COVID-19 vaccinations: The unknowns, challenges, and hopes

The entire world has been suffering from the coronavirus disease 2019 (COVID‐19) pandemic since March 11, 2020. More than a year later, the COVID‐19 vaccination brought hope to control this viral pandemic. Here, we review the unknowns of the COVID‐19 vaccination, such as its longevity, asymptomatic spread, long‐term side effects, and its efficacy on immunocompromised patients. In addition, we discuss challenges associated with the COVID‐19 vaccination, such as the global access and distribution of vaccine doses, adherence to hygiene guidelines after vaccination, the emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) variants, and vaccine resistance. Despite all these challenges and the fact that the end of the COVID‐19 pandemic is still unclear, vaccines have brought great hope for the world, with several reports indicating a significant decline in the risk of COVID19‐related infection and hospitalizations.

1.

Vaccination plays a pivotal role in reducing the death toll of the COVID‐19 infection.

2.

The immunity provided by vaccines is still disputable leading to some challenges like the asymptomatic spread; therefore, staying strict to hygiene guidelines is necessary.

3.

Hence, COVID‐19 vaccines' related long‐term side effects are still unknown; cautions should be taken when injected to various individuals of the community.

4.

COVID‐19 vaccines' effectiveness are strongly related to their effect on emergent COVID‐19 variants, but until now approved vaccines can still show some protective effects against new variants.

Factors associated with hepatitis C antibody seroconversion after transplantation of kidneys from hepatitis C infected donors to hepatitis C naïve recipients

Background

We aimed to assess the probability and factors associated with the presence of hepatitis C virus (HCV) antibody among HCV seronegative kidney transplant recipients receiving HCV-infected (nucleic acid testing positive) donor kidneys.

Methods

This is a retrospective review examining HCV antibody seroconversion of all kidney transplant recipients receiving an organ from an HCV-infected donor between 1 March 2018 and 2 December 2019 at a high-volume kidney transplant center in the southeast United States.

Results

Of 97 patients receiving HCV-infected kidneys, the final cohort consisted of 85 recipients with 5 (5.9%) recipients noted to have HCV antibody seroconversion in the setting of HCV viremia. The HCV RNA level at closest time of antibody measurement was higher in the seroconverted patients versus the ones who never converted [median and (interquartile range): 1,091,500 (345,000–8,360,000) vs 71,500 (73–313,000), p = 0.02]. No other significant differences including type of immunosuppression were noted between the HCV antibody positive group and HCV antibody negative group. Donor donation after cardiac death status [Odds Ratio (OR) and 95% Confidence Interval (CI) was: 8.22 (1.14–59.14)], donor age [OR (95% CI) (+5 years) was: 3.19 (1.39–7.29)] and Kidney Donor Profile Index [OR (95% CI) (+1) was:1.07 (1.01–1.15)] showed a statistically significant association with HCV seroconversion.

Conclusions

HCV antibody should not be considered routine screening for presence of infection in previously HCV naïve kidney transplant recipients receiving kidneys from HCV-infected donors, as only a modest percentage have antibody despite active viremia. The assessment of HCV viral load should be routine in all transplant recipients receiving organs from public health service increased risk donors.

Oxygenated End-Hypothermic Machine Perfusion in Expanded Criteria Donor Kidney Transplant: A Randomized Clinical Trial

Importance

Continuous hypothermic machine perfusion during organ preservation has a beneficial effect on graft function and survival in kidney transplant when compared with static cold storage (SCS).

Objective

To compare the effect of short-term oxygenated hypothermic machine perfusion preservation (end-HMPo2) after SCS vs SCS alone on 1-year graft survival in expanded criteria donor kidneys from donors who are brain dead.

Design, Setting, and Participants

In a prospective, randomized, multicenter trial, kidneys from expanded criteria donors were randomized to either SCS alone or SCS followed by end-HMPo2 prior to implantation with a minimum machine perfusion time of 120 minutes. Kidneys were randomized between January 2015 and May 2018, and analysis began May 2019. Analysis was intention to treat.

Interventions

On randomization and before implantation, deceased donor kidneys were either kept on SCS or placed on HMPo2.

