Patient Determinants for Histologic Diagnosis of NAFLD in the Real World: A TARGET-NASH Study.

Much of the current data on nonalcoholic fatty liver disease (NAFLD) are derived from biopsy-based studies that may introduce ascertainment and selection bias. Selection of patients for liver biopsy has implications for clinical practice and the reported epidemiology of NAFLD. The aim of this study was to determine patient factors predictive of histologic versus empiric clinical diagnosis of NAFLD in real-world practice. Adults from TARGET-NASH were included in this study. Descriptive statistics are provided for the cohort and compare the characteristics of histologic NAFLD versus patients with clinically diagnosed NAFLD, followed by logistic regression and machine-learning models to describe predictors of liver biopsy. The records of 3,474 subjects were analyzed; median age was 59 years, 59% were female, 75% were White, and median body mass index was 32 kg/m2. Using histologic and/or clinical criteria, a diagnosis of nonalcoholic steatohepatitis was made in 37%, and cirrhosis in 33%. Comorbid conditions included cardiovascular disease (19%), mental health diagnoses (49%), and osteoarthritis (10%). Predictors of a biopsy diagnosis included White race, female sex, diabetes, and elevated alanine aminotransferase (ALT). ALT increased the odds of liver biopsy by 14% per 10-point rise. Machine-learning analyses showed non-White patients with ALT <69 had only a 0.06 probability of undergoing liver biopsy. ALT was the dominant variable that determined liver biopsy. Conclusions: In this real-world cohort of patients with NAFLD, two-thirds of patients did not have a liver biopsy. These patients were more likely to be non-White, older, with a normal ALT, showing potential gaps in or knowledge about this population.

A Real-World Observational Cohort of Patients with Hepatocellular Carcinoma: Design and Rationale for TARGET-HCC.

This study describes the design of the TARGET-hepatocellular carcinoma (HCC) cohort and descriptive characteristics of the patient population at diagnosis among those who were enrolled in the cohort across academic and community clinical centers. TARGET-HCC is a 5-year, longitudinal, observational cohort of patients with HCC receiving care in usual clinical practice. Redacted clinical information, obtained from medical records, captures the natural history and management of the disease, including the safety and efficacy of treatment interventions used in usual clinical practice. Patients can complete patient-reported outcome measures and provide biological specimens for future translational studies. The TARGET-HCC study includes adults with histologic, cytologic, or radiologic diagnosis of HCC from academic and community centers in both the United States and Europe. A total of 1,841 participants were enrolled between January 9, 2017, and July 23, 2019, at 67 sites in the United States and Europe. To date, the most common liver disease etiology in the cohort continues to be hepatitis C, although nearly half had a nonviral etiology, including alcohol-related liver disease or nonalcoholic steatohepatitis. Most included patients were diagnosed at an early stage (Barcelona Clinic Liver Cancer Stage [BCLC] 0/A), but only approximately one third underwent curative treatment. Systemic therapy has been used in 7.3% of enrolled patients, including 45.7% of those with BCLC stage C tumors. Conclusion: Overall, the TARGET-HCC cohort allows for the assessment of patient characteristics and investigation of new treatment paradigms and sequencing with existing agents as well as novel regimens for HCC.

Opioid Use Is More Common in Nonalcoholic Fatty Liver Disease Patients with Cirrhosis, Higher BMI, and Psychiatric Disease.

