Murine natural killer cell licensing and regulation by T regulatory cells in viral responses.

Natural killer (NK) cells show differential functionality based on their capability of binding to self-MHC consistent with licensing. Here we show in vivo confirmation of the physiologic effects of licensing with differential effects of NK subsets on anti-murine cytomegalovirus (anti-MCMV) responses after syngeneic hematopoietic stem cell transplantation (HSCT) or regulatory T-cell (Treg) depletion. After HSCT, depletion of licensed NK cells led to far greater viral loads in target organs early after infection compared with nondepleted and unlicensed depleted mice. There was a preferential expansion of licensed, C-type lectin-like activating receptor Ly49H+ NK cells with increased IFNγ production after infection in nondepleted mice post-HSCT and after Treg depletion. Adoptive transfer of licensed NK subsets into immunodeficient hosts provided significantly greater MCMV resistance compared with transfer of total NK populations or unlicensed subsets. In non-HSCT mice, only concurrent depletion of Tregs or TGF-ß neutralization resulted in detection of NK licensing effects. This suggests that licensed NK cells are the initial and rapidly responding population of NK cells to MCMV infection, but are highly regulated by Tregs and TGF-ß.

Murine NK-cell licensing is reflective of donor MHC-I following allogeneic hematopoietic stem cell transplantation in murine cytomegalovirus responses.

Natural killer (NK) cells express inhibitory receptors with varied binding affinities to specific major histocompatibility complex class I (MHC-I) haplotypes. NK cells can be classified as licensed or unlicensed based on their ability or inability to bind MHC-I, respectively. The role of donor vs host MHC on their development after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is not known. Following reciprocal MHC-disparate allogeneic transplants and during de novo NK-cell recovery, depletion of the licensed and not unlicensed population of NK cells as determined by the licensing patterns of donor MHC-I haplotypes, resulted in significantly increased susceptibility to murine cytomegalovirus (MCMV) infection. A corresponding expansion of the licensed Ly49H(+) NK cells occurred with greater interferon γ production by these cells than unlicensed NK cells in the context of donor MHC-I. Thus, NK licensing behavior to MCMV corresponds to the donor, and not recipient, MHC haplotype after allo-HSCT in mice.

Contrasting effects of anti-Ly49A due to MHC class I cis binding on NK cell-mediated allogeneic bone marrow cell resistance.

NK subsets have activating and inhibitory receptors that bind MHC-I. Ly49A is a mouse inhibitory receptor that binds with high affinity to H2(d) in both a cis- and trans-manner. Ly49A cis-associations limit trans-interactions with H2(d)-expressing targets as well as mAb binding. We demonstrate that cis-interactions affect mAb effector functions. In vivo administration of anti-Ly49A depleted NK cells in H2(b) but not H2(d) mice. Despite lack of depletion, in vivo treatment with anti-Ly49A reduced NK killing capabilities and inhibited activation, partially due to its agonistic effect. These data explain the previously described in vivo effects on bone marrow allograft rejection observed with anti-Ly49A treatment in H2(d)-haplotype mice. However, prior treatment of mice with poly(I:C) or mouse CMV infection resulted in increased Ly49A expression and Ly49A(+) NK cell depletion in H2(d) mice. These data indicate that, although Ly49 mAbs can exert similar in vivo effects in mice with different MHC haplotypes, these effects are mediated via different mechanisms of action correlating with Ly49A expression levels and can be altered within the same strain contingent on stimuli. This illustrates the marked diversity of mAb effector functions due to the regulation of the level of expression of target Ags and responses by stimulatory incidents such as infection.

The office of student wellness: innovating to improve student mental health.

OBJECTIVE: Despite increasing mental health needs among medical students, few models for effective preventive student wellness programs exist. METHODS: This paper describes a novel approach developed at the University of California (UC) Davis School of Medicine: the Office of Student Wellness (OSW). RESULTS: Improved access and mental health service utilization have been documented, with over half of all students receiving support and clinical care. UC Davis student satisfaction mean scores on the Association of American Medical Colleges Graduation Questionnaire wellness questions have reached or exceeded national average over the last 4 years, since the OSW was founded. CONCLUSIONS: This program may serve as a blueprint for other medical schools in developing effective student wellness programs.

Why Are There So Few Women Medical School Deans? Debunking the Myth That Shorter Tenures Drive Disparities.

