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Effective treatment of solid tumors requires multi-modality approaches. In many patients with stage IV liver disease, current treatments are not curative. Chimeric antigen receptor T cells (CAR-T) are an intriguing option following success in hematological malignancies, but this has not been translated to solid tumors. Limitations include sub-optimal delivery and elevated interstitial fluid pressures. We developed a murine model to test the impact of high-pressure regional delivery (HPRD) on trafficking to liver metastases (LM) and tumor response.CAR-T were generated from CD45.1 mice and adoptively transferred into LM-bearing CD45.2 mice via regional or systemic delivery (RD, SD). Trafficking, tumor growth, and toxicity were evaluated with flow cytometry, tumor bioluminescence (TB, photons/sec logRD of CAR-T was more effective at controlling tumor growth versus SD from post-treatment days (PTD) 2-7 (P = 0.002). HPRD resulted in increased CAR-T penetration versus low-pressure RD (LPRD, P = 0.004), suppression of tumor proliferation (P = 0.03), and trended toward improved long-term control at PTD17 (TB=3.7 versus 6.1, P = 0.47). No LFT increase was noted utilizing HPRD versus LPRD (AST/ALT P = 0.65/0.84) while improved LFTs in RD versus SD groups suggested better tumor control (HPRD AST/ALT P = 0.04/0.04, LPRD AST/ALT P = 0.02/0.02).Cellular immunotherapy is an emerging option for solid tumors. Our model suggests RD and HPRD improved CAR-T penetration into solid tumors with improved short-term tumor control. Barriers associated with SD can be overcome using RD techniques to maximize therapeutic delivery and HPRD may further augment efficacy without increased toxicity.

Colorectal cancer (CRC) is the second leading cause of cancer-related death in Hispanic patients. Screening colonoscopy has been shown to reduce the incidence and mortality of CRC. However, utilization among Hispanic patients and other minority groups is low. The objective of this study was to evaluate colonoscopy utilization among Hispanic patients with a culturally tailored patient navigation program (CTPNP) in place.A CTPNP was designed to meet the needs of the authors' Hispanic patient population and their health care system characteristics. A CTPNP protocol was created, and a Spanish-speaking navigator/coordinator was hired. Enrolled patients received a Spanish-language introductory letter, an initial phone call for patient education, and follow-up calls to ensure that all potential barriers to colonoscopy were overcome. Colonoscopy completion (CC), colonoscopy cancellation (CN), and colonoscopy no-show (NS) rates were recorded and compared with historical rates in Rhode Island.Over a 28-month period, 773 patients were referred to the CTPNP, and 698 (53% female and 47% male) were enrolled in the program. The overall CC rate was 85% (n = 592) with no difference between males and females. The CN rate was 9% (n = 62), and the NS rate was 6% (n = 44). The most common reasons for CN and NS were cost and an inability to contact the patient after referral. Within the CC group, 43% (n = 254) of patients underwent polypectomy, and 1.3% (n = 8) required colectomy. Ninety percent (n = 530) of the CC group reported that they would not have completed colonoscopy without the CTPNP.Implementation of a CTPNP is an effective intervention to improve the CC rate and eliminate the historical gender gap in utilization among Hispanic patients.

