Full-length IL-33 augments pulmonary fibrosis in an ST2- and Th2-independent, non-transcriptomic fashion.

Mature IL-33 (MIL33) acting through its receptor, ST2, is known to regulate fibrosis. The precursor, full-length IL-33 (FLIL33), may function differently from MIL33 and independently of ST2. Here we report that genetic deletion of either IL-33 or ST2 attenuates pulmonary fibrosis in the bleomycin model, as does Cre-induced IL-33 deficiency in response to either acute or chronic bleomycin challenge. However, adenovirus-mediated gene delivery of FLIL33, but not MIL33, to the lungs of either wild-type or ST2-deficient mice potentiates the profibrotic effect of bleomycin without inducing a Th2 phenotype. In cultured mouse lung cells, FLIL33 overexpression induces moderate and distinct transcriptomic changes compared with a robust response induced by MIL33, whereas ST2 deletion abrogates the effects of both IL-33 forms. Thus, FLIL33 may contribute to fibrosis in an ST2-independent, Th2-independent, non-transcriptomic fashion, suggesting that pharmacological targeting of both FLIL33 and MIL33 may prove efficacious in patients with pulmonary fibrosis.

Cryptococcal empyema treated with tube thoracostomy and intrapleural fibrinolysis.

A 55-year old woman with a history of relapsed T-cell ALL presented with right pleuritic chest pain and decreased breath sounds over the right hemithorax. Imaging of the chest showed loculated effusions. Tube thoracostomy was performed with intrapleural application of alteplase and dornase alpha over a 3-day period. Repeat imaging demonstrated a marked decrease in the volume of the effusion. In most prior published cases of pleural cryptococcosis, surgical drainage was required in addition to prolonged antifungal agents. More than 50% of patients with cryptococcal infection have severe underlying disease or immunodeficiency state making them high risk for surgery. This is the first case to our knowledge of cryptococcal empyema successfully treated with tube thoracostomy and intrapleural fibrinolysis.

Acute eosinophilic pneumonia triggered by secondhand cigarette smoke exposure in an elderly man.

The spectrum of eosinophilic lung diseases comprises a diverse group of pulmonary disorders associated with tissue or peripheral eosinophilia. [Acute eosinophilic pneumonia (AEP)] is an uncommon eosinophilic lung disease that can be idiopathic, but identifiable causes include medications, inhalational exposures and infections. Most cases in the literature are associated with first-time cigarette smoking or resuming smoking. Herein, we present a case of AEP in an elderly man triggered by exposure to secondhand tobacco smoke, in whom a transbronchial biopsy was diagnostic. The patient recovered fully with glucocorticoid therapy without recurrence after avoiding further secondhand smoke.

IFN-γ directly controls IL-33 protein level through a STAT1- and LMP2-dependent mechanism.

IL-33 contributes to disease processes in association with Th1 and Th2 phenotypes. IL-33 mRNA is rapidly regulated, but the fate of synthesized IL-33 protein is unknown. To understand the interplay among IL-33, IFN-γ, and IL-4 proteins, recombinant replication-deficient adenoviruses were produced and used for dual expression of IL-33 and IFN-γ or IL-33 and IL-4. The effects of such dual gene delivery were compared with the effects of similar expression of each of these cytokines alone. In lung fibroblast culture, co-expression of IL-33 and IFN-γ resulted in suppression of the levels of both proteins, whereas co-expression of IL-33 and IL-4 led to mutual elevation. In vivo, co-expression of IL-33 and IFN-γ in the lungs led to attenuation of IL-33 protein levels. Purified IFN-γ also attenuated IL-33 protein in fibroblast culture, suggesting that IFN-γ controls IL-33 protein degradation. Specific inhibition of caspase-1, -3, and -8 had minimal effect on IFN-γ-driven IL-33 protein down-regulation. Pharmacological inhibition, siRNA-mediated silencing, or gene deficiency of STAT1 potently up-regulated IL-33 protein expression levels and attenuated the down-regulating effect of IFN-γ on IL-33. Stimulation with IFN-γ strongly elevated the levels of the LMP2 proteasome subunit, known for its role in IFN-γ-regulated antigen processing. siRNA-mediated silencing of LMP2 expression abrogated the effect of IFN-γ on IL-33. Thus, IFN-γ, IL-4, and IL-33 are engaged in a complex interplay. The down-regulation of IL-33 protein levels by IFN-γ in pulmonary fibroblasts and in the lungs in vivo occurs through STAT1 and non-canonical use of the LMP2 proteasome subunit in a caspase-independent fashion.

