CD4+ cytolytic effectors are inefficient in the clearance of Listeria monocytogenes

Cytotoxic T lymphocytes (CTL) recognize and lyse target cells through the interaction of the T-cell receptor complex with the class I or class II major histocompatibility complex (MHC). The production of class I-restricted CTL has been shown to be critical to the elimination of specific pathogens including . However, the function of class II-restricted CTL in the clearance of intracellular pathogens is poorly understood. H-2β-microglobulin-deficient mice (βM−/−) are not able to produce CD8 CTL in response to infection with . We used this model to evaluate the efficacy of class II-restricted CTL, in the absence of a class I-restricted response, during a primary infection with . We demonstrate that, despite their effectiveness in adoptive transfer of protection, -specific CD4 class II-restricted cytotoxic lymphocytes are ineffective in decreasing titres of in the spleen after an established infection. In βM−/− mice, persistence of in the spleen was found preferentially in class II-negative cells. Surprisingly, class I-restricted CTL from C57BL/6 mice were capable of decreasing bacterial titres during an established infection even in the absence of detectable class I on the surface of cells from βM−/− mice. These data strongly suggest that, in the absence of a class I-restricted response, pathogens that elicit a class II-restricted cytotoxic response may escape prompt eradication by the immune system

Development and validation of the Patient‐Physician Relationship Scale among patients with irritable bowel syndrome

BackgroundAn effective patient‐physician relationship (PPR) is essential to the care of patients with irritable bowel syndrome (IBS). We sought to develop and validate an IBS‐specific instrument to measure expectations of the PPR.MethodsWe conducted structured focus groups about PPRs with 12 patients with IBS. Qualitative analysis was used to generate a questionnaire (the Patient‐Physician Relationship Scale [PPRS]), which was modified with input from content experts and usability testing. For validation, we administered it online to US adults with IBS. Participants also completed the Functional Bowel Disorder Severity Index, the Rome III Adult Functional gastrointestinal (GI) Disorder Criteria Questionnaire, and modified versions of the Communication Assessment Tool (CAT‐15) and Patient‐Doctor Relationship Questionnaire (PDRQ‐9). We performed principal components factor analysis for the PPRS.Key ResultsThe PPRS contained 32 questions with responses on a 7‐item Likert scale. Themes included interpersonal features, clinical care expectations, and aspects of communication. One thousand and fifty‐four eligible individuals completed the survey (88% completion rate). Most participants were middle aged (mean 48 years, SD 16.3), white (90%), and female (86%). Factor analysis showed only one relevant factor, relating to quality of PPR. The final scale ranged from possible‐96 to +96 (mean 62.0, SD 37.6). It correlated moderately with the CAT‐15 (r=.40, P<.001) and PDRQ‐9 (r=.30, P<.001), establishing concurrent validity.Conclusions & InferencesWe describe the development and validation of the first questionnaire for use in measuring patient expectations of the PPR, which can be used for future outcomes studies and training physicians.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138227/1/nmo13106.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138227/2/nmo13106_am.pd

A simple rule to identify patients with chronic obstructive pulmonary disease who may need treatment reevaluation

BACKGROUND: A simple rule based on short-acting inhaled β2-agonist (SABA) use could identify patients with chronic obstructive pulmonary disease (COPD) at increased risk of exacerbations and signal the need for maintenance therapy change, similar to asthma "Rules of Two(®)". METHODS: Associations between SABA use, COPD exacerbations, and health care costs over 1 year were examined retrospectively using de-identified patient data from the Optum Research Database (ORD; N = 56,581) and the Impact National Benchmark Database (IMPACT™; N = 9423). Nebulized and metered-dose inhaler (MDI) SABA doses were normalized to 2.5 mg and 90 mcg albuterol equivalents, respectively. RESULTS: The GOLD initiative establishes ≥2 exacerbations/year as indicative of increased risk in COPD. We identified a correlation (p < 0.0001) between 1.5 SABA doses/day and this frequency of exacerbations. In ORD, patients using ≥1.5 versus <1.5 SABA doses/day experienced significantly more exacerbations: 1.92 (95% confidence interval [CI], 1.89-1.96) versus 1.36 (95% CI, 1.34-1.38) per patient year (PPY). Above-threshold use was associated with higher average annual COPD-related costs (2010 $US):$21,868 (standard deviation [SD], $53,910) versus$11,686 (SD, $32,707) for nebulized SABA only,$9216 (SD, $30,710) versus$7334 (SD, $24,853) for MDI SABA only, and$15,806 (SD, $35,260) versus$11,233 (SD, $27,006) for both nebulized and MDI SABA. IMPACT™ validated these findings. CONCLUSION: Patients with COPD using ≥1.5 SABA doses/day were at increased risk of exacerbations. Our results suggest a "Rule of 3-2": SABA use ≥3 times in 2 days should be considered a clinical marker for needing treatment reevaluation

