Interferon-independent processes constrain measles virus cell-to-cell spread in primary human airway epithelial cells

Amplification of measles virus (MeV) in human airway epithelia may contribute to its extremely high contagious nature. We use well-differentiated primary cultures of human airway epithelial cells (HAE) to model ex vivo how MeV spreads in human airways. In HAE, MeV spreads cell-to-cell for 3-5 days, but then, infectious center growth is arrested. What stops MeV spread in HAE is not understood, but interferon (IFN) is known to slow MeV spread in other in vitro and in vivo models. Here, we assessed the role of type I and type III IFN in arresting MeV spread in HAE. The addition of IFN-β or IFN-λ1 to the medium of infected HAE slowed MeV infectious center growth, but when IFN receptor signaling was blocked, infectious center size was not affected. In contrast, blocking type-I IFN receptor signaling enhanced respiratory syncytial virus spread. HAE were also infected with MeV mutants defective for the V protein. The V protein has been demonstrated to interact with both MDA5 and STAT2 to inhibit activation of innate immunity; however, innate immune reactions were unexpectedly muted against the V-defective MeV in HAE. Minimal innate immunity activation was confirmed by deep sequencing, quantitative RT-PCR, and single-cell RNA-seq analyses of the transcription of IFN and IFN-stimulated genes. We conclude that in HAE, IFN-signaling can contribute to slowing infectious center growth; however, IFN-independent processes are most important for limiting cell-to-cell spread. IMPORTANCE Fundamental biological questions remain about the highly contagious measles virus (MeV). MeV amplifies within airway epithelial cells before spreading to the next host. This final step likely contributes to the ability of MeV to spread host-to-host. Over the course of 3-5 days post-infection of airway epithelial cells, MeV spreads directly cell-to-cell and forms infectious centers. Infectious center formation is unique to MeV. In this study, we show that interferon (IFN) signaling does not explain why MeV cell-to-cell spread is ultimately impeded within the cell layer. The ability of MeV to spread cell-to-cell in airway cells without appreciable IFN induction may contribute to its highly contagious nature. This study contributes to the understanding of a significant global health concern by demonstrating that infectious center formation occurs independent of the simplest explanation for limiting viral transmission within a host.

IL-13 induced inflammation increases DPP4 abundance but does not enhance MERS-CoV replication in airway epithelia

BACKGROUND

Chronic pulmonary conditions such as asthma and COPD increase the risk of morbidity and mortality during infection with the Middle East respiratory syndrome coronavirus (MERS-CoV). We hypothesized that individuals with such comorbidities are more susceptible to MERS-CoV infection due to increased expression of its receptor, dipeptidyl peptidase 4 (DPP4).

METHODS

We modeled chronic airway disease by treating primary human airway epithelia with the Th2 cytokine IL-13, examining how this impacted DPP4 protein levels along with MERS-CoV entry and replication.

RESULTS

IL-13 exposure for 3 days led to increased DPP4 protein abundance, while a 21-day treatment increased DPP4 levels and caused goblet cell metaplasia. Surprisingly, despite this increase in receptor availability, MERS-CoV entry and replication were not significantly impacted by IL-13 treatment.

CONCLUSIONS

Our results suggest that increased DPP4 abundance is likely not the primary mechanism leading to increased MERS severity in the setting of Th2 inflammation. Transcriptional profiling analysis highlighted the complexity of IL-13 induced changes in airway epithelia, including altered expression of genes involved in innate immunity, antiviral responses, and maintenance of the extracellular mucus barrier. These data suggest that additional factors likely interact with DPP4 abundance to determine MERS-CoV infection outcomes.

Inter-individual Variation in Receptor Expression Influences MERS-CoV Infection and Immune Responses in Airway Epithelia

Middle East respiratory syndrome coronavirus (MERS-CoV) causes respiratory infection in humans, with symptom severity that ranges from asymptomatic to severe pneumonia. Known risk factors for severe MERS include male sex, older age, and the presence of various comorbidities. MERS-CoV gains entry into cells by binding its receptor, dipeptidyl peptidase 4 (DPP4), on the surface of airway epithelia. We hypothesized that expression of this receptor might be an additional determinant of outcomes in different individuals during MERS-CoV infection. To learn more about the role of DPP4 in facilitating MERS-CoV infection and spread, we used ELISA and immunofluorescent staining to characterize DPP4 expression in well-differentiated primary human airway epithelia (HAE). We noted wide inter-individual variation in DPP4 abundance, varying by as much as 1000-fold between HAE donors. This variability appears to influence multiple aspects of MERS-CoV infection and pathogenesis, with greater DPP4 abundance correlating with early, robust virus replication and increased cell sloughing. We also observed increased induction of interferon and some interferon-stimulated genes in response to MERS-CoV infection in epithelia with the greatest DPP4 abundance. Overall, our results indicate that inter-individual differences in DPP4 abundance are one host factor contributing to MERS-CoV replication and host defense responses, and highlight how HAE may serve as a useful model for identifying risk factors associated with heightened susceptibility to serious respiratory pathogens.

Intersubject Variation in ACE2 Protein Expression in Human Airway Epithelia and Its Relationship to Severe Acute Respiratory Syndrome Coronavirus 2

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 ) initiates entry into airway epithelia by binding its receptor, angiotensin-converting enzyme 2 (ACE2).

METHODS

To explore whether interindividual variation in ACE2 abundance contributes to variability in coronavirus disease 2019 (COVID-19) outcomes, we measured ACE2 protein abundance in primary airway epithelial cultures derived from 58 human donor lungs.

RESULTS

We found no evidence for sex- or age-dependent differences in ACE2 protein expression. Furthermore, we found that variations in ACE2 abundance had minimal effects on viral replication and induction of the interferon response in airway epithelia infected with SARS-CoV-2.

CONCLUSIONS

Our results highlight the relative importance of additional host factors, beyond viral receptor expression, in determining COVID-19 lung disease outcomes.

Airway Surface Liquid Has Innate Antiviral Activity That Is Reduced in Cystic Fibrosis

Although chronic bacterial infections and inflammation are associated with progressive lung disease in patients with cystic fibrosis (CF), much less is known regarding the contributions of respiratory viral infections to this process. Clinical studies suggest that antiviral host defenses may be compromised in individuals with CF, and CF airway epithelia exhibit impaired antiviral responses in vitro. Here, we used the CF pig model to test the hypothesis that the antiviral activity of respiratory secretions is reduced in CF. We developed an in vitro assay to measure the innate antiviral activity present in airway surface liquid (ASL) from CF and non-CF pigs. We found that tracheal and nasal ASL from newborn non-CF pigs exhibited dose-dependent inhibitory activity against several enveloped and encapsidated viruses, including Sendai virus, respiratory syncytial virus, influenza A, and adenovirus. Importantly, we found that the anti-Sendai virus activity of nasal ASL from newborn CF pigs was significantly diminished relative to non-CF littermate controls. This diminution of extracellular antiviral defenses appears to be driven, at least in part, by the differences in pH between CF and non-CF ASL. These data highlight the novel antiviral properties of native airway secretions and suggest the possibility that defects in extracellular antiviral defenses contribute to CF pathogenesis.

