Lewis Histo-Blood Group System and Associated Secretory Phenotypes

This review summarises present knowledge of the chemistry, immunology, genetics and clinical significance of antibodies in the Lewis and secretor histoblood group systems. Although red cell serology has laid the foundations for these systems, more recent advances have been made by studying Lewis and related glycoconjugates with monoclonal antibodies, determining structures by mass spectrometry and NMR spectroscopy, identifying enzymes and their specificities, and identifying the genes by molecular biology. The expression of Lewis system antigens is dependent on Lewis and secretor loci. Fucosyltransferases coded by genes at these loci compete and interact with each other and with other transferases to determine an individual's Lewis and secretor phenotype. Exocrine epithelial cells, mostly of endodermal origin, synthesise the Lewis antigens which, as plasma glycolipids, are secondarily acquired by cells of the peripheral circulation. Phenotyping red cells is often regarded as a simple way of determining the Lewis and sometimes the secretor status of an individual; however, the red cell phenotype is influenced by many factors and may not necessarily reflect someone's Lewis and secretor genotypes. Two main red cell Lewis groups are usually found, Lewis negative and Lewis positive. In Lewis-negative individuals, the secretor genotype does not affect the Lewis phenotype, but in Lewis-positive individuals, the non-secretor genotype generates the Le(a+b–) phenotype, the secretor genotype causes the Le(a–b+) phenotype, and the partial secretor genotype gives rise to the Le(a+b+) phenotype.     

Detection and Characterization of Lewis Antigens in Plasma of Lewis-Negative Individuals Evidence of Chain Extension as a Result of Reduced Fucosyltransferase Competition

Nonacid plasma glycolipids from Lewis-negative individuals of nonsecretor, partial-secretor and secretor phenotypes were prepared and separated by thin-layer chromatography and immunostained with radiolabelled Lewis antibodies. Lewis-positive plasma and intestinal epithelial cell glycolipids from Caucasians representing the four recognized Lewis and secretor combined phenotypes were used as controls. By presenting these purified total glycolipids in a cell-free environment to Lewis antibodies we were able to demonstrate the presence of small amounts of Lewis antigens in Lewis-negative individuals. It is shown that lactotetraosylceramide and extended precursor glycolipids are present in all Le(a–b–) nonsecretors. Le^awas detected in 1 of the 3 Le(a–b–) nonsecretor plasmas and in the intestinal sample of the same phenotype. Lactotetraosylceramide was absent but H type 1 and Le^bwere both present in all group O Le(a–b–) secretors, and extended H type 1 reactive structures were also found in the partial secretor. These results clearly demonstrate that although the Lewis-negative phenotype exists at the serological level, this phenotype is not an 'all-or-nothing' phenomenon at the chemical level. We also show that in the presence of reduced fucosyltransferase activity, increased elongation of the precursor chain occurs, which allows us to postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation.     

The mentored clinical casebook project at Harvard Medical School.

An excellent physician must be aware of the countless issues that affect each patient's health. Many medical education programs expose students to a broad spectrum of disparate knowledge and hope they will integrate all the pieces into a coherent whole. The authors describe an explicit approach to integration used at Harvard Medical School since 2003 that aims to enhance students' learning in medical school and throughout their medical careers: the Mentored Clinical Casebook Project (MCCP). The MCCP is constructed on the premise that such integration does not occur suddenly but, rather, is an unending process. A first-year student is assigned to one clinician and follows one patient for one year. The student is expected to spend as much time with the patient as possible, in both clinical and nonclinical settings, seek help from the clinician, and consult other experts and sources to develop a complete picture of the patient's life. The student must produce a casebook that includes, but is not limited to, the patient's history; basic science, clinical, socioeconomic, and cultural issues; and self-reflection. The MCCP is intended to allow students to develop a deeper and more diverse understanding of what comprises a patient's health care life, to discern the patient as a person and the person as a patient. This educational project has been popular with students since its inception, providing them with a personal framework from which to address the needs of future patients and introducing them to how much they will continue to learn from their patients.     

