Potential Dosimetric Predictors of Patient-Reported Quality of Life for Head and Neck Cancer Following Chemoradiation IMRT

PURPOSE/OBJECTIVE(S)

This study aims to identify both acute and late patient patient-reported salivary quality of life outcomes in patients with head and neck cancer treated with chemoradiation therapy on a prospective trial.

MATERIALS/METHODS

A cohort of 40 patients with head and neck cancers were included in the study. All patients underwent concurrent chemoradiation therapy using IMRT delivery (1 patient on one Linac, 24 patients on a different Linac, and 15 on a helical delivery machine). All patients were asked to complete the University of Washington Quality of Life (UOW-QOL) questionnaire at baseline, immediately after treatment, as well as at 1 month, 3 months, 6 months, 12 month and 18 months post-treatment. For the salivary quality of life (QOL) outcome scores, the possible responses were scored on a discreet scale of 100, 70, 30, and 0, with 100 as normal and 0 as dysfunctional. Dosimetric endpoints achieved based on the treatment plan, such as maximum/mean/minimum doses, V30 (percent volume receiving 30 Gy dose), and Dy (dose received to y percent volume) were collected for the bilateral salivary glands, bilateral temporomandibular joint and bilateral submandibular glands. The associations between these dosimetric parameters and the corresponding salivary QOL scores at each time point were analyzed. A Wilcoxon test was performed to identify any differences in the dosimetry and salivary QOL scores among the four different responses.

RESULTS

At short-term follow-up including 1- and 6-month, the distribution of the mean dose received by the right parotid was significantly different between the patients that reported a salivary QOL score of 30 and those that reported 100, with p-values of 0.007 for the 1-month comparison and 0.006 for the 6-month comparison. This was also seen for the V30, with p-values of 0.027 for the 1-month comparison and 0.013 for the 6-month comparison. At 3 months, the maximum dose received by the left temporomandibular joint was significantly different between the patients that reported 30 and those that reported 70, with a p-value of 0.038. At 6 months, the average dose distribution of the right submandibular gland received between the patients that reported a score of 30 and 100 was also significantly different, with a p-value of 0.006. At the long-term follow-up time points of 12 and 18 months, no significant differences were found.

CONCLUSION

The significant differences seen in the data suggest that the dosimetry may have effects on patient reported salivary QOL at short-term follow-up but not long-term. This provides a new perspective into how a patient's QOL over a period of time could be affected by the amount of dose to critical organs. These results also serve as the basis for further investigation into the actual delivered dose, which could differ from the planned dose due to daily anatomic changes over the course of head and neck radiotherapy delivery. These daily volumetric and dosimetric changes may guide early adaptive treatment to improve patient-reported QOL outcomes.

Use of Postoperative PET/CT in Altering Management in Adjuvant Head and Neck Radiation Therapy

PURPOSE/OBJECTIVE(S)

Routine clinical practice does not include postoperative positron emission tomography (PET)/CT prior to postoperative radiation therapy (PORT) for head and neck cancer. Besides logistical challenges in obtaining postoperative PET/CT within six weeks after surgery, interpreting PET/CT findings in the postoperative setting can also be difficult. However, given the potential for residual or rapidly recurrent disease, postoperative PET/CT may help identify the need for additional diagnostic evaluation or alter adjuvant therapy. There are limited data evaluating the utility of postoperative PET/CT prior to PORT for head and neck cancer. We sought to evaluate the use and clinical relevance of postoperative PET/CT prior to PORT.

MATERIALS/METHODS

In this retrospective, single-institution cohort study, we identified patients with head and neck cancer between 2013 and 2020 who received a postoperative PET/CT prior to PORT. We extracted electronic medical record data supplemented with manual chart review to collect patient and disease-related information. We measured the rates of additional diagnostic workup and treatment alterations as a result of postoperative PET/CT findings.

RESULTS

The cohort included 29 patients who received a postoperative PET/CT prior to PORT. The mean age at diagnosis was 60.8 years (standard deviation: 15.0 years) and 20 (69.0%) were male. Regarding primary site, 10 (34.5%) were oropharynx, 7 (24.1%) were salivary gland, and 6 (20.7%) were oral cavity. The mean time from surgery to postoperative PET was 40.9 days (standard deviation: 27.7 days), and the mean time from postoperative PET/CT to start of PORT was 22.4 days (standard deviation: 20.3 days). A total of 9 (31.0%) patients experienced a change in management as a result of the PET/CT findings. Six (66.7%) patients received a biopsy. All 9 patients had a change in their radiation treatment plan, either dose escalation, target change, or in one case, converting to palliative dosing. Six (66.7%) patients were recommended addition of chemotherapy as a result of additional workup, with 4 (44.4%) of those patients ultimately receiving chemotherapy. Three (33.3%) patients underwent re-resection prior to PORT.

CONCLUSION

In patients with head and neck cancer who received postoperative PET/CT prior to PORT, a meaningful proportion underwent additional diagnostic evaluation and/or experienced an alteration in adjuvant therapy as a result of the imaging findings. Interestingly, all patients with abnormal postoperative PET findings had changes in their radiation treatment plan, including at least boosting gross disease for patients in whom re-resection or chemotherapy was not pursued. Future work will seek to expand this cohort through 2022 when postoperative PET/CT became more routine at our institution and include oncologic outcomes. Additional studies are needed to identify appropriate candidates for postoperative PET/CT and determine the clinical impact of postoperative PET/CT.

A survival prediction model via interpretable machine learning for patients with oropharyngeal cancer following radiotherapy

PURPOSE

To explore interpretable machine learning (ML) methods, with the hope of adding more prognosis value, for predicting survival for patients with Oropharyngeal-Cancer (OPC).