Background: Increasing opioid-related deaths have heightened focus on combating the opioid epidemic. The impact of surgical trainees on opioid-related deaths is unclear, and there is little data examining the association between trainee pain management education and opioid prescribing practices. Methods: An anonymous, online survey was distributed to members of the Resident and Associate Society of the American College of Surgeons. The survey covered five themes: education and knowledge, prescribing practices, clinical case scenarios, policy, and beliefs and attitudes. Linear mixed models were used to evaluate the influence of respondent characteristics on reported morphine milligram equivalents (MME) prescribed for common general surgery clinical scenarios. Results: Of 427 respondents, 54 percent indicated receiving training in postoperative pain management during medical school and 66 percent during residency. Only 35 percent agreed that they had received adequate training in prescribing opioids. There was a significant association between undergoing formal pain management training in medical school and prescribing fewer MME for common outpatient general surgery scenarios (94 ± 15.2 vs 108 ± 15.0; p = 0.003). Similarly, formal pain management training in residency was associated with prescribing fewer MME in the survey scenarios (92.6 ± 15.2 vs 109 ± 15.2; p = 0.002). Conclusion: In this survey, nearly two-thirds of surgical residents felt that they were inadequately trained in opioid prescribing. Our findings additionally suggest that improving education may result in increased resident comfort with managing surgical pain, potentially leading to more responsible opioid prescribing. Further work will facilitate residency programs’ development of educational curricula for opioid prescribing best practices.

Effective chimeric antigen receptor-modified T-cell (CAR-T) therapy for liver metastases (LM) will require innovative solutions to ensure efficient delivery and minimization of systemic toxicity. We previously demonstrated the safety of CAR-T hepatic artery infusions (HAI). We subsequently conducted the phase 1b HITM-SIR trial, in which six patients (pts) with CEA+ LM received anti-CEA CAR-T HAIs and selective internal radiation therapy (SIRT). The primary endpoint was safety with secondary assessments of biologic activity. Enrolled pts had a mean LM size of 6.4 cm, 4 pts had >10 LM, and pts received an average of two lines of prior systemic therapy. No grade 4 or 5 toxicities were observed, and there were no instances of severe cytokine-release syndrome (CRS) or neurotoxicity. The mean transduction efficiency was 60.4%. Following CAR-T HAI, reduced levels of GM-CSF-R, IDO, and PD-L1 were detected in LM, and serum CEA levels were stable or decreased in all subjects. Median survival time was 8 months (mean 11, range 4–31). Anti-CEA CAR-T HAI with subsequent SIRT was well tolerated, and biologic responses were demonstrated following failure of conventional therapy. HAI of CAR-T was once again confirmed not to be associated with severe CRS or neurotoxicity.

Metastatic liver tumors have presented challenges with the use of checkpoint inhibitors (CPIs), with only limited success. We hypothesize that regional delivery (RD) of CPIs can improve activity in the liver and minimize systemic exposure, thereby reducing immune-related adverse events (irAE). Using a murine model of colorectal cancer liver metastases (LM), we confirmed high levels of PD-L1 expression on the tumor cells and liver myeloid-derived suppressor cells (L-MDSC). In vivo, we detected improved LM response at 3 mg/kg on PTD7 via portal vein (PV) regional delivery as compared to 3 mg/kg via tail vein (TV) systemic delivery (p = 0.04). The minimal effective dose at PTD7 was 5 mg/kg (p = 0.01) via TV and 0.3 mg/kg (p = 0.02) via PV. We detected 6.7-fold lower circulating CPI antibody levels in the serum using the 0.3 mg/kg PV treatment compared to the 5 mg/kg TV cohort (p &lt, 0.001) without increased liver toxicity. Additionally, 3 mg/kg PV treatment resulted in increased tumor cell apoptotic signaling compared to 5 mg/kg TV (p &lt, 0.05). Therefore, RD of an anti-PD-1 CPI therapy for CRCLM may improve the therapeutic index by reducing the total dose required and limiting the systemic exposure. These advantages could expand CPI indications for liver tumors.

