The Measurement of Donor-Specific Cell-Free DNA Identifies Recipients With Biopsy-Proven Acute Rejection Requiring Treatment After Liver Transplantation.

BACKGROUND: Assessment of donor-specific cell-free DNA (dscfDNA) in the recipient is emerging as a noninvasive biomarker of organ rejection after transplantation. We previously developed a digital polymerase chain reaction (PCR)-based approach that readily measures dscfDNA within clinically relevant turnaround times. Using this approach, we characterized the dynamics and evaluated the clinical utility of dscfDNA after liver transplantation (LT). METHODS: Deletion/insertion polymorphisms were used to distinguish donor-specific DNA from recipient-specific DNA. Posttransplant dscfDNA was measured in the plasma of the recipients. In the longitudinal cohort, dscfDNA was serially measured at days 3, 7, 14, 28, and 42 in 20 recipients. In the cross-sectional cohort, dscfDNA was measured in 4 clinically stable recipients (>1-y posttransplant) and 16 recipients (>1-mo posttransplant) who were undergoing liver biopsies. RESULTS: Recipients who underwent LT without complications demonstrated an exponential decline in dscfDNA. Median levels at days 3, 7, 14, 28, and 42 were 1936, 1015, 247, 90, and 66 copies/mL, respectively. dscfDNA was higher in recipients with treated biopsy-proven acute rejection (tBPAR) when compared to those without. The area under the receiver operator characteristic curve of dscfDNA was higher than that of routine liver function tests for tBPAR (dscfDNA: 98.8% with 95% confidence interval, 95.8%-100%; alanine aminotransferase: 85.7%; alkaline phosphatase: 66.4%; gamma-glutamyl transferase: 80.1%; and bilirubin: 35.4%). CONCLUSIONS: dscfDNA as measured by probe-free droplet digital PCR methodology was reflective of organ health after LT. Our findings demonstrate the potential utility of dscfDNA as a diagnostic tool of tBPAR.

Transfer of donor anti-HLA antibody expression to multiple transplant recipients: A potential variant of the passenger lymphocyte syndrome?

Antibody-mediated rejection, whereby transplant recipient B cells and/or plasma cells produce alloreactive anti-human leukocyte antigen (HLA) antibodies, negatively influences transplant outcomes and is a major contributor to graft loss. An early humoral immune response is suggested by the production of anti-HLA donor-specific antibodies (DSA) that can be measured using solid phase assays. We report the early posttransplant coexistence of a shared anti-HLA antibody profile in 5 solid organ transplant recipients who received organs from the same donor. Retrospective analysis of the donor's serum confirmed the presence of the same anti-HLA profile, suggesting the transfer of donor-derived anti-HLA antibodies, or the cells that produce them, to multiple solid organ transplant recipients. The time frame and extent of transfer suggest a novel variant of the passenger lymphocyte syndrome. These findings have important implications for the consideration of all posttransplant antibody measurements, particularly the interpretation of non-DSAs in the sera of transplant recipients.

A novel immune function biomarker identifies patients at risk of clinical events early following liver transplantation.

Balancing immunosuppression after liver transplant is difficult, with clinical events common. We investigate whether a novel immune biomarker based on a laboratory platform with widespread availability that measures interferon γ (IFNγ) after stimulation with a lyophilized ball containing an adaptive and innate immune stimulant can predict events following transplantation. A total of 75 adult transplant recipients were prospectively monitored in a blinded, observational study; 55/75 (73.3%) patients experienced a total of 89 clinical events. Most events occurred within the first month. Low week 1 results were significantly associated with risk of early infection (area under the receiver operating characteristic curve [AUROC], 0.74; P = 0.008). IFNγ ≤ 1.30 IU/mL (likelihood ratio positive, 1.93; sensitivity, 71.4%; specificity, 63.0%) was associated with the highest risk for infection with minimal rejection risk. Nearly half the cohort (27/60, 45.0%) expressed IFNγ ≤ 1.30 IU/mL. Moreover, an elevated week 1 result was significantly associated with the risk of rejection within the first month after transplant (AUROC, 0.77; P = 0.002), but no episodes of infection. On multivariate logistic regression, IFNγ ≥ 4.49 IU/mL (odds ratio, 4.75) may be an independent predictor of rejection (P = 0.05). In conclusion, low IFNγ suggesting oversuppression is associated with infections, whereas high IFNγ indicating undersuppression is associated with rejection. This assay offers the potential to allow individualization and optimization of immunosuppression that could fundamentally alter the way patients are managed following transplantation. Liver Transplantation 23 487-497 2017 AASLD.

