Browsing by Author "Troy, Jesse"
Now showing 1 - 13 of 13
Results Per Page
Sort Options
Item Open Access A cord blood monocyte-derived cell therapy product accelerates brain remyelination.(JCI insight, 2016-08-18) Saha, Arjun; Buntz, Susan; Scotland, Paula; Xu, Li; Noeldner, Pamela; Patel, Sachit; Wollish, Amy; Gunaratne, Aruni; Gentry, Tracy; Troy, Jesse; Matsushima, Glenn K; Kurtzberg, Joanne; Balber, Andrew EMicroglia and monocytes play important roles in regulating brain remyelination. We developed DUOC-01, a cell therapy product intended for treatment of demyelinating diseases, from banked human umbilical cord blood (CB) mononuclear cells. Immunodepletion and selection studies demonstrated that DUOC-01 cells are derived from CB CD14+ monocytes. We compared the ability of freshly isolated CB CD14+ monocytes and DUOC-01 cells to accelerate remyelination of the brains of NOD/SCID/IL2Rγnull mice following cuprizone feeding-mediated demyelination. The corpus callosum of mice intracranially injected with DUOC-01 showed enhanced myelination, a higher proportion of fully myelinated axons, decreased gliosis and cellular infiltration, and more proliferating oligodendrocyte lineage cells than those of mice receiving excipient. Uncultured CB CD14+ monocytes also accelerated remyelination, but to a significantly lesser extent than DUOC-01 cells. Microarray analysis, quantitative PCR studies, Western blotting, and flow cytometry demonstrated that expression of factors that promote remyelination including PDGF-AA, stem cell factor, IGF1, MMP9, MMP12, and triggering receptor expressed on myeloid cells 2 were upregulated in DUOC-01 compared to CB CD14+ monocytes. Collectively, our results show that DUOC-01 accelerates brain remyelination by multiple mechanisms and could be beneficial in treating demyelinating conditions.Item Open Access A Phase II Randomized Clinical Trial of the Safety and Efficacy of Intravenous Umbilical Cord Blood Infusion for Treatment of Children with Autism Spectrum Disorder.(The Journal of pediatrics, 2020-07) Dawson, Geraldine; Sun, Jessica M; Baker, Jennifer; Carpenter, Kimberly; Compton, Scott; Deaver, Megan; Franz, Lauren; Heilbron, Nicole; Herold, Brianna; Horrigan, Joseph; Howard, Jill; Kosinski, Andrzej; Major, Samantha; Murias, Michael; Page, Kristin; Prasad, Vinod K; Sabatos-DeVito, Maura; Sanfilippo, Fred; Sikich, Linmarie; Simmons, Ryan; Song, Allen; Vermeer, Saritha; Waters-Pick, Barbara; Troy, Jesse; Kurtzberg, JoanneObjective
To evaluate whether umbilical cord blood (CB) infusion is safe and associated with improved social and communication abilities in children with autism spectrum disorder (ASD).Study design
This prospective, randomized, placebo-controlled, double-blind study included 180 children with ASD, aged 2-7 years, who received a single intravenous autologous (n = 56) or allogeneic (n = 63) CB infusion vs placebo (n = 61) and were evaluated at 6 months postinfusion.Results
CB infusion was safe and well tolerated. Analysis of the entire sample showed no evidence that CB was associated with improvements in the primary outcome, social communication (Vineland Adaptive Behavior Scales-3 [VABS-3] Socialization Domain), or the secondary outcomes, autism symptoms (Pervasive Developmental Disorder Behavior Inventory) and vocabulary (Expressive One-Word Picture Vocabulary Test). There was also no overall evidence of differential effects by type of CB infused. In a subanalysis of children without intellectual disability (ID), allogeneic, but not autologous, CB was associated with improvement in a larger percentage of children on the clinician-rated Clinical Global Impression-Improvement scale, but the OR for improvement was not significant. Children without ID treated with CB showed significant improvements in communication skills (VABS-3 Communication Domain), and exploratory measures including attention to toys and sustained attention (eye-tracking) and increased alpha and beta electroencephalographic power.Conclusions
