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Of 319 children with invasive candidiasis, 67 (21%) transitioned from intravenous to enteral antifungal therapy. Eight (12%) transitioned back to intravenous antifungal therapy, one due to perceived treatment failure defined by clinical progression or worsening. Global treatment response at study completion was successful in 66 participants who transitioned to enteral therapy., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Transaminase and creatinine elevations have been well described in adults treated with remdesivir for COVID-19. It is hypothesized that a similar safety profile exists in children with COVID-19 treated with remdesivir, but available data are limited, especially in children < 12 months. The primary aim of this study was to determine the prevalence and timing of elevations in transaminases and creatinine in children with COVID-19 who were treated with remdesivir., Methods: This was a retrospective, observational cohort study including all pediatric patients admitted to a single, freestanding children's hospital who were positive for COVID-19 and received at least 1 dose of remdesivir between 1/1/2020 and 5/31/2022. Available baseline and peak transaminase and creatinine concentrations were evaluated. Multivariable logistic regression analysis was performed to identify risk factors for transaminase elevation., Results: A total of 180 patients met inclusion criteria. Creatinine elevation of any grade was noted in 16% and remained elevated only in those with underlying chronic kidney disease. Transaminase elevation of any grade was noted in 58% of patients and remained elevated in only 1%. Older age and critical respiratory disease were associated with higher risk of significant transaminase elevation, whereas non-Hispanic ethnicity was strongly associated with protection against significant transaminase elevation., Conclusions: In our cohort of hospitalized children with COVID-19 who were treated with remdesivir, most patients experienced only mild transaminitis and normal creatinine concentrations. A limited number of patients experienced laboratory abnormalities which were transient, suggesting a favorable safety profile for remdesivir use in pediatrics., (© 2024. The Author(s).)

Invasive fungal disease (IFD) remains a significant cause of morbidity and mortality in children undergoing transplantation. There is a growing armamentarium of novel antifungal agents recently approved for use or in late stages of clinical development. The overarching goal of this review is to discuss the mechanisms of action, spectrum of activity, stage of development, and pediatric-specific data for the following agents: encochleated amphotericin B deoxycholate, fosmanogepix, ibrexafungerp, isavuconazole, olorofim, opelconazole, oteseconazole, and rezafungin. Additionally, key drug attributes of these novel agents and their potential future therapeutic roles in pediatric transplant recipients are discussed., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Importance: Live vaccines (measles-mumps-rubella [MMR] and varicella-zoster virus [VZV]) have not been recommended after solid organ transplant due to concern for inciting vaccine strain infection in an immunocompromised host. However, the rates of measles, mumps, and varicella are rising nationally and internationally, leaving susceptible immunocompromised children at risk for life-threating conditions., Objective: To determine the safety and immunogenicity of live vaccines in pediatric liver and kidney transplant recipients., Design, Setting, and Participants: This cohort study included select pediatric liver and kidney transplant recipients who had not completed their primary MMR and VZV vaccine series and/or who displayed nonprotective serum antibody levels at enrollment between January 1, 2002, and February 28, 2023. Eligibility for live vaccine was determined by individual US pediatric solid organ transplant center protocols., Exposures: Exposure was defined as receipt of a posttransplant live vaccine. Transplant recipients received 1 to 3 doses of MMR vaccine and/or 1 to 3 doses of VZV vaccine., Main Outcome and Measure: Safety data were collected following each vaccination, and antibody levels were obtained at 0 to 3 months and 1 year following vaccination. Comparisons were performed using Mann-Whitney U test, and factors associated with development of postvaccination protective antibodies were explored using univariate analysis., Results: The cohort included 281 children (270 [96%] liver, 9 [3%] kidney, 2 [1%] liver-kidney recipients) from 18 centers. The median time from transplant to enrollment was 6.3 years (IQR, 3.4-11.1 years). The median age at first posttransplant vaccine was 8.9 years (IQR, 4.7-13.8 years). A total of 202 of 275 (73%) children were receiving low-level monotherapy immunosuppression at the time of vaccination. The majority of children developed protective antibodies following vaccination (107 of 149 [72%] varicella, 130 of 152 [86%] measles, 100 of 120 [83%] mumps, and 124 of 125 [99%] rubella). One year post vaccination, the majority of children who initially mounted protective antibodies maintained this protection (34 of 44 [77%] varicella, 45 of 49 [92%] measles, 35 of 42 [83%] mumps, 51 of 54 [94%] rubella). Five children developed clinical varicella, all of which resolved within 1 week. There were no cases of measles or rubella and no episodes of graft rejection within 1 month of vaccination. There was no association between antibody response and immunosuppression level at the time of vaccination., Conclusions and Relevance: The findings suggest that live vaccinations may be safe and immunogenic after solid organ transplant in select pediatric recipients and can offer protection against circulating measles, mumps, and varicella.

Background: Adjunctive diagnostic studies (aDS) are recommended to identify occult dissemination in patients with candidemia. Patterns of evaluation with aDS across pediatric settings are unknown., Methods: Candidemia episodes were included in a secondary analysis of a multicenter comparative effectiveness study that prospectively enrolled participants age 120 days to 17 years with invasive candidiasis (predominantly candidemia) from 2014 to 2017. Ophthalmologic examination (OE), abdominal imaging (AbdImg), echocardiogram, neuroimaging, and lumbar puncture (LP) were performed per clinician discretion. Adjunctive diagnostic studies performance and positive results were determined per episode, within 30 days from candidemia onset. Associations of aDS performance with episode characteristics were evaluated via mixed-effects logistic regression., Results: In 662 pediatric candidemia episodes, 490 (74%) underwent AbdImg, 450 (68%) OE, 426 (64%) echocardiogram, 160 (24%) neuroimaging, and 76 (11%) LP; performance of each aDS per episode varied across sites up to 16-fold. Longer durations of candidemia were associated with undergoing OE, AbdImg, and echocardiogram. Immunocompromised status (58% of episodes) was associated with undergoing AbdImg (adjusted odds ratio [aOR] 2.38; 95% confidence intervals [95% CI] 1.51-3.74). Intensive care at candidemia onset (30% of episodes) was associated with undergoing echocardiogram (aOR 2.42; 95% CI 1.51-3.88). Among evaluated episodes, positive OE was reported in 15 (3%), AbdImg in 30 (6%), echocardiogram in 14 (3%), neuroimaging in 9 (6%), and LP in 3 (4%)., Conclusions: Our findings show heterogeneity in practice, with some clinicians performing aDS selectively, potentially influenced by clinical factors. The low frequency of positive results suggests that targeted application of aDS is warranted., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: Osteoarticular infections (OAIs) in children pose significant risks if incorrectly managed. We introduced a clinical practice guideline (CPG) to decrease use of broad-spectrum and intravenous (IV) antibiotics for OAI treatment. The primary aims of our project were to decrease the percent of patients with empirical broad cephalosporin use to 10% and decrease IV antibiotic therapy on discharge to 20% while increasing narrow-spectrum oral antibiotic use to 80% within 24 months., Methods: We used quality improvement methodology to study patients diagnosed with OAIs. Interventions included multidisciplinary workgroup planning, CPG implementation, education, information technology, and stakeholder feedback. Outcome measures were the percentage of patients prescribed empirical broad-spectrum cephalosporins, percent discharged on IV antibiotics, and percent discharged on narrow-spectrum oral antibiotics. Process measures included percent of patients hospitalized on medicine service and infectious diseases consultation. Balancing measures included rates of adverse drug reactions, disease complications, length of stay, and readmission within 90 days. The impact of the interventions was assessed with run and control charts., Results: A total of 330 patients were included over 96 months. The percentage of patients with empirical broad cephalosporin coverage decreased from 47% to 10%, percent discharged on IV antibiotics decreased from 75% to 11%, and percent discharged on narrow-spectrum oral antibiotics increased from 24% to 84%. Adverse drug reactions decreased from 31% to 10%. Rates of complications, readmissions, and length of stay were unchanged., Conclusions: Through development and implementation of a CPG for OAI management, we demonstrated decreased use of empirical broad-spectrum antibiotics and improved definitive antibiotic management., (Copyright © 2023 by the American Academy of Pediatrics.)

