The detrimental effect of donor-specific antibodies is irrespective of its level in highly-immunized living donor kidney transplant recipients: A case-control series

Background

The impact of donor-specific antibodies (DSA) in (highly-) immunized living donor kidney transplant recipients is reported differentially in various patient cohorts.

Methods

We have performed a retrospective analysis of all consecutive HLA-incompatible living donor kidney transplant recipients in our center between 2010-2019. Recipients who underwent plasmafiltration for a positive CDC-crossmatch were excluded. For each DSA+ recipient (DSA+), one immunized recipient without DSA (pPRA+) and two non-immunized recipients (pPRA-) were included. Patient and graft survival were analyzed and a subgroup analysis of DSA+ recipients was performed.

Results

For 63 DSA+ recipients, 63 PRA+ and 126 PRA- recipients were included. 26 (41%) had class I, 24 (38%) class II and 13 (21%) combined HLA class I and II DSA. Death-censored graft survival was inferior in DSA+ recipients compared to pPRA+ (HR 2.38 [95% CI 1.00-5.70]) as well as to pPRA- (HR 3.91 [1.86-8.22]). In multivariate analysis, DSA remained of negative influence on death-censored graft survival. Flowcytometric crossmatch, MFI value, HLA class and origin of DSA were not of significant impact.

Conclusion

In our cohort of (highly-) immunized recipients, pretransplant DSA led to inferior death-censored graft survival. There were no "safe" DSA characteristics since only DSA per se impacted death-censored graft survival.

Fasting before living-kidney donation: effect on donor well-being and postoperative recovery: study protocol of a multicenter randomized controlled trial

BACKGROUND

One of the main effectors on the quality of life of living-kidney donors is postoperative fatigue. Caloric restriction (CR) and short-term fasting (STF) are associated with improved fitness and increased resistance to acute stress. CR/STF increases the expression of cytoprotective genes, increases immunomodulation via increased anti-inflammatory cytokine production, and decreases the expression of pro-inflammatory markers. As such, nutritional preconditioning by CR or STF represents a non-invasive and cost-effective method that could mitigate the effects of acute surgery-induced stress and postoperative fatigue. To investigate whether preoperative STF contributes to a reduction in fatigue after living-kidney donation, a randomized clinical trial is indicated.

METHODS

We aim to determine whether 2.5 days of fasting reduces postoperative fatigue score in subjects undergoing living-kidney donation. In this randomized study, the intervention group will follow a preoperative fasting regime for 2.5 days with a low-dose laxative, while the control group will receive standard care. The main study endpoint is postoperative fatigue, 4 weeks after living-kidney donation. Secondary endpoints include the effect of preoperative fasting on postoperative hospital admission time, the feasibility of STF, and the postoperative recovery of donor and recipient kidney function. This study will provide us with knowledge of the feasibility of STF and confirm its effect on postoperative recovery.

DISCUSSION

Our study will provide clinically relevant information on the merits of caloric restriction for living-kidney donors and recipients. We expect to reduce the postoperative fatigue in living-kidney donors and improve the postoperative recovery of living-kidney recipients. It will provide evidence on the clinical merits and potential caveats of preoperative dietary interventions.

TRIAL REGISTRATION

Netherlands Trial Register NL9262 . EudraCT 2020-005445-16 . MEC Erasmus MC MEC-2020-0778. CCMO NL74623.078.21.

Disrupted regulation of serpinB9 in circulating T cells is associated with an increased risk for post-transplant skin cancer

Cutaneous squamous cell carcinoma (cSCC) is a serious complication after organ transplantation and patients benefit from an early risk assessment. We hypothesized that functional differences in circulating T cells may represent risk factors for post‐transplant cSCC development. Here, we analysed genome‐wide DNA methylation of circulating T cells of kidney transplant recipients before the clinical onset of cSCC, to identify differences associated with post‐transplant cSCC development. This analysis identified higher DNA methylation of SERPINB9, which is an intracellular inhibitor of granzyme B, a protein that induces apoptosis in target cells. High DNA methylation of SERPINB9 in circulating T cells was confirmed in a second patient cohort during recurrent cSCC, indicating that high SERPINB9 methylation represents a persistent risk factor for cSCC development. At the functional level, the inverse correlation between DNA methylation and messenger RNA expression present in non‐cSCC patients was absent in the cSCC patients. Also, a significant difference in serpinB9 protein expression between cSCC patients and non‐cSCC patients was observed. It was concluded that disturbed regulation of serpinB9 in circulating T cells represents a novel risk factor for post‐transplant cSCC in kidney transplant recipients.