Full-length IL-33 promotes inflammation but not Th2 response in vivo in an ST2-independent fashion.

Expression of IL-33 is elevated in patients with pulmonary diseases, and full-length (not proteolytically processed) IL-33 is the predominant form in the lungs in health and disease. To determine whether activation of IL-33 is needed for functional effects, activities of full-length mouse and mature mouse (mm) forms of IL-33 were compared in vivo. Replication-deficient adenoviral constructs were used for gene delivery. Both isoforms caused pulmonary infiltration of lymphocytes and neutrophils, whereas mm IL-33 also caused pulmonary eosinophilia and goblet cell hyperplasia and increased expression of IL-4, IL-5, IL-13, IL-17, MCP-1, and KC. The different effects were not associated with differential release from IL-33-producing cells or by differences in subcellular distributions of IL-33 isoforms. Germline deficiency of the cell surface receptor chain ST2 abrogated the mm IL-33-induced Th2-associated effects (pulmonary eosinophilia, goblet cell hyperplasia, and increased IL-4 and IL-5), yet the lymphocytic infiltration induced by full-length mouse IL-33 or mm IL-33 was not fully abrogated by the absence of ST2. The similar effects of IL-33 isoforms were associated with comparable regulation of gene expression, notably matrix metalloproteinases 3, 10, and 13. Thus, full-length IL-33 is functionally active in vivo in an ST2-independent fashion, and its effects are partially different from those of mature IL-33. The different effects of these isoforms, particularly the pro-Th2 effects of mature IL-33, are due to differential utilization of the IL-33R chain ST2, whereas their similar effects result from regulation of gene expression.

Genomic profiling of tissue and blood predicts survival outcomes in patients with resected pleural mesothelioma.

PURPOSE: Pleural mesothelioma (PM) is an aggressive tumor still considered incurable, in part due to the lack of predictive biomarkers. Little is known about the clinical implications of molecular alterations in resectable PM tissues and blood. Here, we characterized genetic alterations to identify prognostic and predictive biomarkers in patients with resected PM. EXPERIMENTAL DESIGN: Targeted next-generation sequencing was performed in retrospective pleural tumor tissue and paired plasma samples from stage IB-IIIB resected PM. Association between prognosis and presence of specific mutations was validated in silico. RESULTS: Thirty PM tissues and paired blood samples from 12 patients were analyzed. High tissue tumor mutational burden (TMB) (>10 mutations/Mb), tissue median minor allele frequency (MAF) (>9 mutations/Mb), and blood TMB (>6 mutations/Mb), tissue KMT2C, PBRM1, PKHD1,EPHB1 and blood LIFR mutations correlated with longer disease-free survival and/or overall survival. High concordance (>80%) between tissue and blood was found for some mutations. CONCLUSIONS: Tissue TMB and MAF, blood TMB, and specific mutations correlated with outcomes in patients with resected PM and should be further studied to validate their role as prognostic biomarkers and potentially predictive factors for combinations with immune-checkpoint inhibitors. This suggest that molecular profiling could identify longer survivors in patients with resected PM.

Prophylactic epinephrine attenuates severe bleeding in lung transplantation patients undergoing transbronchial lung biopsy: Results of the PROPHET randomized trial.

BACKGROUND: Severe hemorrhage is an uncommon yet potentially life-threatening complication of transbronchial lung biopsy. Lung transplantation recipients undergo multiple bronchoscopies with biopsy and are considered to be at an increased risk for bleeding from transbronchial biopsy, independent of traditional risk factors. We aimed to evaluate the efficacy and safety of endobronchial administration of prophylactic topical epinephrine in attenuating transbronchial biopsy-related hemorrhage in lung transplant recipients. METHODS: The Prophylactic Epinephrine for the Prevention of Transbronchial Lung Biopsy-related Bleeding in Lung Transplant Recipients study was a 2-center, randomized, double blind, placebo-controlled clinical trial. Participants undergoing transbronchial lung biopsy were randomized to receive 1:10,000-diluted topical epinephrine vs saline placebo administered prophylactically into the target segmental airway. Bleeding was graded based on a clinical severity scale. The primary efficacy outcome was incidence of severe or very severe hemorrhage. The primary safety outcome was a composite of 3-hours all-cause mortality and an acute cardiovascular event. RESULTS: A total of 66 lung transplantation recipients underwent 100 bronchoscopies during the study period. The primary outcome of severe or very severe hemorrhage occurred in 4 cases (8%) in the prophylactic epinephrine group and in 13 cases (24%) in the control group (p = 0.04). The composite primary safety outcome did not occur in any of the study groups. CONCLUSIONS: In lung transplantation recipients undergoing transbronchial lung biopsy, prophylactic administration of 1:10,000-diluted topical epinephrine into the target segmental airway before biopsy attenuates the incidence of significant endobronchial hemorrhage without conveying a significant cardiovascular risk. (ClinicalTrials.gov identifier: NCT03126968).