Objective: Children require weight-based voriconazole doses proportionately larger than adults to achieve therapeutic serum trough concentrations (1-6 mcg/mL). The objective of this quality improvement project was to determine the initial dose, proportion of patients achieving target concentrations with initial dosing, and subsequent therapeutic drug monitoring and dose modifications needed to achieve and maintain therapeutic voriconazole concentrations in children., Methods: This retrospective study evaluated children aged <18 years treated with voriconazole during the study period. Dosing and therapeutic drug monitoring (TDM) values were collected and compared by age. Data are presented as median (IQR), unless otherwise stated., Results: Fifty-nine patients, aged 10.4 (3.7-14.7) years and 49% female, met inclusion criteria; 42 had at least 1 steady-state voriconazole serum trough concentration measured. Twenty-one of 42 (50%) achieved the target concentration at the first steady-state measurement. An additional 13 of 42 (31%) achieved the target following 2 to 4 dose modifications. The dose required to first achieve a value in the target range was 22.3 (18.0-27.1) mg/kg/day in children aged <12 years and 12.0 (9.8-14.0) mg/kg/day in children aged ≥12 years. After reaching the target, 59% and 81% of repeated steady-state measurements were in the therapeutic range in patients aged <12 years and ≥12 years, respectively., Conclusions: Reaching therapeutic voriconazole serum trough concentrations required doses larger than currently recommended by the American Academy of Pediatrics. Multiple dose adjustments and TDM measurements were required to achieve and maintain therapeutic voriconazole serum concentrations., Competing Interests: Disclosures. The authors declare no conflicts or financial interest in any product or service mentioned in the manuscript, including grants, equipment, medications, employment gifts, and honoraria. The authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the analysis., (Copyright. Pediatric Pharmacy Association. All rights reserved. For permissions, email: membership@pediatricpharmacy.org 2023.)

