Immunologic risk stratification of pediatric heart transplant patients by combining HLAMatchmaker and PIRCHE-II.

BACKGROUND: Molecular-level human leukocyte antigen (HLA) mismatch is a powerful biomarker of rejection; however, few studies have explored its use in heart transplant recipients, and none have attempted to use the results of separate algorithms synergistically. Here we tested the hypothesis that a combination of HLAMatchmaker and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II) can be used to identify more patients at low risk of rejection. METHODS: We studied 274 recipient/donor pairs enrolled in the Clinical Trials in Organ Transplantation in Children (CTOTC) performing class I and II HLA genotyping by next-generation sequencing to determine eplet mismatch (epMM) load and PIRCHE-II score. Correlation with clinical outcomes was performed on 131 cases. RESULTS: Of the 131 patients, 100 without pre-formed donor specific antibody (DSA) were used to identify cutoffs for the Class I, HLA-DR, and HLA-DQ epMM load and PIRCHE-II score for risk of developing post-transplant DSA (epMM: Class I/DR/DQ = 9/9/6; PIRCHE-II: 141/116/111) and antibody-mediated rejection (ABMR) (epMM: 9/8/8; PIRCHE-II: 157/80/201). Patients with above cut-off epMM load appear to be less likely to develop DSA and ABMR if their PIRCHE-II score is below cut-off (high epMM/high PIRCHE-II: 12.3%-20.3% DSA and 9%-13.5% ABMR vs high epMM/low PIRCHE-II: 4%-10% DSA and 0%-2% ABMR). CONCLUSION: For the first time in a pediatric heart transplant cohort, immunologic risk cut-offs for DSA and ABMR have been established. When used together, epMM load and PIRCHE-II score allow us to reclassify a portion of cases with high epMM load as having a lower risk for developing DSA and ABMR.

A phase 2 randomized, double-masked, placebo-controlled study of novel nonsystemic kinase inhibitor TOP1630 for the treatment of dry eye disease.

PURPOSE: To evaluate the safety and efficacy of topical TOP1630, a novel nonsystemic kinase inhibitor, in dry eye disease (DED). PATIENTS AND METHODS: A randomized, double-masked, parallel-group trial of 0.1% TOP1630 ophthalmic solution TID or placebo (vehicle without active drug) was conducted in DED subjects (n=61). Key eligibility criteria consistent with enrolling a moderate to severe DED population included >6 months DED history; OSDI© score ≥18; Schirmer's test score ≤10 and ≥1 mm/5 minutes; tear film break-up time >1 and <7 seconds; and dry eye exacerbation in corneal staining and ocular discomfort in a Controlled Adverse Environment (CAE®). After a 7-day run-in period with placebo TID, eligible subjects were randomized to TOP1630 or placebo for 28 days. No supplemental artificial tears or rescue medication were allowed. RESULTS: TOP1630 was safe, well-tolerated, and efficacious in treating DED symptoms and signs. No serious adverse events (AEs) or withdrawals due to treatment emergent AEs occurred. Drop comfort scores showed TOP1630 to be comfortable and comparable with placebo. Significant symptom improvements were seen for TOP1630 vs placebo for ocular discomfort (P=0.02 post-CAE), grittiness/foreign body sensation (on four independent assessment scales, each P<0.05), worst DED symptom (diary, P=0.06), and ocular pain (VAS, P=0.03). Sign improvements were seen for total ocular surface (all regions), corneal sum, and conjunctival sum staining with TOP1630 compared with placebo (each P<0.05). CONCLUSION: TOP1630 had placebo-like tolerability and produced improvements in multiple symptom and sign endpoints in both environmental and challenge settings. The emergent TOP1630 benefit-risk profile for DED treatment is highly favorable and supports further development.

Narrow Spectrum Kinase Inhibitors Demonstrate Promise for the Treatment of Dry Eye Disease and Other Ocular Inflammatory Disorders.

