Facilitation of penicillin haptenation to serum proteins.

Traditionally, penicillin binding to serum proteins was believed to be a passive chemical process; however, it appears to be facilitated by serum factors. The objectives of this in vitro investigation were to examine facilitated penicillin haptenation, to study the kinetics of haptenation, and to determine the nature of haptenation-facilitating factors. The model involved addition of [3H]benzylpenicillin to serum or albumin solutions (at pH 7.3 to 7.4) and incubation at 37 degrees C for up to 72 h. The extent of penicillin binding to proteins in serum was found to be four- to fivefold higher than with solutions having comparable concentrations of purified albumin, total protein, or total immunoglobulin. Ultrafiltration of serum reduced penicillin binding to serum proteinssubstantially. An ultrafiltrable haptenation-facilitating factor(s) was found to be less than 0.5 kDa but was not calcium or magnesium. Finally, the extent of penicillin binding was related to albumin purity, as binding substantially increased with albumin purity. These findings suggest that there is a factor(s) in serum that facilitates covalent binding of penicillin to serum proteins. The factor(s) can be removed and then restored to increase penicillin binding to albumin. It appears that at least one component of the facilitation factor is less than 0.5 kDa, which suggests that it is not a peptide and that it is some simple serum component other than calcium or magnesium

Lipopolysaccharide-reactive immunoglobulin E is associated with lower mortality and organ failure in traumatically injured patients

Antilipopolysaccharide (anti-LPS) immunoglobulin G (IgG) and IgM have been associated with protection from LPS effects in vivo. We investigated the presence of IgE and anti-LPS in 32 patients that had experienced severe traumatic injury and in 35 healthy volunteers; we also investigated whether IgE anti-LPS was associated with important clinical events. Plasma samples were collected daily from patients in the intensive care unit and on one occasion from volunteers; the samples were assayed for IgE anti-LPS. IgE anti-LPS was assayed by enzyme-linked immunosorbent assay with monoclonal anti-human IgE as the capture antibody. Detection was accomplished with biotin-labeled LPS (Escherichia coli J5 mutant) followed by streptavidin-peroxidase with 2,2\u27-azino(3-ethylbenzthiazoline)sulfonic acid as the substrate. The assay was demonstrated to be specific for IgE and LPS-biotin by nonreactivity of control sera with high-titer anti-LPS IgG and IgM and by inhibition with unlabeled LPS. IgE anti-LPS was detected in 1 of 35 healthy controls (2.9%o) and 25 of 32 traumatically injured patients (78%) (P \u3c 0.001). The presence of IgE anti-LPS was associated with a lower incidence of death (P = 0.026) and of renal failure (P = 0.0012). There was no apparent temporal relationship between detection of IgE anti-LPS and clinical events. IgG anti-LPS was detected more frequently in patients that were positive for IgE anti-LPS (P = 0.06) but was not associated with clinical events. The inability to detect IgE anti-LPS may be related to adverse clinical events through depletion of specific IgE due to LPS exposure after trauma or through saturation of the assay by IgE with other specificities. We have reported increased total IgE concentrations in these patients (J. T. DiPiro, R. G. Hamilton, T. R. Howdieshell, N. F. Adkinson, and A. R. Mansberger, Ann. Surg. 215:460-466, 1992)

Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.

Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma

A genome-wide survey of CD4+ lymphocyte regulatory genetic variants identifies novel asthma genes

Background: Genome-wide association studies have yet to identify the majority of genetic variants involved in asthma. We hypothesized that expression quantitative trait locus (eQTL) mapping can identify novel asthma genes by enabling prioritization of putative functional variants for association testing. Objective: We evaluated 6,706 cis-acting expression-associated variants (eSNP) identified through a genome-wide eQTL survey of CD4+ lymphocytes for association with asthma. Methods: eSNP were tested for association with asthma in 359 asthma cases and 846 controls from the Childhood Asthma Management Program, with verification using family-based testing. Significant associations were tested for replication in 579 parent-child trios with asthma from Costa Rica. Further functional validation was performed by Formaldehyde Assisted Isolation of Regulatory Elements (FAIRE)-qPCR and Chromatin-Immunoprecipitation (ChIP)-PCR in lung derived epithelial cell lines (Beas-2B and A549) and Jurkat cells, a leukemia cell line derived from T lymphocytes. Results: Cis-acting eSNP demonstrated associations with asthma in both cohorts. We confirmed the previously-reported association of ORMDL3/GSDMB variants with asthma (combined p=2.9 × 108). Reproducible associations were also observed for eSNP in three additional genes: FADS2 (p=0.002), NAGA (p=0.0002), and F13A1 (p=0.0001). We subsequently demonstrated that FADS2 mRNA is increased in CD4+ lymphocytes in asthmatics, and that the associated eSNPs reside within DNA segments with histone modifications that denote open chromatin status and confer enhancer activity. Conclusions: Our results demonstrate the utility of eQTL mapping in the identification of novel asthma genes, and provide evidence for the importance of FADS2, NAGA, and F13A1 in the pathogenesis of asthma

Patterns of Growth and Decline in Lung Function in Persistent Childhood Asthma

BACKGROUND: Tracking longitudinal measurements of growth and decline in lung function in patients with persistent childhood asthma may reveal links between asthma and subsequent chronic airflow obstruction. METHODS: We classified children with asthma according to four characteristic patterns of lung-function growth and decline on the basis of graphs showing forced expiratory volume in 1 second (FEV1), representing spirometric measurements performed from childhood into adulthood. Risk factors associated with abnormal patterns were also examined. To define normal values, we used FEV1 values from participants in the National Health and Nutrition Examination Survey who did not have asthma. RESULTS: Of the 684 study participants, 170 (25%) had a normal pattern of lung-function growth without early decline, and 514 (75%) had abnormal patterns: 176 (26%) had reduced growth and an early decline, 160 (23%) had reduced growth only, and 178 (26%) had normal growth and an early decline. Lower baseline values for FEV1, smaller bronchodilator response, airway hyperresponsiveness at baseline, and male sex were associated with reduced growth (P<0.001 for all comparisons). At the last spirometric measurement (mean [±SD] age, 26.0±1.8 years), 73 participants (11%) met Global Initiative for Chronic Obstructive Lung Disease spirometric criteria for lung-function impairment that was consistent with chronic obstructive pulmonary disease (COPD); these participants were more likely to have a reduced pattern of growth than a normal pattern (18% vs. 3%, P<0.001). CONCLUSIONS: Childhood impairment of lung function and male sex were the most significant predictors of abnormal longitudinal patterns of lung-function growth and decline. Children with persistent asthma and reduced growth of lung function are at increased risk for fixed airflow obstruction and possibly COPD in early adulthood. (Funded by the Parker B. Francis Foundation and others; ClinicalTrials.gov number, NCT00000575.

Middleton's Allergy

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