Effects of All-Trans-retinoic acid on the immunosuppression associated to infectious processes in a murine model

MARTIRE GRECO, DAIANA; LANDONI, VERÓNICA; CHIARELLA, PAULA; SCHIERLOH, PABLO; REARTE, BÁRBARA; ISTURIZ, MARTÍN; FERNÁNDEZ, GABRIELA

Ciudad Autónoma de Buenos Aires

Congreso; First French - Argentine Immunology Congress; 2010

Sociedad Argentina de Inmunología-French Society of Immunology

Immunosuppresssion related to late phases of sepsis is a medical concern associated with high mortality rates. The model of tolerance to LPS mimics several aspects of sepsis-associated immunosuppression. In this sense an increase of myeloid-derived suppressor cells (MDSC, Gr-1+CD11b+CD31+) has been related to the derangements observed in the immune response. All-trans-retinoic acid (ATRA) is a derivative of vitamin-A with immunomodulating properties, that eliminates MDSC, inducing their differentiation. Our hypothesis is that ATRA could restore the immunological competence in the model of tolerance to LPS. We investigated the effects of ATRA on different immune parameters. Increasing i.p. doses of LPS were administered for 20 days and orally doses of ATRA were given for the last 13 days (LPS: 5 to 20 µg/day/mouse, ATRA: 500 µg/day/mouse). Using flow cytometry we observed that ATRA decreased the percentage (%) of MDSC in the spleen (LPS=1.67±0.17, LPS+ATRA=0.97±0.03, p