A new model to determine Optimal Exposure to Tacrolimus and Mycophenolate Mofetil after renal transplantation.

BACKGROUND: Drug dosing for Tacrolimus (TAC) and Mycophenolate Mofetil (MMF) after kidney transplantation remains challenging. Therapeutic drug monitoring (TDM) offers a means to individualize drug dosing and improve outcomes. METHODS: In this observational study, patients having mycophenolic acid (MPA) exposure assessed by limited sampling strategy (LSS) within the first 6 months were included and followed for 1 year. RESULTS: A total of 113 clinical events occurring in 110 patients were classified into 3 groups: Group 1 Stable (n = 34), Group 2 Over drug exposed (n = 64) having infections or drug toxicity and Group 3 Under drug exposed (n = 15) developing rejection or de novo donor-specific alloantibodies. Although TAC levels, MMF dose, MPA, and MPA Glucuronide (MPAG) exposure, expressed as area under curve (AUC), individually failed to predict outcomes, a scoring model incorporating all 3 drug levels TAC TDM × (MPA AUC + MPAG/10 AUC) correctly classified outcomes. A score over 1071 had a sensitivity and specificity of 0.94 (95% CI 0.56-0.83) and 0.84 (95% CI 0.69-0.89) for over exposure. A score below 625 had a sensitivity and specificity of 0.76 (95% CI 0.53-0.93) and 0.80 (95% CI 0.41-0.70) for under exposure. CONCLUSIONS: This integrated model of assessing TAC and MMF exposure may facilitate individualized therapy.

Simultaneous Pancreas and Kidney Transplantation-Is It a Treatment Option for Patients With Type 2 Diabetes Mellitus? An Analysis of the International Pancreas Transplant Registry.

PURPOSE OF REVIEW: Pancreas transplantation remains the best long-term treatment option to achieve euglycemia and freedom from insulin in patients with labile diabetes mellitus. It is an approved procedure for type 1 (T1DM), but it is still considered controversial for type 2 diabetes mellitus (T2DM). RECENT FINDINGS: This study analyzed all primary deceased donor pancreas transplants in patients with T2DM reported to IPTR/UNOS between 1995 and 2015. Characteristics, outcomes, and risk factors over time were determined using univariate and multivariate methods. The focus was on simultaneous pancreas/kidney (SPK) transplants, the most common pancreas transplant category. Patient, pancreas, and kidney graft survival rates increased significantly over time and reached 95.8, 83.3, and 91.1%, respectively, at 3 years posttransplant for transplants performed between 2009 and 2015. SPK is a safe procedure with excellent pancreas and kidney graft outcome in patients with T2DM. The procedure restores euglycemia and freedom from insulin and dialysis. Based on our results, SPK should be offered to more uremic patients with labile T2DM.

Combined induction therapy with rabbit antithymocyte globulin and rituximab in highly sensitized renal recipients.

Compared to non-sensitized renal transplant recipients, patients with preformed alloantibodies are at greater risk of cellular and humoral rejection and premature graft failure. We explored the effects of adding B-cell depleting agent (rituximab) to standard rabbit anti-thymocyte globulin (rATG) induction regimen for patients with panel reactive antibody levels >50%. Following induction therapy, 14 recipients were given two doses of rituximab (375 mg/m(2)) within the first month post-transplantation. Their long-term outcomes were compared to a historical control group of 23 recipients who received rATG alone. Graft survival at 5 years was superior with combination therapy compared to induction therapy alone (92.9 versus 48.3%, respectively, p = 0.02). While 30% of the rATG alone group experienced cellular rejection and 26% humoral rejection, none of rituximab plus rATG renal transplant recipients group had rejection. Thus, addition of rituximab to rATG provided superior outcomes to rATG alone. This combination induction therapy should be considered for a high-risk population.

The increasing clinical importance of alloantibodies in kidney transplantation.

Historically, cellular rather than humoral immunity has gathered the most attention in kidney transplantation. As the specter of cellular acute rejection and early graft loss has faded due to the availability of highly effective immunosuppressive therapy, scientific and clinical studies now focus on improving long-term graft survival. It is increasingly appreciated that alloantibodies directed against HLA and non-HLA antigens are key factors in determining graft longevity. Significant efforts are now being made to better understand the critical impact that B cells and alloantibodies make on organ allocation and graft survival. Future therapies directed specific for the humoral alloresponse will undoubtedly lead to improved outcomes after kidney transplantation. This review will cover some of the advances in the understanding and management of the continuum of humoral immunity in renal transplantation in the pre, peri and post-transplant periods.