Purpose: The purpose of this study is to determine the potential of narrow spectrum kinase inhibitors (NSKIs) to treat inflammatory eye disorders. Methods: Human conjunctival epithelial (HCE) cells were retrieved from subjects via impression cytology. Real-time quantitative PCR (qPCR) was performed on HCE cells to determine gene expression of NSKI kinase targets and proinflammatory cytokines in dry eye disease (DED) patients versus healthy controls. qPCR also assessed p38α expression in hyperosmolar-treated Chang conjunctival epithelial cells. Interaction of NSKI TOP1362 with the kinases was evaluated in ATP-dependent Z-LYTE and competition binding assays. Anti-inflammatory activity was assessed in human peripheral blood mononuclear cells and primary macrophages. In an endotoxin-induced uveitis (EIU) study, lipopolysaccharide (LPS) was administered intravitreally to Lewis rats. TOP1362, dexamethasone, or vehicle was administered topically, and inflammatory cytokine levels were measured 6 hours after LPS injection. Results: HCE cells from DED patients showed significantly increased expression of p38α, spleen tyrosine kinase (Syk), Src, lymphocyte-specific protein tyrosine kinase (Lck), interleukin one beta (IL-1ß), interleukin eight (IL-8), monocyte chemotactic protein-1 (MCP-1), and matrix metalloproteinase-9 (MMP-9). TOP1362 strongly inhibited the kinase targets p38α, Syk, Src, and Lck, blocked the rise in p38α expression in hyperosmolar Chang cells, and potently reduced inflammatory cytokine release in cellular models of innate and adaptive immunities. In the EIU model, TOP1362 dose-dependently attenuated the LPS-induced rise in inflammatory cell infiltration and ocular cytokine levels with efficacy comparable to that of dexamethasone. Conclusions: TOP1362 is a potent inhibitor of kinases upregulated in DED and markedly attenuates proinflammatory cytokine release in vitro and in vivo, highlighting the therapeutic potential of NSKIs for treating ocular inflammation, such as that observed in DED.

Effect of Narrow Spectrum Versus Selective Kinase Inhibitors on the Intestinal Proinflammatory Immune Response in Ulcerative Colitis.

BACKGROUND: Kinases are key mediators of inflammation, highlighting the potential of kinase inhibitors as treatments for inflammatory disorders. Selective kinase inhibitors, however, have proved disappointing, particularly in the treatment of rheumatoid arthritis and inflammatory bowel disease. Consequently, to improve efficacy, attention has turned to multikinase inhibition. METHODS: The activity of a narrow spectrum kinase inhibitor, TOP1210, has been compared with selective kinase inhibitors (BIRB-796, dasatinib and BAY-61-3606) in a range of kinase assays, inflammatory cell assays, and in inflamed biopsies from patients with ulcerative colitis (UC). Effects on recombinant P38α, Src, and Syk kinase activities were assessed using Z-lyte assays (Invitrogen, Paisley, United Kingdom). Anti-inflammatory effects were assessed by measurement of proinflammatory cytokine release from peripheral blood mononuclear cells, primary macrophages, HT29 cells, inflamed colonic UC biopsies, and myofibroblasts isolated from inflamed colonic UC mucosa. RESULTS: TOP1210 potently inhibits P38α, Src, and Syk kinase activities. Similarly, TOP1210 demonstrates potent inhibitory activity against proinflammatory cytokine release in each of the cellular assays and the inflamed colonic UC biopsies and myofibroblasts isolated from inflamed colonic UC mucosa. Generally, the selective kinase inhibitors showed limited and weaker activity in the cellular assays compared with the broad inhibitory profile of TOP1210. However, combination of the selective inhibitors led to improved efficacy and potency in both cellular and UC biopsy assays. CONCLUSIONS: Targeted, multikinase inhibition with TOP1210 leads to a broad efficacy profile in both the innate and adaptive immune responses, with significant advantages over existing selective kinase approaches, and potentially offers a much improved therapeutic benefit in inflammatory bowel disease.

Lobar displacement following pediatric heart-lung transplantation: case report and review of literature.

Lobar displacement (LD) after heart-lung transplantation (HLT) has been reported in adults, but there are no reported pediatric cases. Its occurrence may cause vascular compromise of the displaced lung segment leading to necrosis, infection and bronchiectasis, as well as compression of contralateral lobes. We report two cases of LD in children following HLT, treated differently and with different outcomes. Assessment of pulmonary perfusion and weighing the risk of surgical repair may be considered for optimal patient management of this condition.

Post-transplant Burkitt lymphoma is a more aggressive and distinct form of post-transplant lymphoproliferative disorder.

