Exposure to tacrolimus trough levels below 6 ng/ml during the first year is associated with inferior kidney graft survival.

BACKGROUND: Accumulating data indicate that sub-therapeutic levels of tacrolimus are associated with long-term kidney graft loss. However, elevated doses increase the risk of infection and drug toxicity, which also threaten graft and patient longevity. We sought to determine the minimal tacrolimus level required to maintain graft survival. METHODS: We conducted a single-center historical cohort study. The first-year post-transplant exposure time was calculated for each of the five tacrolimus trough level intervals. This measure was adjusted to the exposure time below a given interval level, allowing us to define the threshold for the optimal tacrolimus level as the upper limit of the interval. We then determined the association between the adjusted exposure time at each tacrolimus level interval and our primary outcome, death-censored graft loss. RESULTS: One thousand four hundred and seventeen patients with a median follow-up of 5.3 years were included in the final cohort. The tacrolimus level interval of 5-6 ng/ml was the highest interval, which demonstrated a statistically significant association between adjusted exposure time and increased risk of graft loss (HR 1.58, per log days, p = .002). Cumulative exposure time above 14 days with a tacrolimus level below 6 ng/ml was associated with an increased rate of graft loss in most studied subgroups, except for recipients with pre transplant diabetes. CONCLUSIONS: Maintaining tacrolimus levels above 6 ng/ml during the first-year post-transplant might improve kidney graft survival.

Second pregnancy following kidney transplantation is not associated with an increased risk of graft loss in a single center retrospective cohort study.

INTRODUCTION: Previous studies on first pregnancy following kidney transplantation (KT) show no association with decreased graft survival. This study examined patients with multiple gestations compared to a single pregnancy following KT and evaluated the risk of graft function deterioration. METHODS: A retrospective cohort study on fertile female kidney transplant recipients (KTRs) from Rabin Medical Center between January 2001 and December 2017 was performed. Data were collected on patients' comorbidities, pregnancy complications, graft loss, mortality, and lab results. Time-varying COX analysis was performed - second pregnancy being the time-related variable. RESULTS: Fifty-two KTRs split into 30 single pregnancy and 22 multiple pregnancy patients following KT. Single pregnancy patients were older during their first pregnancy and had a higher caesarian section rate. During a median follow-up period of 5.6 years, multiple pregnancies, compared to a single pregnancy, were not associated with an increased rate of graft loss. No significant difference was seen between first and second pregnancy in gestational age, birth weight, graft function, and proteinuria rates. CONCLUSIONS: Second pregnancy following KT was not shown to be associated with a decreased graft survival. In addition, obstetrical, maternal, and fetal complication rates are not increased in second compared to first pregnancy following KT.

Immune Response to Third Dose BNT162b2 COVID-19 Vaccine Among Kidney Transplant Recipients-A Prospective Study.

Immune response to two SARS-CoV-2 mRNA vaccine doses among kidney transplant recipients (KTRs) is limited. We aimed to evaluate humoral and cellular response to a third BNT162b2 dose. In this prospective study, 190 KTRs were evaluated before and ∼3 weeks after the third vaccine dose. The primary outcomes were anti-spike antibody level >4160 AU/ml (neutralization-associated cutoff) and any seropositivity. Univariate and multivariate analyses were conducted to identify variables associated with antibody response. T-cell response was evaluated in a subset of participants. Results were compared to a control group of 56 healthcare workers. Among KTRs, we found a seropositivity rate of 70% (133/190) after the third dose (37%, 70/190, after the second vaccine dose); and 27% (52/190) achieved levels above 4160 AU/ml after the third dose, compared to 93% of controls. Variables associated with antibody response included higher antibody levels after the second dose (odds ratio [OR] 30.8 per log AU/ml, 95% confidence interval [CI]11-86.4, p < 0.001); and discontinuation of antimetabolite prior to vaccination (OR 9.1,95% CI 1.8-46.5, p = 0.008). T-cell response was demonstrated in 13% (7/53). In conclusion, third dose BNT162b2 improved immune response among KTRs, however 30% still remained seronegative. Pre-vaccination temporary immunosuppression reduction improved antibody response.

Association of the combination of time-weighted variability of tacrolimus blood level and exposure to low drug levels with graft survival after kidney transplantation.

