title: Impairment of the inhibitory effect of sodium on basophil histamine release in patients with systemic sclerosis.
abstract: It has been demonstrated that Na+ down-regulates IgE-dependent and IgE-independent histamine release from basophils of normal subjects. The aim of this study was to evaluate whether Na+ exerts its inhibitory effect on basophil histamine release in patients with systemic sclerosis (SSc). Peripheral blood leucocytes were stimulated with anti-IgE, n-formyl-methionyl-leucyl-phenylalanine (fMLP) and IL-3 in the presence of high and low Na+ concentrations, and histamine release was measured by a fluorometric method. The dose-response curves of histamine release induced by the above stimuli were similar in SSc patients (n=15) and in normal subjects (n=39). Na+ removal from the extracellular medium and its isosmotic replacement with choline chloride led to a significant increase of anti-IgE-and fMLP-induced histamine release in normal subjects, but not in SSc patients. In the former population, histamine release induced by an optimal dose of anti-IgE (1/5000) was 26.4+/-3.1% in high Na+ and 59.3+/-3.5% in low Na+ (mean+/-s.e.m., P<0.0001), whereas in the latter population mean histamine release was 20.4+/-5.1% in high Na+ and 15.8+or-2.9% in low Na+ (p NS). A similar trend was observed when basophils were stimulated with fMLP. Na+ exerted a dose-dependent inhibitory effect on anti-IgE- and fMLP-induced histamine release in normal subjects, but not in SSc patients. IL-3-induced histamine release from basophils of SSc patients was increased in a low-Na+ solution, but to a lesser extent when compared with normal controls. Therefore basophils from normal subjects and SSc patients behave in a different way when stimulated in a low-Na+ medium. The inhibitory effect of Na+ on basophil histamine release is impaired in SSc patients, and this abnormality could contribute to basophil dysfunction.
authors.affiliation: Respiratory Allergy and Immunology Unit, Department of Internal Medicine, University of Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Tedeschi
authors.forename: M
authors.initials: M
authors.lastname: Palella
authors.forename: N
authors.initials: N
authors.lastname: Milazzo
authors.forename: B
authors.initials: B
authors.lastname: Mascagni
authors.forename: A
authors.initials: A
authors.lastname: Miadonna
mesh_terms: D000368:Aged; D001491:Basophils / Q000276:immunology*; D005260:Female; D006636:Histamine Release / Q000187:drug effects*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007377:Interleukin-3 / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D012595:Scleroderma, Systemic / Q000276:immunology*; D012964:Sodium / Q000494:pharmacology*
chemical_list: D007377:Interleukin-3; D007073:Immunoglobulin E; D009240:N-Formylmethionine Leucyl-Phenylalanine; D012964:Sodium