METHODS

A cohort of 427 OPC patients (Training 341, Test 86) from TCIA database was analyzed. Radiomic features of gross-tumor-volume (GTV) extracted from planning CT using Pyradiomics, and HPV p16 status, etc. patient characteristics were considered as potential predictors. A multi-level dimension reduction algorithm consisting of Least-Absolute-Selection-Operator (Lasso) and Sequential-Floating-Backward-Selection (SFBS) was proposed to effectively remove redundant/irrelevant features. The interpretable model was constructed by quantifying the contribution of each feature to the Extreme-Gradient-Boosting (XGBoost) decision by Shapley-Additive-exPlanations (SHAP) algorithm.

RESULTS

The Lasso-SFBS algorithm proposed in this study finally selected 14 features, and our prediction model achieved an area-under-ROC-curve (AUC) of 0.85 on the test dataset based on this feature set. The ranking of the contribution values calculated by SHAP shows that the top predictors that were most correlated with survival were ECOG performance status, wavelet-LLH_firstorder_Mean, chemotherapy, wavelet-LHL_glcm_InverseVariance, tumor size. Those patients who had chemotherapy, with positive HPV p16 status, and lower ECOG performance status, tended to have higher SHAP scores and longer survival; who had an older age at diagnosis, heavy drinking and smoking pack year history, tended to lower SHAP scores and shorter survival.

CONCLUSION

We demonstrated predictive values of combined patient characteristics and imaging features for the overall survival of OPC patients. The multi-level dimension reduction algorithm can reliably identify the most plausible predictors that are mostly associated with overall survival. The interpretable patient-specific survival prediction model, capturing correlations of each predictor and clinical outcome, was developed to facilitate clinical decision-making for personalized treatment.

A Prospective Phase II Study of Automated Non-Coplanar VMAT for Recurrent Head and Neck Cancer: Initial Report of Feasibility, Safety, and Patient-Reported Outcomes

Simple Summary

The delivery of higher radiation doses has been shown to increase local control, and ultimately survival, for head and neck cancer patients, but highly conformal dose distributions are necessary to minimize normal tissue toxicity. Varian’s HyperArc non-coplanar automated treatment planning and delivery technique has been shown to improve dose conformity for intracranial treatment, but its safety and efficacy for head and neck cancer treatment has yet to be verified. This study evaluates the initial results of a prospective clinical trial using HyperArc for recurrent head and neck cancer patients. We demonstrated that HyperArc can enable significant tumor dose escalation compared to conventional volumetric modulated arc therapy (VMAT) planning while minimizing the dose to organs at risk. Treatment delivery was feasible and safe, with minimal treatment-related toxicities and positive patient-reported quality of life measures.

Abstract

This study reports the initial results for the first 15 patients on a prospective phase II clinical trial exploring the safety, feasibility, and efficacy of the HyperArc technique for recurrent head and neck cancer treatment. Eligible patients were simulated and planned with both conventional VMAT and HyperArc techniques and the plan with superior dosimetry was selected for treatment. Dosimetry, delivery feasibility and safety, treatment-related toxicity, and patient-reported quality of life (QOL) were all evaluated. HyperArc was chosen over conventional VMAT for all 15 patients and enabled statistically significant increases in dose conformity (R50% reduced by 1.2 ± 2.1, p < 0.05) and mean PTV and GTV doses (by 15.7 ± 4.9 Gy, p < 0.01 and 17.1 ± 6.0 Gy, p < 0.01, respectively). The average HyperArc delivery was 2.8 min longer than conventional VMAT (p < 0.01), and the mean intrafraction motion was ≤ 0.5 ± 0.4 mm and ≤0.3 ± 0.1°. With a median follow-up of 12 months, treatment-related toxicity was minimal (only one grade 3 acute toxicity above baseline) and patient-reported QOL metrics were favorable. HyperArc enabled superior dosimetry and significant target dose escalation compared to conventional VMAT planning, and treatment delivery was feasible, safe, and well-tolerated by patients.

Germline biomarkers predict toxicity to anti-PD1/PDL1 checkpoint therapy

BACKGROUND

There is great interest in finding ways to identify patients who will develop toxicity to cancer therapies. This has become especially pressing in the era of immune therapy, where toxicity can be long-lasting and life-altering, and primarily comes in the form of immune-related adverse effects (irAEs). Treatment with the first drugs in this class, anti-programmed death 1 (anti-PD1)/programmed death-ligand 1 (PDL1) checkpoint therapies, results in grade 2 or higher irAEs in up to 25%-30% of patients, which occur most commonly within the first 6 months of treatment and can include arthralgias, rash, pruritus, pneumonitis, diarrhea and/or colitis, hepatitis, and endocrinopathies. We tested the hypothesis that germline microRNA pathway functional variants, known to predict altered systemic stress responses to cancer therapies, would predict irAEs in patients across cancer types.

METHODS

MicroRNA pathway variants were evaluated for an association with grade 2 or higher toxicity using four classifiers on 62 patients with melanoma, and then the panel's performance was validated on 99 patients with other cancer types. Trained classifiers included classification trees, LASSO-regularized logistic regression, boosted trees, and random forests. Final performance measures were reported on the training set using leave-one-out cross validation and validated on held-out samples. The predicted probability of toxicity was evaluated for its association, if any, with response categories to anti-PD1/PDL1 therapy in the melanoma cohort.

RESULTS

A biomarker panel was identified that predicts toxicity with 80% accuracy (F1=0.76, area under the curve (AUC)=0.82) in the melanoma training cohort and 77.6% accuracy (F1=0.621, AUC=0.778) in the pan-cancer validation cohort. In the melanoma cohort, the predictive probability of toxicity was not associated with response categories to anti-PD1/PDL1 therapy (p=0.70). In the same cohort, the most significant biomarker of toxicity in RAC1, predicting a greater than ninefold increased risk of toxicity (p<0.001), was also not associated with response to anti-PD1/PDL1 therapy (p=0.151).

CONCLUSIONS

A germline microRNA-based biomarker signature predicts grade 2 and higher irAEs to anti-PD1/PDL1 therapy, regardless of tumor type, in a pan-cancer manner. These findings represent an important step toward personalizing checkpoint therapy, the use of which is growing rapidly.

