Clinical and pathological analyses of interstitial fibrosis and tubular atrophy cases after kidney transplantation

Monitoring of Soluble Forms of BAFF System (BAFF, APRIL, sR-BAFF, sTACI and sBCMA) in Kidney Transplantation

BAFF system plays an essential role in B cells homeostasis and tolerance, although it has widely not been tested in transplantation with doubtful results. The main purpose was to study the BAFF soluble forms and their correlation with acute rejection (AR) and donor-specific antibodies production. Serum levels of BAFF, APRIL, and soluble forms of their receptors were analyzed in renal recipients with and without acute rejection (AR/NAR) appearance. All molecules were evaluated at pre- and post-transplantation. sTACI showed a significant correlation with BAFF and sR-BAFF levels, and sBCMA also showed a positive correlation with sAPRIL levels. A significant increase in sAPRIL levels in patients suffering AR was also found, and ROC curves analysis showed an AUC = 0.724, a concentration of 6.05 ng/ml (sensitivity: 66.7%; specificity: 73.3%), the best cutoff point for predicting AR. In the post-transplant dynamics of sAPRIL levels in the longitudinal cohort, we observed a significant decrease at 3 and 6 month post-transplantation compared to pretransplantation status. We also observed that recipients with high pre-transplant levels of sAPRIL generated antibodies earlier than those with lower sAPRIL levels, although their long-term post-transplantation was not different. Our results show that elevated serum levels of APRIL may be helpful as a biomarker for the diagnosis of AR, although the longitudinal study shows that it is not helpful as a prognostic biomarker.

Rate, Factors, and Outcome of Delayed Graft Function After Kidney Transplantation of Deceased Donors

BACKGROUND

Delayed graft function (DGF) is a frequent complication after kidney transplantation affecting long-term outcome.

PATIENTS AND METHODS

A total of 525 consecutive recipients (age 54.2 ± 13.4 years, 33% female) of kidneys from deceased donors transplanted between 2005 and 2012 were retrospectively examined. DGF was defined as the need of dialysis within the first week after transplantation.

RESULTS

DGF developed in 21.1% (n = 111). Factors associated with DGF (P ≤ .035, respectively) were recipient body mass index, C-reactive protein of the recipient, residual diuresis, cold ischemia time, donor age, and diuresis in the first hour after transplantation. Median duration of DGF was 16 (2-66) days. Patients after DGF had a significantly lower GFR compared with recipients without DGF either after 3 (32.9 ± 16.5 vs 46.3 ± 18.4 mL/min/1.73 m²) or after 12 months (38.9 ± 19.3 vs 48.6 ± 20.4 mL/min/1.73 m², P < .001, resp.). During DGF, 12.4% developed BANFF II and 18.0% BANFF I rejection, 20.2% had signs of transplant glomerulitis (first biopsy), and 16.2% (n = 18) remained on dialysis.

CONCLUSION

DGF affects 1 out of 5 kidney transplants from deceased donors. Minimizing modifiable risk factors, in particular immunologic risk, may ameliorate the incidence and outcome of DGF. The outcome of DGF depends mainly on the diagnosis of any rejection and worsens upon detection of transplant glomerulitis and pronounced interstitial fibrosis and tubular atrophy (IFTA).

Acute Rejection After Kidney Transplantation Associates With Circulating MicroRNAs and Vascular Injury

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Background

Acute rejection (AR) of kidney transplants is associated with the loss of endothelial integrity, microvascular rarefaction and, ultimately, graft dysfunction. Circulating angiogenic microRNAs (miRNAs) may serve as markers for microvascular injury. Here, we investigated the short- and long-term effects of AR after kidney transplantation on systemic vascular injury and the associated circulating miRNA profile.

Methods

Systemic vascular injury was determined by measuring capillary tortuosity and density within the oral mucosa as well as by assessing circulating levels of angiopoietin-2/angiopoietin-1 ratio, vascular endothelial growth factor and soluble thrombomodulin. After a pilot study, we selected 48 miRNAs to assess the AR- and microvascular injury associated circulating miRNAs.

Results

In stable transplant recipients (n = 25) and patients with AR (n = 13), which were also studied longitudinally (1, 6, and 12 months post-AR), we found an AR-associated increase in markers of systemic vascular injury, of which vascular endothelial growth factor and soluble thrombomodulin normalized within 1 year after AR. Of the 48 selected miRNAs, 8 were either decreased (miR-135a, miR-199a-3p, and miR-15a) or increased (miR-17, miR-140-3p, miR-130b, miR-122 and miR-192) in AR. Of these, miR-130b, miR-199a, and miR-192 associated with markers of vascular injury, whereas miR-140-3p, miR-130b, miR-122, and miR-192 normalized within 1 year after AR.

Conclusions

AR after kidney transplantation is characterized by systemic microvascular injury and associates with specific circulating miRNA levels.