Background: Diagnosis of invasive candidiasis (IC) relies on insensitive cultures; the relative utility of fungal biomarkers in children is unclear., Methods: This multinational observational cohort study enrolled patients aged >120 days and <18 years with concern for IC from 1 January 2015 to 26 September 2019 at 25 centers. Blood collected at onset of symptoms was tested using T2Candida, Fungitell (1→3)-β-D-glucan, Platelia Candida Antigen (Ag) Plus, and Platelia Candida Antibody (Ab) Plus assays. Operating characteristics were determined for each biomarker, and assays meeting a defined threshold considered in combination. Sterile site cultures were the reference standard., Results: Five hundred participants were enrolled at 22 centers in 3 countries, and IC was diagnosed in 13 (2.6%). Thirteen additional blood specimens were collected and successfully spiked with Candida species, to achieve a 5.0% event rate. Valid T2Candida, Fungitell, Platelia Candida Ag Plus, and Platelia Candida Ab Plus assay results were available for 438, 467, 473, and 473 specimens, respectively. Operating characteristics for T2Candida were most optimal for detecting IC due to any Candida species, with results as follows: sensitivity, 80.0% (95% confidence interval, 59.3%-93.2%), specificity 97.1% (95.0%-98.5%), positive predictive value, 62.5% (43.7%-78.9%), and negative predictive value, 98.8% (97.2%-99.6%). Only T2Candida and Platelia Candida Ag Plus assays met the threshold for combination testing. Positive result for either yielded the following results: sensitivity, 86.4% (95% confidence interval, 65.1%- 97.1%); specificity, 94.7% (92.0%-96.7%); positive predictive value, 47.5% (31.5%-63.9%); and negative predictive value, 99.2% (97.7%-99.8%)., Conclusions: T2Candida alone or in combination with Platelia Candida Ag Plus may be beneficial for rapid detection of Candida species in children with concern for IC., Clinical Trials Registration: NCT02220790., Competing Interests: Potential conflicts of interest. B. T. F. receives funding from the Food and Drug Administration, Pfizer, and Merck and serves as a paid chair of a data and safety monitoring board (DSMB) for Astellas. R. H. serves on advisory boards for Quidel and Inflammatix; receives ASM Press book royalties (personal payments); and serves as a member of the board of directors for the Clinical Laboratories Standards Institute and as immediate past president for the Pan-American Society for Clinical Virology (both unpaid). T. E. Z. provides consultant services for T2 Biosystems and Nabriva Therapeutics. D. E. Y.’s institution receives funding from Merck, Astellas, Marion Merrel Dow Fund, Viracor-Eurofins (laboratory testing services to institution for investigator-initiated research), and Chimerix. D. E. Y. is now employed by the National Institute of Allergy and Infectious Diseases, NIH, which has paid for conference registration and fees, but this research was conducted while he was employed by Children’s Mercy Kansas City and the University of Missouri–Kansas City School of Medicine. D. E. Y. also reports serving as unpaid technical advisor to nonprofit organizations Cover the Globe and Maipelo Trust, which provide human immunodeficiency virus services to migrant or displaced children and families in Botswana. A. R. H. has patent 10,160,974 issued (Engineered cytokine- and chemokine-expressing Candida albicans strains and methods of use; no royalties collected); reports grant support from the NIH (grant K08DE026189 from the National Institute of Dental and Craniofacial Research and NIH pass-through via Duke grants [DOMINIC]); and reports serving on the Central Review Board for Non-Invasive Diagnosis of Pediatric Pulmonary Invasive Mold infections (DOMINIC) (unpaid). L. D. I. received institutional support for contracted clinical research from Astellas, Merck, Takeda, Ansun Biopharma, and Viracor-Eurofins; is a paid consultant for Takeda and paid chair of a DSMB for Merck; and serves as president of The International Society for Heart and Lung Transplantation. W. J. M. receives support from Adagio Therapeutics, Ansun Biopharma, Astellas, AstraZeneca, Eli Lilly, Enanta Pharmaceuticals, Janssen, Karius, Merck, Genentech, Gilead, Moderna, Melinta, Nabriva, Tetraphase, and Seqirus; reports consulting fees from Seqirus (to institution), the US Attorney’s Office, Southern District of Illinois (to self), McQuade Blasko Law Offices (to self), Finley Law Firm (to self), Doherty & Progar (to self), Phelan, Tucker, Mullen, Walker, Tucker, Gelman (to self), and Bailes, Craig, Yon & Sellards (to self); and reports participation on DSMB or advisory boards for Adagio Therapeutics and ProventionBio (payments to self). E. R. receives funding from Merck Sharp & Dohme (MSD), Merck, Pfizer, and Gilead; reports consulting fees from MSD and Pfizer (paid to institution); reports honoraria for lectures paid to their institution from Pfizer, MSD, and Gilead; reports travel support/payment of registration from Vianex, Pfizer, and MSD; and reports participation on advisory board(s) for MSD and Pfizer. P. K. S. reports grants from Astellas and Merck (to institution for work as clinical trial site). D. B. was a consultant for Teleflex. D. B. reports consulting fees from Precision Health (consulting agreement as of August 2021), for providing advice on the selection of polymerase chain reaction panels for outpatients in long-term care facilities and educating the Medical Science Liason team on their use) and Karius Diagnostics (where D. B. has been employed full time since 28 June 2021, as medical director in the Medical Affairs Division); Karius offers metagenomic next-generation sequencing for pathogens from plasma). As a full-time Karius employee, D. B. has the option to purchase stocks in the future during the initial public offering (the timing of the initial public offering is not yet known). D. B. continue to have a faculty appointment at Johns Hopkins All Children’s Hospital and hospital privileges (per diem). N. H. was a consultant for Moderna; receives funding from NIH, the Centers for Disease Control and Prevention, Quidel, and Sanofi; and serves as a Pediatric Infectious Diseases Society board member. G. M. receives funding from Astellas. P. S. P. receives support from Pfizer (research grant), Grifols, CSL Behring, Takeda, and Gilead (education and research grants); reports payment/honoraria from Pfizer and Gilead and payment for expert testimony from Gilead; reports participation on DSMB or an advisory board for Pfizer. C. M. S. reports receiving an NIH grant for the BIOPIC study, during the conduct of the study. M. G. reports NIH funding, outside the submitted work; receives royalties for being a textbook editor for Elsevier; reports personal consulting fees from ITB-Med; reports a personal honorarium for a lecture from Medscape; reports personal payments for serving on an advisory board for ATARA Biotherapeutics; and serves on the DSMB and as a consultant for Bristol Myers Squibb. S. B. H. reports honoraria for lectures on coronavirus disease 19 in Texas and office infection control from the Centers for Disease Control and Prevention. W. J. S. serves on the scientific advisory board of Sfunga (personal payments). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: The objective of this study was to measure the recovery of routine pediatric immunization after a period of reduced vaccine administrations in the early weeks of the COVID-19 pandemic., Methods: We recorded data on vaccines administered in Children's Wisconsin primary care or urgent care clinics from January 2019 through December 2020 and aggregated data by date and insurance type., Results: During the gradual reopening period after week 21 in 2020, vaccine administration returned to prepandemic levels for children with commercial insurance but remained below baseline rates until the end of 2020 for children with Medicaid insurance., Discussion: The decline in pediatric vaccination in 2020 disproportionately affected children with Medicaid insurance., (Copyright© Board of Regents of the University of Wisconsin System and The Medical College of Wisconsin, Inc.)

Objectives: A quality improvement approach was used to increase pediatric liver transplant recipient live and inactive vaccination rates by assessing titers and recommending vaccinations., Methods: A new screening and immunization process for both live and inactive vaccines was discussed with families at their annual visit. Antibody titers for varicella, measles, mumps, rubella, Haemophilus influenzae type B, hepatitis A, and hepatitis B were obtained. Specific criteria were developed for live virus vaccination candidacy. Vaccines were recommended based on patient titers and vaccination candidacy criteria. Surveillance for adverse effects to live vaccines was performed. Repeat titers were obtained approximately 1-month post-vaccine administration., Results: After PDSA cycle 1, 99% (71/72) of pediatric liver transplant patients had titers obtained. Live vaccines were recommended for 32 patients and 16 (50%) were vaccinated. Inactive vaccines were recommended to 64 patients, and 31 (48%) were vaccinated. Eight of 13 (62%) patients with follow-up titers achieved immunity for inactive vaccines. Zero patients had an adverse reaction to any live vaccine. Ten of 12 (83%) patients with follow-up titers achieved immunity from live vaccines. The most common barriers to receive live vaccines included not scheduling appointment with primary care provider (n = 3) and "non-vaccinators" (n = 3)., Conclusions: Administering live and inactive vaccines to select pediatric liver transplant patients appears to be safe and effective in our studied population. For PDSA cycle 2, we will continue our current practice and consider offering vaccines in transplant clinic, since this was a barrier to vaccination identified during PDSA cycle 1., (© 2021 Wiley Periodicals LLC.)

