BACKGROUND: The aim of our study was to assess the influence of polyclonal antithymocyte globulins (ATGs) on the expression of adhesion molecules on lymphocytes, neutrophils, and thrombocytes by means of flow cytometry. ATGs are employed in various regimens for solid organ transplantation. Immunosuppression with ATGs may influence the expression of adhesion molecules on thrombocytes, lymphocytes, and neutrophils due to nonspecific antibodies directed against myeloid and nonmyeloid cells. MATERIAL AND METHODS: Depletion, activation, and expression of adhesion molecules on thrombocytes (CD41, CD42, CD62p and CD107a), neutrophils, and lymphocytes (CD11, CD18, CD62L) were studied in vitro in whole blood of healthy volunteers by means of flow cytometry after incubation with different dosages of three ATGs. RESULTS: Our data showed no ATG-mediated cytotoxic activity against platelets. ATGs were able, however, to induce activation of platelets through increased expression of P-selectin and hLAMP-1. ATGs also influenced the expression of adhesion molecules on lymphocytes and neutrophils by reducing the expression of CD62L. Furthermore, the effects of ATG on CD11/CD18 were dependent on the dosage and type of ATG. CONCLUSION: Polyclonal ATGs induced expression of adhesion molecules and activation of unstimulated thrombocytes as well as reduced the expression of adhesion molecules on lymphocytes and neutrophils. Increased adhesion of thrombocytes may be responsible for the undesirable side effects observed in clinical practice such as thrombocytopenia. However, reduction in the expression of adhesion molecules on lymphocytes and neutrophils may decrease the effects of ischemia/reperfusion injury.
BACKGROUND: The aim of our study was to assess the influence of polyclonal antithymocyte globulins (ATGs) on the expression of adhesion molecules on lymphocytes, neutrophils, and thrombocytes by means of flow cytometry. ATGs are employed in various regimens for solid organ transplantation. Immunosuppression with ATGs may influence the expression of adhesion molecules on thrombocytes, lymphocytes, and neutrophils due to nonspecific antibodies directed against myeloid and nonmyeloid cells. MATERIAL AND METHODS: Depletion, activation, and expression of adhesion molecules on thrombocytes (CD41, CD42, CD62p and CD107a), neutrophils, and lymphocytes (CD11, CD18, CD62L) were studied in vitro in whole blood of healthy volunteers by means of flow cytometry after incubation with different dosages of three ATGs. RESULTS: Our data showed no ATG-mediated cytotoxic activity against platelets. ATGs were able, however, to induce activation of platelets through increased expression of P-selectin and hLAMP-1. ATGs also influenced the expression of adhesion molecules on lymphocytes and neutrophils by reducing the expression of CD62L. Furthermore, the effects of ATG on CD11/CD18 were dependent on the dosage and type of ATG. CONCLUSION: Polyclonal ATGs induced expression of adhesion molecules and activation of unstimulated thrombocytes as well as reduced the expression of adhesion molecules on lymphocytes and neutrophils. Increased adhesion of thrombocytes may be responsible for the undesirable side effects observed in clinical practice such as thrombocytopenia. However, reduction in the expression of adhesion molecules on lymphocytes and neutrophils may decrease the effects of ischemia/reperfusion injury.
Authors: F Cicora; P Stringa; D Guerrieri; J Roberti; N Ambrosi; F Toniolo; P Cicora; G Palti; D Vásquez; C Raimondi Journal: Clin Exp Immunol Date: 2012-09 Impact factor: 4.330