IgE repertoire and immunological memory: compartmental regulation and antibody function.

It is now generally recognized that bone marrow is the survival niche for antigen-specific plasma cells with long-term immunological memory. These cells release antibodies into the circulation, needed to prime effector cells in the secondary immune response. These antibodies participate in the surveillance for antigen and afford immune defence against pathogens and toxins previously encountered in the primary immune response. IgE antibodies function together with their effector cells, mast cells, to exert 'immediate hypersensitivity' in mucosal tissues at the front line of immune defence. The constant supply of IgE antibodies from bone marrow plasma cells allows the rapid 'recall response' by mast cells upon re-exposure to antigen even after periods of antigen absence. The speed and sensitivity of the IgE recall response and potency of the effector cell functions are advantageous in the early detection and elimination of pathogens and toxins at the sites of attack. Local antigen provocation also stimulates de novo synthesis of IgE or its precursors of other isotypes that undergo IgE switching in the mucosa. This process, however, introduces a delay before mast cells can be sensitized and resume activity; this is terminated shortly after the antigen is eliminated. Recent results from adaptive immune receptor repertoire sequencing of immunoglobulin genes suggest that the mucosal IgE+ plasmablasts, which have undergone affinity maturation in the course of their evolution in vivo, are a source of long-lived IgE+ plasma cells in the bone marrow that are already fully functional.

Antibodies and superantibodies in patients with chronic rhinosinusitis with nasal polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps is associated with local immunoglobulin hyperproduction and the presence of IgE antibodies against Staphylococcus aureus enterotoxins (SAEs). Aspirin-exacerbated respiratory disease is a severe form of chronic rhinosinusitis with nasal polyps in which nearly all patients express anti-SAEs. OBJECTIVES: We aimed to understand antibodies reactive to SAEs and determine whether they recognize SAEs through their complementarity-determining regions (CDRs) or framework regions. METHODS: Labeled staphylococcal enterotoxin (SE) A, SED, and SEE were used to isolate single SAE-specific B cells from the nasal polyps of 3 patients with aspirin-exacerbated respiratory disease by using fluorescence-activated cell sorting. Recombinant antibodies with "matched" heavy and light chains were cloned as IgG1, and those of high affinity for specific SAEs, assayed by means of ELISA and surface plasmon resonance, were recloned as IgE and antigen-binding fragments. IgE activities were tested in basophil degranulation assays. RESULTS: Thirty-seven SAE-specific, IgG- or IgA-expressing B cells were isolated and yielded 6 anti-SAE clones, 2 each for SEA, SED, and SEE. Competition binding assays revealed that the anti-SEE antibodies recognize nonoverlapping epitopes in SEE. Unexpectedly, each anti-SEE mediated SEE-induced basophil degranulation, and IgG1 or antigen-binding fragments of each anti-SEE enhanced degranulation by the other anti-SEE. CONCLUSIONS: SEEs can activate basophils by simultaneously binding as antigens in the conventional manner to CDRs and as superantigens to framework regions of anti-SEE IgE in anti-SEE IgE-FcεRI complexes. Anti-SEE IgG1s can enhance the activity of anti-SEE IgEs as conventional antibodies through CDRs or simultaneously as conventional antibodies and as "superantibodies" through CDRs and framework regions to SEEs in SEE-anti-SEE IgE-FcεRI complexes.

Final analysis of a phase II study of modified FOLFIRINOX in locally advanced and metastatic pancreatic cancer.