Book Review: Sustainable Thinking: Ensuring Your Library’s Future in an Uncertain World

Although the concept of “sustainability” has many possible meanings, its connection to environmental issues is perhaps the most familiar. Thus, a reader coming across Rebekkah Smith Aldrich’s new book might assume that it is primarily about how libraries can best demonstrate stewardship of environmental resources. While this is certainly one important piece of the discussion, Sustainable Thinking has a much larger goal: advocating the capacity of libraries to build communities, whether it be through environmental, financial, leadership, political, or other initiatives.

Newborn Cystic Fibrosis Pigs Have a Blunted Early Response to an Inflammatory Stimulus

RATIONALE

Studies suggest that inappropriate responses to proinflammatory stimuli might contribute to inflammation in cystic fibrosis (CF) lungs. However, technical challenges have made it difficult to distinguish whether altered responses in CF airways are an intrinsic defect or a secondary effect of chronic disease in their tissue of origin. The CF pig model provides an opportunity to study the inflammatory responses of CF airways at birth, before the onset of infection and inflammation.

OBJECTIVES

To test the hypothesis that acute inflammatory responses are perturbed in porcine CF airways.

METHODS

We investigated the inflammatory responses of newborn CF and non-CF pig airways following a 4-hour exposure to heat-killed Staphylococcus aureus, in vivo and in vitro.

MEASUREMENTS AND MAIN RESULTS

Following an in vivo S. aureus challenge, markers of inflammation were similar between CF and littermate control animals through evaluation of bronchoalveolar lavage and tissues. However, transcriptome analysis revealed genotype-dependent differences as CF pigs showed a diminished host defense response compared with their non-CF counterparts. Furthermore, CF pig airways exhibited an increase in apoptotic pathways and a suppression of ciliary and flagellar biosynthetic pathways. Similar differences were observed in cultured airway epithelia from CF and non-CF pigs exposed to the stimulus.

CONCLUSIONS

Transcriptome profiling suggests that acute inflammatory responses are dysregulated in the airways of newborn CF pigs.

Book Review: International Librarianship at Home and Abroad

What is meant by “international librarianship”? The term can be difficult to define, potentially encompassing a vast array of library activities, including collecting materials published abroad, participating in librarian exchanges, and attending international library conferences.

Book Review: Students Lead the Library: The Importance of Student Contributions to the Academic Library

Academic libraries, often said to be the “heart of the university,” owe their existence and importance to the students they serve. Students are at the core of the library mission, driving decisions in collections, services, innovation, outreach, and research support. However, their direct role in institutional planning is minimal, and their primary role is most often that of library user. Given their importance to libraries, how can students actively participate in library success? Students Lead the Library offers several examples of student involvement in action, or, as editors Sara Arnold-Garza and Carissa Tomlinson state, “this book seeks to elevate the act of asking students what they need and want by not simply involving students, but instead putting them into a leadership role, where they will determine what gets improved and how” (vii).

Book Review: Talking Conflict: The Loaded Language of Genocide, Political Violence, Terrorism, and Warfare

The language used to describe conflict situations, whether military, political, or personal, has the potential to help resolve or escalate. Terms such as “collateral damage,” “ethnic cleansing,” and “final solution” often refer to historical events, but can also be used to condemn or endorse particular points of view in political speeches, the media, and local debate. Euphemisms, oxymorons, propaganda, jargon: all come into play. The nuanced and powerful rhetoric of conflict is the topic of Talking Conflict, an interesting and wide-ranging encyclopedia discussing the impact of linguistics, political science, journalism, and other fields on the language of conflict.

Book Review: American Myths, Legends, and Tall Tales: An Encyclopedia of American Folklore

Compilations of American folklore are constantly being rewritten to reflect the increasing diversity and variety of American culture. Many readers grew up with Benjamin Botkin’s classic collection A Treasury of American Folklore (Crown 1944), which featured a foreword written by Carl Sandburg and stories about Pecos Bill, Johnny Appleseed, Brer Rabbit and other popular myths, legends, and tall tales. Today, new legends are entering the folklore lexicon to reflect the influence of urban myths, historical events, science fiction, conspiracy theories, and mass media. This three-volume set offers a fascinating look at both traditional and newer folklore, including “Internet Hoaxes,” the “John Lennon shooting,” “Roswell,” and “Slender Man.”

Book Review: Adding Value to Libraries, Archives, and Museums: Harnessing the Force That Drives Your Organization’s Future

Value in libraries, archives, museums, and other cultural organizations has traditionally been centered on collections and services. Today’s libraries are looking at new ways to make their operations valuable to their patrons. Adding Value is geared toward library managers and administrators focusing on understanding, identifying, planning, and implementing services with an eye toward new definitions of value.

Book Review: The Gilded Age and Progressive Era: A Historical Exploration of Literature

One of the latest volumes in ABC-CLIO/Greenwood’s “Historical Explorations of Literature” series, The Gilded Age and Progressive Era is a useful and interesting introduction to framing key literary works of this time period in their historical context. Each volume in the series presents a discussion of four or five representative works of a historical era, such as the Harlem Renaissance, the Chicano Movement, the Jazz Age, and the Civil War Era.

Book Review: Encyclopedia of Education Economics & Finance

Comprehensive studies of educational systems in an economic and social sciences context are relatively recent. The 1966 Equality of Educational Opportunity report (also known as the Coleman Report) addressed the availability of equal educational opportunities to children of different races, religions, and national origins in response to the Civil Rights Act of 1964. This was an early example of social science research being used to influence national policy. Since then, educational finance research has blossomed into an area of study that influences decision makers at the national, state and local levels in resource allocation, assessment, and school organizational and restructuring policies.

Increased susceptibility to otitis media in a Splunc1-deficient mouse model

Otitis media (inflammation of the middle ear) is one of the most common diseases of early childhood. Susceptibility to otitis is influenced by a number of factors, including the actions of innate immune molecules secreted by the epithelia lining the nasopharynx, middle ear and Eustachian tube. The SPLUNC1 (short palate, lung, nasal epithelial clone 1) protein is a highly abundant secretory product of the mammalian nasal, oral and respiratory mucosa that is thought to play a multifunctional role in host defense. In this study we investigated Splunc1 expression in the ear of the mouse, and examined whether this protein contributes to overall host defense in the middle ear and/or Eustachian tube. We found that Splunc1 is highly expressed in both the surface epithelium and in submucosal glands in these regions in wild-type mice. In mice lacking Splunc1, we noted histologically an increased frequency of otitis media, characterized by the accumulation of leukocytes (neutrophils with scattered macrophages), proteinaceous fluid and mucus in the middle ear lumens. Furthermore, many of these mice had extensive remodeling of the middle ear wall, suggesting a chronic course of disease. From these observations, we conclude that loss of Splunc1 predisposes mice to the development of otitis media. The Splunc1^−/− mouse model should help investigators to better understand both the biological role of Splunc1 as well as host defense mechanisms in the middle ear.

