A flow microfluorimetric analysis of the binding of immunoglobulins to Fc gamma receptors on brush borders of the neonatal mouse jejunal epithelium.

In order to determine whether the neonatal mouse small intestine has the ability to be selective in the binding of homologous immunoglobulin isotypes, mouse immunoglobulins were tested for their ability to bind to brush borders isolated from jejunal enterocytes of neonatal and adult mice. The binding of immunoglobulins to brush borders was detected by fluorescence-activated cell sorter (FACS) analysis. The results showed that brush borders from 12-day-old mice bound mouse immunoglobulins selectively, binding IgG2a, IgG2b, IgG3 and IgE but not IgG1, IgM or IgA. Similarly, at 16 days, only IgG2a, IgG2b, IgG3 and IgE were bound significantly. The ability of jejunal brush borders to bind gamma-globulins declined with age and their selectivity was lost such that in mice of 18 days and over not one of the immunoglobulins tested was bound. It was concluded that neonatal mouse jejunal Fc gamma receptors bind IgG2a and IgG2b almost exclusively. The sudden drop in binding between 16 and 18 days coincides with the previously reported age at which immunoglobulin transmission across the gut in the neonatal mouse ceases (closure).     

Selection by phage display of llama conventional V(H) fragments with heavy chain antibody V(H)H properties

A llama single domain antibody (dAb) library designed and constructed to contain only heavy chain antibody variable domains (V(H)Hs) also contained a substantial number of typical conventional antibody heavy chain variable sequences (V(H)s). Panning the library against two carbohydrate-specific antibodies yielded anti-idiotypic dAbs and enriched solely for sequences from the V(H) subpopulation of the library. The conventional antibody origin of these V(H)s was confirmed by using oligonucleotide probes, specific for the enriched V(H)s, to identify the parental sequences in the message employed in library construction. Surprisingly, these V(H) dAbs, which are produced in high yield in Escherichia coli, are highly soluble, have excellent temperature stability profiles and do not display any aggregation tendencies. The very close similarity of these molecules to human V(H)s makes them potentially very useful as therapeutic dAbs.     

Latex specific IgE: performance characteristics of the IMMULITE 2000 3gAllergy assay compared with skin testing.

BACKGROUND: In the absence of a US Food and Drug Administration (FDA)-cleared latex skin testing reagent, in vitro tests remain important for the diagnosis of latex allergy. OBJECTIVE: To evaluate the performance characteristics of IMMULITE 2000 3gAllergy (Immulite), a third-generation, FDA-cleared, continuous random-access immunoanalyzer, for the quantification of latex specific IgE. METHODS: Stored serum samples (N = 201) from patients classified as having positive or negative latex puncture skin test results were measured for latex specific IgE levels using Immulite, and these data were compared with historical results from 3 second-generation, FDA-cleared IgE antilatex assays (AlaSTAT [Ala], AutoCAP [CAP], and HY*TEC enzyme immunoassay [HT]). RESULTS: The diagnostic performances of the CAP, Ala, and Immulite assays (> or = 0.35 kU/L cutoff value) were equivalent in sensitivity and specificity (P > .05). The HT assay (> or = 0.05 kU/L cutoff value) was more sensitive and less specific (P < .05). Immulite (> or = 0.10 kU/L cutoff value) had greater sensitivity than Ala and CAP and greater specificity than HT (P < .05 for both). Diagnostic efficiency was greater for Immulite than for CAP, Ala, and HT (P < .05). CONCLUSIONS: The Immulite system is superior in diagnostic performance, especially at the 0.10 kU/L or greater cutoff level, for the diagnosis of latex allergy compared with older, second-generation assays. Immulite still misclassifies 15.5% of puncture skin test-positive individuals as negative for latex specific IgE. Compared with second-generation assays, Immulite represents a technological advance, with enhanced speed and less operator intervention.     

Comparison of a Multiplexed Fluorescent Covalent Microsphere Immunoassay and an Enzyme-Linked Immunosorbent Assay for Measurement of Human Immunoglobulin G Antibodies to Anthrax Toxins

Recently, the Centers for Disease Control and Prevention reported an accurate, sensitive, specific, reproducible, and quantitative enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to Bacillus anthracis protective antigen (PA) in human serum (C. P. Quinn, V. A. Semenova, C. M. Elie et al., Emerg. Infect. Dis. 8:1103-1110, 2002). The ELISA had a minimum detectable concentration (MDC) of 0.06 μg/ml, which, when dilution adjusted, yielded a whole-serum MDC of 3.0 μg of anti-PA IgG per ml. The reliable detection limit (RDL) was 0.09 μg/ml, while the dynamic range was 0.06 to 1.7 μg/ml. The diagnostic sensitivity of the assay was 97.6% and the diagnostic specificity was 94.2% for clinically verified cases of anthrax. A competitive inhibition anti-PA IgG ELISA was also developed to enhance the diagnostic specificity to 100%. We report a newly developed fluorescence covalent microbead immunosorbent assay (FCMIA) for B. anthracis PA which was Luminex xMap technology. The FCMIA MDC was 0.006 μg of anti-PA IgG per ml, the RDL was 0.016 μg/ml, and the whole-serum equivalent MDC was 1.5 μg/ml. The dynamic range was 0.006 to 6.8 μg/ml. Using this system, we analyzed 20 serum samples for anti-PA IgG and compared our results to those measured by ELISA in a double-masked analysis. The two methods had a high positive correlation (r² = 0.852; P < 0.001). The FCMIA appears to have benefits over the ELISA for the measurement of anti-PA IgG, including greater sensitivity and speed, enhanced dynamic range and reagent stability, the use of smaller sample volumes, and the ability to be multiplexed (measurement of more than one analyte simultaneously), as evidenced by the multiplexed measurement in the present report of anti-PA and anti-lethal factor IgG in serum from a confirmed clinical anthrax infection.     