Overall, a single infusion of CB was not associated with improved socialization skills or reduced autism symptoms. More research is warranted to determine whether CB infusion is an effective treatment for some children with ASD.Item Open Access A Randomized, Placebo-Controlled, Phase II Trial of Intravenous Allogeneic Non-HLA Matched, Unrelated Donor, Cord Blood Infusion for Ischemic Stroke.(Stem cells translational medicine, 2024-02) Laskowitz, Daniel T; Troy, Jesse; Poehlein, Emily; Bennett, Ellen R; Shpall, Elizabeth J; Wingard, John R; Freed, Brian; Belagaje, Samir R; Khanna, Anna; Jones, William; Volpi, John J; Marrotte, Eric; Kurtzberg, JoanneStroke remains a leading cause of death and disability in the US, and time-limited reperfusion strategies remain the only approved treatment options. To address this unmet clinical need, we conducted a phase II randomized clinical trial to determine whether intravenous infusion of banked, non-HLA matched unrelated donor umbilical cord blood (UCB) improved functional outcome after stroke. Participants were randomized 2:1 to UCB or placebo within strata of National Institutes of Health Stroke Scale Score (NIHSS) and study center. Study product was infused 3-10 days following index stroke. The primary endpoint was change in modified Rankin Scale (mRS) from baseline to day 90. Key secondary outcomes included functional independence, NIHSS, the Barthel Index, and assessment of adverse events. The trial was terminated early due to slow accrual and logistical concerns associated with the COVID-19 pandemic, and a total of 73 of a planned 100 participants were included in primary analyses. The median (range) of the change in mRS was 1 point (-2, 3) in UCB and 1 point (-1,4) in Placebo (P = 0.72). A shift analysis comparing the mRS at day 90 utilizing proportional odds modeling showed a common odds ratio of 0.9 (95% CI: 0.4, 2.3) after adjustment for baseline NIHSS and randomization strata. The distribution of adverse events was similar between arms. Although this study did not suggest any safety concerns related to UCB in ischemic stroke, we did not show a clinical benefit in the reduced sample size evaluated.Item Open Access Allogeneic Umbilical Cord Blood Infusion for Adults with Ischemic Stroke: Clinical Outcomes from a Phase I Safety Study.(Stem cells translational medicine, 2018-07) Laskowitz, Daniel T; Bennett, Ellen R; Durham, Rebecca J; Volpi, John J; Wiese, Jonathan R; Frankel, Michael; Shpall, Elizabeth; Wilson, Jeffry M; Troy, Jesse; Kurtzberg, JoanneStroke is a major cause of death and long-term disability, affecting one in six people worldwide. The only currently available approved pharmacological treatment for ischemic stroke is tissue plasminogen activator; however, relatively few patients are eligible for this therapy. We hypothesized that intravenous (IV) infusion of banked unrelated allogeneic umbilical cord blood (UCB) would improve functional outcomes in patients with ischemic stroke. To investigate this, we conducted a phase I open-label trial to assess the safety and feasibility of a single IV infusion of non-human leukocyte antigen (HLA) matched, ABO matched, unrelated allogeneic UCB into adult stroke patients. Ten participants with acute middle cerebral artery ischemic stroke were enrolled. UCB units were matched for blood group antigens and race but not HLA, and infused 3-9 days post-stroke. The adverse event (AE) profile over a 12 month postinfusion period indicated that the treatment was well-tolerated in these stroke patients, with no serious AEs directly related to the study product. Study participants were also assessed using neurological and functional evaluations, including the modified Rankin Score (mRS) and National Institute of Health Stroke Scale (NIHSS). At 3 months post-treatment, all participants had improved by at least one grade in mRS (mean 2.8 ± 0.9) and by at least 4 points in NIHSS (mean 5.9 ± 1.4), relative to baseline. Together, these data suggest that a single i.v. dose of allogeneic non-HLA matched human UCB cells is safe in adults with ischemic stroke, and support the conduct of a randomized, placebo-controlled phase 2 study. Stem Cells Translational Medicine 2018;7:521-529.Item Open Access Autologous Cord Blood Infusions Are Safe and Feasible in Young Children with Autism Spectrum Disorder: Results of a Single-Center Phase I Open-Label Trial.