Summary: We document expression of the innate immune factor Splunc1 in the murine middle ear and Eustachian tube, and describe spontaneous development of otitis media in mice lacking functional Splunc1.

miR-31 dysregulation in cystic fibrosis airways contributes to increased pulmonary cathepsin S production

RATIONALE

Cathepsin S (CTSS) activity is increased in bronchoalveolar lavage (BAL) fluid from patients with cystic fibrosis (CF). This activity contributes to lung inflammation via degradation of antimicrobial proteins, such as lactoferrin and members of the β-defensin family.

OBJECTIVES

In this study, we investigated the hypothesis that airway epithelial cells are a source of CTSS, and mechanisms underlying CTSS expression in the CF lung.

METHODS

Protease activity was determined using fluorogenic activity assays. Protein and mRNA expression were analyzed by ELISA, Western blotting, and reverse-transcriptase polymerase chain reaction.

MEASUREMENTS AND MAIN RESULTS

In contrast to neutrophil elastase, CTSS activity was detectable in 100% of CF BAL fluid samples from patients without Pseudomonas aeruginosa infection. In this study, we identified epithelial cells as a source of pulmonary CTSS activity with the demonstration that CF airway epithelial cells express and secrete significantly more CTSS than non-CF control cells in the absence of proinflammatory stimulation. Furthermore, levels of the transcription factor IRF-1 correlated with increased levels of its target gene CTSS. We discovered that miR-31, which is decreased in the CF airways, regulates IRF-1 in CF epithelial cells. Treating CF bronchial epithelial cells with a miR-31 mimic decreased IRF-1 protein levels with concomitant knockdown of CTSS expression and secretion.

CONCLUSIONS

The miR-31/IRF-1/CTSS pathway may play a functional role in the pathogenesis of CF lung disease and may open up new avenues for exploration in the search for an effective therapeutic target.

Where Do We Go from Here? Informing Academic Library Staffing through Reference Transaction Analysis

This study conducted a systematic sample of every 70th reference transaction from over a three-year period and analyzed 1,852 reference transactions asked at an academic library system’s fifteen face-to-face (f2f) service points as well as via telephone, e-mail, and chat. Findings indicate two-thirds of the total questions asked were location-based questions about the library. Also, 80.2 percent of location-based questions and 77.2 percent of subject-based questions were asked f2f. Analysis of location-based reference questions informs effective deployment of librarians and staff at library service points as well as the development of mobile library apps.

Chest radiography for predicting the cause of febrile illness among inpatients in Moshi, Tanzania

AIM

To describe chest radiographic abnormalities and assess their usefulness for predicting causes of fever in a resource-limited setting.

MATERIALS AND METHODS

Febrile patients were enrolled in Moshi, Tanzania, and chest radiographs were evaluated by radiologists in Tanzania and the United States. Radiologists were blinded to the results of extensive laboratory evaluations to determine the cause of fever.

RESULTS

Of 870 febrile patients, 515 (59.2%) had a chest radiograph available; including 268 (66.5%) of the adolescents and adults, the remainder were infants and children. One hundred and nineteen (44.4%) adults and 51 (20.6%) children were human immunodeficiency virus (HIV)-infected. Among adults, radiographic abnormalities were present in 139 (51.9%), including 77 (28.7%) with homogeneous and heterogeneous lung opacities, 26 (9.7%) with lung nodules, 25 (9.3%) with pleural effusion, 23 (8.6%) with cardiomegaly, and 13 (4.9%) with lymphadenopathy. Among children, radiographic abnormalities were present in 87 (35.2%), including 76 (30.8%) with homogeneous and heterogeneous lung opacities and six (2.4%) with lymphadenopathy. Among adolescents and adults, the presence of opacities was predictive of Streptococcus pneumoniae and Coxiella burnetii, whereas the presence of pulmonary nodules was predictive of Histoplasma capsulatum and Cryptococcus neoformans.

CONCLUSIONS

Chest radiograph abnormalities among febrile inpatients are common in northern Tanzania. Chest radiography is a useful adjunct for establishing an aetiologic diagnosis of febrile illness and may provide useful information for patient management, in particular for pneumococcal disease, Q fever, and fungal infections.

PEG1/MEST and IGF2 DNA methylation in CIN and in cervical cancer

INTRODUCTION

Although most invasive cervical cancer (ICC) harbor <20 human papillomavirus (HPV) genotypes, use of HPV screening to predict ICC from HPV has low specificity, resulting in multiple and costly follow-up visits and overtreatment. We examined DNA methylation at regulatory regions of imprinted genes in relation to ICC and its precursor lesions to determine if methylation profiles are associated with progression of HPV-positive lesions to ICC.

MATERIALS AND METHODS

We enrolled 148 controls, 38 CIN and 48 ICC cases at Kilimanjaro Christian Medical Centre from 2008 to 2009. HPV was genotyped by linear array and HIV-1 serostatus was tested by two rapid HIV tests. DNA methylation was measured by bisulfite pyrosequencing at regions regulating eight imprinted domains. Logistic regression models were used to estimate odd ratios.

RESULTS

After adjusting for age, HPV infection, parity, hormonal contraceptive use, and HIV-1 serostatus, a 10 % decrease in methylation levels at an intragenic region of IGF2 was associated with higher risk of ICC (OR 2.00, 95 % CI 1.14-3.44) and cervical intraepithelial neoplasia (CIN) (OR 1.51, 95 % CI 1.00-2.50). Methylation levels at the H19 DMR and PEG1/MEST were also associated with ICC risk (OR 1.51, 95 % CI 0.90-2.53, and OR 1.44, 95 % CI 0.90-2.35, respectively). Restricting analyses to women >30 years further strengthened these associations.

CONCLUSIONS

While the small sample size limits inference, these findings show that altered DNA methylation at imprinted domains including IGF2/H19 and PEG1/MEST may mediate the association between HPV and ICC risk.

Protein composition of bronchoalveolar lavage fluid and airway surface liquid from newborn pigs

The airway mucosa and the alveolar surface form dynamic interfaces between the lung and the external environment. The epithelial cells lining these barriers elaborate a thin liquid layer containing secreted peptides and proteins that contribute to host defense and other functions. The goal of this study was to develop and apply methods to define the proteome of porcine lung lining liquid, in part, by leveraging the wealth of information in the Sus scrofa database of Ensembl gene, transcript, and protein model predictions. We developed an optimized workflow for detection of secreted proteins in porcine bronchoalveolar lavage (BAL) fluid and in methacholine-induced tracheal secretions [airway surface liquid (ASL)]. We detected 674 and 3,858 unique porcine-specific proteins in BAL and ASL, respectively. This proteome was composed of proteins representing a diverse range of molecular classes and biological processes, including host defense, molecular transport, cell communication, cytoskeletal, and metabolic functions. Specifically, we detected a significant number of secreted proteins with known or predicted roles in innate and adaptive immunity, microbial killing, or other aspects of host defense. In greatly expanding the known proteome of the lung lining fluid in the pig, this study provides a valuable resource for future studies using this important animal model of pulmonary physiology and disease.