Background: The variability of tacrolimus blood levels has been shown to be associated with inferior graft survival. However, the effect of variability during the early post-transplantation period has not been evaluated. We sought to evaluate the association between time-weighted variability in the early post-transplantation period and graft survival. We also explored the interaction between drug level variability and exposure to inadequate drug levels. Methods: This retrospective cohort study included all patients who underwent kidney transplantation in the Rabin Medical Center and were treated with tacrolimus. Time-weighted coefficient of variability (TWCV) was defined as time-weighted standard deviation divided by the mean drug level. Univariate and multivariate Cox proportional hazard model was used with the primary outcome of patients and graft survival. Results: The study population included 803 patients who underwent kidney transplantation between 1 January 2000 and 29 September 2013. The high tertile of TWCV of tacrolimus blood levels was associated with reduced graft survival by univariate and multivariate analyses [hazard ratio (HR) 1.69, 95% confidence interval (CI) 1.14-2.53, P = 0.01 and HR 1.74, 95% CI 1.14-2.63, P = 0.01, respectively]. The interaction between high TWCV and exposure to inadequately low drug levels was significantly associated with reduced survival (P = 0.004), while the interaction between TWCV and high drug blood levels was not. One hundred and thirty patients (16.2%) had the combination of high TWCV and exposure to low drug values (<5 ng/mL). These patients had reduced graft survival by univariate and multivariate analyses (HR 2.42, 95% CI 1.57-3.74, P < 0.001 and HR 2.6, 95% CI 1.65-4.11, P < 0.001, respectively). Conclusions: The combination of high TWCV and exposure to low drug levels might identify high-risk patients in the early post-transplantation period.

The incidence of post-transplant cancer among kidney transplant recipients is associated with the level of tacrolimus exposure during the first year after transplantation.

PURPOSE: Immunosuppressive therapy plays a major role in the development of post-transplant cancer. In this nested case-control study of kidney transplant recipients (KTRs), we investigated whether the incidence of post-transplant cancer is associated with the level of tacrolimus exposure over time. METHODS: We screened the Rabin Medical Center database for adults who received kidney transplants between 2001 and 2014 and developed post-transplant cancer (excluding basal and squamous cell skin cancers). They were matched against KTRs without cancer. All patients received a maintenance immunosuppressive treatment with tacrolimus, mycophenolate mofetil and corticosteroids. The degree of exposure to tacrolimus was estimated as the time-weighted average (tTWA) value of tacrolimus blood levels. The tTWA was calculated as the area under the curve divided by time at 1, 6, and 12 months after transplantation and at time of cancer diagnosis. RESULTS: Thirty-two cases were matched against 64 controls. tTWA values above 11 ng/mL at 6 and 12 months after transplantation were associated with odds ratio (OR) of 3.1 (95% CI 1.1-9) and 11.7 (95% CI = 1.3-106), respectively, for post-transplant cancer; and with OR of 5.2 (95% CI 1.3-20.5) and 14.1 (95% CI = 1.5-134.3), respectively, for cancer diagnosed more than 3 years after transplantation. CONCLUSION: Exposure to a tacrolimus time-weighted average level above 11 ng/mL at 6 or 12 months after kidney transplantation is associated with an increased risk of developing cancer.

Cytomegalovirus-negative kidney transplant recipients are at an increased risk for malignancy after kidney transplantation.

BACKGROUND: The effect of cytomegalovirus (CMV) serology status on malignancy risk in kidney transplanted patients is not clear yet. METHODS: In a nested case-control study, CMV serology status was compared between patients with a malignancy and 2:1 matched control patients without a malignancy. In a cohort study, the hazard of malignancy was compared between patients that were CMV-negative but had a CMV-positive donor and other patients, using Cox analysis. RESULTS: Fifty-two of 599 patients transplanted in our center between 2001 and 2014 developed a malignancy. Nine (17.3%) of the 52 patients that developed cancer were CMV-negative but had a-CMV-positive donor compared with 6 (5.8%) of the 104 matched control patients (odd ratio 3.42, 95% confidence interval [CI] 1.15-10.2, P=.021). By univariate Cox model, there was a trend toward increased cancer risk in CMV-negative patients with a positive donor (hazard ratio [HR] 1.95, 95% CI 0.95-4.0, P=.07), but after adjusting for multiple covariates, CMV-negative status was significantly associated with increased risk of cancer (HR 2.55, 95% CI 1.23-5.26; P=.012). CONCLUSIONS: CMV-negative patients that had a CMV-positive donor were found to have a higher risk of malignancy after kidney transplantation.

