The Pathologic Impact of Tacrolimus on Protocol Biopsy in Renal Transplant Patients With Basiliximab-Based Immunosuppression

KDIGO clinical practice guideline for the care of kidney transplant recipients

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially on the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.

The utility of 1- and 3-month protocol biopsies on renal allograft function: a randomized controlled study

Identification of pathological events in the renal allograft using protocol biopsies at predetermined time intervals may yield useful information and improve outcomes. We examined the influence of decisions taken on the basis of 1- and 3-month protocol biopsies findings on 1-year renal allograft function in a prospective randomized study. Out of 102 living-donor allograft recipients, 52 were randomized to undergo protocol biopsies and 50 controls had only indicated biopsies. All acute rejection (AR) episodes (clinical and subclinical) were treated. Calcineurin inhibitor (CNI) dose adjustments were made on clinical judgment. Baseline recipient and donor characteristics, immunosuppressive drug usage, HLA matches and 2-h cyclosporine levels were similar in both groups. At 1 and 3 months, protocol biopsies revealed borderline (BL) changes in 11.5% and 14% patients, AR in 17.3% and 12% and chronic allograft nephropathy (CAN) in 3.8% and 10%. The incidence of clinically evident AR episodes was similar in the two groups, but biopsy group had lower serum creatinine at 6 months (p = 0.0003) and 1 year (p < 0.0001). The renal functions were similar in those with normal histology and BL changes. Protocol biopsies are helpful in detecting subclinical histological changes in the graft and improving short-term renal allograft function.

Validation of a Liquid Chromatography-Mass Spectrometric Assay for Tacrolimus in Liver Biopsies After Hepatic Transplantation: Correlation With Histopathologic Staging of Rejection

The aims of this work were both to validate a sensitive and specific method to quantify tacrolimus (TAC) in liver biopsies after hepatic transplantation and to evaluate the predictive value of either tissue or blood TAC concentrations for rejection in 146 adult patients under a TAC-based immunosuppression. Trough blood levels were monitored daily during the hospital stay by immunoassay. Liver biopsies were routinely performed at day 7 posttransplantation. The tissue assay was developed by liquid chromatography-mass spectrometry. The limit of quantification was 5 pg/mg, with intra- and interassay precision ranging from 3.9% to 14.3% and 4.7% to 15.9%, respectively. The extraction efficiency was approximately 80%. TAC found in liver biopsies ranged from less than 5 up to 387 pg/mg. Blood TAC levels ranged from 2.7 to 19.3 ng/mL. Tissue levels displayed excellent correlation with liver histopathologic BANFF rejection score, whereas blood levels did not. Clinically significant rejections (BANFF scores > or = 6) were characterized by mean TAC tissue and blood concentration of 13.1 pg/mg and 7.6 ng/mL, respectively, whereas these mean values became, respectively, 74.9 pg/mg (P < 0.05) and 7.1 ng/mL (not significant) for nonclinically significant rejection episodes (BANFF < 6). In this study, hepatic tissue TAC concentrations were distributed in a wider range and displayed a significantly better correlation with the severity of the organ rejection than predose blood levels. A tissue TAC concentration less than 30 pg/mg is 89% sensitive and 98% specific to discriminate clinically significant cellular rejection. Further studies are required to better understand the factors affecting TAC distribution within liver tissue (such as carrier proteins and cytochrome genetic polymorphism, liver function, age, hepatic blood flow, type of organ transplanted, time posttransplantation) and to define its value in the treatment of liver allograft rejection.

Kidney NGAL is a novel early marker of acute injury following transplantation

Acute kidney injury secondary to ischemia-reperfusion in renal allografts often results in delayed graft function. We tested the hypothesis that expression of neutrophil gelatinase-associated lipocalin (NGAL) is an early marker of acute kidney injury following transplantation. Sections from paraffin-embedded protocol biopsy specimens obtained at approximately one hour of reperfusion after transplantation of 13 cadaveric (CAD) and 12 living-related (LRD) renal allografts were examined by immunohistochemistry for expression of NGAL. The staining intensity was correlated with cold ischemia time, peak post-operative serum creatinine, and dialysis requirement. There were no differences between the LRD and CAD groups in age, gender or preoperative serum creatinine. Using a scoring system of 0 (no staining) to 3 (most intense staining), NGAL expression was significantly increased in CAD specimens (2.3+/-0.8 versus 0.8+/-0.7 in LRD, p<0.001). There was a strong correlation between NGAL staining intensity and cold ischemia time (R=0.87, p<0.001). Importantly, NGAL staining in these early CAD biopsies was strongly correlated with peak postoperative serum creatinine, which occurred days later (R=0.86, p<0.001). Four patients developed delayed graft function requiring dialysis during the first week posttransplantation; all of these patients displayed the most intense NGAL staining in their first protocol biopsies. We conclude that NGAL staining intensity in early protocol biopsies represents a novel predictive biomarker of acute kidney injury following transplantation.