Mannose receptor (MR) and Toll-like receptor 2 (TLR2) influence phagosome maturation during Leishmania infection

Leishmania enter macrophages through receptor-mediated phagocytosis and survive the harsh environment of a phagolysosome. Here, we investigated the interaction between mannose receptor (MR), Toll-like receptor 2 (TLR2), and Leishmania, and the subsequent impact on phagosome maturation. Leishmania parasites are able to delay phagosome maturation, not reaching full maturation until 5 hours post-engulfment. Here, maturation of Leishmania major- and Leishmania donovani-containing phagosomes proceeded as expected in the WT macrophages becoming LAMP1 positive by 6 hours. Interestingly, MR-/- macrophages become LAMP1 positive by ~2 hours and ~4 hours post-infection Leishmania-containing phagosomes lost LAMP1 expression and gained the early marker EEA1. LAMP1 expression was again observed by 6 hours. Leishmania LPG was essential for the delay in both WT and MR-/- macrophages but was not essential for the early maturation (2 hours) observed in MR-/- macrophages. Serum opsonization of Leishmania prior to infection induced identical phagosome maturation patterns in WT and MR-/- macrophages. In the absence of MyD88 or TLR2 on macrophages, Leishmania phagosomes matured significantly faster, becoming LAMP1 positive by ~1-2 hours. These studies add to the knowledge that phagosome maturation is influenced by multiple receptor-ligand interactions and signalling pathways.

Correlation of quantitative total HER2 expression and HER2 homodimers with histopathologic characteristics of breast cancers in the FinHer study

11061

Background: We recently reported that the HERmark assay (Monogram Biosciences) accurately measures continua of total HER2 expression (H2T) and HER2 homodimers (H2D) over a wide (∼3 logs) dynamic range, and that a higher concordance was observed between H2T and HER2 status with more stringent central tests as compared with IHC tests performed locally (Joensuu et al, 2008 SABCS,abstract 2071). H2D/H2T ratio was reported as a marker of activated HER2 and a prognosticator of disease progression in HER2+ patients not treated with trastuzumab in the adjuvant setting (Bates et al, 2008 SABCS,abstract 1074). In this follow-up analysis, H2T, H2D, and H2D/H2T ratio were correlated with histopathologic characteristics of breast cancers in the FinHer study. Methods: The HERmark assay was used to measure H2T and H2D in 899 formalin-fixed, paraffin-embedded FinHer specimens. The results were correlated with histopathologic characteristics of breast cancers in the FinHer study (Joensuu et al, N Engl J Med2006;354), including estrogen receptor/progesterone receptor (ER/PR), tumor grade, tumor size, lymph node metastasis, and stage. Results: Higher H2T and H2D levels correlated with ER/PR negativity and high tumor grade (P<0.0001). 42% (102/244) of ER- and 37% (137/374) of PR- cases were HERmark Positive; while 17% (110/655) of ER+ and 14% (75/524) of PR+ cases were HERmark Positive. 10% (13/136) of grade 1, 18% (65/353) of grade 2, and 35% (131/375) of grade 3 tumors were HERmark Positive. No significant association was found between H2T or H2D and tumor size, lymph node metastasis or stage. ER/PR negative and poorly differentiated cancers had higher H2D/H2T ratios (P=0.013), and H2D/H2T ratios >0.6 were associated with smaller primary tumor diameters at the time of cancer detection (P=0.009). Conclusions: The quantitative H2T measurement confirms the known correlations between HER2 expression and histopathologic characteristics of breast cancer. The novel H2D measurement and H2D/H2T ratio may provide further insights into HER2 activation and better diagnostic tests for targeted HER2 therapy.

[Table: see text]

Quantitative measurements of HER2 expression and HER2 homodimer using a novel proximity based assay: comparison with HER2 status by immunohistochemistry and chromogenic in situ hybridization in the FinHer study