Using quantile regression to investigate racial disparities in medication non-adherence

<p>Abstract</p> <p>Background</p> <p>Many studies have investigated racial/ethnic disparities in medication non-adherence in patients with type 2 diabetes using common measures such as medication possession ratio (MPR) or gaps between refills. All these measures including MPR are quasi-continuous and bounded and their distribution is usually skewed. Analysis of such measures using traditional regression methods that model mean changes in the dependent variable may fail to provide a full picture about differential patterns in non-adherence between groups.</p> <p>Methods</p> <p>A retrospective cohort of 11,272 veterans with type 2 diabetes was assembled from Veterans Administration datasets from April 1996 to May 2006. The main outcome measure was MPR with quantile cutoffs Q1-Q4 taking values of 0.4, 0.6, 0.8 and 0.9. Quantile-regression (QReg) was used to model the association between MPR and race/ethnicity after adjusting for covariates. Comparison was made with commonly used ordinary-least-squares (OLS) and generalized linear mixed models (GLMM).</p> <p>Results</p> <p>Quantile-regression showed that Non-Hispanic-Black (NHB) had statistically significantly lower MPR compared to Non-Hispanic-White (NHW) holding all other variables constant across all quantiles with estimates and p-values given as -3.4% (p = 0.11), -5.4% (p = 0.01), -3.1% (p = 0.001), and -2.00% (p = 0.001) for Q1 to Q4, respectively. Other racial/ethnic groups had lower adherence than NHW only in the lowest quantile (Q1) of about -6.3% (p = 0.003). In contrast, OLS and GLMM only showed differences in mean MPR between NHB and NHW while the mean MPR difference between other racial groups and NHW was not significant.</p> <p>Conclusion</p> <p>Quantile regression is recommended for analysis of data that are heterogeneous such that the tails and the central location of the conditional distributions vary differently with the covariates. QReg provides a comprehensive view of the relationships between independent and dependent variables (i.e. not just centrally but also in the tails of the conditional distribution of the dependent variable). Indeed, without performing QReg at different quantiles, an investigator would have no way of assessing whether a difference in these relationships might exist.</p

A Crucial Role for Infected-Cell/Antibody Immune Complexes in the Enhancement of Endogenous Antiviral Immunity by Short Passive Immunotherapy

Antiviral monoclonal antibodies (mAbs) represent promising therapeutics. However, most mAbs-based immunotherapies conducted so far have only considered the blunting of viral propagation and not other possible therapeutic effects independent of virus neutralization, namely the modulation of the endogenous immune response. As induction of long-term antiviral immunity still remains a paramount challenge for treating chronic infections, we have asked here whether neutralizing mAbs can, in addition to blunting viral propagation, exert immunomodulatory effects with protective outcomes. Supporting this idea, we report here that mice infected with the FrCasE murine retrovirus on day 8 after birth die of leukemia within 4–5 months and mount a non-protective immune response, whereas those rapidly subjected to short immunotherapy with a neutralizing mAb survive healthy and mount a long-lasting protective antiviral immunity with strong humoral and cellular immune responses. Interestingly, the administered mAb mediates lysis of infected cells through an antibody-dependent cell cytotoxicity (ADCC) mechanism. In addition, it forms immune complexes (ICs) with infected cells that enhance antiviral CTL responses through FcγR-mediated binding to dendritic cells (DCs). Importantly, the endogenous antiviral antibodies generated in mAb-treated mice also display the same properties, allowing containment of viral propagation and enhancement of memory cellular responses after disappearance of the administered mAb. Thus, our data demonstrate that neutralizing antiviral mAbs can act as immunomodulatory agents capable of stimulating a protective immunity lasting long after the end of the treatment. They also show an important role of infected-cells/antibody complexes in the induction and the maintenance of protective immunity through enhancement of both primary and memory antiviral T-cell responses. They also indicate that targeting infected cells, and not just viruses, by antibodies can be crucial for elicitation of efficient, long-lasting antiviral T-cell responses. This must be considered when designing antiviral mAb-based immunotherapies