Determination of the Frequency of Myeloid-derived Suppressor Cells during Human Active Tuberculosis

CASTELLO, FLORENCIA A.; MORELLI, MARÍA P.; PELLEGRINI, JOAQUÍN M.; CASCO, N; CIALLELLA, L; CASTAGNINO J; GALLEGO C; PALMERO, DJ; GARCIA, VE; TATEOSIAN, NANCY L.

Congreso; Reunión Anual de la Sociedad Argentina de Inmunología; 2018

Tuberculosis (TB), together with HIV infection, is the leading cause of death from aninfectious disease worldwide. In fact, Mycobacterium tuberculosis (Mtb) causes almost 10million of new cases and 1.5 million deaths per year. Human myeloid-derived suppressorcells (MDSC) have been described as a group of immature myeloid cells which exertimmunosuppressive action by inhibiting function of T lymphocytes. There are two differenttypes of MDSC, as identified in studies in both mice and humans: granulocytic MDSC (g-MDSC) are morphologically and phenotypically similar to neutrophils, whereas monocyticMDSC (m-MDSC) are similar to monocytes. MDSCs display an immunosuppressive functionduring several pathological conditions such as cancer and hepatitis. MDSC-mediatedsuppression of host immunity during chronic inflammation is crucial for immune regulationand tolerance to limit immunopathology. Furthermore, the unfavorable effects of MDSCs areevident in tumor biology where they accumulate and suppress cytokines Th1 responses.Nevertheless, no evidence of a functional role for MDSCs in human TB exists. Wehypothesized that patients with active TB would have higher frequencies of MDSCscompared to healthy control subjects. Therefore, the aim of this work was to study theexpression of MDSCs during active TB.