Monitoring Of Renal Transplant Recipients Research Articles

Analysis of Uric Acid and other Factors affecting Renal Function in the Monitoring of Renal Transplant Recipients

Analysis of Uric Acid and other Factors affecting Renal Function in the Monitoring of Renal Transplant Recipients

A Significant Role for Anti–Human Leukocyte Antigen Antibodies and Antibody-Mediated Rejection in the Biopsy-for-Cause Population

The role of anti–human leukocyte antigen (HLA) antibodies and antibody-mediated rejection is well known, but our comprehension and the preventive measures we take seem to be insufficient. One of the major causes of premature renal transplant loss is recepients' immunologic hyperactivity to donors' antigens. Monitoring of humoral alloreactivity gives hope for early diagnosis and adequate therapy. The goal of our analysis was the assessment of the influence of anti-HLA antibodies on the function and survival of transplants. In our study we included 60 consecutive renal transplant recipients who had a renal transplant biopsy-for-cause performed due to insufficiency. Transplant biopsies were performed between the 7th day and 12th year (median, 2 years) after transplantation. Anti-HLA antibodies were present in 20 patients (33%). The patients were divided into 2 groups according the presence of anti-HLA antibodies. In a 12-month observation, 10/20 (50%) patients in the anti-HLA(+) group returned to dialysis in contrast with 7/40 (17.5%; P = .014) in the anti-HLA(−) group. Also, 8/10 (80%) of the anti-HLA(+) patients who lost the transplant had anti-HLA Abs class II and only 2/10 (20%) had anti-HLA Abs class I. Anti-HLA antibodies were specific to a donor (donor-specific antibodies [DSA]) in 8/10 (80%) of the patients who lost the transplant. Anti-HLA antibodies appeared de novo in 50% of patients who lost the transplant. Nonadherence was suspected in 50% of patients. Acute humoral rejection occurred in 1 patient. Also, 8/10 (90%) developed chronic active humoral rejection. Our study revealed that graft loss in the renal transplant biopsy-for-cause population with the presence of anti-HLA Abs during a 12-month observation reached 50%. Nonadherence in these patients was very high and amounted to 50%. Monitoring of renal transplant recipients and individualization of therapy considering humoral activity should prolong renal graft survival.

Pattern of Malignancy in Living Donor Kidney Transplant Recipients.

Background: Differences exist in the pattern of malignancy in different population groups. Most reports of malignancy have come from deceased donor transplant recipients from developed countries. Material and methods: In a retrospective analysis of 2000 patients who underwent live renal transplantation last 30 yrs (1983-2013), age, sex, type of immunosuppression, interval between transplantation and diagnosis of cancer was recorded. Results: Thirty-nine (1.95%) patients (27 M:12 F) developed 43 malignancies including 29(67.4%) with PTLD and 15 (34.8%) had other carcinomas. Five patients had dual malignancy. Mean age: 40.2 years (range 21 to 62 yrs), mean interval post-transplant was 57.9 mo (3 to 144). Of these 29 patients (1.45%) with PTLD (22M,7 F) 22 (75.8%) patients developed NHL and 7 patients (24.2%) had myeloma. Diagnosis was made by biopsy of the involved organ in 21 patients (72.4%) and aspiration cytology in 5 patients (17.2%). In 3 patients, the diagnosis was made only at autopsy. Only 5 patients (17.2%) developed PTLD within a year of transplantation. Twelve patients developed PTLD 1-5 years and 12 patients 5-10 years after transplantation. Organ involvement was extra-nodal in 18 patients (82%). Thirteen (59%) patients had disseminated disease and 9 (36.4%) had localized involvement of a single organ (brain-3, liver-1, allograft-1, perigraft node-1, retroperitoneal lymph nodes-3). Infiltration of graft was noted in 2 patients. Patients with plasma cell myeloma presented with backache, pathological fracture, unexplained anaemia or graft dysfunction. PTLD was of B cell origin in 20 cases (70%). CD 20 staining was done in 10 recent cases, of which 8 stained positive. Of the 26 patients diagnosed during life, 20 (69%) died within 1 year of diagnosis. All the other cancers were seen after 1 yr of transplant. All the patients with above cancers were managed by stopping antiproliferatives and continuing steroids and managed surgically. Initial immunosuppressive therapy consisted of cyclosporine (CsA), azathioprine(Aza) and prednisolone in 27 patients, only Aza and prednisolone in 8 patients, tacrolimus (Tac), Aza and prednisolone in 2 and Tac, MMF and prednisolone in 2 patients. Conclusion: Although the incidence of post-transplant malignancies was low, careful monitoring of renal transplant recipients for malignancies is required due to the poor response to treatment.

