Prevalence and impact of HLA and MICA allele mismatching on donor-specific antibodies induction in kidney transplant rejection

AIM

Donor-recipient antigen mismatching for anti-human leucocyte antigen (HLA) and MICA is one of the risk factors for antibody induction leading to graft rejection. Our aim was to analyze the incidence and specificity of the different DSAs developing and to investigate the impact of HLA and MICA allele mismatches on antibody production in kidney transplant patients experiencing antibody-mediated rejection (AMR).

METHODS

We retrospectively reviewed 253 consecutive recipients of kidney transplant who were diagnosed as experiencing AMR.

RESULTS

Our results showed that around 27% of our patients were positive for DSAs over a median follow-up period of 24 months. Antibody to HLA-DQ7 was the most prevalent DSA detected. The allele mismatch number was significantly lower for DQ loci than -A and -B loci (DQ vs. A, p < .001; DQ vs. B, p = .002). Considering each HLA antigen, the incidence rate of DQ-DSA [41.9 (32.92-51.46; 95%CI)] was much higher than the rate observed for DSA directed to -A, -DR and -B loci. Half of the recipients in the DQ-DSA-only group, and the DQ-DSA together with non-DQ group, had MFI > 5000. Only one case developed de novo MICA-DSA (MICA002).

CONCLUSION

Our study indicates that mismatching for HLA and MICA alleles leads to the development of HLA and MICA antibodies in some kidney transplant recipients. We have also demonstrated that DSA to the DQ locus is the most prevalent in kidney transplant patients with AMR. Thus, matching the DQ locus in kidney allocation algorithms may reduce post-transplant development of DSA.

Use of the Tissue Common Rejection Module Score in Kidney Transplant as an Objective Measure of Allograft Inflammation

Long-term kidney transplant (KT) allograft outcomes have not improved as expected despite a better understanding of rejection and improved immunosuppression. Previous work had validated a computed rejection score, the tissue common rejection module (tCRM), measured by amplification-based assessment of 11 genes from formalin-fixed paraffin-embedded (FFPE) biopsy specimens, which allows for quantitative, unbiased assessment of immune injury. We applied tCRM in a prospective trial of 124 KT recipients, and contrasted assessment by tCRM and histology reads from 2 independent pathologists on protocol and cause biopsies post-transplant. Four 10-μm shaves from FFPE biopsy specimens were used for RNA extraction and amplification by qPCR of the 11 tCRM genes, from which the tCRM score was calculated. Biopsy diagnoses of either acute rejection (AR) or borderline rejection (BL) were considered to have inflammation present, while stable biopsies had no inflammation. Of the 77 biopsies that were read by both pathologists, a total of 40 mismatches in the diagnosis were present. The median tCRM scores for AR, BL, and stable diagnoses were 4.87, 1.85, and 1.27, respectively, with an overall significant difference among all histologic groups (Kruskal-Wallis, p < 0.0001). There were significant differences in tCRM scores between pathologists both finding inflammation vs. disagreement (p = 0.003), and both finding inflammation vs. both finding no inflammation (p < 0.001), along with overall significance between all scores (Kruskal-Wallis, p < 0.001). A logistic regression model predicting graft inflammation using various clinical predictor variables and tCRM revealed the tCRM score as the only significant predictor of graft inflammation (OR: 1.90, 95% CI: 1.40–2.68, p < 0.0001). Accurate, quantitative, and unbiased assessment of rejection of the clinical sample is critical. Given the discrepant diagnoses between pathologists on the same samples, individuals could utilize the tCRM score as a tiebreaker in unclear situations. We propose that the tCRM quantitative score can provide unbiased quantification of graft inflammation, and its rapid evaluation by PCR on the FFPE shave can become a critical adjunct to help drive clinical decision making and immunosuppression delivery.