Conversion from tacrolimus to everolimus with complete and early glucocorticoid withdrawal after kidney transplantation: a randomised trial

BACKGROUND

While conversion from cyclosporine to everolimus is well documented, conversion from tacrolimus has been poorly studied. In this randomised, controlled trial the safety and tolerability of switching from tacrolimus to everolimus with glucocorticoid withdrawal after living-donor kidney transplantation was studied.

METHODS

A total of 194 patients were planned to be randomised 1:1 to either continue tacrolimus or to convert to everolimus at month 3 after transplantation. At randomisation, all patients received tacrolimus, mycophenolate mofetil and prednisolone. Everolimus was started in a dose of 1.5 mg twice daily, aiming for predose concentrations of 4-7 ng/ml. Prednisolone was gradually withdrawn in both groups.

RESULTS

The trial was stopped prematurely after the inclusion of 60 patients. The interim analysis showed an unacceptably high rejection rate in the everolimus group as compared with the control group: 30.0% vs. 6.7% (95% CI: 0.047-0.420; p = 0.045). An additional 8 patients stopped everolimus because of toxicity. At the end of follow-up (month 12) only 12 (40%) patients assigned to everolimus were still on the study drug.

CONCLUSIONS

Conversion from tacrolimus to everolimusbased immunosuppression with withdrawal of prednisolone three months after kidney transplantation results in an unacceptably high risk of acute rejection and causes considerable toxicity. Based on our findings, such a switch strategy cannot be recommended.

A Randomized Controlled Trial Comparing the Efficacy of Cyp3a5 Genotype-Based With Body-Weight-Based Tacrolimus Dosing After Living Donor Kidney Transplantation

Patients expressing the cytochrome P450 (CYP) 3A5 gene require a higher tacrolimus dose to achieve therapeutic exposure compared with nonexpressers. This randomized-controlled study investigated whether adaptation of the tacrolimus starting dose according to CYP3A5 genotype increases the proportion of kidney transplant recipients being within the target tacrolimus predose concentration range (10-15 ng/mL) at first steady-state. Two hundred forty living-donor, renal transplant recipients were assigned to either receive a standard, body-weight-based or a CYP3A5 genotype-based tacrolimus starting dose. At day 3, no difference in the proportion of patients having a tacrolimus exposure within the target range was observed between the standard-dose and genotype-based groups: 37.4% versus 35.6%, respectively; p = 0.79. The proportion of patients with a subtherapeutic (i.e. <10 ng/mL) or a supratherapeutic (i.e. >15 ng/mL) Tac predose concentration in the two groups was also not significantly different. The incidence of acute rejection was comparable between both groups (p = 0.82). Pharmacogenetic adaptation of the tacrolimus starting dose does not increase the number of patients having therapeutic tacrolimus exposure early after transplantation and does not lead to improved clinical outcome in a low immunological risk population.

Determination of the Bioavailability of [14C]-Hexaminolevulinate Using Accelerator Mass Spectrometry After Intravesical Administration to Human Volunteers

Hexaminolevulinate (HAL) is a diagnostic agent that allows the visualization of tumor tissue in the bladder by fluorescence cystoscopy. It is administered intravesically via a catheter for 1 hour, followed by blue light bladder inspection to induce selective red tumor fluorescence. Hexaminolevulinate should ideally be confined to the bladder only, but it is likely that some absorption occurs during administration, and therefore the systemic bioavailability is of interest. The bioavailability of HAL was determined by intravesical and intravenous administration of [14C]-HAL hydrochloride to 8 human volunteers. To reduce the radiation dose as low as possible, the ultrasensitive analytical technique of accelerator mass spectrometry was used to measure [14C]-HAL. The bioavailability of [14C]-HAL after intravesical and intravenous administration was determined from the respective area under the curve based on total radioactivity and was determined to be 7% (range, 5%-10%; 90% confidence interval). The systemic absorption of [14C]-HAL after intravesical administration is low and supports previous clinical experience with HAL showing no systemic side effects.