Cellular expression and genetic control of ABH antigens in primary sensory neurons of marmoset, baboon and man

ABH antigens have been demonstrated in the posterior root ganglia (PRG) of 3 primate species (marmoset, baboon and man). Their expression corresponded to the ABO phenotype of the individual and was independent of the secretor gene. In marmosets more cells were positive for H (33 +/- 9%) than for A (19 +/- 6%). In baboons A or B antigens were more easily detected (66 +/- 9%) than the H antigens (48 +/- 5%). In humans more than two-thirds of PRG cells were positive for H but only a small proportion of these were positive for A or B. The ABH antigens were found mainly in the small and intermediate-size neurons whose central processes project to lamina II of the spinal cord posterior horn. Unipolar neurons of the Gasserian ganglion, neurons of the mesencephalic nucleus of the trigeminal nerve and of some visceral ganglia have also been shown to express these antigens which are also present in the fibre layer and glomeruli of the olfactory bulbs.     

High prevalence of hepatitis B virus pre-s mutant in countries where it is endemic and its relationship with genotype and chronicity

It has been reported that hepatitis B virus (HBV) mutants carrying mutations in the pre-S region can be found in infected patients. In this study, we investigated the prevalence of the HBV variant with the pre-S mutant in different geographic regions, including countries with low and high levels of endemic HBV infection, and analyzed the correlation with clinical findings. We examined 387 HBV DNA-positive serum samples from individuals among 12 countries, consisting of Vietnam, Myanmar, Thailand, China, Korea, Nepal, Japan, Russia, Spain, United States, Bolivia, and Ghana. HBV pre-S mutants were detected in 71 (18.3%) of 387 serum samples tested. This mutant was the most prevalent in Vietnam (36%), followed by Nepal (27.3%), Myanmar (23.3%), China (22.4%), Korea (14.3%), Thailand (10.5%), Japan (7.7%), and Ghana (4.3%). In contrast, no case with this mutation was found in Russia, Spain, United States, and Bolivia. Among the HBV deletion mutations, 15.5% (11 of 71) occurred in the pre-S1 and 46.5% (33 of 71) in the pre-S2 regions. Eight (11.3%) cases had a mutation in both the pre-S1 and pre-S2 regions. In addition, a point mutation at the pre-S2 starting codon was observed in 19 (26.7%) cases. The detection rate of the HBV mutant in patients with hepatocellular carcinoma was significantly higher than in other patients (P < 0.05). Furthermore, these mutants were found more frequently in genotype B (25%) and genotype C (24.5%) than in the other genotypes (P < 0.05). Our results indicated that there was a high prevalence of HBV pre-S mutation in regions of endemic HBV infection in Asia. Furthermore, the pre-S mutation appeared to be correlated with hepatocellular carcinoma and HBV genotypes.     

Determination of Ole e 1 by enzyme immunoassay and scanning densitometry. Validation by skin-prick testing

Ole e 1 is an important allergen in Olea europaea pollen extracts. This study describes the development of two new methods that can be used to estimate the Ole e 1 content in olive tree pollen extracts. They are based on (1) an enzyme immunoassay that uses rabbit polyclonal, monospecific antibodies and purified Ole e 1, and (2) scanning densitometry of SDS-PAGE gels. Twelve extracts were evaluated by in vivo and in vitro methods. The in vivo biological potency was estimated by prick skin testing 17 allergic individuals; the in vitro allergenic potency by direct IgE and IgE inhibition assays. The enzyme immunoassay showed an operative range of 0.03-100 microg/ml and demonstrated to be specific for Ole e 1. The Ole e 1 content ranged from 1% to 5% of the total protein in the 12 extracts. The amount of Ole e 1, assessed by gel scanning densitometry significantly correlated with the Ole e 1 content obtained by the immunoassay (r = 0.92; p < 0.001). The Ole e 1 content showed a significant correlation with the total allergenic potency of the extracts, evaluated by direct IgE, specific IgE inhibition and skin-prick testing. These two methods can be used to determine the Ole e 1 content in olive pollen extracts. The content of Ole e 1 can vary from 1% to 5% of the total protein in the extracts.     