The association between hydrochlorothiazide use and non-melanoma skin cancer in kidney transplant recipients.

Background: hydrochlorothiazide (HCTZ) diuretics were correlated with an increased risk of non-melanoma skin cancer (NMSC) and melanoma in the general population. Information is a scarce regarding this effect in kidney transplant recipients who are at increased risk of skin malignancies under immunosuppression. Methods: Single-center retrospective analysis of adult kidney transplant recipients between 1 January 2010 and 31 December 2015. The primary outcome of the study was the first diagnosis of skin cancer that was removed and pathologically analyzed. Exposure to thiazides was defined as HCTZ use daily for at least one year at a dose of 12.5 mg. Results: Among 520 kidney transplant recipients, 50 (9.4%) were treated with HCTZ. During a median follow-up of 9.8 years, 67 patients underwent surgical removal and pathological analysis of at least one skin cancer. Exposure to HCTZ during the 3 years following transplantation was associated with an increased risk of skin cancer (P = 0.004). In a multivariate model, there was a significant association between HCTZ exposure and NMSC (HR 2.54, 95%CI 1.26-5.15, P = 0.007). There was a higher rate of basal cell carcinoma with HCTZ exposure, according to both univariate and multivariate analyses (HR 2.61, 95%CI 1.06-6.43, P = 0.037) and (HR 3.03, 95%CI 1.22-7.55, P = 0.017, respectively). However, no significant association was observed between HCTZ exposure and squamous cell carcinoma. Conclusions: These findings suggest a benefit of increased frequency of dermatologist inspection in kidney transplant recipients receiving HCTZ especially in increased ultraviolet exposure area.

Longevity of Humoral Response Six Months Following BNT162b2 Vaccine in Dialysis Patients.

Background: End-stage kidney disease substantially increases the risk of severe COVID-19. However, despite early robust immunogenicity of the mRNA-SARS-CoV-2 vaccination in patients with hemodialysis, the longevity of humoral response in this high-risk population is still unknown. Methods: A prospective cohort study aimed to evaluate the longevity of serologic response in patients with hemodialysis, compared with a control group, 6 months following the second dose of the BNT162b2 vaccine. We assessed antibody response by quantitative measurement of IgG antibodies against the receptor-binding domain of the Spike protein (anti-S1-RBD IgG). Study outcomes were defined as a seropositivity rate and log-transformed anti-S1-RBD IgG levels at 6 months, and the change in antibody levels between 3 and 6 months. Findings: The cohort included 104 patients with hemodialysis and 84 controls. At a median time of 184 days (IQR, 183-188) following the second dose of the vaccine, 83/104 (79.8%) patients with hemodialysis maintained seropositivity for the anti-S1-RBD IgG level compared to 83/84 (98.8%) in the control group (p < 0.001). The log-transformed antibody level was significantly lower in the hemodialysis group (2.23 ± 0.39 log AU/ml vs. 2.69 ± 0.65 log AU/ml, respectively, p < 0.001). Older age and hypoalbuminemia were the only variables that were found to be associated with reduced log-transformed antibody levels in univariate and multivariate analysis. There was no interaction between dialysis status and an antibody-level decline rate (p = 0.972). Conclusion: Among patients with hemodialysis, a seropositivity rate and anti-S1-RBD antibody titers were substantially reduced compared with a control group, at 6 months following the second dose of the BNT162b2 vaccine. These findings support the prioritization of patients with hemodialysis for a third "booster" dose.

SARS-CoV-2 antibody dynamics among kidney transplant recipients 3 months after BNT162b2 vaccination: a prospective cohort study.