A urine score for noninvasive accurate diagnosis and prediction of kidney transplant rejection

Accurate and noninvasive monitoring of renal allograft posttransplant is essential for early detection of acute rejection (AR) and to affect the long-term survival of the transplant. We present the development and validation of a noninvasive, spot urine-based diagnostic assay based on measurements of six urinary DNA, protein, and metabolic biomarkers. The performance of this assay for detecting kidney injury in both native kidneys and renal allografts is presented on a cohort of 601 distinct urine samples. The urinary composite score enables diagnosis of AR, with a receiver-operator characteristic curve area under the curve of 0.99 and an accuracy of 96%. In addition, we demonstrate the clinical utility of this assay for predicting AR before a rise in the serum creatinine, enabling earlier detection of rejection than currently possible by standard of care tests. This noninvasive, sensitive, and quantitative approach is a robust and informative method for the rapid and routine monitoring of renal allografts.

Optimizing Detection of Kidney Transplant Injury by Assessment of Donor-Derived Cell-Free DNA via Massively Multiplex PCR

Standard noninvasive methods for detecting renal allograft rejection and injury have poor sensitivity and specificity. Plasma donor-derived cell-free DNA (dd-cfDNA) has been reported to accurately detect allograft rejection and injury in transplant recipients and shown to discriminate rejection from stable organ function in kidney transplant recipients. This study used a novel single nucleotide polymorphism (SNP)-based massively multiplexed PCR (mmPCR) methodology to measure dd-cfDNA in various types of renal transplant recipients for the detection of allograft rejection/injury without prior knowledge of donor genotypes. A total of 300 plasma samples (217 biopsy-matched: 38 with active rejection (AR), 72 borderline rejection (BL), 82 with stable allografts (STA), and 25 with other injury (OI)) were collected from 193 unique renal transplant patients; dd- cfDNA was processed by mmPCR targeting 13,392 SNPs. Median dd-cfDNA was significantly higher in samples with biopsy-proven AR (2.3%) versus BL (0.6%), OI (0.7%), and STA (0.4%) (p < 0.0001 all comparisons). The SNP-based dd-cfDNA assay discriminated active from non-rejection status with an area under the curve (AUC) of 0.87, 88.7% sensitivity (95% CI, 77.7⁻99.8%) and 72.6% specificity (95% CI, 65.4⁻79.8%) at a prespecified cutoff (>1% dd-cfDNA). Of 13 patients with AR findings at a routine protocol biopsy six-months post transplantation, 12 (92%) were detected positive by dd-cfDNA. This SNP-based dd-cfDNA assay detected allograft rejection with superior performance compared with the current standard of care. These data support the feasibility of using this assay to detect disease prior to renal failure and optimize patient management in the case of allograft injury.

Mechanisms and biomarkers of immune quiescence in kidney transplantation

This review discusses the current understanding of biomarkers of immune quiescence based on reviews of published literature in kidney transplant operational tolerance and mechanistic studies based on a better characterization of the stable, well-functioning renal allograft.

A Comprehensive Analysis of the Current Status and Unmet Needs in Kidney Transplantation in Southeast Asia

To address the unmet needs in the face of a growing demand for end-stage renal failure management and kidney transplantation in Asia, we have conducted a critical analysis of published literature and national registries to evaluate clinical outcomes and the rates of organ donation in Southeast Asia and the challenges facing these regions with regards to regulation, choice of donor source, and funding. Based on the available data, suggestions are proposed for an advancement of rates of organ donation and access, with emphasis on improved regulation and public education.

Mortality and treatment costs of hospitalized chronic kidney disease patients between the three major health insurance schemes in Thailand

Background

Thailand has reformed its healthcare to ensure fairness and universality. Previous reports comparing the fairness among the 3 main healthcare schemes, including the Universal Coverage Scheme (UCS), the Civil Servant Medical Benefit Scheme (CSMBS) and the Social Health Insurance (SHI) have been published. They focused mainly on provision of medication for cancers and human immunodeficiency virus infection. Since chronic kidney disease (CKD) patients have a high rate of hospitalization and high risk of death, they also require special care and need more than access to medicine. We, therefore, performed a 1-year, nationwide, evaluation on the clinical outcomes (i.e., mortality rates and complication rates) and treatment costs for hospitalized CKD patients across the 3 main health insurance schemes.