PURPOSE: Gender disparities among the senior echelons of academic medicine are striking and persistent. The role of medical school dean has been particularly immune to gender diversity, and limited prior research identified women's shorter decanal tenures as a potential driver. The authors assessed gender differences in tenure length of deanships in the current era to elucidate this finding. METHOD: From October 2020 to June 2021, the authors collected information about medical school deanships that were held from January 1, 2006, to June 30, 2020. All schools were members of the Association of American Medical Colleges (AAMC). The authors collected data from online public records and augmented their findings via direct outreach to medical schools. They used time-to-event analyses before and after adjustment for interim vs permanent status of the initial appointment, school ownership (public/private), and school size to assess for gender differences in length of deanship tenure during the study period. The unit of analysis was deanships, and the primary outcome was length of deanships measured in years. RESULTS: Authors included data on 528 deanships. Women held 91 (17%) of these terms. Men held the majority of permanent deanships (n = 352 [85%]). A greater percentage of the deanships held by women were interim only (n = 27 [30%]) compared with men (n = 85 [20%]). In unadjusted and adjusted analyses, there were no significant gender differences in length of deanship tenures. CONCLUSIONS: Analysis of appointments of AAMC-member medical school deans from 2006 to 2020 revealed that women have remained in their deanships as long as their male counterparts. The myth about women deans' shorter longevity should no longer be promulgated. Academic medicine should consider novel solutions to addressing women's persistent underrepresentation in the dean role, including employing the gender proportionality principle used in the business and legal communities.

Interleukin-10 repletion suppresses pro-inflammatory cytokines and decreases liver pathology without altering viral replication in murine cytomegalovirus (MCMV)-infected IL-10 knockout mice.

OBJECTIVE AND DESIGN: To determine the role of interleukin-10 (IL-10) in protecting against the deleterious pro-inflammatory cytokine response to murine cytomegalovirus (MCMV), we studied the impact of IL-10 repletion in MCMV-infected IL-10 knockout (KO) mice. MATERIALS AND METHODS: IL-10 KO mice were infected with a sub-lethal dose of MCMV and treated daily with 5 µg of mouse recombinant IL-10 (mrIL-10). Cytokine transcription, viral load, cytokine expression and liver histopathology were assessed in IL-10 treated and untreated mice. RESULTS: mrIL-10 repletion suppressed the exaggerated pro-inflammatory cytokine response observed in IL-10 KO mice (vs. control) both systemically and at the organ level, without affecting viral load. Levels of IFN-γ and TNF-α mRNA in livers of treated mice were ~50-70-fold lower than in untreated mice at day 5 post-infection (p ≤ 0.05). In spleens and sera, levels of IFN-γ and IL-6 were significantly lower in treated mice than in untreated mice at day 5-7 post-infection (p ≤ 0.05). IL-10 blunting of cytokine responses was accompanied by attenuation of inflammation in livers of treated mice. CONCLUSIONS: Repletion of IL-10 modulates the exaggerated pro-inflammatory cytokine responses that characterize IL-10 KO mice and protects against liver damage without altering viral load. IL-10 may be useful to control dysregulated pro-inflammatory cytokines responses during CMV infection.

Licensing delineates helper and effector NK cell subsets during viral infection.

Natural killer (NK) cells can be divided into phenotypic subsets based on expression of receptors that bind self-MHC-I molecules, a concept termed licensing or education. Here we show NK cell subsets with different migratory, effector, and immunoregulatory functions in dendritic cell and antigen (ag)-specific CD8+ T cell responses during influenza and murine cytomegalovirus infections. Shortly after infection, unlicensed NK cells localized in draining lymph nodes and produced GM-CSF, which correlated with the expansion and activation of dendritic cells, and resulted in greater and sustained ag-specific T cell responses. In contrast, licensed NK cells preferentially migrated to infected tissues and produced IFN-γ. Importantly, human NK cell subsets exhibited similar phenotypic characteristics. Collectively, our studies demonstrate a critical demarcation between the functions of licensed and unlicensed NK cell subsets, with the former functioning as the classical effector subset and the latter as the stimulator of adaptive immunity helping to prime immune responses.

Use of quantitative real-time PCR (qRT-PCR) to measure cytokine transcription and viral load in murine cytomegalovirus infection.