Main Outcome and Measures

Primary end point was 1-year graft survival, with delayed graft function, primary nonfunction, acute rejection, estimated glomerular filtration rate, and patient survival as secondary end points.

Results

Centers in 5 European countries randomized 305 kidneys (median [range] donor age, 64 [50-84] years), of which 262 kidneys (127 [48.5%] in the end-HMPo2 group vs 135 [51.5%] in the SCS group) were successfully transplanted. Median (range) cold ischemia time was 13.2 (5.1-28.7) hours in the end-HMPo2 group and 12.9 (4-29.2) hours in the SCS group; median (range) duration in the end-HMPo2 group was 4.7 (0.8-17.1) hours. One-year graft survival was 92.1% (n = 117) in the end-HMPo2 group vs 93.3% (n = 126) in the SCS group (95% CI, -7.5 to 5.1; P = .71). The secondary end point analysis showed no significant between-group differences for delayed graft function, primary nonfunction, estimated glomerular filtration rate, and acute rejection.

Conclusions and Relevance

Reconditioning of expanded criteria donor kidneys from donors who are brain dead using end-HMPo2 after SCS does not improve graft survival or function compared with SCS alone. This study is underpowered owing to the high overall graft survival rate, limiting interpretation.

Trial Registration

isrctn.org Identifier: ISRCTN63852508.

The incidence of cytomegalovirus infection after deceased-donor kidney transplantation from hepatitis-C antibody positive donors to hepatitis-C antibody negative recipients

BACKGROUND

Deceased-donor kidney transplantation (KT) from hepatitis C (HCV)-infected donors into HCV-uninfected recipients (HCV D+/R-) could become standard care in the near future. However, HCV viral replication by viral transmission might lead to a higher incidence of cytomegalovirus (CMV) infection in these recipients.

METHODS

A national-registry-based retrospective cohort study was conducted using the Scientific Registry of Transplant Recipients (SRTR) data set. We assessed the incidence of CMV infection in HCV antibody (Ab) negative recipients receiving kidneys from HCV Ab positive (HCVAb D+/R-) and negative (HCVAb D-/R-) donors. The risk of CMV infection was analyzed by Cox regression analysis in a propensity score (PS) matched-cohort of HCVAb D+/R- (n = 950) versus HCVAb D-/R- (n = 950). Sensitivity analysis was also conducted in the entire cohort (n = 181 082).

RESULTS

The mean age at baseline was 54 years, 75% were male, and 55% of the patients were African American in PS-matched cohort. Compared to the HCVAb D-/R - patients, recipients with HCVAb D+/R - showed identical probability for the incidence of CMV infection (Hazard Ratio (HR) = 1.00, 95% Confidence Interval (CI): 0.82-1.22). In the sensitivity analysis, compared to the HCVAb D-/R - patients, the HCVAb D+/R - group had a significantly lower risk of CMV infection in the unadjusted analysis (HR = 0.75, 95%CI: 0.65-0.85), while this risk difference disappeared after the adjusted analysis (HR = 0.99, 95%CI: 0.87-1.14).

CONCLUSION

The incidence of CMV infection was similar in recipients who received HCVAb D + and HCVAb D - KT. Further studies are needed to assess this association in KT from HCV nucleic acid positive donors.

Association between longer hospitalization and development of de novo donor specific antibodies in simultaneous liver-kidney transplant recipients

Background: De novo Donor Specific Antibodies (DSA) are considered as a risk factor for the kidney allograft outcomes in recipients after simultaneous liver-kidney transplantation (SLKT). We hypothesized that length of hospital stay (LOS) might be associated with de novo DSA development of due to the increased likelihood of receiving blood transfusions with reduced immunosuppressive regimens.Methods: This study is a single-center, retrospective cohort study consisting of 85 recipients who underwent SLKT from 2009 to 2018 in our hospital. We divided the patients into two groups according to LOS [long hospital stay (L) group (LOS >14 days) and short hospital stay (S) group (LOS ≤14 days)]. Propensity score (PS) has been created using logistic regression to predict LOS greater than median of 14 days. The association between the presence of de novo DSA and LOS was assessed by logistic regression models adjusted for PS.Results: The mean age at transplantation of the entire cohort was 55.5 ± 10.1 years. Sixty percent of the recipients were male and Caucasian. Median LOS in (L) group was three-fold longer than (S) group [L: median 30 days (IQR: 21-52), S: median 8.5 days (IQR: 7-11)]. Eight patients developed de novo DSA after SLKT (9.4%), all of them were in (L) group. Longer LOS was significantly associated with higher risk of development of de novo DSA in unadjusted (OR_{+ each 5 days}: 1.09, 95% CI:1.02-1.16) and PS adjusted (OR_{+ each 5 days}: 1.11, 95% CI:1.02-1.21) analysis.Conclusion: Longer hospitalization is significantly associated with the development of de novo DSA in SLKT.