Using neural networks to extend cropped medical images for deformable registration among images with differing scan extents

PURPOSE

Missing or discrepant imaging volume is a common challenge in deformable image registration (DIR). To minimize the adverse impact, we train a neural network to synthesize cropped portions of head and neck CT's and then test its use in DIR.

METHODS

Using a training dataset of 409 head and neck CT's, we trained a generative adversarial network to take in a cropped 3D image and output an image with synthesized anatomy in the cropped region. The network used a 3D U-Net generator along with Visual Geometry Group (VGG) deep feature losses. To test our technique, for each of the 53 test volumes, we used Elastix to deformably register combinations of a randomly cropped, full, and synthetically full volume to a single cropped, full, and synthetically full target volume. We additionally tested our method's robustness to crop extent by progressively increasing the amount of cropping, synthesizing the missing anatomy using our network, and then performing the same registration combinations. Registration performance was measured using 95% Hausdorff distance across 16 contours.

RESULTS

We successfully trained a network to synthesize missing anatomy in superiorly and inferiorly cropped images. The network can estimate large regions in an incomplete image, far from the cropping boundary. Registration using our estimated full images was not significantly different from registration using the original full images. The average contour matching error for full image registration was 9.9 mm, whereas our method was 11.6, 12.1, and 13.6 mm for synthesized-to-full, full-to-synthesized, and synthesized-to-synthesized registrations, respectively. In comparison, registration using the cropped images had errors of 31.7 mm and higher. Plotting the registered image contour error as a function of initial preregistered error shows that our method is robust to registration difficulty. Synthesized-to-full registration was statistically independent of cropping extent up to 18.7 cm superiorly cropped. Synthesized-to-synthesized registration was nearly independent, with a -0.04 mm of change in average contour error for every additional millimeter of cropping.

CONCLUSIONS

Different or inadequate in scan extent is a major cause of DIR inaccuracies. We address this challenge by training a neural network to complete cropped 3D images. We show that with image completion, the source of DIR inaccuracy is eliminated, and the method is robust to varying crop extent.

Clinical assessment of geometric distortion for a 0.35T MR-guided radiotherapy system

Purpose

To estimate the overall spatial distortion on clinical patient images for a 0.35 T MR‐guided radiotherapy system.

Methods

Ten patients with head‐and‐neck cancer underwent CT and MR simulations with identical immobilization. The MR images underwent the standard systematic distortion correction post‐processing. The images were rigidly registered and landmark‐based analysis was performed by an anatomical expert. Distortion was quantified using Euclidean distance between each landmark pair and tagged by tissue interface: bone‐tissue, soft tissue, or air‐tissue. For baseline comparisons, an anthropomorphic phantom was imaged and analyzed.

Results

The average spatial discrepancy between CT and MR landmarks was 1.15 ± 1.14 mm for the phantom and 1.46 ± 1.78 mm for patients. The error histogram peaked at 0–1 mm. 66% of the discrepancies were <2 mm and 51% <1 mm. In the patient data, statistically significant differences (p‐values < 0.0001) were found between the different tissue interfaces with averages of 0.88 ± 1.24 mm, 2.01 ± 2.20 mm, and 1.41 ± 1.56 mm for the air/tissue, bone/tissue, and soft tissue, respectively. The distortion generally correlated with the in‐plane radial distance from the image center along the longitudinal axis of the MR.

Conclusion

Spatial distortion remains in the MR images after systematic distortion corrections. Although the average errors were relatively small, large distortions observed at bone/tissue interfaces emphasize the need for quantitative methods for assessing and correcting patient‐specific spatial distortions.

Automated Non-Coplanar VMAT for Dose Escalation in Recurrent Head and Neck Cancer Patients

Simple Summary

The ability to escalate the radiation dose to head and neck tumors has been shown to offer improved local control, and consequently, survival for recurrent head and neck cancer (rHNC) patients. This study evaluates the HyperArc automated non-coplanar planning technique (originally developed for intracranial treatment) for 20 rHNC patients, and compares this technique to conventional planning methods. HyperArc enables significant tumor dose escalation, with average increases in mean target dose of over 11.5 Gy (26%), while maintaining clinically-equivalent doses to nearby organs. Our results show that the average probability of tumor control is 23% higher for HyperArc than conventional techniques.

Abstract

This study evaluates the potential for tumor dose escalation in recurrent head and neck cancer (rHNC) patients with automated non-coplanar volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) planning (HyperArc). Twenty rHNC patients are planned with conventional VMAT SBRT to 40 Gy while minimizing organ-at-risk (OAR) doses. They are then re-planned with the HyperArc technique to match these minimal OAR doses while escalating the target dose as high as possible. Then, we compare the dosimetry, tumor control probability (TCP), and normal tissue complication probability (NTCP) for the two plan types. Our results show that the HyperArc technique significantly increases the mean planning target volume (PTV) and gross tumor volume (GTV) doses by 10.8 ± 4.4 Gy (25%) and 11.5 ± 5.1 Gy (26%) on average, respectively. There are no clinically significant differences in OAR doses, with maximum dose differences of <2 Gy on average. The average TCP is 23% (± 21%) higher for HyperArc than conventional plans, with no significant differences in NTCP for the brainstem, cord, mandible, or larynx. HyperArc can achieve significant tumor dose escalation while maintaining minimal OAR doses in the head and neck—potentially enabling improved local control for rHNC SBRT patients without increased risk of treatment-related toxicities.

Clinical Development and Evaluation of Megavoltage Topogram for Fast Patient Alignment on Helical Tomotherapy

Purpose

To develop and evaluate a fast patient localization tool using megavoltage (MV)-topogram on helical tomotherapy.