BACKGROUND: Opioid use is a topic of growing concern among patients with nonalcoholic fatty liver disease (NAFLD). Given safety concerns of opioids, proactively identifying subgroups of patients with an increased probability of opioid use may encourage practitioners to recommend alternative therapies for pain, thus reducing the likelihood of opioid misuse. This work assessed the prevalence and patient characteristics associated with opioid use in a real-world cohort of patients with NAFLD. METHODS: TARGET-NASH, an observational study of participants at 55 academic and community sites in the United States, includes patients with NAFLD defined by pragmatic case definitions. Opioid use was defined as any documented opioid prescriptions in the year prior to enrollment. The association between patient characteristics and the odds of opioid use were modeled with stepwise multivariable logistic regression and tree ensemble methods (Classification and regression tree/Boosted Tree). RESULTS: The cohort included 3,474 adult patients with NAFLD including 18.0% with documented opioid use. Variables associated with opioid use included presence of cirrhosis (OR 1.51, 95% CI 1.16-1.98), BMI ≥32 kg/m2 (OR 1.29, 95% CI 1.05-1.59), depression (OR 1.87, 95% CI 1.50-2.33), and anxiety (OR 1.59, 95% CI 1.27-1.98). In the boosted tree analysis, history of back pain, depression, and fibromyalgia had the greatest relative importance in predicting opioid use. CONCLUSION: Prescription opioids were used in nearly 1 of 5 patients with NAFLD. Given the safety concerns of opioids in patients with NAFLD, alternative therapies including low-dose acetaminophen and nonpharmacologic treatments should be considered for these patients.

A Population-Based Exploration of the Social Implications Associated with Cleft Lip and/or Palate.

BACKGROUND: Clefts of the lip and/or palate (CL/P) carry a social stigma that often causes psychosocial stress. The purpose of this study was to consider the association of cleft phenotype and age with self-reported aspects of psychosocial stress. METHODS: Children with nonsyndromic CL/P and unaffected children born between 1997 and 2003 were identified through the North Carolina Birth Defects Monitoring Program and North Carolina birth records, respectively. The psychosocial concerns of children with CL/P were assessed via a 29-question subset of a larger survey. Responses were analyzed according to school age and cleft phenotype (cleft lip with/without cleft alveolus, CL ± A; cleft palate only, CP; or cleft lip with cleft palate, CL + P). RESULTS: Surveys were returned for 176 children with CL/P and 333 unaffected children. When compared with unaffected children, responses differed for CL ± A in 4/29 questions, for CP in 7/29 questions, and for CL + P in 8/29 questions (P < 0.05). When stratified by school age, children with CL/P in elementary, middle, and high school differed from unaffected children by 1/29, 7/29, and 2/29 questions, respectively. Middle school-aged children with CL/P were more affected by aesthetic concerns, bullying, and difficulties with friendship, and social interaction. Children with CL + P reported more severe aesthetic-related concerns than children with CL ± A or CP but experienced similar speech-related distress as children with CP only. CONCLUSION: Social implications associated with CL/P are most pronounced during middle school, and less so during elementary and high school. This information identifies areas of social improvement aimed at reducing the stigma of CL/P.

FOXO3, estrogen receptor alpha, and androgen receptor impact tumor growth rate and infiltration of dendritic cell subsets differentially between male and female mice.

Tumors evade immune recognition and destruction in many ways including the creation of an immune-suppressive tumor microenvironment (TME). Dendritic cells (DC) that infiltrate the TME are tolerogenic, and suppress effector T cells and anti-tumor activity. Previous reports demonstrated that a key regulator of tolerance in DC is the transcription factor FOXO3. Gender disparity has been studied in cancer in relation to incidence, aggressiveness, and prognosis. Few studies have touched on the importance in relation to impact on the immune system. In the current study, we show that there are significant differences in tumor growth between males and females. Additionally, frequencies and the function of FOXO3 expressed by DC subsets that infiltrate tumors vary between genders. Our results show for the first time that DC FOXO3 expression and function is altered in females. In vitro results indicate that these differences may be the result of exposure to estrogen. These differences may be critical considerations for the enhancement of immunotherapy for cancer.

Alcohol exposure differentially effects anti-tumor immunity in females by altering dendritic cell function.