BACKGROUND: Although the literature reports a low incidence of Burkitt lymphoma (BL) as a post-transplant lymphoproliferative disorder (PTLD), this entity appears to be different from other monomorphic PTLDs (M-PTLDs), both in its aggressive clinical presentation and its distinct pathologic profile. METHODS: Patients with BL, diagnosed in the post-transplant setting, (patients aged ≤ 18 years) were retrieved from the pathology archives at Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center from 1982 to 2010. Clinical outcomes were obtained along with pathologic review. RESULTS: Twelve patients with pediatric BL in the post-transplant setting (9 boys, 3 girls) were retrieved. The patients displayed a monomorphic population of small to intermediate-sized, noncleaved, lymphoid elements with a "starry-sky" pattern. The immunophenotype for patients available to the study was CD20+ (n = 9/10), CD10+ (n = 8/8), bcl-6+ (n = 11/11), with a near 100% Ki-67/MIB-1 proliferation index (n = 7/7), and negative for TdT (n = 7/7). Most pretransplant Epstein-Barr virus titers were negative (n = 8/10), with post-transplant titers positive in all tested patients (n = 11), and with positive Epstein-Barr-encoded RNA in situ hybridization in most cases (n = 9/11). The median time from transplantation to diagnosis was 52 months (range, 6-107 months). Nine patients were currently alive after immediate antineoplastic chemotherapy, with median disease-free time of 93 months from diagnosis (range, 2-199 months). CONCLUSIONS: BL-PTLD had a higher Epstein-Barr virus incidence compared with sporadic and immunodeficiency-associated BL and represented a distinct monomorphic PTLD. Although some M-PTLDs can be managed less aggressively with decreased immunosuppression alone, immediate lymphoma-specific chemotherapy was associated with a favorable outcome and was strongly recommended.

The impact of EBV load on T-cell immunity in pediatric thoracic transplant recipients.

BACKGROUND: Immunologic monitoring of pediatric transplant (Tx) recipients, who are at increased risk of Epstein-Barr virus (EBV)-driven posttransplant lymphoproliferative disease, is an important goal in clinical transplantation. Here, we investigated the impact of EBV load on T-cell immunity from pediatric Tx recipients, using clinically applicable tests for improved assessment of T-cell immune competence. METHODS: Thirty-five asymptomatic pediatric thoracic Tx patients were categorized into three groups according to their EBV load levels as follows: undetectable viral load (UVL), chronic low viral load (LVL) and chronic high viral load (HVL). Global and EBV-specific T-cell immunity were assessed by ATP release using Cylex Immuknow and T Cell Memory assays. RESULTS: UVL patients exhibited normal ATP release to Concanavalin A (ConA) and phytohemagglutinin (PHA; 190+/-86 ng/mL, 328+/-163 ng/mL) and detectable EBV-specific (37+/-34 ng/mL) ATP responses. LVL patients displayed significantly stronger responses to ConA (373+/-174 ng/mL), PHA (498+/-196 ng/mL) and EBV (152+/-179 ng/mL), when compared with UVL or to HVL patients (ConA 185+/-114 ng/mL, PHA 318+/-173 ng/mL, and EBV 33+/-42 ng/mL). Moreover, HVL patients displayed significant inverse correlation between CD4+ T-cell ATP levels and EBV loads. CONCLUSIONS: Evaluation of global and EBV-specific T-cell immunity provides a rapid assessment of patients' immune competence. It is still unclear whether selective oversuppressed ATP release by CD4+ T cells reflects HVL patients at risk of posttransplant lymphoproliferative disease. Further longitudinal studies will determine the importance of Immuknow test in identifying asymptomatic HVL patients vulnerable to EBV complications.

A novel variant L263F in human inosine 5'-monophosphate dehydrogenase 2 is associated with diminished enzyme activity.