Methods and Materials

Eighty-one MV-topogram pairs for 18 pelvis patients undergoing radiation were acquired weekly under an institutional review board–approved clinical trial. The MV-topogram imaging protocol requires 2 orthogonal acquisitions at static gantry angles of 0 degrees and 90 degrees for a programed scan length. A MATLAB based in-house software was developed to reconstruct the MV-topograms offline. Reference images (digitally reconstructed topograms, digitally reconstructed topograms) were generated using the planning computed tomography and tomotherapy geometry. The MV-topogram based alignment was determined by registering the MV-topograms to the digitally reconstructed topogram using bony landmark on commercial MIM software. The daily shifts in 3 translational directions determined from MV-topograms were compared with the megavoltage computed tomography (MVCT) based patient shifts. Linear-regression and two one-sided tests equivalence tests were performed to investigate the relation and equivalence between the 2 techniques. Seventy-eight MV-topogram pairs for 19 head and neck patients were included to validate the finding.

Results

The magnitudes of alignment differences of (MVCT − MV-topogram) (and standard deviations) were −0.3 ± 2.1, −0.8 ± 2.4, and 1.6 ± 1.7 mm for pelvis and 0.6 ± 1.2, 0.8 ± 4.2, 1.6 ± 2.6 mm for head and neck; the linear-regression coefficients between 2 imaging techniques were 1.18, 1.10, 0.94, and 0.86, 0.63, 0.38 in the lateral, longitudinal, vertical directions for pelvis and head and neck, respectively. The acquisition time for a pair of MV-topograms was up to 12.7 times less than MVCT scans (coarse scan mode) while covering longer longitudinal length.

Conclusions

MV-topograms showed equivalent clinical performance to the standard MVCT with significantly less acquisition time for pelvis and H&N patients. The MV-topogram can be used as an alternative or complimentary tool for bony landmark-based patient alignment on tomotherapy.

Analysis of Geometric Performance and Dosimetric Impact of Using Automatic Contour Segmentation for Radiotherapy Planning

Purpose: To analyze geometric discrepancy and dosimetric impact in using contours generated by auto-segmentation (AS) against manually segmented (MS) clinical contours. Methods: A 48-subject prostate atlas was created and another 15 patients were used for testing. Contours were generated using a commercial atlas-based segmentation tool and compared to their clinical MS counterparts. The geometric correlation was evaluated using the Dice similarity coefficient (DSC) and Hausdorff distance (HD). Dosimetric relevance was evaluated for a subset of patients by assessing the DVH differences derived by optimizing plan dose using the AS and MS contours, respectively, and evaluating with respect to each. A paired t-test was employed for statistical comparison. The discrepancy in plan quality with respect to clinical dosimetric endpoints was evaluated. The analysis was repeated for head/neck (HN) with a 31-subject atlas and 15 test cases. Results: Dice agreement between AS and MS differed significantly across structures: from (L:0.92/R: 0.91) for the femoral heads to seminal vesical of 0.38 in the prostate cohort, and from 0.98 for the brain, to 0.36 for the chiasm of the HN group. Despite the geometric disagreement, the paired t-tests showed the lack of statistical evidence for systematic differences in dosimetric plan quality yielded by the AS and MS approach for the prostate cohort. In HN cases, statistically significant differences in dosimetric endpoints were observed in structures with small volumes or elongated shapes such as cord (p = 0.01) and esophagus (p = 0.04). The largest absolute dose difference of 11 Gy was seen in the mean pharynx dose. Conclusion: Varying AS performance among structures suggests a differential approach of using AS on a subset of structures and focus MS on the rest. The discrepancy between geometric and dosimetric-end-point driven evaluation also indicates the clinical utility of AS contours in optimization and evaluating plan quality despite of suboptimal geometrical accuracy.

Head and neck cancer reirradiation with interstitial high-dose-rate brachytherapy

BACKGROUND

As high-dose-rate (HDR) brachytherapy can preferentially spare normal anatomic structures surrounding the radiation target, we report on our experience using this technique in head and neck cancer reirradiation.

METHODS

Twenty patients received HDR brachytherapy reirradiation with curative or palliative intent from 2010-2015. Clinical and toxicity outcomes were recorded. Actuarial outcomes were calculated using Kaplan-Meier analysis.

RESULTS

For curative treatment, actuarial 2-year rates of local control and overall survival (OS) were 73% and 56%, respectively. Palliatively, a 6-month local control rate of 65% was seen. Age >70 years was associated with poorer OS (P = .042). Prior salvage resection showed a trend toward improved local control and OS (P = .069 and P = .063, respectively). Thirty-three percent had grade 3 to 4 late toxicities.

CONCLUSION

Curative-intent HDR brachytherapy reirradiation can provide excellent local control and encouraging OS. Given the late toxicity rates, patient selection is essential, with particular utility for younger patients or those treated with salvage resection.

Systematic Analysis of Clinical Outcomes Following Stereotactic Radiosurgery for Central Neurocytoma

Central neurocytoma (CN) typically presents as an intraventricular mass causing obstructive hydrocephalus. The first line of treatment is surgical resection with adjuvant conventional radiotherapy. Stereotactic radiosurgery (SRS) was proposed as an alternative therapy for CN because of its lower risk profile. The objective of this systematic analysis is to assess the efficacy of SRS for CN. A systematic analysis for CN treated with SRS was conducted in PubMed. Baseline patient characteristics and outcomes data were extracted. Heterogeneity and publication bias were also assessed. Univariate and multivariate linear regressions were used to test for correlations to the primary outcome: local control (LC). The estimated cumulative rate of LC was 92.2% (95% confidence interval: 86.5-95.7%, p<0.001). Mean follow-up time was 62.4 months (range 3-149 months). Heterogeneity and publication bias were insignificant. The univariate linear regression models for both mean tumor volume and mean dose were significantly correlated with improved LC (p<0.001). Our data suggests that SRS may be an effective and safe therapy for CN. However, the rarity of CN still limits the efficacy of a quantitative analysis. Future multi-institutional, randomized trials of CN patients should be considered to further elucidate this therapy.