P1758TOCILIZUMAB TREATMENT IN DSA POSITIVE ANTIBODY MEDIATED REJECTION AMONG KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Pretransplant or de novo donor specific antibodies (DSA) may lead to active or chronic active antibody mediated rejection (a and cABMR) as leading cause of graft loss after kidney transplantation. There is no treatment protocol approved for ABMR. Anti Il-6 tocilizumab (TCZ), inhibitor of DSA production, is a potential approach to stabilize kidney allograft function, however, evidence based results are not available.

In our retrospective case series analysis, we assessed the changes in DSA and eGFR during and at the end of treatment with TCZ.

Method

In our single center case series analysis, 10 kidney transplant patients with biopsy proven ABMR (aABMR 6, cABMR 4, age 43±10.5ys, 6 males, time since transplantation 18(2-119)months, 7 first transplant, serum creatinine 224±80 umol/L at baseline) were studied between January 2017 – June 2019. Total plasma exchange (PE) (5x) was followed by TCZ (8 mg/kg, 1x monthly for 6 months) in case of a and cABMR. Intravenous immunoglobulin (IVIG, 1gr/kg) was added in case of aABMR. Routine laboratory parameters and DSA were reported retrospectively.

Results

6 aABMR patients completed the treatment protocol. Class I DSA decreased significantly (MFI 4457(635-14084) vs. 877(595-5678); p=0.007), but Class II DSA remained the same during the treatment (MFI 4725 (586-17615) vs. 8097 (671-14636) p=NS). eGFR of aABMR patients and 1 cABMR patient were stabilized. 3 cABMR patients returned to dialysis. Reversible elevation of liver transaminases were detected in three patients. There was no any serious adverse event recorded.

Conclusion

The opportunely timed TCZ seems to be effective in reducing Class I DSA and stabilize graft function in patients with aABMR. Further studies are needed to prove the long-term efficacy and the exact role of TCZ in cABMR among kidney transplant patients.

P1666ASSOCIATION OF TACROLIMUS TROUGH LEVEL AND DAILY DOSE RATIO WITH OUTCOMES IN A PROSPECTIVE PREVALENT COHORT OF KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Tacrolimus is an integral part of the immunosuppressive regimen after solid organ transplantation. Due to its narrow therapeutic window, it requires frequent serum trough level (C0) monitoring and dose adjustment. Both over-and under treatment may have harmful effects regarding overall mortality and graft survival due to increased risk of cardiovascular diseases, malignancies, new onset diabetes and rejection. C0 and total daily dose ratio (CD) has recently been suggested as a potential predictor of worse graft outcome in the early period after transplantation, however, long term prospective studies are lacking. We hypothesized the association between lower CD ratio and increased risk of death with functioning graft (DWFG), graft loss (GL) and overall death (D) in our prospective cohort study.

Method

Our study included 386 prevalent kidney transplant recipients (205(53%) males, median and IQR age of 47.5 (13.2) years, eGFR 53.5 (22.5) ml/min/1.73m2, time since last transplant 51 (26-79) months) out of a total of 993 enrolled between 2006-2007. Sociodemographic, past medical history, clinical and laboratory data were collected and CD was recorded at baseline and 1 year after the enrollment. The associations between CD and CD2 ratios and above mentioned outcomes were examined using survival models..

