TY - JOUR
T1 - Antiallergic activity of loratadine
T2 - Inhibition of leukotriene C4 release from human leucocytes
AU - Miadonna, A.
AU - Milazzo, N.
AU - Lorini, M.
AU - Marchesi, E.
AU - Tedeschi, A.
PY - 1995
Y1 - 1995
N2 - The H1 antagonist loratadine has the capacity to inhibit histamine release from human basophils. The aim of this study was to investigate whether loratadine can also inhibit leukotriene C4 (LTC4) release from human leucocytes. Basophil-enriched mononuclear cell suspensions were prepared by centrifugation of peripheral venous blood (n = 10) on discontinuous Percoll gradients. Leucocytes were stimulated with anti-IgE, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and Ca2+ ionophore A23187; immunoreactive (i) LTC4 release in the cell supernatant was measured by a competitive radioimmunoassay and histamine release was evaluated by an automated fluorometric; technique. Loratadine, in the concentration range of 1-50 μM, exerted a dose-dependent inhibitory effect on IgE-mediated and IgE-independent histamine and iLTC4 release. The concentrations inhibiting 50% of histamine release were 30 μM (anti-IgE), 27 μM (FMLP) and l9 μM (Ca2+ ionophore A23187). The concentrations inhibiting 50% of iLTC4 release were 2.3 μM (anti-IgE). 11 μM (FMLP) and 1.7 μM (Ca2+ ionophore A23187). The inhibitory activity on iLTC4 release was optimal after preincubation for 2h at 37°C, and was no longer evident when leucocytes were stimulated 2 h after cell washing. Increased extracellular Ca2+ concentrations reduced the inhibitory activity of loratadine. These results indicate that loratadine has the capacity to inhibit the release of preformed and newly generated mediators from human basophil-enriched mononuclear cell suspensions.
AB - The H1 antagonist loratadine has the capacity to inhibit histamine release from human basophils. The aim of this study was to investigate whether loratadine can also inhibit leukotriene C4 (LTC4) release from human leucocytes. Basophil-enriched mononuclear cell suspensions were prepared by centrifugation of peripheral venous blood (n = 10) on discontinuous Percoll gradients. Leucocytes were stimulated with anti-IgE, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and Ca2+ ionophore A23187; immunoreactive (i) LTC4 release in the cell supernatant was measured by a competitive radioimmunoassay and histamine release was evaluated by an automated fluorometric; technique. Loratadine, in the concentration range of 1-50 μM, exerted a dose-dependent inhibitory effect on IgE-mediated and IgE-independent histamine and iLTC4 release. The concentrations inhibiting 50% of histamine release were 30 μM (anti-IgE), 27 μM (FMLP) and l9 μM (Ca2+ ionophore A23187). The concentrations inhibiting 50% of iLTC4 release were 2.3 μM (anti-IgE). 11 μM (FMLP) and 1.7 μM (Ca2+ ionophore A23187). The inhibitory activity on iLTC4 release was optimal after preincubation for 2h at 37°C, and was no longer evident when leucocytes were stimulated 2 h after cell washing. Increased extracellular Ca2+ concentrations reduced the inhibitory activity of loratadine. These results indicate that loratadine has the capacity to inhibit the release of preformed and newly generated mediators from human basophil-enriched mononuclear cell suspensions.
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M3 - Article
C2 - 7541309
AN - SCOPUS:0028906626
VL - 25
SP - 364
EP - 370
JO - Clinical and Experimental Allergy
JF - Clinical and Experimental Allergy
SN - 0954-7894
IS - 4
ER -