Eruptive cutaneous squamous cell carcinoma and psoriasis: response to cetuximab

Cutaneous squamous cell carcinomas (CSCCs) comprise 20-30% of nonmelanoma skin cancers (NMSCs), and continue to increase in incidence. We report a case of a patient with severe psoriasis who had recurrent and eruptive CSCCs on her leg, which were successfully treated with cetuximab and radiotherapy. The patient had successful long-term clearance of her skin tumours, with the additional finding of resolution of psoriasis while on cetuximab therapy.

The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors

CD47, a "don't eat me" signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies.

NF-kappaB2 is required for the establishment of central tolerance through an Aire-dependent pathway

NF-kappaB2-deficient mice have impaired T and B cell responses. We found, however, that in these mice there was severe infiltration of lymphocytes into multiple organs and increased activity of autoantibodies to peripheral tissue antigens in a manner similar to that of autoimmune regulator-deficient (Aire-deficient) mice. We further demonstrated that NF-kappaB2 was required for thymic Aire gene transcriptional regulation. The Nfkb2(-/-) thymus had distinct cortical and medullar structures, but reduced Aire and target gene expression of peripheral tissue antigens. Engraftment of Nfkb2(-/-) thymic stroma to nude mice recapitulated the autoimmune phenotype of the native Nfkb2(-/-) mice, confirming a key defect in central tolerance. Lymphotoxin beta receptor (LTbetaR) ligation-induced Aire gene expression was also largely abolished in the absence of NF-kappaB2. Thus NF-kappaB2 downstream of LTbetaR plays an important role in the regulation of central tolerance in an Aire-dependent manner.

Recruitment and activation of naive T cells in the islets by lymphotoxin beta receptor-dependent tertiary lymphoid structure

The development of spontaneous insulin-dependent diabetes mellitus is preceded by the organization of tertiary lymphoid organ (TLO) in situ, but its role in the development of tissue destruction and the cytokines that control such structures have not been fully defined. We have now observed that TNF superfamily 14 (TNFSF14) is upregulated in aged nonobese diabetic (NOD) pancreas with the appearance of TLO. Blockade of TNFSF14 signaling caused a substantial reduction in the expression of lymphotoxin beta receptor (LTbetaR)-controlled migration factors within the islets and disrupts organization of tertiary structures, leading to prevention of diabetes. Consistently, enhancing LTbetaR signaling by transgenic expression of TNFSF14 in the islets of NOD mice rapidly promoted de novo formation of local TLO, resulting in diabetes, even in the absence of draining lymph nodes (LN). Thus, the TNFSF14-LTbetaR pathway appears to be critical in the development and maintenance of TLO for the onset of diabetes.

Lymphotoxin pathway-directed, autoimmune regulator-independent central tolerance to arthritogenic collagen

Ectopic expression of peripherally restricted Ags by medullary thymic epithelial cells (mTECs) is associated with negative selection. Autoimmune regulator (AIRE) is considered to be the master regulator of these Ags. We show in this study that the ectopic expression of type II collagen (CII) in mTECs and the corresponding central tolerance to CII are AIRE independent but lymphotoxin dependent. The failure to properly express CII in mTECs of Lta(-/-) and Ltbr(-/-) mice leads to overt autoimmunity to CII and exquisite susceptibility to arthritis. These findings define the existence of additional pathways of ectopic peripheral Ag expression, parallel to and independent of AIRE, which may cover an extended spectrum of peripheral Ags in the thymus.

A role for lymphotoxin in the acquisition of Ly49 receptors during NK cell development

NK cells lyse tumor, virus-infected and allogeneic cells through a recognition system involving inhibitory and activating receptors, among which are the Ly49 molecules that recognize MHC class I proteins. To date, little is known about the regulation of Ly49 expression during NK cell development. In this study we report that the acquisition of Ly49 receptors by NK cells is significantly reduced in lymphotoxin (LT) alpha-deficient mice, whereas it is increased in LTalpha transgenic mice. Treating normal mice with LTbetaR-Ig fusion protein reduced Ly49 expression, indicating that regulation of Ly49 receptor expression occurs through the engagement of membrane LT to LTbetaR, and not soluble LT to TNFR. In addition, when LTalpha(-/-) mice were treated exogenously with recombinant IL-15, NK cell numbers as well as Ly49 acquisition were restored to wild-type levels. Finally, using real-time PCR analyses of bone marrow cells obtained from LT-deficient or transgenic mice, we show a direct correlation between LTbetaR activation and increased IL-15 transcription. These data suggest that LTbetaR-mediated signals regulate Ly49 expression at least in part through the activation of IL-15.

The human BCL6 transgene promotes the development of lymphomas in the mouse

BCL6, a gene on chromosome 3, band q27, encodes a zinc finger transcriptional repressor that is needed for germinal center formation and has been implicated in the pathogenesis of some human lymphomas when it is mutated or involved in chromosomal rearrangements. To explore further the mechanisms of action of BCL6 in lymphomagenesis, we developed a transgenic mouse model mimicking a common translocation, the t(3, 14)(q27;q32), in human lymphomas. The transgenic mice develop normally and express the transgenic BCL6 protein constitutively in lymphocytes. A small fraction of the animals develop B and T cell lymphomas after a long latency period, but the incidence is dramatically enhanced following administration of N-ethyl-N-nitrosourea, a carcinogen that induces DNA mutations. The N-ethyl-N-nitrosourea-induced lymphomas spread widely, were exclusively T cell, expressed the BCL6 protein, and occurred only in the transgenic mice. Because BCL6 expression has been reported in a number of T cell tumors as well as in the more commonly occurring B cell lymphomas in humans, our transgenic mice provide a model for the study of human lymphomas.