Background: Blastomycosis, an endemic mycosis of immunocompetent individuals, is typically seen after exposure to waterways within rural wooded regions. It is not considered a disease of urban environments. Infection can be solely pneumonic or disseminate to skin, bone or central nervous system. Unknown factors influence disease acquisition and severity in children., Methods: We analyzed acquisition risks and disease characteristics of blastomycosis in children seen at a tertiary care center from 1998 to 2018 to identify potential exposure sources, measure disease severity and assess the effect of race upon disease severity., Results: Of 64 infected children, mean age was 12.9 years, with median time to diagnosis 38.5 days. About 72% were male, 38% resided in urban counties and 50% had typical environmental exposure. Isolated pulmonary infection occurred in 33 (52%). The remainder had evidence of dissemination to skin (N = 13), bone (N = 16; 7 clinically silent) and cranium (N = 7; 3 clinically silent). Infection was moderate/severe in 19 (30%). Two children (3%) died. About 79% of children with moderate/severe disease (P = 0.008) and 71% of urban children (P = 0.007) lacked typical environmental exposure. Comparing children from urban counties to other residences, 63% versus 5% were black (P < 0.001) and 71% versus 35% developed extrapulmonary dissemination (P = 0.006). Moderate/severe disease was seen in 7/17 (42%) black children but only 12/47 (26%) children of other races (P = 0.23)., Conclusions: Blastomycosis, can be endemic in urban children in the absence of typical exposure history, have frequent, sometimes clinically silent, extrapulmonary dissemination and possibly produces more severe disease in black children., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Invasive candidiasis is the most common invasive fungal disease in children and adolescents, but there are limited pediatric-specific antifungal effectiveness data. We compared the effectiveness of echinocandins to triazoles or amphotericin B formulations (triazole/amphotericin B) as initial directed therapy for invasive candidiasis., Methods: This multinational observational cohort study enrolled patients aged >120 days and <18 years with proven invasive candidiasis from January 1, 2014, to November 28, 2017, at 43 International Pediatric Fungal Network sites. Primary exposure was initial directed therapy administered at the time qualifying culture became positive for yeast. Exposure groups were categorized by receipt of an echinocandin vs receipt of triazole/amphotericin B. Primary outcome was global response at 14 days following invasive candidiasis onset, adjudicated by a centralized data review committee. Stratified Mantel-Haenszel analyses estimated risk difference between exposure groups., Results: Seven-hundred and fifty invasive candidiasis episodes were identified. After exclusions, 541 participants (235 in the echinocandin group and 306 in the triazole/amphotericin B group) remained. Crude failure rates at 14 days for echinocandin and triazole/amphotericin B groups were 9.8% (95% confidence intervals [CI]: 6.0% to 13.6%) and 13.1% (95% CI: 9.3% to 16.8%), respectively. The adjusted 14-day risk difference between echinocandin and triazole/amphotericin B groups was -7.1% points (95% CI: -13.1% to -2.4%), favoring echinocandins. The risk difference was -0.4% (95% CI: -7.5% to 6.7%) at 30 days., Conclusions: In children with invasive candidiasis, initial directed therapy with an echinocandin was associated with reduced failure rate at 14 days but not 30 days. These results may support echinocandins as initial directed therapy for invasive candidiasis in children and adolescents., Clinical Trials Registration: NCT01869829., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Candida species cause serious infections requiring prolonged and sometimes toxic therapy. Antimicrobial proteins, such as chemokines, hold great interest as potential additions to the small number of available antifungal drugs. Metamorphic proteins reversibly switch between multiple different folded structures. XCL1 is a metamorphic, antimicrobial chemokine that interconverts between the conserved chemokine fold (an α-β monomer) and an alternate fold (an all-β dimer). Previous work has shown that human XCL1 kills C. albicans but has not assessed whether one or both XCL1 folds perform this activity. Here, we use structurally locked engineered XCL1 variants and Candida killing assays, adenylate kinase release assays, and propidium iodide uptake assays to demonstrate that both XCL1 folds kill Candida , but they do so via different mechanisms. Our results suggest that the alternate fold kills via membrane disruption, consistent with previous work, and the chemokine fold does not. XCL1 fold-switching thus provides a mechanism to regulate the XCL1 mode of antifungal killing, which could protect surrounding tissue from damage associated with fungal membrane disruption and could allow XCL1 to overcome candidal resistance by switching folds. This work provides inspiration for the future design of switchable, multifunctional antifungal therapeutics.

Gammaherpesviruses establish lifelong infection and are associated with a variety of cancers, including B cell lymphomas. These viruses manipulate the B cell differentiation process to establish lifelong infection in memory B cells. Specifically, gammaherpesviruses infect naive B cells and promote entry of both infected and uninfected naive B cells into germinal centers, where the virus usurps rapid proliferation of germinal center B cells to exponentially increase its cellular latent reservoir. In addition to facilitating the establishment of latent infection, germinal center B cells are thought to be the target of viral transformation. In this study, we have uncovered a novel proviral role of host interleukin 17A (IL-17A), a well-established antibacterial and antifungal factor. Loss of IL-17A signaling attenuated the establishment of chronic gammaherpesvirus infection and gammaherpesvirus-driven germinal center response in a route of inoculation-dependent manner. Further, IL-17A treatment directly supported gammaherpesvirus reactivation and de novo lytic infection. This study is the first demonstration of a multifaceted proviral role of IL-17 signaling. IMPORTANCE Gammaherpesviruses establish lifelong infections in a majority of humans and are associated with B cell lymphomas. IL-17A is a host cytokine that plays a well-established role in the clearance of bacterial and fungal infections; however, the role of IL-17A in viral infections is poorly understood. In this study, we show that IL-17A signaling promoted the establishment of chronic gammaherpesvirus infection following the mucosal route of infection, viral lytic replication, and reactivation from latency. Thus, our study unveils a novel proviral role of IL-17A signaling in gammaherpesvirus infection., (Copyright © 2021 Jondle et al.)

Candida albicans is a commensal organism that causes life-threatening or life-altering opportunistic infections. Treatment of Candida infections is limited by the paucity of antifungal drug classes. Naturally occurring antimicrobial peptides are promising agents for drug development. CCL28 is a CC chemokine that is abundant in saliva and has in vitro antimicrobial activity. In this study, we examine the in vivo Candida killing capacity of CCL28 in oropharyngeal candidiasis as well as the spectrum and mechanism of anti- Candida activity. In the mouse model of oropharyngeal candidiasis, application of wild-type CCL28 reduces oral fungal burden in severely immunodeficient mice without causing excessive inflammation or altering tissue neutrophil recruitment. CCL28 is effective against multiple clinical strains of C. albicans Polyamine protein transporters are not required for CCL28 anti- Candida activity. Both structured and unstructured CCL28 proteins show rapid and sustained fungicidal activity that is superior to that of clinical antifungal agents. Application of wild-type CCL28 to C. albicans results in membrane disruption as measured by solute movement, enzyme leakage, and induction of negative Gaussian curvature on model membranes. Membrane disruption is reduced in CCL28 lacking the functional C-terminal tail. Our results strongly suggest that CCL28 can exert antifungal activity in part via membrane permeation and has potential for development as an anti- Candida therapeutic agent without inflammatory side effects., (Copyright © 2020 American Society for Microbiology.)

