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Rationale: The lungs are a common site of serious infection in both healthy and immunocompromised subjects, and the most likely route of delivery of a bioterror agent. Since the airway epithelium shows great structural plasticity in response to inflammatory stimuli, we hypothesized it might also show functional plasticity.Objectives: To test the inducibility of lung defenses against bacterial challenge.Methods: Mice were treated with an aerosolized lysate of ultraviolet-killed nontypeable (unencapsulated) Haemophilus influenzae (NTHi), then challenged with a lethal dose of live Streptococcus pneumoniae (Spn) delivered by aerosol.Measurements and Main Results: Treatment with the NTHi lysate induced complete protection against challenge with a lethal dose of Spn if treatment preceded challenge by 4 to 24 hours. Lesser levels of protection occurred at shorter (83% at 2 h) and longer (83% at 48-72 h) intervals between treatment and challenge. There was also some protection when treatment was given 2 hours after challenge (survival increased from 14 to 57%), but not 24 hours after challenge. Protection did not depend on recruited neutrophils or resident mast cells and alveolar macrophages. Protection was specific to the airway route of infection, correlated in magnitude and time with rapid bacterial killing within the lungs, and was associated with increases of multiple antimicrobial polypeptides in lung lining fluid.Conclusions: We infer that protection derives from stimulation of local innate immune mechanisms, and that activated lung epithelium is the most likely cellular effector of this response. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value. [ABSTRACT FROM AUTHOR]

Hobnail papillary thyroid carcinoma (HNPTC) is an unusual and aggressive variant of PTC. Malignant pleural effusion secondary to thyroid carcinoma is a rare event reported in less than 1% of cases. Herein we present a case of metastatic HNPTC initially diagnosed by pleural effusion cytology, with a very poor outcome. A 42-year-old male with no previous cancer history, presented with an anterior neck mass growing for the past year. A computed tomography (CT) scan revealed a large complex cystic lesion with mass effect on the anterior thyroid gland, along with multiple neck and mediastinal necrotic lymph nodes, suspicion for metastasis. CT of the thorax showed lung nodules and a large left pleural effusion. Fluid was drained and sent for cytologic examination which revealed malignant cells predominantly in a micropapillary pattern with apically placed, bulged, "hobnail-like" appearance; intranuclear pseudo-inclusions or chromatin clearing was not seen. Based on cytomorphologic findings and immunohistochemical results (CK7 and PAX-8 positive; TTF-1, Napsin-A, and mesothelial markers negative), final diagnosis of HNPTC metastatic to pleural fluid was made. Fine-needle aspiration of neck mass showed similar cytomorphologic findings, confirming a thyroid origin. However, the patient experienced complications, rapid deterioration and died 6 months after diagnosis. The intersection of clinical-radiologic findings, cytology, and immunohistochemistry guided the identification of this rare variant of PTC as the origin of the malignant pleural effusion. We believe this case provides a valuable insight into the complexities involved in the diagnosis of thyroid carcinoma and emphasizes the significance of proper identification of rare variants., (© 2025 Wiley Periodicals LLC.)