Local expression of B7-H1 promotes organ-specific autoimmunity and transplant rejection

A number of studies have suggested B7-H1, a B7 family member, inhibits T cell responses. Therefore, its expression on nonlymphoid tissues has been proposed to prevent T cell-mediated tissue destruction. To test this hypothesis, we generated transgenic mice that expressed B7-H1 on pancreatic islet beta cells. Surprisingly, we observed accelerated rejection of transplanted allogeneic B7-H1-expressing islet beta cells. Furthermore, transgenic B7-H1 expression broke immune tolerance, as some of the mice spontaneously developed T cell-dependent autoimmune diabetes. In addition, B7-H1 expression increased CD8+ T cell proliferation and promoted autoimmunity induction in a T cell adoptive transfer model of diabetes. Consistent with these findings, B7-H1.Ig fusion protein augmented naive T cell priming both in vitro and in vivo. Our results demonstrate that B7-H1 can provide positive costimulation for naive T cells to promote allograft rejection and autoimmune disease pathogenesis.

Priming of naive T cells inside tumors leads to eradication of established tumors

The tumor barrier comprised of nonantigenic stromal cells may contribute to the failure of tumor rejection. The tumor-necrosis factor superfamily member LIGHT (also known as TNFSF-14) is a ligand of stromal cell-expressed lymphotoxin-beta receptor and T cell-expressed herpes viral entry mediator (HVEM). Here we show that forced expression of LIGHT in the tumor environment induces a massive infiltration of naive T lymphocytes that correlates with an upregulation of both chemokine production and expression of adhesion molecules. Activation of these infiltrating T cells, possibly through HVEM, leads to the rejection of established, highly progressive tumors at local and distal sites. Our study indicates that targeting the tumor barrier may be an effective strategy for cancer immunotherapy.

Lymphotoxin is required for maintaining physiological levels of serum IgE that minimizes Th1-mediated airway inflammation

Although elevated levels of IgE in asthmatic patients are strongly associated with lung infiltration by activated T helper (Th) 2 cells, the physiological role of immunoglobulin E (IgE) in the airway remains largely undefined. Lymphotoxin-deficient α (LTα^−/−) mice exhibit increased airway inflammation, paradoxically accompanied by diminished levels of IgE and reduced airway hyperresponsiveness in response to both environmental and induced antigen challenge. The severe lung inflammation in LTα^−/− mice is Th1 in nature and can be alleviated by IgE reconstitution. Conversely, depletion of IgE in wild-type mice recapitulates the lung pathologies of LTα^−/− mice. Therefore, this work has revealed that lymphotoxin is essential for IgE production, and a physiological role of IgE in the airway may consist of maintaining the balance of Th1 and Th2 responses to prevent aberrant inflammation.

Differential regulation of CCL21 in lymphoid/nonlymphoid tissues for effectively attracting T cells to peripheral tissues

CC chemokine ligand 21 (CCL21)/secondary lymphoid chemokine (SLC), a ligand for CC chemokine receptor 7 (CCR7), has been demonstrated to play a vital role in the homing and localization of immune cells to lymphoid tissues, but its role in nonlymphoid tissues largely remains undefined. Here, we provide evidence that CCL21 in lymphoid and nonlymphoid tissues is differentially regulated by lymphotoxin-dependent (LT-dependent) and -independent mechanisms, respectively. This differential regulation is due to the selective regulation of the CCL21-Ser/CCL21a but not the CCL21-Leu/CCL21b gene by the LT and noncanonical NF-kappaB pathways. This alternate pathway, not dependent on LT or lymphocytes, leading to constitutive expression of CCL21 in nonlymphoid tissues, is critical for the initial recruitment of T lymphocytes to peripheral effector sites. CCL21 expression is subsequently further enhanced in a LT-dependent fashion following airway challenge, potentially facilitating a positive feedback loop to attract additional CCR7+ effector cells. These findings establish an essential role for CCL21 in the recruitment of effector T cells to peripheral tissues and suggest that LT-dependent and -independent regulation of CCL21 plays a role in balancing the central and peripheral immune responses between lymphoid and nonlymphoid tissues.

Lymphotoxin pathway directs thymic Aire expression

The autoimmune regulator Aire is a key mediator of central tolerance for peripherally restricted antigens. Its absence in human patients results in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. The cellular signals that regulate Aire expression are undefined. We show here that lymphotoxin signaling is necessary for the expression of Aire and its downstream target genes. The failure of Aire induction in the thymi of lymphotoxin-deficient and lymphotoxin-beta receptor-deficient mice contributes to overt autoimmunity against self antigens normally protected by Aire. Conversely, stimulation of lymphotoxin-beta receptor by agonistic antibody leads to increased expression of Aire and tissue-restricted antigens in both intact thymi and cultured thymic epithelial cell line. These findings define the essential cross-talk between thymocytes and thymic stroma that is required for central tolerance.

CD4 dependence of gp120IIIB-CXCR4 interaction is cell-type specific

The HIV-1 envelope protein gp120IIIB is selective for the CXCR4 chemokine receptor and has been shown to induce apoptosis in neurons both in vivo and in vitro. We examined the ability of gp120IIIB to signal through the rat CXCR4 (rCXCR4) receptor and its dependence on the presence of the human CD4 (hCD4) protein in a number of cell systems. SDF-1alpha potently inhibited N-type Ca channels in cultured HEK293 cells expressing both the Ca channel subunits and rCXCR4 receptors. However, gp120IIIB was ineffective in producing either Ca channel inhibition or in blocking the effects of SDF-1alpha. However, when hCD4 was coexpressed with rCXCR4 and Ca channel subunits, gp120IIIB also produced Ca channel inhibition. Similarly, in PC12 cells transfected with the rCXCR4, SDF-1alpha produced mobilization of intracellular Ca, while gp120IIIB was only effective when hCD4 was coexpressed. SDF-1alpha induced endocytosis of Yellow Fluorescent Protein (YFP)-tagged rCXCR4 expressed in PC12 cells, as did gp120IIIB, an effect which was enhanced by hCD4 coexpression. When tagged rCXCR4 was expressed in F-11 cells or in rat DRG neurons, SDF-1alpha produced extensive receptor endocytosis. However, the ability of gp120IIIB to produce endocytosis was dependent on the coexpression of hCD4. Our results demonstrate that the degree of hCD4 dependence of the agonist effects of gp120IIIB at the rCXCR4 receptor is cell-type specific.