Natural production and functional effects of alternatively spliced interleukin-4 protein in asthma.

We have previously described an alternatively spliced isoform of IL-4 mRNA that omits exon 2 and is termed IL-4δ2. However, the natural production of IL-4δ2 protein and its association with disease have not been previously assessed due to unavailability of an antibody that interacts with IL-4δ2 without cross-reactivity with full length IL-4. We used a unique monoclonal antibody (mAb) that reacts with IL-4δ2, but not with IL-4, and observed that IL-4δ2 is naturally produced by T cells from patients with asthma, but not from healthy controls. The kinetics of IL-4δ2 and IL-4 production by phorbol myristate acetate (PMA)/ionomycin-activated cells differed, with IL-4δ2 increasing at 48-72h and IL-4 peaking at 24h. The steady-state levels of IL-4δ2 mRNA varied significantly among the donors and were discordant with the corresponding protein levels, suggesting post-transcriptional regulation of protein production. Polarized Th1 or Th2 lymphocytes were not a major source of IL-4δ2. Stimulation of cultured T lymphocytes with IL-4δ2 caused elevated production of IFN-γ, IL-10, IL-6, MCP-1, and TNF-α, with notable differences between patients and controls in the production of IFN-γ, IL-10, and IL-6. Thus, IL-4δ2 is natively produced not only as mRNA but also as a protein by cells other than Th1 or Th2. It is regulated post-transcriptionally, is associated with allergic asthma, and regulates production of other cytokines by primary T lymphocytes. Alternatively spliced interleukin-4 may be a new biomarker, a pathophysiological player, and possibly a molecular target for future therapies in asthma.

Bleeding Risk With Combination Intrapleural Fibrinolytic and Enzyme Therapy in Pleural Infection: An International, Multicenter, Retrospective Cohort Study.

BACKGROUND: Combination intrapleural fibrinolytic and enzyme therapy (IET) has been established as a therapeutic option in pleural infection. Despite demonstrated efficacy, studies specifically designed and adequately powered to address complications are sparse. The safety profile, the effects of concurrent therapeutic anticoagulation, and the nature and extent of nonbleeding complications remain poorly defined. RESEARCH QUESTION: What is the bleeding complication risk associated with IET use in pleural infection? STUDY DESIGN AND METHODS: This was a multicenter, retrospective observational study conducted in 24 centers across the United States and the United Kingdom. Protocolized data collection for 1,851 patients treated with at least one dose of combination IET for pleural infection between January 2012 and May 2019 was undertaken. The primary outcome was the overall incidence of pleural bleeding defined using pre hoc criteria. RESULTS: Overall, pleural bleeding occurred in 76 of 1,833 patients (4.1%; 95% CI, 3.0%-5.0%). Using a half-dose regimen (tissue plasminogen activator, 5 mg) did not change this risk significantly (6/172 [3.5%]; P = .68). Therapeutic anticoagulation alongside IET was associated with increased bleeding rates (19/197 [9.6%]) compared with temporarily withholding anticoagulation before administration of IET (3/118 [2.6%]; P = .017). As well as systemic anticoagulation, increasing RAPID score, elevated serum urea, and platelets of < 100 × 109/L were associated with a significant increase in bleeding risk. However, only RAPID score and use of systemic anticoagulation were independently predictive. Apart from pain, non-bleeding complications were rare. INTERPRETATION: IET use in pleural infection confers a low overall bleeding risk. Increased rates of pleural bleeding are associated with concurrent use of anticoagulation but can be mitigated by withholding anticoagulation before IET. Concomitant administration of IET and therapeutic anticoagulation should be avoided. Parameters related to higher IET-related bleeding have been identified that may lead to altered risk thresholds for treatment.

Management of life-threatening hemoptysis in the ICU.

