Cassie L. Kirby

Eotaxin-3 and a uniquely conserved gene-expression profile in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is an emerging disorder with a poorly understood pathogenesis. In order to define disease mechanisms, we took an empirical approach analyzing esophageal tissue by a genome-wide microarray expression analysis. EE patients had a striking transcript signature involving 1% of the human genome that was remarkably conserved across sex, age, and allergic status and was distinct from that associated with non-EE chronic esophagitis. Notably, the gene encoding the eosinophil-specific chemoattractant eotaxin-3 (also known as CCL26) was the most highly induced gene in EE patients compared with its expression level in healthy individuals. Esophageal eotaxin-3 mRNA and protein levels strongly correlated with tissue eosinophilia and mastocytosis. Furthermore, a single-nucleotide polymorphism in the human eotaxin-3 gene was associated with disease susceptibility. Finally, mice deficient in the eotaxin receptor (also known as CCR3) were protected from experimental EE. These results implicate eotaxin-3 as a critical effector molecule for EE and provide insight into disease pathogenesis.

Interplay of adaptive th2 immunity with eotaxin-3/c-C chemokine receptor 3 in eosinophilic esophagitis.

Background: Pediatric eosinophilic esophagitis (EE) is a recently described disorder associated with atopy. Although studies of esophageal tissue suggest that Th2 cytokines and eotaxin-3 may be crucial in disease pathogenesis, little is known about the systemic immunological phenotypes of children with EE. Objectives: To define the phenotypes of peripheral blood eosinophils and lymphocytes in EE and to examine for correlations between these parameters and tissue eosinophil numbers and disease severity. Patients and Methods: Blood was collected from children with EE, atopic control children without EE, and nonatopic control children without EE. Flow cytometry was used to measure eosinophil expression of chemokine receptor 3 (CCR3) and interleukin-5 receptor-α (IL-5Rα), and intracellular lymphocyte expression of IL-4, IL-5, IL-13, interferon-γ, and tumor necrosis factor-α. Eosinophil numbers and eotaxin-3 mRNA levels were quantitated in esophageal biopsy specimens. Results: Compared with nonatopic control children, EE patients with active disease had increased peripheral blood eosinophil percentages, mean channel of fluorescence (MCF) of CCR3 on eosinophils, and percentage of CD4+ T cells expressing IL-5. Notably, these parameters positively correlated with esophageal eosinophil numbers. Eotaxin-3 tissue expression positively correlated with esophageal eosinophil numbers and peripheral blood eosinophil CCR3 MCF. The percentage of peripheral blood eosinophils, eosinophil CCR3 MCF, and CD4+ T cell expression of IL-5 were lower in EE patients in disease remission than in patients with active disease. Conclusions: Collectively, these studies demonstrate cooperation between systemic CD4+ Th2-cell–mediated immunity and an enhanced eosinophil-CCR3/eotaxin-3 pathway in EE pathogenesis. Furthermore, the imbalanced Th2 immunity and increased CCR3 expression are reversible with disease remission.

Risk of tacrolimus toxicity in CYP3A5 nonexpressors treated with intravenous nicardipine after kidney transplantation.

Background. Tacrolimus is commonly prescribed for immunosuppression, yet it can cause acute and chronic kidney injury. Continuous intravenous nicardipine (CIVN), prescribed for posttransplant hypertension, inhibits tacrolimus metabolism by cytochrome P450 (CYP) 3A4 and could lead to tacrolimus overexposure in patients genetically lacking the alternative pathway for tacrolimus metabolism, CYP3A5. Methods. We compared maximum 12-hr tacrolimus trough levels (MaxC0) and dose-adjusted MaxC0 in 12 cases treated with CIVN immediately after kidney transplantation with 26 controls (no CIVN). CYP3A5 genotype was determined for all cases. Results. Eight cases not expressing CYP3A5 (CYP3A5*3/*3) had higher median MaxC0 (24.3 ng/mL) than four cases expressing CYP3A5 (CYP3A5*1/*1; 13.9 ng/mL, P=0.028) and controls (14.6 ng/mL, P=0.003). Compared with the other two groups combined, CYP3A5*3/*3 cases had higher median dose-adjusted MaxC0 (330 vs. 175, P=0.012), less time to MaxC0 (42 vs. 72 hr, P<0.001), and more scheduled tacrolimus doses held per patient (1.75 vs. 0.4, P=0.007). Six of eight (75%) CYP3A5*3/*3 cases had potentially toxic MaxC0 (>20 ng/mL) compared with none of four CYP3A5*1/*1 cases and 3 of 26 (11.5%) controls (P<0.001, CYP3A5*3/*3 cases vs. all others). Conclusion. CYP3A5 nonexpressors simultaneously treated with tacrolimus and CIVN may be at increased risk for tacrolimus toxicity.