Signaling via LTbetaR on the lamina propria stromal cells of the gut is required for IgA production

Peyer's patches (PPs) and/or mesenteric lymph nodes (MLNs) are thought to be essential for immunoglobulin A (IgA) production. We found that the severe IgA deficiency in lymphotoxin-deficient (LT(-/-)) mice could be fully reversed by reconstitution with LT-expressing bone marrow, despite the absence of both LNs and PPs. The number of IgA precursors from LT(-/-) mice was not reduced, and they were able to migrate into the lamina propria (LP) of wild-type mice but not of LTbetaR(-/-) mice. Consistently, lymphoid tissue chemokines and adhesion molecules were reduced within the LP of LTalpha(-/-) and LTbetaR(-/-) mice. IgA deficiency in LTalpha(-/-) mice was reversed by the transplantation of a segment of RAG-1 (recombination-activating gene 1) deficient intestine, which confirmed the dispensability of the MLNs and PPs and the sufficiency of the LT-mediated gut microenvironment for IgA production.

B cells control the migration of a subset of dendritic cells into B cell follicles via CXC chemokine ligand 13 in a lymphotoxin-dependent fashion

Certain classes of dendritic cells (DCs) meet rare cognate Ag-specific T and B cells inside primary B cell follicles for the development of germinal centers. However, the mechanisms underlying this coordination are still undefined. Cysteine-rich (CR) domain of the mannose receptor (CR-Fc)(+) DCs are a newly discovered subset of DCs that migrate rapidly into the primary lymphoid follicles from marginal zone after immunization. In this work, we uncover the key role of B cells in the establishment of a microenvironment that allows these DCs to be in the B cell area in a lymphotoxin (LT)-dependent fashion. CR-Fc(+) DCs are absent from the spleens of both LTbetaR- and LTalpha-deficient mice, suggesting that signaling by membrane LT is required for the presence of CR-Fc(+) DCs in the spleen. Interestingly, analysis of mutant mice that lack T, B, or NK cells demonstrates that B cell-derived membrane LT is essential for the unique localization of CR-Fc(+) DCs in the spleen. Using bone marrow transfer and ligand-blocking approaches, we provide evidence that B cell-derived LT acts indirectly on CR-Fc(+) DCs through LTbetaR(+) stromal cells. In analogous fashion to certain Ag-activated T and B cells, CR-Fc(+) DCs, expressing CXCR5, localize to primary lymphoid follicles in response to CXC ligand 13 (B lymphocyte chemoattractant). Together, we propose that B cells play a central role in establishing the chemotactic gradient that attracts not only Ag-activated T and B cells but also Ag-carrying CR-Fc(+) DCs. In turn, CR-Fc(+) DCs and T cells home to B cell follicles to interact with B cells in the developing germinal center.

E1A transformed normal human prostate epithelial cells contain a 16q deletion

The difficulty of maintaining long-term prostate cell cultures has hindered the development of essential models for understanding prostate cancer. We report here the establishment of two 12S E1A transformed non-tumorigenic prostate epithelial cell strains, and their characterization. The two clonal cell strains, TP2 and TP4, proliferated for approximately 40 passages before senescence. Both exhibited a strong dependence on exogenous peptide growth factors and an immunophenotype characteristic of their prostate epithelial origin. Cytogenetic analysis revealed a consistent deletion on the q arm of chromosome 16 in TP2 with an otherwise normal karyotype. Band-specific microdissection generated region-specific probes from 16q23, which when used in fluorescence in situ hybridization (FISH) revealed that the region was deleted in 83% of metaphases analyzed. By cytogenetic analysis and FISH, the q arm of 16 was found deleted from the genome of TP4 in 60% of cells analyzed. Lost sequences on 16q-16q23 in particular--in prostate cancer have been observed by a variety of methods. Localization of common region of deletion has been determined from these studies to be distal to 16q23. Our findings suggest that 16q23 may be of major importance in the development of prostate cancer, and may harbor tumor suppressor elements.

Relationship between newborn and maternal iron status and haematological indices

The haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, haematocrit, serum iron and total iron binding capacity, and serum ferritin concentrations in umbilical cord blood samples taken from 96 appropriate-for-gestational age infants delivered at term were measured and compared to the respective maternal values measured at 36 weeks' gestation. All the values were higher in cord blood. Only maternal mean corpuscular volume and mean corpuscular haemoglobin were correlated with cord serum iron. Cord blood haematological indices were not correlated with either gestation at delivery or birth weight. However, newborn serum ferritin was positively correlated with gestation at delivery, while the maternal:newborn ferritin ratio was inversely correlated with gestation and birth weight. The results suggest that maternal haematological and iron indices are not predictive of the haemoglobin or iron status of the newborn, and that the fetus continues to take up iron from the mother until delivery.

Second-trimester thyroid function and pregnancy outcome in mothers with hyperthyroidism. Birth weight related to mid-trimester triiodothyronine and RBC zinc

Thyroid function at 24-28 weeks gestation was compared between 26 mothers with hyperthyroidism (16 on antithyroid treatment and 10 in remission without treatment) and 15 normal pregnant controls. There was no difference in the total and free thyroxine (TT4 and FT4) or in the total and free triiodothyronine (TT3 and FT3) concentrations, but the erythrocyte zinc (RBC Zn) concentration was significantly lower in the study group (187.3 +/- 46.6 mumol/l RBC versus 223.6 +/- 3.7 mumol/l RBC, p less than 0.01). In the study group, both birth weight and gestation at delivery were significantly correlated with TT3 (r = -0.500, p less than 0.02 and r = -0.460, p less than 0.05, respectively) as well as with RBC Zn (r = 0.473, p less than 0.02 and r = 0.573, p less than 0.01, respectively). The results suggest that plasma concentration of TT3 and of RBC Zn at 24-28 weeks gestation may be helpful prognostic factors in the management of pregnant patients with hyperthyroidism.