Antimicrobial peptides (AMPs) are a class of molecules which generally kill pathogens via preferential cell membrane disruption. Chemokines are a family of signaling proteins that direct immune cell migration and share a conserved α-β tertiary structure. Recently, it was found that a subset of chemokines can also function as AMPs, including CCL20, CXCL4, and XCL1. It is therefore surprising that machine learning based analysis predicts that CCL20 and CXCL4's α-helices are membrane disruptive, while XCL1's helix is not. XCL1, however, is the only chemokine known to be a metamorphic protein which can interconvert reversibly between two distinct native structures (a β-sheet dimer and the α-β chemokine structure). Here, we investigate XCL1's antimicrobial mechanism of action with a focus on the role of metamorphic folding. We demonstrate that XCL1 is a molecular "Swiss army knife" that can refold into different structures for distinct context-dependent functions: whereas the α-β chemokine structure controls cell migration by binding to G-Protein Coupled Receptors (GPCRs), we find using small angle X-ray scattering (SAXS) that only the β-sheet and unfolded XCL1 structures can induce negative Gaussian curvature (NGC) in membranes, the type of curvature topologically required for membrane permeation. Moreover, the membrane remodeling activity of XCL1's β-sheet structure is strongly dependent on membrane composition: XCL1 selectively remodels bacterial model membranes but not mammalian model membranes. Interestingly, XCL1 also permeates fungal model membranes and exhibits anti- Candida activity in vitro , in contrast to the usual mode of antifungal defense which requires Th17 mediated cell-based responses. These observations suggest that metamorphic XCL1 is capable of a versatile multimodal form of antimicrobial defense.

Nontuberculous mycobacteria (NTM) infect children with increasing frequency worldwide. Using blood and lymph node tissue from children with NTM lymphadenitis, and uninfected lymph node tissue from community controls, we evaluated helper T (TH) cells in functional assays of TH1/TH17 differentiation and measured the concentration of their associated cytokines at the site of infection. Circulating TH cells from infected children were attenuated in their TH1/TH17 differentiation capacity and expressed less interferon γ and interleukin 17 after polyclonal stimulation. Similar differences were observed at the site of infection, where most cytokine concentrations were unchanged relative to controls. Our data are consistent with a model wherein TH1/TH17 differentiation is attenuated in NTM-infected children., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Invasive fungal infections are a serious cause of morbidity and mortality in patients with hematologic malignancies. Conidiobolus species are molds within the order Entomophthorales and may disseminate to become rapidly fatal in immunocompromised individuals. This species of fungal infections are often multidrug resistant (MDR) and present unique therapeutic challenges. Reports of Conidiobolus infections are rare in pediatric oncology. We report the successful treatment of an adolescent male with B-cell lymphoblastic leukemia and MDR invasive sinopulmonary Conidiobolus infection with emphasis on early and aggressive neutrophil support with surgical debridement. The strategies described could be applied to other MDR fungal infections.

The chemokine CCL28 is constitutively expressed in mucosal tissues and is abundant in low-salt mucosal secretions. Beyond its traditional role as a chemoattractant, CCL28 has been shown to act as a potent and broad-spectrum antimicrobial agent with particular efficacy against the commensal fungus and opportunistic pathogen Candida albicans. However, the structural features that allow CCL28 to perform its chemotactic and antimicrobial functions remain unknown. Here, we report the structure of CCL28, solved using nuclear magnetic resonance spectroscopy. CCL28 adopts the canonical chemokine tertiary fold, but also has a disordered C-terminal domain that is partially tethered to the core by a non-conserved disulfide bond. Structure-function analysis reveals that removal of the C-terminal tail reduces the antifungal activity of CCL28 without disrupting its structural integrity. Conversely, removal of the non-conserved disulfide bond destabilizes the tertiary fold of CCL28 without altering its antifungal effects. Moreover, we report that CCL28 unfolds in response to low pH but is stabilized by the presence of salt. To explore the physiologic relevance of the observed structural lability of CCL28, we investigated the effects of pH and salt on the antifungal activity of CCL28 in vitro. We found that low pH enhances the antifungal potency of CCL28, but also that this pH effect is independent of CCL28's tertiary fold. Given its dual role as a chemoattractant and antimicrobial agent, our results suggest that changes in the salt concentration or pH at mucosal sites may fine-tune CCL28's functional repertoire by adjusting the thermostability of its structure., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: The development and implementation of an antimicrobial lock therapy guideline at a large pediatric hospital are described., Summary: Central venous access devices (CVADs) are essential in the medical management of patients requiring long-term total parenteral nutrition, chemotherapy, or hemodialysis. However, the use of a CVAD carries a significant risk of the development of central line-associated bloodstream infection (CLABSI). Antimicrobial lock therapy is indicated for patients with CLABSIs who have no signs of exit site or tunnel infection and for whom catheter salvage is a goal. An antimicrobial lock therapy guideline was developed and implemented at a large pediatric hospital by an interprofessional team consisting of providers specializing in CVAD care. Development and implementation of the guideline included a needs assessment, a literature review, determination of patient selection criteria, addition of compounding formulations, development of administration techniques, and education. In all 10 instances of lock therapy in the 18 months after guideline implementation, the criteria for use were met; in 60% of those instances, patients received care from an infectious diseases physician. Each of the available lock solutions was used at least once during the 18-month period., Conclusion: Overall, implementation of a guideline on administration of antimicrobial lock therapy was successful. Nine patients received antimicrobial lock therapy in the 18 months after policy implementation; although 2 had their line removed (1 due to repeated line infections), neither required line replacement., (Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.)