Dendritic cells (DCs) are a critical component of anti-tumor immunity due to their ability to induce a robust immune response to antigen (Ag). Alcohol was previously shown to reduce DC ability to present foreign Ag and promote pro-inflammatory responses in situations of infection and trauma. However the impact of alcohol exposure on generation of an anti-tumor response, especially in the context of generation of an immune vaccine has not been examined. In the clinic, DC vaccines are typically generated from autologous blood, therefore prior exposure to substances such as alcohol may be a critical factor to consider regarding the effectiveness in generating an immune response. In this study, we demonstrate for the first time that ethanol differentially affects DC and tumor Ag-specific T cell responses depending on sex. Signaling pathways were found to be differentially regulated in DC in females compared to males and these differences were exacerbated by ethanol treatment. DC from female mice treated with ethanol were unable to activate Ag-specific cytotoxic T cells (CTL) as shown by reduced expression of CD44, CD69, and decreased production of granzyme B and IFNγ. Furthermore, although FOXO3, an immune suppressive mediator of DC function, was found to be upregulated in DC from female mice, ethanol related suppression was independent of FOXO3. These findings demonstrate for the first time differential impacts of alcohol on the immune system of females compared to males and may be a critical consideration for determining the effectiveness of an immune based therapy for cancer in patients that consume alcohol.

Nasal Airway Dysfunction in Children with Cleft Lip and Cleft Palate: Results of a Cross-Sectional Population-Based Study, with Anatomical and Surgical Considerations.

BACKGROUND: The aesthetic aspects of the cleft lip nasal deformity have been appreciated for over a century, but the functional implications have remained largely underappreciated or misunderstood. This study describes the frequency and severity of nasal obstructive symptoms among children with cleft lip and/or cleft palate, addressing the hypotheses that age, cleft type, and severity are associated with the development of nasal obstructive symptoms. METHODS: Children with nonsyndromic cleft lip and/or cleft palate and a comparison group of unaffected children born from 1997 to 2003 were identified through the North Carolina Birth Defects Monitoring Program and birth certificates. Nasal airway obstruction was measured using the validated Nasal Obstruction Symptom Evaluation scale. RESULTS: The survey was completed by parental proxy for 176 children with cleft lip and/or cleft palate and 333 unaffected children. Nasal obstructive symptoms were more frequently reported in cleft lip with cleft palate compared with unaffected children (p < 0.0001); children who had isolated cleft lip with or without alveolus and isolated cleft palate were not statistically different from unaffected children. Patients with unilateral cleft lip with cleft palate were found to be more severely affected than bilateral cases. Nasal obstruction was observed in early childhood, although severity worsened in adolescence. CONCLUSIONS: This population-based study reports a high prevalence of nasal obstructive symptoms in children with cleft lip and/or cleft palate based on type and severity of the cleft. The authors encourage cleft teams to consider using this or similar screening methods to identify which children may benefit from functional rhinoplasty. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, I.

FOXO3-NF-κB RelA Protein Complexes Reduce Proinflammatory Cell Signaling and Function.

Tumor-associated myeloid cells, including dendritic cells (DCs) and macrophages, are immune suppressive. This study demonstrates a novel mechanism involving FOXO3 and NF-κB RelA that controls myeloid cell signaling and impacts their immune-suppressive nature. We find that FOXO3 binds NF-κB RelA in the cytosol, impacting both proteins by preventing FOXO3 degradation and preventing NF-κB RelA nuclear translocation. The location of protein-protein interaction was determined to be near the FOXO3 transactivation domain. In turn, NF-κB RelA activation was restored upon deletion of the same sequence in FOXO3 containing the DNA binding domain. We have identified for the first time, to our knowledge, a direct protein-protein interaction between FOXO3 and NF-κB RelA in tumor-associated DCs. These detailed biochemical interactions provide the foundation for future studies to use the FOXO3-NF-κB RelA interaction as a target to enhance tumor-associated DC function to support or enhance antitumor immunity.

Regulatory T cells and myeloid-derived suppressor cells in the tumor microenvironment undergo Fas-dependent cell death during IL-2/αCD40 therapy.

