Expansion of CD11abright cells in CD8+CD45RA+ from HIV-infected patients: a new early marker for disease progression?

CD8+CD45RA+ T lymphocytes present two distinct subpopulations expressing the CD11a molecule (LFA-1 alpha chain) with different intensity. CD11adim cells represent the unprimed population within the CD8+CD45RA+ subset, whereas CD11abright cells are activated and may be considered as memory lymphocytes. The aim of this study was to analyze the expression of CD11a and CD18 within the CD8+CD45RA+ population in young HIV-infected individuals at different stages of disease as a marker of activation and of disease progression. Blood cells from 82 HIV-infected individuals and 23 age-matched healthy controls were stained with unconjugated CD11a, CD18, PE-goat F(ab')2 anti-mouse, FITC-CD45RA, and TRI-Color CD8. Quantitative analysis for three-color immunofluorescence was carried out by flow cytometry. HIV+ subjects were subdivided into three groups according to their CD4+ cell number (group A, CD4+ cells > 500/microliters [20 subjects], group B, CD4+ cells between 500 and 200/microliters [36 subjects], and group C, CD4+ lymphocytes < 200/microliters [26 subjects]). We found a significant increase of CD11abright in the CD8+CD45RA+ subpopulation throughout the progression of the disease. The CD11abright percentage of positivity (mean) within the CD8+CD45RA+ subpopulation was 31% in healthy donors, 51% in group A, 52% in group B, and 68% in group C. CD11abright expression was closely related to CD18bright (p < 0.001), but not to CD38. The relative increase of CD11a and CD18 expression in CD8+CD45RA+ T lymphocytes parallels the decrease of CD4+ cells and the progression of disease: an inverse correlation between the percentages of CD4+ cells/microliter and CD8+CD45RA+CD11abright cells (p < 0.001) and a direct correlation between the number of CD4+ lymphocytes per microliter and both the number of CD8+CD45RA+CD11adim cells (p < 0.001) and the number of CD8+CD45RA+CD11abright (p = 0.002) was observed. The relative increase of CD8+CD45RA+CD11abright cells may represent an additional marker for monitoring HIV-induced immunodeficiency.

Food allergy and asthma.

Food allergy (FA) is one of the causes of atopic dermatitis (AD), of acute urticaria, of reactions of the gastrointestinal tract, and of acute systemic anaphylaxis, but its role in asthma appears to be less clear. The prevalence and incidence of subjects with food-induced wheezing have not been well studied. In addition, the number of subjects with proven food-induced wheezing by double-blind, placebo-controlled oral food challenge (DBPCOFC) has been small. At the moment wheezing is considered unusual in food-hypersensitive subjects, and wheezing as the unique symptom of FA is rare. Furthermore, most cases of food-induced asthma have been observed in children. Food allergy may trigger allergic respiratory symptoms through two main routes: ingestion or inhalation. Children with asthma, who are allergic to foods, present some particular features such as AD and a related significantly elevated total serum IgE level. Alternatively, FA may occur in patients who are "high IgE responder" and more prone to become sensitive to many allergens, including foods. Therefore, children with asthma and a history of AD and/or elevated total serum IgE level should be carefully assessed for FA. We have shown that a significant proportion of children with IgE-mediated cow's milk allergy experienced asthma following DBPCOFC with cow's milk.