Two myeloma globulins, IgG1-kappa and IgG1-lambda, from a single patient (Im). I. Purification and immunochemical characterization

Electrophoretic analysis of the serum from a patient Im suffering from a multiple myeloma revealed the existence of two abnormal bands. Purification of these two fractions on a DEAE—cellulose column showed that both fractions had the same sedimentation coefficient (7S), belonged to the same class (IgG), and subclass (γl) and bore the same allotype (Gm₁). However, the heavy (H) chains of one immunoglobulin were associated with type κ light (L) chains whereas those of the other were associated with type λ L chains.Three individual antigenic determinants were found in these two proteins. One was common to the H chains of both proteins and the other two were each specific to one of the L chains. These results suggest that the myeloma cells of patient (Im) were able to produce at least three polypeptide chains, one H chain and two different types of L chains.     

Comparison of the allergenicity and Ole e 1 content of 6 varieties of Olea europaea pollen collected during 5 consecutive years.

BACKGROUND: Numerous varieties of Olea europaea have been described in Mediterranean countries. OBJECTIVE: To investigate the immunochemical characteristics of 6 varieties of Olea europaea collected during 5 consecutive years. METHODS: The varieties Carrasquefio, Manzanillo, Acebuche (wild olive), Hojiblanco, Picual, and Nevado were analyzed. Pollen samples from each variety were collected for 5 consecutive years from the same cultivars by trained personnel. The antigenic and allergenic profiles of these extracts were evaluated by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot using the serum of 29 O. europaea-allergic individuals. Ole e 1 was measured using enzyme-linked immunosorbent assay and purified Ole e 1 and rabbit polyclonal antibodies. Allergenic potency was determined using enzyme-linked immunosorbent assay inhibition and is expressed in histamine equivalent prick units per gram of raw material. RESULTS: Hojiblanco and Acebuche had the lowest mean +/- SD Ole e 1 content in the 5 years (0.045 +/- 0.029 and 0.059 +/-0.031 microg/microg of freeze-dried material, respectively). The variety with the highest mean +/- SD Ole e 1 content was Picual (0.19 +/-0.075 microg/microg). Hojiblanco had the lowest total biological potency throughout the study. A positive correlation was obtained between rainfall in the winter months and total allergenicity of the 6 varieties. CONCLUSIONS: The different varieties of O. europaea pollen demonstrated great differences in allergenic potency and Ole e 1 content. These differences were maintained throughout the study, suggesting that they are due to genetic differences intrinsic to the varieties, although certain climatic effects may also play a role.     

Soluble suppression of tumorigenicity-2 predicts pneumonia in patients with inhalation injury: Results of a pilot study

IntroductionSeveral mechanisms play a role in the development of pneumonia after inhalation injury. Our aim was to analyze whether higher concentrations of inflammatory markers or of biomarkers of epithelial injury are associated with a higher incidence of pneumonia in patients with inhalation injury.Material and methodsSecondary analysis of a single-center prospective observational cohort pilot study, performed over a two-year period (2015–2017) at the Burns Unit of the Plastic and Reconstructive Surgery Department of Vall d’Hebron University Hospital. All patients aged 18 with suspected inhalation injury undergoing admission to the Burns Unit were included. Plasma biomarkers of the lung epithelium (RAGE and SP-D), inflammation markers (IL6, IL8), and IL33, as well as soluble suppression of tumorigenicity-2 (sST2) levels, were measured within the first 24 h of admission.ResultsTwenty-four patients with inhalation injury were included. Eight (33.3%) developed pneumonia after a median of 7 (4–8) days of hospital stay. Patients with pneumonia presented higher plasma concentrations of sST2 (2853 [2356–3351] ng/mL vs 1352 [865–1839] ng/mL; p < 0.001), IL33 (1.95 [1.31–2.59] pg/mL vs 1.26 [1.07–1.45] pg/mL; p = 0.002) and IL8 (325.7 [221.6–430.0] pg/mL vs 174.1 [95.2–253.0] pg/mL; p = 0.017) on day 1 of inclusion. Plasma sST2 concentration in the first 24 h demonstrated excellent diagnostic accuracy for predicting the occurrence of pneumonia in patients with smoke inhalation (AUROC 0.929 [95%CI 0.818–1.000]). A cutoff point of ≥2825 ng/mL for sST2 had a sensitivity of 75% and a specificity of 100%. The risk ratio of pneumonia in patients with sST2 ≥ 2825 ng/mL was 7.14 ([95% CI 1.56–32.61]; p = 0.016).ConclusionsPlasma sST2 in the first 24 h of admission predicts the occurrence of pneumonia in patients with inhalation injury.