The role of transcutaneous electrical nerve stimulation in management of labour in obstetric patients

The study evaluated the effect of transcutaneous electrical nerve stimulation (TENS) in the management of labour. It comprised of 125 subjects with 93 primiparae and 32 multiparae. They were divided into 3 groups. The first group received electrical stimulation from the TENS unit (TENS); the second group (placebo group) had the TENS machine connected but with no current from the TENS unit (TPL); whereas the third group had no machine application (control group). Analgesic requirements, pain assessment, labour duration, Obstetric outcome, and the comments from mother and midwife were analysed. No negative effects on the mothers and babies were reported. Neither was there any objective clinical significant differences demonstrated among the 3 groups.

Plasma and erythrocyte zinc and birth weight in pre-eclamptic pregnancies

Plasma and erythrocyte zinc concentrations in 45 proteinuric pre-eclamptic Chinese women were measured. There was no difference in either the plasma or erythrocyte zinc concentration between pre-eclamptic patients with and without intrauterine growth retardation. There was no correlation between either plasma or erythrocyte zinc concentration with the gestation at delivery, birth weight, mean arterial pressure and plasma albumin concentration. On the other hand, both plasma albumin concentration and mean arterial pressure were significantly correlated to birth weight, and the mean arterial pressure was also significantly higher in patients with intrauterine growth retardation. Plasma and erythrocyte zinc are not useful as indices of severity in pre-eclampsia.

Maternal thyroid hormones and outcome of pre-eclamptic pregnancies

Plasma concentrations of total and free thyroxine (TT4 and FT4), total and free triiodothyronine (TT3 and FT3), thyroid-stimulating hormone (TSH), plasma albumin and urate were measured in 39 proteinuric pre-eclamptic patients presenting before labour. Pre-eclamptic patients had significantly lower FT4 and higher TSH concentrations compared with values in third trimester normotensive pregnancies. There was a significantly higher frequency of lower TT4, TT3 and high TSH levels in the subgroup of pre-eclamptic patients who had low-birthweight babies. Thyroid hormone concentrations were not correlated with gestation at delivery or birthweight but, with the exception of FT4, were correlated with plasma albumin and urate concentrations. Plasma TSH correlated with birthweight and with plasma urate. The results suggest that mild biochemical hypothyroidism may be found in proteinuric pre-eclampsia, and the concentrations of TT4, TT3, FT3 and TSH may reflect the severity of pre-eclampsia.

A longitudinal study of changes in erythrocyte zinc concentration in hyperemesis gravidarum

Erythrocyte zinc concentration and plasma thyroid hormones were measured in 32 patients admitted to hospital because of hyperemesis gravidarum. At presentation, 8 patients had elevated total and free thyroxine concentrations. The initial erythrocyte zinc concentration in these 8 patients was not different from the others, but in 5 of them, a transient drop in the erythrocyte zinc concentration was observed 2-12 weeks later, and which returned to normal towards the end of pregnancy. The lowest erythrocyte zinc concentration in the hyperthyroxinaemic group (171.0 +/- 31.7 mumol/l of RBC) was significantly lower than that of the normothyroxinaemic group (214.2 +/- 33.9 mumol/l of RBC) (p less than 0.01). This indicates that hyperthyroxinaemia in patients with hyperemesis gravidarum represents true hyperthyroidism, but is different from classical thyrotoxicosis in that the elevation of thyroid hormones is transient.

Pregnancy outcome in women with labor-onset hypertension. Similar outcome between labor-onset hypertension and preeclampsia

Labor-onset hypertension is a poorly documented category, and there is scanty information concerning the outcome of pregnancy in this condition. A retrospective study was performed to compare the pregnancy outcome of 36 patients with labor-onset hypertension (group A) with 36 patients with classical preeclampsia diagnosed before labor (group B) who were matched for parity and age. There was no difference in age, past history of hypertensive pregnancies or family history of hypertension between the two groups. The need for intrapartum hypertensive and anticonvulsant treatment as well as the outcome of pregnancy were similar in both groups. The only significant difference was that group A patients had lower maximum and booking systolic and diastolic pressures. The results indicate that labor-onset hypertension represents a late manifestation of the preeclampsia process, because these patients had lower blood pressure in pregnancy and would not be identified until intrapartum elevation of blood pressure satisfied the diagnostic criteria of preeclampsia.

Zinc and birth weight in uncomplicated pregnancies

The relationship between zinc status and birth weight in uncomplicated pregnancies was studied in 59 nulliparous and 27 multiparous Chinese women with singleton pregnancies, delivered at term. Maternal and umbilical cord blood, maternal pubic hair and a segment of the umbilical cord were collected at delivery for analysis. The zinc concentration was significantly higher (p less than 0.0001) in the plasma of newborn infants (13.9 +/- 2.8 mumol/l) than in maternal plasma (9.3 +/- 2.2 mumol/l), while the converse was found in tissue (60.8 +/- 17.0 vs 208.1 +/- 96.2 micrograms/g, p less than 0.0001). There was no significant correlation between birth weight and either maternal or newborn plasma or tissue zinc concentrations. Parity had no significant effect on maternal or newborn zinc concentrations in tissue and plasma.

Antenatal complications and perinatal outcome in patients with nausea and vomiting-complicated pregnancy

The incidence of nausea and vomiting-complicated pregnancy was determined in a district hospital in Hong Kong. Nausea was present in 11.4% and vomiting in 63.5% of pregnant women. Patients with vomiting complicating early pregnancy have a statistically significant higher incidence of antepartum haemorrhage of indeterminate origin. The incidences of medical diseases complicating pregnancy, other major antenatal complications, and the neonatal outcome were not different between vomiting and non-vomiting patients.

Single dose prophylactic antibiotics in caesarean sections

A prospective, double-blind randomized trial was carried out at the Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, involving 4 groups of patients receiving a single intravenous dose of placebo, ampicillin, ampicillin and metronidazole, and ampicillin and sulbactam before operation. No difference in postoperative morbidity was present between the 4 groups of patients.