SPLUNC1/BPIFA1 contributes to pulmonary host defense against Klebsiella pneumoniae respiratory infection

Epithelial host defense proteins comprise a critical component of the pulmonary innate immune response to infection. The short palate, lung, nasal epithelium clone (PLUNC) 1 (SPLUNC1) protein is a member of the bactericidal/permeability-increasing (BPI) fold-containing (BPIF) protein family, sharing structural similarities with BPI-like proteins. SPLUNC1 is a 25 kDa secretory protein that is expressed in nasal, oropharyngeal, and lung epithelia, and has been implicated in airway host defense against Pseudomonas aeruginosa and other organisms. SPLUNC1 is reported to have surfactant properties, which may contribute to anti-biofilm defenses. The objective of this study was to assess the importance of SPLUNC1 surfactant activity in airway epithelial secretions and to explore its biological relevance in the context of a bacterial infection model. Using cultured airway epithelia, we confirmed that SPLUNC1 is critically important for maintenance of low surface tension in airway fluids. Furthermore, we demonstrated that recombinant SPLUNC1 (rSPLUNC1) significantly inhibited Klebsiella pneumoniae biofilm formation on airway epithelia. We subsequently found that Splunc1(-/-) mice were significantly more susceptible to infection with K. pneumoniae, confirming the likely in vivo relevance of this anti-biofilm effect. Our data indicate that SPLUNC1 is a crucial component of mucosal innate immune defense against pulmonary infection by a relevant airway pathogen, and provide further support for the novel hypothesis that SPLUNC1 protein prevents bacterial biofilm formation through its ability to modulate surface tension of airway fluids.

An Anatomic Model for Use in Surgical Skills Training of Tracheotomy

Objective: The objective would be to design a low cost, reproducible anatomic model to simulate tracheotomy in the surgical skills training laboratory. The model was adapted from a base model used previously for verification of proficiency (VOP) assessment of cricothyrotomy by general surgery residents.

Method: The following materials were used: ventilator tubing, vessel loops, a 2x4x9-inch block of wood, red and white felt fabric, automotive ceiling headliner, cardboard, foam tape, adhesive spray, and foam. All materials were found easily at a local craft store or in medical discard.

Results: The model was assembled by securing ventilator tubing to a block of wood to represent the trachea. Thyroid and cricoid cartilages were fashioned and secured to ensure palpable landmarks. An anterior section of ventilator tubing was removed and replaced with foam tape to allow for a recyclable base. Finally, the thyroid and superficial tissue (including vessels and strap muscles) were assembled using headliner, felt, and vessel loops. After assembly was completed, four junior residents were able to successfully palpate each landmark, “ligate” vessels, identify and retract the thyroid isthmus, and perform a tracheostomy.

Conclusion: The model developed is a practical and reproducible anatomic model for simulation training of tracheotomy for otolaryngology residents and can be created utilizing inexpensive, readily available materials. In conjunction with a skills lab training session, this useful tool could play an important role in the overall evaluation of surgical competence.

Cystic fibrosis pigs develop lung disease and exhibit defective bacterial eradication at birth

Lung disease causes most of the morbidity and mortality in cystic fibrosis (CF). Understanding the pathogenesis of this disease has been hindered, however, by the lack of an animal model with characteristic features of CF. To overcome this problem, we recently generated pigs with mutated CFTR genes. We now report that, within months of birth, CF pigs spontaneously developed hallmark features of CF lung disease, including airway inflammation, remodeling, mucus accumulation, and infection. Their lungs contained multiple bacterial species, suggesting that the lungs of CF pigs have a host defense defect against a wide spectrum of bacteria. In humans, the temporal and causal relations between inflammation and infection have remained uncertain. To investigate these processes, we studied newborn pigs. Their lungs showed no inflammation but were less often sterile than controls. Moreover, after introduction of bacteria into their lungs, pigs with CF failed to eradicate bacteria as effectively as wild-type pigs. These results suggest that impaired bacterial elimination is the pathogenic event that initiates a cascade of inflammation and pathology in CF lungs. Our finding that pigs with CF have a host defense defect against bacteria within hours of birth provides an opportunity to further investigate CF pathogenesis and to test therapeutic and preventive strategies that could be deployed before secondary consequences develop.

Nest-site fidelity in parental male bluegill Lepomis macrochirus: spatial patterns and the influence of prior mating success

A 4 year mark-recapture study examined the pattern of nesting site fidelity of parental-type male bluegill Lepomis macrochirus. The study results indicated that iteroparous male L. macrochirus choose new nest sites near their own previously used sites. The scale of site fidelity varied, but generally males choose to renest within shoreline areas rather than specific or exact nest locations (94% within-year, 86% among-years). Iteroparous males also displayed no preference to nest in proximity to neighbouring males from previous colonies to suggest social fidelity. Contrary to expectation, manipulating males' reproductive success had no significant effect on the pattern or scale of male reproductive site fidelity.

PLUNC is a novel airway surfactant protein with anti-biofilm activity

Background

The PLUNC (“Palate, lung, nasal epithelium clone”) protein is an abundant secretory product of epithelia present throughout the conducting airways of humans and other mammals, which is evolutionarily related to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family. Two members of this family - the bactericidal/permeability increasing protein (BPI) and the lipopolysaccharide binding protein (LBP) - are innate immune molecules with recognized roles in sensing and responding to Gram negative bacteria, leading many to propose that PLUNC may play a host defense role in the human airways.

Methodology/Principal Findings

Based on its marked hydrophobicity, we hypothesized that PLUNC may be an airway surfactant. We found that purified recombinant human PLUNC greatly enhanced the ability of aqueous solutions to spread on a hydrophobic surface. Furthermore, we discovered that PLUNC significantly reduced surface tension at the air-liquid interface in aqueous solutions, indicating novel and biologically relevant surfactant properties. Of note, surface tensions achieved by adding PLUNC to solutions are very similar to measurements of the surface tension in tracheobronchial secretions from humans and animal models. Because surfactants of microbial origin can disperse matrix-encased bacterial clusters known as biofilms [1], we hypothesized that PLUNC may also have anti-biofilm activity. We found that, at a physiologically relevant concentration, PLUNC inhibited biofilm formation by the airway pathogen Pseudomonas aeruginosa in an in vitro model.

Conclusions/Significance

Our data suggest that the PLUNC protein contributes to the surfactant properties of airway secretions, and that this activity may interfere with biofilm formation by an airway pathogen.