Abstract #2071

Background: The accuracy and reliability of current methods, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), to assess HER2 status has recently been a subject of debate. The best method to assess HER2 status remains controversial. We developed a novel assay (HERmark, Monogram Biosciences) that provides precise quantification of HER2 expression (H2T) and HER2 homodimer (H2D) in formalin-fixed paraffin-embedded (FFPE) tissues. We compared H2T and H2D to local IHC, central chromogenic in situ hybridization (CISH) and central IHC retesting of breast cancers from the FinHer study.&#x2028; Methods: H2T and H2D were detected through light-dependent release of fluorescent tags (VeraTag reporters) conjugated to a HER2 antibody, requiring proximity to a second HER2 “scissors” antibody. The VeraTag signal was quantified by capillary electrophoresis and normalized to tumor area. Assay comparisons correlated H2T and H2D with HER2 testing by local IHC and central CISH from FinHer (Joensuu et al, N Engl J Med 2006;354), as well as central HER2 status reassessment by combination of externally performed central IHC retesting (PhenoPath labs, Seattle, WA) and central CISH (FinHer) according to ASCO/CAP guideline for HER2 testing in breast cancer (Wolff et al, Arch Pathol Lab Med 2007;131).&#x2028; Results: H2T and H2D in 899 evaluable FinHer samples described a continuum over a wide dynamic range (∼ 3 logs), in contrast with conventional IHC categories (0-3+). The correlation between H2T and IHC categories was significant (P &lt; .0001). Overlap of H2T among the IHC categories was observed. H2D showed a similar correlation with IHC and a general correlation with H2T (P &lt; .0001). A H2T cutoff value, based on its ability to distinguish high and low responders in a cohort of metastatic breast cancer patients treated with trastuzumab-based regimens (log10 H2T= 1.14, Leitzel et al, 2008 ASCO, abstract 1002), was used to define HERmark negative (-) and positive (+), which were then compared with IHC and CISH results. The concordances between HERmark (-) and local IHC (-), central CISH (-), and central HER2 reassessment (-) were 89%, 84%, and 91%, respectively. The concordances between HERmark (+) and local IHC (+), central CISH (+), and central HER2 reassessment (+) were 71%, 89%, and 92%, respectively. The HERmark test showed greater overall concordance with central HER2 reassessment (91%) than with local IHC (84%) and central CISH (87%)&#x2028; Conclusions: HERmark reliably measures H2T and H2D in FFPE tissues. H2T showed excellent concordance with central HER2 status according to ASCO/CAP guideline for HER2 testing. The precise quantification of H2T and H2D may provide novel, quantifiable, predictive tests for targeted HER2 therapy.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2071.

Phenotypic hypersusceptibility to non-nucleoside reverse transcriptase inhibitors in treatment-experienced HIV-infected patients: impact on virological response to efavirenz-based therapy

BACKGROUND

Enhanced susceptibility to non-nucleoside reverse transcriptase inhibitors (NNRTI) was recently described in association with increased resistance to nucleoside analogs (nucleoside reverse transcriptase inhibitors; NRTI).

OBJECTIVES

To determine the prevalence of NNRTI hypersusceptibility, the genotypic correlates, and its impact on virologic response to efavirenz-based salvage therapy.

METHODS

Genotype and phenotype testing was performed retrospectively on baseline isolates from 30 patients who received salvage therapy containing efavirenz. NNRTI hypersusceptibility was defined as a 50% inhibitory concentration (IC(50)) of < 0.5 that of the wild-type control.

RESULTS

Eight isolates had major NNRTI mutations. Among the 22 isolates with no major NNRTI mutations, 11 (50%) were hypersusceptible to efavirenz, 10 (45%) to delavirdine, and eight (36%) to nevirapine. Among eight isolates with NNRTI mutations, NNRTI resistance was present, but at lower than expected levels. The number of NRTI mutations was correlated inversely with the fold decrease in susceptibility to efavirenz (Spearman's rho, -0.57; P = 0.005), delavirdine (rho, -0.43; P = 0.04), and nevirapine (rho, -0.69; P < 0.001). Excluding subjects with NNRTI mutations, subjects with efavirenz hypersusceptibility at baseline had significantly better virologic suppression over 24 weeks than those without efavirenz hypersusceptibility (P < 0.001).

CONCLUSION

NNRTI hypersusceptibility is common in heavily treated but NNRTI naive patients and is related directly to NRTI resistance mutations. Among patients receiving efavirenz-containing regimens, NNRTI hypersusceptibility was associated with an improved virologic outcome after 24 weeks of therapy. A reversal of phenotypic resistance was seen in patients with NNRTI mutations in the presence of multiple NRTI mutations, but no obvious virologic benefit of this phenomenon was seen in this study.

A new pathway to product standardization

As the benefits of product standardization become more evident in improved financial, managerial, and clinical outcomes, tools to make the process easier will be in demand. Once a standardization program is established, e-commerce offers tools to keep it on track.