Fas ligand expression in certain tumors has been proposed to contribute to immunosuppression and poor prognosis. However, immunotherapeutic approaches may elicit the Fas-mediated elimination of immunosuppressive regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) within tumors that represent major obstacles for cancer immunotherapy. Previously, we showed that IL-2 and agonistic CD40 Ab (αCD40) elicited synergistic antitumor responses coincident with the efficient removal of Tregs and MDSCs. We demonstrate in this study in two murine tumor models that Treg and MDSC loss within the tumor microenvironment after IL-2/αCD40 occurs through a Fas-dependent cell death pathway. Among tumor-infiltrating leukocytes, CD8(+) T cells, neutrophils, and immature myeloid cells expressed Fas ligand after treatment. Fas was expressed by tumor-associated Tregs and immature myeloid cells, including MDSCs. Tregs and MDSCs in the tumor microenvironment expressed active caspases after IL-2/αCD40 therapy and, in contrast with effector T cells, Tregs significantly downregulated Bcl-2 expression. In contrast, Tregs and MDSCs proliferated and expanded in the spleen after treatment. Adoptive transfer of Fas-deficient Tregs or MDSCs into wild-type, Treg-, or MDSC-depleted hosts resulted in the persistence of Tregs or MDSCs and the loss of antitumor efficacy in response to IL-2/αCD40. These results demonstrate the importance of Fas-mediated Treg/MDSC removal for successful antitumor immunotherapy. Our results suggest that immunotherapeutic strategies that include exploiting Treg and MDSC susceptibility to Fas-mediated apoptosis hold promise for treatment of cancer.

Classification, epidemiology, and genetics of orofacial clefts.

Orofacial clefts (OFCs) include a broad range of facial conditions that differ in cause and disease burden. In the published literature, there is substantial ambiguity in both terminology and classification of OFCs. This article discusses the terminology and classification of OFCs and the epidemiology of OFCs. Demographic, environmental, and genetic risk factors for OFCs are described, including suggestions for family counseling. This article enables clinicians to counsel families regarding the occurrence and recurrence of OFCs. Although much of the information is detailed, it is intended to be accessible to all health professionals for use in their clinical practices.

Novel regulation of CD80/CD86-induced phosphatidylinositol 3-kinase signaling by NOTCH1 protein in interleukin-6 and indoleamine 2,3-dioxygenase production by dendritic cells.

Dendritic cells (DC) play a critical role in modulating antigen-specific immune responses elicited by T cells via engagement of the prototypic T cell costimulatory receptor CD28 by the cognate ligands CD80/CD86, expressed on DC. Although CD28 signaling in T cell activation has been well characterized, it has only recently been shown that CD80/CD86, which have no demonstrated binding domains for signaling proteins in their cytoplasmic tails, nonetheless also transduce signals to the DC. Functionally, CD80/CD86 engagement results in DC production of the pro-inflammatory cytokine IL-6, which is necessary for full T cell activation. However, ligation of CD80/CD86 by CTLA4 also induces DC production of the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO), which depletes local pools of the essential amino acid tryptophan, resulting in blockade of T cell activation. Despite the significant role of CD80/CD86 in immunological processes and the seemingly opposing roles they play by producing IL-6 and IDO upon their activation, how CD80/CD86 signal remains poorly understood. We have now found that cross-linking CD80/CD86 in human DC activates the PI3K/AKT pathway. This results in phosphorylation/inactivation of its downstream target, FOXO3A, and alleviates FOXO3A-mediated suppression of IL-6 expression. A second event downstream of AKT phosphorylation is activation of the canonical NF-κB pathway, which induces IL-6 expression. In addition to these downstream pathways, we unexpectedly found that CD80/CD86-induced PI3K signaling is regulated by previously unrecognized cross-talk with NOTCH1 signaling. This cross-talk is facilitated by NOTCH-mediated up-regulation of the expression of prolyl isomerase PIN1, which in turn increases enzyme activity of casein kinase II. Subsequently, phosphatase and tensin homolog (which suppresses PI3K activity) is inactivated via phosphorylation by casein kinase II. This results in full activation of PI3K signaling upon cross-linking CD80/CD86. Similar to IL-6, we have found that CD80/CD86-induced IDO production by DC at late time points is also dependent upon the PI3K → AKT → NF-κB pathway and requires cross-talk with NOTCH signaling. These data further suggest that the same signaling pathways downstream of DC CD80/CD86 cross-linking induce early IL-6 production to enhance T cell activation, followed by later IDO production to self-limit this activation. In addition to characterizing the pathways downstream of CD80/CD86 in IL-6 and IDO production, identification of a novel cross-talk between NOTCH1 and PI3K signaling may provide new insights in other biological processes where PI3K signaling plays a major role.