(Stem cells translational medicine, 2017-05) Dawson, Geraldine; Sun, Jessica M; Davlantis, Katherine S; Murias, Michael; Franz, Lauren; Troy, Jesse; Simmons, Ryan; Sabatos-DeVito, Maura; Durham, Rebecca; Kurtzberg, JoanneDespite advances in early diagnosis and behavioral therapies, more effective treatments for children with autism spectrum disorder (ASD) are needed. We hypothesized that umbilical cord blood-derived cell therapies may have potential in alleviating ASD symptoms by modulating inflammatory processes in the brain. Accordingly, we conducted a phase I, open-label trial to assess the safety and feasibility of a single intravenous infusion of autologous umbilical cord blood, as well as sensitivity to change in several ASD assessment tools, to determine suitable endpoints for future trials. Twenty-five children, median age 4.6 years (range 2.26-5.97), with a confirmed diagnosis of ASD and a qualified banked autologous umbilical cord blood unit, were enrolled. Children were evaluated with a battery of behavioral and functional tests immediately prior to cord blood infusion (baseline) and 6 and 12 months later. Assessment of adverse events across the 12-month period indicated that the treatment was safe and well tolerated. Significant improvements in children's behavior were observed on parent-report measures of social communication skills and autism symptoms, clinician ratings of overall autism symptom severity and degree of improvement, standardized measures of expressive vocabulary, and objective eye-tracking measures of children's attention to social stimuli, indicating that these measures may be useful endpoints in future studies. Behavioral improvements were observed during the first 6 months after infusion and were greater in children with higher baseline nonverbal intelligence quotients. These data will serve as the basis for future studies to determine the efficacy of umbilical cord blood infusions in children with ASD. Stem Cells Translational Medicine 2017;6:1332-1339.Item Open Access CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial.(Neurocritical care, 2021-08-23) James, Michael L; Troy, Jesse; Nowacki, Nathaniel; Komisarow, Jordan; Swisher, Christa B; Tucker, Kristi; Hatton, Kevin; Babi, Marc A; Worrall, Bradford B; Andrews, Charles; Woo, Daniel; Kranz, Peter G; Lascola, Christopher; Maughan, Maureen; Laskowitz, Daniel T; CATCH InvestigatorsBackground
Endogenous apolipoprotein (apo) E mediates neuroinflammatory responses and recovery after brain injury. Exogenously administered apoE-mimetic peptides effectively penetrate the central nervous system compartment and downregulate acute inflammation. CN-105 is a novel apoE-mimetic pentapeptide with excellent evidence of functional and histological improvement in preclinical models of intracerebral hemorrhage (ICH). The CN-105 in participants with Acute supraTentorial intraCerebral Hemorrhage (CATCH) trial is a first-in-disease-state multicenter open-label trial evaluating safety and feasability of CN-105 administration in patients with acute primary supratentorial ICH.Methods
Eligible patients were aged 30-80 years, had confirmed primary supratentorial ICH, and were able to intiate CN-105 administration (1.0 mg/kg every 6 h for 72 h) within 12 h of symptom onset. A priori defined safety end points, including hematoma volume, pharmacokinetics, and 30-day neurological outcomes, were analyzed. For clinical outcomes, CATCH participants were compared 1:1 with a closely matched contemporary ICH cohort through random selection. Hematoma volumes determined from computed tomography images on days 0, 1, 2, and 5 and ordinal modified Rankin Scale score at 30 days after ICH were compared.Results
In 38 participants enrolled across six study sites in the United States, adverse events occurred at an expected rate without increase in hematoma expansion or neurological deterioration. CN-105 treatment had an odds ratio (95% confidence interval) of 2.69 (1.31-5.51) for lower 30-day modified Rankin Scale score, after adjustment for ICH score, sex, and race/ethnicity, as compared with a matched contemporary cohort.Conclusions
CN-105 administration represents an excellent translational candidate for treatment of acute ICH because of its safety, dosing feasibility, favorable pharmacokinetics, and possible improvement in neurological recovery.Item Open Access Effect of Autologous Cord Blood Infusion on Motor Function and Brain Connectivity in Young Children with Cerebral Palsy: A Randomized, Placebo-Controlled Trial.