Interhospital transfers, the COBRA Law (1985), and the use of a public assistance health plan

Public outcry regarding unsafe interhospital patient transfers led to the passage of the COBRA Law of 1985. Since its implementation in 1986, the law has been sharply criticized for its sporadic enforcement, narrow focus, and lack of care provisions for the poor. We reviewed retrospectively the charts of all emergency department patients transferred from two Milwaukee private hospitals during two identical 6-month periods in 1985-1986 and 1988-1989. We compared demographic and clinical characteristics of the patients transferred during the two periods. The emergency departments cared for 15% of Milwaukee's emergency patient population and transferred 216 and 200 patients during each respective period. Uninsured transfers fell from 32% to 17% of the study populations. Although the proportion of the local population belonging to a health maintenance organization (HMO) did not change, transfer of HMO patients increased from 14% to 27%. Transfers to the area's various tertiary care centers made up 21% and 35% of all transfers and were conducted without regard to insurance status. There was a fourfold increase in the use of the county's public assistance plan for emergency hospitalization of indigent patients at local hospitals. Although the number of uninsured patients transferred from the study hospitals decreased markedly, this decrease was counterbalanced by increased private hospital use of the county's emergency hospitalization plan for indigent patients. This successful plan bears further examination by health policy planners as an important model for the provision of emergency hospitalization for the indigent.

Code teams and the review of cardiac arrests

A new system for responding to Codes, or resuscitations of patients with cardiopulmonary arrest, was implemented at St Luke's Medical Center, Milwaukee. A teaching program was begun to establish the Advanced Cardiac Life Support (ACLS) guidelines as the standard of care. A task force defined the composition of the Code team and was then designated the Code Review Committee, meeting monthly to review all Codes. Indicators for review were established. Code review is followed by a letter to the physician Code team leader and/or registered nurse. Data for 18 months, still preliminary, show improved compliance with indicators for documentation and for adherence to ACLS guidelines.

Rapid detection of influenza virus H1 by the polymerase chain reaction

We applied a combination of reverse transcription (RT) with the polymerase chain reaction (PCR) for a rapid detection of influenza virus H1 subtype. We amplified a 441 bp segment of relatively high genetic stability of the hemagglutinin gene. Experimental conditions were established using plasmid DNA and infected cell cultures. The test was applied to 28 nasopharyngeal lavages from patients, two of which were positive for influenza virus H1. When the amplified DNA of a positive sample was sequenced we found 97% homology with the recent strain A/USSR/70.

A new evaluation method for instructors of advanced cardiac life support

This study evaluated the ability of a specific educational program to teach instructors of advanced cardiac life support (ACLS) how to identify errors committed by team leaders of cardiac arrest simulations. The design compared experimental and control groups for differences in identification of critical performance errors, grade assignments and errors specifically emphasized in the educational program. The group receiving the educational program documented more critical performance errors (1.70 vs. 1.10, P = 0.006), made more correct grade assignments (2.35 vs. 2.0, P = 0.026), and identified more errors that were emphasized in the educational program (3.61 vs. 2.25, P = 0.0001) than the control group. The data strongly suggests that the educational program accounted for the observed differences.

Atropine in asystole: human studies

Current research supporting the use of atropine for asystole is limited. Reported in the literature are the cases of 26 patients who presented with a rhythm of asystole. Of these, only eight were clearly in refractory asystole after epinephrine and sodium bicarbonate, only seven were prehospital patients, and only two were delineated as being intubated. Despite such limited data, atropine has been advocated for asystole, and use of the drug is included in the recommendations of the American Heart Association. We undertook a retrospective review of our prehospital experience with refractory asystole for a four-year period from January 1979 to December 1982. All patients with trauma or poisoning and all pediatric arrests were excluded. All patients who received calcium chloride during resuscitation also were excluded. One hundred seventy patients presented in cardiorespiratory arrest with an initial rhythm of asystole. Of these, 84 remained in refractory asystole after receiving epinephrine and sodium bicarbonate. Forty-three patients in this group received atropine. The successful resuscitation rate in the atropine group was 14% (6/43), while in the control group it was 0% (0/41) (P less than .04). A successful resuscitation was defined as conveyance of a patient with a rhythm and a pulse to an emergency department. Patients were compared for age, sex, witnessing of arrest, cardiac history, and cardiac drugs. No other significant differences were noted between groups. No patient who received atropine for refractory asystole was discharged alive.