Morbidity and mortality among a cohort of HIV-infected adults in a programme for community home-based care, in the Kilimanjaro Region of Tanzania (2003-2005)

Community home-based care (CHBC) plays an integral role in the care of HIV-infected patients living in resource-limited regions. A longitudinal cohort study has recently been conducted, in the Kilimanjaro Region of northern Tanzania, in order to identify the components of an effective CHBC programme. Structured questionnaires were administered to clients over two census rounds, one in October 2003-February 2004 and the other in January 2005-October 2005. In the second round, follow-up interviews were completed for 226 (87.9%) of the 257 clients included in the first round. The clients included in the first round had a median (range) age of 38 (20-66) years and 182 (75.2%) of them were female. Although only 27 (12.9%) of them were using antiretroviral therapy (ART) when first interviewed, 108 (44.6%) were taking trimethoprim-sulfamethoxazole (SXT) prophylaxis. By the time of the follow-up interviews, 102 (45.1%) of the clients included in the first round had died, giving a mortality of 51/100 person-years of observation. The primary cause of death for 87 (85.3%) of the clients who had died was respiratory and/or gastro-intestinal infection, and the most common contributory causes of death were malnutrition (81.4%) and anaemia (42.2%). On bivariable analysis, the following first-round conditions were found to be significantly associated with death by the second census round: weakness for >1 month [odds ratio (OR)=2.64; P=0.008]; oral thrush (OR=2.31; P=0.015); painful swallowing (OR=2.02; P=0.036); staying in bed for part of the day over most of the previous month (OR=1.94; P=0.017); fever for >1 month (OR=1.95; P=0.016); and severe bacterial infections (OR=1.80; P=0.036). The high mortality was associated with advanced, symptomatic HIV disease for which antiretroviral therapy was indicated. Clients who were in the advanced stages of HIV disease (as defined by the World Health Organization's criteria) in the first census round were significantly more likely to have died by the time of the second round than the other clients investigated (log-rank chi(2)=8.115; P=0.044). The high level of morbidity observed in this study, and the causes of mortality that were identified, emphasise the need for CHBC programmes to provide HIV-infected patients with improved access to basic resources such as SXT and isoniazid prophylaxis, clean water, oral rehydration therapy, and micronutrient supplementation, in addition to increased access to ART.

Low sensitivity of T-cell based detection of tuberculosis among HIV co-infected Tanzanian in-patients

OBJECTIVE

To evaluate the performance of QuantiFERON-TB GOLD (QFTG) in a resource-poor setting among patients with and without HIV infection.

DESIGN

Cross-sectional study.

SETTING

Two hospitals in Northern Tanzania.

SUBJECTS

Eighty three adult male and female inpatients.

INTERVENTION

All patients were screened for HIV infection and underwent tuberculin skin test (TST) and QFTG.

RESULTS

Eighty-three subjects were enrolled, and 29 (35%) of 83 were HIV-infected. QFTG yielded indeterminate results in 12 (22%; 95% CI 12%-34%) of 54 HIV-uninfected and 13 (45%; 95% CI 26%-64%) of 29 HIV-infected subjects (p = 0.0323). Among those with smear-positive pulmonary tuberculosis, TST was positive in 40 (100%; 95% CI 91%-100%) of 40 HIV-uninfected subjects compared with seven (54%; 95% CI 25%-81%) of 13 HIV-infected subjects (p < 0.0001), and QFTG was positive in 28 (70%; 95% CI 53%-83%) of 40 HIV-uninfected subjects compared with three (23%; 95% CI 5%-54%) of 13 HIV-infected subjects (p = 0.0029). Among medical inpatients at risk for latent tuberculosis infection, TST was positive in seven (50%) of 14 HIV-uninfected patients and three (19%) of 16 HIV-infected patients (p = 0.0701) and QFTG was positive among two (14%) of 14 HIV-uninfected patients and three (19%) of 16 HIV-infected patients (p = 0.7437).

CONCLUSIONS

The presence of HIV co-infection was associated with a significant reduction in sensitivity of both the TST (p < 0.0001) and QFTG (p = 0.0029) for the diagnosis of active M. tuberculosis infection. The high proportion of indeterminate QFTG and lack of sensitivity, particularly among HIV-infected patients, may limit its applicability in settings like Tanzania. Larger studies in resource-poor settings are required.

Microalbuminuria predicts overt proteinuria among patients with HIV infection

BACKGROUND

This study examines the association between microalbuminuria and the development of proteinuria among HIV-infected persons.

METHODS

A total of 948 subjects provided urine samples for albumin, protein and creatinine measurements semiannually. Microalbuminuria was defined as an albumin-to-creatinine ratio of >30 mg/g. Proteinuria was defined as a protein-to-creatinine ratio of > or =0.350 mg/mg. The progression from microalbuminuria to proteinuria was described.

RESULTS

At baseline, 69.4% of the subjects had no detectable proteinuria, 20.2% had microalbuminuria, and 10.4% had proteinuria. Subjects with microalbuminuria and proteinuria were more likely to be black (P=0.02), have lower CD4 cell counts (P=0.02 comparing subjects without abnormal urine protein excretion to subjects with microalbuminuria; P=0.0001 comparing subjects with microalbuminuria to subjects with proteinuria), and have a higher HIV RNA level (P=0.08 and 0.04, respectively). Among 658 subjects with normal urine protein, 82.7% continued to have no abnormality, 14.3% developed microalbuminuria, and 3.0% developed proteinuria. Subjects without baseline proteinuria (i.e. either normal protein excretion or microalbuminuria) who developed proteinuria were more likely to have microalbuminuria (P=0.001), a lower CD4 cell count (P=0.06), and a higher plasma HIV RNA (P=0.03) than those who did not progress to proteinuria. In multivariate analysis, only microalbuminuria remained associated with the development of proteinuria (odds ratio 2.9; 95% confidence interval 1.5, 5.5; P=0.001).

CONCLUSION

Microalbuminuria predicts the development of proteinuria among HIV-infected persons. Because proteinuria has been linked to poorer outcomes, strategies to affect microalbuminuria should be tested.

Missed opportunities for diagnosis of tuberculosis and human immunodeficiency virus co-infection in Moshi, Tanzania

SETTING

A community-based voluntary counseling and testing (VCT) center in Moshi, Tanzania.

OBJECTIVE

To compare rates of prior human immunodeficiency virus (HIV) testing among clients with and without previous tuberculosis (TB) treatment, and HIV seropositivity among those with and without current TB symptoms.

DESIGN

Cross-sectional study of consecutive clients presenting for initial testing; sociodemographic and clinical data were collected via a structured questionnaire. HIV status was compared among clients with or without three or more TB-related symptoms: weight loss, fever, cough, hemoptysis or night sweats.

RESULTS

Overall, 225 (3%) of 6583 VCT clients who responded to questions on previous TB treatment reported a history of TB, but only 34 (15%) reported previous HIV testing. This rate of HIV testing was not different from the rate among those clients without a history of TB (OR 0.77, P = 0.175). One hundred thirty-five (61%) clients with a history of TB were HIV-infected at VCT, compared with 17% of all clients. Of the total 6592 first-time testers who responded, 372 (6%) had at least three symptoms suggestive of TB at VCT. These symptoms were strongly associated with HIV seropositivity (OR 16.30, P < 0.001).