In recent years, cell therapy technologies have resulted in impressive results in hematologic malignancies. Treatment of solid tumors with chimeric antigen receptor T-cells (CAR-T) has been less successful. Solid tumors present challenges not encountered with hematologic cancers, including high intra-tumoral pressure and ineffective CAR-T trafficking to the site of disease. Novel delivery methods may enable CAR-T therapies for solid tumor malignancies. A patient with liver metastases secondary to pancreatic adenocarcinoma received CAR-T targeting carcinoembryonic antigen (CEA). Previously we reported that Pressure-Enabled Drug Delivery (PEDD) enhanced CAR-T delivery to liver metastases 5.2-fold. Three doses of anti-CEA CAR-T were regionally delivered via hepatic artery infusion (HAI) using PEDD technology to optimize the therapeutic index. Interleukin-2 was systemically delivered by continuous intravenous infusion to support CAR-T in vivo. HAI of anti-CEA CAR-T was not associated with any serious adverse events (SAEs) above grade 3 and there were no on-target/off-tumor SAEs. Following CAR-T treatment, positron emission tomography-CT demonstrated a complete metabolic response within the liver, which was durable and sustained for 13 months. The response was accompanied by normalization of serum tumor markers and an abundance of CAR+ cells found within post-treatment tumor specimens. The findings from this report exhibit biologic activity and safety of regionally infused CAR-T for an indication with limited immune-oncology success to date. Further studies will determine how HAI of CAR-T may be included in multidisciplinary treatment plans for patients with liver metastases. ClinicalTrials.gov number, NCT02850536.

We studied prevalence and predictors of meaningful self-reflection among surgical residents and with prompting/structured interventions, sought to improve/sustain resident skills.Residents from six programs recorded 1032 narrative self-reflective comments (120 residents), using a web-based platform. If residents identified something learned or to be improved, self-reflection was deemed meaningful. Independent variables PGY level, resident/surgeon gender, study site/Phase1: July2014-August2015 vs. Phase2: September2015-September2016) were analyzed.Meaningful self-reflection was documented in 40.6% (419/1032) of entries. PGY5's meaningfully self-reflected less than PGY1-4's, 26.1% vs. 49.6% (p = 0.002). In multivariate analysis, resident narratives during Phase 2 were 4.7 times more likely to engage in meaningful self-reflection compared to Phase1 entries (p 0.001). Iterative changes during Phase2 showed a 236% increase in meaningful self-reflection, compared to Phase1.Surgical residents uncommonly practice meaningful self-reflection, even when prompted, and PGY5/chief residents reflect less than more junior residents. Substantial/sustained improvements in resident self-reflection can occur with both training and interventions.

Background Gender and/or gender-stereotypes might influence surgical education. We hypothesized that female surgeons might focus their learning and teaching differently from male surgeons. Methods Residents and surgeons (multi-institutional) individually recorded preoperatively discussed learning objectives (LO) for matching cases. Narratives were classified as knowledge-based, skill-based, or attitude-based. Multinomial logistic regression analyses, LO = dependent variable; independent variables = resident/surgeon gender, PGY level, timing of entry-to-procedure date, and quarters-of-year. Results 727 LOs from 125 residents (41% female) and 49 surgeons (20% female) were classified. Female residents were 1.4 times more likely to select knowledge over skill. With female surgeons, residents were 1.6 and 2.1 times more likely to select knowledge over skill and attitude over skill than if the surgeon was male. PGY 4/5 residents chose attitude-based LOs over junior residents. Conclusion Resident, surgeon gender and year-of-training influence learning objectives. Whether this reflects gender stereotyping by residents or differences in attending teaching styles awaits further exploration.

Resident and curriculum evaluation require tracking surgical resident operative performance, yet what and when to measure remains unclear.From a multi-institutional database, we reviewed 611 resident/surgeon-paired assessments of ACGME Milestones and modified OPRS ratings for different cases and postgraduate years.Faculty Milestone ratings increased with each PGY (p=0.001) and correlated with resident self-ratings (ICC = 0.83). Mean OPRS scores increased in small increments with substantial intra-year variability. Progression among individual OPRS subcategories was not apparent from more global analyses. Interestingly, male faculty offered lower ratings than female faculty.Milestones and modified mean OPRS ratings suggest residents are learning, yet lack sufficient discrimination for promotion or curricular analysis. Differential progression through OPRS subcategories suggests a taxonomy of surgical learning that can be tailored to focus on different skills at each point in the training continuum. The effect of faculty gender on resident ratings awaits further study.