Data regarding immunogenicity of mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines among kidney transplant recipients in the months following vaccination are lacking. We aimed to investigate humoral immune response at 3-4 months post-vaccination among a cohort of kidney transplant recipients, compared with a control group of dialysis patients. Anti-spike antibodies were tested at 1 and 3-4 months after vaccination. Of 259 kidney transplant recipients tested at a median time of 110 days from second vaccine dose, 99 (38%) were seropositive, compared with 83% (101/122) of control patients. Younger age, better renal function and lower immunosuppression levels were associated with seropositivity. A total of 14% (13/94) of participants seropositive at 1 month became seronegative at follow-up and 11% (18/165) became seropositive. The latter were mainly individuals with higher antibody levels at 1 month. Antibody levels at 3-4 months were significantly reduced in both study groups, although the decline was more pronounced in the control group. Kidney transplant recipients present poor antibody response to mRNA SARS-CoV-2 vaccination, with only 38% seropositive at 3-4 months. Nevertheless, the decay in antibody response over time is modest, and some patients may present delayed response, reaching adequate antibody levels at 3-4 months. Low seropositivity rates in this group call for investigating other immunization strategies.

Ionizing radiation up-regulates telomerase activity in cancer cell lines by post-translational mechanism via ras/phosphatidylinositol 3-kinase/Akt pathway.

PURPOSE: Telomerase is considered currently as a hallmark of cancer, and its inhibition is expected to become an important anticancer modality. In contrast to abundant data concerning the effect of cytotoxic drugs on telomerase activity (TA), there is scant information on the effect of radiation on telomerase. The mechanism of telomerase regulation by irradiation has never been evaluated in detail. In the present study, we investigated the effect of radiation on TA and its regulation in cancer cells. EXPERIMENTAL DESIGN: The effect of various radiation doses on TA in several malignant and nonmalignant cell lines was evaluated. All malignant cells exhibited similar telomerase response to radiation and its regulation was assessed at transcriptional and post-translational levels in K562 cells. Next step was the evaluation of the upstream signaling pathways leading to changes in TA using kinetics and specific inhibitors. RESULTS: Radiation up-regulated TA in dose-dependent manner only in cancer cells. Telomerase was activated by phosphorylation by Akt and by cytoplasmic-nuclear shift. Transcriptional processes were not involved in TA. This telomerase regulation is mediated by Ras/phosphatidylinositol 3-kinase/Akt pathway. The canonical membrane effectors of irradiation (epidermal growth factor receptor, insulin-like growth factor-I receptor, and Ca2+ influx) were not involved in this process. CONCLUSIONS: Radiation up-regulates telomerase activity specifically in cancer cells. This study adds to accumulating evidence pointing to post-translational level as important mode of telomerase regulation. Telomerase activation due to radiation may be detrimental in treatment of cancer. Data described in this study may add to future interventions aiming at inhibition of telomerase activation during irradiation.

Familial Mediterranean Fever Is Associated With Increased Mortality After Kidney Transplantation-A 19 Years' Single Center Experience.

BACKGROUND: Current data regarding the outcome of kidney transplantation in patients with familial Mediterranean fever (FMF) who reach end-stage renal disease (ESRD) due to reactive amyloidosis A (AA) are scarce and inconclusive. METHODS: The outcomes of 20 patients with FMF and biopsy-proven AA amyloidosis that were transplanted between 1995 and 2014 were compared with 82 control patients (32 with diabetes mellitus and 50 with nondiabetic kidney disease). Major outcome data included overall patient and graft survivals. RESULTS: During a mean overall follow-up of 116.6 ± 67.5 months 11 patients (55%) with FMF died versus 26 patients (31%) in the control group. Median time of death for patients with FMF was 61 months (range, 16-81) after transplantation. Estimated 5-year, 10-year, and actuarial 15-year overall patients survival rates were 73%, 45%, and 39%, respectively, for patients with FMF, versus 84%, 68% and 63%, respectively, for the control group (P = 0.028). FMF was associated with more than twofold increased risk for death after transplantation, and with a threefold increased risk for hospitalization because of infections during the first year. Infections and cardiovascular disease were the cause of death in the majority of patients with FMF. Overall graft survival was similar between the groups. Recurrence of AA amyloidosis was diagnosed in 2 patients during the first year after transplantation. CONCLUSIONS: FMF is associated with increased risk of mortality after kidney transplantation.

An intradialytic increase in serum interleukin-6 levels is associated with an increased mortality in hemodialysis patients.