Combined Measurement of Serum DNA and Urine VP1 Messenger RNA in Monitoring BK Virus Replication in Kidney Graft Recipients

Evaluation of BK virus replication is a fundamental tool in the monitoring of renal transplant recipients. Herein, we investigated the role of urine VP1 messenger RNA (mRNA) quantification and combined measurement of serum DNA and urine VP1 mRNA in 428 kidney allograft recipients. BK viremia and viruria were detected in 24 (5.6%) and 54 (12.6%) patients, respectively. A diagnosis of BKV-associated nephropathy (BKVAN) was established in 2 patients, both within the first year posttransplantation. Based on urine VP1 mRNA measurement, BKV replication was observed in 10 (2.1%) patients, 2 of whom displayed BKVAN. Urine VP1 mRNA was detected in all cases in association with viremia except 5 and in all cases with viruria. No difference among VP1 mRNA levels was noted between the 2 BKVAN patients and the highest values in patients without BKVAN. The urine VP1 mRNA result by analysis using the operating characteristics was not superior to viremia, despite the improvement obtained with the combined measurement of viremia (cut-off, 16,000 copies/mL) and urine VP1 mRNA (>10,000 copies/10 3 cells). In conclusion, VP1 mRNA measurements may complement viremia and viruria to monitor BKV replication, although its use is limited by its technical complexity in comparison with DNA detection.

113-P: A new non-invasive tool in follow-up monitoring of renal transplant recipients

113-P: A new non-invasive tool in follow-up monitoring of renal transplant recipients

Immunological Monitoring of Renal Transplant Recipients to Predict Acute Allograft Rejection Following the Discontinuation of Tacrolimus

BackgroundTransplant patients would benefit from reduction of immunosuppression providing that graft rejection is prevented. We have evaluated a number of immunological markers in blood of patients in whom tacrolimus was withdrawn after renal transplantation. The alloreactive precursor frequency of CD4+ and CD8+ T cells, the frequency of T cell subsets and the functional capacity of CD4+CD25+FoxP3+ regulatory T cells (Treg) were analyzed before transplantation and before tacrolimus reduction. In a case-control design, the results were compared between patients with (n = 15) and without (n = 28) acute rejection after tacrolimus withdrawal.Principal FindingsPrior to tacrolimus reduction, the ratio between memory CD8+ T cells and Treg was higher in rejectors compared to non-rejectors. Rejectors also had a higher ratio between memory CD4+ T cells and Treg, and ratios <20 were only observed in non-rejectors. Between the time of transplantation and the start of tacrolimus withdrawal, an increase in naive T cell frequencies and a reciprocal decrease of effector T cell percentages was observed in rejectors. The proportion of Treg within the CD4+ T cells decreased after transplantation, but anti-donor regulatory capacity of Treg remained unaltered in rejectors and non-rejectors.ConclusionsImmunological monitoring revealed an association between acute rejection following the withdrawal of tacrolimus and 1) the ratio of memory T cells and Treg prior to the start of tacrolimus reduction, and 2) changes in the distribution of naive, effector and memory T cells over time. Combination of these two biomarkers allowed highly specific identification of patients in whom immunosuppression could be safely reduced.

Evaluation of the Immuknow-immune function assay as a new parameter in immune monitoring of renal transplant recipients

Evaluation of the Immuknow-immune function assay as a new parameter in immune monitoring of renal transplant recipients

Transplant: immunology and treatment of rejection

Transplant: immunology and treatment of rejection

Non-Invasive Monitoring of Renal Transplant Recipients: Urinary Excretion of Soluble Adhesion Molecules and of the Complement-Split Product C4d

Background: The number of inducible adhesion molecules known to be involved in cell-mediated allograft rejection is still increasing. In addition, recent data describe complement activation during acute humoral allograft rejection. The aim of this study was to assess whether specific molecules from either pathway are excreted into urine and whether they can provide useful diagnostic tools for the monitoring of renal transplant recipients. Methods: Urinary concentrations of soluble adhesion molecules (sICAM-1, sVCAM-1) and of the complement degradation product C4d were determined by standardized ELISA technique in 75 recipients of renal allografts and 29 healthy controls. Patient samples were assigned to four categories according to clinical criteria: group 1: acute steroid-sensitive rejection (ASSR, n = 14), group 2: acute steroid-resistant rejection (ASRR, n = 12), group 3: chronic allograft dysfunction (CAD, n = 20) and group 4: stable graft function (SGF, n = 29). Results: All patients with rejection episodes (groups 1–3) had significantly higher values of urinary sC4d compared with healthy controls and patients with stable graft function (p < 0.05). The urinary levels of sVCAM-1 were significantly higher in group 2 (ASRR) compared with all other groups (p < 0.001). Uniformly low amounts of s-VCAM-1 and complement-split product C4d were excreted by healthy controls (group 0). In contrast, urinary sICAM-1 concentration in healthy controls was almost as high as in group 2 (ASRR) whereas patients with a stable functioning graft (group 4) excreted significantly less sICAM-1 (p < 0.05). Conclusion: The evaluation of sVCAM-1 and sC4d excretion in urine can provide a valuable tool with regard to the severity and type of allograft rejection. With respect to long-term allograft survival, serial measurements of these markers should have the potential to detect rejection episodes and prompt immediate treatment.

