Associations between Deceased-Donor Urine MCP-1 and Kidney Transplant Outcomes

Introduction

Existing methods to predict recipient allograft function during deceased-donor kidney procurement are imprecise. Understanding the potential renal reparative role for monocyte chemoattractant protein-1 (MCP-1), a cytokine involved in macrophage recruitment after injury, might help to predict allograft outcomes.

Methods

We conducted a substudy of the multicenter prospective Deceased Donor Study cohort that evaluated deceased kidney donors from 5 organ procurement organizations from May 2010 to December 2013. We measured urine MCP-1 (uMCP-1) concentrations from donor samples collected at nephrectomy to determine associations with donor acute kidney injury (AKI), recipient delayed graft function (DGF), 6-month estimated glomerular filtration rate (eGFR), and graft failure. We also assessed perfusate MCP-1 concentrations from pumped kidneys for associations with DGF and 6-month eGFR.

Results

AKI occurred in 111 donors (9%). The median (interquartile range) uMCP-1 concentration was higher in donors with AKI compared with donors without AKI (1.35 [0.41–3.93] ng/ml vs. 0.32 [0.11–0.80] ng/ml, P < 0.001). DGF occurred in 756 recipients (31%), but uMCP-1 was not independently associated with DGF. Higher donor uMCP-1 concentrations were independently associated with a higher 6-month eGFR in those without DGF (0.77 [0.10–1.45] ml/min per 1.73 m² per doubling of uMCP1). However, there were no independent associations between uMCP-1 and graft failure over a median follow-up of ∼2 years. Lastly, perfusate MCP-1 concentrations significantly increased during pump perfusion but were not associated with DGF or 6-month eGFR.

Discussion

Donor uMCP-1 concentrations were modestly associated with higher recipient 6-month eGFR in those without DGF. However, the results suggest that donor uMCP-1 has minimal clinical utility given no associations with graft failure.

Characteristics and Evaluation of Geographically Distant vs Geographically Nearby Living Kidney Donors

BACKGROUND

Living donor kidney transplant (LDKT) can be impeded by multiple barriers. One possible barrier to LDKT is a large physical distance between the living donor's home residence and the procuring transplant center.

METHODS

We performed a retrospective, single-center study of living kidney donors in the United States who were geographically distant (residing ≥150 miles) from our transplant center. Each distant donor was matched to 4 geographically nearby donors (<150 miles from our center) as controls.

RESULTS

From 2007 to 2010, of 429 live kidney donors, 55 (12.8%) were geographically distant. Black donors composed a higher proportion of geographically distant vs nearby donors (34.6% vs 15.5%), whereas Hispanic and Asian donors composed a lower proportion (P = .001). Distant vs nearby donors had similar median times from donor referral to actual donation (165 vs 161 days, P = .81). The geographically distant donors lived a median of 703 miles (25% to 75% range, 244 to 1072) from our center and 21.2 miles (25% to 75% range, 9.8 to 49.7) from the nearest kidney transplant center. The proportion of geographically distant donors who had their physician evaluation (21.6%), psychosocial evaluation (21.6%), or computed tomography angiogram (29.4%) performed close to home, rather than at our center, was low.

CONCLUSIONS

Many geographically distant donors live close to transplant centers other than the procuring transplant center, but few of these donors perform parts of their donor evaluation at these closer centers. Black donors comprise a large proportion of geographically distant donors. The evaluation of geographically distant donors, especially among minorities, warrants further study.

Fatal graft-versus-host disease presenting as fever of unknown origin in a pancreas-after-kidney transplant recipient

Acute graft-versus-host disease (GVHD) is a rare complication of pancreas transplantation. We describe a 54-year-old male with type 1 diabetes who received a zero-antigen mismatched pancreas-after-kidney transplant from a pancreas donor who was homozygous at the HLA-B, -Cw, -DR, and -DQ alleles. Starting on postoperative day (POD) #22, the patient developed persistent fevers. Workup was notable only for low-grade cytomegalovirus viremia, which was treated. The fevers eventually disappeared. On POD #106, the patient was noted to have a diffuse erythematous rash. A skin biopsy was consistent with GVHD. Short tandem repeat DNA analysis of both peripheral blood lymphocytes and skin demonstrated mixed chimerism, confirming the diagnosis of GHVD. Soon after diagnosis, the patient developed pancytopenia and fevers and died of multiorgan failure on POD #145. Transplant clinicians should consider GVHD as a possible, although admittedly rare, cause of fevers of unknown origin in recipients of pancreas transplants.

Renal transplantation in patients with pre-transplant donor-specific antibodies and negative flow cytometry crossmatches

The clinical significance of pre-transplant donor-specific antibodies (DSA), despite negative cytotoxicity and flow cytometry crossmatches (FCXMs), is unknown. We performed a retrospective cohort study of 60 living donor renal transplant recipients, all with pre-transplant cytotoxicity and T-cell and B-cell FCXMs that were negative. Twenty recipients had pre-transplant DSA detected by enzyme-linked immunosorbent assays (ELISA) and/or microbead methods. Forty contemporaneous DSA-negative controls were selected. In the DSA-positive group, after a median follow-up of 8.2 months (25-75% range, 5.4-22.8 months), patient survival was 100% and allograft survival was 95.0%. Acute humoral rejection (AHR) developed in four patients (20.0%). Three of the AHR episodes occurred within the first month post-transplant. Median serum creatinine at last follow-up was 1.3 mg/dL (25-75% range, 1.0-1.6 mg/dL), versus 1.1 mg/dL (25-75% range, 0.9-1.4 mg/dL) in the DSA-negative controls (p = 0.29). Only one of the 40 controls developed AHR (2.5%). Pre-transplant DSA was associated with a significantly increased incidence of AHR (p = 0.02 by log-rank test). In conclusion, despite negative pre-transplant cytotoxicity and FCXMs, renal transplant recipients with pre-transplant DSA detected by solid-phase methods may have an increased incidence of AHR and require close monitoring post-transplant.