(Stem cells translational medicine, 2017-12) Sun, Jessica M; Song, Allen W; Case, Laura E; Mikati, Mohamad A; Gustafson, Kathryn E; Simmons, Ryan; Goldstein, Ricki; Petry, Jodi; McLaughlin, Colleen; Waters-Pick, Barbara; Chen, Lyon W; Wease, Stephen; Blackwell, Beth; Worley, Gordon; Troy, Jesse; Kurtzberg, JoanneCerebral palsy (CP) is a condition affecting young children that causes lifelong disabilities. Umbilical cord blood cells improve motor function in experimental systems via paracrine signaling. After demonstrating safety, we conducted a phase II trial of autologous cord blood (ACB) infusion in children with CP to test whether ACB could improve function (ClinicalTrials.gov, NCT01147653; IND 14360). In this double-blind, placebo-controlled, crossover study of a single intravenous infusion of 1-5 × 107 total nucleated cells per kilogram of ACB, children ages 1 to 6 years with CP were randomly assigned to receive ACB or placebo at baseline, followed by the alternate infusion 1 year later. Motor function and magnetic resonance imaging brain connectivity studies were performed at baseline, 1, and 2 years post-treatment. The primary endpoint was change in motor function 1 year after baseline infusion. Additional analyses were performed at 2 years. Sixty-three children (median age 2.1 years) were randomized to treatment (n = 32) or placebo (n = 31) at baseline. Although there was no difference in mean change in Gross Motor Function Measure-66 (GMFM-66) scores at 1 year between placebo and treated groups, a dosing effect was identified. In an analysis 1 year post-ACB treatment, those who received doses ≥2 × 107 /kg demonstrated significantly greater increases in GMFM-66 scores above those predicted by age and severity, as well as in Peabody Developmental Motor Scales-2 Gross Motor Quotient scores and normalized brain connectivity. Results of this study suggest that appropriately dosed ACB infusion improves brain connectivity and gross motor function in young children with CP. Stem Cells Translational Medicine 2017;6:2071-2078.Item Open Access Factors Associated with Long-Term Risk of Relapse after Unrelated Cord Blood Transplantation in Children with Acute Lymphoblastic Leukemia in Remission.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2017-08) Page, Kristin M; Labopin, Myriam; Ruggeri, Annalisa; Michel, Gerard; Diaz de Heredia, Cristina; O'Brien, Tracey; Picardi, Alessandra; Ayas, Mouhab; Bittencourt, Henrique; Vora, Ajay J; Troy, Jesse; Bonfim, Carmen; Volt, Fernanda; Gluckman, Eliane; Bader, Peter; Kurtzberg, Joanne; Rocha, VandersonFor pediatric patients with acute lymphoblastic leukemia (ALL), relapse is an important cause of treatment failure after unrelated cord blood transplant (UCBT). Compared with other donor sources, relapse is similar or even reduced after UCBT despite less graft-versus-host disease (GVHD). We performed a retrospective analysis to identify risk factors associated with the 5-year cumulative incidence of relapse after UCBT. In this retrospective, registry-based study, we examined the outcomes of 640 children (<18 years) with ALL in first complete remission (CR1; n = 257, 40%) or second complete remission (CR2; n = 383, 60%) who received myeloablative conditioning followed by a single-unit UCBT from 2000 to 2012. Most received antithymocyte globulin (88%) or total body irradiation (TBI; 69%), and cord blood grafts were primarily mismatched at 1 (50%) or 2+ (34%) HLA loci. Considering patients in CR1, the rates of 5-year overall survival (OS), leukemia-free survival (LFS), and relapse were 59%, 52%, and 23%, respectively. In multivariate analysis (MVA), acute GVHD (grades II to IV) and TBI protected against relapse. In patients in CR2, rates of 5-year OS, LFS, and the cumulative incidence of relapse were 46%, 44%, and 28%, respectively. In MVA, longer duration from diagnosis to UCBT (≥30 months) and TBI were associated with decreased relapse risk. Importantly, receiving a fully HLA matched graft was a strong risk factor for increased relapse in MVA. An exploratory analysis of all 640 patients supported the important association between the presence of acute GVHD and less relapse but also demonstrated an increased risk of nonrelapse mortality. In conclusion, the impact of GVHD as a graft-versus-leukemia marker is evident in pediatric ALL after UCBT. Strategies that promote graft-versus-leukemia while harnessing GVHD should be further investigated.Item Open Access Infusion of human umbilical cord tissue mesenchymal stromal cells in children with autism spectrum disorder.