Results

The median and IQR of CD was 2.1(1.4-3.2) at baseline and 2.0 (1.3-3.0) 1 year later (CD2). There was 46 (11.9%) DWFG, 79 (20.5%) GL and 68 (17.6%) D, respectively. After adjustment for important confounders (age, gender, eGFR, Charlson score, dialysis duration, donor age, rejection), neither CD (DWGL: HR 0.56(0.30-1.03) p=0.06; GL: HR 0.82(0.50-1.36) p=0.46; D: HR 0.79(0.48-1.32) p=0.38) nor CD2 (DWGL: HR 1.12(0.54-2.31) p=0.74; GL: HR 0.76(0.61-1.97) p=0.78; D: HR 1.19(0.64-2.20) p=0.59) found to be predictors of the outcomes.

Conclusion

CD ratio was not associated with increased risk of death with functioning graft, graft loss or overall death in our prevalent kidney transplant recipients.

P1774CONVERSION FROM TWICE-DAILY TACROLIMUS (TAC-IR) TO ONCE-DAILY EXTENDED RELEASE TACROLIMUS (LCPT) IN EVEROLIMUS TREATED STABLE KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Stable kidney transplant patients (KTX) treated according to TRANSFORM study protocol (TAC-IR + everolimus (EVR) + corticosteroid) were converted from twice daily TAC-IR to novel (MELT-dose) once-daily tacrolimus formulation (LCPT) on a 1:0.7 total daily dose (TDD) basis. Tolerability, safety, and trough level (Co) – TDD characteristics of the conversion (CV) was analyzed in a single center retrospective observational study.

Method

Between Sep. 2017 and Aug. 2018 38 KTX recipients were included. Pre- and post-CV TAC TDD, Co and TAC Co/D as well as EVR TDD and Co data were evaluated 4, 2 weeks before and 4 consecutive times after CV (94 (74-112 median IQR) post-transplant days). Pre- and post-CV eGFR, routine lab parameters and occurrence of adverse events were also investigated.

Results

In one patient 2 weeks after CV EVR was stopped due to infection, 37 KTX (males 22 (58%), age 54 (42-63) years) finished the entire observational period. According to CV protocol the median TDD of LCPT was lower than pre-CV TAC-IR at each visit: 4.5(3.5-7) mg/day pre-CV versus 3.5 (2.5-5), 3.6 (2.5-5), 3.5 (2.5-5) and 3.5 (2-5) (p<0.001) post-CV. Mean TAC Co decreased from pre-CV Co 7.8 (6.4-9.5) ng/ml to 6.7 (4.8, 8.6), 7.0 (5.2, 9.6), 6.5 (5.7, 8.4) and 7.2 (5.4, 8.7) (p<0.001). LCPT Co /TDD did not change: 1.6 (1.1-2.5) pre- and 2.1 (1.1- 2.9), 2.1 (1.1- 4.1), 1.6 (1.3- 3.5), 2.0 (1.4-4.1) (p = 0.18) post-CV. EVR Co /TDD (1.6 (1.3-2.1), 1.6 (1.3; 2.3), 1.6 (1.3-2.0), 1.6 (1.2-2.2)) remained similar to pre-CV: 1.6 (1.4- 2.4) (p = 0.65). There was no change in eGFR, hemoglobin levels and no drug related adverse event was observed during the study period.

Conclusion

Conversion from TAC-IR to LCPT in everolimus treated stable KTX recipients resulted in a significant post-CV decrease in TAC- Co, whilst Co/TDD remained unchanged. The conversion was safe and had no effect on EVR Co and TDD. Further investigations are needed to define optimal TAC-IR to LCPT conversion dose rate.

Transplantation of kidneys from hepatitis C-infected donors to hepatitis C-negative recipients: Single center experience

Our aim was to evaluate the safety of transplanting kidneys from HCV-infected donors in HCV-uninfected recipients. Data collected from 53 recipients in a single center, observational study included donor and recipient characteristics, liver and kidney graft function, new infections and de novo donor-specific antibodies and renal histology. Treatment with a direct-acting antiviral regimen was initiated when HCV RNA was detected. The mean ± SD age of recipients was 53 ± 11 years, 34% were female, 19% and 79% of recipients were white and African American, respectively. The median and interquartile range (IQR) time between transplant and treatment initiation was 76 (IQR: 68-88) days. All 53 recipients became viremic (genotype: 1a [N = 34], 1b [N = 1], 2 [N = 3], and 3 [N = 15]). The majority (81%) of recipients did not experience clinically significant increases (>3 times higher than upper limit of the normal value) in aminotransferase levels and their HCV RNA levels were in the 5 to 6 log range. One patient developed fibrosing cholestatic hepatitis with complete resolution. All recipients completed antiviral treatment and 100% were HCV RNA-negative and achieved 12-week sustained virologic response. The estimated GFRs at end of treatment and 12-week posttreatment were 67 ± 21 mL/min/1.73 m² and 67 ± 17 mL/min/1.73 m² , respectively. Four recipients developed acute rejection. Kidney transplantation from HCV-infected donors to HCV-negative recipients should be considered in all eligible patients.