Randomised clinical trial: anti-viral activity of ANA773, an oral inducer of endogenous interferons acting via TLR7, in chronic HCV

BACKGROUND

The ANA773 is an oral prodrug of a small-molecule toll-like receptor (TLR)7 agonist. Preclinical and healthy volunteer clinical studies with ANA773 have demonstrated induction of endogenous interferon-α (IFN-α) of multiple subtypes, which supports the potential utility in the treatment of chronic hepatitis C virus (HCV) infection.

AIM

To examine safety, tolerability, pharmacodynamics, pharmacokinetics and anti-viral activity of ANA773.

METHODS

The ANA773 was investigated in a double-blind, placebo-controlled study in 34 patients chronically infected with HCV of any genotype. Patients were treatment-naïve or had relapsed following previous interferon-based treatment. This dose escalation study was composed of four dose groups (800, 1200, 1600 and 2000mg). In each group, six to eight patients received ANA773 and two received placebo. Patients were dosed with ANA773 every-other-day for either 28 days (800, 1200 or 1600mg) or 10days (2000mg).

RESULTS

Mild to moderate adverse events were reported, with an increase in frequency and intensity with increasing dose. No serious AEs were reported and there were no early discontinuations. There were dose-related increases in various markers of IFN-α response. The mean maximum change in serum HCV RNA level from baseline was -0.34, -0.29, -0.40, -0.97 and -1.26log(10) in the placebo, 800, 1200, 1600 and 2000mg cohorts, respectively. At the 2000mg dose, ANA773 significantly (P=0.037) reduced serum HCV RNA levels (range: 0.14 to -3.10log(10) ).

CONCLUSION

The ANA773 was generally well tolerated and resulted in a dose-related IFN-dependent response leading to a significant decrease in serum HCV RNA levels in the 2000mg dose group.

Successful expansion of the living donor pool by alternative living donation programs

Between January 2000 and December 2007, 786 potential recipients and 1059 potential donors attended our pretransplant unit with the request for a living-donor renal transplant procedure. The recipients brought one potential donor in 77.2% and two or more donors in 22.8% of cases. In the regular living donor program, a compatible donor was found for 467 recipients. Without considering alternative donation, 579 donors would have been refused. Alternative living donation programs led to 114 compatible combinations: kidney-exchange program (35), ABO-incompatible donation (25), anonymous donation (37) and domino-paired anonymous donation (17). Together, the 114 alternative program donations and the 467 regular living donations led to 581 living donor transplantations (24.4% increase). Eventually for 54.9% (581/1059) of our donors, a compatible combination was found. Donor-recipient incompatibility comprised 19.4% (89/458) in the final refused population, which is 8.8% of the potential donor-recipient couples. Without considering alternative donation, 30.1% (174/579) of the refused donors would have been refused on incompatibility and 6.4% (37/579) because they were anonymous. This is 20% of the potential donor population (211/1059). The implementation of alternative living donation programs led to a significant increase in the number of transplantations, while transplantations via the direct donation program steadily increased.

Donor-Reactive Cytokine Production After HLA-Identical Living Related Kidney Transplantation: A Protein-Array Analysis

In the present pilot study, we investigated which proteins are produced after donor stimulation of peripheral blood mononuclear cells from recipients of HLA-identical living related kidney transplant. We used a protein-array analysis to determine cytokines, chemokines, and growth factors in supernatant from donor-stimulated mixed lymphocyte reaction cultures. Autologous cultures were considered to be negative controls. In 38 out of 42 proteins (90%), the donor response was higher compared with the autologous response. Therefore, we concluded that even after HLA-identical living related kidney transplantation we could measure a donor-reactive response, which we assumed was directed toward minor histocompatibility or non-HLA antigens.