BACKGROUND: Modifications of FOLFIRINOX are widely used despite the absence of prospective data validating efficacy in metastatic disease (metastatic pancreatic cancer (MPC)) or locally advanced pancreatic cancer (LAPC). We conducted a multicentre phase II study of modified FOLFIRINOX in advanced pancreatic cancer to assess the impact of dose attenuation in MPC and efficacy in LAPC. METHODS: Patients with untreated MPC or LAPC received modified FOLFIRINOX (irinotecan and bolus 5-fluorouracil reduced by 25%). Adverse events (AEs) were compared with full-dose FOLFIRINOX. Response rate (RR), median progression-free survival (PFS) and median overall survival (OS) were determined. RESULTS: In total, 31 and 44 patients with LAPC and MPC were enrolled, respectively. In MPC, efficacy of modified FOLFIRINOX was comparable with FOLFIRINOX with RR 35.1%, OS 10.2 months (95% CI 7.65-14.32) and PFS 6.1 months (95% CI 5.19-8.31). In LAPC, efficacy was notable with RR 17.2%, resection rate 41.9%, PFS 17.8 months (95% CI 11.0-23.9) and OS 26.6 months (95% CI 16.7, NA). Neutropenia (P<0.0001), vomiting (P<0.001) and fatigue (P=0.01) were significantly decreased. [(18)F]-Fluorodeoxyglucose positron emission tomography imaging response did not correlate with PFS or OS. CONCLUSIONS: In this first prospective study of modified FOLFIRINOX in MPC and LAPC, we observed decreased AEs compared with historical control patients. In MPC, the efficacy appears comparable with FOLFIRINOX. In LAPC, PFS and OS were prolonged and support the continued use of FOLFIRINOX in this setting.

Locally advanced unresectable pancreatic cancer.

Twenty-five percent of patients with pancreatic cancer present with locally advanced disease that is unresectable, and the treatment strategy for these patients is controversial, with options including chemotherapy alone, concurrent chemoradiation, or induction chemotherapy followed by chemoradiation. Abstracts presented at the 2014 American Society of Clinical Oncology (ASCO) Annual Meeting (#4001, #4126, and #4024) addressed local control, quality of life, and prognostic factors associated with current regimens of induction chemotherapy and subsequent chemoradiation.

FDG PET/CT Imaging 1 Week after a Single Dose of Pembrolizumab Predicts Treatment Response in Patients with Advanced Melanoma.

PURPOSE: Immunologic response to anti-programmed cell death protein 1 (PD-1) therapy can occur rapidly with T-cell responses detectable in as little as one week. Given that activated immune cells are FDG avid, we hypothesized that an early FDG PET/CT obtained approximately 1 week after starting pembrolizumab could be used to visualize a metabolic flare (MF), with increased tumor FDG activity due to infiltration by activated immune cells, or a metabolic response (MR), due to tumor cell death, that would predict response. PATIENTS AND METHODS: Nineteen patients with advanced melanoma scheduled to receive pembrolizumab were prospectively enrolled. FDG PET/CT imaging was performed at baseline and approximately 1 week after starting treatment. FDG PET/CT scans were evaluated for changes in maximum standardized uptake value (SUVmax) and thresholds were identified by ROC analysis; MF was defined as >70% increase in tumor SUVmax, and MR as >30% decrease in tumor SUVmax. RESULTS: An MF or MR was identified in 6 of 11 (55%) responders and 0 of 8 (0%) nonresponders, with an objective response rate (ORR) of 100% in the MF-MR group and an ORR of 38% in the stable metabolism (SM) group. An MF or MR was associated with T-cell reinvigoration in the peripheral blood and immune infiltration in the tumor. Overall survival at 3 years was 83% in the MF-MR group and 62% in the SM group. Median progression-free survival (PFS) was >38 months (median not reached) in the MF-MR group and 2.8 months (95% confidence interval, 0.3-5.2) in the SM group (P = 0.017). CONCLUSIONS: Early FDG PET/CT can identify metabolic changes in melanoma metastases that are potentially predictive of response to pembrolizumab and significantly correlated with PFS.

Is there a role of radiotherapy in the management of pancreatic neuroendocrine tumors (PNET)?

Pancreatic neuroendocrine tumors (PNET) represent a heterogeneous group of tumors with varying tumor biology and prognosis. Advanced PNETs remain a difficult therapeutic challenge because of their high malignant potential and their resistance to conventional chemotherapy although there have been recent developments with promising results with the use of novel agents for the treatment of this disease. Combined modality chemoradiation is not widely used in the management of locally advanced pancreatic endocrine tumors. We discuss Abstract #335 from 2012 ASCO GI Cancers Symposium and share our experience to discuss efficacy and toxicity of concurrent capecitabine or infusional 5-fluorouracil and radiotherapy in patients with resected, locally advanced and metastatic PNET. Prospective studies to investigate the role of radiation and chemoradiation are warranted.