The Sclerosing subtype of mucoepidermoid carcinoma is rare, with only 39 cases reported in literature. We present a new case of sclerosing mucoepidermoid carcinoma (SMEC) with MAML2 rearrangements. A 49-year-old woman with Sjögren's syndrome experienced recurrent submandibular sialadenitis and sialolithiasis, leading to the removal of her right gland. Postoperative imaging revealed a calcified mass in her left gland which was subsequently resected. The pathologic examination revealed a well-defined tumor with extensive fibrous stroma, predominantly epidermoid cells, and occasional mucinous components. There was a dense lymphocytic and plasma cell infiltrate at the tumor's periphery. Immunohistochemistry was positive for p40 and CK7, few IgG4+ plasma cells. No eosinophils were identified. Fluorescence in situ hybridization (FISH) revealed rearrangement of the MAML2 (11q21) region. Adjuvant radiation was not recommended because of the patient's history of autoimmune diseases and the fact that the tumor was small, localized, and had negative resection margins. The patient was advised to undergo a repeat CT scan of the neck, scheduled for 3 months later. This case highlights the importance of considering SMEC in the differential diagnosis of patients with sialolithiasis or Sjögren's syndrome., Competing Interests: Disclosure The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sarcomatoid carcinoma (SC) of the larynx is an uncommon subtype of squamous cell carcinoma which shows both squamous carcinoma and a sarcomatous component, including heterologous elements. The presence of rhabdomyosarcomatous elements in the larynx is extremely rare. Diagnosis of SC can be particularly challenging when the malignant epithelial component is not evident. We present a case of SC in a 72-year-old man with a superficial exophytic mass in the vocal cord initially misdiagnosed as rhabdomyosarcoma due to a predominant spindle cell component with rhabdomyoblastic features by morphology and immunohistochemistry. This case report aims to increase awareness that a rhabdomyoblastic heterologous component can be present in SC of the larynx and to consider this diagnosis in a mucosal exophytic malignant spindle cell neoplasm, even in the absence of epithelial differentiation., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Shine et al.)

Nephrogenic adenoma is a benign lesion of the urothelial tract characterized by tubules surrounded by thick, hyalinized basement membranes. There is a great variety of architectural patterns within nephrogenic adenomas, including patterns that mimic malignancy, such as focal clear or hobnail cells, areas of significant nuclear atypia, mitosis, and isolated cystic changes. This represents a diagnostic pitfall, where a malignant lesion can be mistaken for a nephrogenic adenoma, leading to a delay in diagnosis and treatment that adversely affects the outcome. In this case report, we describe a nephrogenic adenoma arising in a female urethral diverticulum and discuss the differential diagnosis, which includes clear cell carcinomas, microcystic variant urothelial carcinomas, and Skene's gland cysts., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Thanedar et al.)

Background: Tonsillar squamous cell carcinoma (TSCC) due to human papillomavirus (HPV) infection has seen a dramatic increase in recent years. Bilateral tonsillar squamous cell carcinoma (biTSCC) has a much lower incidence than unilateral TSCC and three main hypotheses of biTSCC pathogenesis prevail: field carcinogenesis, single-clone, and multiple HPV infections., Case: A 49-year-old Male with a remote history of chewing tobacco presented with symptoms of spitting up tissue and occasional hemoptysis. Physical exam showed a sole left tonsillar mass which was confirmed to be TSCC on biopsy. The patient's computed tomographic (CT) scan was consistent with this finding; however, positron emission tomography (PET) scan indicated a second tumor in the contralateral right tonsil. Surgical resection of both masses and selective neck dissection was performed, and the specimens were sent for further pathological analysis. No complications of surgery were noted and the final diagnosis of synchronous biTSCC was made. The tumors were a T2N0M0 left poorly differentiated TSCC (p16+, EGFR+, bcl2+) with basaloid features, and a T1N0M0 right well to moderately differentiated TSCC (p16+, EGFR+, bcl2-)., Conclusion: Our present case was notable for differing tumor pathology and karyotype analysis between the right and left masses, directly supporting the multiple HPV infections hypothesis of biTSCC pathogenesis. Further genetic characterization of tonsillar tumors is needed to better characterize TSCC and best guide medical/surgical therapy., (© 2022 The Authors. Cancer Reports published by Wiley Periodicals LLC.)

Pilomatricomas are benign skin tumors often encountered by otolaryngologists but frequently misdiagnosed. Although they can occur at any age, they commonly present in children as a discolored superficial lesion adhered to the overlying skin. Accurate preoperative diagnosis is crucial for appropriate management, which is surgical in most cases. Here, we present bilateral pilomatricomas mimicking features of several other diagnoses in a pediatric patient. The patient was successfully treated with surgical excision. This case presented a unique diagnostic challenge, as the lesions exhibited features of several common diagnoses. In general, surgical management of pilomatricoma is curative, and recurrence is rare.