CONCLUSION

Missed opportunities for HIV diagnosis at the time of TB treatment appear frequent in this population, underscoring the need for integration of TB and HIV diagnostic services.

PLUNC is a secreted product of neutrophil granules

Airway epithelia and neutrophils are frequently recruited to release host defense factors in response to a variety of pulmonary pathogens. One abundant product of airway epithelia is palate, lung, nasal epithelium clone (PLUNC), a proposed innate immune protein expressed in submucosal glands and surface airway epithelia. In this study, we report the expression of PLUNC in human neutrophils, a previously unrecognized source of this protein. Immunoblots performed on polymorphonuclear cell (PMN) lysates and PMN subcellular fractions indicated that PLUNC was present in the specific granules of the neutrophil. Furthermore, secretion assays demonstrated that PLUNC protein was released by neutrophils upon stimulation with secretogogues, including formyl methionyl leucyl phenylalanine and the calcium ionophore A23187. Although recombinant PLUNC protein failed to exhibit antibacterial activity in our studies, its storage and secretion by a professional phagocytic cell support the hypothesis that PLUNC participates in an aspect of the inflammatory response that contributes to host defense. These studies suggest that PLUNC expression is less restricted than previously believed, and highlight new avenues of research for the study of PLUNC function.

Innate immune functions of the airway epithelium

The epithelium of the respiratory tract forms a large surface area that maintains intimate contact with the environment. Through the act of breathing, this mucosal surface encounters an array of pathogens and toxic particulates. In response to these challenges many strategies have evolved to protect the host. These include the barrier functions of the epithelium, cough, mucociliary clearance, resident professional phagocytes, and the secretion of a number of proteins and peptides with host defense functions. Thus, the surface and submucosal gland epithelium of the conducting airways is a constitutive primary participant in innate immunity. In addition, this tissue may serve the function of a secondary amplifier of innate immune responses following neurohumoral input, stimulation with cytokines from cells such as alveolar macrophages, or engagement of pattern recognition receptors. Here, we provide an overview of the airway epithelium's role in pulmonary innate immunity, especially in the context of bacterial and viral infections, emphasizing findings from human cells and selected animal models. We also provide examples of human disease states caused by impaired epithelial defenses in the lung.

Sociodemographic and clinical characteristics of clients presenting for HIV voluntary counselling and testing in Moshi, Tanzania

HIV voluntary counselling and testing (VCT) reduces high-risk sexual behaviour. Factors associated with HIV infection in VCT clients have not been well characterized in northern Tanzania. We prospectively surveyed 813 VCT clients in Moshi, Tanzania. Clients were administered a questionnaire on sociodemographic characteristics, sexual behaviour, and health status. Blood was taken for rapid HIV antibody testing. Factors associated with HIV seropositivity were identified using multivariate logistic regression analysis. Of 813 clients, the seroprevalence was 16.7%. The strongest associations with seropositivity were reporting diarrhoea (odds ratio [OR] 10.4, 95% confidence interval [CI] 3.6-29.9), an ill sexual partner (OR 6.3, 95% CI 3.0-12.9), or being a woman (OR 3.5, 95% CI 2.0-6.3). In a separate regression, the number of symptoms also predicted HIV infection (OR 2.1, 95% CI 1.6-2.6). VCT clients who tested positive had more HIV-related symptoms suggesting presentation at a later stage of HIV infection.

HIV-associated morbidity, mortality and diagnostic testing opportunities among inpatients at a referral hospital in northern Tanzania

Hospitalized patients with HIV infection are among the most likely to benefit from the expanding availability of anti-retroviral therapy in sub-Saharan Africa. Between 1990 and 2000, 3667 people known to be HIV-infected were admitted to Kilimanjaro Christian Medical Centre (KCMC) in Moshi, northen Tanzania. The level of inpatient mortality among these patients varied from 15%-21%, and the proportion of the HIV-infected patients admitted who were female increased significantly, from 45% at the start of the study period to 52% at the end (P <0.001). When the medical records for 1683 of the HIV-infected patients who had been admitted between 1996 and 2001 were reviewed, the most prevalent diagnoses on admission were found to be pulmonary tuberculosis (21%), malaria (14%) and gastro-enteritis/diarrhoea (12%) among the adults, and non-tubercular pulmonary infection (21%), pulmonary tuberculosis (19%) and gastro-enteritis/diarrhoea (12%) among the children. The crude odds ratios (OR) for inpatient death were greatest for adults presenting with meningitis [OR=3.7; 95% confidence interval (CI)=2.1-6.7], septicaemia (OR=2.9; CI=1.2-7.3) or renal disease (OR=2.6; CI=1.2-5.7), and mortality was higher for men than for women (OR=1.4; CI=1.1-1.8). A single-day, point-prevalence survey in September 2001, among the KCMC's inpatients, identified HIV infection in 21% of those surveyed, many (44%) of the patients found positive being previously unaware of their infection. HIV infection remains a major cause of hospitalization and mortality in Moshi. A policy of routine testing would increase the number of HIV infections detected, allowing improvements in case management and in the prevention of infection.

Genomics-based approaches to gene discovery in innate immunity

The completion of draft sequences of the human and mouse genomes offers many opportunities for gene discovery in the field of immunology through the application of the methods of computational genomics. One arm of the innate immune system includes the antimicrobial peptides that protect multicellular organisms from a diverse spectrum of microorganisms. The beta-defensins comprise an important family of mammalian antimicrobial peptides. To better define the beta-defensin gene family, we developed an approach to search genomic databases for conserved motifs present in the beta-defensin family using HMMER, a computational search tool based on hidden Markov models (HMMs), in combination with the basic local alignment search tool. The approach was first used to identify candidate second-exon coding regions, and later applied to finding associated first exons. This strategy discovered 28 new human and 43 new mouse beta-defensin genes in five syntenic chromosomal regions. Within each syntenic cluster, the gene sequences and organization were similar, suggesting that each cluster pair arose from a common ancestor and was retained because of conserved functions. These findings demonstrate an important proof-of-principle for a genome-wide search strategy to identify genes with conserved structural motifs. Such an approach may be readily adopted to address other questions of relevance to immunology.

Protease inhibitors are associated with a slowed progression of HIV-related renal diseases

AIMS

While angiotensin-con-verting enzyme inhibitors and zidovudine may improve the course of the most common HIV-related renal disease, HIV-associated nephropathy (HIVAN), the effect of anti-retroviral combination therapy on this and other HIV-related renal diseases has not been assessed. This study describes the clinical course of HIV-related renal diseases and the effect of protease inhibitors on their progression.

METHODS

This retrospective cohort study reviews the clinical course of 19 patients with a clinical or biopsy-proven diagnosis of HIVAN or other HIV-related renal diseases. Groups progressing and not progressing to ESRD were compared using longitudinal analyses to assess the association between creatinine clearance and clinical and therapeutic factors.