Candida albicans is a dimorphic commensal fungus that causes severe oral infections in immunodeficient patients. Invasion of C. albicans hyphae into oral epithelium is an essential virulence trait. Interleukin-17 (IL-17) signaling is required for both innate and adaptive immunity to C. albicans During the innate response, IL-17 is produced by γδ T cells and a poorly understood population of innate-acting CD4 + αβ T cell receptor (TCRαβ) + cells, but only the TCRαβ + cells expand during acute infection. Confirming the innate nature of these cells, the TCR was not detectably activated during the primary response, as evidenced by Nur77 eGFP mice that report antigen-specific signaling through the TCR. Rather, the expansion of innate TCRαβ + cells was driven by both intrinsic and extrinsic IL-1R signaling. Unexpectedly, there was no requirement for CCR6/CCL20-dependent recruitment or prototypical fungal pattern recognition receptors. However, C. albicans mutants that cannot switch from yeast to hyphae showed impaired TCRαβ + cell proliferation and Il17a expression. This prompted us to assess the role of candidalysin, a hyphal-associated peptide that damages oral epithelial cells and triggers production of inflammatory cytokines including IL-1. Candidalysin-deficient strains failed to up-regulate Il17a or drive the proliferation of innate TCRαβ + cells. Moreover, candidalysin signaled synergistically with IL-17, which further augmented the expression of IL-1α/β and other cytokines. Thus, IL-17 and C. albicans , via secreted candidalysin, amplify inflammation in a self-reinforcing feed-forward loop. These findings challenge the paradigm that hyphal formation per se is required for the oral innate response and demonstrate that establishment of IL-1- and IL-17-dependent innate immunity is induced by tissue-damaging hyphae., (Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Invasive fungal diseases are important clinical problems that are often complicated by severe illness and therefore the inability to use invasive measures to definitively diagnose the disease. Tests for a range of fungal biomarkers that do not require an invasive sample-collection procedure have been incorporated into adult clinical practice, but pediatric data and pediatric-specific recommendations for some of these diagnostic tools are lacking. In this review, we summarize the published literature and contemporary strategies for using the biomarkers galactomannan, (1→3)-β-d-glucan, Candida mannan antigen and anti-mannan antibody, and fungal polymerase chain reaction for diagnosing invasive fungal disease in children. Data on biomarker use in neonates and children with cancer, history of hematopoietic stem cell transplant, or primary immunodeficiency are included. Fungal biomarker tests performed on blood, other body fluids, or tissue specimens represent promising adjuncts to the diagnostic armamentarium in populations with a high prevalence of invasive fungal disease, but substantial gaps exist in the correct use and interpretation of these diagnostic tools in pediatric patients., (© The Author 2017. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Mycobacteria and Candida species include significant human pathogens that can cause localized or disseminated infections. Although these organisms may appear to have little in common, several shared pathways of immune recognition and response are important for both control and infection-related pathology. In this article, we compare and contrast the innate and adaptive components of the immune system that pertain to these infections in humans and animal models. We also explore a relatively new concept in the mycobacterial field: biological commensalism. Similar to the well-established model of Candida infection, Mycobacteria species colonize their human hosts in equilibrium with the immune response. Perturbations in the immune response permit the progression to pathologic disease at the expense of the host. Understanding the immune factors required to maintain commensalism may aid with the development of diagnostic and treatment strategies for both categories of pathogens., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Study Objective: To describe our experience with voriconazole in three patients younger than 2 years using an optimized dosing strategy for voriconazole that incorporates intensive therapeutic drug monitoring (TDM)., Design: Case series., Setting: Large pediatric hospital., Patients: Three patients younger than 2 years who received voriconazole therapy and had serum trough concentrations measured between January 1, 2010, and October 31, 2015., Measurements and Main Results: A clinical practice guideline developed at our institution was used to standardize initial dosing, appropriate use and timing of TDM, and dosage modifications based on TDM. TDM was used to guide dosing to achieve a target voriconazole serum trough concentration of 2-6 μg/ml. Voriconazole samples were assayed by using a high-performance liquid chromatography analytical method with solid-phase extraction. Initial dosages for the three patients were 9 mg/kg intravenously every 12 hours (one patient) and 9 mg/kg enterally twice/day (two patients). Multiple dose escalations and a more frequent dosing interval were required to achieve trough concentrations within the target range. The final dosages were 12 mg/kg intravenously every 8 hours, 17.7 mg/kg enterally 3 times/day, and 8.5 mg/kg enterally 3 times/day, respectively. In addition to voriconazole trough concentrations, TDM included evaluations for drug toxicities. Visual, neurologic, or hepatic adverse effects were not encountered in the three patients., Conclusion: Our data support higher initial doses and perhaps a 3 times/day dosing schedule to achieve voriconazole serum concentrations in the target range for children younger than 2 years. Implementation of a clinical practice guideline with the participation of pharmacists specializing in pharmacokinetics allows for effective use of voriconazole in young children., (© 2016 Pharmacotherapy Publications, Inc.)

Candida albicans is normally a commensal fungus of the human mucosae and skin, but it causes life-threatening systemic infections in hospital settings in the face of predisposing conditions, such as indwelling catheters, abdominal surgery, or antibiotic use. Immunity to C. albicans involves various immune parameters, but the cytokine interleukin-17A (IL-17A) (also known as IL-17) has emerged as a centrally important mediator of immune defense against both mucosal and systemic candidiasis. Conversely, IL-17A has been suggested to enhance the virulence of C. albicans, indicating that it may exert detrimental effects on pathogenesis. In this study, we hypothesized that a C. albicans strain expressing IL-17A would exhibit reduced virulence in vivo. To that end, we created a Candida-optimized expression cassette encoding murine IL-17A, which was transformed into the DAY286 strain of C. albicans. Candida-derived IL-17A was indistinguishable from murine IL-17A in terms of biological activity and detection in standard enzyme-linked immunosorbent assays (ELISAs). Expression of IL-17A did not negatively impact the growth of these strains in vitro. Moreover, the IL-17A-expressing C. albicans strains showed significantly reduced pathogenicity in a systemic model of Candida infection, mainly evident during the early stages of disease. Collectively, these findings suggest that IL-17A mitigates the virulence of C. albicans., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

IL-17 protects against pathogens by acting on nonhematopoietic cells to induce neutrophil recruitment through upregulation of chemokines and G-CSF. IL-17- and Th17-deficient humans and mice are susceptible to mucosal Candida albicans infections, linked to impaired neutrophil responses. IL-17 production is traditionally associated with CD4+ Th17 cells. However, IL-17 is also expressed during innate responses to facilitate rapid pathogen clearance. Innate IL-17-expressing cells include various lymphocyte-type subsets, including ILC3, NKT, γδ-T and "natural" Th17 (nTh17) cells. Some reports suggest that neutrophils can express IL-17 during fungal infections. Here, we asked whether neutrophils serve as a source of IL-17 during acute oropharyngeal candidiasis (OPC) using an IL-17A fate-tracking reporter mouse. Mice were subjected to OPC for two days, and oral tissue was analyzed by flow cytometry. IL-17A was expressed by γδ-T cells and TCRβ+ natural Th17 (nTh17) cells, as recently reported. Although infiltrating neutrophils were recruited to the tongue following infection, they did not express the IL-17A reporter. Moreover, neutrophil-depleted mice exhibited normal transcription of both Il17a and downstream IL-17-dependent gene targets after Candida challenge. Thus, in acute OPC, neutrophils are not a measurable source of IL-17 production, nor are they necessary to trigger IL-17-dependent gene expression, although they are essential for ultimate pathogen control.