Combined large cell neuroendocrine carcinoma (LCNEC) and squamous cell carcinoma (SCC) of the H&N are exceptionally rare. We present the case of combined p16 negative SCC and LCNEC of the oropharynx treated with combination chemotherapy. This is the third reported case of combined neuroendocrine carcinoma and SCC of the oropharynx., Competing Interests: The authors declare that there is no conflict of interest., (© 2022 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd.)

Background: Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is one of six diagnostic categories of The Bethesda System for Reporting Thyroid Cytopathology (BSRTC). The goal of our study is to assess the outcome of cases classified as AUS/FLUS at our institution., Methods: AUS/FLUS cases were identified by computer searching of the thyroid fine-needle aspiration (FNA) cases performed between 2010 and 2016. Outcomes were categorized as: follow-up surgery, repeat FNA or no follow-up available. Demographics, ultrasound findings and FNA diagnostic criteria were reviewed for AUS/FLUS cases with follow-up surgical pathology diagnosis., Results: Our AUS/FLUS thyroid FNA rate was 6% (117 out of 1984 FNAs). Only 15% of the AUS/FLUS cases had repeat FNA, while 41% underwent surgery. The risk of malignancy (ROM) for cases with follow-up surgery was 17%. When considering all AUS/FLUS cases, the ROM was 7%. Statistically, benign neoplasms were more likely to be single lesions on ultrasound comparing to malignant neoplasms, and to exhibit architectural atypia as opposed to non-neoplastic lesions on FNA. The malignancy rates among patients that directly went to surgical resection (17%) and patients having repeat FNA after the first AUS/FLUS diagnosis followed by surgery (29%) was not significantly different. However, repeat FNA was able to reclassify the majority of cases into more definitive categories., Conclusion: The outcome of the thyroid FNAs diagnosed as AUS/FLUS in our institution meets the benchmark statistics for AUS/FLUS rate and ROM. This study constitutes a valuable quality assurance measure and serves as a baseline for subsequent quality improvement., (© 2021 Wiley Periodicals LLC.)

Background: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is based on risk stratification. We presented our experience with fine-needle aspiration cytology (FNAC) for the diagnosis of salivary glands lesions by applying the MSRSGC categorization to the cytological diagnoses, and determined risk of malignancy (ROM) for each category., Methods: Fine-needle aspiration cytology of salivary gland lesions performed over a 6-year period was retrieved. FNAC results were retrospectively categorized according to the MSRSGC criteria, and correlated with corresponding histologic follow-up. ROM for each diagnostic category was calculated., Results: A total of 208 FNAC of salivary gland lesions were reviewed and retrospectively categorized as: non-diagnostic (ND) 23 (11%), non-neoplastic (NN) 54 (26%), atypia of undetermined significance (AUS) 10 (4.8%), benign neoplasms (BN) 77 (37%), salivary gland of uncertain malignant potential (SUMP) 13 (6.3%), suspicious for malignancy (SM) 7 (3.4%), and malignant (M) 24 (11.5%). Histopathological follow-up was available for 84 of 208 cases (40.4%). Overall concordance rate between FNAC and histology was 78.8%. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated as 93.3%, 94.6%, 82.4%, and 98.2%, respectively. Diagnostic accuracy to distinguish benign from malignant disease was 94.4%. ROM for each category was ND 0%, NN 0%, AUS 75%, BN 2.2%, SUMP 28.6%, SM 50%, and M 100%., Conclusion: Fine-needle aspiration cytology continues to be an accurate diagnostic tool for most salivary gland neoplasms showing classical morphologic features. However, difficult cases with unusual or overlapping features will occur. In these situations, the use of MSRSGC risk-stratification could be helpful to define appropriate management., (© 2020 Wiley Periodicals LLC.)