Targeted individual prophylaxis offers superior risk stratification for cytomegalovirus reactivation after liver transplantation.

Cytomegalovirus (CMV) can reactivate following liver transplantation. Management of patients currently considered low risk based on pretransplant serology remains contentious, with universal prophylaxis and preemptive strategies suffering from significant deficiencies. We hypothesized that a CMV-specific T cell assay performed early after transplant as part of a preemptive strategy could better stratify "low-risk" (recipient seropositive) patients. We conducted a prospective, blinded, observational study in 75 adult recipients. QuantiFERON-cytomegalovirus was performed both before and at multiple times after transplant. Low-risk patients (n = 58) were monitored as per unit protocol and treatment was commenced if CMV > 1000 copies/mL (DNAemia). Twenty patients needed antiviral treatment for other reasons and were censored (mainly for rejection or herpes simplex virus infection); 19/38 (50%) of the remaining low-risk patients developed DNAemia at mean 34.6 days after transplant. A week 2 result of <0.1 IU/mL was significantly associated with risk of subsequent DNAemia (hazard ratio [HR], 6.9; P = 0.002). The positive predictive value of 80% suggests these patients are inappropriately labeled low risk and are actually at high likelihood of CMV reactivation. A secondary cutoff of <0.2 IU/mL was associated with moderate risk (HR, 2.8; P = 0.01). In conclusion, a protocol based on a single early CMV-specific T cell based assay would offer improved risk stratification and individualization of patient management after transplant. This could offer improved drug and service utilization and potentially result in significant improvements over both currently used protocols to manage supposedly low-risk patients.

Zoledronic acid prevents bone loss after liver transplantation: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Clinically important rapid bone loss occurs within 3 to 6 months after liver transplantation and may be associated with osteoporotic fractures. OBJECTIVE: To determine whether bisphosphonate treatment with zoledronic acid reduces transplant-related bone loss more than placebo in adults having liver transplantation for chronic liver disease. DESIGN: 12-month randomized, double-blind, placebo-controlled trial. SETTING: 2 large liver transplantation centers in Australia. PATIENTS: 62 adults having liver transplantation for chronic liver disease. INTERVENTIONS: Infusions of zoledronic acid, 4 mg (n = 32), or saline (n = 30) were given within 7 days of transplantation and again at months 1, 3, 6, and 9 after transplantation. All patients received supplementation with calcium carbonate, 600 mg/d, and ergocalciferol, 1000 U/d. MEASUREMENTS: The primary outcome was bone mineral density (BMD) measured by dual x-ray absorptiometry before transplantation and 3, 6, and 12 months later. Secondary outcomes included bone turnover markers that were measured before transplantation and 1, 3, 6, 9, and 12 months later. RESULTS: There were statistically significant interactions between treatment effects and time for BMD measurements at the lumbar spine (P = 0.002), femoral neck (P = 0.001), and total hip (P < 0.001). Differences in acute bone loss 3 months after transplantation favored zoledronic acid over placebo. Differences between groups in percentage change from baseline adjusted for baseline weight and serum parathyroid hormone (PTH) level were 4.0% (95% CI, 1.1% to 7.0%) for the lumbar spine, 4.7% (CI, 1.9% to 7.6%) for the femoral neck, and 3.8% (CI, 1.7% to 6.0%) for the total hip. At 12 months after transplantation, the difference in percentage change from baseline between the 2 groups adjusted for baseline weight and serum PTH level was 1.1% (CI, -2.1% to 4.4%) for the lumbar spine, 2.7% (CI, 0.0% to 5.4%) for the femoral neck, and 2.4% (CI, 0.1% to 4.7%) for the total hip. Treatment with zoledronic acid induced temporary secondary hyperparathyroidism and postinfusion hypocalcemia statistically significantly more often than did placebo. LIMITATIONS: The trial was not powered to assess fractures, and 10 of 62 (16%) patients were not included in adjusted analyses because of missing weight or serum PTH measurements. CONCLUSION: Treatment with zoledronic acid can prevent bone loss within the first year after liver transplantation.