Introduction Efficacy of cellular immunotherapy for liver metastases (LM) has been limited by poor trafficking and elevated intra-tumoral pressures. In a phase 1b study, we found that regional, pressure-enabled drug delivery (PEDD, TriSalus Life Sciences, Inc.) improved LM CAR-T delivery. We hypothesized that PEDD of CAR-T in a murine model can improve LM control. Methods LM bearing CD45.2 mice were treated with CD45.1 anti-CEA CAR-T via systemic delivery (SD, tail vein) or regional delivery (RD, portal vein) at low pressure (LPRD) vs. high pressure (HPRD) to model PEDD. Flow rates were calibrated to achieve LPRD or HPRD. Tumor bioluminescence (TB), flow cytometry (FC), immunofluorescence (IF), & quantitative polymerase chain reaction (qPCR) were assessed on various post-treatment days (PTD). Results FC of liver non-parenchymal cells on PTD7 showed increased CAR-T density in HPRD & LPRD (9.4% & 11.0%, p = 0.03 & 0.002) vs. SD (3.7%). qPCR of the CAR transgene supported this observation, but was not significant (HPRD 135.8, p = 0.76, LPRD 108.6, p = 0.40 vs. SD 69.8). TB was lower in RD vs. SD up to PTD7 (log2 fold-change HPRD −1.3 & LPRD −0.9 vs. SD 4.3, p = 0.005 & 0.006). Tumor proliferation by Ki67 IF was significantly reduced with RD vs. control (HPRD & LPRD, p < 0.001 & p = 0.05) with HPRD superior to LPRD (p = 0.03). Serum liver enzymes were not significantly elevated using HPRD vs. LPRD at PTD7 (AST/ALT 154.7/36.3 vs. 139.1/29.1, p = 0.84/0.67), but did rise at PTD17, correlating with tumor progression (AST/ALT 800.7/229.3 vs. 387.5/139.5, p = 0.10/0.28). Conclusions RD increased LM CAR-T delivery and HPRD showed evidence of improved CAR-T trafficking and tumor control relative to LPRD. Further clinical testing of PEDD is planned for LM cellular therapy.

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Recent work in our lab has demonstrated a role for interleukin-13 receptor alpha 1 (IL-13R[alpha]1) in the induction of apoptosis of T helper type 1 (Th1) cells in the neonatal immune system. Apoptosis of Th1 cells results in neonatal Th2-bias, which confers susceptibility to both microbial infections and allergic reactions. Unfortunately, there have been few molecular tools developed to study IL-13R[alpha]1 in the mouse despite these findings. Therefore, in order to further examine the role of IL-13R[alpha]1 in neonatal immunity, and also in allergy and asthma, we developed a monoclonal antibody that detects IL-13R[alpha]1 and we have generated mice that deficient in the expression of IL-13R[alpha]1. Using these reagents, IL-13R[alpha]1 was found to influence the primary T helper cell response to antigen, which expands upon it's role, since the role of IL-13R[alpha]1 in apoptosis of neonatal Th1 cells was previously observed upon secondary encounter with antigen. Furthermore, we demonstrate that when IL-13R[alhpa]1 deficient T cells are transferred to wild-type BALB/c mice, neonatal Th2-bias is effectively reversed to yield a Th1-dominated response. These observations strengthen IL-13R[alpha]1's candidacy as a molecular target in neonatal vaccines and also in therapies to prevent the formation of allergies.