Background: Fine-needle aspiration (FNA) is an important tool for the diagnosis of infectious diseases. In this study, we assessed the efficacy of FNA cytology in early diagnosis of fungal infections., Methods: This was a retrospective study from January 2016 to August 2018. Electronic archives were searched for FNAs from superficial and deep lesions obtained from various sites with the diagnosis of fungal infection. Each case was evaluated for underlying predisposing conditions, FNA source, radiologic findings, culture, and serology results., Results: A total of 15 cases were identified from the following sites: lung (eight), cervical lymph nodes (four), soft tissue (two), and retroperitoneal lymph node (one). Predisposing conditions were found in 11 patients: HIV (five), malignancy (three), and post-transplant (three). Imaging impression was mostly malignancy vs infection. In all 15 cases, the diagnosis of fungal infection was done by FNA cytology. The presumptive genus specific diagnoses based on yeast morphology was given in 12 cases (five Histoplasma, four Cryptococcus, and three Coccidioides). The diagnosis of fungal infection was provided within 24 h in nine cases, four during onsite evaluation. Microbial cultures were confirmatory in seven cases, and five cases exhibited negative cultures with positive serology. Out of the 15 patients, 14 were discharged in fair condition, and one died with complications of heart graft failure., Conclusion: FNA is a rapid and reliable method for early diagnosis of fungal infections, allowing a prompt and appropriate management, especially in immunocompromised patients. When onsite evaluation indicates infectious process, cultures can be timely done., (© 2020 Wiley Periodicals, Inc.)

Desmoplasia, a hallmark of a head and neck cancer, has both biologic and physiologic effects on cancer progression and chemotherapeutic response. Mesenchymal stem/stromal cells (MSCs), also known as mesenchymal stromal progenitor cells, have been shown to play a role in cancer progression, alter apoptotic responses, and confer resistance to chemotherapy in various carcinomas. The pathophysiology of MSCs with respect to tumorigenesis is widely reported in other cancers and is sparsely reported in oral squamous cell carcinomas (OSCCs). We previously reported paracrine mediated PDGF-AA/PDGFR-α signaling to underlie MSCs chemotaxis in OSCC. Given the poor clinical response to primary chemotherapy, we hypothesized that MSCs may alter cancer cell sensitivity to cisplatin through activation of PDGFR-α mediated signaling pathways. Co-culture of MSCs with human derived OSCC cell lines, JHU-012 and -019, resulted in a significant increase in the production of PDGF-AA and MCP-1 compared to cancer cells grown alone ( p < 0.005) and was accompanied by an increase in the phosphorylation state of PDGFR-α ( p < 0.02) and downstream target AKT at S473 ( p < 0.025) and T308 ( p < 0.02). JHU-012 and -019 cancer cells grown in co-culture were significantly less apoptotic ( p < 0.001), expressed significantly higher levels of Bcl-2 ( p < 0.04) with a concomitant significant decrease in bid expression ( p < 0.001) compared to cancer cells grown alone. There was a significant increase in the cisplatin dose response curve in cancer cell clones derived from JHU-012 and 019 cancer cells grown in co-culture with MSCs compared to clones derived from cancer cells grown alone ( p < 0.001). Moreover clones derived from JHU-012 cells grown in co-culture with MSCs were significantly more susceptible to cisplatin following pretreatment with, crenolanib, a PDGFR inhibitor, compared to cancer cells grown alone or in co-culture with MSCs ( p < 0.0001). These findings suggest that crosstalk between cancer cells and MSCs is mediated, at least in part, by activation of autocrine PDGF-AA/PDGFR-α loop driving AKT-mediated signaling pathways, resulting in reduced cancer cell sensitivity to cisplatin through alterations in apoptosis., (Copyright © 2020 Wang, Cui, Clement, Nawgiri, Powell, Pinchuk and Watts.)

Introduction: Plexiform schwannoma is a rare variant of schwannoma that accounts for only 5% of all schwannomas. Herein, we present a rare case of plexiform schwannoma of the tongue in a pediatric patient with neurofibromatosis type 2 (NF2)., Case Presentation: A 13-year-old female presented with a growing left-sided tongue mass. The patient has a past medical history of NF2. The tongue mass was excised and histopathological examination revealed a spindle cell tumor with multinodular growth pattern, with Verocay bodies' formation. Tumor cells were strongly positive for S-100 protein and negative for smooth muscle actin (SMA), and EMA highlighted perineural fibroblasts surrounding tumor nodules. These findings were diagnostic of plexiform schwannoma., Conclusion: Plexiform schwannoma of the tongue is an extremely rare tumor seen in patients with NF2. Clinical examination and histopathological evaluation are important for diagnosis of plexiform schwannoma.