Using CD69 PET Imaging to Monitor Immunotherapy-Induced Immune Activation.

ABSTRACT: Immune checkpoint inhibitors (ICI) have been effective in treating a subset of refractory solid tumors, but only a small percentage of treated patients benefit from these therapies. Thus, there is a clinical need for reliable tools that allow for the early assessment of response to ICIs, as well as a preclinical need for imaging tools that aid in the future development and understanding of immunotherapies. Here we demonstrate that CD69, a canonical early-activation marker expressed on a variety of activated immune cells, including cytotoxic T cells and natural killer (NK) cells, is a promising biomarker for the early assessment of response to immunotherapies. We have developed a PET probe by radiolabeling a highly specific CD69 mAb, H1.2F3, with Zirconium-89 (89Zr), [89Zr]-deferoxamine (DFO)-H1.2F3. [89Zr]-DFO-H1.2F3 detected changes in CD69 expression on primary mouse T cells in vitro and detected activated immune cells in a syngeneic tumor immunotherapy model. In vitro uptake studies with [89Zr]-DFO-H1.2F3 showed a 15-fold increase in CD69 expression for activated primary mouse T cells, relative to untreated resting T cells. In vivo PET imaging showed that tumors of ICI-responsive mice had greater uptake than the tumors of nonresponsive and untreated mice. Ex vivo biodistribution, autoradiography, and IHC analyses supported the PET imaging findings. These data suggest that the CD69 PET imaging approach detects CD69 expression with sufficient sensitivity to quantify immune cell activation in a syngeneic mouse immunotherapy model and could allow for the prediction of therapeutic immune responses to novel immunotherapies.

Locally advanced pancreatic adenocarcinoma: where are we and where are we going? Highlights from the "2011 ASCO Gastrointestinal Cancers Symposium". San Francisco, CA, USA. January 20-22, 2011.

Eight abstracts highlighting the continued evolution of the management of locally advanced pancreatic cancer were presented at the 2011 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium (Abstracts #195, #239, #259, #281, #287, #305, #307, #324). These studies address key issues including the role of novel targeted therapies, what chemotherapy regimen should be used in conjunction with radiotherapy, and whether locally advanced pancreatic cancer can be managed with chemotherapy alone.

Linear combinations of docking affinities explain quantitative differences in RTK signaling.

Receptor tyrosine kinases (RTKs) process extracellular cues by activating a broad array of signaling proteins. Paradoxically, they often use the same proteins to elicit diverse and even opposing phenotypic responses. Binary, 'on-off' wiring diagrams are therefore inadequate to explain their differences. Here, we show that when six diverse RTKs are placed in the same cellular background, they activate many of the same proteins, but to different quantitative degrees. Additionally, we find that the relative phosphorylation levels of upstream signaling proteins can be accurately predicted using linear models that rely on combinations of receptor-docking affinities and that the docking sites for phosphoinositide 3-kinase (PI3K) and Shc1 provide much of the predictive information. In contrast, we find that the phosphorylation levels of downstream proteins cannot be predicted using linear models. Taken together, these results show that information processing by RTKs can be segmented into discrete upstream and downstream steps, suggesting that the challenging task of constructing mathematical models of RTK signaling can be parsed into separate and more manageable layers.

Updates in locally advanced pancreatic cancer. Highlights from the "2010 ASCO Annual Meeting". Chicago, IL, USA. June 4-8, 2010.

Pancreatic cancer is the 4th leading cancer cause mortality in both men and women. Pancreatic cancer is usually diagnosed in the advanced setting, and only 10-15% of patients present with operable disease. About 25% are locally advanced and unresectable and the rest are metastatic. Studies presented at the 2010 American Society of Clinical Oncology (ASCO) Annual Meeting highlighted both current treatment options and promising novel therapeutic agents and approaches.