RESULTS

The cohort consisted of 16 African-Americans, 2 Caucasians and 1 Native American. Their modes of HIV infection were intravenous drug use (7), a history of men having sex with men (3) and heterosexual behavior (5). Patients were followed for a median of 16.6 months. Seven patients reached ESRD. Loss of creatinine clearance over time did not differ among genders, races, or patients with different modes of HIV infection. Longitudinal analyses demonstrated an association between protease inhibitors and prednisone and a slower decline in creatinine clearance in multivariable models (p = 0.04 and 0.003, respectively).

CONCLUSIONS

The epidemiology and clinical course of HIV-related renal diseases is more heterogeneous than previously described. This study suggests a benefit to the use of protease inhibitors and prednisone on the progression of these nephropathies.

Discovery of five conserved beta -defensin gene clusters using a computational search strategy

The innate immune system includes antimicrobial peptides that protect multicellular organisms from a diverse spectrum of microorganisms. beta-Defensins comprise one important family of mammalian antimicrobial peptides. The annotation of the human genome fails to reveal the expected diversity, and a recent query of the draft sequence with the blast search engine found only one new beta-defensin gene (DEFB3). To define better the beta-defensin gene family, we adopted a genomics approach that uses hmmer, a computational search tool based on hidden Markov models, in combination with blast. This strategy identified 28 new human and 43 new mouse beta-defensin genes in five syntenic chromosomal regions. Within each syntenic cluster, the gene sequences and organization were similar, suggesting each cluster pair arose from a common ancestor and was retained because of conserved functions. Preliminary analysis indicates that at least 26 of the predicted genes are transcribed. These results demonstrate the value of a genomewide search strategy to identify genes with conserved structural motifs. Discovery of these genes represents a new starting point for exploring the role of beta-defensins in innate immunity.

Addressing the challenges of adherence

Adherence to antiretroviral therapy is a crucial determinant of treatment success. Studies have unequivocally demonstrated the close association between adherence and plasma HIV RNA levels, CD4 cell counts, and mortality in patients with HIV infection and disease. Adherence levels of > or =95% are required to maintain virologic suppression. However, actual adherence rates are often far lower; most studies show that 40% to 60% of patients are <90% adherent. Adherence also tends to decrease over time. Patients offer a range of reasons for nonadherence, but the most frequently cited one is simply that they forget; other reasons include being away from home, being busy, or experiencing a change in daily routine. Additional barriers to adherence include psychiatric disorders, such as depression or substance use, uncertainty about the effectiveness of treatment and the consequences of poor adherence, regimen complexity, and treatment side effects. Several strategies can be employed in the effort to support patients' adherence, and all members of the multidisciplinary team should ideally employ these strategies in combination. Efforts should be made to educate and motivate patients, simplify treatment regimens and tailor them to individual lifestyles, prepare for and manage side effects, and address the concrete issues that may be a barrier to adherence. Recruiting an adherence monitor, providing memory aids to medication taking, and anticipating course corrections can also help patients achieve the adherence rates needed for successful treatment of HIV infection and disease.

Thymopoiesis in HIV-infected adults after highly active antiretroviral therapy

The thymus of HIV-seropositive patients can enlarge as CD4+ T cell counts increase on highly active anti-retroviral therapy (HAART). This may indicate development of new T cells or represent mature peripheral T cells recirculating to the thymus. To define the etiology of the enlargement, the thymuses of two HIV-infected individuals on HAART were biopsied. For more than 3 years before initiation of HAART, both patients (38 and 41 years of age) had documented CD4+ T lymphopenia. Peripheral blood samples were obtained to assess circulating CD4+ CD45RA+ CD62L+ T cells, which were thought to have recently developed in the thymus. Peripheral blood T cells from both patients and thymocytes from the second patient were also tested for levels of DNA episomes formed during T cell receptor gene rearrangement (T cell receptor rearrangement excision circles, TRECs). With HAART, peripheral blood CD4+ T cell counts increased from approximately 60/mm(3) to 552/mm(3) and 750/mm(3) for patients 1 and 2, respectively. Thymic biopsies from both patients showed normal thymus histology with active thymopoiesis. Percentages of peripheral blood CD4+ CD45RA+ CD62L+ T cells and quantitation of T cell TRECs also reflected active thymopoiesis in both patients. Thus, in these two HIV-seropositive adults examined after initiation of HAART, thymic enlargement represented active thymopoiesis. Thymopoiesis in adult AIDS patients may contribute to immune reconstitution even after prolonged CD4+ T lymphopenia.

Structured antiretroviral treatment interruptions in chronically HIV-1-infected subjects

The risks and benefits of structured treatment interruption (STI) in HIV-1-infected subjects are not fully understood. A pilot study was performed to compare STI with continuous highly active antiretroviral therapy (HAART) in chronic HIV-1-infected subjects with HIV-1 plasma RNA levels (VL) <400 copies per ml and CD4(+) T cells >400 per microl. CD4(+) T cells, VL, HIV-1-specific neutralizing antibodies, and IFN-gamma-producing HIV-1-specific CD8(+) and CD4(+) T cells were measured in all subjects. STIs of 1-month duration separated by 1 month of HAART, before a final 3-month STI, resulted in augmented CD8(+) T cell responses in all eight STI subjects (P = 0.003), maintained while on HAART up to 22 weeks after STI, and augmented neutralization titers to autologous HIV-1 isolate in one of eight subjects. However, significant decline of CD4(+) T cell count from pre-STI level, and VL rebound to pre-HAART baseline, occurred during STI (P = 0.001 and 0.34, respectively). CD4(+) T cell counts were regained on return to HAART. Control subjects (n = 4) maintained VL <400 copies per ml and stable CD4(+) T cell counts, and showed no enhancement of antiviral CD8(+) T cell responses. Despite increases in antiviral immunity, no control of VL was observed. Future studies of STI should proceed with caution.

Primary care for patients infected with human immunodeficiency virus: a randomized controlled trial

OBJECTIVE

To measure the impact of a teaching intervention and to compare process and outcomes of care for HIV-infected patients randomly assigned to a general medicine clinic (GMC) or an infectious disease clinic (IDC) for primary care.

DESIGN

Prospective, randomized, controlled trial.

SETTING

University hospital in Durham, NC.

PATIENTS

Two hundred fourteen consecutive HIV-infected patients presenting for primary care.

INTERVENTION

Physicians at the GMC received HIV-related training and evidence-based practice guidelines.

MEASUREMENTS

Utilization of services, health-related quality of life, preventive and screening measures, and antiretroviral use for one year.

RESULTS

At baseline GMC patients were more likely to be African American (85% vs 71%; P =.03) and had lower baseline CD4+ cell counts than IDC patients (262 +/- 269 vs 329 +/- 275; P =.05). A similar and high proportion of patients in both groups received appropriate preventive care services including Pneumocystis carinii pneumonia (PCP) prophylaxis, pneumococcal vaccination, and antiretroviral therapy. Screening for TB was more frequent in GMC (89% vs 68%; P =.001). In the year following randomization, GMC patients made more visits to the emergency department than IDC patients (1.6 +/- 3.0 vs 0.7 +/- 1.5; P =.05). Hospital use was higher for GMC patients with average length of stay 7.8 +/- 6.3 days compared to 5.7 +/- 3.8 days for IDC patients (P =.01). In analyses, which adjust for potential baseline imbalances, these differences remained.

