P < 0.0001). Among patients on the waiting list (n = 1876) who died (n = 446; 24%), 272 (61%) died within 2 years after listing. Cumulative incidence of all-cause mortality at 2 years in patients with and without PVD was 23% and 6.4%, respectively (P < 0.0001); similar differences were observed in patients with and without diabetes. By competing risk models, PVD was associated with a 1.9-fold increased risk of mortality (95% confidence interval [95% CI], 1.4-2.5). This association was stronger in waitlisted patients without cardiac disease (subhazard ratio, 2.2; 95% CI, 1.6-3.1) versus those with cardiac disorders (subhazard ratio, 1.5; 95% CI, 0.9-2.5). No other significant interactions were observed. Similar results were seen after excluding diabetics. Conclusions Peripheral vascular disease is a strong predictor of mortality in KT candidates. Identification of PVD at list entry may contribute to optimize targeted therapeutic interventions and help prioritize high-risk KT candidates.

Vascular Damage and Kidney Transplant Outcomes: An Unfriendly and Harmful Link

Abstract Kidney transplant (KT) is the treatment of choice for most patients with chronic kidney disease, but this has a high cardiovascular mortality due to traditional and nontraditional risk factors, including vascular calcification. Inflammation could precede the appearance of artery wall lesions, leading to arteriosclerosis and clinical and subclinical atherosclerosis in these patients. Additionally, mineral metabolism disorders and activation of the renin‐angiotensin system could contribute to this vascular damage. Thus, understanding the vascular lesions that occur in KT recipients and the pathogenic mechanisms involved in their development could be crucial to optimize the therapeutic management and outcomes in survival of this population. This review focuses on the following issues: (1) epidemiological data framing the problem; (2) atheromatosis in KT patients: subclinical and clinical atheromatosis, involving ischemic heart disease, congestive heart failure, stroke and peripheral vascular disease; (3) arteriosclerosis and vascular calcifications; and (4) potential pathogenic mechanisms and their therapeutic targets.