BACKGROUND AND OBJECTIVE: Inosine 5'-monophosphate dehydrogenase 2 is required for purine synthesis in activated lymphocytes. Variants in the IMPDH2 gene may account for the large inter-individual variability in baseline enzyme activity, immunosuppressive efficacy and side effects in transplant recipients receiving mycophenolic acid. Therefore, the objective of this study was to identify and functionally characterize IMPDH2 variants. METHODS: DNA samples from 152 solid organ transplant patients were screened at exons and exon/intron junctions of the IMPDH2 genes by PCR amplification followed by bidirectional direct DNA sequencing. Genetic variant was constructed by site-directed mutagenesis and transformed to an inosine 5'-monophosphate dehydrogenase-deficient strain of Escherichia coli h712. Proteins were purified to homogeneity and the enzymatic activity was measured by reduced nicotinamide adenine dinucleotide production. RESULTS: Nine genetic variants were identified in the IMPDH2 gene, with frequencies of the rarer alleles ranging from 0.5 to 10.2%. A novel nonsynonymous variant L263F was identified, and the kinetic assay demonstrated that the inosine 5'-monophosphate dehydrogenase activity of L263F variant was decreased to 10% of the wild-type. The Ki for mycophenolic acid inhibition of the L263F variant was comparable with the wild-type, and the variant Km for inosine 5'-monophosphate and nicotinamide adenine dinucleotide did not change significantly. CONCLUSIONS: IMPDH2 has low genetic diversity, but the nonsynonymous variant L263F has a significant impact on inosine 5'-monophosphate dehydrogenase activity. This novel functional variant may be one of the factors contributing to the inter-individual difference of baseline inosine 5'-monophosphate dehydrogenase activity as well as drug efficacy and adverse events in transplant patients.

Cardiac re-transplantation in pediatrics: a multi-institutional study.

BACKGROUND: Cardiac re-transplantation (re-Tx) among pediatric recipients remains controversial. The purpose of this study is to use the Pediatric Heart Transplant Study (PHTS) database to investigate the incidence of re-Tx and analyze the risk factors and outcomes after transplantation among children. METHODS: The PHTS database was reviewed for all subjects or=1 year after their PTx, especially those with graft coronary artery disease.

Pediatric heart transplantation for anthracycline cardiomyopathy: cancer recurrence is rare.

BACKGROUND: Although anthracycline therapy is invaluable for treating neoplastic disorders, morbidity includes severe cardiomyopathy that leads to heart transplantation. This multicenter study describes the course of children who experienced anthracycline cardiomyopathy (ACM) and who subsequently required heart transplantation. METHODS: We reviewed transplant databases/registries at 4 pediatric heart transplant centers to identify children with ACM who were listed for heart transplantation. We reviewed medical records to determine cancer therapy, clinical course, and outcome. RESULTS: Eighteen patients were listed, and 17 underwent transplantation. Mean age at cancer diagnosis was 6.0 years (SD, 3.7). The mean anthracycline dose was 361 mg/m2 (SD, 110). The median time from cancer diagnosis to listing for heart transplantation was 9.2 years (range, 0.4-15.2 years). Six transplantations were performed in patients who had disease-free intervals of <5 years. Two patients were lost to follow-up, and 8 are alive at 4.9 years (SD, 2.0; range, 1.3-7.4 years) after transplantation. Seven patients died at 4.7 years (SD, 2.0; range, 1.2-7.1 years) after transplantation. One patient had recurrent cancer. One-, 2- and 5-year survivals were 100%, 92%, and 60%, respectively. CONCLUSIONS: Cardiomyopathy that progresses to the need for heart transplantation occurs in patients receiving a wide range of cumulative anthracycline doses. The time from chemotherapy to ACM varies. Outcomes after transplantation are acceptable, and cancer recurrence is rare. Reconsideration of the 5-year disease-free wait period is warranted.

Pharmacokinetics of sirolimus and tacrolimus in pediatric transplant patients.