Life-threatening hemoptysis is commonly encountered in the ICU and its management can be challenging even for experienced clinicians. Depending on the etiology and severity, one can tailor the treatment modality and therapeutic intervention(s). The grading of severity of hemoptysis varies greatly in the literature; however, unlike hemorrhage in other scenarios, small amounts of blood can significantly impair oxygenation and ventilation leading to cardiovascular collapse. Importantly, the initial evaluation and management should focus on airway and hemodynamic stabilization along with maintenance of oxygenation and ventilation. In this review, we discuss commonly encountered etiologies, vascular anatomy, diagnostic evaluation, and therapeutic interventions. We examine the evolving trends in etiologies of life-threating hemoptysis over the years. The role of flexible and rigid bronchoscopy as both a diagnostic and therapeutic modality is explored, as well as the use and indications of several bronchoscopic techniques, such as topical hemostatic agents, endobronchial tamponade, and tranexamic acid (TXA). In addition, we assess the use of multi-row detector computed tomography as the initial rapid diagnostic method of choice and its use in planning for definitive treatment. The efficacy and long-term results of bronchial artery embolization (BAE) are evaluated, as well as indications for surgical intervention. Furthermore, the importance of a multidisciplinary approach is emphasized. The necessary interplay between intensivists, consultative services, and radiologists is described in detail and an algorithmic management strategy incorporating the above is outlined. Given the complexity in management of life-threatening hemoptysis, this paper aims to summarize the available diagnostic and therapeutic methods and provide a standardized approach for the management of patients with this often difficult to treat condition.

State of the art: percutaneous tracheostomy in the intensive care unit.

Percutaneous tracheostomy is a commonly performed procedure for patients in the intensive care unit (ICU) and offers many benefits, including decreasing ICU length of stay and need for sedation while improving patient comfort, effective communication, and airway clearance. However, there is no consensus on the optimal timing of tracheostomy in ICU patients. Ultrasound (US) and bronchoscopy are useful adjunct tools to optimize procedural performance. US can be used pre-procedurally to identify vascular structures and to select the optimal puncture site, intra-procedurally to assist with accurate placement of the introducer needle, and post-procedurally to evaluate for a pneumothorax. Bronchoscopy provides real-time visual guidance from within the tracheal lumen and can reduce complications, such as paratracheal puncture and injury to the posterior tracheal wall. A step-by-step detailed procedural guide, including preparation and procedural technique, is provided with a team-based approach. Technical aspects, such as recommended equipment and selection of appropriate tracheostomy tube type and size, are discussed. Certain procedural considerations to minimize the risk of complications should be given in circumstances of patient obesity, coagulopathy, or neurologic illness. Herein, we provide a practical state of the art review of percutaneous tracheostomy in ICU patients. Specifically, we will address pre-procedural preparation, procedural technique, and post-tracheostomy management.

Liquid biopsy from research to clinical practice: focus on non-small cell lung cancer.

INTRODUCTION: In the current era of personalized medicine, liquid biopsy has acquired a relevant importance in patient management of advanced stage non-small cell lung cancer (NSCLC). As a matter of fact, liquid biopsy may supplant the problem of inadequate tissue for molecular testing. The term 'liquid biopsy' refers to a number of different biological fluids, but is most clearly associated with plasma-related platforms. It must be taken into account that pre-analytical processing and the selection of the appropriate technology according to the clinical context may condition the results obtained. In addition, novel clinical applications beyond the evaluation of the molecular status of predictive biomarkers are currently under investigation. AREAS COVERED: This review summarizes the available evidence on pre-analytical issues and different clinical applications of liquid biopsies in NSCLC patients. EXPERT OPINION: Liquid biopsy should be considered not only as a valid alternative but as complementary to tissue-based molecular approaches. Careful attention should be paid to the optimization and standardization of all phases of liquid biopsy samples management in order to determine a significant improvement in either sensitivity or specificity, while significant reducing the number of 'false negative' or 'false positive' molecular results.

Electrocautery Snare Resection and Argon Plasma Coagulation of Endobronchial Kaposi Sarcoma Presenting as an Obstructing Tumor.