(Stem cells translational medicine, 2020-10) Sun, Jessica M; Dawson, Geraldine; Franz, Lauren; Howard, Jill; McLaughlin, Colleen; Kistler, Bethany; Waters-Pick, Barbara; Meadows, Norin; Troy, Jesse; Kurtzberg, JoanneOngoing neuroinflammation may contribute to symptoms of autism spectrum disorder (ASD) in at least a portion of affected individuals. Mesenchymal stromal cells (MSCs) have demonstrated the capacity to modulate neuroinflammation, but safety and feasibility of MSC administration in children with ASD have not been well established. In this open-label, phase I study, 12 children with ASD between 4 and 9 years of age were treated with intravenous (IV) infusions of human cord tissue mesenchymal stromal cells (hCT-MSCs), a third-party MSC product manufactured from unrelated donor umbilical cord tissue. Children received one, two, or three doses of 2 × 106 cells per kilogram at 2-month intervals. Clinical and laboratory evaluations were performed in person at baseline and 6 months and remotely at 12 months after the final infusion. Aside from agitation during the IV placement and infusion in some participants, hCT-MSCs were well tolerated. Five participants developed new class I anti-human leukocyte antigen (HLA) antibodies, associated with a specific lot of hCT-MSCs or with a partial HLA match between donor and recipient. These antibodies were clinically silent and not associated with any clinical manifestations to date. Six of 12 participants demonstrated improvement in at least two ASD-specific measures. Manufacturing and administration of hCT-MSCs appear to be safe and feasible in young children with ASD. Efficacy will be evaluated in a subsequent phase II randomized, placebo-controlled clinical trial.Item Open Access Long-Term Functional Outcomes following Hematopoietic Stem Cell Transplant for Early Infantile Krabbe Disease.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2018-06-19) Allewelt, Heather; Taskindoust, Mahsa; Troy, Jesse; Page, Kristin; Wood, Susan; Parikh, Suhag; Prasad, Vinod K; Kurtzberg, JoanneAllogeneic hematopoietic stem cell transplantation (HSCT) can retard the progression of early infantile Krabbe disease (EIKD). Superior outcomes are achieved if HSCT is performed prior to the onset of symptoms, however little information is available about the long-term outcomes in surviving patients. We now describe functional outcomes in pre-symptomatic infants who underwent HSCT for EIKD at ≤2 months of life. Records of the 19 patients who underwent HSCT for EIKD at ≤2 months of age from 1996-2010 were reviewed. Long-term functional outcomes were compared between those transplanted at <30 days and ≥30 days of life. Median age at transplant was 27 days (range 19-61). Median follow-up of the cohort was 12.6 years. Overall survival at 5 and 10 years post-transplant was 84.2% (95% CI:58.7-94.6%) and 78.6% (95% CI:52.5-91.4%), respectively. More favorable outcomes were seen in patients who underwent HSCT at <30 days of age, particularly in domains of mobility (p=0.01), communication (p=0.02), and feeding (p=0.008). Improved functional outcomes were observed when HSCT was performed in the first month of life, defining a critical period for intervention. These results support the implementation of newborn screening to enable rapid diagnosis and early treatment of infants with EIKD.Item Open Access Motor function and safety after allogeneic cord blood and cord tissue-derived mesenchymal stromal cells in cerebral palsy: An open-label, randomized trial.(Developmental medicine and child neurology, 2022-07-10) Sun, Jessica M; Case, Laura E; McLaughlin, Colleen; Burgess, Alicia; Skergan, Natalie; Crane, Sydney; Jasien, Joan M; Mikati, Mohamad A; Troy, Jesse; Kurtzberg, JoanneAim
To evaluate safety and motor function after treatment with allogeneic umbilical cord blood (AlloCB) or umbilical cord tissue-derived mesenchymal stromal cells (hCT-MSC) in children with cerebral palsy (CP).Method
Ninety-one children (52 males, 39 females; median age 3 years 7 months [range 2-5 years]) with CP due to hypoxic-ischemic encephalopathy, stroke, or periventricular leukomalacia were randomized to three arms: (1) the AlloCB group received 10 × 107 AlloCB total nucleated cells (TNC) per kilogram at baseline (n = 31); (2) the hCT-MSC group received 2 × 106 hCT-MSC at baseline, 3 months, and 6 months (n = 28); (3) the natural history control group received 10 × 107 AlloCB TNC per kilogram at 12 months (n = 31). Motor function was assessed with the Gross Motor Function Measure-66 (GMFM-66) and Peabody Developmental Motor Scale, Second Edition.Results