To evaluate the pharmacokinetics of Sirolimus (SRL) and Tacrolimus (TAC) in pediatric transplant recipients. Fifty-one SRL and 55 TAC pharmacokinetic profiles were obtained from 20 male and 14 female recipients of liver alone (LTx, n = 23), small bowel alone, and with liver (SBTx, n = 11). The median age was 13.3 years (range 0.9-23.9). Whole blood concentrations of SRL and TAC were determined by liquid chromatography-mass spectrometry (LC-MS) and microparticulate enzyme immunoassay (MEIA-Abbott Laboratories, IL), respectively. Pharmacokinetic (PK) parameters were derived from noncompartmental model analysis. The half-life was estimated using the data points during the terminal disposition phase and area under the concentration (AUC) time curve was calculated within a dosing interval using the trapezoidal method. The dose of SRL or TAC did not correlate with the corresponding AUCs. Trough concentrations of SRL and TAC correlated well with AUC (r = 0.8544 and 0.8603, respectively). Half-life (h) did not differ significantly between different transplant groups for SRL and TAC (SRL: LTx: 21.2 h, SBTx: 19.3 h; TAC: LTx: 14.1 h, SBTx: 12.7 h). Serial PK analysis with the first measurement within 14 days after transplantation revealed no difference in AUC/dose/BSA for SRL, with time. During this period, SRL half-life increased significantly, from 11.2 +/- 1.0-20.1 +/- 3.1 h (n = 4; p = 0.02). After introduction of SRL, TAC half-life did not change (11.6 +/- 3.9-14.0 +/- 10.4, n = 10, P = 0.52) in all the groups analyzed together. TAC AUC/dose/BSA decreased significantly in LTx and SBTx patients (90.9 +/- 55.3 vs. 48.8 +/- 27.3). Trough concentration measurements provide good estimates of SRL and TAC exposure in pediatric transplant recipients. The short half-life of SRL in children may support twice-daily administration early after liver and small intestinal transplantation. During conversion of subjects from TAC to combined TAC and SRL, aggressive therapeutic drug monitoring must be used to individualize therapy and avoid serous adverse events.

Differential effects of ebselen on neutrophil recruitment, chemokine, and inflammatory mediator expression in a rat model of lipopolysaccharide-induced pulmonary inflammation.

We postulated that the seleno-organic compound ebselen would attenuate neutrophil recruitment and activation after aerosolized challenge with endotoxin (LPS) through its effect as an antioxidant and inhibitor of gene activation. Rats were given ebselen (1-100 mg/kg i.p.) followed by aerosolized LPS exposure (0.3 mg/ml for 30 min). Airway inflammatory indices were measured 4 h postchallenge. Bronchoalveolar lavage (BAL) fluid cellularity and myeloperoxidase activity were used as a measure of neutrophil recruitment and activation. RT-PCR analysis was performed in lung tissue to assess gene expression of TNF-alpha, cytokine-induced neutrophil chemoattractant-1 (CINC-1), macrophage-inflammatory protein-2 (MIP-2), ICAM-1, IL-10, and inducible NO synthase. Protein levels in lung and BAL were also determined by ELISA. Ebselen pretreatment inhibited neutrophil influx and activation as assessed by BAL fluid cellularity and myeloperoxidase activity in cell-free BAL and BAL cell homogenates. This protective effect was accompanied by a significant reduction in lung and BAL fluid TNF-alpha and IL-1 beta protein and/or mRNA levels. Ebselen pretreatment also prevented lung ICAM-1 mRNA up-regulation in response to airway challenge with LPS. This was not a global effect of ebselen on LPS-induced gene expression, because the rise in lung and BAL CINC-1 and MIP-2 protein levels were unaffected as were lung mRNA expressions for CINC-1, MIP-2, IL-10, and inducible NO synthase. These data suggest that the anti-inflammatory properties of ebselen are achieved through an inhibition of lung ICAM-1 expression possibly through an inhibition of TNF-alpha and IL-1 beta, which are potent neutrophil recruiting mediators and effective inducers of ICAM-1 expression.

Cytokine gene polymorphisms in children successfully withdrawn from immunosuppression after liver transplantation.

BACKGROUND: Cytokine genetic polymorphisms have been associated with transplant outcome in some experimental and clinical studies, but the cytokine profile of patients who are clinically tolerant has not been investigated. AIM: Allelic variations in tumor necrosis factor (TNF)-alpha, interferon (INF)-gamma, transforming growth factor (TGF)-beta1, interleukin (IL)-6, and IL-10 were evaluated in patients successfully withdrawn from immunosuppression. METHODS: Pediatric liver transplant recipients who were successfully withdrawn from immunosuppression (n=12) or who are on minimal immunosuppression (n=7) were genotyped. A control group of liver recipients who required maintenance immunosuppression served as a control group (n=37). RESULTS: Compared to the control group, low TNF- alpha and high/intermediate IL-10 profiles were seen in all 12 children maintained off immunosuppression and in 6 of 7 children requiring minimal immunosuppression. CONCLUSION: Children successfully maintained off immunosuppression are more likely to have a genetic predisposition toward low TNF-alpha and high/intermediate IL-10 production. Children maintained on minimal immunosuppression exhibit a similar cytokine profile to those successfully weaned.