Adrenocortical oncocytic neoplasms are rare tumors, generally regarded as benign and hormonally nonfunctional. We performed a systematic review to update the literature on adrenocortical oncocytic neoplasms by reviewing patient and tumor characteristics, as well as management trends, because the literature is composed of predominately single-case reports.A systematic search was performed in PubMed, Embase, and Cochrane Library through June 2017. Malignant potential was determined by applying the Lin-Weiss-Bisceglia criteria to cases.Included for analysis were 84 citations describing 140 adrenocortical oncocytic neoplasms, including our own case. These were diagnosed predominantly in females (66%), on the left side (64%), and were nonfunctional (66%). Average age at diagnosis was 44 years (2.5-77), and median tumor size was 80 mm (16-285). A total of 35% of adrenocortical oncocytic neoplasms were benign, 41% borderline, and 24% malignant. Male patients were more likely to have a malignant tumor compared with females (36% versus 18%, P = .035). The 5-year overall survival for benign adrenocortical oncocytic neoplasms was 100%, borderline 88%, and malignant 47%. Hormonal function did not discriminate malignant from benign lesions. Adrenocortical oncocytic neoplasms that stained positive for synaptophysin (50%, P.001) and negative for vimentin (62%, P = .009) are more often benign.We found that the majority of adrenocortical oncocytic neoplasms (65%) were either malignant or had malignant potential, contrary to the previous literature. The Lin-Weiss-Bisceglia criteria are useful in identifying those patients for whom closer surveillance is warranted, because their prognosis is dependent on the Lin-Weiss-Bisceglia diagnosis.

It is increasingly important for faculty to teach deliberately and provide timely, detailed, and formative feedback on surgical trainee performance. We initiated a multicenter study to improve resident evaluative processes and enhance teaching and learning behaviors while engaging residents in their education.Faculty from 7 US postgraduate training programs rated resident operative performances using the perioperative briefing, intraoperative teaching, debriefing model, and rated patient visits/academic performances using the entrustable professional activities model via a web-based platform. Data were centrally analyzed and iterative changes made based on participant feedback, individual preferences, and database refinements, with trends addressed using the Plan, Do, Check, Act improvement methodology.Participants (92 surgeons, 150 residents) submitted 3,880 assessments during July 2014 through September 2017. Evidence of preoperative briefings improved from 33.9% ± 2.5% to 95.5% ± 1.5% between April and September 2014 compared with April and September 2017 (p0.001). Postoperative debriefings improved from 10.6% ± 2.7% to 90.2% ± 2.5% (p0.001) for the same period. Meaningful self-reflection by residents improved from 28.6% to 67.4% (p0.001). The number of assessments received per resident during a 6-month period increased from 6.4 ± 6.2 to 13.4 ± 10.1 (p0.003). Surgeon-entered assessments increased from 364 initially to 685 in the final period, and the number of resident assessments increased from 308 to 445. We showed a 4-fold increase in resident observed activities being rated.By adopting recognized educational models with repeated Plan, Do, Check, Act cycles, we increased the quality of preoperative learning objectives, showed more frequent, detailed, and timely assessments of resident performance, and demonstrated more effective self-reflection by residents. We monitored trends, identified opportunities for improvement and successfully sustained those improvements over time, applying a team-based approach.

Introduction We have demonstrated safety and clinical activity with anti-CEA CAR-T (Sorrento/TNK Therapeutics, Inc.) regional infusions for treatment of liver metastases (LM) using a pressure-enabled drug delivery device (PEDD™, TriSalus™ Life Sciences, Inc.) to increase CAR-T penetration. To further explore the potential benefit of PEDD, we developed a pre-clinical murine LM model that enables correlation of infusion pressure with response. Methodology Mice with CEA+ LM were infused with anti-CEA CAR-T into the portal vein with specified rate and pressure levels. Flow cytometry (FC), bioluminescence imaging (BLI), and serum liver function tests (LFTs) were conducted at multiple time points. Results Flow-pressure relationship was established with ΔP of 7.23 mmHg vs 2.33 mmHg (p=0.01) in high-pressure (10 mL/min, HP) and low-pressure (1 mL/min, LP) cohorts. FC assessment of hepatic non-parenchymal cells 1d after infusion demonstrated 15.9% CD3+CAR+ in HP, compared to 5.1% in LP (p=0.0004). Tumor BLI at day 3 (geometric mean relative to baseline) showed significantly enhanced therapeutic effect in HP, −18% relative signal intensity (RSI), compared to +148% RSI in LP (p=0.05) or +178% RSI in controls (p=0.04). LFTs were similar in LP and HP groups with AST 302 vs 437 U/L (p=0.60) and total bilirubin 0.25 vs 0.7 mg/dL (p=0.33), respectively. Conclusions HP delivery correlated with enhanced CAR-T delivery and control of tumor growth, without an increase in liver toxicity. Follow up to this proof of concept study will investigate multiple infusions with combinatorial approaches with the goal of durable tumor eradication. An ongoing clinical study will further explore CAR-T PEDD in patients.