Infusions (n = 143) were well tolerated, with eight infusion reactions (three in the AlloCB group, five in hCT-MSC) and no other safety concerns. At 12 months, the mean differences (95% confidence intervals [CI]) between actual and expected changes in GMFM-66 score were AlloCB 5.8 points (3.4-8.2), hCT-MSC 4.3 (2.2-6.4), and natural history 3.1 (1.4-5.0). In exploratory, post hoc analysis, the mean GMFM-66 score (95% CI) of the hCT-MSC group was 1.4 points higher than natural history (-1.1 to 4.0; p = 0.27), and the AlloCB group was 3.3 points higher than natural history (0.59-5.93; p = 0.02) after adjustment for baseline Gross Motor Function Classification System level, GMFM-66 score, and etiology.Interpretation
High-dose AlloCB is a potential cell therapy for CP and should be further tested in a randomized, blinded, placebo-controlled trial.Item Open Access Sibling umbilical cord blood infusion is safe in young children with cerebral palsy.(Stem cells translational medicine, 2021-09) Sun, Jessica M; Case, Laura E; Mikati, Mohamad A; M Jasien, Joan; McLaughlin, Colleen; Waters-Pick, Barbara; Worley, Gordon; Troy, Jesse; Kurtzberg, JoannePreclinical and early phase clinical studies suggest that an appropriately dosed umbilical cord blood (CB) infusion has the potential to help improve motor function in young children with cerebral palsy (CP). As many children with CP do not have their own CB available, use of allogeneic cells would extend access to this potentially beneficial therapy to more children. In this phase I, open-label study, 15 children, aged 1 to 6 years, with moderate to severe spastic CP were treated with a single intravenous infusion of allogeneic human leukocyte antigen (HLA) matched or partially matched sibling CB with a cell dose of ≥2.5 × 107 cells/kg based on the pre-cryopreservation count (median infused cell dose, 3.3 × 107 ; range, 1.8-5.2 × 107 ). There were a total of 49 adverse events (AEs) over a 2-year time period, but there were no AEs related to the CB infusions. Specifically, there were no acute infusion reactions and no antibody formation against platelets, red blood cells, or donor-specific HLA antigens. Donor cells were not detected in peripheral blood 6 months later. Six months after infusion, participants were assessed for response and experienced a mean ± SD increase of 4.7 ± 2.5 points on the Gross Motor Function Measure-66 and 1 ± 2.9 points on the Peabody Gross Motor Quotient. Appropriately dosed, allogeneic partially or fully HLA-matched sibling CB infusion is well tolerated and potentially beneficial in young children with CP.Item Open Access T cell-depleted cultured pediatric thymus tissue as a model for some aspects of human age-related thymus involution.(GeroScience, 2021-06) Hale, Laura P; Cheatham, Lynn; Macintyre, Andrew N; LaFleur, Bonnie; Sanders, Brittany; Troy, Jesse; Kurtzberg, Joanne; Sempowski, Gregory DHuman age-related thymus involution is characterized by loss of developing thymocytes and the thymic epithelial network that supports them, with replacement by adipose tissue. The mechanisms that drive these changes are difficult to study in vivo due to constant trafficking to and from the thymus. We hypothesized that the loss of thymocytes that occurs during human thymic organ cultures could model some aspects of thymus involution and begin to identify mechanisms that drive age-related changes in the thymic microenvironment. Potential mechanistically important candidate molecules were initially identified by screening conditioned media from human thymus organ cultures using antibody microarrays. These candidates were further validated using cultured tissue extracts and conditioned media. Results were compared with gene expression studies from a panel of well-characterized (non-cultured) human thymus tissues from human donors aged 5 days to 78 years. L-selectin released into conditioned media was identified as a biomarker for the content of viable thymocytes within the cultured thymus. Levels of the chemokines CCL21 and CXCL12, likely produced by surviving thymic epithelial cells, increased markedly in conditioned media as thymocytes were lost during culture. Native non-cultured thymus from adults older than 18 years also showed a strong trend toward increased CCL21 expression, in conjunction with significant decreases in thymocyte-related mRNAs compared with thymus from subjects younger than 18 years. Together, these findings demonstrate that use of postnatal human thymus organ cultures can model some aspects of human age-related thymic involution.