A quantitative real-time PCR (qRT-PCR) assay was developed to measure cytokine transcription profiles and viral load during sub-clinical and clinical infection with murine cytomegalovirus (MCMV). Primers/fluorogenic probes specific for mouse cytokines and for the immediate early gene 1 (IE1) of MCMV were used to quantitate cytokine responses and viral load in various organs of MCMV infected mice. Increased mRNA levels of TNF-alpha, INF-gamma and IL-10 were detected in the spleens, lungs and livers of clinically infected mice at 5 days post-infection. Transcription of these cytokines was 2-5-fold lower (p=0.07 for each cytokine) in the spleens and 10-100-fold lower in the lungs (p=0.03 for INFgamma, not significant for IL-10 and TNFalpha) and livers (p<0.05 for each cytokine) of sub-clinically infected mice. Clinical MCMV infection induced high levels of IL-6 in the lungs and spleens of infected animals, while no significant transcription of IL-6 was detected in any organ during sub-clinical infection (p<0.05). The timing of peak amounts of INF-gamma, IL-10 and IL-6 observed in the spleens of clinically infected mice correlated with high viral loads in these organs. Cytokine expression rose in the salivary glands later, at day 15, corresponding to the increase in salivary gland viral load. The qRT-PCR demonstrates that infection with MCMV induces an organ-specific cytokine response characterized by the production of TNF-alpha, INF-gamma, IL-6 and IL-10 which correlates with severity of the disease (sub-clinical versus clinical) and with viral load. In summary, qRT-PCR is a sensitive and accurate method to study MCMV infection and host responses to the virus.

A murine model of dual infection with cytomegalovirus and Pneumocystis carinii: effects of virus-induced immunomodulation on disease progression.

Despite the use of antimicrobial prophylaxis, cytomegalovirus (CMV) and Pneumocystis carinii (PC) pneumonia (PCP) are both leading causes of morbidity and mortality in immunocompromised patients. It has previously been reported that CMV infection modulates host immune responses with a variety of mechanisms which include the suppression of helper T cell functions and antigen presenting cell (APC) functions, both of which are critical for PCP resolution. However, the mechanisms of these interactions and other possible immune regulatory effects are not clearly understood. In this study, we investigated the impact of murine CMV (MCMV) induced immunomodulation on the progression of PCP in a co-infection model. Initial results show that dually infected mice had evidence of more severe PC disease, which include a greater loss of body weight, an excess lung PC burden and delayed clearance of PC from lungs, compared to mice with PC infection alone. At day 7 post-infection, dually infected mice had reduced numbers of MHC-II expressing cells in the lung interstitium and lymph nodes and reduced migration of CD11c+ cells to both the tracheobronchial lymph nodes and alveolar spaces. Dual infected mice showed elevated numbers of specific CD8 responses concomitant with a decrease in activated CD4+ T cells in both the lymph nodes and in alveolar spaces when compared to mice infected with MCMV alone. These data suggest that MCMV infection inhibits the immune responses generated against PC which contribute to the delayed clearance of the organism.

Results of an antimicrobial control program at a university hospital.

PURPOSE: The results of the first five years of an ongoing antimicrobial control program are reported. METHODS: In 1998, a multidisciplinary antimicrobial subcommittee of the pharmacy and therapeutics committee of a university hospital was formed and charged with making formulary interventions in an effort to reduce rising antimicrobial resistance rates and drug expenditures. In 1999, a number of measures were implemented for controlling antimicrobial use. Selected antimicrobials with the potential for inappropriate use or whose inappropriate use had been documented were placed in the control of physicians in the infectious diseases (ID) division. Prior approval by an ID physician was required before the pharmacy could dispense these agents. Other key interventions included removal of ceftazidime and cefotaxime from the formulary, restriction of vancomycin and carbapenem use, and replacement of ciprofloxacin with levofloxacin as the sole fluoroquinolone on the formulary. Data regarding antimicrobial use and expenditures between 1998 and 2002 were compared and analyzed. RESULTS: Antimicrobial use was reduced by 80% for third-generation cephalosporins and 15% for vancomycin following the implementation of the new antimicrobial policies. Antimicrobial-resistance patterns for many important gram-negative pathogens, including Pseudomonas aeruginosa, demonstrated a reversal of previous increases. In addition, the rate of methicillin-resistant Staphylococcus aureus decreased by an average of 3% each year from 1999 to 2002. Pharmacy expenditures for all antimicrobials, including antiviral, antifungal, and antibacterial agents, decreased 24.7%, with a cumulative cost saving of 1,401,126 US dollars, without inflation assumptions. CONCLUSION: The implementation of an antimicrobial control program decreased the use of selected antimicrobial agents and resulted in substantial reduction of expenditures for antimicrobials.

Sex differences in adverse reactions to antiretroviral drugs.