Introduction Checkpoint inhibitors (CI) have greatly impacted the treatment of solid tumors. Success in the liver has been more limited. When intravenously infused, the CI is delivered predominantly to extrahepatic sites, which results in systemic side effects. Previously, we reported on regional delivery of cellular immunotherapy for liver tumors using pressure-enabled drug delivery (PEDD™, TriSalus™ Life Sciences, Inc.). We hypothesized that PEDD of CI would improve the therapeutic index (TI). Methods In a murine model of colorectal liver metastases (CRLM), we infused high (HP) or low pressure (LP) anti-PD-1 antibodies (RMP1-14) via the portal vein and compared to systemic tail vein delivery (SD) at 0, 0.3, 1.0 and 3.0 mg/kg. Tumor bioluminescence (TB), histopathology, and serologic analysis informed treatment effects and toxicity. Results At a dose of 3mg/kg, LP resulted in similar IVIS TB growth kinetics compared to SD 3 mg/kg at 7 days post-treatment (geometric mean, p = 0.94). In animals treated with a 10-fold lower dose (0.3 mg/kg), tumor growth was significantly lower with HP vs. LP (7.5-fold improvement, p = 0.04). Circulating serum anti-PD-1 levels were similar when we compared SD and LP at 1 and 3 mg/kg (Mean 2512.0 vs. 2250.2 ng/mL, p = 0.25). Comparatively, systemic exposure was significantly lower at 0.3 mg/kg LP (Mean 508.1 ng/mL, p < 0.0001). No increases in hepatotoxicity were seen with PEDD (AST p = 0.57, ALT p = 0.43). Conclusion PEDD of anti-PD-1 CI improved liver tumor control while also limiting systemic exposure. These findings support PEDD for anti-PD-1 therapy to improve TI. Phase 1 exploration of anti-PD-1 PEDD for patients with hepatic malignancy is thus warranted.

In this study, we examined the role IL-13 receptor alpha 1 (IL-13Rα1) plays in macrophage differentiation and function. The findings indicate that IL-13Rα1 is expressed on the M2 but not on the M1 subset of macrophages and specifically heterodimerizes with the IL-4Rα chain to form a type II receptor, which controls the differentiation and function of these cells. Indeed, BM cells from IL-13Rα1(+/+) and IL-13Rα1(-/-) mice yield equivalent numbers of macrophages when cultured under M2 polarizing conditions. However, IL-13Rα1(-/-) BM cells yield a much higher number of macrophages than IL-13Rα1(+/+) BM cells when the differentiation is carried out under M1-polarizing conditions. Further analyses indicated that macrophages that express IL-13Rα1 also display surface markers associated with an M2 phenotype. In addition, the IL-13Rα1(+) macrophages were highly efficient in phagocytizing zymosan bioparticles both in vitro and in vivo, and supported differentiation of naive T cells to a Th2 phenotype. Finally, when stimulated by IL-13, a cytokine that uses the heteroreceptor, the cells were able to phosphorylate STAT6 efficiently. These previously unrecognized findings indicate that IL-13Rα1 serves as a marker for M2 macrophages and the resulting heteroreceptor influences both their differentiation and function.