Methods

All adult in-patient CKD medical expense forms in fiscal 2010 were analyzed. The outcomes focused on were clinical outcomes, access to special care and equipment (especially dialysis), and expenses on CKD patients. Factors influencing mortality rates were evaluated by multiple logistic regression.

Results

There were 128,338 CKD patients, accounting for 236,439 admissions. The CSMBS group was older on average, had the most severe co-morbidities, and had the highest hospital charges, while the UCS group had the highest rate of complications. The mortality rates differed among the 3 insurance schemes; the crude odds ratio (OR) for mortality was highest in the CSMBS scheme. After adjustment for biological, economic, and geographic variables, the UCS group had the highest risk of in-hospital death (OR 1.13;95 % confidence interval (CI) 1.07–1.20; p < 0.001) while the SHI group had lowest mortality (OR 0.87; 95 % CI 0.76–0.99; p = 0.038). The circumscribed healthcare benefits and limited access to specialists and dialysis care in the UCS may account for less favorable comparison with the CSMBS and SHI groups.

Conclusions

Significant differences are observed in mortality rates among CKD patients from among the 3 main healthcare schemes. Improvements in equity of care might minimize the differences.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1792-9) contains supplementary material, which is available to authorized users.

Non-HLA Antibodies in Clinical Transplantation

Organ transplantation overcomes conservative therapy to improve patient longevity. Despite the improvement of donor-recipient compatibility tests and intensified immunosuppressive agents, long-term graft survival remains poor because of acute and chronic injury driven by immunologic and non-immunologic factors. The significant immunological barrier for graft longevity is antibody-mediated rejection. Antibodies reactive to donor-specific human leukocyte antigens (HLA) have been shown to have adverse effects on the transplanted organ. However, there is minimal or controversial data supporting a pathogenic effect of antibodies against non-HLAs. This review discusses non-HLA antibodies and relevant antigen targets that have been uncovered by molecular medicine and correspond with acute rejection and chronic allograft injury. Updated proteomic evaluation may improve our knowledge of the immune response by enhancing immunologic epitope determination outside the scope of HLA.

Experiences on bedside Tenckhoff catheter implantation

OBJECTIVE

To clarify the outcome of a bedside technique of peritoneal dialysis (PD) catheter implantation which is practiced differently from worldwide guidelines in some points.

MATERIAL AND METHOD

This retrospective study was conducted in end stage renal diseases (ESRD) patients treated with chronic ambulatory peritoneal dialysis (CAPD). Catheter placement was initiated by the authors' bedside technique comprising no antibiotic prophylaxis, dry abdomen, and routinely right sided exit site as our protocol. All events within one month postimplantation, such as tip mal-position, malfunction, infection, and bleeding were analyzed.

RESULTS

One hundred and fourteen cases were participated with age, ranged from 14 to 78 yrs. Of the participating subjects, 38.5% was female and 60.52% was diabetes mellitus (DM). After 1 month, 113 out of 114 cases (99.1 %) accomplished CAPD. Of these, 79.8 % had good tip position and function after the break-in period. Early mal-position and poor flow was detected in 21 cases (18.4 %); 9 of them responded to laxative bowel stimulation while 12 cases needed surgical correction. Exit-site infection and/or wound infection were found in 7.9%. The peritonitis rate was 2.63%. All cases with infection were cured. Coagulase positive Staphylococcus aureus was the major causative organism.

CONCLUSION

Bedside Tenckhoff catheter implantation without antibiotic prophylaxis in dry abdomen is a safe modality for selected ESRD patients.