Oropharyngeal candidiasis (OPC) is an opportunistic fungal infection caused by Candida albicans. OPC is frequent in HIV/AIDS, implicating adaptive immunity. Mice are naive to Candida, yet IL-17 is induced within 24 h of infection, and susceptibility is strongly dependent on IL-17R signaling. We sought to identify the source of IL-17 during the early innate response to candidiasis. We show that innate responses to Candida require an intact TCR, as SCID, IL-7Rα(-/-), and Rag1(-/-) mice were susceptible to OPC, and blockade of TCR signaling by cyclosporine induced susceptibility. Using fate-tracking IL-17 reporter mice, we found that IL-17 is produced within 1-2 d by tongue-resident populations of γδ T cells and CD3(+)CD4(+)CD44(hi)TCRβ(+)CCR6(+) natural Th17 (nTh17) cells, but not by TCR-deficient innate lymphoid cells (ILCs) or NK cells. These cells function redundantly, as TCR-β(-/-) and TCR-δ(-/-) mice were both resistant to OPC. Whereas γδ T cells were previously shown to produce IL-17 during dermal candidiasis and are known to mediate host defense at mucosal surfaces, nTh17 cells are poorly understood. The oral nTh17 population expanded rapidly after OPC, exhibited high TCR-β clonal diversity, and was absent in Rag1(-/-), IL-7Rα(-/-), and germ-free mice. These findings indicate that nTh17 and γδ T cells, but not ILCs, are key mucosal sentinels that control oral pathogens., (© 2014 Conti et al.)

In recent years, proinflammatory cytokines in the nephritic kidney appear to contribute to the pathogenesis of AGN. The complex inflammatory cytokine network that drives renal pathology is poorly understood. IL-17, the signature cytokine of Th17 cells, which promotes autoimmune pathology in a variety of settings, is beginning to be identified in acute and chronic kidney diseases as well. However, the role of IL-17-mediated renal damage in the nephritic kidney has not been elucidated. Here, with the use of a murine model of experimental AGN, we showed that IL-17RA signaling is critical for the development of renal pathology. Despite normal systemic autoantibody response and glomerular immune-complex deposition, IL-17RA(-/-) mice exhibit a diminished influx of inflammatory cells and kidney-specific expression of IL-17 target genes correlating with disease resistance in AGN. IL-17 enhanced the production of proinflammatory cytokines and chemokines from tECs. Finally, we were able to show that neutralization of IL-17A ameliorated renal pathology in WT mice following AGN. These results clearly demonstrated that IL-17RA signaling significantly contributes to renal tissue injury in experimental AGN and suggest that blocking IL-17RA may be a promising therapeutic strategy for the treatment of proliferative and crescentic glomerulonephritis., (© 2014 Society for Leukocyte Biology.)

Multiple forms of candidiasis are clinically important in humans. Established murine models of disseminated, oropharyngeal, vaginal, and cutaneous candidiasis caused by Candida albicans are described in this unit. Detailed materials and methods for C. albicans growth and detection are also described., (Copyright © 2014 John Wiley & Sons, Inc.)

Oropharyngeal candidiasis (OPC [thrush]) is an opportunistic infection caused by the commensal fungus Candida albicans. OPC is common in individuals with HIV/AIDS, infants, patients on chemotherapy, and individuals with congenital immune defects. Immunity to OPC is strongly dependent on the interleukin-23 (IL-23)/IL-17R axis, as mice and humans with defects in IL-17R signaling (IL17F, ACT1, IL-17RA) or in genes that direct Th17 differentiation (STAT3, STAT1, CARD9) are prone to mucocutaneous candidiasis. Conventional Th17 cells are induced in response to C. albicans infection via signals from C-type lectin receptors, which signal through the adaptor CARD9, leading to production of Th17-inducing cytokines such as IL-6, IL-1β, and IL-23. Recent data indicate that IL-17 can also be made by numerous innate cell subsets. These innate "type 17" cells resemble conventional Th17 cells, but they can be activated without need for prior antigen exposure. Because C. albicans is not a commensal organism in rodents and mice are thus naive to this fungus, we had the opportunity to assess the role of CARD9 in innate versus adaptive responses using an OPC infection model. As expected, CARD9(-/-) mice failed to mount an adaptive Th17 response following oral Candida infection. Surprisingly, however, CARD9(-/-) mice had preserved innate IL-17-dependent responses to Candida and were almost fully resistant to OPC. Thus, CARD9 is important primarily for adaptive immunity to C. albicans, whereas alternate recognition systems appear to be needed for effective innate responses.

Oropharyngeal candidiasis (OPC), caused by the commensal fungus Candida albicans, is an opportunistic infection associated with infancy, AIDS, and IL-17-related primary immunodeficiencies. The Th17-associated cytokines IL-23 and IL-17 are crucial for immunity to OPC, but the mechanisms by which they mediate immunity are poorly defined. IL-17RA-deficient humans and mice are strongly susceptible to OPC, with reduced levels of CXC chemokines and concomitantly impaired neutrophil recruitment to the oral mucosa. Paradoxically, humans with isolated neutropenia are typically not susceptible to candidiasis. To determine whether immunity to OPC is mediated via neutrophil recruitment, mice lacking CXCR2 were subjected to OPC and were found to be highly susceptible, although there was no dissemination of fungi to peripheral organs. To assess whether the entire neutrophil response is IL-17 dependent, IL-17RA(-/-) and IL-23(-/-) mice were administered neutrophil-depleting Abs and subjected to OPC. These mice displayed increased oral fungal burdens compared with IL-17RA(-/-) or IL-23(-/-) mice alone, indicating that additional IL-17-independent signals contribute to the neutrophil response. WT mice treated with anti-Gr-1 Abs exhibited a robust infiltrate of CD11b(+)Ly-6G(low)F4/80(-) cells to the oral mucosa but were nonetheless highly susceptible to OPC, indicating that this monocytic influx is insufficient for host defense. Surprisingly, Ly-6G Ab treatment did not induce the same strong susceptibility to OPC in WT mice. Thus, CXCR2(+) and Gr-1(+) neutrophils play a vital role in host defense against OPC. Moreover, defects in the IL-23/17 axis cause a potent but incomplete deficiency in the neutrophil response to oral candidiasis.