Primary neonatal T cell responses comprise both T helper (Th) cell subsets, but Th1 cells express high levels of interleukin 13 receptor alpha1 (IL-13R alpha 1), which heterodimerizes with IL-4R alpha. During secondary antigen challenge, Th2-produced IL-4 triggers the apoptosis of Th1 cells via IL-4R alpha/IL-13R alpha 1, thus explaining the Th2 bias in neonates. We show that neonates acquire the ability to overcome the Th2 bias and generate Th1 responses starting 6 d after birth. This transition was caused by the developmental maturation of CD8 alpha(+)CD4(-) dendritic cells (DCs), which were minimal in number during the first few days of birth and produced low levels of IL-12. This lack of IL-12 sustained the expression of IL-13R alpha 1 on Th1 cells. By day 6 after birth, however, a significant number of CD8 alpha(+)CD4(-) DCs accumulated in the spleen and produced IL-12, which triggered the down-regulation of IL-13R alpha 1 expression on Th1 cells, thus protecting them against IL-4-driven apoptosis.

Lately, it has become clear that regulatory T cells (Tregs) play a major role in the maintenance of peripheral tolerance and control of autoimmunity. Despite these critical functions, the process underlying the development of Tregs remains largely undefined. Herein, altered peptide ligand (APL) variants derived from the proteolipid protein-1 (PLP1) epitope were expressed on immunoglobulins (Igs) and the resulting Ig-APLs were used to deliver the APLs from mother to fetus through the maternal placenta to influence thymic T cell selection. This delivery system was then adapted to the SJL/J mouse, a strain that expresses only the DM20 form of PLP, which lacks the dominant PLP1 epitope in the thymus during fetal and neonatal development. This model, which restores thymic T cell selection for PLP1, was then used to determine whether affinity plays a role in the development of Tregs. The findings show that fetal exposure to low-affinity peptide ligand was unable to drive development of Tregs while variants with higher affinity to the TCR resulted in significant seeding of the periphery with mature, naive Tregs. Thus, contrary to pathogenic T cells, Tregs require avid TCR-ligand interaction to undergo thymic development and maturation.

Aman aged 54 years,who had not seen a physician for nearly 10 years, presented to the emergency department with a 1-month history of generalized weakness and bilateral lower extremity swelling that had progressed to his upper abdomen. Physical examination revealed at least 4 lower extremity edemas and an abdomen that was large, taut, and distended (Figure 1A). A computed tomographic scan of the chest, abdomen, and pelvis was obtained (Figure 1B). A

The earliest thymic progenitors (ETPs) were recently shown to give rise to both lymphoid and myeloid cells. Whereas the majority of ETPs are derived from IL-7Rα–positive cells and give rise exclusively to T cells, the origin of the myeloid cells remains undefined. In this study, we show both in vitro and in vivo that IL-13Rα1+ ETPs yield myeloid cells with no potential for maturation into T cells, whereas IL-13Rα1− ETPs lack myeloid potential. Moreover, transfer of lineage-negative IL-13Rα1+ bone marrow stem cells into IL-13Rα1–deficient mice reconstituted thymic IL-13Rα1+ myeloid ETPs. Myeloid cells or macrophages in the thymus are regarded as phagocytic cells whose function is to clear apoptotic debris generated during T cell development. However, the myeloid cells derived from IL-13Rα1+ ETPs were found to perform Ag-presenting functions. Thus, IL-13Rα1 defines a new class of myeloid restricted ETPs yielding APCs that could contribute to development of T cells and the control of immunity and autoimmunity.