Reduction of immunosuppressive load in renal transplant recipients with a low donor-specific cytotoxic T-lymphocyte precursor frequency is safe

BACKGROUND

Tapering of immunosuppressive medication is indicated to prevent long-term side effects. Recently, we have shown that renal transplant recipients can safely be converted from calcineurin inhibitors to MMF or AZA when their donor-specific cytotoxic T-lymphocyte precursor frequencies (CTLpf) are below 10/10(6) PBMC. We wondered whether a low CTLpf also had predictive value when immunosuppressive medication was reduced in patients only on MMF or AZA and steroid medication.

METHODS

Renal transplant recipients with stable renal function at least 2 years after transplantation and with low (<10/10(6) PBMC) CTLpf were included. Their MMF or AZA dose was reduced to 75% and to 50% of the original dose at 4 months and 8 months after inclusion. Endpoint of the study was 12 months after inclusion or developing acute rejection.

RESULTS

Forty-five patients have reached the 1-year follow up endpoint. Their median time after transplantation was 4.2 years (range 2.0-15.5 years). Acute rejection was seen in one patient only (who had discontinued all his medication).

CONCLUSION

In patients with low CTLpf long after kidney transplantation, a 50% reduction of immunosuppression is safe and further decreasing their immunosuppressive load is the obvious next step.

Granzyme B ELISPOT Assay Determines the Cytotoxic T Lymphocyte Precursor Frequency After HLA-Identical Living-Related Kidney Transplantation

A major goal in organ transplantation is to define the optimal immunosuppressive dose. Recently, we demonstrated that the frequency of cytotoxic T lymphocytes (CTLpf) identifies patients in whom the immunosuppressive load can be safely reduced. However, in peripheral blood mononuclear cells (PBMC) from HLA-identical living-related kidney transplant patients, no donor-specific CTLpf can be measured. The determination of the functional activity of cytotoxic T lymphocytes (CTLs) could be an alternative method for the CTLpf. Granzyme B (GrB) is present in the granules of CTLs and is involved in the direct lethal hit of donor target cells. Therefore, we wondered whether the GrB ELISPOT assay is an alternative method to determine the activity of CTLs after HLA-identical living-related kidney transplantation. We measured the number of GrB producing cells (pc) against donor PBMC and third-party PBMC in PBMC from HLA-identical patients who were reduced in their immunosuppression from 100% to 50% azathioprine with 5 to 10 mg/day prednisone. We found low numbers of GrB pc before reduction of immunosuppression, as only 20% of the patients' PBMC responded to donor cells, whereas 57% of the patients' PBMC responded to donor cells after reduction of immunosuppression. After third-party stimulation, the number of GrB pc increased after tapering the immunosuppressive load (P = .03). Our results demonstrate that the GrB ELISPOT assay might be used as an alternative for the CTLpf after HLA-identical living-related kidney transplantation.

Cardiac and metabolic effects in patients who present with a multinodular goitre

Twenty-six consecutive patients who presented with clinically euthyroid multinodular goitre were studied for an overnight fasting serum lipid profile and 24 h Holter monitoring. Mean serum TSH was 0.6 +/- 0.4 vs 2.4 +/- 1.3 mU/l (p < 0.0001) and mean TT3 2.4 +/- 0.4 vs 2.0 +/- 0.5 nmol/l (p = 0.009) in patients vs controls (n = 15) while mean FT4 was not different from controls. Total serum HDL, LDL cholesterol and triglycerides were lower in patients but creatinine, ferritin and SHBG levels did not differ between patients and controls. The 24-hour ambulatory continuous ECG recordings did not demonstrate significant differences in mean, minimal and maximal heart rate between the study and the control group. Nocturnal heart rate, measured between 23.00 and 06.00 hours, also showed no differences between the two groups. Atrial fibrillation was absent in both the study and the control group. Premature atrial and ventricular complexes occurred equally frequently in both groups. Comparison of patients with a serum TSH below 0.4 mU/l (n = 11) and patients with a TSH above 0.4 mU/l revealed no differences. In conclusion, in consecutive patients who present with multinodular goitre, effects were found on the lipid profile, but not on the heart. It is argued that in this type of patients, cardiac effects depend on the degree of subclinical hyperthyroidism.