Background: Fine-needle aspiration (FNA) is an important tool for the diagnosis of infectious disease. FNA material should be appropriately submitted for cultures when indicated by preliminary findings. Correlation of cytologic diagnoses with culture results are important quality assurance tools. The current study reviewed 14 years of FNA-culture correlation., Methods: FNA cytology-culture correlation records from the years 1996 through 2007 and 2010 through 2011 were retrieved from electronic databases compiled for histology and culture correlation. Correlation was limited to those cases for which material was submitted for culture from the FNA sample. Culture results were retrieved from the laboratory or hospital information system., Results: Correlative data included 770 cases. Cytology, culture, or both were positive for microbes in 416 of 770 samples (54%), excluding cultured bacterial skin contaminants. Among the 204 bacteria cases, 93 (46%) were identified by cytology and culture, 92 (45%) were identified by culture only, and 19 (9%) were identified by cytology only. Among the 16 cases of Actinomycetales, 8 (50%) were identified by cytology and culture, 5 (31%) were identified by culture only, and 3 (19%) were identified by cytology only. Of the 129 cases of mycobacteria, 63 (49%) were identified by cytology and culture, 44 (34%) were identified by culture only, and 22 (17%) were identified by cytology only. Among the 67 cases of fungi, 34 (51%) were identified by cytology only, with 15 of these 34 cases being fungal hyphae; 25 cases (37%) were identified by cytology and culture, with a 100% concordance between the cytology diagnosis and culture result; and 8 cases (12%) were identified by culture only., Conclusions: FNA cytology-culture correlation is a valuable tool with which to assess the efficacy and limitations of the direct diagnosis of infectious agents, and to identify types of infections that may be negative on culture but positive on cytology diagnosis., (© 2015 American Cancer Society.)

Congo red stain apple-green birefringence under polarized light is the most popular method for detecting amyloid; however, it has limitations. The goal of this study was to evaluate if examination of Congo red stain by fluorescent microscopy (FM) significantly enhances the diagnostic yield. Congo red-stained tissue sections were retrospectively and prospectively examined by light microscopy (LM) with and without polarizer and by FM using the Texas red filter and results by each method compared. Congo red-stained amyloid recognized by LM was unequivocally and easily identified by FM in each of 48 cases. In 22 of them, FM either confirmed the presence of a small amount of amyloid or lead to a definitive diagnosis, which was otherwise missed. Eight cases with Congo red-negative by LM were also negative by FM. In 8 cases with a false-positive Congo red stain, FM still detected the signal in 5, but it was absent in 3 cases. In conclusion, Congo red fluorescence improves the diagnostic yield of LM for both positive and negative cases., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Procalcitonin (PCT) is expressed in nonthryoidal tissues of humans during severe infections. Serum PCT levels are measured to diagnose and guide therapy, and there is some evidence that PCT may also contribute to the pathogenesis of sepsis. We tested whether disruption of the gene encoding PCT in mice affected the course of sepsis. Mice with exons 2-5 of the gene encoding calcitonin/calcitonin gene-related polypeptide α (Calca) knocked out and congenic C57BL/6J control mice were challenged with aerosolized Streptococcus pneumoniae or Pseudomonas aeruginosa, or injected intraperitoneally with S. pneumoniae. There were no significant differences in the survival of knockout and control mice in the two pneumonia models, and no significant differences in weight loss, splenic bacterial counts, or blood leukocyte levels in the peritoneal sepsis model. To verify disruption of the Calca gene in knockout mice, the absence of calcitonin in the serum of knockout mice and its presence and inducibility in control mice were confirmed. To evaluate PCT expression in nonthyroidal tissues of control mice, transcripts were measured in multiple organs. PCT transcripts were not significantly expressed in liver or spleen of control mice challenged with aerosolized P. aeruginosa or intraperitoneal endotoxin, and were expressed in lung only at low levels, even though serum IL-6 rose 3,548-fold. We conclude that mice are not an ideal loss-of-function model to test the role of PCT in the pathogenesis of sepsis because of low nonendocrine PCT expression during infection and inflammation. Nonetheless, our studies demonstrate that nonendocrine PCT expression is not necessary for adverse outcomes from sepsis.