A number of Ag-specific approaches have been developed that ameliorate experimental allergic encephalomyelitis (EAE), an animal model for the human autoimmune disease multiple sclerosis. Translation to humans, however, remains a consideration, justifying the search for more insight into the mechanism underlying restoration of self-tolerance. Ig-proteolipid protein (PLP) 1 and Ig-myelin oligodendrocyte glycoprotein (MOG) are Ig chimeras carrying the encephalitogenic PLP 139–151 and MOG 35–55 amino acid sequence, respectively. Ig-PLP1 ameliorates EAE in SJL/J (H-2s) mice while Ig-MOG modulates the disease in C57BL/6 (H-2b) animals. In this study, we asked whether the chimeras would suppress EAE in F1 mice expressing both parental MHC alleles and representing a polymorphism with more relevance to human circumstances. The results show that Ig-MOG modulates both PLP1 and MOG peptide-induced EAE in the F1 mice, whereas Ig-PLP1 counters PLP1 EAE but exacerbates MOG-induced disease. This in trans aggravation of MOG EAE by Ig-PLP1 operates through induction of PLP1-specific T cells producing IL-5 that sustained inhibition of MOG-specific Abs leading to exacerbation of EAE. Thus, in trans T cell tolerance, which should be operative in polymorphic systems, can aggravate rather than ameliorate autoimmunity. This phenomenon possibly takes place through interference with protective humoral immunity.

To date, very few Ag-based regimens have been defined that could expand T regulatory (Treg) cells to reverse autoimmunity. Additional understanding of Treg function with respect to specificity and broad suppression should help overcome these limitations. Ig-proteolipid protein (PLP)1, an Ig carrying a PLP1 peptide corresponding to amino acid residues 139-151 of PLP, displayed potent tolerogenic functions and proved effective against experimental allergic encephalomyelitis (EAE). In this study, we took advantage of the Ig-PLP1 system and the PLP1-specific TCR transgenic 5B6 mouse to define a regimen that could expand Ag-specific Treg cells in vivo and tested for effectiveness against autoimmunity involving diverse T cell specificities. The findings indicate that in vivo exposure to aggregated Ig-PLP1 drives PLP1-specific 5B6 TCR transgenic cells to evolve as Treg cells expressing CD25, CTLA-4, and Foxp3 and producing IL-10. These Treg cells were able to suppress PLP1 peptide-induced EAE in both SJL/J and F1 (SJL/J × C57BL/6) mice. However, despite being effective against disease induced with a CNS homogenate, the Treg cells were unable to counter EAE induced by a myelin basic protein or a myelin oligodendrocyte glycoprotein peptide. Nevertheless, activation with Ag before transfer into the host mice supports suppression of both myelin oligodendrocyte glycoprotein- and myelin basic protein peptide-induced EAE. Thus, it is suggested that activation of Treg cells by the cognate autoantigen is necessary for operation of broad suppressive functions.

Dendritic cells (DCs) are professional antigen presenting cells that are capable of presenting both self and foreign antigens to T cells thereby inducing either tolerance or immunity respectively. What is still not clear is whether T cell tolerance requires a specific subset or any population of DCs can drive tolerance. To address this question different subsets of DCs were tested for suppression of autoimmunity in two major animal models- type I diabetes (T1D) and experimental allergic encephalomyelitis (EAE). There are 3 major subsets of DCs in spleen- CD8α+, CD8α−CD4+ and CD8α−CD4−. In this study we investigated the ability of these subsets to induce tolerance in TID and EAE. Indeed the CD8α−CD4− DC subset mediated protection against diabetes in non-obese diabetic (NOD) mice. In fact, mice had reduced destructive infiltration within the islets and the antigen-specific lymphocytes showed reduced proliferation and an increase in IFNγ and IL-10 response. Surprisingly, in EAE it is the CD8α−CD4+ DC subset that supported protection against the disease. The lymphocytes from treated mice displayed more of a Th1 biased response. Both the protective subsets were mature and expressed significant levels of class II MHC and costimulatory molecules. However, the subsets trafficked differently to spleen and draining lymph nodes. Thus, distinct DC subsets drive tolerance in the two models of autoimmunity despite the fact that both diseases are mediated by CD4+ T cells. Research supported by grants DK65748 and NS37406 from NIH.