Acute epiglottitis as a cause of airway obstruction in an adult patient

Epiglottitis in adults is a dangerous infectious disease with a rising incidence and potential fatal complications as illustrated in this case report. Like in children, skilled and aggressive airway protection with appropriate antibiotic therapy have been effective in reducing mortality.

Heparin use in continuous renal replacement procedures: the struggle between filter coagulation and patient hemorrhage

Heparin is the most widely used anticoagulant in continuous renal replacement procedures but little is known about the balance between filter coagulation and patient hemorrhage during treatment. Filter survival and hemorrhagic complications during 240 filter periods in 78 critically ill patients, treated with continuous arteriovenous hemofiltration and hemodiafiltration, were studied for this article. The crude incidence of filter coagulation was 17.7 +/- 2.5 (mean +/- SE) per 1000 h at an activated partial thromboplastin time (APTT) of 15 to 35 s, as determined in systemic blood samples. The incidence of filter coagulation gradually decreased to 9.0 +/- 2.7 per 1000 h at an APTT of 45 to 55 s (P = 0.031). The crude incidence of patient hemorrhage was 2.9 +/- 1.0 per 1000 h at an APTT of 15 to 35 s and increased almost threefold to 7.4 +/- 2.4 per 1000 h when the APTT was 45 to 55 s (P = 0.009). There was no difference in filter survival between treatment with hemofiltration only and hemodiafiltration. Mean survival of acrylonitrile filters (33.8 +/- 4.3) was significantly lower compared with the survival of polyamide filters (104.1 +/- 14.4 h, P = 0.003). After adjustment for the type of the filter, mean arterial blood pressure, and platelet count, the risk for filter coagulation decreased 25% (relative risk, 0.77; 95% confidence interval [CI], 0.62 to 0.96) for every 10-s increase in APTT. At the same time, the risk for patient hemorrhage increased 50% (relative risk, 1.57; 95% CI, 1.43 to 1.72). The occurrence of filter coagulation or hemorrhages were not correlated with the administered dose of heparin. Concurrent use of coumarin derivatives had a positive effect on filter survival, without increasing the overall incidence of hemorrhages. It was concluded that the systemic APTT is a good predictor of the risk for filter coagulation and patient hemorrhage. Safety and efficacy of heparin therapy seems optimal at an APTT between 35 and 45 s.

Modeling the contractility of urinary bladder smooth muscle using isometric contractions

In the course of developing a clinical contractility index, isometric contractions of pig urinary bladder smooth muscle were analyzed in terms of phase plots (a plot of the rate of change of a variable, in this case force, as a function of the variable itself). The straight line describing the major part of the phase plots is characterized by the two parameters Fiso (the horizontal intercept) and c (the slope) of the line. It was found that changes in the geometry of the tissue sample and changes in extracellular calcium grossly influence Fiso, but not c, whereas changes in prestimulus rest time influence c, but not Fiso. It is concluded that Fiso is related to the number of available contractile units, and c is related to the limiting rate constant in the excitation-contraction coupling, which is probably determined by the release of intracellular calcium. The existence of the calcium paradox and the interpretation of the concept of facilitation or potentiation in this type of smooth muscle are discussed.

Influence of temperature and stimulus interval variations on the propagation of contractions in the pig ureter

The influences of ureter temperature and time interval between stimulations on the velocity of propagation of contractions in the pig ureter were studied in vitro. The propagation velocity was calculated from electromyogram signals measured at regular distances along the ureter. It was found that a temperature decrease of 3 degrees C causes a velocity decrease of nearly 5 mm/s. The influence of the interstimulus interval is much smaller: a reduction from 300 to 10 s causes a 10% drop in propagation velocity. Both phenomena can be understood from changes in the strength-duration curve describing the excitability of the tissue and clarify the discrepancies between propagation velocity measurements in vitro and in vivo.