Kaposi sarcoma (KS) is the most common neoplasm associated with Acquired Immune Deficiency Syndrome (AIDS), but antiretroviral therapy has reduced its incidence dramatically. Endobronchial KS is usually associated with concurrent mucocutaneous lesions and is highly vascular; so biopsy generally is not recommended. The use of advanced bronchoscopic techniques for evaluation of endobronchial KS may mitigate the bleeding risks but has not been described previously. We describe an unusual case of KS, which presented as an isolated obstructing endobronchial tumor that was effectively resected using electrocautery snare and argon plasma coagulation (APC) during bronchoscopy.

Intrapleural Alteplase and Dornase in a Pregnant Woman With Complicated Parapneumonic Effusion.

The use of intrapleural alteplase and dornase in pregnant patients remains an uncertain practice because bleeding complications in these cases could be devastating. We present a case in which we successfully used a modified protocol safely.

Tissue Acquisition During EBUS-TBNA: Comparison of Cell Blocks Obtained From a 19G Versus 21G Needle.

BACKGROUND: Previous studies have shown that needle gauge size has no significant impact on diagnostic yield during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Our objective was to determine whether cell blocks obtained via the new Flex 19G EBUS-TBNA needle would contain more cellular material based on cell area compared with those obtained from a 21G needle. METHODS: A prospective analysis of patients undergoing EBUS-TBNA at our institutions was performed. Sampling of the same lesion(s) with both the Flex 19G and 21G needles was performed in an alternating manner. In total, 47 patients with suspected lung cancer or mediastinal/hilar lymphadenopathy were included with a total of 83 lesions biopsied. Cell block area was calculated using the Aperio ImageScope software. RESULTS: Mean cell area in the Flex 19G group was 7.34±12.46 mm compared with 5.23±10.73 mm in the 21G group (P=0.02). In the malignant subgroup, the average cell area was 16.16±16.30 mm in the Flex 19G group versus 11.09±15.55 mm in the 21G group (P=0.02). No significant difference was noted in the mean cell area within the nonmalignant subgroup, 1.80±3.01 mm in the 19G group versus 1.56±1.79 mm in the 21G group (P=0.60). CONCLUSION: The cell area obtained via the 19G needle was significantly larger than that obtained with the 21G needle. Further multicenter randomized studies are needed to identify the utility of the Flex 19G needle in diagnosing/subtyping lymphoproliferative disorders and adequacy for molecular testing in non-small cell lung cancer.

Prophylactic epinephrine for the prevention of transbronchial lung biopsy-related bleeding in lung transplant recipients (PROPHET) study: a protocol for a multicentre randomised, double-blind, placebo-controlled trial.

INTRODUCTION: Transbronchial lung biopsy (TBLB) is frequently performed in single-lung and double-lung transplant recipients for evaluation of clinical and radiological findings as well as routine surveillance for acute cellular rejection. While rates of clinically significant TBLB-related haemorrhage are <1% for all comers, the incidence in lung transplant recipients is reported to be higher, presumably due to persistent allograft inflammation and alterations in allograft blood flow. While routinely performed by some bronchoscopists, the efficacy and safety profile of prophylactic administration of topical intrabronchial diluted epinephrine for the prevention of TBLB-related haemorrhage has not been explored in a prospective manner. METHODS AND ANALYSIS: In this randomised, double-blind, placebo-controlled multicentre trial (PROPHET Study), single-lung and double-lung transplant adult recipients from participating institutions who are scheduled for bronchoscopy with TBLB for clinical indications will be identified. Potential participants who meet inclusion and exclusion criteria and sign an informed consent will be randomised to receive either diluted epinephrine or placebo prior to performance of TBLB. The degree of TBLB-related haemorrhage will be graded by the performing bronchoscopist as well as independent observers. The primary analysis will compare the rates of severe and very severe bleeding in participants treated with epinephrine or placebo. The study will also evaluate the safety profile of prophylactic topical epinephrine including the occurrence of serious cardiovascular and haemodynamic adverse events. Additional secondary outcomes to be explored include rates of non-severe TBLB-related haemorrhage, overall yield of the bronchoscopic procedure and non-serious cardiovascular and haemodynamic adverse effects. ETHICS AND DISSEMINATION: The study procedures were reviewed and approved by institutional review boards in participating institutions. This study is being externally monitored, and a data and safety monitoring committee has been assembled to monitor patient safety and to evaluate the efficacy of the intervention. The results of this study will be published in peer-reviewed scientific journals and presented at relevant academic conferences. TRIAL REGISTRATION NUMBER: NCT03126968; Pre-results.

Intrapleural Therapy for Empyema in the Setting of a Bronchopleural Fistula: A Novel Use of an Intrabronchial Valve.

