FOXP3 full length splice variant is associated with kidney allograft tolerance

Background

Progressive decline of allograft function leads to premature graft loss. Forkhead box P3 (FOXP3), a characteristic gene of T-regulatory cells, is known to be essential for auto-antigen tolerance. We assessed the hypothesis that low FOXP3 mRNA splice variant levels in peripheral blood cells early after transplantation are associated with progressive allograft injury.

Methods

Blood samples were prospectively collected from 333 incident kidney transplant recipients on the first and 29th postoperative day. We used quantitative polymerase chain reaction to determine transcripts of 3 isotypes of FOXP3 splice variants, including pre-mature FOXP3 and full length FOXP3 (FOXP3fl). We investigated the association between FOXP3 splice variant levels and the declines in estimated glomerular filtration rate (eGFR) of more than 5ml/min/1.73m2 within the first-year post-transplant using logistic regression.

Results

We observed lower FOXP3fl levels in recipients with declining eGFR (N = 132) than in recipients with stable eGFR (N = 201), (logarithmic value -4.13 [IQR -4.50 to -3.84] vs -4.00 [4.32 to -3.74], p=0.02). In ad hoc analysis pre-transplant FOXP3fl levels were similar in both groups. The association between FOXP3fl and declining eGFR was confirmed by multivariable analysis adjusted for potential confounding factors (Odds Ratio 0.51, 95% confidence interval 0.28 to 0.91: p=0.02). When stratifying FOXP3fl levels into quartiles, recipients with lower day1 FOXP3fl had the highest rate of declining eGFR (p=0.04).

Conclusion

Low FOXP3fl splice variant levels at the first postoperative day in kidney transplant recipients were associated with severe decline of eGFR, a well-known surrogate for hard endpoints.

Lower levels of FOXP3 are associated with prolonged inflammatory responses in kidney transplant recipients

Background

Immunosuppressive treatment of kidney transplant recipients is mainly aimed at pro-inflammatory T effector cells, yet they also target the immunosuppressive T regulatory cells. Here, we test the hypothesis that low levels of the master gene regulator of T regulatory cells, forkhead box P3 (FOXP3) splice variants, are associated with prolonged inflammatory responses to stimuli.

Methods

From blood samples obtained the first - and 29th day post-transplant, we extracted peripheral blood mononuclear cells and measured mRNA levels of Total FOXP3, pre-mature RNA FOXP3 (pre-mRNA FOXP3), full length FOXP3 (FOXP3fl) and, FOXP3 splice variant excluding exon two (FOXP3d2). We defined the primary outcome as the number of days in which C reactive protein (CRP) was above 50 mg/L. CRP levels were gathered in two periods, the first from the second to 29 days post-transplant, and the second from 30 to 57 days post-transplant. The association was tested using adjusted negative binomial regression.

Results

From 507 included kidney transplant recipients, 382 recipients had at least one CRP measurement >50 mg/L in the first period, median duration of elevated CRP was 4 days [interquartile range (IQR) 2 to 6]. In the second period, 69 recipients had at least one CRP measurement >50 mg/L, median duration of elevated CRP was 3 days [IQR 2 to 5]. In the first period, we found a significant association between lower levels of Total FOXP3 and prolonged duration of CRP elevation, incidence rate ratio 0.61 (95% confidence interval 0.46-0.80), p<0.01.

Conclusion

Lower levels of total FOXP3 mRNA levels in peripheral blood of kidney transplant recipients are associated with prolonged duration of inflammatory responses regardless of the underlying stimuli.

Kidney function, future health costs, and quality-adjusted life-years in kidney transplant recipients transplanted during the SARS-Cov-2 lockdown in Denmark - An observational study

Background

It is unknown whether lockdown due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may affect both clinical outcome in kidney transplant recipients and health care economics in Denmark.

Methods

We compared kidney transplant data at a tertiary university hospital before and during the lockdown period from March 13, 2020 until March 31, 2021, as well as kidney transplant data from Scandiatransplant for entire Denmark. Outcome variables included fall of plasma creatinine during the first postoperative day, and graft function three months posttransplant. We calculated the quality-adjusted life-years (QALYs) and costs which were caused by the lockdown recommendations.

Findings

The portion of living donation kidney transplantation was largely reduced during the lockdown period compared to before the lockdown: AB0-incompatible living donation declined from 14% to 7% (P < 0.01), and AB0-compatible living donation declined from 34% to 20% (p < 0.01).

In entire Denmark during the lockdown period 78 living donor kidney transplants out of 268 kidney transplants (29%) were performed, whereas there were 878 living donor kidney transplants out of 2218 kidney transplants (39%) before the lockdown (P = 0.01).

The observed reduction of living donor kidney transplants and consecutive reduction of graft survival will cause a loss of 5.04 QALYs.

The additional costs in kidney transplant recipients who received a kidney transplant during the lockdown period will be 277,298 EUR.

Interpretation

SARS-CoV-2 lockdown period largely reduced living donation kidney transplants which will lead to reduced QALY as well as higher costs in kidney transplant recipients.

Ascending Aortic Diameter after Dissection Does Not Reflect Size before Dissection

Introduction

Current guidelines for prophylactic resection of ascending aortic aneurysms are based on post-dissection aortic diameter. However, this may not reflect the diameter prior to dissection.

Report

Pre- and post-dissection aortic diameters were compared in 34 patients with available computerised tomography scans. The median time interval between these scans was 536 days (interquartile range 354 – 1237).

Discussion

There was a statistically significant difference in diameters from the sinotubular junction to the proximal abdominal aorta, the largest was in the ascending aorta with a mean of 7.6 mm (standard deviation 4.5). This suggests that the ascending aortic diameter is a poor predictor of dissection in most patients.

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Ascending aortic diameter expands due to acute dissection.

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Post-dissection aortic diameters probably overestimate pre-dissection diameters.

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Following ascending dissection, diameter expansion is not limited to aorta ascendens.

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In this sample, estimated pre-dissection ascending aortic diameters were below 60 mm in 91% of patients and below 50 mm in 85%.