Induction therapy in renal transplant recipients: a review.

Transplant science has improved significantly over the last decade. Influenced by novel advancements, rejection rates and short-term graft losses diminished substantially. Induction therapy was shown to reduce rejection rates and improve short-term graft survival. In this article, we discuss the most commonly used induction agents and the choice of induction therapy in different renal transplant recipient subgroups. The medical literature as well as our own experience was used to prepare this review. At this time, induction therapy is commonly used in upwards of 80%, of renal transplant recipients. Depleting agents are the most frequently used agents and they account for more than 75% of all induction therapies in the United States. Currently, there is no consensus regarding the choice of induction therapy. The type of induction therapy is generally selected based on a comprehensive evaluation of the recipient and the donor's immunological risks, the risk of developing opportunistic infection and malignancy, recipient comorbidities, financial burden and the choice of maintenance immunosuppressive regimen.

Long-term outcomes following sirolimus conversion after renal transplantation.

Long-term outcomes following renal transplantation remain limited due to chronic progressive injury partly as a result of calcineurin inhibitor (CNI) toxicity. Thus, patients have been converted to non-CNI immunosuppressives despite the lack of evidence of long-term benefits from CNI free therapy. We now report our 10-year experience converting patients with well functioning transplants from CNI to sirolimus. We retrospectively analyzed outcomes of patients receiving continuous CNI based therapy (CNI, n = 309) or who were switched to sirolimus within the first year of post-transplantation (CONV, n = 54). The groups were similar for most recipient, graft and donor characteristics, however, diabetes was more common in the CNI group and statin use was more frequent in the CONV group. The average time to conversion was 7.2 months and the creatinine level at the time of switching was 1.4 mg/dl. Ten year graft and patient survival rates were equivalent in both groups. There were no differences in the causes of death or graft loss in both groups. Renal function was available for 5 years posttransplant and was no different between groups. Thus, there is no evidence that routinely switching patients with well functioning renal allografts to sirolimus from CNI based immunosuppression provides long-term benefit.

Long-term dosing patterns of enteric-coated mycophenolate sodium or mycophenolate mofetil with tacrolimus after renal transplantation.

MORE was a four-yr, prospective, observational study at 40 transplant centers in the US. Data were analyzed to evaluate changes in mycophenolic acid (MPA) dosing over time in 904 de novo kidney transplant recipients receiving enteric-coated mycophenolate sodium (EC-MPS, n = 616) or mycophenolate mofetil (MMF, n = 288) with tacrolimus. Induction therapy and steroid treatment were similar in the two subpopulations. The proportion of patients receiving the maximal recommended MPA dose was 80.5%, 43.9%, 39.2%, 34.6%, and 30.1% at baseline and years 1, 2, 3, and 4, respectively. More patients received the maximal recommended MPA dose with EC-MPS vs. MMF at month 1 (79.2% vs. 71.7%, p = 0.016), month 3 (68.5% vs. 56.9%, p = 0.001), and month 6 (52.9% vs. 44.0%, p = 0.028). Multivariate analysis showed the risk of biopsy-proven acute rejection, graft loss or death to be similar for EC-MPS vs. MMF. Estimated glomerular filtration rate (GFR) was similar with EC-MPS vs. MMF at all time points. There were no significant differences in any category of adverse event between the EC-MPS and MMF cohorts during follow-up, including gastrointestinal events. In conclusion, MPA dose was maintained more effectively in the first six months after kidney transplantation using EC-MPS vs. MMF, without an increase in adverse events.

Long-term outcomes in African American kidney transplant recipients under contemporary immunosuppression: a four-yr analysis of the Mycophenolic acid Observational REnal transplant (MORE) study.