Comparative evaluation of ‘TaqMan’ RT-PCR and RT-PCR ELISA for immunological monitoring of renal transplant recipients

By sequentially monitoring cytokine gene expression (using RT-PCR ELISA technology) in peripheral blood cells of renal transplant recipients in the early post-operatively period we have shown that expression patterns correlate with clinical events, namely acute allograft rejection. This strategy may have the potential of predicting acute rejection prior to clinical detection. Unfortunately, the technique used was time consuming and only semi-quantitative and, therefore, not suitable for clinical application. In this study, we have sought to confirm the results of the early work using a real time quantitative RT-PCR technique (‘TaqMan’), which may be applicable in the clinical laboratory. ‘TaqMan’ primers and probes were designed for Interleukin (IL)-4 and IL-10 using Primer Express software. Cytokine gene expression for both cytokines was re-measured in stored cDNA samples from 27 non-rejectors and 14 patients experiencing an episode of biopsy proven acute rejection. Compared to pre-transplant levels, IL-4 gene expression fell significantly on post-operative days 2 and 7 before returning to baseline values by day 14 in the non-rejectors. In the rejectors, the initial significant fall was again seen, but with an earlier return to pre-transplant levels at the time of rejection diagnosis. This was followed by a further significant fall in levels 48 h after the initiation of anti-rejection therapy. These different patterns for rejectors and non-rejectors were seen using both techniques. For IL-10, gene expression increased significantly following transplantation throughout the study period when compared to baseline values. This pattern was seen using both techniques. In the rejectors, there were different patterns seen depending on the technique used. When using RT-PCR ELISA, the initial rise was again seen followed by a return to baseline values at the time of rejection diagnosis followed by a further significant rise in gene expression after the start of anti-rejection treatment. The pattern resembled those of the non-rejectors when expression was measured using ‘TaqMan’. This study has confirmed that sequential monitoring of cytokine gene expression, measured in peripheral blood mononuclear cells, detects significant changes that correlate with clinical events in renal transplant recipients, including acute rejection, although not all changes detected with RT-PCR ELISA were confirmed. Therefore, real time quantitative RT-PCR technology may be useful in monitoring the immunological status of these patients in the early post-operative period.

Assessment of soluble adhesion molecules (sICAM-1, sVCAM-1, sELAM-1) and complement cleavage products (sC4d, sC5b-9) in urine. Clinical monitoring of renal allograft recipients.

Increasing evidence exists that inducible adhesion molecules are involved in cell-mediated allograft rejection. In addition, complement activation during rejection has been described. This study investigated, whether specific molecules derived from either pathway are excreted into urine during rejection and whether they can provide useful diagnostic tools for the monitoring of renal transplant recipients. Urinary concentrations of soluble adhesion molecules (sICAM-1, sVCAM-1, sE-selectin) and of complement cleavage products (sC4d and sC5b-9), were determined by standardized ELISA in 30 normal controls and 80 samples from 49 recipients of renal allografts. In contrast to the low amounts of adhesion molecules and complement components uniformly excreted by healthy persons (group 0), marked differences were observed among allograft recipients. To prove the clinical relevance of these differences in excretion, patient samples were assigned to 5 categories according to clinical and histopathological criteria: group I--acute steroid-resistant rejection (n = 10); group II--acute steroid-sensitive rejection (n = 10); group III--chronic rejection (n = 23); group IV--stable graft function (n = 27); and group V--miscellaneous disorders (n = 10), including infections, CsA overdoses, and glomerulonephritis. Urinary levels of sICAM-1, sVCAM-1, and sC4d were significantly higher in group I compared with all other groups (P < 0.01). The difference in sICAM-1 excretion between groups III and IV also reached statistical significance (P < 0.05). Urinary concentrations of sICAM-1, sVCAM-1, and sC4d were reflective of their histological distribution in corresponding graft biopsies. None of the patients excreted E-selectin in detectable amounts. Excretion of the terminal membrane attack complex C5b-9 was not significantly associated with any diagnosis. It is concluded that for clinical purposes the combined evaluation of sICAM-1, sVCAM-1, and sC4d is most useful and can provide valuable information with regard to the severity and the type of allograft rejection.

Possibilities and pitfalls of indium-111 platelet scintigraphy in the monitoring of renal transplant recipients.

During the last four years, we have performed two studies on the clinical application of 111In-platelet scintigraphy after renal transplantation. In the first study, we collected 75 patients who were treated with prednisolone and azathioprine. The platelet deposition in the graft was expressed as a platelet-uptake index (PUI). The results suggested that the platelet scan was a valuable tool for early detection of acute graft rejection, which was indicated by an increase in PUI. Quite different results were obtained in 50 patients immunosuppressed with cyclosporin A (CSA) and prednisolone. Acute interstitial rejection escaped detection by this diagnostic procedure. Significant elevations of PUI were observed in acute vascular rejection and microvascular CSA nephrotoxicity, resembling the haemolytic uraemic syndrome (HUS) only. Therefore, platelet deposition in the graft can be regarded as a non-specific phenomenon, occurring in two entities which require completely different therapeutic approaches. In spite of the monitoring by means of the platelet scan, percutaneous biopsy is still necessary for differential diagnosis of graft dysfunction.