Oropharyngeal candidiasis (OPC) is an opportunistic infection caused by Candida albicans. Despite its prevalence, little is known about C. albicans-specific immunity in the oral mucosa. Vaccines against Candida generate both T helper type 1 (Th1) and Th17 responses, and considerable evidence implicates interleukin (IL)-17 in immunity to OPC. However, IL-17 is also produced by innate immune cells that are remarkably similar to Th17 cells, expressing the same markers and localizing to similar mucosal sites. To date, the relative contribution(s) of Th1, Th17, and innate IL-17-producing cells in OPC have not been clearly defined. Here, we sought to determine the nature and function of adaptive T-cell responses to OPC, using a new recall infection model. Mice subjected to infection and re-challenge with Candida mounted a robust and stable antigen-specific IL-17 response in CD4+ but not CD8+ T cells. There was little evidence for Th1 or Th1/Th17 responses. The Th17 response promoted accelerated fungal clearance, and Th17 cells could confer protection in Rag1-/- mice upon adoptive transfer. Surprisingly, CD4 deficiency did not cause OPC but was instead associated with compensatory IL-17 production by Tc17 and CD3+CD4-CD8- cells. Therefore, classic CD4+Th17 cells protect from OPC but can be compensated by other IL-17-producing cells in CD4-deficient hosts.

IL-17 and related cytokines are direct and indirect targets of selective immunosuppressive agents for the treatment of autoimmune diseases and other diseases of pathologic inflammation. Insights into the potential adverse effects of IL-17 blockade can be drawn from the experience of patients with deficiencies in the IL-17 pathway. A unifying theme of susceptibility to mucocutaneous candidiasis is seen in both mice and humans with a variety of genetic defects that converge on this pathway. Mucocutaneous candidiasis is a superficial infection of mucosal, nail or skin surfaces usually caused by the fungal pathogen Candida albicans. The morbidity of the disease includes significant pain, weight loss and secondary complications, including carcinoma and aneurysms. This review describes the known human diseases associated with chronic mucocutaneous candidiasis (CMC) as well as the known and proposed connections to IL-17 signaling. The human diseases include defects in IL-17 signaling due to autoantibodies (AIRE deficiency), receptor mutations (IL-17 receptor mutations) or mutations in the cytokine genes (IL17F and IL17A). Hyper-IgE syndrome is characterized by elevated serum IgE, dermatitis and recurrent infections, including CMC due to impaired generation of IL-17-producing Th17 cells. Mutations in STAT1, IL12B and IL12RB1 result in CMC secondary to decreased IL-17 production through different mechanisms. Dectin-1 defects and CARD9 defects result in susceptibility to C. albicans because of impaired host recognition of the pathogen and subsequent impaired generation of IL-17-producing T cells. Thus, recent discoveries of genetic predisposition to CMC have driven the recognition of the role of IL-17 in protection from mucosal fungal infection and should guide counseling and management of patients treated with pharmacologic IL-17 blockade.

Objective: The goal was to determine the performance of low-risk criteria for serious bacterial illnesses (SBIs) in febrile infants in prospective studies in which empiric antibiotic treatment was withheld, compared with studies (prospective and retrospective) in which empiric antibiotic treatment was administered., Methods: A search of the English-language literature was undertaken by using a PubMed database and reference lists of relevant studies of fever, low-risk criteria, and SBIs. Studies of infants >90 days of age, infants with specific infections, or infants with additional risk factors for infection were excluded. Publications were categorized as retrospective, prospective with empiric antibiotic treatment for all patients, or prospective with antibiotics withheld. The relative risk of SBI in high-risk versus low-risk patients was determined for pooled data in each category. The rates of SBIs in low-risk patients in each category were compared., Results: Twenty-one studies met the inclusion criteria. In prospective studies in which patients were cared for without empiric antibiotic treatment, 6 patients assigned to the low-risk category had SBIs; all recovered uneventfully. The rate of SBIs in these low-risk patients was 0.67%. The relative risk of SBIs in high-risk versus low-risk patients in these studies was 30.56 (95% confidence interval: 7.0-68.13). The rate of SBIs in low-risk patients in all studies was 2.23%. The rate of SBIs in low-risk patients in the prospective studies without empiric antibiotic treatment was significantly different from the rate in all other studies (0.67% vs 2.71%; P = .01)., Conclusions: Low-risk criteria perform well in prospective studies in which empiric antibiotic treatment is withheld. These criteria allow approximately 30% of young febrile infants to be observed without antibiotic treatment, thus avoiding unnecessary hospitalization, nosocomial infection, injudicious use of antibiotics, and adverse effects of antibiotics.

The capsaicin receptor VR1 is a polymodal nociceptor activated by multiple stimuli. It has been reported that protein kinase C plays a role in the sensitization of VR1. Protein kinase D/PKCmu is a member of the protein kinase D serine/threonine kinase family that exhibits structural, enzymological, and regulatory features distinct from those of the PKCs, with which they are related. As part of our effort to optimize conditions for evaluating VR1 pharmacology, we found that treatment of Chinese hamster ovary (CHO) cells heterologously expressing rat VR1 (CHO/rVR1) with butyrate enhanced rVR1 expression and activity. The expression of PKCmu and PKCbeta1, but not of other PKC isoforms, was also enhanced by butyrate treatment, suggesting the possibility that these two isoforms might contribute to the enhanced activity of rVR1. In support of this hypothesis, we found the following. 1) Overexpression of PKCmu enhanced the response of rVR1 to capsaicin and low pH, and expression of a dominant negative variant of PKCmu reduced the response of rVR1. 2) Reduction of endogenous PKCmu using antisense oligonucleotides decreased the response of exogenous rVR1 expressed in CHO cells as well as of endogenous rVR1 in dorsal root ganglion neurons. 3) PKCmu localized to the plasma membrane when overexpressed in CHO/rVR1 cells. 4) PKCmu directly bound to rVR1 expressed in CHO cells as well as to endogenous rVR1 in dorsal root ganglia or to an N-terminal fragment of rVR1, indicating a direct interaction between PKCmu and rVR1. 5) PKCmu directly phosphorylated rVR1 or a longer N-terminal fragment (amino acids 1-118) of rVR1 but not a shorter one (amino acids 1-99). 6) Mutation of S116A in rVR1 blocked both the phosphorylation of rVR1 by PKCmu and the enhancement by PKCmu of the rVR1 response to capsaicin. We conclude that PKCmu functions as a direct modulator of rVR1.