Mycophenolic acid Observational REnal transplant (MORE) was a prospective, observational study of de novo kidney transplant patients receiving mycophenolic acid (MPA). Four-yr data on 904 patients receiving tacrolimus and enteric-coated mycophenolate sodium (EC-MPS) or mycophenolate mofetil (MMF) were analyzed to evaluate immunosuppression and graft outcomes in African American (AA, n = 218) vs. non-AA (n = 686) patients. Mean tacrolimus dose was higher in AA vs. non-AA patients but mean tacrolimus trough concentration was similar. Use of the recommended MPA dose in AA patients decreased from 78.9% at baseline to 33.1% at year 3. More AA patients received the recommended MPA dose with EC-MPS than MMF at month 6 (56.2% vs. 35.7%, p = 0.016) and month 36 (46.6% vs. 16.7%, p = 0.029), with no safety penalty. Significantly, more AA patients received corticosteroids than non-AA patients. Biopsy-proven acute rejection was higher in AA vs. non-AA patients (18.9% vs. 10.7%, p = 0.003), as was graft loss (10.9% vs. 4.4%, p = 0.003); differences were confirmed by Cox regression analysis. Patient survival was similar. Estimated GFR was comparable in AA vs. non-AA patients. Kidney allograft survival remains lower for AA vs. non-AA recipients even under the current standard of care.

Temporal histological changes in lacrimal and major salivary glands in mouse models of Sjogren's syndrome.

BACKGROUND: Evidence in imaging studies suggests that there may be differences in glandular involvement in Sjogren's syndrome (SS) depending on the stage of the disease. No detailed histological studies are available to show if there are any such difference in glandular involvement at various time periods and stages of SS. This cross sectional study examines the inflammatory changes in mouse models of SS at various ages. METHODS: The histological changes in major salivary and lacrimal glands were studied at ages of 3, 6, 9, 12, 15 and 18 months in both sexes in well characterized mouse models of SS, non-obese diabetes mouse and Interleukin-14 alpha-transgenic mice. RESULTS: Our results indicate that early inflammation concurrently occur in submandibular and lacrimal glands around the age of 6 weeks. Parotid glands are involved much later in the course of SS with less severe inflammation. Sublingual glands are rarely involved. CONCLUSIONS: Our conclusions are that SS may be an organ specific disease with early inflammation occurring in submandibular and lacrimal glands, followed by the parotid. Non organ specific events occur in later courses of the disease. The understanding of the disease progression is important in tailoring early local therapeutic interventions before complete destruction of salivary and lacrimal glands.

Outcomes in African American kidney transplant patients receiving tacrolimus and mycophenolic acid immunosuppression.

BACKGROUND: Prospective data regarding immunosuppression and rejection in African American patients receiving modern immunosuppressive regimens are sparse. METHODS: One-year data were analyzed from 901 tacrolimus-treated de novo kidney transplant patients in the prospective Mycophenolic Acid Observational Renal Transplant registry. RESULTS: Mean tacrolimus dose was significantly higher in African Americans (n=217) versus non-African Americans (n=684), but mean tacrolimus trough concentrations were similar. The proportion of patients receiving mycophenolic acid dose equal to or more than 2000 mg per day (mycophenolate mofetil equivalents) was significantly higher with enteric-coated mycophenolate sodium versus mycophenolate mofetil at month 6 among African Americans and at month 3 in non-African Americans, but rates of acute rejection and adverse events (including gastrointestinal events) were similar. The 1-year incidence of biopsy-proven acute rejection (BPAR) was 14.1% in African Americans versus 7.5% in non-African Americans. On multivariate analysis, African American ethnicity was associated with a higher risk of BPAR (hazard ratio, 1.93; 95% confidence interval, 1.19-3.09; P=0.007). Mean (standard deviation) glomerular filtration rate at month 12 estimated by the Chronic Kidney Disease Epidemiology Collaboration formula was 59.2 (22.2) mL/min/1.73 m in African Americans versus 58.8 (19.9) mL/min/1.73 m in non-African Americans (confidence interval of the difference, -3.4 to 4.3; P=0.83). CONCLUSION: This observational study confirms that African Americans require higher doses of tacrolimus to achieve target trough concentrations and are more likely to experience BPAR during the first year after kidney transplantation despite modern immunosuppression regimens. In our 1-year study, this was not associated with significantly inferior graft survival.

Does reduction in mycophenolic acid dose compromise efficacy regardless of tacrolimus exposure level? An analysis of prospective data from the Mycophenolic Renal Transplant (MORE) Registry.