High-avidity T cells are preferentially tolerized in the tumor microenvironment.

One obstacle in eliciting potent antitumor immune responses is the induction of tolerance to tumor antigens. TCR(lo) mice bearing a TCR transgene specific for the melanoma antigen tyrosinase-related protein-2 (TRP-2, Dct) harbor T cells that maintain tumor antigen responsiveness but lack the ability to control melanoma outgrowth. We used this model to determine whether higher avidity T cells could control tumor growth without becoming tolerized. As a part of the current study, we developed a second TRP-2-specific TCR transgenic mouse line (TCR(hi)) that bears higher avidity T cells and spontaneously developed autoimmune depigmentation. In contrast to TCR(lo) T cells, which were ignorant of tumor-derived antigen, TCR(hi) T cells initially delayed subcutaneous B16 melanoma tumor growth. However, persistence in the tumor microenvironment resulted in reduced IFN-γ production and CD107a (Lamp1) mobilization, hallmarks of T-cell tolerization. IFN-γ expression by TCR(hi) T cells was critical for upregulation of MHC-I on tumor cells and control of tumor growth. Blockade of PD-1 signals prevented T-cell tolerization and restored tumor immunity. Depletion of tumor-associated dendritic cells (TADC) reduced tolerization of TCR(hi) T cells and enhanced their antitumor activity. In addition, TADCs tolerized TCR(hi) T cells but not TCR(lo) T cells in vitro. Our findings show that T-cell avidity is a critical determinant of not only tumor control but also susceptibility to tolerization in the tumor microenvironment. For this reason, care should be exercised when considering T-cell avidity in designing cancer immunotherapeutics.

FOXO3: A master switch for regulating tolerance and immunity in dendritic cells.

Recent findings demonstrate that dendritic cells in prostate tumors induce immune tolerance in tumor antigen-specific CD8(+) T cells. We propose that DC tolerogenicity can be regulated by expression of Foxo3; silencing Foxo3 expression enhances anti-tumor immune responses and renders FOXO3 a potential target for immunotherapy.

Isolation of immune cells from primary tumors.

Tumors create a unique immunosuppressive microenvironment (tumor microenvironment, TME) whereby leukocytes are recruited into the tumor by various chemokines and growth factors. However, once in the TME, these cells lose the ability to promote anti-tumor immunity and begin to support tumor growth and down-regulate anti-tumor immune responses. Studies on tumor-associated leukocytes have mainly focused on cells isolated from tumor-draining lymph nodes or spleen due to the inherent difficulties in obtaining sufficient cell numbers and purity from the primary tumor. While identifying the mechanisms of cell activation and trafficking through the lymphatic system of tumor bearing mice is important and may give insight to the kinetics of immune responses to cancer, in our experience, many leukocytes, including dendritic cells (DCs), in tumor-draining lymph nodes have a different phenotype than those that infiltrate tumors. Furthermore, we have previously demonstrated that adoptively-transferred T cells isolated from the tumor-draining lymph nodes are not tolerized and are capable of responding to secondary stimulation in vitro unlike T cells isolated from the TME, which are tolerized and incapable of proliferation or cytokine production. Interestingly, we have shown that changing the tumor microenvironment, such as providing CD4(+) T helper cells via adoptive transfer, promotes CD8(+) T cells to maintain pro-inflammatory effector functions. The results from each of the previously mentioned studies demonstrate the importance of measuring cellular responses from TME-infiltrating immune cells as opposed to cells that remain in the periphery. To study the function of immune cells which infiltrate tumors using the Miltenyi Biotech isolation system, we have modified and optimized this antibody-based isolation procedure to obtain highly enriched populations of antigen presenting cells and tumor antigen-specific cytotoxic T lymphocytes. The protocol includes a detailed dissection of murine prostate tissue from a spontaneous prostate tumor model (TRansgenic Adenocarcinoma of the Mouse Prostate -TRAMP) and a subcutaneous melanoma (B16) tumor model followed by subsequent purification of various leukocyte populations.