Postsurgical empyema with bronchopleural fistula can be difficult to manage. We present a patient with postoperative empyema with bronchopleural fistula who was successfully treated nonoperatively by placing an intrabronchial valve to address the bronchopleural fistula, which allowed for safe administration of intrapleural fibrinolytics and antibiotics for definitive treatment of the empyema. Although the presence of a bronchopleural fistula is considered a contraindication to the administration of intrapleural tissue plasminogen activator and deoxyribonuclease, this case demonstrates a novel use of the intrabronchial valve that allowed these medications to be used.

Implications of Pathologic Complete Response Beyond Mediastinal Nodal Clearance With High-Dose Neoadjuvant Chemoradiation Therapy in Locally Advanced, Non-Small Cell Lung Cancer.

PURPOSE: To determine, in a retrospective analysis of a large cohort of stage III non-small cell lung cancer patients treated with curative intent at our institution, whether having a pathologic complete response (pCR) influenced overall survival (OS) or freedom from recurrence (FFR) in patients who underwent definitive (≥60 Gy) neoadjuvant doses of chemoradiation (CRT). METHODS AND MATERIALS: At our institution, 355 patients with locally advanced non-small cell lung cancer were treated with curative intent with definitive CRT (January 2000-December 2013), of whom 111 underwent mediastinal reassessment for possible surgical resection. Ultimately 88 patients received trimodality therapy. Chi-squared analysis was used to compare categorical variables. The Kaplan-Meier analysis was performed to estimate OS and FFR, with Cox regression used to determine the absolute hazards. RESULTS: Using high-dose neoadjuvant CRT, we observed a mediastinal nodal clearance (MNC) rate of 74% (82 of 111 patients) and pCR rate of 48% (37 of 77 patients). With a median follow-up of 34.2 months (range, 3-177 months), MNC resulted in improved OS and FFR on both univariate (OS: hazard ratio [HR] 0.455, 95% confidence interval [CI] 0.272-0.763, P = .004; FFR: HR 0.426, 95% CI 0.250-0.726, P = .002) and multivariate analysis (OS: HR 0.460, 95% CI 0.239-0.699, P = .001; FFR: HR 0.455, 95% CI 0.266-0.778, P = .004). However, pCR did not independently impact OS (P = .918) or FFR (P = .474). CONCLUSIONS: Mediastinal nodal clearance after CRT continues to be predictive of improved survival for patients undergoing trimodality therapy. However, a pCR at both the primary and mediastinum did not further improve survival outcomes. Future therapies should focus on improving MNC to encourage more frequent use of surgery and might justify use of preoperative CRT over chemotherapy alone.

A novel assay for monitoring internalization of nanocarrier coupled antibodies.

BACKGROUND: Discovery of tumor-selective antibodies or antibody fragments is a promising approach for delivering therapeutic agents to antigen over-expressing cancers. Therefore it is important to develop methods for the identification of target- and function specific antibodies for effective drug delivery. Here we describe a highly selective and sensitive method for characterizing the internalizing potential of multivalently displayed antibodies or ligands conjugated to liposomes into tumor cells. The assay requires minute amounts of histidine-tagged ligand and relies on the non-covalent coupling of these antibodies to fluorescent liposomes containing a metal ion-chelating lipid. Following incubation of cells with antibody-conjugated liposomes, surface bound liposomes are gently removed and the remaining internalized liposomes are quantitated based on fluorescence in a high throughput manner. We have termed this methodology "Chelated Ligand Internalization Assay", or CLIA. RESULTS: The specificity of the assay was demonstrated with different antibodies to the ErbB-2 and EGF receptors. Antibody-uptake correlated with receptor expression levels in tumor cell lines with a range of receptor expression. Furthermore, Ni-NTA liposomes containing doxorubicin were used to screen for the ability of antibodies to confer target-specific cytotoxicity. Using an anti-ErbB2 single chain Fv (scFv) (F5) antibody, cytotoxicity could be conferred to ErbB2-overexpressing cells; however, a poly(ethylene glycol)-linked lipid (DSPE-PEG-NTA-Ni) was necessary to allow for efficient loading of the drug and to reduce nonspecific drug leakage during the course of the assay. CONCLUSION: The CLIA method we describe here represents a rapid, sensitive and robust assay for the identification and characterization of tumor-specific antibodies capable of high drug-delivery efficiency when conjugated to liposomal nanocarriers.