There have been recent increases in the number of female participants in HIV clinical trials and the number of studies addressing the influence of sex on HIV infection. The findings of some studies indicate a potential sex differences in the frequency and severity of adverse reactions to antiretroviral drugs. This article reviews the available data on the incidence and characteristics of potential sex differences in adverse reactions to certain nucleoside and nonnucleoside reverse transcriptase inhibitors and protease inhibitors. Adverse effects for which a sex difference has been reported include lactic acidosis, rash, elevation in liver enzymes, dyslipidemia, and insulin resistance. The reasons for these sex differences in adverse drug events are unclear but may include differences between men and women in body mass index and fat composition, hormonal effects on drug metabolism, or the effects of genomic constitutional differences on the levels of various enzymes. These differences warrant further study.

Use of club drugs by HIV-seropositive and HIV-seronegative gay and bisexual men.

Club drugs such as methylenedioxymethamphetamine (MDMA, ecstasy), gamma hydroxybutyrate (GHB), and ketamine are among the fastest-growing drugs of abuse in the United States. Reports have shown that some gay and bisexual men are likely to engage in club-drug use in a myriad of venues. This is concerning given that the use of club drugs has been linked to high-risk sexual behaviors. Further, the use of club drugs by HIV-seropositive individuals may have detrimental outcomes on disease progression by either influencing adherence, resulting in drug-drug interactions with antiretrovirals, or potentially compounding immune suppression. Clinicians caring for HIV-seropositive and -seronegative individuals should be aware of the clinical effects and management guidelines associated with these chemicals. This article reviews the available literature with regard to the use of club drugs by HIV-seropositive and -seronegative gay and bisexual men. Although club-drug use may be associated with many risk behaviors for HIV infection, this review focuses on risk behavior among gay and bisexual men since this is the group for which the most data have been reported. The clinical effects and management guidelines associated with these agents are described, and the potential detrimental effects of these substances on HIV disease are discussed.

Concurrent use of antiretrovirals and anticonvulsants in human immunodeficiency virus (HIV) seropositive patients.

Seizure disorders may complicate HIV disease, either as a direct result of HIV or as a manifestation of a secondary opportunistic infection. Unless a reversible cause of seizure activity can be discerned, current treatment guidelines recommend the use of anticonvulsant drugs in these patients. The concurrent use of antiretrovirals and anticonvulsants is a poorly studied area. Controlled clinical trials examining drug-drug and drug-disease interactions in this area are scant, leaving clinicians a therapeutic dilemma in terms of drug selection. Most studies have been retrospective in nature. Generalized seizures appear to be most common and occur most frequently in patients with more severe disease as indicated by lower mean CD4(+) cell counts. In short follow-up periods, seizures appear to recur relatively frequently. Treatment of seizures in this population is hindered by a lack of clear data and numerous reports of drug-drug and drug-disease interactions. In order to best provide evidence-based care, controlled clinical trials are needed to discern which anticonvulsants are best suited for use in this population. Trials should also examine appropriate dose adjustments that may be warranted when anticonvulsants and antiretrovirals agents are used concurrently. Unless an identifiable and reversible cause of seizures is identified in this patient population seizures should be treated with standard therapy and close follow-up and monitoring. Newer anticonvulsants (i.e., gabapentin, tiagabine) with fewer drug interactions may be better alternatives when compared to older anticonvulsant agents. Clinicians might avoid valproic acid given some conflicting reports regarding potential for increasing viral replication.

Poppers: epidemiology and clinical management of inhaled nitrite abuse.

Commonly referred to as "poppers," inhaled nitrites have a long history of abuse. Poppers are rapid-onset, short-acting potent vasodilators that produce a rush characterized by warm sensations and feelings of dizziness. Poppers sometimes are used to facilitate anal intercourse because of their actions on the anal sphincter. Epidemiologically, the frequent use of nitrites by men who have sex with men has led some experts to implicate these chemicals in the pathogenesis of Kaposi's sarcoma and acquired immunodeficiency syndrome. Controlled clinical trials to examine this potential correlation have not been conducted, and the use of nitrites simply may be a marker for other high-risk behaviors such as unprotected sex. Although regulated in the United States, many nitrite compounds and isomers are sold at various venues including bars, bookstores, and over the Internet. Adverse effects associated with these products vary from mild allergic reactions to life-threatening methemoglobinemia. The potential for drug-drug interactions and a propensity toward unsafe sex also exist. Clinicians should be familiar with the populations most likely to abuse these agents and with the clinical effects and management guidelines for acute ingestions.