MicroRNA-1 is a candidate tumor suppressor and prognostic marker in human prostate cancer.

We previously reported that miR-1 is among the most consistently down-regulated miRs in primary human prostate tumors. In this follow-up study, we further corroborated this finding in an independent data set and made the novel observation that miR-1 expression is further reduced in distant metastasis and is a candidate predictor of disease recurrence. Moreover, we performed in vitro experiments to explore the tumor suppressor function of miR-1. Cell-based assays showed that miR-1 is epigenetically silenced in human prostate cancer. Overexpression of miR-1 in these cells led to growth inhibition and down-regulation of genes in pathways regulating cell cycle progression, mitosis, DNA replication/repair and actin dynamics. This observation was further corroborated with protein expression analysis and 3'-UTR-based reporter assays, indicating that genes in these pathways are either direct or indirect targets of miR-1. A gene set enrichment analysis revealed that the miR-1-mediated tumor suppressor effects are globally similar to those of histone deacetylase inhibitors. Lastly, we obtained preliminary evidence that miR-1 alters the cellular organization of F-actin and inhibits tumor cell invasion and filipodia formation. In conclusion, our findings indicate that miR-1 acts as a tumor suppressor in prostate cancer by influencing multiple cancer-related processes and by inhibiting cell proliferation and motility.

Immune suppression in the tumor microenvironment: a role for dendritic cell-mediated tolerization of T cells.

Immune suppression remains a consistent obstacle to successful anti-tumor immune responses. As tumors develop, they create a microenvironment that not only supports tumor growth and metastasis but also reduces potential adaptive immunity to tumor antigens. Among the many components of this tumor microenvironment is a population of dendritic cells which exert profound immune suppressive effects on T cells. In this review, we discuss our recent findings related to these tumor-associated dendritic cells and how targeting them may serve to generate more durable anti-tumor immune responses.

FOXO3 programs tumor-associated DCs to become tolerogenic in human and murine prostate cancer.

The limited success of cancer immunotherapy is often attributed to the loss of antigen-specific T cell function in situ. However, the mechanism for this loss of function is unknown. In this study, we describe a population of tumor-associated DCs (TADCs) in both human and mouse prostate cancer that tolerizes and induces suppressive activity in tumor-specific T cells. In tumors from human prostate cancer patients and transgenic adenocarcinoma of the mouse prostate (TRAMP) mice, TADCs expressed elevated levels of FOXO3 and Foxo3, respectively, which correlated with expression of suppressive genes that negatively regulate T cell function. Silencing FOXO3 and Foxo3 with siRNAs abrogated the ability of human and mouse TADCs, respectively, to tolerize and induce suppressive activity by T cells. Silencing Foxo3 in mouse TADCs was also associated with diminished expression of tolerogenic mediators, such as indoleamine-2,3-dioxygenase, arginase, and TGF-ß, and upregulated expression of costimulatory molecules and proinflammatory cytokines. Importantly, transfer of tumor-specific CD4+ Th cells into TRAMP mice abrogated TADC tolerogenicity, which was associated with reduced Foxo3 expression. These findings demonstrate that FOXO3 may play a critical role in mediating TADC-induced immune suppression. Moreover, our results identify what we believe to be a novel target for preventing CTL tolerance and enhancing immune responses to cancer by modulating the immunosuppressive activity of TADCs found in the tumor microenvironment.