Reliable individualized monitoring improves cholesterol control in kidney transplant recipients.

OBJECTIVE: To develop and evaluate a system for reliable and efficient individualized risk-based monitoring of cholesterol and 11 other tests after kidney transplantation in children. METHODS: We identified system components that drive reliable individualized monitoring and used quality improvement methods to develop and implement interventions, including (1) monitoring schedules individualized by dyslipidemia risk assigned to each patient, (2) automated previsit decision support from our electronic medical record, (3) standardized work flow and responsibility, and (4) automated forwarding of results to providers. We measured the proportion of patients due for cholesterol testing who had it performed within 1 week of their clinic visit and the proportion of patients in our population who achieved low-density lipoprotein (LDL) cholesterol control at baseline and for 2 years after improved monitoring. RESULTS: The proportion of visits in which cholesterol monitoring was completed when indicated improved from 80% to 98% within 8 months and was sustained for more than 1 year. The number of patients with controlled LDL (<130 mg/dL, 3.3 mmol/L) improved from 44 (71%) of 62 at the start of our project to 58 (94%) of 62 (P = .002) at an average follow-up of 24 months. CONCLUSIONS: Using quality improvement and health information technology, we achieved sustained, reliable and efficient personalized monitoring of cholesterol and 11 other tests. This approach enabled substantial improvement in LDL cholesterol control. Structured methods of system redesign that leverage information technology systems hold promise for rapidly achieving reliable individualized care in other settings.

Composite Health Outcomes in Pediatric and Young Adult Kidney Transplant Recipients

Objective To assess composite health outcomes in pediatric and young adult kidney transplant recipients following kidney transplantation. Study design We conducted a cross‐sectional study of all recipients at our center who had a 1‐, 3‐, 5‐, and/or 10‐year transplant anniversary visit between October 2008 and February 2015. The kidney transplant recipients were assessed at each time point according to an outcome measure consisting of 15 pass/fail criteria in 5 domains: allograft health, rejection and immunology, infection, cardiovascular health, and growth. Results We analyzed 148 patients at 231 transplantation anniversary visit time points; 52 of 82 (63%) patients assessed at 1 year had an ideal outcome, meeting at least 13 of the 15 criteria. This decreased to 37% at year 3, 40% at year 5, and 26% at year 10 (P < .01). The most common failures across all time points occurred in the domains of growth (43%‐52% passing) and cardiovascular health (33%‐51% passing). Allograft health declined significantly, decreasing from 74% at year 1 to 33% at year 10 (P < .01). The percentage of patients with graft failure increased from 2.4% at 1 year to 39.5% at 10 years (P < .01), and patient deaths increased from 0 to 11% (P < .01) in the same time frame. Conclusions Ideal outcomes for pediatric kidney transplant recipients decrease over time with growth, cardiovascular health, and allograft health as the primary failure modes. Understanding the composite health of young recipients will allow primary care providers and nephrologists alike to evaluate the overall health of kidney transplant recipients and focus clinical care on the most common sequelae.

Mycophenolate mofetil-related leukopenia in children and young adults following kidney transplantation: Influence of genes and drugs.

MMF is commonly prescribed following kidney transplantation, yet its use is complicated by leukopenia. Understanding the genetics mediating this risk will help clinicians administer MMF safely. We evaluated 284 patients under 21 years of age for incidence and time course of MMF‐related leukopenia and performed a candidate gene association study comparing the frequency of 26 SNPs between cases with MMF‐related leukopenia and controls. We matched cases by induction, steroid duration, race, center, and age. We also evaluated the impact of induction and SNPs on time to leukopenia in all cases. Sixty‐eight (24%) patients had MMF‐related leukopenia, of which 59 consented for genotyping and 38 were matched with controls. Among matched pairs, no SNPs were associated with leukopenia. With non‐depleting induction, UGT2B7‐900A>G (rs7438135) was associated with increased risk of MMF‐related leukopenia (P = .038). Time to leukopenia did not differ between patients by induction agent, but 2 SNPs (rs2228075, rs2278294) in IMPDH1 were associated with increased time to leukopenia. MMF‐related leukopenia is common after transplantation. UGT2B7 may influence leukopenia risk especially in patients without lymphocyte‐depleting induction. IMPDH1 may influence time course of leukopenia after transplant.