History of posttraumatic stress disorder and outcomes after kidney transplantation

A history of posttraumatic stress disorder (PTSD), if uncontrolled, represents a contraindication for kidney transplantation. However, no previous large study has assessed the association between pretransplant history of PTSD and posttransplantation outcomes. We examined 4479 US veterans who had undergone transplantation. The diagnosis of history of PTSD was based on a validated algorithm. Measured covariates were used to create a matched cohort (n = 560). Associations between pretransplant PTSD and death with functioning graft, all-cause death, and graft loss were examined in survival models. Posttransplant medication nonadherence was assessed using proportion of days covered (PDC). From among 4479 veterans, 282 (6.3%) had a history of PTSD. The mean age ± standard deviation (SD) of the cohort at baseline was 61 ± 11 years, 91% were male, and 66% and 28% of patients were white and African American, respectively. Compared to patients without a history of PTSD, patients with a history of PTSD had a similar risk of death with a functioning graft (subhazard ratio [SHR] 0.97, 95% confidence interval [CI] 0.61-1.54), all-cause death (1.05, 0.69-1.58), and graft loss (1.09, 0.53-2.26). Moreover, there was no difference in immunosuppressive drug PDC in patients with and without a history of PTSD (PDC: 98 ± 4% vs 99 ± 3%, P = .733 for tacrolimus; PDC: 99 ± 4% vs 98 ± 7%, P = .369 for mycophenolic acid). A history of PTSD in US veterans with end-stage renal disease should not on its own preclude a veteran from being considered for transplantation.

Association between malnutrition-inflammation score and risk of subsequent self-reported bone fractures in prevalent kidney transplant recipients

Chronic inflammation and protein energy wasting (PEW) syndrome are common in kidney transplant recipients (KTR). The presence of inflammation and PEW syndrome can directly affect bone resorption and bone formation, leading to bone loss and fractures. We showed PEW is independently associated with new clinically detected bone fractures in prevalent KTR.

INTRODUCTION

Kidney transplant recipients (KTR) have a 4-fold higher risk of fracture compared to the general population. Chronic inflammation and PEW syndrome are common in KTR and are associated with poor outcomes. We hypothesized that the Malnutrition-Inflammation Score (MIS), a validated measure of PEW, is associated with higher risk of bone fractures in KTR.

METHODS

This prospective cohort study included 839 prevalent KTR from a Central European academic center. MIS, a semiquantitative instrument of PEW, was calculated at the study entry. Self-reported history of fractures was recorded during the 2-year follow-up period. The association between MIS and bone fractures was examined in logistic regression analyses with adjustment for age, gender, eGFR, smoking habits, history of pre-transplant bone fractures, and acute rejection.

RESULTS

Mean age was 51 ± 13 years, and 56% of patients were males with median (interquartile range) transplant vintage 69 (38-112) months, estimated glomerular filtration rate 55 ± 21 ml/min/1.73 m², and calculated MIS 3 (2-4) at enrollment. Fifty-five (7%) patients experienced self-reported bone fractures during the 2-year follow-up period. Higher MIS score showed linear association with increased risk of fracture. Each one-point higher MIS was associated with 23% higher risk of bone fractures (odds ratio (OR) and 95% CI 1.23, 1.12-1.34), which remained significant after multivariable adjustments (OR 1.17, 95% CI 1.06-1.29).

CONCLUSION

The MIS is independently associated with new clinically detected bone fractures in prevalent KTR.

Association Between Serum Prealbumin Level and Outcomes in Prevalent Kidney Transplant Recipients

OBJECTIVE(S)

Prealbumin, a transport protein mostly synthesized in the liver, is a marker of nutrition. Although decreased prealbumin levels are associated with increased mortality in end-stage kidney disease patients, its association with mortality in kidney transplant recipients remains unknown. We evaluated the association between prealbumin levels and outcomes in kidney transplant recipients.