Combining epidermal growth factor receptor inhibitors and radiation therapy in pancreatic cancer: small step or giant leap?

Targeting the epidermal growth factor receptor (EGFR) with small molecule inhibitors or monoclonal antibodies in combination with chemotherapy and radiation is a theoretically appealing strategy in pancreatic cancer. EGFR inhibitors have shown efficacy as radiosensitizers and activity against metastatic pancreatic cancer when combined with gemcitabine. This paper examines the available clinical data, with a focus on locally advanced, unresectable disease. Further studies with a focus on understanding the basic biology of EGFR inhibition are needed to identify an optimal multi-modality regimen.

New developments in the treatment of locally advanced pancreatic cancer. Highlights from the 45th ASCO annual meeting. Orlando, FL, USA. May 29-June 2, 2009.

The results of the trials presented at this year's ASCO annual meeting underline the challenges of not only treating but also studying locally advanced pancreatic cancer, with any appreciable effect of treatment gained at the cost of considerable toxicity. That response was observed in small numbers of patients in the presented trials speaks to the importance of rational selection of treatment in individual patients in order to achieve maximal survival with minimal treatment-associated morbidity. Further understanding of tumor biology and identification of both prognostic and predictive factors will help define personalized treatment approaches for individual patients.

Stereotactic body radiation therapy (SBRT) in pancreatic cancer: is it ready for prime time?

Pancreatic cancer is a devastating disease with few effective treatment modalities. Stereotactic body radiation therapy is a novel technique that takes advantage of the technologic advancements in image guidance and radiation dose delivery to direct ablative doses to tumors with acceptable toxicity that was not previously achievable with conventional techniques. Recent literature contains reports of stereotactic body radiation therapy in patients with locally advanced pancreatic tumors. This paper presents a summary of the current data and highlights the limitations and the promise. Further clinical study in the form of multi-institutional trials is warranted to establish the role of stereotactic body radiation therapy as a comparable noninvasive alternative to surgery.

Chemoradiation after FOLFIRINOX for borderline resectable or locally advanced pancreatic cancer.

BACKGROUND: The safety and efficacy of FOLFIRINOX (FX) followed by consolidative chemoradiation (CRT) in borderline resectable (BRPC) and locally advanced pancreatic cancer (LAPC) has not been extensively studied. We sought to evaluate outcomes and toxicities of this regimen. METHODS: A retrospective review was performed of 33 patients with BRPC or LAPC treated with FX followed by CRT. Radiotherapy was directed at the primary tumor and any involved nodes (84.8% received 50-50.4 Gy with standard fractionation and concurrent capecitabine, while 15.2% of patients received 36 Gy in 15 fractions with weekly gemcitabine). Toxicities of FX and CRT were graded using Common Terminology Criteria for Adverse Events (CTCAE v4.0), and radiographic response was evaluated using Response Evaluation Criteria in Solid Tumors (RECIST). Overall survival (OS), distant metastasis-free survival (DMFS), and local control (LC) were calculated using Kaplan-Meier analyses, and a Cox proportional hazards model was used to assess the impact of clinicopathologic factors on OS. RESULTS: Median follow-up was 19.9 months and patients received a median of 6.4 months of chemotherapy (range, 2.2-12.0 months). There were more T4 tumors than T3 tumors (70% vs. 30%). Grade ≥3 toxicities were low, including fatigue (9.1%), diarrhea (6.1%), neuropathy (6.1%), and dehydration (6.1%). R0 surgical resection was achieved in 5 patients (15.2%) after CRT. Median OS was 22.0 months (91% at 1 year and 45% at 2 years). Median DMFS was 17.8 months (69% at 1 year and 35% at 2 years). LC was 84% at 1 year and 55% at 2 years. CONCLUSIONS: OS is promising with the use of FX in BRPC and LAPC, and consolidative CRT was well tolerated in this cohort. Therefore, the role of radiation after multi-agent chemotherapy should be further evaluated in prospective trials.