CONCLUSIONS

Targeted education in GMC achieved similar provision of primary care for GMC patients, yet use of health care services was higher for this group. The delivery of adequate primary care is necessary but not sufficient to produce changes in health care utilization.

Overview of the effectiveness of triple combination therapy in antiretroviral-naive HIV-1 infected adults

AIM

To estimate the effectiveness of triple combination therapy in antiretroviral-naive adults.

METHODS

A systematic overview of results from clinical trials involving triple combination therapy with dual nucleoside reverse transcriptase inhibitors (NRTI) and: a protease inhibitor (PI triple); a non-nucleoside reverse transcriptase inhibitor (NNRTI triple); or a third NRTI (triple NUC). Data from 23 clinical trials involving 31 independent treatment groups, 19 unique antiretroviral regimens, and 3257 enrolled patients were included in this study.

RESULTS

Median log(10) baseline plasma HIV RNA and CD4 cell count over all trials averaged 4.69 (49,329 copies/ml) and 375 x 10(6) cells/l, respectively. The overall estimated percentage of patients with plasma HIV RNA < or = 400 copies/ml at 24 weeks was 64% [95% confidence interval (CI), 60 to 67%]. The percentages of patients with plasma HIV RNA < or = 50 copies/ml at 48 weeks by drug class were: PI triple, 46% (95% CI, 41 to 52%); NNRTI triple, 51% (95% CI, 43 to 59%); triple NUC, 45% (95% CI, 36 to 54%). The CD4 cell count increase over all trials at 24 and 48 weeks averaged +123 x 10(6) cells/l (95% CI, 111 x 10(6) to 135 x 10(6) cells/l) and +160 x 10(6) cells/l (95% CI, 146 x 10(6) to 175 x 10(6) cells/l), respectively and did not differ between drug classes. In multivariable regression analysis, neither baseline plasma HIV RNA level and CD4 cell count nor treatment regimen predicted plasma HIV RNA < or = 50 copies/ml at week 48. However, pill count was significantly negatively associated with plasma HIV RNA < or = 50 copies/ml at week 48 (P = 0.0085).

CONCLUSIONS

The results suggest that three drug regimens containing two NRTI with a PI, a NNRTI, or a third NRTI may provide comparable activity, and practical issues such as daily pill burden should be considered when choosing a treatment regimen.

Immune function in healthy inner-city children

The importance of investigating immunity in healthy children has been underscored in the last few years by studies of the immune pathology of childhood illnesses, including human immunodeficiency virus. This study reports both ennumerative and functional immune measures in healthy inner city children. A total of 152 of 207 children studied were completely heathy at the time of venipuncture and were included in this study. Laboratory immune batteries were completed (or begun) the same day as venipuncture. Relationships between age, gender, ethnicity, and immunity were then analyzed. We found that gender predicted both the absolute number and the percentage of T cells and helper cells and the percentage of natural killer cells. Total leukocyte counts and percentages of lymphocytes and granulocytes were related to ethnicity, as was the response to mitogen stimulation (concanavalin A and pokeweed mitogen) and phagocytic ability. In conclusion, age, gender, and ethnicity factors were found to contribute to differences in various immune measures in children and require further investigation.

Immunologic profile of human immunodeficiency virus-infected patients during viral remission and relapse on antiretroviral therapy

A dissociation between plasma human immunodeficiency virus (HIV) RNA levels and CD4(+) cell counts has been reported in patients experiencing viral relapse while receiving antiretroviral therapy. This study compared patients with stable CD4(+) lymphocytes during viral relapse while receiving treatment with patients who had sustained virus suppression. Plasma HIV RNA levels, lymphocyte immunophenotyping, and T cell receptor excision circle (TREC) levels were measured. Naive CD4(+) lymphocyte phenotype and TREC levels were not significantly different in patients with virus suppression or in those who had relapsed. However, CD8(+) lymphocyte activation, including the number and percentage of activated cells and CD38 antibody-binding capacity, was significantly elevated during viral relapse, compared with that in suppressed patients. By multivariable regression analyses, CD8(+) and CD4(+) lymphocyte activation were associated significantly with increasing plasma HIV RNA levels.

Influence of neurological level on immune function following spinal cord injury: a review

Due to the high incidence of lifelong infections in persons with spinal cord injury (SCI), the authors examined level of injury-related immune characteristics in a cohort of subjects with chronic SCI. Since the sympathetic nervous system and the endocrine system are known to be modulators of immune function, one possible explanation for heightened incidence of infections includes dysregulation of sympathetic outflow tracts in individuals with tetraplegia or high paraplegia. Natural killer cell cytotoxicity (NKCC) and bactericidal function of circulating neutrophils were assayed in a group of 10 individuals with chronic complete cervical SCI, a group of 8 individuals with paraplegia with injuries below the main sympathetic outflow (T-10 and below) and a group of 18 age- and sex-matched controls. In addition, a psychiatric assessment of depression was performed as well as assays of pituitary and adrenal functions. Analyses revealed no significant differences in immune function between all subjects with SCI combined and their matched controls. Further analyses stratifying based on presence or absence of sympathetic dysregulation revealed significantly impaired phagocytic ability and a trend toward reduced NKCC in the group with tetraplegia compared with their controls. Hormonal assays showed that dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DS) were higher in individuals with tetraplegia than controls, but no such differences were observed in individuals with paraplegia compared with their controls. The results of this study suggest that individuals sustaining complete cervical SCI experience alterations in immune function, while those with lesions at or below T-10 do not. These findings of level of injury related immune alteration could not be explained by mood differences. This paper is a review of previously published work and the authors' current thinking regarding increased acquisition of infections in this population.

The isolation of FOS-1, a gene encoding a putative two-component histidine kinase from Aspergillus fumigatus

In fungi, two-component histidine kinases are involved in response mechanisms to extracellular changes in osmolarity, resistance to dicarboximide fungicides, and cell-wall assembly. In the human opportunistic fungus, Candida albicans, each of the three histidine kinases plays a role in virulence. Here, we identify, for the first time, a gene, FOS-1, from the human pathogenic fungus Aspergillus fumigatus that predicts a protein with homology to two-component histidine kinases. The predicted FOS-1 protein is highly homologous to bacterial and other fungal histidine kinases in several functional domains, but is divergent at the amino- and carboxy-termini. A mutant lacking the FOS-1 locus, DeltaFOS-1, did not exhibit a detectable defect in either hyphal growth or morphology when grown on solid or liquid medium. However, in liquid medium, conidiophore development of the DeltaFOS-1 mutant was delayed. Compared to wild type, the DeltaFOS-1 strain was neither osmotically sensitive nor sensitive or resistant to a number of nondicarboximide antifungal drugs, but was highly resistant to dicarboximide fungicides and resistant to novozym 234, suggesting that FOS-1p may play a role in the regulation of cell-wall assembly.