Genomic rearrangements in childhood spinal muscular atrophy: linkage disequilibrium with a null allele.

Autosomal recessive childhood onset spinal muscular atrophy has been mapped to chromosome 5q13. We report the analysis of a polymorphic microsatellite which shows linkage disequilibrium with the disease. The linkage disequilibrium is observed with a null allele which is seen as the non-inheritance of alleles from one or both parents. The inheritance of a null allele was observed in 26 out of 36 (72%) informative childhood onset spinal muscular atrophy (SMA) families tested, of all types of severity and from a variety of ethnic backgrounds. In seven families segregating for the severe Werdnig-Hoffmann or SMA type I, no alleles were inherited from either parent using this microsatellite. This null allele may represent a deletion which is either closely associated with, or causes, the disease.     

A single measurement of CD38CD8 cells in HIV+, long-term surviving injecting drug users distinguishes those who will progress to AIDS from those who will remain stable

This study compares the predictive power of a single measurement of CD8+CD38+, CD8+CD45RO+ or CD8+CD38+CD45RO+ subpopulations in predicting progression to AIDS in a cohort of HIV+ long-term surviving injecting drug users. The results showed that both the total CD8+ percentage, and the CD8+CD38+ and CD8+CD38+CD45RO+ subpopulations of cells all individually predicted progression to AIDS. In combination with CD4, only the CD8+CD38+ subpopulation enhanced the predictive power of the CD4 percentage alone. The CD8+ percentage correlated negatively with the CD4 percentage and the CD8+CD45RO+ subpopulation did not predict disease progression. The proportion of CD8+CD38+ cells identified which patients with a moderate CD4 level were more likely to progress to AIDS, and conversely, which patients with a low CD4 count were likely to remain clinically stable. The results were consistent irrespective of whether time was measured from the date of seroconversion, or from the date of the test. This study is the first to measure these markers in HIV-infected injecting drug users, and in long-term survivors. The results demonstrate the considerable added value of the CD8+CD38+ cell percentage over the CD4 count alone, in predicting HIV clinical progression.     

Cognitive impairment. Can it predict the course of hospitalized patients?

All patients admitted to three medical services at the New York Hospital during a one-month period were screened with Folstein's Mini-Mental State Examination. The prevalence of cognitive impairment was 19.8% (23 of 116). Cognitively "impaired" patients, ie, those with a Folstein score less than 24, were older, sicker, and less physiologically stable than the cognitively "intact." The in-hospital mortality (17 versus 5%) and morbidity (39 versus 18%) rates were higher for the cognitively "impaired" patients; these differences could be explained by the greater severity of illness, instability, and comorbidity found in these patients. Cognitively "impaired" patients were particularly susceptible to respiratory complications. Cognitively "impaired" patients had longer lengths of hospital stay, spent more time in hospital awaiting placement, and were more likely to be discharged to a nursing home or require home assistance than their cognitively "intact" counterparts. Three-month mortality rates were also higher for the cognitively "impaired" patients (30 versus 15%). These findings suggest that cognitive impairment on admission may be regarded as a marker for patients with poorer prognoses.     

Smokers hospitalized in an urban, public hospital: addiction, stages of change, and self-efficacy.

BACKGROUND: This study characterizes adult smokers on the medicine service of an urban, public hospital, including stage of change, self-efficacy to quit, and nicotine dependence, and explores relationships between perceived and actual smoking-related illness and these three predictive variables. METHODS: Adult patients (n = 154) admitted to the Medicine service of Denver Health Medical Center in October and November 1996 were surveyed using a written questionnaire. RESULTS: The proportion of smokers in this population was 45.7% (95% CI = 42.0%, 49.4%). Adjusted for age and sex, the proportion of smokers in this population was significantly greater than in Colorado (28.8% vs 21.8%, P < 0.001). About half (54.2%) were willing to try free nicotine patches during hospitalization. Among smokers with diseases recognized as smoking-related, 30.4% believed their reason for admission was related to smoking, compared to 20.4% among those with no smoking-related diseases (P = 0.18). Patients who believed their hospitalization was due to smoking had greater intentions (P = 0.001) and self-efficacy (P < 0.001) to quit. CONCLUSIONS: Targeting smokers who perceive that their illness is smoking-related may optimize inpatient smoking interventions.