We report the case of a 22-year-old man who presented with a Mycobacterium haemophilum and Histoplasma capsulatum coinfection occurring 21 years after a living-donor-related renal transplant.

Lymphoma is the most frequent malignant tumor of the ocular adnexa with the most common histologic type being extranodal marginal zone B-cell lymphoma (EMZL) of mucosa-associated lymphoid tissue (MALT lymphoma). Here we report a case of a 28 year-old male who presented with a left conjunctival mass of one year duration. A diagnosis of primary MALT lymphoma of the conjunctiva was made based on morphologic and immunopheno-typic studies. Chromosome analysis revealed a male karyotype with a translocation t (5;11) (q33;p11.2) as the primary chromosomal abnormality, which, to the best of our knowledge, is the first reported translocation in MALT lym-phomas and ocular MALT lymphomas as well.

Sarcomas are a rare occurrence accounting for roughly 1% of all cancer cases reported. Of these, 9-18% will be identified as liposarcoma. Overall, only 4-9% of all liposarcomas occur in the head and neck region. As such, it is a rare event to see a primary liposarcoma of the aerodigestive tract. These tumors are typically misdiagnosed secondary to their indolent, asymptomatic course and similarities in appearance to other benign lesions. An understanding of these lesions will help clinicians appropriately manage their patients. We present a case of a 60-year male with a primary supraglottic myxoid liposarcoma, and provide relevant information about liposarcomas.

Pneumonia is a serious problem worldwide. We recently demonstrated that innate defense mechanisms of the lung are highly inducible against pneumococcal pneumonia. To determine the breadth of protection conferred by stimulation of lung mucosal innate immunity, and to identify cells and signaling pathways activated by this treatment, mice were treated with an aerosolized bacterial lysate, then challenged with lethal doses of bacterial and fungal pathogens. Mice were highly protected against a broad array of Gram-positive, Gram-negative, and class A bioterror bacterial pathogens, and the fungal pathogen, Aspergillus fumigatus. Protection was associated with rapid pathogen killing within the lungs, and this effect was recapitulated in vitro using a respiratory epithelial cell line. Gene expression analysis of lung tissue showed marked activation of NF-kappaB, type I and II IFN, and antifungal Card9-Bcl10-Malt1 pathways. Cytokines were the most strongly induced genes, but the inflammatory cytokines TNF and IL-6 were not required for protection. Lung-expressed antimicrobial peptides were also highly up-regulated. Taken together, stimulated innate resistance appears to occur through the activation of multiple host defense signaling pathways in lung epithelial cells, inducing rapid pathogen killing, and conferring broad protection against virulent bacterial and fungal pathogens. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value for protection of patients with neutropenia or impaired adaptive immunity against opportunistic pneumonia, and for defense of immunocompetent subjects against a bioterror threat or epidemic respiratory infection.

Background: Protective host responses to respiratory pathogens are typically characterized by inflammation. However, lung inflammation is not always protective and it may even become deleterious to the host. We have recently reported substantial protection against Streptococcus pneumoniae (pneumococcal) pneumonia by induction of a robust inflammatory innate immune response to an inhaled bacterial lysate. Conversely, the allergic inflammation associated with asthma has been proposed to promote susceptibility to pneumococcal disease. This study sought to determine whether preexisting allergic lung inflammation influences the progression of pneumococcal pneumonia or reduces the inducibilty of protective innate immunity against bacteria., Methods: To compare the effect of different inflammatory and secretory stimuli on defense against pneumonia, intraperitoneally ovalbumin-sensitized mice were challenged with inhaled pneumococci following exposure to various inhaled combinations of ovalbumin, ATP, and/or a bacterial lysate. Thus, allergic inflammation, mucin degranulation and/or stimulated innate resistance were induced prior to the infectious challenge. Pathogen killing was evaluated by assessing bacterial CFUs of lung homogenates immediately after infection, the inflammatory response to the different conditions was evaluated by measurement of cell counts of bronchoalveolar lavage fluid 18 hours after challenge, and mouse survival was assessed after seven days., Results: We found no differences in survival of mice with and without allergic inflammation, nor did the induction of mucin degranulation alter survival. As we have found previously, mice treated with the bacterial lysate demonstrated substantially increased survival at seven days, and this was not altered by the presence of allergic inflammation or mucin degranulation. Allergic inflammation was associated with predominantly eosinophilic infiltration, whereas the lysate-induced response was primarily neutrophilic. The presence of allergic inflammation did not significantly alter the neutrophilic response to the lysate, and did not affect the induced bacterial killing within the lungs., Conclusion: These results suggest that allergic airway inflammation neither promotes nor inhibits progression of pneumococcal lung infection in mice, nor does it influence the successful induction of stimulated innate resistance to bacteria.

