Dynamics of cytokine mRNA expression and fecal biomarkers in school-children undergoing a double-blind placebo-controlled food challenge series.

BACKGROUND: There is need for prognostic markers for symptomatic food allergy since current diagnostic methods are insufficient and/or time and labor consuming. OBJECTIVE: To estimate the cytokine mRNA profiles in peripheral blood mononuclear cells (PBMC) before and after a double-blind placebo-controlled food challenge series in schoolchildren with suspected allergy to milk, egg or cod and in healthy controls. Analyses of fecal inflammatory biomarkers before and after the challenge were included. METHODS: Twelve-year-old children from a population-based cohort reporting complete avoidance of milk, egg, cod or wheat due to perceived hypersensitivity were clinically examined and those with suspected food allergy were evaluated with a 3-session double-blind placebo-controlled food challenge (n=18). Seven healthy controls participated in a double-blind challenge with egg. Before and after the challenge series, the cytokine mRNA expression was quantified for 13 cytokines discriminating between humoral Th2-, cytotoxic Th1-, regulatory Th3/Tr1- and inflammatory responses. Fecal calprotectin and eosinophil-derived neurotoxin (EDN) were also analyzed in children with suspected food allergy before and after the challenge series. RESULTS: Pre challenge, children with suspected food allergy had higher IL-13andTNF-α expression and lower IFN-γ and IL-15 expression compared to healthy controls (all p<0.05). Children with challenge-proven food allergy had increased IL13andIL-10 expression compared to the levels seen in negative challenges (p<0.05). Post challenge, IL-1ß and IL-6 mRNA levels were elevated in the food allergic children compared to controls (p<0.05). Fecal calprotectin and EDN levels were higher in challenge-proven food allergy compared to a negative challenge although not statistically significantly. CONCLUSION & CLINICAL RELEVANCE: Increased baseline mRNA levels of the Th2-related cytokine IL-13 and the regulatory cytokine IL-10 predicted a positive food challenge outcome. These cytokines in combination with fecal calprotectin and EDN might serve as future prognostic markers for symptomatic, IgE-mediated food allergy but need further validation in a larger patient cohort.

Induction of cell death in T lymphocytes by invasin via beta1-integrin.

Ligand binding to beta1-integrins exerts multiple effects on cells of the immune system including adhesion, spreading, haptotaxis and costimulation of T cells activated by anti-CD3. Here we show that a high-affinity ligand for beta1-integrins, the invasin (Inv) protein of Yersinia pseudotuberculosis, can induce cell death in T lymphocytes via a rapid process. Partially purified native Inv protein and an Inv fusion protein caused apoptotic/necrotic caspase-independent cell death in T lymphocytes as determined by phosphatidylserine exposure on the cell surface, uptake of propidium iodide, labeling of DNA strand breaks and presence of DNA ladder. Inv-induced cell death was mediated via beta1-integrins as indicated by the fact that Inv bound to the beta1-integrin subunit (CD29), that anti-beta(1)-integrin antibodies blocked Inv-induced cell death and that Inv-induced cell death was absent in two beta1-integrin- cell lines produced by different procedures. Killing via beta1-integrins represents a novel pathway for cell death in T lymphocytes.

T lymphocyte expression of thrombospondin-1 and adhesion to extracellular matrix components.

The mechanisms controlling the formation of pseudopodia and other active cell edges in T lymphocytes are not understood. We show here that T lymphocytes express thrombospondin-1 (TSP-1). TSP-1 in T lymphocytes has a high turnover as shown by the fact that brefeldin and monensin rapidly increase while cycloheximide tend to decrease the cellular TSP-1 content. T cell TSP-1 is preferentially stored intracellularly and shows variable cell surface expression. T lymphocyte adhesion to fibronectin and collagen type IV induces TSP-1 expression on the cell surface via a brefeldin sensitive mechanism. A monoclonal antibody to TSP-1 inhibits the flattening and pseudopodia formation of the adherent T cells. Furthermore, the same antibody to TSP-1 also exerts an inhibitory effect on T cell migration in the absence of exogenous TSP-1. These results indicate that endogenous TSP-1 is part of an adhesion-dependent mechanism controlling cytoplasmic spreading and migration in T lymphocytes.

Inmunidad celular y humoral en niños con hepatitis B / Cellular and humoral immunity in children with hepatitis B

Se determinaron las poblaciones linfocitarias T por las pruebas de rosetas activas (RA) y espontáneas (RE) y los anticuerpos monoclonales IOR T3 (CD3), IOR T4 (CD4), IOR T8 (CD8), así como el análisis del índice T4/T8 en 49 niños con infección del virus B: 24 pacientes presentaban este virus y 25 el de hepatitis crónica; se incluyen además, 10 niños sanos como grupo control. Se observó diferencia significativa de las rosetas activas entre grupos de estudio y con respecto al control. Las subpoblaciones linfoides en los grupos que se estudiaron no presentaron diferencias en relación con el control, aunque el índice T4/T8 resultó inferior en los de hepatitis crónica. Los inmunocomplejos séricos aumentaron con una mayor proporción en aquellos pacientes con daño hepático

Estudio a largo plazo de pacientes con hepatitis cronica activa tratados con interferon leucocitario

Siete pacientes con hepatitis crónica activa tratados con Interferón Alfa mostraron una notable mejoría humoral e histológica un año después de finalizado el tratamiento, en 3 de ellos la histología hepática era prácticamente normal, 2 evolucionaron a una Hepatitis Crónica persistente y sólo se apreció un empeoramiento en uno de ellos. Estos resultados difirieron de los obtenidos inmediatamente al final del tratamiento (p < 0,05). El Interferón Alfa resulta de gran utilidad en esta afección, debiendo continuarse el estudio de los pacientes hasta un año después de finalizado el tratamiento