Prospective data are lacking concerning the effect of reduced mycophenolic acid (MPA) dosing on efficacy and the influence of concomitant tacrolimus exposure. The Mycophenolic Renal Transplant (MORE) Registry is a prospective, observational study of de novo kidney transplant patients receiving MPA therapy under routine management. The effect of MPA dose reduction, interruption, or discontinuation (dose changes) was assessed in 870 tacrolimus-treated patients: 375 (43.1%) reduced tacrolimus (≤ 7 ng/mL at baseline) and 495 (56.9%) standard tacrolimus (>7 ng/mL); enteric-coated mycophenolate sodium 589 (67.7%) and mycophenolate mofetil 281 (32.3%). During baseline to month 1, months 1-3, months 3-6, and months 6-12, 9.3% (78/838), 16.6% (132/794), 20.7% (145/701), and 13.1% (70/535) patients, respectively, required MPA dose changes. These patients experienced an increased risk of biopsy-proven acute rejection at one yr with tacrolimus exposure either included in the model (hazard ratio [HR] 2.60, 95% CI 1.28-5.29, p = 0.008) or excluded (HR 2.58, 95% CI 1.28-5.23, p = 0.008). MPA dose changes were significantly associated with one yr graft failure when tacrolimus exposure was included (HR 2.23; 95% CI 1.01-4.89, p = 0.047) but not when tacrolimus exposure was excluded (HR 2.16; 95% CI 0.99-4.79; p = 0.054). These results suggest that reducing or discontinuing MPA can adversely affect graft outcomes regardless of tacrolimus trough levels.

Inhibiting Wipf2 downregulation by transgenic expression of its 3' mRNA-untranslated region improves cytotoxicity and vaccination response.

Lymphocyte activation results in profound changes in the abundance of mRNA transcripts many of which are downregulated. The Wiskott-Aldrich syndrome (WAS) protein (WASP) family is critical for productive T-cell receptor signaling and actin reorganization. The WASP signal pathway includes the WAS/WAS-like (WASL) interacting protein family 2 (WIPF2) gene also known as WIRE/WICH. We show that both human WIPF2 and mouse Wipf2 are mice, alternatively spliced within the 3' untranslated region (3'UTR) resulting in two major transcripts of approximately 4.5 and 6 kb in size. Following T-cell activation, the level of human WIPF2 and mouse Wipf2 mRNA rapidly declines. In mice, this decline is accompanied by a marked reduction in WIPF2 protein levels. Transgenic expression of a 240-bp fragment derived from a highly conserved terminal 3'UTR found within the 6-kb transcript blocks Wipf2 downregulation. These effects may be mediated by competitive inhibition of microinhibitory RNA (miRNA) regulation since the 6-kb-derived transgene and the 4.5-kb transcript share functional binding sites for miRNA146a. Blocking Wipf2 gene and protein repression resulted in improved T-cell responses to antigen immunization in vivo as well as in vitro cytotoxic T-cell killing. Collectively, these data suggest that early downregulation of this immunologically relevant gene controls the intensity of selective lymphocyte functions.

Universal perioperative antimicrobial prophylaxis is not necessary in kidney transplantation.

Despite significant improvements in renal transplantation, certain basic issues remain unresolved such as the routine use of perioperative antimicrobial prophylaxis (AMP). To address the need for AMP, we retrospectively evaluated the clinical course of 442 consecutive renal transplant recipients (RTRs) who did not receive any AMP except for trimethoprim/sulfamethoxazole. Three hundred and forty RTRs received induction therapy with low-dose rabbit anti-thymocyte globulin, while the other 102 patients were treated with basiliximab. All RTRs received tacrolimus, mycophenolic acid, and prednisone. Nine patients (2%) developed surgical site infection (SSI). SSIs were more common in obese and older patients. All SSIs were superficial and responded well to wound drainage and outpatient antibiotic therapy. No patient or graft was lost owing to SSI. Our study shows that despite many predisposing factors, SSIs are rare following renal transplantation even in the absence of AMP. Therefore, to avoid the emergence of antibiotic-resistant pathogens, excessive costs, and antibiotic-related adverse events, we suggest that AMP should be used only in selected circumstances such as in recipients older than 65 yr or when the body mass index (BMI) is > 35.