DESIGN

This was a prospective prevalent cohort study. This study included 991 kidney transplant recipients enrolled from December 31, 2006, to December 31, 2007, and followed over a 6-year period. Sociodemographic, past medical history, clinical, and laboratory data were collected at the study entry. Associations between prealbumin levels and death with functioning graft, all-cause mortality, and graft loss were examined using survival models.

RESULTS

Serum prealbumin levels showed significant negative correlation with estimated glomerular filtration rate (R = -0.28; P < .001) and high-sensitive C-reactive protein (R = -0.24; P < .001). Each 5 mg/dL lower serum prealbumin level was associated with 20% higher risk of death with functioning graft (subdistribution hazard ratio [95% confidence interval]: 1.20 [1.08-1.35]; P = .001), which persisted after multivariable adjustments (subdistribution hazard ratio [95% confidence interval]: 1.13 [1.00-1.28]; P = .039). Qualitatively similar trend was observed in all-cause mortality; however, there was no association between prealbumin levels and graft loss.

CONCLUSION(S)

Lower serum prealbumin level is associated with increased risk of death with functioning graft in prevalent kidney transplant recipients.

The impact of currently recommended antihypertensive therapy on depression and other psychometric parameters: preliminary communication

AIMS

Current evidence on the psychological effects of antihypertensive medications is controversial. The aim of this study was to evaluate the effect of current antihypertensive medication on different psychometric parameters and on serum brain-derived neurotrophic factor (BDNF) level.

METHODS

Psychometric, haemodynamic, arterial stiffness and laboratory parameters were evaluated before and 3 months after the initiation of antihypertensive medication in untreated hypertensive patients (HT, n=31), and once in healthy controls (CONT, n=22). Subjects completed the following psychometric tests: Beck Depression Inventory (BDI), Hamilton Anxiety Scale (HAM-A), Symptom Checklist 90 Revised (SCL-90), Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire, Big Five Inventory, Pain Vigilance and Awareness Questionnaire and Berkeley Expressivity Questionnaire. Amlodipine and/or perindopril compounds were preferred medications. Serum BDNF was measured with ELISA.

RESULTS

Brachial systolic blood pressure, as well as pulse wave velocity were significantly improved in the HT group over the 3-month follow-up (153.3±15.9 mmHg vs. 129.5±10.0 mmHg and 8.2±1.4 m/s vs 7.5±1.6 m/s, respectively). Similarly, we found improvements in BDI (0.73 points) and in several Scl-90 subscales. Serum BDNF was not different between CONT and HT and did not change for therapy.

CONCLUSIONS

Our results indicate that initiation of currently recommended antihypertensive medications in newly diagnosed patients may have a significant impact on psychological well-being of patients and could influence quality of life as well.

Reference Values of Pulse Wave Velocity in Healthy Children and Teenagers

Carotid-femoral pulse wave velocity is an established method for characterizing aortic stiffness, an individual predictor of cardiovascular mortality in adults. Normal pulse wave velocity values for the pediatric population derived from a large data collection have yet to be available. The aim of this study was to create a reference database and to characterize the factors determining pulse wave velocity in children and teenagers. Carotid-femoral pulse wave velocity was measured by applanation tonometry. Reference tables from pulse wave velocities obtained in 1008 healthy subjects (aged between 6 and 20 years; 495 males) were generated using a maximum-likelihood curve-fitting technique for calculating SD scores in accordance with the skewed distribution of the raw data. Effects of sex, age, height, weight, blood pressure, and heart rate on pulse wave velocity were assessed. Sex-specific reference tables and curves for age and height are presented. Pulse wave velocity correlated positively ( P <0.001) with age, height, weight, and blood pressure while correlating negatively with heart rate. After multiple regression analysis, age, height, and blood pressure remained major predictors of pulse wave velocity. This study, involving >1000 children, is the first to provide reference values for pulse wave velocity in children and teenagers, thereby constituting a suitable tool for longitudinal clinical studies assessing subgroups of children who are at long-term risk of cardiovascular disease.