IngentaConnect Loratadine and desethoxylcarbonyl-loratadine inhibit theimmunolog...

Abstract:

Background Loratadine, a novel histamine H₁-receptor antagonist, is effective in the treatment of patients with seasonal and perennial rhinitis and some allergic skin disorders. Histamine and other chemical mediators are synthesized and immunologically released by human peripheral blood basophils and tissue mast cells (FcεRI⁺ cells). Objective To evaluate the effects of loratadine and its main metabolite, desethoxylcarbonyl-loratadine (des-loratadine), on the immunological release of preformed (histamine and tryptase) and de novo synthesized mediators (leukotriene C₄: LTC₄ and prostaglandin D₂: PGD₂) from human FcεRI⁺ cells. Methods Human FcεRI⁺ cells purified from peripheral blood and from skin (HSMC) and lung tissue (HLMC) were preincubated with loratadine and des-loratadine before immunological challenge with Der p 1 antigen or anti-FcεRI. The release of preformed mediators (histamine and tryptase) and de novo synthesized eicosanoids was evaluated in the supernatants of human FcεRI⁺ cells. Results Preincubation (15 min, 37 °C) of purified (36-74%) basophils with loratadine (3 × 10⁻⁶-10⁻⁴ M) and des-loratadine before Der p 1 antigen or anti-FcεRI challenge concentration-dependently (5-40%) inhibited the release of histamine and LTC₄. Loratadine (3 × 10⁻⁶-10⁻⁴ M) and des-loratadine also inhibited (10-40%) histamine, LTC₄, and PGD₂ release from purified HLMC (16-68%) activated by anti-FcεRI. Loratadine (3 × 10⁻⁶-10⁻⁴ M) and des-loratadine caused concentration-dependent inhibition (10-40%) of histamine, tryptase, LTC₄, and PGD₂ release from purified HSMC (24-72%) immunologically challenged with anti-FcεRI. Conclusion These results indicate that loratadine and its main metabolite have anti-inflammatory activity by inhibiting the release of preformed and de novo synthesized mediators from human FcεRI⁺ cells.

Keywords: basophils; histamine; leukotrienes; loratadine; mast cells; tryptase

Document Type: Research article

DOI: 10.1046/j.1365-2222.1997.270860.x

Affiliations: 1: Division of Clinical Immunology and Allergy, University of Naples Federico II School of Medicine, Naples, Italy

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Loratadine and desethoxylcarbonyl-loratadine inhibit the immunological release of mediators from human FcεRI+ cells

Loratadine and desethoxylcarbonyl-loratadine inhibit the immunological release of mediators from human FcεRI⁺ cells