Spatiotemporal segregation of human marginal zone and memory B cell populations in lymphoid tissue.

Human memory B cells and marginal zone (MZ) B cells share common features such as the expression of CD27 and somatic mutations in their IGHV and BCL6 genes, but the relationship between them is controversial. Here, we show phenotypic progression within lymphoid tissues as MZ B cells emerge from the mature naïve B cell pool via a precursor CD27-CD45RBMEM55+ population distant from memory cells. By imaging mass cytometry, we find that MZ B cells and memory B cells occupy different microanatomical niches in organised gut lymphoid tissues. Both populations disseminate widely between distant lymphoid tissues and blood, and both diversify their IGHV repertoire in gut germinal centres (GC), but nevertheless remain largely clonally separate. MZ B cells are therefore not developmentally contiguous with or analogous to classical memory B cells despite their shared ability to transit through GC, where somatic mutations are acquired.

A Long-Term Survivor of Metastatic Pancreatic Adenocarcinoma: Free of Recurrence 12 Years After Treatment of Oligometastatic Disease.

Aggressive local therapy for patients with oligometastatic pancreatic ductal adenocarcinoma (PDAC) has traditionally not been pursued due to high rates of distant progression. We describe a 62-year-old male initially presenting with resectable PDAC who underwent the Whipple procedure but developed multiple liver metastases within two months of starting adjuvant gemcitabine. Oxaliplatin was added to the regimen and complete resolution of the liver lesions resulted. He remained disease-free for five years until re-staging revealed a small lung nodule. This was resected and confirmed to be metastatic PDAC. After additional adjuvant gemcitabine, the patient remained free of recurrence for 12 years after diagnosis of metastatic disease and ultimately passed away from complications of ascending cholangitis associated with stricture at the biliary-enteric anastomosis site. He had no evidence of disease recurrence at the time of death. Next-generation sequencing of the tumor was unrevealing, showing only an activating mutation of KRAS and a deleterious mutation of tumor protein p53 (TP53). Our case suggests that while the prognosis for metastatic PDAC is poor, the population is nonetheless heterogeneous. Prognostic biomarkers are needed for the identification of patients for whom aggressive local treatment of oligometastatic PDAC may be warranted.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions.

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response.

Transitional B Cells in Early Human B Cell Development - Time to Revisit the Paradigm?

The B cell repertoire is generated in the adult bone marrow by an ordered series of gene rearrangement processes that result in massive diversity of immunoglobulin (Ig) genes and consequently an equally large number of potential specificities for antigen. As the process is essentially random, the cells exhibiting excess reactivity with self-antigens are generated and need to be removed from the repertoire before the cells are fully mature. Some of the cells are deleted, and some will undergo receptor editing to see if changing the light chain can rescue an autoreactive antibody. As a consequence, the binding properties of the B cell receptor are changed as development progresses through pre-B ≫ immature ≫ transitional ≫ naïve phenotypes. Using long-read, high-throughput, sequencing we have produced a unique set of sequences from these four cell types in human bone marrow and matched peripheral blood, and our results describe the effects of tolerance selection on the B cell repertoire at the Ig gene level. Most strong effects of selection are seen within the heavy chain repertoire and can be seen both in gene usage and in CDRH3 characteristics. Age-related changes are small, and only the size of the CDRH3 shows constant and significant change in these data. The paucity of significant changes in either kappa or lambda light chain repertoires implies that either the heavy chain has more influence over autoreactivity than light chain and/or that switching between kappa and lambda light chains, as opposed to switching within the light chain loci, may effect a more successful autoreactive rescue by receptor editing. Our results show that the transitional cell population contains cells other than those that are part of the pre-B ≫ immature ≫ transitional ≫ naïve development pathway, since the population often shows a repertoire that is outside the trajectory of gene loss/gain between pre-B and naïve stages.

Prognostic significance of cyclooxygenase-2 in oropharyngeal squamous cell carcinoma.