Immunity to murine prostatic tumors: continuous provision of T-cell help prevents CD8 T-cell tolerance and activates tumor-infiltrating dendritic cells.

We reported previously that tumor-specific CD8(+) T cells (TcR-I) become tolerant in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. In this study, we show that CD4(+) TcR transgenic (TcR-II) T cells transferred into TRAMP mice became activated in lymph nodes, trafficked to the prostate, and initially functioned as T(H)1 cells. Although a single cotransfer of TcR-II cells delayed TcR-I cell tolerization, repeated transfer of TcR-II cells was required to prevent TcR-I cell tolerization and significantly slowed progression of TRAMP prostate tumors. After transfer of TcR-II cells, dendritic cells within the tumor expressed higher levels of costimulatory molecules and displayed an enhanced ability to stimulate proliferation of naive T cells. Blockade of CD40-CD40L interactions during TcR-II transfer resulted in a profound reduction in dendritic cell stimulatory capacity and a partial loss of TcR-I effector functions and tumor immunity. These data show that sustained provision of activated tumor-specific CD4(+) T cells alters the immunosuppressive tumor microenvironment, ultimately leading to the control of tumor growth. These findings will assist in the design of more effective immunotherapeutic approaches for cancer.

Functional plasticity of macrophages: in situ reprogramming of tumor-associated macrophages.

The extent to which the functional heterogeneity of Mvarphis is dependent on the differentiation of functional sublineages remains unresolved. One alternative hypothesis proposes that Mvarphis are functionally plastic cells, which are capable of altering their functional activities progressively in response to progressively changing signaling molecules generated in their microenvironment. This "functional plasticity" hypothesis predicts that the functionally polarized Mvarphis in chronic pathologies do not represent Mvarphi sublineages but rather, are mutable phenotypes sustained by chronic signaling from the pathological environment. Solid TAMvarphis are chronically polarized to provide activities that support tumor growth and metastasis and suppress adaptive immune responses. In support of the functional plasticity hypothesis, administration of slow-release microsphere-encapsulated IL-12 successfully reprogrammed TAMvarphis in situ, reducing Mvarphi support of tumor growth and metastasis and enhancing Mvarphi proimmunogenic activities. Increased knowledge of how Mvarphi function is regulated and how polarized Mvarphis can be reprogrammed in situ will increase our ability to control Mvarphi function in a variety of pathological states, including cancer and chronic inflammatory disease.

Rapid release of cytoplasmic IL-15 from tumor-associated macrophages is an initial and critical event in IL-12-initiated tumor regression.

This study reveals that the IL-15 rapidly released into serum upon IL-12 injection into tumor-bearing mice is critical for the subsequent leukocytic infiltration of the tumor and tumor-bearing tissue. The increase in serum IL-15 occurs within 2 h after IL-12 injection concomitantly with a decrease in cytoplasmic IL-15 in tumor-associated Mphi (TAM). Injection of anti-IL-15 one hour prior to IL-12 abrogates subsequent leukocytic infiltration into the tumor and prevents the IL-12-induced reduction of primary tumor mass and the clearance of metastases. Administration of anti-IL-15 18 h after IL-12 did not have a detectable impact on IL-12-induced leukocytic infiltration of the tumor. Deletion of NK cells had no impact on the IL-12-induced change in the functional phenotype of TAM or on the subsequent initiation of leukocytic infiltration of the tumor. In concert with our previous studies demonstrating that IL-12 reduces tumor-supportive activities of TAM, the current study supports the hypothesis that functional re-programming of TAM not only undermines Mphi support for tumor growth but also contributes to a critical step in the initiation of anti-tumor immune responses. In this context, the functional plasticity and pro-immunogenic potential of TAM may constitute a significant and unappreciated target in existing cytokine therapies.