Background: Influenza pneumonia causes high mortality every year, and pandemic episodes kill millions of people. Influenza-related mortality has been variously ascribed to an ineffective host response that fails to limit viral replication, an excessive host inflammatory response that results in lung injury and impairment of gas exchange, or to bacterial superinfection. We sought to determine whether lung inflammation promoted or impaired host survival in influenza pneumonia., Methods and Findings: To distinguish among these possible causes of influenza-related death, we induced robust lung inflammation by exposing mice to an aerosolized bacterial lysate prior to challenge with live virus. The treatment induced expression of the inflammatory cytokines IL-6 and TNF in bronchoalveolar lavage fluid 8- and 40-fold greater, respectively, than that caused by lethal influenza infection. Yet, this augmented inflammation was associated with striking resistance to host mortality (0% vs 90% survival, p = 0.0001) and reduced viral titers (p = 0.004). Bacterial superinfection of virus infected lungs was not observed. When mice were repeatedly exposed to the bacterial lysate, as would be clinically desirable during an influenza epidemic, there was no tachyphylaxis of the induced viral resistance. When the bacterial lysate was administered after the viral challenge, there was still some mortality benefit, and when ribavirin was added to the aerosolized bacterial lysate, host survival was synergistically improved (0% vs 93.3% survival, p<0.0001)., Conclusions: Together, these data indicate that innate immune resistance to influenza can be effectively stimulated, and suggest that ineffective rather than excessive inflammation is the major cause of mortality in influenza pneumonia.

Nontypeable Haemophilus influenzae (NTHi) commonly colonizes the lower airways of patients with chronic obstructive pulmonary disease (COPD). Whether it contributes to COPD progression is unknown. Here, we determined which aspects of the COPD phenotype can be induced by repetitive exposure to NTHi products. Mice were exposed weekly to an aerosolized NTHi lysate, and inflammation was evaluated by measurement of cells and cytokines in bronchoalveolar lavage fluid (BALF) and immunohistochemical staining; structural changes were evaluated histochemically by periodic acid fluorescent Schiff's reagent, Masson's trichrome, and Picrosirius red staining; mucin gene expression was measured by quantitative RT-PCR; and the role of TNF-alpha was examined by transgenic airway overexpression and use of an inhibitory antibody. NTHi lysate induced rapid activation of NF-kappaB in airway cells and increases of inflammatory cytokines and neutrophils in BALF. Repetitive exposure induced infiltration of macrophages, CD8+ T cells, and B cells around airways and blood vessels, and collagen deposition in airway and alveolar walls, but airway mucin staining and gel-forming mucin transcripts were not increased. Transgenic overexpression of TNF-alpha caused BALF neutrophilia and inflammatory cell infiltration around airways, but not fibrosis, and TNF-alpha neutralization did not reduce BALF neutrophilia in response to NTHi lysate. In conclusion, NTHi products elicit airway inflammation in mice with a cellular and cytokine profile similar to that in COPD, and cause airway wall fibrosis but not mucous metaplasia. TNF-alpha is neither required for inflammatory cell recruitment nor sufficient for airway fibrosis. Colonization by NTHi may contribute to the pathogenesis of small airways disease in patients with COPD.