A role for lymphotoxin in primary Sjogren's disease.

The etiology of salivary gland injury in primary Sjögren's disease is not well understood. We have previously described a mouse model of Sjögren's disease, IL-14α transgenic (IL14αTG) mice, which reproduces many of the features of the human disease. We now demonstrate a critical role for lymphotoxin α (LTA) in the pathogenesis of Sjögren's disease in IL14αTG mice. IL14αTG mice express LTA mRNA in their salivary glands and spleen and produce soluble LTA protein in their salivary secretions. When IL14αTG mice were crossed with LTA(-/-) mice, the IL14αTG.LTA(-/-) mice retained normal salivary gland secretions and did not develop either lymphocytic infiltration of their salivary glands or secondary lymphomas. However, both IL14αTG and IL14αTG.LTA(-/-) mice produced similar amounts of IFN-α and had similar deposition of autoantibodies in their salivary glands. Both IL14α and IL14α/LTA(-/-) mice had similar B cell responses to T-dependent and T-independent Ags, L-selectin expression, and expression of RelA, RelB, and NF-κB2 in their spleens. These studies suggest that LTA plays a critical role in the local rather than systemic inflammatory process of Sjögren's disease. Furthermore, local production of soluble LTA in the salivary glands of IL14αTG mice is necessary for the development of overt Sjögren's disease. Autoantibody deposition alone is not sufficient to produce salivary gland dysfunction. We also demonstrate that LTA is increased in the salivary gland secretions and sera of patients with Sjögren's disease, further strengthening the biological relevance of the IL14αTG model to understanding the pathogenesis of human disease.

Low levels of high-density lipoprotein cholesterol: an independent risk factor for late adverse cardiovascular events in renal transplant recipients.

Long-term kidney transplant graft and patient survival is often limited by cardiovascular (CV) disease. Risk factors for CV disease such as diabetes, hypertension and elevated low-density lipoprotein levels are well documented; however, the impact of low levels of high-density lipoprotein (HDL) has not been defined. We performed a retrospective chart review of 324 consecutive renal transplant recipients from 2001 to 2007 to correlate baseline HDL levels with major adverse cardiovascular events (MACEs) defined as a composite of new onset CV illness, cerebral vascular events and peripheral vascular disease. A total of 92 MACEs occurred over a total of 1913 patient years of follow-up. Low HDL cholesterol levels were noted in 58.3% of patients. Compared with those with normal HDL levels, a greater percentage of patients with low HDL levels had post-transplant MACEs (20% vs. 60% respectively) and experienced an increased rate of all cause mortality. Sixty-two percent of all MACEs occurred in patients with low HDL levels. In the low HDL group, the odds ratio for experiencing a MACE was 1.92. Therefore, HDL cholesterol may provide an important new therapeutic target to prevent vascular morbidity and mortality following renal transplantation.

A nonsimultaneous, extended, altruistic-donor chain.

We report a chain of 10 kidney transplantations, initiated in July 2007 by a single altruistic donor (i.e., a donor without a designated recipient) and coordinated over a period of 8 months by two large paired-donation registries. These transplantations involved six transplantation centers in five states. In the case of five of the transplantations, the donors and their coregistered recipients underwent surgery simultaneously. In the other five cases, "bridge donors" continued the chain as many as 5 months after the coregistered recipients in their own pairs had received transplants. This report of a chain of paired kidney donations, in which the transplantations were not necessarily performed simultaneously, illustrates the potential of this strategy.

IL-14 alpha, the nexus for primary Sjögren's disease in mice and humans.