PURPOSE: To determine the relative prognostic significance of cyclooxygenase (COX)-2 expression in patients with oropharyngeal squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN: This retrospective cohort study included 82 patients with SCC referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Connecticut) between 1980 and 1999 who were treated with primary external beam radiotherapy or gross total surgical resection and postoperative radiotherapy. A microarray of archival tumor tissue was constructed and stained with monoclonal antibodies directed against COX-2 and scored for intensity by a pathologist blinded to the clinical outcomes of the patients. COX-2 immunoreactivity and clinicopathological data were analyzed with respect to survival endpoints using bivariate and multivariate techniques. RESULTS: Frequency of COX-2 overexpression was 45%. In multivariate analysis, COX-2 positivity predicted poor 3-year survival (P = 0.02; odds ratio = 0.41; 95% confidence interval, 0.20-0.84). Increasing age was significantly associated with increased 3-year survival (P = 0.03; odds ratio = 1.04; 95% confidence interval, 1.004-1.09). Positive COX-2 status trended toward predicting decreased 3-year disease-free survival. CONCLUSIONS: COX-2 was the most important predictor of poor survival in this patient cohort. In patients with oropharyngeal SCC treated with external-beam radiation therapy, overexpression of COX-2 may affect clinical outcome, and COX-2 may therefore prove valuable both as a prognostic factor and as a therapeutic target.

Capecitabine as a Radiosensitizer in Adjuvant Chemoradiotherapy for Pancreatic Cancer: A Retrospective Study.

AIM: Pancreatic cancer remains one of the deadliest cancer diagnoses and is the fourth leading cause of cancer-related deaths in the U.S. Surgery is the mainstay of treatment for the 20% for whom the tumor is resectable, however, controversy exists over the appropriate adjuvant therapy where local recurrence rates remain strikingly high (50-85%). We aimed to evaluate the safety and efficacy of adding capecitabine (a known radiosensitizer by direct and abscopal effects) to concurrent radiation in the adjuvant setting after resection of pancreatic adenocarcinoma. PATIENTS AND METHODS: We conducted a retrospective study of 63 patients diagnosed from 2004-2013 with histopathologically-confirmed stage I/II pancreatic cancer treated with a surgical resection followed by adjuvant concurrent chemoradiation to at least 45 Gy using 3D planning and capecitabine at 1,600 mg/m(2)/day (Monday-Friday) for 6 weeks. This was combined with either 4 months of gemcitabine at 1,000 mg/m(2) weekly for 3 out of 4 weeks or capecitabine at 2,000 mg/m(2) for 14 days every 3 weeks for a total of 4 months. RESULTS: The majority of patients were over 65 years old (71%), male (60%), had negative surgical margins (79%), had pancreatic head or neck involvement (71%), Eastern Cooperative Oncology Group performance score of 1 (71%), and a cancer antigen 19-9 in the range of 11-100 U/ml at the time of diagnosis (51%). Of the 63 patients reviewed, 61 patients (97%) completed concurrent chemoradiotherapy. Treatment was halted in one patient due to gastritis and a second for gastrointestinal bleeding. Otherwise, adverse reactions during concurrent chemoradiotherapy were well-tolerated and the majority were Common Terminology Criteria for Adverse Events grades 1 and 2. Grade 3 toxicity was anorexia (n=2) and hand and foot syndrome (n=2) and GI bleeding (n=1). The only grade 4 toxicities were anorexia (n=1) and fatigue (n=1). The median follow-up of patients at the time of analysis was 36 months. The median survival of the entire cohort was 23.5 (range=8.5-42) months. The 1-, 2- and 3-year survival rates were 80%, 35% and 25%, respectively. CONCLUSION: Concurrent chemoradiation using capecitabine as a radiosensitizer in the adjuvant setting for pancreatic cancer was completed by the vast majority of patients in this series. Treatment was relatively well-tolerated, and its efficacy seems comparable to that for historical controls. This study probably represents the largest yet reported using capecitabine in this setting. Future studies including an increased sample size are required.