BACKGROUND: The inflammatory marker interleukin-6 (IL-6) increases early in the inflammatory cascade. The aim of this study was to evaluate whether an increase in serum IL-6 levels during a hemodialysis (HD) session is associated with mortality. METHODS: 57 adult patients treated with HD for more than 1 month were prospectively studied over a 3-year follow-up period. Demographic and clinical data were collected and blood samples were drawn before and after a midweek HD session. Events of death and censoring were recorded. RESULTS: During the 3-year follow-up, 50.8% of the patients died. In univariate Cox regression analysis, an increase in IL-6 levels during HD was associated with an increased mortality (HR 1.41 per pg/ml; 95% CI 1.06 to 1.88; P = .017). In multivariate Cox models, the only independent predictors of all-cause mortality were: an increase in IL-6 levels during dialysis (HR 1.46 per pg/ml; 95% CI 1.08 to 1.98; P = .014), higher baseline C-reactive protein (CRP) levels and older age. When predictors of an increase in serum IL-6 levels during HD were introduced into the model, mortality was still significantly associated with IL-6 elevation during dialysis (HR 1.47 per pg/ml, 95% CI 1.01 to 2.14; P = .045). CONCLUSIONS: A rise in serum IL-6 levels during a single HD session is associated with a higher mortality among HD patients, independent of predialysis CRP or IL-6 levels. The results may imply the presence of an intradialytic inflammatory response that affects survival in HD patients.

Recurrent membranoproliferative glomerulonephritis type I after kidney transplantation: a 17-year single-center experience.

BACKGROUND: Most previously published studies of patients with membranoproliferative glomerulonephritis type I are small or have short follow-up period. We report the outcome of a fairly large cohort of patients followed up for nearly 10 years. METHODS: Retrospective cohort study. Graft survival, recurrence rate and risk factors for recurrence were analyzed for 43 patients transplanted between the years 1995 and 2012. RESULTS: At a mean overall follow-up of 118 ± 61 months (median, 127.8; range, 4.9-217), 12 patients lost their graft (28%). Death-censored actuarial 15-year graft survival rate was 56%. Membranoproliferative glomerulonephritis recurred in eight patients (19%) at a median time of 15.4 months (range, 4.4-70 months). Recurrence led to graft loss in seven patients (88%) within a median of 11.6 months (range, 1.3-54 months) from diagnosis. Median graft survival was 30.5 months for recurrence (range, 7-86). Actuarial 15-year graft survival was 71% for nonrecurrent. The risk for recurrence was higher for patients with human leukocyte antigen (HLA) B49 (odds ratio, 16.9; 95% confidence interval, 1.1-246; P=0.038) and HLA DR4 (odds ratio, 15.9; 95% confidence interval, 1.07-237; P=0.044) alleles. A trend toward increased risk was found with shorter duration of dialysis before transplantation. Four of 16 (25%) living-related versus none of the living-unrelated donors' recipients recurred. The HLA B49, acute tubular necrosis after transplantation, previous transplantations, and Arab origin were all associated with decreased graft and patient survival. CONCLUSION: Patients without recurrence in the first years should expect an excellent graft survival. Nonrelated living donors should be preferred. The HLA B49 and DR4 alleles may increase the risk for recurrence.

Effect of immunosuppressive drugs on DNA repair in human peripheral blood mononuclear cells.

INTRODUCTION: Cancer is a major cause of mortality among transplant recipients. Immunosuppressive treatment is a modifiable factor contributing to this phenomenon. Cyclosporine in kidney transplant recipients was associated with reduced UV-induced DNA repair by peripheral blood mononuclear cells (PBMC) and increased cancer rate. H(2)O(2) is a common cellular reactive oxygen species (ROS), which induces DNA damage followed by DNA repair. AIM: To investigate the effect of currently used immunosuppressive drugs on DNA repair. METHODS: H(2)O(2)-induced DNA repair by human PBMC was tested in vitro in the presence of the calcineurin inhibitors (CNI) cyclosporine and tacrolimus, mycophenolic acid (MPA), and the mammalian target of rapamycin (mTOR) inhibitors sirolimus and everolimus, at low to high non-toxic concentrations. The effect of combination therapy at maintenance levels was also tested. RESULTS: Cyclosporine and tacrolimus suppressed DNA repair throughout the tested dose range. In contrast, MPA, sirolimus and everolimus did so only at the high doses. Maintenance doses of a combination of tacrolimus and MPA, the most frequent treatment regimen, reduced DNA repair, while MPA with sirolimus or everolimus did not. CONCLUSION: In an attempt to reduce the risk of post-transplantation malignancy, treatment protocols may be modified by reducing CNI dose.