To evaluate the role of interleukin 14 alpha (IL-14a) in Sjögren's syndrome (SS), we evaluated the expression of IL-14a in the peripheral blood lymphocytes (PBL) of patients with primary and secondary SS and normal controls by quantitative RT-PCR. In addition, transgenic IL-14a mice were analyzed from 6 weeks of age to death for both histological and immunological features of Sjögren's disease. Patients with both primary and secondary Sjögren's syndrome expressed IL-14a at statistically higher levels in their peripheral blood compared to normal controls matched for age, sex and ethnic group. Transgenic mice in which IL-14a expression was increased constitutively were previously demonstrated to develop hypergammaglobulinemia, autoantibodies, infiltration of the parotid glands with lymphocytes, mild immune-complex mediated renal disease and large B cell lymphoma. In this paper we expand these observations to demonstrate that these mice develop all the clinical and immunological features of primary Sjögren's disease in the same relative time frame as patients with primary Sjögren's disease: stage 1-early hypergammaglobulinemia and autoantibody production, stage 2-decreased salivary gland function with early lymphocytic infiltration of the submandibular glands only, but antibody deposition in the submandibular and parotid glands, stage 3-lymphocytic infiltration of the submandibular, parotid and lacrimal glands with B and T lymphocytes and plasma cells along with interstitial lung disease and mild renal disease, and stage 4-large B cell lymphoma. Thus IL-14a is important in the pathophysiology of Sjögren's disease. The IL-14a transgenic mouse is a novel animal model that can be utilized to understand the pathophysiology of Sjögren's disease.

Regulation of human interleukin 14 transcription in vitro and in vivo after renal transplantation.

BACKGROUND: Alloantibodies and B lymphocytes are felt to contribute in increasingly important ways to the pathogenesis of both acute and chronic allograft injury. The mechanisms that lead to the formation of posttransplant alloantibodies despite immunosuppressive therapy have not been fully elucidated. Interleukin 14 (IL-14) or high molecular weight B cell growth factor secreted by activated T and B cells and follicular dendritic cells promotes B cell growth, survival and memory, and antibody production. The potential role of IL-14 in human transplantation has not been examined. METHODS: Using quantitative polymerase chain reaction techniques, we examined IL-14 mRNA transcript levels in human cells and compared them to IL-2. Interleukin-14 mRNA levels were measured in isolated human T cells stimulated in vitro with mitogen and alloantigen in the presence or absence of immunosuppressive drugs. In vivo, IL-14 transcript levels were measured in peripheral blood leukocytes isolated from patients after renal transplantation. RESULTS: In vitro, both IL-14 and IL-2 transcript levels increase after alloantigen and mitogen stimulation and are suppressed by currently used immunosuppressive agents. In vivo, IL-14 and IL-2 behave differently as IL-14 transcript levels are not reduced by immunosuppressive therapy. Interleukin-14 transcripts also increase after both immune and nonimmune injury to renal allografts. CONCLUSIONS: This is the first demonstration of human IL-14 mRNA regulation in vitro and in vivo. Given the important effects of IL-14 on B cell proliferation and antibody production, increases in IL-14 transcript levels may play a role in alloantibody formation after renal transplantation.

Randomized prospective trial of early steroid withdrawal compared with low-dose steroids in renal transplant recipients using serial protocol biopsies to assess efficacy and safety.

BACKGROUND: Corticosteroid therapy after renal transplantation is associated with many adverse effects. Newer immunosuppressive agents may allow for safe and effective reductions in dose or early steroid withdrawal. METHODS: In this prospective, single-center clinical trial, 60 patients were randomized into 2 groups: control patients (n = 28), who received low doses of prednisone throughout, and study patients (n = 32), who were withdrawn from steroids 7 days posttransplant. Patients received a limited course of rabbit antilymphocyte globulin (rALG) induction therapy, tacrolimus (TAC), and mycophenolate mofetil (MMF). Patients were followed for clinical outcomes and renal function. Protocol biopsies were performed at 1, 6, and 12 months. RESULTS: Clinical rejections occurred in 11% of controls and 13% of study patients. Renal function was well maintained and equivalent in both groups. In all, 111 protocol biopsies were performed without complications. Subclinical rejection was noted in only 2 protocol biopsies, and borderline changes were seen in 12 biopsies, all of which were distributed equally between both groups. Unsuspected acute TAC toxicity was seen in 8 biopsies. Protocol biopsies led to changes in therapy in 10% of patients. In both groups, serial protocol biopsies demonstrated increased allograft fibrosis over time, which was significant at 1 year in the steroid withdrawal group. CONCLUSION: The immunosuppressive combination of rALG, TAC, and MMF prevents subclinical rejection and the need for high doses of steroids after transplantation. However, continual low-dose steroid therapy may aid in preventing chronic allograft fibrosis. Protocol biopsies help define the short-term and long-term risks of steroid withdrawal therapy.